v4.19.13 snapshot.
diff --git a/fs/jbd2/Kconfig b/fs/jbd2/Kconfig
new file mode 100644
index 0000000..5a9f553
--- /dev/null
+++ b/fs/jbd2/Kconfig
@@ -0,0 +1,35 @@
+config JBD2
+ tristate
+ select CRC32
+ select CRYPTO
+ select CRYPTO_CRC32C
+ help
+ This is a generic journaling layer for block devices that support
+ both 32-bit and 64-bit block numbers. It is currently used by
+ the ext4 and OCFS2 filesystems, but it could also be used to add
+ journal support to other file systems or block devices such
+ as RAID or LVM.
+
+ If you are using ext4 or OCFS2, you need to say Y here.
+ If you are not using ext4 or OCFS2 then you will
+ probably want to say N.
+
+ To compile this device as a module, choose M here. The module will be
+ called jbd2. If you are compiling ext4 or OCFS2 into the kernel,
+ you cannot compile this code as a module.
+
+config JBD2_DEBUG
+ bool "JBD2 (ext4) debugging support"
+ depends on JBD2
+ help
+ If you are using the ext4 journaled file system (or
+ potentially any other filesystem/device using JBD2), this option
+ allows you to enable debugging output while the system is running,
+ in order to help track down any problems you are having.
+ By default, the debugging output will be turned off.
+
+ If you select Y here, then you will be able to turn on debugging
+ with "echo N > /sys/module/jbd2/parameters/jbd2_debug", where N is a
+ number between 1 and 5. The higher the number, the more debugging
+ output is generated. To turn debugging off again, do
+ "echo 0 > /sys/module/jbd2/parameters/jbd2_debug".
diff --git a/fs/jbd2/Makefile b/fs/jbd2/Makefile
new file mode 100644
index 0000000..802a341
--- /dev/null
+++ b/fs/jbd2/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the linux journaling routines.
+#
+
+obj-$(CONFIG_JBD2) += jbd2.o
+
+jbd2-objs := transaction.o commit.o recovery.o checkpoint.o revoke.o journal.o
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
new file mode 100644
index 0000000..26f8d7e
--- /dev/null
+++ b/fs/jbd2/checkpoint.c
@@ -0,0 +1,666 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/checkpoint.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1999 Red Hat Software --- All Rights Reserved
+ *
+ * Checkpoint routines for the generic filesystem journaling code.
+ * Part of the ext2fs journaling system.
+ *
+ * Checkpointing is the process of ensuring that a section of the log is
+ * committed fully to disk, so that that portion of the log can be
+ * reused.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <trace/events/jbd2.h>
+
+/*
+ * Unlink a buffer from a transaction checkpoint list.
+ *
+ * Called with j_list_lock held.
+ */
+static inline void __buffer_unlink_first(struct journal_head *jh)
+{
+ transaction_t *transaction = jh->b_cp_transaction;
+
+ jh->b_cpnext->b_cpprev = jh->b_cpprev;
+ jh->b_cpprev->b_cpnext = jh->b_cpnext;
+ if (transaction->t_checkpoint_list == jh) {
+ transaction->t_checkpoint_list = jh->b_cpnext;
+ if (transaction->t_checkpoint_list == jh)
+ transaction->t_checkpoint_list = NULL;
+ }
+}
+
+/*
+ * Unlink a buffer from a transaction checkpoint(io) list.
+ *
+ * Called with j_list_lock held.
+ */
+static inline void __buffer_unlink(struct journal_head *jh)
+{
+ transaction_t *transaction = jh->b_cp_transaction;
+
+ __buffer_unlink_first(jh);
+ if (transaction->t_checkpoint_io_list == jh) {
+ transaction->t_checkpoint_io_list = jh->b_cpnext;
+ if (transaction->t_checkpoint_io_list == jh)
+ transaction->t_checkpoint_io_list = NULL;
+ }
+}
+
+/*
+ * Move a buffer from the checkpoint list to the checkpoint io list
+ *
+ * Called with j_list_lock held
+ */
+static inline void __buffer_relink_io(struct journal_head *jh)
+{
+ transaction_t *transaction = jh->b_cp_transaction;
+
+ __buffer_unlink_first(jh);
+
+ if (!transaction->t_checkpoint_io_list) {
+ jh->b_cpnext = jh->b_cpprev = jh;
+ } else {
+ jh->b_cpnext = transaction->t_checkpoint_io_list;
+ jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev;
+ jh->b_cpprev->b_cpnext = jh;
+ jh->b_cpnext->b_cpprev = jh;
+ }
+ transaction->t_checkpoint_io_list = jh;
+}
+
+/*
+ * Try to release a checkpointed buffer from its transaction.
+ * Returns 1 if we released it and 2 if we also released the
+ * whole transaction.
+ *
+ * Requires j_list_lock
+ */
+static int __try_to_free_cp_buf(struct journal_head *jh)
+{
+ int ret = 0;
+ struct buffer_head *bh = jh2bh(jh);
+
+ if (jh->b_transaction == NULL && !buffer_locked(bh) &&
+ !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
+ JBUFFER_TRACE(jh, "remove from checkpoint list");
+ ret = __jbd2_journal_remove_checkpoint(jh) + 1;
+ }
+ return ret;
+}
+
+/*
+ * __jbd2_log_wait_for_space: wait until there is space in the journal.
+ *
+ * Called under j-state_lock *only*. It will be unlocked if we have to wait
+ * for a checkpoint to free up some space in the log.
+ */
+void __jbd2_log_wait_for_space(journal_t *journal)
+{
+ int nblocks, space_left;
+ /* assert_spin_locked(&journal->j_state_lock); */
+
+ nblocks = jbd2_space_needed(journal);
+ while (jbd2_log_space_left(journal) < nblocks) {
+ write_unlock(&journal->j_state_lock);
+ mutex_lock(&journal->j_checkpoint_mutex);
+
+ /*
+ * Test again, another process may have checkpointed while we
+ * were waiting for the checkpoint lock. If there are no
+ * transactions ready to be checkpointed, try to recover
+ * journal space by calling cleanup_journal_tail(), and if
+ * that doesn't work, by waiting for the currently committing
+ * transaction to complete. If there is absolutely no way
+ * to make progress, this is either a BUG or corrupted
+ * filesystem, so abort the journal and leave a stack
+ * trace for forensic evidence.
+ */
+ write_lock(&journal->j_state_lock);
+ if (journal->j_flags & JBD2_ABORT) {
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ return;
+ }
+ spin_lock(&journal->j_list_lock);
+ nblocks = jbd2_space_needed(journal);
+ space_left = jbd2_log_space_left(journal);
+ if (space_left < nblocks) {
+ int chkpt = journal->j_checkpoint_transactions != NULL;
+ tid_t tid = 0;
+
+ if (journal->j_committing_transaction)
+ tid = journal->j_committing_transaction->t_tid;
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ if (chkpt) {
+ jbd2_log_do_checkpoint(journal);
+ } else if (jbd2_cleanup_journal_tail(journal) == 0) {
+ /* We were able to recover space; yay! */
+ ;
+ } else if (tid) {
+ /*
+ * jbd2_journal_commit_transaction() may want
+ * to take the checkpoint_mutex if JBD2_FLUSHED
+ * is set. So we need to temporarily drop it.
+ */
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ jbd2_log_wait_commit(journal, tid);
+ write_lock(&journal->j_state_lock);
+ continue;
+ } else {
+ printk(KERN_ERR "%s: needed %d blocks and "
+ "only had %d space available\n",
+ __func__, nblocks, space_left);
+ printk(KERN_ERR "%s: no way to get more "
+ "journal space in %s\n", __func__,
+ journal->j_devname);
+ WARN_ON(1);
+ jbd2_journal_abort(journal, 0);
+ }
+ write_lock(&journal->j_state_lock);
+ } else {
+ spin_unlock(&journal->j_list_lock);
+ }
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
+}
+
+static void
+__flush_batch(journal_t *journal, int *batch_count)
+{
+ int i;
+ struct blk_plug plug;
+
+ blk_start_plug(&plug);
+ for (i = 0; i < *batch_count; i++)
+ write_dirty_buffer(journal->j_chkpt_bhs[i], REQ_SYNC);
+ blk_finish_plug(&plug);
+
+ for (i = 0; i < *batch_count; i++) {
+ struct buffer_head *bh = journal->j_chkpt_bhs[i];
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ }
+ *batch_count = 0;
+}
+
+/*
+ * Perform an actual checkpoint. We take the first transaction on the
+ * list of transactions to be checkpointed and send all its buffers
+ * to disk. We submit larger chunks of data at once.
+ *
+ * The journal should be locked before calling this function.
+ * Called with j_checkpoint_mutex held.
+ */
+int jbd2_log_do_checkpoint(journal_t *journal)
+{
+ struct journal_head *jh;
+ struct buffer_head *bh;
+ transaction_t *transaction;
+ tid_t this_tid;
+ int result, batch_count = 0;
+
+ jbd_debug(1, "Start checkpoint\n");
+
+ /*
+ * First thing: if there are any transactions in the log which
+ * don't need checkpointing, just eliminate them from the
+ * journal straight away.
+ */
+ result = jbd2_cleanup_journal_tail(journal);
+ trace_jbd2_checkpoint(journal, result);
+ jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
+ if (result <= 0)
+ return result;
+
+ /*
+ * OK, we need to start writing disk blocks. Take one transaction
+ * and write it.
+ */
+ result = 0;
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions)
+ goto out;
+ transaction = journal->j_checkpoint_transactions;
+ if (transaction->t_chp_stats.cs_chp_time == 0)
+ transaction->t_chp_stats.cs_chp_time = jiffies;
+ this_tid = transaction->t_tid;
+restart:
+ /*
+ * If someone cleaned up this transaction while we slept, we're
+ * done (maybe it's a new transaction, but it fell at the same
+ * address).
+ */
+ if (journal->j_checkpoint_transactions != transaction ||
+ transaction->t_tid != this_tid)
+ goto out;
+
+ /* checkpoint all of the transaction's buffers */
+ while (transaction->t_checkpoint_list) {
+ jh = transaction->t_checkpoint_list;
+ bh = jh2bh(jh);
+
+ if (buffer_locked(bh)) {
+ get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
+ wait_on_buffer(bh);
+ /* the journal_head may have gone by now */
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ goto retry;
+ }
+ if (jh->b_transaction != NULL) {
+ transaction_t *t = jh->b_transaction;
+ tid_t tid = t->t_tid;
+
+ transaction->t_chp_stats.cs_forced_to_close++;
+ spin_unlock(&journal->j_list_lock);
+ if (unlikely(journal->j_flags & JBD2_UNMOUNT))
+ /*
+ * The journal thread is dead; so
+ * starting and waiting for a commit
+ * to finish will cause us to wait for
+ * a _very_ long time.
+ */
+ printk(KERN_ERR
+ "JBD2: %s: Waiting for Godot: block %llu\n",
+ journal->j_devname, (unsigned long long) bh->b_blocknr);
+
+ jbd2_log_start_commit(journal, tid);
+ jbd2_log_wait_commit(journal, tid);
+ goto retry;
+ }
+ if (!buffer_dirty(bh)) {
+ if (unlikely(buffer_write_io_error(bh)) && !result)
+ result = -EIO;
+ BUFFER_TRACE(bh, "remove from checkpoint");
+ if (__jbd2_journal_remove_checkpoint(jh))
+ /* The transaction was released; we're done */
+ goto out;
+ continue;
+ }
+ /*
+ * Important: we are about to write the buffer, and
+ * possibly block, while still holding the journal
+ * lock. We cannot afford to let the transaction
+ * logic start messing around with this buffer before
+ * we write it to disk, as that would break
+ * recoverability.
+ */
+ BUFFER_TRACE(bh, "queue");
+ get_bh(bh);
+ J_ASSERT_BH(bh, !buffer_jwrite(bh));
+ journal->j_chkpt_bhs[batch_count++] = bh;
+ __buffer_relink_io(jh);
+ transaction->t_chp_stats.cs_written++;
+ if ((batch_count == JBD2_NR_BATCH) ||
+ need_resched() ||
+ spin_needbreak(&journal->j_list_lock))
+ goto unlock_and_flush;
+ }
+
+ if (batch_count) {
+ unlock_and_flush:
+ spin_unlock(&journal->j_list_lock);
+ retry:
+ if (batch_count)
+ __flush_batch(journal, &batch_count);
+ spin_lock(&journal->j_list_lock);
+ goto restart;
+ }
+
+ /*
+ * Now we issued all of the transaction's buffers, let's deal
+ * with the buffers that are out for I/O.
+ */
+restart2:
+ /* Did somebody clean up the transaction in the meanwhile? */
+ if (journal->j_checkpoint_transactions != transaction ||
+ transaction->t_tid != this_tid)
+ goto out;
+
+ while (transaction->t_checkpoint_io_list) {
+ jh = transaction->t_checkpoint_io_list;
+ bh = jh2bh(jh);
+ if (buffer_locked(bh)) {
+ get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
+ wait_on_buffer(bh);
+ /* the journal_head may have gone by now */
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ spin_lock(&journal->j_list_lock);
+ goto restart2;
+ }
+ if (unlikely(buffer_write_io_error(bh)) && !result)
+ result = -EIO;
+
+ /*
+ * Now in whatever state the buffer currently is, we
+ * know that it has been written out and so we can
+ * drop it from the list
+ */
+ if (__jbd2_journal_remove_checkpoint(jh))
+ break;
+ }
+out:
+ spin_unlock(&journal->j_list_lock);
+ if (result < 0)
+ jbd2_journal_abort(journal, result);
+ else
+ result = jbd2_cleanup_journal_tail(journal);
+
+ return (result < 0) ? result : 0;
+}
+
+/*
+ * Check the list of checkpoint transactions for the journal to see if
+ * we have already got rid of any since the last update of the log tail
+ * in the journal superblock. If so, we can instantly roll the
+ * superblock forward to remove those transactions from the log.
+ *
+ * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
+ *
+ * Called with the journal lock held.
+ *
+ * This is the only part of the journaling code which really needs to be
+ * aware of transaction aborts. Checkpointing involves writing to the
+ * main filesystem area rather than to the journal, so it can proceed
+ * even in abort state, but we must not update the super block if
+ * checkpointing may have failed. Otherwise, we would lose some metadata
+ * buffers which should be written-back to the filesystem.
+ */
+
+int jbd2_cleanup_journal_tail(journal_t *journal)
+{
+ tid_t first_tid;
+ unsigned long blocknr;
+
+ if (is_journal_aborted(journal))
+ return -EIO;
+
+ if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
+ return 1;
+ J_ASSERT(blocknr != 0);
+
+ /*
+ * We need to make sure that any blocks that were recently written out
+ * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
+ * we drop the transactions from the journal. It's unlikely this will
+ * be necessary, especially with an appropriately sized journal, but we
+ * need this to guarantee correctness. Fortunately
+ * jbd2_cleanup_journal_tail() doesn't get called all that often.
+ */
+ if (journal->j_flags & JBD2_BARRIER)
+ blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
+
+ return __jbd2_update_log_tail(journal, first_tid, blocknr);
+}
+
+
+/* Checkpoint list management */
+
+/*
+ * journal_clean_one_cp_list
+ *
+ * Find all the written-back checkpoint buffers in the given list and
+ * release them. If 'destroy' is set, clean all buffers unconditionally.
+ *
+ * Called with j_list_lock held.
+ * Returns 1 if we freed the transaction, 0 otherwise.
+ */
+static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy)
+{
+ struct journal_head *last_jh;
+ struct journal_head *next_jh = jh;
+ int ret;
+
+ if (!jh)
+ return 0;
+
+ last_jh = jh->b_cpprev;
+ do {
+ jh = next_jh;
+ next_jh = jh->b_cpnext;
+ if (!destroy)
+ ret = __try_to_free_cp_buf(jh);
+ else
+ ret = __jbd2_journal_remove_checkpoint(jh) + 1;
+ if (!ret)
+ return 0;
+ if (ret == 2)
+ return 1;
+ /*
+ * This function only frees up some memory
+ * if possible so we dont have an obligation
+ * to finish processing. Bail out if preemption
+ * requested:
+ */
+ if (need_resched())
+ return 0;
+ } while (jh != last_jh);
+
+ return 0;
+}
+
+/*
+ * journal_clean_checkpoint_list
+ *
+ * Find all the written-back checkpoint buffers in the journal and release them.
+ * If 'destroy' is set, release all buffers unconditionally.
+ *
+ * Called with j_list_lock held.
+ */
+void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy)
+{
+ transaction_t *transaction, *last_transaction, *next_transaction;
+ int ret;
+
+ transaction = journal->j_checkpoint_transactions;
+ if (!transaction)
+ return;
+
+ last_transaction = transaction->t_cpprev;
+ next_transaction = transaction;
+ do {
+ transaction = next_transaction;
+ next_transaction = transaction->t_cpnext;
+ ret = journal_clean_one_cp_list(transaction->t_checkpoint_list,
+ destroy);
+ /*
+ * This function only frees up some memory if possible so we
+ * dont have an obligation to finish processing. Bail out if
+ * preemption requested:
+ */
+ if (need_resched())
+ return;
+ if (ret)
+ continue;
+ /*
+ * It is essential that we are as careful as in the case of
+ * t_checkpoint_list with removing the buffer from the list as
+ * we can possibly see not yet submitted buffers on io_list
+ */
+ ret = journal_clean_one_cp_list(transaction->
+ t_checkpoint_io_list, destroy);
+ if (need_resched())
+ return;
+ /*
+ * Stop scanning if we couldn't free the transaction. This
+ * avoids pointless scanning of transactions which still
+ * weren't checkpointed.
+ */
+ if (!ret)
+ return;
+ } while (transaction != last_transaction);
+}
+
+/*
+ * Remove buffers from all checkpoint lists as journal is aborted and we just
+ * need to free memory
+ */
+void jbd2_journal_destroy_checkpoint(journal_t *journal)
+{
+ /*
+ * We loop because __jbd2_journal_clean_checkpoint_list() may abort
+ * early due to a need of rescheduling.
+ */
+ while (1) {
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions) {
+ spin_unlock(&journal->j_list_lock);
+ break;
+ }
+ __jbd2_journal_clean_checkpoint_list(journal, true);
+ spin_unlock(&journal->j_list_lock);
+ cond_resched();
+ }
+}
+
+/*
+ * journal_remove_checkpoint: called after a buffer has been committed
+ * to disk (either by being write-back flushed to disk, or being
+ * committed to the log).
+ *
+ * We cannot safely clean a transaction out of the log until all of the
+ * buffer updates committed in that transaction have safely been stored
+ * elsewhere on disk. To achieve this, all of the buffers in a
+ * transaction need to be maintained on the transaction's checkpoint
+ * lists until they have been rewritten, at which point this function is
+ * called to remove the buffer from the existing transaction's
+ * checkpoint lists.
+ *
+ * The function returns 1 if it frees the transaction, 0 otherwise.
+ * The function can free jh and bh.
+ *
+ * This function is called with j_list_lock held.
+ */
+int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
+{
+ struct transaction_chp_stats_s *stats;
+ transaction_t *transaction;
+ journal_t *journal;
+ int ret = 0;
+
+ JBUFFER_TRACE(jh, "entry");
+
+ if ((transaction = jh->b_cp_transaction) == NULL) {
+ JBUFFER_TRACE(jh, "not on transaction");
+ goto out;
+ }
+ journal = transaction->t_journal;
+
+ JBUFFER_TRACE(jh, "removing from transaction");
+ __buffer_unlink(jh);
+ jh->b_cp_transaction = NULL;
+ jbd2_journal_put_journal_head(jh);
+
+ if (transaction->t_checkpoint_list != NULL ||
+ transaction->t_checkpoint_io_list != NULL)
+ goto out;
+
+ /*
+ * There is one special case to worry about: if we have just pulled the
+ * buffer off a running or committing transaction's checkpoing list,
+ * then even if the checkpoint list is empty, the transaction obviously
+ * cannot be dropped!
+ *
+ * The locking here around t_state is a bit sleazy.
+ * See the comment at the end of jbd2_journal_commit_transaction().
+ */
+ if (transaction->t_state != T_FINISHED)
+ goto out;
+
+ /* OK, that was the last buffer for the transaction: we can now
+ safely remove this transaction from the log */
+ stats = &transaction->t_chp_stats;
+ if (stats->cs_chp_time)
+ stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
+ jiffies);
+ trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
+ transaction->t_tid, stats);
+
+ __jbd2_journal_drop_transaction(journal, transaction);
+ jbd2_journal_free_transaction(transaction);
+ ret = 1;
+out:
+ return ret;
+}
+
+/*
+ * journal_insert_checkpoint: put a committed buffer onto a checkpoint
+ * list so that we know when it is safe to clean the transaction out of
+ * the log.
+ *
+ * Called with the journal locked.
+ * Called with j_list_lock held.
+ */
+void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
+ transaction_t *transaction)
+{
+ JBUFFER_TRACE(jh, "entry");
+ J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
+ J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
+
+ /* Get reference for checkpointing transaction */
+ jbd2_journal_grab_journal_head(jh2bh(jh));
+ jh->b_cp_transaction = transaction;
+
+ if (!transaction->t_checkpoint_list) {
+ jh->b_cpnext = jh->b_cpprev = jh;
+ } else {
+ jh->b_cpnext = transaction->t_checkpoint_list;
+ jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
+ jh->b_cpprev->b_cpnext = jh;
+ jh->b_cpnext->b_cpprev = jh;
+ }
+ transaction->t_checkpoint_list = jh;
+}
+
+/*
+ * We've finished with this transaction structure: adios...
+ *
+ * The transaction must have no links except for the checkpoint by this
+ * point.
+ *
+ * Called with the journal locked.
+ * Called with j_list_lock held.
+ */
+
+void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
+{
+ assert_spin_locked(&journal->j_list_lock);
+ if (transaction->t_cpnext) {
+ transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
+ transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
+ if (journal->j_checkpoint_transactions == transaction)
+ journal->j_checkpoint_transactions =
+ transaction->t_cpnext;
+ if (journal->j_checkpoint_transactions == transaction)
+ journal->j_checkpoint_transactions = NULL;
+ }
+
+ J_ASSERT(transaction->t_state == T_FINISHED);
+ J_ASSERT(transaction->t_buffers == NULL);
+ J_ASSERT(transaction->t_forget == NULL);
+ J_ASSERT(transaction->t_shadow_list == NULL);
+ J_ASSERT(transaction->t_checkpoint_list == NULL);
+ J_ASSERT(transaction->t_checkpoint_io_list == NULL);
+ J_ASSERT(atomic_read(&transaction->t_updates) == 0);
+ J_ASSERT(journal->j_committing_transaction != transaction);
+ J_ASSERT(journal->j_running_transaction != transaction);
+
+ trace_jbd2_drop_transaction(journal, transaction);
+
+ jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
+}
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
new file mode 100644
index 0000000..150cc03
--- /dev/null
+++ b/fs/jbd2/commit.c
@@ -0,0 +1,1129 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/commit.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
+ *
+ * Copyright 1998 Red Hat corp --- All Rights Reserved
+ *
+ * Journal commit routines for the generic filesystem journaling code;
+ * part of the ext2fs journaling system.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/jiffies.h>
+#include <linux/crc32.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/bitops.h>
+#include <trace/events/jbd2.h>
+
+/*
+ * IO end handler for temporary buffer_heads handling writes to the journal.
+ */
+static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
+{
+ struct buffer_head *orig_bh = bh->b_private;
+
+ BUFFER_TRACE(bh, "");
+ if (uptodate)
+ set_buffer_uptodate(bh);
+ else
+ clear_buffer_uptodate(bh);
+ if (orig_bh) {
+ clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
+ smp_mb__after_atomic();
+ wake_up_bit(&orig_bh->b_state, BH_Shadow);
+ }
+ unlock_buffer(bh);
+}
+
+/*
+ * When an ext4 file is truncated, it is possible that some pages are not
+ * successfully freed, because they are attached to a committing transaction.
+ * After the transaction commits, these pages are left on the LRU, with no
+ * ->mapping, and with attached buffers. These pages are trivially reclaimable
+ * by the VM, but their apparent absence upsets the VM accounting, and it makes
+ * the numbers in /proc/meminfo look odd.
+ *
+ * So here, we have a buffer which has just come off the forget list. Look to
+ * see if we can strip all buffers from the backing page.
+ *
+ * Called under lock_journal(), and possibly under journal_datalist_lock. The
+ * caller provided us with a ref against the buffer, and we drop that here.
+ */
+static void release_buffer_page(struct buffer_head *bh)
+{
+ struct page *page;
+
+ if (buffer_dirty(bh))
+ goto nope;
+ if (atomic_read(&bh->b_count) != 1)
+ goto nope;
+ page = bh->b_page;
+ if (!page)
+ goto nope;
+ if (page->mapping)
+ goto nope;
+
+ /* OK, it's a truncated page */
+ if (!trylock_page(page))
+ goto nope;
+
+ get_page(page);
+ __brelse(bh);
+ try_to_free_buffers(page);
+ unlock_page(page);
+ put_page(page);
+ return;
+
+nope:
+ __brelse(bh);
+}
+
+static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
+{
+ struct commit_header *h;
+ __u32 csum;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ h = (struct commit_header *)(bh->b_data);
+ h->h_chksum_type = 0;
+ h->h_chksum_size = 0;
+ h->h_chksum[0] = 0;
+ csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
+ h->h_chksum[0] = cpu_to_be32(csum);
+}
+
+/*
+ * Done it all: now submit the commit record. We should have
+ * cleaned up our previous buffers by now, so if we are in abort
+ * mode we can now just skip the rest of the journal write
+ * entirely.
+ *
+ * Returns 1 if the journal needs to be aborted or 0 on success
+ */
+static int journal_submit_commit_record(journal_t *journal,
+ transaction_t *commit_transaction,
+ struct buffer_head **cbh,
+ __u32 crc32_sum)
+{
+ struct commit_header *tmp;
+ struct buffer_head *bh;
+ int ret;
+ struct timespec64 now;
+
+ *cbh = NULL;
+
+ if (is_journal_aborted(journal))
+ return 0;
+
+ bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
+ JBD2_COMMIT_BLOCK);
+ if (!bh)
+ return 1;
+
+ tmp = (struct commit_header *)bh->b_data;
+ ktime_get_coarse_real_ts64(&now);
+ tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
+ tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
+
+ if (jbd2_has_feature_checksum(journal)) {
+ tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
+ tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
+ tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
+ }
+ jbd2_commit_block_csum_set(journal, bh);
+
+ BUFFER_TRACE(bh, "submit commit block");
+ lock_buffer(bh);
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ bh->b_end_io = journal_end_buffer_io_sync;
+
+ if (journal->j_flags & JBD2_BARRIER &&
+ !jbd2_has_feature_async_commit(journal))
+ ret = submit_bh(REQ_OP_WRITE,
+ REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
+ else
+ ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
+
+ *cbh = bh;
+ return ret;
+}
+
+/*
+ * This function along with journal_submit_commit_record
+ * allows to write the commit record asynchronously.
+ */
+static int journal_wait_on_commit_record(journal_t *journal,
+ struct buffer_head *bh)
+{
+ int ret = 0;
+
+ clear_buffer_dirty(bh);
+ wait_on_buffer(bh);
+
+ if (unlikely(!buffer_uptodate(bh)))
+ ret = -EIO;
+ put_bh(bh); /* One for getblk() */
+
+ return ret;
+}
+
+/*
+ * write the filemap data using writepage() address_space_operations.
+ * We don't do block allocation here even for delalloc. We don't
+ * use writepages() because with dealyed allocation we may be doing
+ * block allocation in writepages().
+ */
+static int journal_submit_inode_data_buffers(struct address_space *mapping)
+{
+ int ret;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = mapping->nrpages * 2,
+ .range_start = 0,
+ .range_end = i_size_read(mapping->host),
+ };
+
+ ret = generic_writepages(mapping, &wbc);
+ return ret;
+}
+
+/*
+ * Submit all the data buffers of inode associated with the transaction to
+ * disk.
+ *
+ * We are in a committing transaction. Therefore no new inode can be added to
+ * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
+ * operate on from being released while we write out pages.
+ */
+static int journal_submit_data_buffers(journal_t *journal,
+ transaction_t *commit_transaction)
+{
+ struct jbd2_inode *jinode;
+ int err, ret = 0;
+ struct address_space *mapping;
+
+ spin_lock(&journal->j_list_lock);
+ list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+ if (!(jinode->i_flags & JI_WRITE_DATA))
+ continue;
+ mapping = jinode->i_vfs_inode->i_mapping;
+ jinode->i_flags |= JI_COMMIT_RUNNING;
+ spin_unlock(&journal->j_list_lock);
+ /*
+ * submit the inode data buffers. We use writepage
+ * instead of writepages. Because writepages can do
+ * block allocation with delalloc. We need to write
+ * only allocated blocks here.
+ */
+ trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
+ err = journal_submit_inode_data_buffers(mapping);
+ if (!ret)
+ ret = err;
+ spin_lock(&journal->j_list_lock);
+ J_ASSERT(jinode->i_transaction == commit_transaction);
+ jinode->i_flags &= ~JI_COMMIT_RUNNING;
+ smp_mb();
+ wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+ }
+ spin_unlock(&journal->j_list_lock);
+ return ret;
+}
+
+/*
+ * Wait for data submitted for writeout, refile inodes to proper
+ * transaction if needed.
+ *
+ */
+static int journal_finish_inode_data_buffers(journal_t *journal,
+ transaction_t *commit_transaction)
+{
+ struct jbd2_inode *jinode, *next_i;
+ int err, ret = 0;
+
+ /* For locking, see the comment in journal_submit_data_buffers() */
+ spin_lock(&journal->j_list_lock);
+ list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+ if (!(jinode->i_flags & JI_WAIT_DATA))
+ continue;
+ jinode->i_flags |= JI_COMMIT_RUNNING;
+ spin_unlock(&journal->j_list_lock);
+ err = filemap_fdatawait_keep_errors(
+ jinode->i_vfs_inode->i_mapping);
+ if (!ret)
+ ret = err;
+ spin_lock(&journal->j_list_lock);
+ jinode->i_flags &= ~JI_COMMIT_RUNNING;
+ smp_mb();
+ wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+ }
+
+ /* Now refile inode to proper lists */
+ list_for_each_entry_safe(jinode, next_i,
+ &commit_transaction->t_inode_list, i_list) {
+ list_del(&jinode->i_list);
+ if (jinode->i_next_transaction) {
+ jinode->i_transaction = jinode->i_next_transaction;
+ jinode->i_next_transaction = NULL;
+ list_add(&jinode->i_list,
+ &jinode->i_transaction->t_inode_list);
+ } else {
+ jinode->i_transaction = NULL;
+ }
+ }
+ spin_unlock(&journal->j_list_lock);
+
+ return ret;
+}
+
+static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
+{
+ struct page *page = bh->b_page;
+ char *addr;
+ __u32 checksum;
+
+ addr = kmap_atomic(page);
+ checksum = crc32_be(crc32_sum,
+ (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
+ kunmap_atomic(addr);
+
+ return checksum;
+}
+
+static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
+ unsigned long long block)
+{
+ tag->t_blocknr = cpu_to_be32(block & (u32)~0);
+ if (jbd2_has_feature_64bit(j))
+ tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
+}
+
+static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
+ struct buffer_head *bh, __u32 sequence)
+{
+ journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
+ struct page *page = bh->b_page;
+ __u8 *addr;
+ __u32 csum32;
+ __be32 seq;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ seq = cpu_to_be32(sequence);
+ addr = kmap_atomic(page);
+ csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
+ csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
+ bh->b_size);
+ kunmap_atomic(addr);
+
+ if (jbd2_has_feature_csum3(j))
+ tag3->t_checksum = cpu_to_be32(csum32);
+ else
+ tag->t_checksum = cpu_to_be16(csum32);
+}
+/*
+ * jbd2_journal_commit_transaction
+ *
+ * The primary function for committing a transaction to the log. This
+ * function is called by the journal thread to begin a complete commit.
+ */
+void jbd2_journal_commit_transaction(journal_t *journal)
+{
+ struct transaction_stats_s stats;
+ transaction_t *commit_transaction;
+ struct journal_head *jh;
+ struct buffer_head *descriptor;
+ struct buffer_head **wbuf = journal->j_wbuf;
+ int bufs;
+ int flags;
+ int err;
+ unsigned long long blocknr;
+ ktime_t start_time;
+ u64 commit_time;
+ char *tagp = NULL;
+ journal_block_tag_t *tag = NULL;
+ int space_left = 0;
+ int first_tag = 0;
+ int tag_flag;
+ int i;
+ int tag_bytes = journal_tag_bytes(journal);
+ struct buffer_head *cbh = NULL; /* For transactional checksums */
+ __u32 crc32_sum = ~0;
+ struct blk_plug plug;
+ /* Tail of the journal */
+ unsigned long first_block;
+ tid_t first_tid;
+ int update_tail;
+ int csum_size = 0;
+ LIST_HEAD(io_bufs);
+ LIST_HEAD(log_bufs);
+
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
+
+ /*
+ * First job: lock down the current transaction and wait for
+ * all outstanding updates to complete.
+ */
+
+ /* Do we need to erase the effects of a prior jbd2_journal_flush? */
+ if (journal->j_flags & JBD2_FLUSHED) {
+ jbd_debug(3, "super block updated\n");
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ /*
+ * We hold j_checkpoint_mutex so tail cannot change under us.
+ * We don't need any special data guarantees for writing sb
+ * since journal is empty and it is ok for write to be
+ * flushed only with transaction commit.
+ */
+ jbd2_journal_update_sb_log_tail(journal,
+ journal->j_tail_sequence,
+ journal->j_tail,
+ REQ_SYNC);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ } else {
+ jbd_debug(3, "superblock not updated\n");
+ }
+
+ J_ASSERT(journal->j_running_transaction != NULL);
+ J_ASSERT(journal->j_committing_transaction == NULL);
+
+ commit_transaction = journal->j_running_transaction;
+
+ trace_jbd2_start_commit(journal, commit_transaction);
+ jbd_debug(1, "JBD2: starting commit of transaction %d\n",
+ commit_transaction->t_tid);
+
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(commit_transaction->t_state == T_RUNNING);
+ commit_transaction->t_state = T_LOCKED;
+
+ trace_jbd2_commit_locking(journal, commit_transaction);
+ stats.run.rs_wait = commit_transaction->t_max_wait;
+ stats.run.rs_request_delay = 0;
+ stats.run.rs_locked = jiffies;
+ if (commit_transaction->t_requested)
+ stats.run.rs_request_delay =
+ jbd2_time_diff(commit_transaction->t_requested,
+ stats.run.rs_locked);
+ stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
+ stats.run.rs_locked);
+
+ spin_lock(&commit_transaction->t_handle_lock);
+ while (atomic_read(&commit_transaction->t_updates)) {
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&journal->j_wait_updates, &wait,
+ TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&commit_transaction->t_updates)) {
+ spin_unlock(&commit_transaction->t_handle_lock);
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ write_lock(&journal->j_state_lock);
+ spin_lock(&commit_transaction->t_handle_lock);
+ }
+ finish_wait(&journal->j_wait_updates, &wait);
+ }
+ spin_unlock(&commit_transaction->t_handle_lock);
+
+ J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
+ journal->j_max_transaction_buffers);
+
+ /*
+ * First thing we are allowed to do is to discard any remaining
+ * BJ_Reserved buffers. Note, it is _not_ permissible to assume
+ * that there are no such buffers: if a large filesystem
+ * operation like a truncate needs to split itself over multiple
+ * transactions, then it may try to do a jbd2_journal_restart() while
+ * there are still BJ_Reserved buffers outstanding. These must
+ * be released cleanly from the current transaction.
+ *
+ * In this case, the filesystem must still reserve write access
+ * again before modifying the buffer in the new transaction, but
+ * we do not require it to remember exactly which old buffers it
+ * has reserved. This is consistent with the existing behaviour
+ * that multiple jbd2_journal_get_write_access() calls to the same
+ * buffer are perfectly permissible.
+ */
+ while (commit_transaction->t_reserved_list) {
+ jh = commit_transaction->t_reserved_list;
+ JBUFFER_TRACE(jh, "reserved, unused: refile");
+ /*
+ * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
+ * leave undo-committed data.
+ */
+ if (jh->b_committed_data) {
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd_lock_bh_state(bh);
+ jbd2_free(jh->b_committed_data, bh->b_size);
+ jh->b_committed_data = NULL;
+ jbd_unlock_bh_state(bh);
+ }
+ jbd2_journal_refile_buffer(journal, jh);
+ }
+
+ /*
+ * Now try to drop any written-back buffers from the journal's
+ * checkpoint lists. We do this *before* commit because it potentially
+ * frees some memory
+ */
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_clean_checkpoint_list(journal, false);
+ spin_unlock(&journal->j_list_lock);
+
+ jbd_debug(3, "JBD2: commit phase 1\n");
+
+ /*
+ * Clear revoked flag to reflect there is no revoked buffers
+ * in the next transaction which is going to be started.
+ */
+ jbd2_clear_buffer_revoked_flags(journal);
+
+ /*
+ * Switch to a new revoke table.
+ */
+ jbd2_journal_switch_revoke_table(journal);
+
+ /*
+ * Reserved credits cannot be claimed anymore, free them
+ */
+ atomic_sub(atomic_read(&journal->j_reserved_credits),
+ &commit_transaction->t_outstanding_credits);
+
+ trace_jbd2_commit_flushing(journal, commit_transaction);
+ stats.run.rs_flushing = jiffies;
+ stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
+ stats.run.rs_flushing);
+
+ commit_transaction->t_state = T_FLUSH;
+ journal->j_committing_transaction = commit_transaction;
+ journal->j_running_transaction = NULL;
+ start_time = ktime_get();
+ commit_transaction->t_log_start = journal->j_head;
+ wake_up(&journal->j_wait_transaction_locked);
+ write_unlock(&journal->j_state_lock);
+
+ jbd_debug(3, "JBD2: commit phase 2a\n");
+
+ /*
+ * Now start flushing things to disk, in the order they appear
+ * on the transaction lists. Data blocks go first.
+ */
+ err = journal_submit_data_buffers(journal, commit_transaction);
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ blk_start_plug(&plug);
+ jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
+
+ jbd_debug(3, "JBD2: commit phase 2b\n");
+
+ /*
+ * Way to go: we have now written out all of the data for a
+ * transaction! Now comes the tricky part: we need to write out
+ * metadata. Loop over the transaction's entire buffer list:
+ */
+ write_lock(&journal->j_state_lock);
+ commit_transaction->t_state = T_COMMIT;
+ write_unlock(&journal->j_state_lock);
+
+ trace_jbd2_commit_logging(journal, commit_transaction);
+ stats.run.rs_logging = jiffies;
+ stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
+ stats.run.rs_logging);
+ stats.run.rs_blocks =
+ atomic_read(&commit_transaction->t_outstanding_credits);
+ stats.run.rs_blocks_logged = 0;
+
+ J_ASSERT(commit_transaction->t_nr_buffers <=
+ atomic_read(&commit_transaction->t_outstanding_credits));
+
+ err = 0;
+ bufs = 0;
+ descriptor = NULL;
+ while (commit_transaction->t_buffers) {
+
+ /* Find the next buffer to be journaled... */
+
+ jh = commit_transaction->t_buffers;
+
+ /* If we're in abort mode, we just un-journal the buffer and
+ release it. */
+
+ if (is_journal_aborted(journal)) {
+ clear_buffer_jbddirty(jh2bh(jh));
+ JBUFFER_TRACE(jh, "journal is aborting: refile");
+ jbd2_buffer_abort_trigger(jh,
+ jh->b_frozen_data ?
+ jh->b_frozen_triggers :
+ jh->b_triggers);
+ jbd2_journal_refile_buffer(journal, jh);
+ /* If that was the last one, we need to clean up
+ * any descriptor buffers which may have been
+ * already allocated, even if we are now
+ * aborting. */
+ if (!commit_transaction->t_buffers)
+ goto start_journal_io;
+ continue;
+ }
+
+ /* Make sure we have a descriptor block in which to
+ record the metadata buffer. */
+
+ if (!descriptor) {
+ J_ASSERT (bufs == 0);
+
+ jbd_debug(4, "JBD2: get descriptor\n");
+
+ descriptor = jbd2_journal_get_descriptor_buffer(
+ commit_transaction,
+ JBD2_DESCRIPTOR_BLOCK);
+ if (!descriptor) {
+ jbd2_journal_abort(journal, -EIO);
+ continue;
+ }
+
+ jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
+ (unsigned long long)descriptor->b_blocknr,
+ descriptor->b_data);
+ tagp = &descriptor->b_data[sizeof(journal_header_t)];
+ space_left = descriptor->b_size -
+ sizeof(journal_header_t);
+ first_tag = 1;
+ set_buffer_jwrite(descriptor);
+ set_buffer_dirty(descriptor);
+ wbuf[bufs++] = descriptor;
+
+ /* Record it so that we can wait for IO
+ completion later */
+ BUFFER_TRACE(descriptor, "ph3: file as descriptor");
+ jbd2_file_log_bh(&log_bufs, descriptor);
+ }
+
+ /* Where is the buffer to be written? */
+
+ err = jbd2_journal_next_log_block(journal, &blocknr);
+ /* If the block mapping failed, just abandon the buffer
+ and repeat this loop: we'll fall into the
+ refile-on-abort condition above. */
+ if (err) {
+ jbd2_journal_abort(journal, err);
+ continue;
+ }
+
+ /*
+ * start_this_handle() uses t_outstanding_credits to determine
+ * the free space in the log, but this counter is changed
+ * by jbd2_journal_next_log_block() also.
+ */
+ atomic_dec(&commit_transaction->t_outstanding_credits);
+
+ /* Bump b_count to prevent truncate from stumbling over
+ the shadowed buffer! @@@ This can go if we ever get
+ rid of the shadow pairing of buffers. */
+ atomic_inc(&jh2bh(jh)->b_count);
+
+ /*
+ * Make a temporary IO buffer with which to write it out
+ * (this will requeue the metadata buffer to BJ_Shadow).
+ */
+ set_bit(BH_JWrite, &jh2bh(jh)->b_state);
+ JBUFFER_TRACE(jh, "ph3: write metadata");
+ flags = jbd2_journal_write_metadata_buffer(commit_transaction,
+ jh, &wbuf[bufs], blocknr);
+ if (flags < 0) {
+ jbd2_journal_abort(journal, flags);
+ continue;
+ }
+ jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
+
+ /* Record the new block's tag in the current descriptor
+ buffer */
+
+ tag_flag = 0;
+ if (flags & 1)
+ tag_flag |= JBD2_FLAG_ESCAPE;
+ if (!first_tag)
+ tag_flag |= JBD2_FLAG_SAME_UUID;
+
+ tag = (journal_block_tag_t *) tagp;
+ write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
+ tag->t_flags = cpu_to_be16(tag_flag);
+ jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
+ commit_transaction->t_tid);
+ tagp += tag_bytes;
+ space_left -= tag_bytes;
+ bufs++;
+
+ if (first_tag) {
+ memcpy (tagp, journal->j_uuid, 16);
+ tagp += 16;
+ space_left -= 16;
+ first_tag = 0;
+ }
+
+ /* If there's no more to do, or if the descriptor is full,
+ let the IO rip! */
+
+ if (bufs == journal->j_wbufsize ||
+ commit_transaction->t_buffers == NULL ||
+ space_left < tag_bytes + 16 + csum_size) {
+
+ jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
+
+ /* Write an end-of-descriptor marker before
+ submitting the IOs. "tag" still points to
+ the last tag we set up. */
+
+ tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
+
+ jbd2_descriptor_block_csum_set(journal, descriptor);
+start_journal_io:
+ for (i = 0; i < bufs; i++) {
+ struct buffer_head *bh = wbuf[i];
+ /*
+ * Compute checksum.
+ */
+ if (jbd2_has_feature_checksum(journal)) {
+ crc32_sum =
+ jbd2_checksum_data(crc32_sum, bh);
+ }
+
+ lock_buffer(bh);
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ bh->b_end_io = journal_end_buffer_io_sync;
+ submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
+ }
+ cond_resched();
+ stats.run.rs_blocks_logged += bufs;
+
+ /* Force a new descriptor to be generated next
+ time round the loop. */
+ descriptor = NULL;
+ bufs = 0;
+ }
+ }
+
+ err = journal_finish_inode_data_buffers(journal, commit_transaction);
+ if (err) {
+ printk(KERN_WARNING
+ "JBD2: Detected IO errors while flushing file data "
+ "on %s\n", journal->j_devname);
+ if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
+ jbd2_journal_abort(journal, err);
+ err = 0;
+ }
+
+ /*
+ * Get current oldest transaction in the log before we issue flush
+ * to the filesystem device. After the flush we can be sure that
+ * blocks of all older transactions are checkpointed to persistent
+ * storage and we will be safe to update journal start in the
+ * superblock with the numbers we get here.
+ */
+ update_tail =
+ jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
+
+ write_lock(&journal->j_state_lock);
+ if (update_tail) {
+ long freed = first_block - journal->j_tail;
+
+ if (first_block < journal->j_tail)
+ freed += journal->j_last - journal->j_first;
+ /* Update tail only if we free significant amount of space */
+ if (freed < journal->j_maxlen / 4)
+ update_tail = 0;
+ }
+ J_ASSERT(commit_transaction->t_state == T_COMMIT);
+ commit_transaction->t_state = T_COMMIT_DFLUSH;
+ write_unlock(&journal->j_state_lock);
+
+ /*
+ * If the journal is not located on the file system device,
+ * then we must flush the file system device before we issue
+ * the commit record
+ */
+ if (commit_transaction->t_need_data_flush &&
+ (journal->j_fs_dev != journal->j_dev) &&
+ (journal->j_flags & JBD2_BARRIER))
+ blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
+
+ /* Done it all: now write the commit record asynchronously. */
+ if (jbd2_has_feature_async_commit(journal)) {
+ err = journal_submit_commit_record(journal, commit_transaction,
+ &cbh, crc32_sum);
+ if (err)
+ __jbd2_journal_abort_hard(journal);
+ }
+
+ blk_finish_plug(&plug);
+
+ /* Lo and behold: we have just managed to send a transaction to
+ the log. Before we can commit it, wait for the IO so far to
+ complete. Control buffers being written are on the
+ transaction's t_log_list queue, and metadata buffers are on
+ the io_bufs list.
+
+ Wait for the buffers in reverse order. That way we are
+ less likely to be woken up until all IOs have completed, and
+ so we incur less scheduling load.
+ */
+
+ jbd_debug(3, "JBD2: commit phase 3\n");
+
+ while (!list_empty(&io_bufs)) {
+ struct buffer_head *bh = list_entry(io_bufs.prev,
+ struct buffer_head,
+ b_assoc_buffers);
+
+ wait_on_buffer(bh);
+ cond_resched();
+
+ if (unlikely(!buffer_uptodate(bh)))
+ err = -EIO;
+ jbd2_unfile_log_bh(bh);
+
+ /*
+ * The list contains temporary buffer heads created by
+ * jbd2_journal_write_metadata_buffer().
+ */
+ BUFFER_TRACE(bh, "dumping temporary bh");
+ __brelse(bh);
+ J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
+ free_buffer_head(bh);
+
+ /* We also have to refile the corresponding shadowed buffer */
+ jh = commit_transaction->t_shadow_list->b_tprev;
+ bh = jh2bh(jh);
+ clear_buffer_jwrite(bh);
+ J_ASSERT_BH(bh, buffer_jbddirty(bh));
+ J_ASSERT_BH(bh, !buffer_shadow(bh));
+
+ /* The metadata is now released for reuse, but we need
+ to remember it against this transaction so that when
+ we finally commit, we can do any checkpointing
+ required. */
+ JBUFFER_TRACE(jh, "file as BJ_Forget");
+ jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
+ JBUFFER_TRACE(jh, "brelse shadowed buffer");
+ __brelse(bh);
+ }
+
+ J_ASSERT (commit_transaction->t_shadow_list == NULL);
+
+ jbd_debug(3, "JBD2: commit phase 4\n");
+
+ /* Here we wait for the revoke record and descriptor record buffers */
+ while (!list_empty(&log_bufs)) {
+ struct buffer_head *bh;
+
+ bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
+ wait_on_buffer(bh);
+ cond_resched();
+
+ if (unlikely(!buffer_uptodate(bh)))
+ err = -EIO;
+
+ BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
+ clear_buffer_jwrite(bh);
+ jbd2_unfile_log_bh(bh);
+ __brelse(bh); /* One for getblk */
+ /* AKPM: bforget here */
+ }
+
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ jbd_debug(3, "JBD2: commit phase 5\n");
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
+ commit_transaction->t_state = T_COMMIT_JFLUSH;
+ write_unlock(&journal->j_state_lock);
+
+ if (!jbd2_has_feature_async_commit(journal)) {
+ err = journal_submit_commit_record(journal, commit_transaction,
+ &cbh, crc32_sum);
+ if (err)
+ __jbd2_journal_abort_hard(journal);
+ }
+ if (cbh)
+ err = journal_wait_on_commit_record(journal, cbh);
+ if (jbd2_has_feature_async_commit(journal) &&
+ journal->j_flags & JBD2_BARRIER) {
+ blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
+ }
+
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ /*
+ * Now disk caches for filesystem device are flushed so we are safe to
+ * erase checkpointed transactions from the log by updating journal
+ * superblock.
+ */
+ if (update_tail)
+ jbd2_update_log_tail(journal, first_tid, first_block);
+
+ /* End of a transaction! Finally, we can do checkpoint
+ processing: any buffers committed as a result of this
+ transaction can be removed from any checkpoint list it was on
+ before. */
+
+ jbd_debug(3, "JBD2: commit phase 6\n");
+
+ J_ASSERT(list_empty(&commit_transaction->t_inode_list));
+ J_ASSERT(commit_transaction->t_buffers == NULL);
+ J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
+ J_ASSERT(commit_transaction->t_shadow_list == NULL);
+
+restart_loop:
+ /*
+ * As there are other places (journal_unmap_buffer()) adding buffers
+ * to this list we have to be careful and hold the j_list_lock.
+ */
+ spin_lock(&journal->j_list_lock);
+ while (commit_transaction->t_forget) {
+ transaction_t *cp_transaction;
+ struct buffer_head *bh;
+ int try_to_free = 0;
+
+ jh = commit_transaction->t_forget;
+ spin_unlock(&journal->j_list_lock);
+ bh = jh2bh(jh);
+ /*
+ * Get a reference so that bh cannot be freed before we are
+ * done with it.
+ */
+ get_bh(bh);
+ jbd_lock_bh_state(bh);
+ J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
+
+ /*
+ * If there is undo-protected committed data against
+ * this buffer, then we can remove it now. If it is a
+ * buffer needing such protection, the old frozen_data
+ * field now points to a committed version of the
+ * buffer, so rotate that field to the new committed
+ * data.
+ *
+ * Otherwise, we can just throw away the frozen data now.
+ *
+ * We also know that the frozen data has already fired
+ * its triggers if they exist, so we can clear that too.
+ */
+ if (jh->b_committed_data) {
+ jbd2_free(jh->b_committed_data, bh->b_size);
+ jh->b_committed_data = NULL;
+ if (jh->b_frozen_data) {
+ jh->b_committed_data = jh->b_frozen_data;
+ jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
+ }
+ } else if (jh->b_frozen_data) {
+ jbd2_free(jh->b_frozen_data, bh->b_size);
+ jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
+ }
+
+ spin_lock(&journal->j_list_lock);
+ cp_transaction = jh->b_cp_transaction;
+ if (cp_transaction) {
+ JBUFFER_TRACE(jh, "remove from old cp transaction");
+ cp_transaction->t_chp_stats.cs_dropped++;
+ __jbd2_journal_remove_checkpoint(jh);
+ }
+
+ /* Only re-checkpoint the buffer_head if it is marked
+ * dirty. If the buffer was added to the BJ_Forget list
+ * by jbd2_journal_forget, it may no longer be dirty and
+ * there's no point in keeping a checkpoint record for
+ * it. */
+
+ /*
+ * A buffer which has been freed while still being journaled by
+ * a previous transaction.
+ */
+ if (buffer_freed(bh)) {
+ /*
+ * If the running transaction is the one containing
+ * "add to orphan" operation (b_next_transaction !=
+ * NULL), we have to wait for that transaction to
+ * commit before we can really get rid of the buffer.
+ * So just clear b_modified to not confuse transaction
+ * credit accounting and refile the buffer to
+ * BJ_Forget of the running transaction. If the just
+ * committed transaction contains "add to orphan"
+ * operation, we can completely invalidate the buffer
+ * now. We are rather through in that since the
+ * buffer may be still accessible when blocksize <
+ * pagesize and it is attached to the last partial
+ * page.
+ */
+ jh->b_modified = 0;
+ if (!jh->b_next_transaction) {
+ clear_buffer_freed(bh);
+ clear_buffer_jbddirty(bh);
+ clear_buffer_mapped(bh);
+ clear_buffer_new(bh);
+ clear_buffer_req(bh);
+ bh->b_bdev = NULL;
+ }
+ }
+
+ if (buffer_jbddirty(bh)) {
+ JBUFFER_TRACE(jh, "add to new checkpointing trans");
+ __jbd2_journal_insert_checkpoint(jh, commit_transaction);
+ if (is_journal_aborted(journal))
+ clear_buffer_jbddirty(bh);
+ } else {
+ J_ASSERT_BH(bh, !buffer_dirty(bh));
+ /*
+ * The buffer on BJ_Forget list and not jbddirty means
+ * it has been freed by this transaction and hence it
+ * could not have been reallocated until this
+ * transaction has committed. *BUT* it could be
+ * reallocated once we have written all the data to
+ * disk and before we process the buffer on BJ_Forget
+ * list.
+ */
+ if (!jh->b_next_transaction)
+ try_to_free = 1;
+ }
+ JBUFFER_TRACE(jh, "refile or unfile buffer");
+ __jbd2_journal_refile_buffer(jh);
+ jbd_unlock_bh_state(bh);
+ if (try_to_free)
+ release_buffer_page(bh); /* Drops bh reference */
+ else
+ __brelse(bh);
+ cond_resched_lock(&journal->j_list_lock);
+ }
+ spin_unlock(&journal->j_list_lock);
+ /*
+ * This is a bit sleazy. We use j_list_lock to protect transition
+ * of a transaction into T_FINISHED state and calling
+ * __jbd2_journal_drop_transaction(). Otherwise we could race with
+ * other checkpointing code processing the transaction...
+ */
+ write_lock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ /*
+ * Now recheck if some buffers did not get attached to the transaction
+ * while the lock was dropped...
+ */
+ if (commit_transaction->t_forget) {
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ goto restart_loop;
+ }
+
+ /* Add the transaction to the checkpoint list
+ * __journal_remove_checkpoint() can not destroy transaction
+ * under us because it is not marked as T_FINISHED yet */
+ if (journal->j_checkpoint_transactions == NULL) {
+ journal->j_checkpoint_transactions = commit_transaction;
+ commit_transaction->t_cpnext = commit_transaction;
+ commit_transaction->t_cpprev = commit_transaction;
+ } else {
+ commit_transaction->t_cpnext =
+ journal->j_checkpoint_transactions;
+ commit_transaction->t_cpprev =
+ commit_transaction->t_cpnext->t_cpprev;
+ commit_transaction->t_cpnext->t_cpprev =
+ commit_transaction;
+ commit_transaction->t_cpprev->t_cpnext =
+ commit_transaction;
+ }
+ spin_unlock(&journal->j_list_lock);
+
+ /* Done with this transaction! */
+
+ jbd_debug(3, "JBD2: commit phase 7\n");
+
+ J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
+
+ commit_transaction->t_start = jiffies;
+ stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
+ commit_transaction->t_start);
+
+ /*
+ * File the transaction statistics
+ */
+ stats.ts_tid = commit_transaction->t_tid;
+ stats.run.rs_handle_count =
+ atomic_read(&commit_transaction->t_handle_count);
+ trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
+ commit_transaction->t_tid, &stats.run);
+ stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
+
+ commit_transaction->t_state = T_COMMIT_CALLBACK;
+ J_ASSERT(commit_transaction == journal->j_committing_transaction);
+ journal->j_commit_sequence = commit_transaction->t_tid;
+ journal->j_committing_transaction = NULL;
+ commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+
+ /*
+ * weight the commit time higher than the average time so we don't
+ * react too strongly to vast changes in the commit time
+ */
+ if (likely(journal->j_average_commit_time))
+ journal->j_average_commit_time = (commit_time +
+ journal->j_average_commit_time*3) / 4;
+ else
+ journal->j_average_commit_time = commit_time;
+
+ write_unlock(&journal->j_state_lock);
+
+ if (journal->j_commit_callback)
+ journal->j_commit_callback(journal, commit_transaction);
+
+ trace_jbd2_end_commit(journal, commit_transaction);
+ jbd_debug(1, "JBD2: commit %d complete, head %d\n",
+ journal->j_commit_sequence, journal->j_tail_sequence);
+
+ write_lock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ commit_transaction->t_state = T_FINISHED;
+ /* Check if the transaction can be dropped now that we are finished */
+ if (commit_transaction->t_checkpoint_list == NULL &&
+ commit_transaction->t_checkpoint_io_list == NULL) {
+ __jbd2_journal_drop_transaction(journal, commit_transaction);
+ jbd2_journal_free_transaction(commit_transaction);
+ }
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_done_commit);
+
+ /*
+ * Calculate overall stats
+ */
+ spin_lock(&journal->j_history_lock);
+ journal->j_stats.ts_tid++;
+ journal->j_stats.ts_requested += stats.ts_requested;
+ journal->j_stats.run.rs_wait += stats.run.rs_wait;
+ journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
+ journal->j_stats.run.rs_running += stats.run.rs_running;
+ journal->j_stats.run.rs_locked += stats.run.rs_locked;
+ journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
+ journal->j_stats.run.rs_logging += stats.run.rs_logging;
+ journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
+ journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
+ journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
+ spin_unlock(&journal->j_history_lock);
+}
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
new file mode 100644
index 0000000..8ef6b6d
--- /dev/null
+++ b/fs/jbd2/journal.c
@@ -0,0 +1,2727 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/journal.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
+ *
+ * Copyright 1998 Red Hat corp --- All Rights Reserved
+ *
+ * Generic filesystem journal-writing code; part of the ext2fs
+ * journaling system.
+ *
+ * This file manages journals: areas of disk reserved for logging
+ * transactional updates. This includes the kernel journaling thread
+ * which is responsible for scheduling updates to the log.
+ *
+ * We do not actually manage the physical storage of the journal in this
+ * file: that is left to a per-journal policy function, which allows us
+ * to store the journal within a filesystem-specified area for ext2
+ * journaling (ext2 can use a reserved inode for storing the log).
+ */
+
+#include <linux/module.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/freezer.h>
+#include <linux/pagemap.h>
+#include <linux/kthread.h>
+#include <linux/poison.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/math64.h>
+#include <linux/hash.h>
+#include <linux/log2.h>
+#include <linux/vmalloc.h>
+#include <linux/backing-dev.h>
+#include <linux/bitops.h>
+#include <linux/ratelimit.h>
+#include <linux/sched/mm.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/jbd2.h>
+
+#include <linux/uaccess.h>
+#include <asm/page.h>
+
+#ifdef CONFIG_JBD2_DEBUG
+ushort jbd2_journal_enable_debug __read_mostly;
+EXPORT_SYMBOL(jbd2_journal_enable_debug);
+
+module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
+MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
+#endif
+
+EXPORT_SYMBOL(jbd2_journal_extend);
+EXPORT_SYMBOL(jbd2_journal_stop);
+EXPORT_SYMBOL(jbd2_journal_lock_updates);
+EXPORT_SYMBOL(jbd2_journal_unlock_updates);
+EXPORT_SYMBOL(jbd2_journal_get_write_access);
+EXPORT_SYMBOL(jbd2_journal_get_create_access);
+EXPORT_SYMBOL(jbd2_journal_get_undo_access);
+EXPORT_SYMBOL(jbd2_journal_set_triggers);
+EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
+EXPORT_SYMBOL(jbd2_journal_forget);
+#if 0
+EXPORT_SYMBOL(journal_sync_buffer);
+#endif
+EXPORT_SYMBOL(jbd2_journal_flush);
+EXPORT_SYMBOL(jbd2_journal_revoke);
+
+EXPORT_SYMBOL(jbd2_journal_init_dev);
+EXPORT_SYMBOL(jbd2_journal_init_inode);
+EXPORT_SYMBOL(jbd2_journal_check_used_features);
+EXPORT_SYMBOL(jbd2_journal_check_available_features);
+EXPORT_SYMBOL(jbd2_journal_set_features);
+EXPORT_SYMBOL(jbd2_journal_load);
+EXPORT_SYMBOL(jbd2_journal_destroy);
+EXPORT_SYMBOL(jbd2_journal_abort);
+EXPORT_SYMBOL(jbd2_journal_errno);
+EXPORT_SYMBOL(jbd2_journal_ack_err);
+EXPORT_SYMBOL(jbd2_journal_clear_err);
+EXPORT_SYMBOL(jbd2_log_wait_commit);
+EXPORT_SYMBOL(jbd2_log_start_commit);
+EXPORT_SYMBOL(jbd2_journal_start_commit);
+EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
+EXPORT_SYMBOL(jbd2_journal_wipe);
+EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
+EXPORT_SYMBOL(jbd2_journal_invalidatepage);
+EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
+EXPORT_SYMBOL(jbd2_journal_force_commit);
+EXPORT_SYMBOL(jbd2_journal_inode_add_write);
+EXPORT_SYMBOL(jbd2_journal_inode_add_wait);
+EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
+EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
+EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
+EXPORT_SYMBOL(jbd2_inode_cache);
+
+static void __journal_abort_soft (journal_t *journal, int errno);
+static int jbd2_journal_create_slab(size_t slab_size);
+
+#ifdef CONFIG_JBD2_DEBUG
+void __jbd2_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ if (level > jbd2_journal_enable_debug)
+ return;
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ printk(KERN_DEBUG "%s: (%s, %u): %pV", file, func, line, &vaf);
+ va_end(args);
+}
+EXPORT_SYMBOL(__jbd2_debug);
+#endif
+
+/* Checksumming functions */
+static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
+{
+ if (!jbd2_journal_has_csum_v2or3_feature(j))
+ return 1;
+
+ return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
+}
+
+static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
+{
+ __u32 csum;
+ __be32 old_csum;
+
+ old_csum = sb->s_checksum;
+ sb->s_checksum = 0;
+ csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
+ sb->s_checksum = old_csum;
+
+ return cpu_to_be32(csum);
+}
+
+static int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
+{
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return 1;
+
+ return sb->s_checksum == jbd2_superblock_csum(j, sb);
+}
+
+static void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
+{
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ sb->s_checksum = jbd2_superblock_csum(j, sb);
+}
+
+/*
+ * Helper function used to manage commit timeouts
+ */
+
+static void commit_timeout(struct timer_list *t)
+{
+ journal_t *journal = from_timer(journal, t, j_commit_timer);
+
+ wake_up_process(journal->j_task);
+}
+
+/*
+ * kjournald2: The main thread function used to manage a logging device
+ * journal.
+ *
+ * This kernel thread is responsible for two things:
+ *
+ * 1) COMMIT: Every so often we need to commit the current state of the
+ * filesystem to disk. The journal thread is responsible for writing
+ * all of the metadata buffers to disk.
+ *
+ * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
+ * of the data in that part of the log has been rewritten elsewhere on
+ * the disk. Flushing these old buffers to reclaim space in the log is
+ * known as checkpointing, and this thread is responsible for that job.
+ */
+
+static int kjournald2(void *arg)
+{
+ journal_t *journal = arg;
+ transaction_t *transaction;
+
+ /*
+ * Set up an interval timer which can be used to trigger a commit wakeup
+ * after the commit interval expires
+ */
+ timer_setup(&journal->j_commit_timer, commit_timeout, 0);
+
+ set_freezable();
+
+ /* Record that the journal thread is running */
+ journal->j_task = current;
+ wake_up(&journal->j_wait_done_commit);
+
+ /*
+ * Make sure that no allocations from this kernel thread will ever
+ * recurse to the fs layer because we are responsible for the
+ * transaction commit and any fs involvement might get stuck waiting for
+ * the trasn. commit.
+ */
+ memalloc_nofs_save();
+
+ /*
+ * And now, wait forever for commit wakeup events.
+ */
+ write_lock(&journal->j_state_lock);
+
+loop:
+ if (journal->j_flags & JBD2_UNMOUNT)
+ goto end_loop;
+
+ jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
+ journal->j_commit_sequence, journal->j_commit_request);
+
+ if (journal->j_commit_sequence != journal->j_commit_request) {
+ jbd_debug(1, "OK, requests differ\n");
+ write_unlock(&journal->j_state_lock);
+ del_timer_sync(&journal->j_commit_timer);
+ jbd2_journal_commit_transaction(journal);
+ write_lock(&journal->j_state_lock);
+ goto loop;
+ }
+
+ wake_up(&journal->j_wait_done_commit);
+ if (freezing(current)) {
+ /*
+ * The simpler the better. Flushing journal isn't a
+ * good idea, because that depends on threads that may
+ * be already stopped.
+ */
+ jbd_debug(1, "Now suspending kjournald2\n");
+ write_unlock(&journal->j_state_lock);
+ try_to_freeze();
+ write_lock(&journal->j_state_lock);
+ } else {
+ /*
+ * We assume on resume that commits are already there,
+ * so we don't sleep
+ */
+ DEFINE_WAIT(wait);
+ int should_sleep = 1;
+
+ prepare_to_wait(&journal->j_wait_commit, &wait,
+ TASK_INTERRUPTIBLE);
+ if (journal->j_commit_sequence != journal->j_commit_request)
+ should_sleep = 0;
+ transaction = journal->j_running_transaction;
+ if (transaction && time_after_eq(jiffies,
+ transaction->t_expires))
+ should_sleep = 0;
+ if (journal->j_flags & JBD2_UNMOUNT)
+ should_sleep = 0;
+ if (should_sleep) {
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ write_lock(&journal->j_state_lock);
+ }
+ finish_wait(&journal->j_wait_commit, &wait);
+ }
+
+ jbd_debug(1, "kjournald2 wakes\n");
+
+ /*
+ * Were we woken up by a commit wakeup event?
+ */
+ transaction = journal->j_running_transaction;
+ if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
+ journal->j_commit_request = transaction->t_tid;
+ jbd_debug(1, "woke because of timeout\n");
+ }
+ goto loop;
+
+end_loop:
+ del_timer_sync(&journal->j_commit_timer);
+ journal->j_task = NULL;
+ wake_up(&journal->j_wait_done_commit);
+ jbd_debug(1, "Journal thread exiting.\n");
+ write_unlock(&journal->j_state_lock);
+ return 0;
+}
+
+static int jbd2_journal_start_thread(journal_t *journal)
+{
+ struct task_struct *t;
+
+ t = kthread_run(kjournald2, journal, "jbd2/%s",
+ journal->j_devname);
+ if (IS_ERR(t))
+ return PTR_ERR(t);
+
+ wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
+ return 0;
+}
+
+static void journal_kill_thread(journal_t *journal)
+{
+ write_lock(&journal->j_state_lock);
+ journal->j_flags |= JBD2_UNMOUNT;
+
+ while (journal->j_task) {
+ write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_commit);
+ wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
+ write_lock(&journal->j_state_lock);
+ }
+ write_unlock(&journal->j_state_lock);
+}
+
+/*
+ * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
+ *
+ * Writes a metadata buffer to a given disk block. The actual IO is not
+ * performed but a new buffer_head is constructed which labels the data
+ * to be written with the correct destination disk block.
+ *
+ * Any magic-number escaping which needs to be done will cause a
+ * copy-out here. If the buffer happens to start with the
+ * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
+ * magic number is only written to the log for descripter blocks. In
+ * this case, we copy the data and replace the first word with 0, and we
+ * return a result code which indicates that this buffer needs to be
+ * marked as an escaped buffer in the corresponding log descriptor
+ * block. The missing word can then be restored when the block is read
+ * during recovery.
+ *
+ * If the source buffer has already been modified by a new transaction
+ * since we took the last commit snapshot, we use the frozen copy of
+ * that data for IO. If we end up using the existing buffer_head's data
+ * for the write, then we have to make sure nobody modifies it while the
+ * IO is in progress. do_get_write_access() handles this.
+ *
+ * The function returns a pointer to the buffer_head to be used for IO.
+ *
+ *
+ * Return value:
+ * <0: Error
+ * >=0: Finished OK
+ *
+ * On success:
+ * Bit 0 set == escape performed on the data
+ * Bit 1 set == buffer copy-out performed (kfree the data after IO)
+ */
+
+int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
+ struct journal_head *jh_in,
+ struct buffer_head **bh_out,
+ sector_t blocknr)
+{
+ int need_copy_out = 0;
+ int done_copy_out = 0;
+ int do_escape = 0;
+ char *mapped_data;
+ struct buffer_head *new_bh;
+ struct page *new_page;
+ unsigned int new_offset;
+ struct buffer_head *bh_in = jh2bh(jh_in);
+ journal_t *journal = transaction->t_journal;
+
+ /*
+ * The buffer really shouldn't be locked: only the current committing
+ * transaction is allowed to write it, so nobody else is allowed
+ * to do any IO.
+ *
+ * akpm: except if we're journalling data, and write() output is
+ * also part of a shared mapping, and another thread has
+ * decided to launch a writepage() against this buffer.
+ */
+ J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
+
+ new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
+
+ /* keep subsequent assertions sane */
+ atomic_set(&new_bh->b_count, 1);
+
+ jbd_lock_bh_state(bh_in);
+repeat:
+ /*
+ * If a new transaction has already done a buffer copy-out, then
+ * we use that version of the data for the commit.
+ */
+ if (jh_in->b_frozen_data) {
+ done_copy_out = 1;
+ new_page = virt_to_page(jh_in->b_frozen_data);
+ new_offset = offset_in_page(jh_in->b_frozen_data);
+ } else {
+ new_page = jh2bh(jh_in)->b_page;
+ new_offset = offset_in_page(jh2bh(jh_in)->b_data);
+ }
+
+ mapped_data = kmap_atomic(new_page);
+ /*
+ * Fire data frozen trigger if data already wasn't frozen. Do this
+ * before checking for escaping, as the trigger may modify the magic
+ * offset. If a copy-out happens afterwards, it will have the correct
+ * data in the buffer.
+ */
+ if (!done_copy_out)
+ jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
+ jh_in->b_triggers);
+
+ /*
+ * Check for escaping
+ */
+ if (*((__be32 *)(mapped_data + new_offset)) ==
+ cpu_to_be32(JBD2_MAGIC_NUMBER)) {
+ need_copy_out = 1;
+ do_escape = 1;
+ }
+ kunmap_atomic(mapped_data);
+
+ /*
+ * Do we need to do a data copy?
+ */
+ if (need_copy_out && !done_copy_out) {
+ char *tmp;
+
+ jbd_unlock_bh_state(bh_in);
+ tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
+ if (!tmp) {
+ brelse(new_bh);
+ return -ENOMEM;
+ }
+ jbd_lock_bh_state(bh_in);
+ if (jh_in->b_frozen_data) {
+ jbd2_free(tmp, bh_in->b_size);
+ goto repeat;
+ }
+
+ jh_in->b_frozen_data = tmp;
+ mapped_data = kmap_atomic(new_page);
+ memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
+ kunmap_atomic(mapped_data);
+
+ new_page = virt_to_page(tmp);
+ new_offset = offset_in_page(tmp);
+ done_copy_out = 1;
+
+ /*
+ * This isn't strictly necessary, as we're using frozen
+ * data for the escaping, but it keeps consistency with
+ * b_frozen_data usage.
+ */
+ jh_in->b_frozen_triggers = jh_in->b_triggers;
+ }
+
+ /*
+ * Did we need to do an escaping? Now we've done all the
+ * copying, we can finally do so.
+ */
+ if (do_escape) {
+ mapped_data = kmap_atomic(new_page);
+ *((unsigned int *)(mapped_data + new_offset)) = 0;
+ kunmap_atomic(mapped_data);
+ }
+
+ set_bh_page(new_bh, new_page, new_offset);
+ new_bh->b_size = bh_in->b_size;
+ new_bh->b_bdev = journal->j_dev;
+ new_bh->b_blocknr = blocknr;
+ new_bh->b_private = bh_in;
+ set_buffer_mapped(new_bh);
+ set_buffer_dirty(new_bh);
+
+ *bh_out = new_bh;
+
+ /*
+ * The to-be-written buffer needs to get moved to the io queue,
+ * and the original buffer whose contents we are shadowing or
+ * copying is moved to the transaction's shadow queue.
+ */
+ JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
+ spin_unlock(&journal->j_list_lock);
+ set_buffer_shadow(bh_in);
+ jbd_unlock_bh_state(bh_in);
+
+ return do_escape | (done_copy_out << 1);
+}
+
+/*
+ * Allocation code for the journal file. Manage the space left in the
+ * journal, so that we can begin checkpointing when appropriate.
+ */
+
+/*
+ * Called with j_state_lock locked for writing.
+ * Returns true if a transaction commit was started.
+ */
+int __jbd2_log_start_commit(journal_t *journal, tid_t target)
+{
+ /* Return if the txn has already requested to be committed */
+ if (journal->j_commit_request == target)
+ return 0;
+
+ /*
+ * The only transaction we can possibly wait upon is the
+ * currently running transaction (if it exists). Otherwise,
+ * the target tid must be an old one.
+ */
+ if (journal->j_running_transaction &&
+ journal->j_running_transaction->t_tid == target) {
+ /*
+ * We want a new commit: OK, mark the request and wakeup the
+ * commit thread. We do _not_ do the commit ourselves.
+ */
+
+ journal->j_commit_request = target;
+ jbd_debug(1, "JBD2: requesting commit %d/%d\n",
+ journal->j_commit_request,
+ journal->j_commit_sequence);
+ journal->j_running_transaction->t_requested = jiffies;
+ wake_up(&journal->j_wait_commit);
+ return 1;
+ } else if (!tid_geq(journal->j_commit_request, target))
+ /* This should never happen, but if it does, preserve
+ the evidence before kjournald goes into a loop and
+ increments j_commit_sequence beyond all recognition. */
+ WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
+ journal->j_commit_request,
+ journal->j_commit_sequence,
+ target, journal->j_running_transaction ?
+ journal->j_running_transaction->t_tid : 0);
+ return 0;
+}
+
+int jbd2_log_start_commit(journal_t *journal, tid_t tid)
+{
+ int ret;
+
+ write_lock(&journal->j_state_lock);
+ ret = __jbd2_log_start_commit(journal, tid);
+ write_unlock(&journal->j_state_lock);
+ return ret;
+}
+
+/*
+ * Force and wait any uncommitted transactions. We can only force the running
+ * transaction if we don't have an active handle, otherwise, we will deadlock.
+ * Returns: <0 in case of error,
+ * 0 if nothing to commit,
+ * 1 if transaction was successfully committed.
+ */
+static int __jbd2_journal_force_commit(journal_t *journal)
+{
+ transaction_t *transaction = NULL;
+ tid_t tid;
+ int need_to_start = 0, ret = 0;
+
+ read_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction && !current->journal_info) {
+ transaction = journal->j_running_transaction;
+ if (!tid_geq(journal->j_commit_request, transaction->t_tid))
+ need_to_start = 1;
+ } else if (journal->j_committing_transaction)
+ transaction = journal->j_committing_transaction;
+
+ if (!transaction) {
+ /* Nothing to commit */
+ read_unlock(&journal->j_state_lock);
+ return 0;
+ }
+ tid = transaction->t_tid;
+ read_unlock(&journal->j_state_lock);
+ if (need_to_start)
+ jbd2_log_start_commit(journal, tid);
+ ret = jbd2_log_wait_commit(journal, tid);
+ if (!ret)
+ ret = 1;
+
+ return ret;
+}
+
+/**
+ * Force and wait upon a commit if the calling process is not within
+ * transaction. This is used for forcing out undo-protected data which contains
+ * bitmaps, when the fs is running out of space.
+ *
+ * @journal: journal to force
+ * Returns true if progress was made.
+ */
+int jbd2_journal_force_commit_nested(journal_t *journal)
+{
+ int ret;
+
+ ret = __jbd2_journal_force_commit(journal);
+ return ret > 0;
+}
+
+/**
+ * int journal_force_commit() - force any uncommitted transactions
+ * @journal: journal to force
+ *
+ * Caller want unconditional commit. We can only force the running transaction
+ * if we don't have an active handle, otherwise, we will deadlock.
+ */
+int jbd2_journal_force_commit(journal_t *journal)
+{
+ int ret;
+
+ J_ASSERT(!current->journal_info);
+ ret = __jbd2_journal_force_commit(journal);
+ if (ret > 0)
+ ret = 0;
+ return ret;
+}
+
+/*
+ * Start a commit of the current running transaction (if any). Returns true
+ * if a transaction is going to be committed (or is currently already
+ * committing), and fills its tid in at *ptid
+ */
+int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
+{
+ int ret = 0;
+
+ write_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction) {
+ tid_t tid = journal->j_running_transaction->t_tid;
+
+ __jbd2_log_start_commit(journal, tid);
+ /* There's a running transaction and we've just made sure
+ * it's commit has been scheduled. */
+ if (ptid)
+ *ptid = tid;
+ ret = 1;
+ } else if (journal->j_committing_transaction) {
+ /*
+ * If commit has been started, then we have to wait for
+ * completion of that transaction.
+ */
+ if (ptid)
+ *ptid = journal->j_committing_transaction->t_tid;
+ ret = 1;
+ }
+ write_unlock(&journal->j_state_lock);
+ return ret;
+}
+
+/*
+ * Return 1 if a given transaction has not yet sent barrier request
+ * connected with a transaction commit. If 0 is returned, transaction
+ * may or may not have sent the barrier. Used to avoid sending barrier
+ * twice in common cases.
+ */
+int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
+{
+ int ret = 0;
+ transaction_t *commit_trans;
+
+ if (!(journal->j_flags & JBD2_BARRIER))
+ return 0;
+ read_lock(&journal->j_state_lock);
+ /* Transaction already committed? */
+ if (tid_geq(journal->j_commit_sequence, tid))
+ goto out;
+ commit_trans = journal->j_committing_transaction;
+ if (!commit_trans || commit_trans->t_tid != tid) {
+ ret = 1;
+ goto out;
+ }
+ /*
+ * Transaction is being committed and we already proceeded to
+ * submitting a flush to fs partition?
+ */
+ if (journal->j_fs_dev != journal->j_dev) {
+ if (!commit_trans->t_need_data_flush ||
+ commit_trans->t_state >= T_COMMIT_DFLUSH)
+ goto out;
+ } else {
+ if (commit_trans->t_state >= T_COMMIT_JFLUSH)
+ goto out;
+ }
+ ret = 1;
+out:
+ read_unlock(&journal->j_state_lock);
+ return ret;
+}
+EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
+
+/*
+ * Wait for a specified commit to complete.
+ * The caller may not hold the journal lock.
+ */
+int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
+{
+ int err = 0;
+
+ read_lock(&journal->j_state_lock);
+#ifdef CONFIG_PROVE_LOCKING
+ /*
+ * Some callers make sure transaction is already committing and in that
+ * case we cannot block on open handles anymore. So don't warn in that
+ * case.
+ */
+ if (tid_gt(tid, journal->j_commit_sequence) &&
+ (!journal->j_committing_transaction ||
+ journal->j_committing_transaction->t_tid != tid)) {
+ read_unlock(&journal->j_state_lock);
+ jbd2_might_wait_for_commit(journal);
+ read_lock(&journal->j_state_lock);
+ }
+#endif
+#ifdef CONFIG_JBD2_DEBUG
+ if (!tid_geq(journal->j_commit_request, tid)) {
+ printk(KERN_ERR
+ "%s: error: j_commit_request=%d, tid=%d\n",
+ __func__, journal->j_commit_request, tid);
+ }
+#endif
+ while (tid_gt(tid, journal->j_commit_sequence)) {
+ jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
+ tid, journal->j_commit_sequence);
+ read_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_commit);
+ wait_event(journal->j_wait_done_commit,
+ !tid_gt(tid, journal->j_commit_sequence));
+ read_lock(&journal->j_state_lock);
+ }
+ read_unlock(&journal->j_state_lock);
+
+ if (unlikely(is_journal_aborted(journal)))
+ err = -EIO;
+ return err;
+}
+
+/* Return 1 when transaction with given tid has already committed. */
+int jbd2_transaction_committed(journal_t *journal, tid_t tid)
+{
+ int ret = 1;
+
+ read_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction &&
+ journal->j_running_transaction->t_tid == tid)
+ ret = 0;
+ if (journal->j_committing_transaction &&
+ journal->j_committing_transaction->t_tid == tid)
+ ret = 0;
+ read_unlock(&journal->j_state_lock);
+ return ret;
+}
+EXPORT_SYMBOL(jbd2_transaction_committed);
+
+/*
+ * When this function returns the transaction corresponding to tid
+ * will be completed. If the transaction has currently running, start
+ * committing that transaction before waiting for it to complete. If
+ * the transaction id is stale, it is by definition already completed,
+ * so just return SUCCESS.
+ */
+int jbd2_complete_transaction(journal_t *journal, tid_t tid)
+{
+ int need_to_wait = 1;
+
+ read_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction &&
+ journal->j_running_transaction->t_tid == tid) {
+ if (journal->j_commit_request != tid) {
+ /* transaction not yet started, so request it */
+ read_unlock(&journal->j_state_lock);
+ jbd2_log_start_commit(journal, tid);
+ goto wait_commit;
+ }
+ } else if (!(journal->j_committing_transaction &&
+ journal->j_committing_transaction->t_tid == tid))
+ need_to_wait = 0;
+ read_unlock(&journal->j_state_lock);
+ if (!need_to_wait)
+ return 0;
+wait_commit:
+ return jbd2_log_wait_commit(journal, tid);
+}
+EXPORT_SYMBOL(jbd2_complete_transaction);
+
+/*
+ * Log buffer allocation routines:
+ */
+
+int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
+{
+ unsigned long blocknr;
+
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(journal->j_free > 1);
+
+ blocknr = journal->j_head;
+ journal->j_head++;
+ journal->j_free--;
+ if (journal->j_head == journal->j_last)
+ journal->j_head = journal->j_first;
+ write_unlock(&journal->j_state_lock);
+ return jbd2_journal_bmap(journal, blocknr, retp);
+}
+
+/*
+ * Conversion of logical to physical block numbers for the journal
+ *
+ * On external journals the journal blocks are identity-mapped, so
+ * this is a no-op. If needed, we can use j_blk_offset - everything is
+ * ready.
+ */
+int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
+ unsigned long long *retp)
+{
+ int err = 0;
+ unsigned long long ret;
+
+ if (journal->j_inode) {
+ ret = bmap(journal->j_inode, blocknr);
+ if (ret)
+ *retp = ret;
+ else {
+ printk(KERN_ALERT "%s: journal block not found "
+ "at offset %lu on %s\n",
+ __func__, blocknr, journal->j_devname);
+ err = -EIO;
+ __journal_abort_soft(journal, err);
+ }
+ } else {
+ *retp = blocknr; /* +journal->j_blk_offset */
+ }
+ return err;
+}
+
+/*
+ * We play buffer_head aliasing tricks to write data/metadata blocks to
+ * the journal without copying their contents, but for journal
+ * descriptor blocks we do need to generate bona fide buffers.
+ *
+ * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
+ * the buffer's contents they really should run flush_dcache_page(bh->b_page).
+ * But we don't bother doing that, so there will be coherency problems with
+ * mmaps of blockdevs which hold live JBD-controlled filesystems.
+ */
+struct buffer_head *
+jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
+{
+ journal_t *journal = transaction->t_journal;
+ struct buffer_head *bh;
+ unsigned long long blocknr;
+ journal_header_t *header;
+ int err;
+
+ err = jbd2_journal_next_log_block(journal, &blocknr);
+
+ if (err)
+ return NULL;
+
+ bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+ if (!bh)
+ return NULL;
+ lock_buffer(bh);
+ memset(bh->b_data, 0, journal->j_blocksize);
+ header = (journal_header_t *)bh->b_data;
+ header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
+ header->h_blocktype = cpu_to_be32(type);
+ header->h_sequence = cpu_to_be32(transaction->t_tid);
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+ BUFFER_TRACE(bh, "return this buffer");
+ return bh;
+}
+
+void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
+{
+ struct jbd2_journal_block_tail *tail;
+ __u32 csum;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
+ sizeof(struct jbd2_journal_block_tail));
+ tail->t_checksum = 0;
+ csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
+ tail->t_checksum = cpu_to_be32(csum);
+}
+
+/*
+ * Return tid of the oldest transaction in the journal and block in the journal
+ * where the transaction starts.
+ *
+ * If the journal is now empty, return which will be the next transaction ID
+ * we will write and where will that transaction start.
+ *
+ * The return value is 0 if journal tail cannot be pushed any further, 1 if
+ * it can.
+ */
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+ unsigned long *block)
+{
+ transaction_t *transaction;
+ int ret;
+
+ read_lock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ transaction = journal->j_checkpoint_transactions;
+ if (transaction) {
+ *tid = transaction->t_tid;
+ *block = transaction->t_log_start;
+ } else if ((transaction = journal->j_committing_transaction) != NULL) {
+ *tid = transaction->t_tid;
+ *block = transaction->t_log_start;
+ } else if ((transaction = journal->j_running_transaction) != NULL) {
+ *tid = transaction->t_tid;
+ *block = journal->j_head;
+ } else {
+ *tid = journal->j_transaction_sequence;
+ *block = journal->j_head;
+ }
+ ret = tid_gt(*tid, journal->j_tail_sequence);
+ spin_unlock(&journal->j_list_lock);
+ read_unlock(&journal->j_state_lock);
+
+ return ret;
+}
+
+/*
+ * Update information in journal structure and in on disk journal superblock
+ * about log tail. This function does not check whether information passed in
+ * really pushes log tail further. It's responsibility of the caller to make
+ * sure provided log tail information is valid (e.g. by holding
+ * j_checkpoint_mutex all the time between computing log tail and calling this
+ * function as is the case with jbd2_cleanup_journal_tail()).
+ *
+ * Requires j_checkpoint_mutex
+ */
+int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+ unsigned long freed;
+ int ret;
+
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+
+ /*
+ * We cannot afford for write to remain in drive's caches since as
+ * soon as we update j_tail, next transaction can start reusing journal
+ * space and if we lose sb update during power failure we'd replay
+ * old transaction with possibly newly overwritten data.
+ */
+ ret = jbd2_journal_update_sb_log_tail(journal, tid, block,
+ REQ_SYNC | REQ_FUA);
+ if (ret)
+ goto out;
+
+ write_lock(&journal->j_state_lock);
+ freed = block - journal->j_tail;
+ if (block < journal->j_tail)
+ freed += journal->j_last - journal->j_first;
+
+ trace_jbd2_update_log_tail(journal, tid, block, freed);
+ jbd_debug(1,
+ "Cleaning journal tail from %d to %d (offset %lu), "
+ "freeing %lu\n",
+ journal->j_tail_sequence, tid, block, freed);
+
+ journal->j_free += freed;
+ journal->j_tail_sequence = tid;
+ journal->j_tail = block;
+ write_unlock(&journal->j_state_lock);
+
+out:
+ return ret;
+}
+
+/*
+ * This is a variation of __jbd2_update_log_tail which checks for validity of
+ * provided log tail and locks j_checkpoint_mutex. So it is safe against races
+ * with other threads updating log tail.
+ */
+void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ if (tid_gt(tid, journal->j_tail_sequence))
+ __jbd2_update_log_tail(journal, tid, block);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+}
+
+struct jbd2_stats_proc_session {
+ journal_t *journal;
+ struct transaction_stats_s *stats;
+ int start;
+ int max;
+};
+
+static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
+{
+ return *pos ? NULL : SEQ_START_TOKEN;
+}
+
+static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ return NULL;
+}
+
+static int jbd2_seq_info_show(struct seq_file *seq, void *v)
+{
+ struct jbd2_stats_proc_session *s = seq->private;
+
+ if (v != SEQ_START_TOKEN)
+ return 0;
+ seq_printf(seq, "%lu transactions (%lu requested), "
+ "each up to %u blocks\n",
+ s->stats->ts_tid, s->stats->ts_requested,
+ s->journal->j_max_transaction_buffers);
+ if (s->stats->ts_tid == 0)
+ return 0;
+ seq_printf(seq, "average: \n %ums waiting for transaction\n",
+ jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
+ seq_printf(seq, " %ums request delay\n",
+ (s->stats->ts_requested == 0) ? 0 :
+ jiffies_to_msecs(s->stats->run.rs_request_delay /
+ s->stats->ts_requested));
+ seq_printf(seq, " %ums running transaction\n",
+ jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
+ seq_printf(seq, " %ums transaction was being locked\n",
+ jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
+ seq_printf(seq, " %ums flushing data (in ordered mode)\n",
+ jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
+ seq_printf(seq, " %ums logging transaction\n",
+ jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
+ seq_printf(seq, " %lluus average transaction commit time\n",
+ div_u64(s->journal->j_average_commit_time, 1000));
+ seq_printf(seq, " %lu handles per transaction\n",
+ s->stats->run.rs_handle_count / s->stats->ts_tid);
+ seq_printf(seq, " %lu blocks per transaction\n",
+ s->stats->run.rs_blocks / s->stats->ts_tid);
+ seq_printf(seq, " %lu logged blocks per transaction\n",
+ s->stats->run.rs_blocks_logged / s->stats->ts_tid);
+ return 0;
+}
+
+static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
+{
+}
+
+static const struct seq_operations jbd2_seq_info_ops = {
+ .start = jbd2_seq_info_start,
+ .next = jbd2_seq_info_next,
+ .stop = jbd2_seq_info_stop,
+ .show = jbd2_seq_info_show,
+};
+
+static int jbd2_seq_info_open(struct inode *inode, struct file *file)
+{
+ journal_t *journal = PDE_DATA(inode);
+ struct jbd2_stats_proc_session *s;
+ int rc, size;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (s == NULL)
+ return -ENOMEM;
+ size = sizeof(struct transaction_stats_s);
+ s->stats = kmalloc(size, GFP_KERNEL);
+ if (s->stats == NULL) {
+ kfree(s);
+ return -ENOMEM;
+ }
+ spin_lock(&journal->j_history_lock);
+ memcpy(s->stats, &journal->j_stats, size);
+ s->journal = journal;
+ spin_unlock(&journal->j_history_lock);
+
+ rc = seq_open(file, &jbd2_seq_info_ops);
+ if (rc == 0) {
+ struct seq_file *m = file->private_data;
+ m->private = s;
+ } else {
+ kfree(s->stats);
+ kfree(s);
+ }
+ return rc;
+
+}
+
+static int jbd2_seq_info_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct jbd2_stats_proc_session *s = seq->private;
+ kfree(s->stats);
+ kfree(s);
+ return seq_release(inode, file);
+}
+
+static const struct file_operations jbd2_seq_info_fops = {
+ .owner = THIS_MODULE,
+ .open = jbd2_seq_info_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = jbd2_seq_info_release,
+};
+
+static struct proc_dir_entry *proc_jbd2_stats;
+
+static void jbd2_stats_proc_init(journal_t *journal)
+{
+ journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
+ if (journal->j_proc_entry) {
+ proc_create_data("info", S_IRUGO, journal->j_proc_entry,
+ &jbd2_seq_info_fops, journal);
+ }
+}
+
+static void jbd2_stats_proc_exit(journal_t *journal)
+{
+ remove_proc_entry("info", journal->j_proc_entry);
+ remove_proc_entry(journal->j_devname, proc_jbd2_stats);
+}
+
+/*
+ * Management for journal control blocks: functions to create and
+ * destroy journal_t structures, and to initialise and read existing
+ * journal blocks from disk. */
+
+/* First: create and setup a journal_t object in memory. We initialise
+ * very few fields yet: that has to wait until we have created the
+ * journal structures from from scratch, or loaded them from disk. */
+
+static journal_t *journal_init_common(struct block_device *bdev,
+ struct block_device *fs_dev,
+ unsigned long long start, int len, int blocksize)
+{
+ static struct lock_class_key jbd2_trans_commit_key;
+ journal_t *journal;
+ int err;
+ struct buffer_head *bh;
+ int n;
+
+ journal = kzalloc(sizeof(*journal), GFP_KERNEL);
+ if (!journal)
+ return NULL;
+
+ init_waitqueue_head(&journal->j_wait_transaction_locked);
+ init_waitqueue_head(&journal->j_wait_done_commit);
+ init_waitqueue_head(&journal->j_wait_commit);
+ init_waitqueue_head(&journal->j_wait_updates);
+ init_waitqueue_head(&journal->j_wait_reserved);
+ mutex_init(&journal->j_barrier);
+ mutex_init(&journal->j_checkpoint_mutex);
+ spin_lock_init(&journal->j_revoke_lock);
+ spin_lock_init(&journal->j_list_lock);
+ rwlock_init(&journal->j_state_lock);
+
+ journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
+ journal->j_min_batch_time = 0;
+ journal->j_max_batch_time = 15000; /* 15ms */
+ atomic_set(&journal->j_reserved_credits, 0);
+
+ /* The journal is marked for error until we succeed with recovery! */
+ journal->j_flags = JBD2_ABORT;
+
+ /* Set up a default-sized revoke table for the new mount. */
+ err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
+ if (err)
+ goto err_cleanup;
+
+ spin_lock_init(&journal->j_history_lock);
+
+ lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
+ &jbd2_trans_commit_key, 0);
+
+ /* journal descriptor can store up to n blocks -bzzz */
+ journal->j_blocksize = blocksize;
+ journal->j_dev = bdev;
+ journal->j_fs_dev = fs_dev;
+ journal->j_blk_offset = start;
+ journal->j_maxlen = len;
+ n = journal->j_blocksize / sizeof(journal_block_tag_t);
+ journal->j_wbufsize = n;
+ journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
+ GFP_KERNEL);
+ if (!journal->j_wbuf)
+ goto err_cleanup;
+
+ bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
+ if (!bh) {
+ pr_err("%s: Cannot get buffer for journal superblock\n",
+ __func__);
+ goto err_cleanup;
+ }
+ journal->j_sb_buffer = bh;
+ journal->j_superblock = (journal_superblock_t *)bh->b_data;
+
+ return journal;
+
+err_cleanup:
+ kfree(journal->j_wbuf);
+ jbd2_journal_destroy_revoke(journal);
+ kfree(journal);
+ return NULL;
+}
+
+/* jbd2_journal_init_dev and jbd2_journal_init_inode:
+ *
+ * Create a journal structure assigned some fixed set of disk blocks to
+ * the journal. We don't actually touch those disk blocks yet, but we
+ * need to set up all of the mapping information to tell the journaling
+ * system where the journal blocks are.
+ *
+ */
+
+/**
+ * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
+ * @bdev: Block device on which to create the journal
+ * @fs_dev: Device which hold journalled filesystem for this journal.
+ * @start: Block nr Start of journal.
+ * @len: Length of the journal in blocks.
+ * @blocksize: blocksize of journalling device
+ *
+ * Returns: a newly created journal_t *
+ *
+ * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
+ * range of blocks on an arbitrary block device.
+ *
+ */
+journal_t *jbd2_journal_init_dev(struct block_device *bdev,
+ struct block_device *fs_dev,
+ unsigned long long start, int len, int blocksize)
+{
+ journal_t *journal;
+
+ journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
+ if (!journal)
+ return NULL;
+
+ bdevname(journal->j_dev, journal->j_devname);
+ strreplace(journal->j_devname, '/', '!');
+ jbd2_stats_proc_init(journal);
+
+ return journal;
+}
+
+/**
+ * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
+ * @inode: An inode to create the journal in
+ *
+ * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
+ * the journal. The inode must exist already, must support bmap() and
+ * must have all data blocks preallocated.
+ */
+journal_t *jbd2_journal_init_inode(struct inode *inode)
+{
+ journal_t *journal;
+ char *p;
+ unsigned long long blocknr;
+
+ blocknr = bmap(inode, 0);
+ if (!blocknr) {
+ pr_err("%s: Cannot locate journal superblock\n",
+ __func__);
+ return NULL;
+ }
+
+ jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
+ inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
+ inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
+
+ journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
+ blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
+ inode->i_sb->s_blocksize);
+ if (!journal)
+ return NULL;
+
+ journal->j_inode = inode;
+ bdevname(journal->j_dev, journal->j_devname);
+ p = strreplace(journal->j_devname, '/', '!');
+ sprintf(p, "-%lu", journal->j_inode->i_ino);
+ jbd2_stats_proc_init(journal);
+
+ return journal;
+}
+
+/*
+ * If the journal init or create aborts, we need to mark the journal
+ * superblock as being NULL to prevent the journal destroy from writing
+ * back a bogus superblock.
+ */
+static void journal_fail_superblock (journal_t *journal)
+{
+ struct buffer_head *bh = journal->j_sb_buffer;
+ brelse(bh);
+ journal->j_sb_buffer = NULL;
+}
+
+/*
+ * Given a journal_t structure, initialise the various fields for
+ * startup of a new journaling session. We use this both when creating
+ * a journal, and after recovering an old journal to reset it for
+ * subsequent use.
+ */
+
+static int journal_reset(journal_t *journal)
+{
+ journal_superblock_t *sb = journal->j_superblock;
+ unsigned long long first, last;
+
+ first = be32_to_cpu(sb->s_first);
+ last = be32_to_cpu(sb->s_maxlen);
+ if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
+ printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
+ first, last);
+ journal_fail_superblock(journal);
+ return -EINVAL;
+ }
+
+ journal->j_first = first;
+ journal->j_last = last;
+
+ journal->j_head = first;
+ journal->j_tail = first;
+ journal->j_free = last - first;
+
+ journal->j_tail_sequence = journal->j_transaction_sequence;
+ journal->j_commit_sequence = journal->j_transaction_sequence - 1;
+ journal->j_commit_request = journal->j_commit_sequence;
+
+ journal->j_max_transaction_buffers = journal->j_maxlen / 4;
+
+ /*
+ * As a special case, if the on-disk copy is already marked as needing
+ * no recovery (s_start == 0), then we can safely defer the superblock
+ * update until the next commit by setting JBD2_FLUSHED. This avoids
+ * attempting a write to a potential-readonly device.
+ */
+ if (sb->s_start == 0) {
+ jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
+ "(start %ld, seq %d, errno %d)\n",
+ journal->j_tail, journal->j_tail_sequence,
+ journal->j_errno);
+ journal->j_flags |= JBD2_FLUSHED;
+ } else {
+ /* Lock here to make assertions happy... */
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ /*
+ * Update log tail information. We use REQ_FUA since new
+ * transaction will start reusing journal space and so we
+ * must make sure information about current log tail is on
+ * disk before that.
+ */
+ jbd2_journal_update_sb_log_tail(journal,
+ journal->j_tail_sequence,
+ journal->j_tail,
+ REQ_SYNC | REQ_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
+ return jbd2_journal_start_thread(journal);
+}
+
+static int jbd2_write_superblock(journal_t *journal, int write_flags)
+{
+ struct buffer_head *bh = journal->j_sb_buffer;
+ journal_superblock_t *sb = journal->j_superblock;
+ int ret;
+
+ trace_jbd2_write_superblock(journal, write_flags);
+ if (!(journal->j_flags & JBD2_BARRIER))
+ write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
+ lock_buffer(bh);
+ if (buffer_write_io_error(bh)) {
+ /*
+ * Oh, dear. A previous attempt to write the journal
+ * superblock failed. This could happen because the
+ * USB device was yanked out. Or it could happen to
+ * be a transient write error and maybe the block will
+ * be remapped. Nothing we can do but to retry the
+ * write and hope for the best.
+ */
+ printk(KERN_ERR "JBD2: previous I/O error detected "
+ "for journal superblock update for %s.\n",
+ journal->j_devname);
+ clear_buffer_write_io_error(bh);
+ set_buffer_uptodate(bh);
+ }
+ jbd2_superblock_csum_set(journal, sb);
+ get_bh(bh);
+ bh->b_end_io = end_buffer_write_sync;
+ ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
+ wait_on_buffer(bh);
+ if (buffer_write_io_error(bh)) {
+ clear_buffer_write_io_error(bh);
+ set_buffer_uptodate(bh);
+ ret = -EIO;
+ }
+ if (ret) {
+ printk(KERN_ERR "JBD2: Error %d detected when updating "
+ "journal superblock for %s.\n", ret,
+ journal->j_devname);
+ jbd2_journal_abort(journal, ret);
+ }
+
+ return ret;
+}
+
+/**
+ * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
+ * @journal: The journal to update.
+ * @tail_tid: TID of the new transaction at the tail of the log
+ * @tail_block: The first block of the transaction at the tail of the log
+ * @write_op: With which operation should we write the journal sb
+ *
+ * Update a journal's superblock information about log tail and write it to
+ * disk, waiting for the IO to complete.
+ */
+int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
+ unsigned long tail_block, int write_op)
+{
+ journal_superblock_t *sb = journal->j_superblock;
+ int ret;
+
+ if (is_journal_aborted(journal))
+ return -EIO;
+
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+ jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
+ tail_block, tail_tid);
+
+ sb->s_sequence = cpu_to_be32(tail_tid);
+ sb->s_start = cpu_to_be32(tail_block);
+
+ ret = jbd2_write_superblock(journal, write_op);
+ if (ret)
+ goto out;
+
+ /* Log is no longer empty */
+ write_lock(&journal->j_state_lock);
+ WARN_ON(!sb->s_sequence);
+ journal->j_flags &= ~JBD2_FLUSHED;
+ write_unlock(&journal->j_state_lock);
+
+out:
+ return ret;
+}
+
+/**
+ * jbd2_mark_journal_empty() - Mark on disk journal as empty.
+ * @journal: The journal to update.
+ * @write_op: With which operation should we write the journal sb
+ *
+ * Update a journal's dynamic superblock fields to show that journal is empty.
+ * Write updated superblock to disk waiting for IO to complete.
+ */
+static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
+{
+ journal_superblock_t *sb = journal->j_superblock;
+
+ BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+ read_lock(&journal->j_state_lock);
+ /* Is it already empty? */
+ if (sb->s_start == 0) {
+ read_unlock(&journal->j_state_lock);
+ return;
+ }
+ jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
+ journal->j_tail_sequence);
+
+ sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
+ sb->s_start = cpu_to_be32(0);
+ read_unlock(&journal->j_state_lock);
+
+ jbd2_write_superblock(journal, write_op);
+
+ /* Log is no longer empty */
+ write_lock(&journal->j_state_lock);
+ journal->j_flags |= JBD2_FLUSHED;
+ write_unlock(&journal->j_state_lock);
+}
+
+
+/**
+ * jbd2_journal_update_sb_errno() - Update error in the journal.
+ * @journal: The journal to update.
+ *
+ * Update a journal's errno. Write updated superblock to disk waiting for IO
+ * to complete.
+ */
+void jbd2_journal_update_sb_errno(journal_t *journal)
+{
+ journal_superblock_t *sb = journal->j_superblock;
+ int errcode;
+
+ read_lock(&journal->j_state_lock);
+ errcode = journal->j_errno;
+ read_unlock(&journal->j_state_lock);
+ if (errcode == -ESHUTDOWN)
+ errcode = 0;
+ jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
+ sb->s_errno = cpu_to_be32(errcode);
+
+ jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA);
+}
+EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
+
+/*
+ * Read the superblock for a given journal, performing initial
+ * validation of the format.
+ */
+static int journal_get_superblock(journal_t *journal)
+{
+ struct buffer_head *bh;
+ journal_superblock_t *sb;
+ int err = -EIO;
+
+ bh = journal->j_sb_buffer;
+
+ J_ASSERT(bh != NULL);
+ if (!buffer_uptodate(bh)) {
+ ll_rw_block(REQ_OP_READ, 0, 1, &bh);
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh)) {
+ printk(KERN_ERR
+ "JBD2: IO error reading journal superblock\n");
+ goto out;
+ }
+ }
+
+ if (buffer_verified(bh))
+ return 0;
+
+ sb = journal->j_superblock;
+
+ err = -EINVAL;
+
+ if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
+ sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
+ printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
+ goto out;
+ }
+
+ switch(be32_to_cpu(sb->s_header.h_blocktype)) {
+ case JBD2_SUPERBLOCK_V1:
+ journal->j_format_version = 1;
+ break;
+ case JBD2_SUPERBLOCK_V2:
+ journal->j_format_version = 2;
+ break;
+ default:
+ printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
+ goto out;
+ }
+
+ if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
+ journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
+ else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
+ printk(KERN_WARNING "JBD2: journal file too short\n");
+ goto out;
+ }
+
+ if (be32_to_cpu(sb->s_first) == 0 ||
+ be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
+ printk(KERN_WARNING
+ "JBD2: Invalid start block of journal: %u\n",
+ be32_to_cpu(sb->s_first));
+ goto out;
+ }
+
+ if (jbd2_has_feature_csum2(journal) &&
+ jbd2_has_feature_csum3(journal)) {
+ /* Can't have checksum v2 and v3 at the same time! */
+ printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
+ "at the same time!\n");
+ goto out;
+ }
+
+ if (jbd2_journal_has_csum_v2or3_feature(journal) &&
+ jbd2_has_feature_checksum(journal)) {
+ /* Can't have checksum v1 and v2 on at the same time! */
+ printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
+ "at the same time!\n");
+ goto out;
+ }
+
+ if (!jbd2_verify_csum_type(journal, sb)) {
+ printk(KERN_ERR "JBD2: Unknown checksum type\n");
+ goto out;
+ }
+
+ /* Load the checksum driver */
+ if (jbd2_journal_has_csum_v2or3_feature(journal)) {
+ journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
+ if (IS_ERR(journal->j_chksum_driver)) {
+ printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
+ err = PTR_ERR(journal->j_chksum_driver);
+ journal->j_chksum_driver = NULL;
+ goto out;
+ }
+ }
+
+ /* Check superblock checksum */
+ if (!jbd2_superblock_csum_verify(journal, sb)) {
+ printk(KERN_ERR "JBD2: journal checksum error\n");
+ err = -EFSBADCRC;
+ goto out;
+ }
+
+ /* Precompute checksum seed for all metadata */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
+ sizeof(sb->s_uuid));
+
+ set_buffer_verified(bh);
+
+ return 0;
+
+out:
+ journal_fail_superblock(journal);
+ return err;
+}
+
+/*
+ * Load the on-disk journal superblock and read the key fields into the
+ * journal_t.
+ */
+
+static int load_superblock(journal_t *journal)
+{
+ int err;
+ journal_superblock_t *sb;
+
+ err = journal_get_superblock(journal);
+ if (err)
+ return err;
+
+ sb = journal->j_superblock;
+
+ journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
+ journal->j_tail = be32_to_cpu(sb->s_start);
+ journal->j_first = be32_to_cpu(sb->s_first);
+ journal->j_last = be32_to_cpu(sb->s_maxlen);
+ journal->j_errno = be32_to_cpu(sb->s_errno);
+
+ return 0;
+}
+
+
+/**
+ * int jbd2_journal_load() - Read journal from disk.
+ * @journal: Journal to act on.
+ *
+ * Given a journal_t structure which tells us which disk blocks contain
+ * a journal, read the journal from disk to initialise the in-memory
+ * structures.
+ */
+int jbd2_journal_load(journal_t *journal)
+{
+ int err;
+ journal_superblock_t *sb;
+
+ err = load_superblock(journal);
+ if (err)
+ return err;
+
+ sb = journal->j_superblock;
+ /* If this is a V2 superblock, then we have to check the
+ * features flags on it. */
+
+ if (journal->j_format_version >= 2) {
+ if ((sb->s_feature_ro_compat &
+ ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
+ (sb->s_feature_incompat &
+ ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
+ printk(KERN_WARNING
+ "JBD2: Unrecognised features on journal\n");
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Create a slab for this blocksize
+ */
+ err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
+ if (err)
+ return err;
+
+ /* Let the recovery code check whether it needs to recover any
+ * data from the journal. */
+ if (jbd2_journal_recover(journal))
+ goto recovery_error;
+
+ if (journal->j_failed_commit) {
+ printk(KERN_ERR "JBD2: journal transaction %u on %s "
+ "is corrupt.\n", journal->j_failed_commit,
+ journal->j_devname);
+ return -EFSCORRUPTED;
+ }
+
+ /* OK, we've finished with the dynamic journal bits:
+ * reinitialise the dynamic contents of the superblock in memory
+ * and reset them on disk. */
+ if (journal_reset(journal))
+ goto recovery_error;
+
+ journal->j_flags &= ~JBD2_ABORT;
+ journal->j_flags |= JBD2_LOADED;
+ return 0;
+
+recovery_error:
+ printk(KERN_WARNING "JBD2: recovery failed\n");
+ return -EIO;
+}
+
+/**
+ * void jbd2_journal_destroy() - Release a journal_t structure.
+ * @journal: Journal to act on.
+ *
+ * Release a journal_t structure once it is no longer in use by the
+ * journaled object.
+ * Return <0 if we couldn't clean up the journal.
+ */
+int jbd2_journal_destroy(journal_t *journal)
+{
+ int err = 0;
+
+ /* Wait for the commit thread to wake up and die. */
+ journal_kill_thread(journal);
+
+ /* Force a final log commit */
+ if (journal->j_running_transaction)
+ jbd2_journal_commit_transaction(journal);
+
+ /* Force any old transactions to disk */
+
+ /* Totally anal locking here... */
+ spin_lock(&journal->j_list_lock);
+ while (journal->j_checkpoint_transactions != NULL) {
+ spin_unlock(&journal->j_list_lock);
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ err = jbd2_log_do_checkpoint(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ /*
+ * If checkpointing failed, just free the buffers to avoid
+ * looping forever
+ */
+ if (err) {
+ jbd2_journal_destroy_checkpoint(journal);
+ spin_lock(&journal->j_list_lock);
+ break;
+ }
+ spin_lock(&journal->j_list_lock);
+ }
+
+ J_ASSERT(journal->j_running_transaction == NULL);
+ J_ASSERT(journal->j_committing_transaction == NULL);
+ J_ASSERT(journal->j_checkpoint_transactions == NULL);
+ spin_unlock(&journal->j_list_lock);
+
+ if (journal->j_sb_buffer) {
+ if (!is_journal_aborted(journal)) {
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+
+ write_lock(&journal->j_state_lock);
+ journal->j_tail_sequence =
+ ++journal->j_transaction_sequence;
+ write_unlock(&journal->j_state_lock);
+
+ jbd2_mark_journal_empty(journal,
+ REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ } else
+ err = -EIO;
+ brelse(journal->j_sb_buffer);
+ }
+
+ if (journal->j_proc_entry)
+ jbd2_stats_proc_exit(journal);
+ iput(journal->j_inode);
+ if (journal->j_revoke)
+ jbd2_journal_destroy_revoke(journal);
+ if (journal->j_chksum_driver)
+ crypto_free_shash(journal->j_chksum_driver);
+ kfree(journal->j_wbuf);
+ kfree(journal);
+
+ return err;
+}
+
+
+/**
+ *int jbd2_journal_check_used_features () - Check if features specified are used.
+ * @journal: Journal to check.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
+ * Check whether the journal uses all of a given set of
+ * features. Return true (non-zero) if it does.
+ **/
+
+int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
+ unsigned long ro, unsigned long incompat)
+{
+ journal_superblock_t *sb;
+
+ if (!compat && !ro && !incompat)
+ return 1;
+ /* Load journal superblock if it is not loaded yet. */
+ if (journal->j_format_version == 0 &&
+ journal_get_superblock(journal) != 0)
+ return 0;
+ if (journal->j_format_version == 1)
+ return 0;
+
+ sb = journal->j_superblock;
+
+ if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
+ ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
+ ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
+ return 1;
+
+ return 0;
+}
+
+/**
+ * int jbd2_journal_check_available_features() - Check feature set in journalling layer
+ * @journal: Journal to check.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
+ * Check whether the journaling code supports the use of
+ * all of a given set of features on this journal. Return true
+ * (non-zero) if it can. */
+
+int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
+ unsigned long ro, unsigned long incompat)
+{
+ if (!compat && !ro && !incompat)
+ return 1;
+
+ /* We can support any known requested features iff the
+ * superblock is in version 2. Otherwise we fail to support any
+ * extended sb features. */
+
+ if (journal->j_format_version != 2)
+ return 0;
+
+ if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
+ (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
+ (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
+ return 1;
+
+ return 0;
+}
+
+/**
+ * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
+ * @journal: Journal to act on.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
+ * Mark a given journal feature as present on the
+ * superblock. Returns true if the requested features could be set.
+ *
+ */
+
+int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
+ unsigned long ro, unsigned long incompat)
+{
+#define INCOMPAT_FEATURE_ON(f) \
+ ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
+#define COMPAT_FEATURE_ON(f) \
+ ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
+ journal_superblock_t *sb;
+
+ if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
+ return 1;
+
+ if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
+ return 0;
+
+ /* If enabling v2 checksums, turn on v3 instead */
+ if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
+ incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
+ incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
+ }
+
+ /* Asking for checksumming v3 and v1? Only give them v3. */
+ if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
+ compat & JBD2_FEATURE_COMPAT_CHECKSUM)
+ compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
+
+ jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
+ compat, ro, incompat);
+
+ sb = journal->j_superblock;
+
+ /* If enabling v3 checksums, update superblock */
+ if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
+ sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
+ sb->s_feature_compat &=
+ ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
+
+ /* Load the checksum driver */
+ if (journal->j_chksum_driver == NULL) {
+ journal->j_chksum_driver = crypto_alloc_shash("crc32c",
+ 0, 0);
+ if (IS_ERR(journal->j_chksum_driver)) {
+ printk(KERN_ERR "JBD2: Cannot load crc32c "
+ "driver.\n");
+ journal->j_chksum_driver = NULL;
+ return 0;
+ }
+
+ /* Precompute checksum seed for all metadata */
+ journal->j_csum_seed = jbd2_chksum(journal, ~0,
+ sb->s_uuid,
+ sizeof(sb->s_uuid));
+ }
+ }
+
+ /* If enabling v1 checksums, downgrade superblock */
+ if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
+ sb->s_feature_incompat &=
+ ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
+ JBD2_FEATURE_INCOMPAT_CSUM_V3);
+
+ sb->s_feature_compat |= cpu_to_be32(compat);
+ sb->s_feature_ro_compat |= cpu_to_be32(ro);
+ sb->s_feature_incompat |= cpu_to_be32(incompat);
+
+ return 1;
+#undef COMPAT_FEATURE_ON
+#undef INCOMPAT_FEATURE_ON
+}
+
+/*
+ * jbd2_journal_clear_features () - Clear a given journal feature in the
+ * superblock
+ * @journal: Journal to act on.
+ * @compat: bitmask of compatible features
+ * @ro: bitmask of features that force read-only mount
+ * @incompat: bitmask of incompatible features
+ *
+ * Clear a given journal feature as present on the
+ * superblock.
+ */
+void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
+ unsigned long ro, unsigned long incompat)
+{
+ journal_superblock_t *sb;
+
+ jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
+ compat, ro, incompat);
+
+ sb = journal->j_superblock;
+
+ sb->s_feature_compat &= ~cpu_to_be32(compat);
+ sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
+ sb->s_feature_incompat &= ~cpu_to_be32(incompat);
+}
+EXPORT_SYMBOL(jbd2_journal_clear_features);
+
+/**
+ * int jbd2_journal_flush () - Flush journal
+ * @journal: Journal to act on.
+ *
+ * Flush all data for a given journal to disk and empty the journal.
+ * Filesystems can use this when remounting readonly to ensure that
+ * recovery does not need to happen on remount.
+ */
+
+int jbd2_journal_flush(journal_t *journal)
+{
+ int err = 0;
+ transaction_t *transaction = NULL;
+
+ write_lock(&journal->j_state_lock);
+
+ /* Force everything buffered to the log... */
+ if (journal->j_running_transaction) {
+ transaction = journal->j_running_transaction;
+ __jbd2_log_start_commit(journal, transaction->t_tid);
+ } else if (journal->j_committing_transaction)
+ transaction = journal->j_committing_transaction;
+
+ /* Wait for the log commit to complete... */
+ if (transaction) {
+ tid_t tid = transaction->t_tid;
+
+ write_unlock(&journal->j_state_lock);
+ jbd2_log_wait_commit(journal, tid);
+ } else {
+ write_unlock(&journal->j_state_lock);
+ }
+
+ /* ...and flush everything in the log out to disk. */
+ spin_lock(&journal->j_list_lock);
+ while (!err && journal->j_checkpoint_transactions != NULL) {
+ spin_unlock(&journal->j_list_lock);
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ err = jbd2_log_do_checkpoint(journal);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ spin_lock(&journal->j_list_lock);
+ }
+ spin_unlock(&journal->j_list_lock);
+
+ if (is_journal_aborted(journal))
+ return -EIO;
+
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ if (!err) {
+ err = jbd2_cleanup_journal_tail(journal);
+ if (err < 0) {
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ goto out;
+ }
+ err = 0;
+ }
+
+ /* Finally, mark the journal as really needing no recovery.
+ * This sets s_start==0 in the underlying superblock, which is
+ * the magic code for a fully-recovered superblock. Any future
+ * commits of data to the journal will restore the current
+ * s_start value. */
+ jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(!journal->j_running_transaction);
+ J_ASSERT(!journal->j_committing_transaction);
+ J_ASSERT(!journal->j_checkpoint_transactions);
+ J_ASSERT(journal->j_head == journal->j_tail);
+ J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
+ write_unlock(&journal->j_state_lock);
+out:
+ return err;
+}
+
+/**
+ * int jbd2_journal_wipe() - Wipe journal contents
+ * @journal: Journal to act on.
+ * @write: flag (see below)
+ *
+ * Wipe out all of the contents of a journal, safely. This will produce
+ * a warning if the journal contains any valid recovery information.
+ * Must be called between journal_init_*() and jbd2_journal_load().
+ *
+ * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
+ * we merely suppress recovery.
+ */
+
+int jbd2_journal_wipe(journal_t *journal, int write)
+{
+ int err = 0;
+
+ J_ASSERT (!(journal->j_flags & JBD2_LOADED));
+
+ err = load_superblock(journal);
+ if (err)
+ return err;
+
+ if (!journal->j_tail)
+ goto no_recovery;
+
+ printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
+ write ? "Clearing" : "Ignoring");
+
+ err = jbd2_journal_skip_recovery(journal);
+ if (write) {
+ /* Lock to make assertions happy... */
+ mutex_lock(&journal->j_checkpoint_mutex);
+ jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
+
+ no_recovery:
+ return err;
+}
+
+/*
+ * Journal abort has very specific semantics, which we describe
+ * for journal abort.
+ *
+ * Two internal functions, which provide abort to the jbd layer
+ * itself are here.
+ */
+
+/*
+ * Quick version for internal journal use (doesn't lock the journal).
+ * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
+ * and don't attempt to make any other journal updates.
+ */
+void __jbd2_journal_abort_hard(journal_t *journal)
+{
+ transaction_t *transaction;
+
+ if (journal->j_flags & JBD2_ABORT)
+ return;
+
+ printk(KERN_ERR "Aborting journal on device %s.\n",
+ journal->j_devname);
+
+ write_lock(&journal->j_state_lock);
+ journal->j_flags |= JBD2_ABORT;
+ transaction = journal->j_running_transaction;
+ if (transaction)
+ __jbd2_log_start_commit(journal, transaction->t_tid);
+ write_unlock(&journal->j_state_lock);
+}
+
+/* Soft abort: record the abort error status in the journal superblock,
+ * but don't do any other IO. */
+static void __journal_abort_soft (journal_t *journal, int errno)
+{
+ int old_errno;
+
+ write_lock(&journal->j_state_lock);
+ old_errno = journal->j_errno;
+ if (!journal->j_errno || errno == -ESHUTDOWN)
+ journal->j_errno = errno;
+
+ if (journal->j_flags & JBD2_ABORT) {
+ write_unlock(&journal->j_state_lock);
+ if (!old_errno && old_errno != -ESHUTDOWN &&
+ errno == -ESHUTDOWN)
+ jbd2_journal_update_sb_errno(journal);
+ return;
+ }
+ write_unlock(&journal->j_state_lock);
+
+ __jbd2_journal_abort_hard(journal);
+
+ if (errno) {
+ jbd2_journal_update_sb_errno(journal);
+ write_lock(&journal->j_state_lock);
+ journal->j_flags |= JBD2_REC_ERR;
+ write_unlock(&journal->j_state_lock);
+ }
+}
+
+/**
+ * void jbd2_journal_abort () - Shutdown the journal immediately.
+ * @journal: the journal to shutdown.
+ * @errno: an error number to record in the journal indicating
+ * the reason for the shutdown.
+ *
+ * Perform a complete, immediate shutdown of the ENTIRE
+ * journal (not of a single transaction). This operation cannot be
+ * undone without closing and reopening the journal.
+ *
+ * The jbd2_journal_abort function is intended to support higher level error
+ * recovery mechanisms such as the ext2/ext3 remount-readonly error
+ * mode.
+ *
+ * Journal abort has very specific semantics. Any existing dirty,
+ * unjournaled buffers in the main filesystem will still be written to
+ * disk by bdflush, but the journaling mechanism will be suspended
+ * immediately and no further transaction commits will be honoured.
+ *
+ * Any dirty, journaled buffers will be written back to disk without
+ * hitting the journal. Atomicity cannot be guaranteed on an aborted
+ * filesystem, but we _do_ attempt to leave as much data as possible
+ * behind for fsck to use for cleanup.
+ *
+ * Any attempt to get a new transaction handle on a journal which is in
+ * ABORT state will just result in an -EROFS error return. A
+ * jbd2_journal_stop on an existing handle will return -EIO if we have
+ * entered abort state during the update.
+ *
+ * Recursive transactions are not disturbed by journal abort until the
+ * final jbd2_journal_stop, which will receive the -EIO error.
+ *
+ * Finally, the jbd2_journal_abort call allows the caller to supply an errno
+ * which will be recorded (if possible) in the journal superblock. This
+ * allows a client to record failure conditions in the middle of a
+ * transaction without having to complete the transaction to record the
+ * failure to disk. ext3_error, for example, now uses this
+ * functionality.
+ *
+ * Errors which originate from within the journaling layer will NOT
+ * supply an errno; a null errno implies that absolutely no further
+ * writes are done to the journal (unless there are any already in
+ * progress).
+ *
+ */
+
+void jbd2_journal_abort(journal_t *journal, int errno)
+{
+ __journal_abort_soft(journal, errno);
+}
+
+/**
+ * int jbd2_journal_errno () - returns the journal's error state.
+ * @journal: journal to examine.
+ *
+ * This is the errno number set with jbd2_journal_abort(), the last
+ * time the journal was mounted - if the journal was stopped
+ * without calling abort this will be 0.
+ *
+ * If the journal has been aborted on this mount time -EROFS will
+ * be returned.
+ */
+int jbd2_journal_errno(journal_t *journal)
+{
+ int err;
+
+ read_lock(&journal->j_state_lock);
+ if (journal->j_flags & JBD2_ABORT)
+ err = -EROFS;
+ else
+ err = journal->j_errno;
+ read_unlock(&journal->j_state_lock);
+ return err;
+}
+
+/**
+ * int jbd2_journal_clear_err () - clears the journal's error state
+ * @journal: journal to act on.
+ *
+ * An error must be cleared or acked to take a FS out of readonly
+ * mode.
+ */
+int jbd2_journal_clear_err(journal_t *journal)
+{
+ int err = 0;
+
+ write_lock(&journal->j_state_lock);
+ if (journal->j_flags & JBD2_ABORT)
+ err = -EROFS;
+ else
+ journal->j_errno = 0;
+ write_unlock(&journal->j_state_lock);
+ return err;
+}
+
+/**
+ * void jbd2_journal_ack_err() - Ack journal err.
+ * @journal: journal to act on.
+ *
+ * An error must be cleared or acked to take a FS out of readonly
+ * mode.
+ */
+void jbd2_journal_ack_err(journal_t *journal)
+{
+ write_lock(&journal->j_state_lock);
+ if (journal->j_errno)
+ journal->j_flags |= JBD2_ACK_ERR;
+ write_unlock(&journal->j_state_lock);
+}
+
+int jbd2_journal_blocks_per_page(struct inode *inode)
+{
+ return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
+}
+
+/*
+ * helper functions to deal with 32 or 64bit block numbers.
+ */
+size_t journal_tag_bytes(journal_t *journal)
+{
+ size_t sz;
+
+ if (jbd2_has_feature_csum3(journal))
+ return sizeof(journal_block_tag3_t);
+
+ sz = sizeof(journal_block_tag_t);
+
+ if (jbd2_has_feature_csum2(journal))
+ sz += sizeof(__u16);
+
+ if (jbd2_has_feature_64bit(journal))
+ return sz;
+ else
+ return sz - sizeof(__u32);
+}
+
+/*
+ * JBD memory management
+ *
+ * These functions are used to allocate block-sized chunks of memory
+ * used for making copies of buffer_head data. Very often it will be
+ * page-sized chunks of data, but sometimes it will be in
+ * sub-page-size chunks. (For example, 16k pages on Power systems
+ * with a 4k block file system.) For blocks smaller than a page, we
+ * use a SLAB allocator. There are slab caches for each block size,
+ * which are allocated at mount time, if necessary, and we only free
+ * (all of) the slab caches when/if the jbd2 module is unloaded. For
+ * this reason we don't need to a mutex to protect access to
+ * jbd2_slab[] allocating or releasing memory; only in
+ * jbd2_journal_create_slab().
+ */
+#define JBD2_MAX_SLABS 8
+static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
+
+static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
+ "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
+ "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
+};
+
+
+static void jbd2_journal_destroy_slabs(void)
+{
+ int i;
+
+ for (i = 0; i < JBD2_MAX_SLABS; i++) {
+ kmem_cache_destroy(jbd2_slab[i]);
+ jbd2_slab[i] = NULL;
+ }
+}
+
+static int jbd2_journal_create_slab(size_t size)
+{
+ static DEFINE_MUTEX(jbd2_slab_create_mutex);
+ int i = order_base_2(size) - 10;
+ size_t slab_size;
+
+ if (size == PAGE_SIZE)
+ return 0;
+
+ if (i >= JBD2_MAX_SLABS)
+ return -EINVAL;
+
+ if (unlikely(i < 0))
+ i = 0;
+ mutex_lock(&jbd2_slab_create_mutex);
+ if (jbd2_slab[i]) {
+ mutex_unlock(&jbd2_slab_create_mutex);
+ return 0; /* Already created */
+ }
+
+ slab_size = 1 << (i+10);
+ jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
+ slab_size, 0, NULL);
+ mutex_unlock(&jbd2_slab_create_mutex);
+ if (!jbd2_slab[i]) {
+ printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static struct kmem_cache *get_slab(size_t size)
+{
+ int i = order_base_2(size) - 10;
+
+ BUG_ON(i >= JBD2_MAX_SLABS);
+ if (unlikely(i < 0))
+ i = 0;
+ BUG_ON(jbd2_slab[i] == NULL);
+ return jbd2_slab[i];
+}
+
+void *jbd2_alloc(size_t size, gfp_t flags)
+{
+ void *ptr;
+
+ BUG_ON(size & (size-1)); /* Must be a power of 2 */
+
+ if (size < PAGE_SIZE)
+ ptr = kmem_cache_alloc(get_slab(size), flags);
+ else
+ ptr = (void *)__get_free_pages(flags, get_order(size));
+
+ /* Check alignment; SLUB has gotten this wrong in the past,
+ * and this can lead to user data corruption! */
+ BUG_ON(((unsigned long) ptr) & (size-1));
+
+ return ptr;
+}
+
+void jbd2_free(void *ptr, size_t size)
+{
+ if (size < PAGE_SIZE)
+ kmem_cache_free(get_slab(size), ptr);
+ else
+ free_pages((unsigned long)ptr, get_order(size));
+};
+
+/*
+ * Journal_head storage management
+ */
+static struct kmem_cache *jbd2_journal_head_cache;
+#ifdef CONFIG_JBD2_DEBUG
+static atomic_t nr_journal_heads = ATOMIC_INIT(0);
+#endif
+
+static int jbd2_journal_init_journal_head_cache(void)
+{
+ int retval;
+
+ J_ASSERT(jbd2_journal_head_cache == NULL);
+ jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
+ sizeof(struct journal_head),
+ 0, /* offset */
+ SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
+ NULL); /* ctor */
+ retval = 0;
+ if (!jbd2_journal_head_cache) {
+ retval = -ENOMEM;
+ printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
+ }
+ return retval;
+}
+
+static void jbd2_journal_destroy_journal_head_cache(void)
+{
+ kmem_cache_destroy(jbd2_journal_head_cache);
+ jbd2_journal_head_cache = NULL;
+}
+
+/*
+ * journal_head splicing and dicing
+ */
+static struct journal_head *journal_alloc_journal_head(void)
+{
+ struct journal_head *ret;
+
+#ifdef CONFIG_JBD2_DEBUG
+ atomic_inc(&nr_journal_heads);
+#endif
+ ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
+ if (!ret) {
+ jbd_debug(1, "out of memory for journal_head\n");
+ pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
+ ret = kmem_cache_zalloc(jbd2_journal_head_cache,
+ GFP_NOFS | __GFP_NOFAIL);
+ }
+ return ret;
+}
+
+static void journal_free_journal_head(struct journal_head *jh)
+{
+#ifdef CONFIG_JBD2_DEBUG
+ atomic_dec(&nr_journal_heads);
+ memset(jh, JBD2_POISON_FREE, sizeof(*jh));
+#endif
+ kmem_cache_free(jbd2_journal_head_cache, jh);
+}
+
+/*
+ * A journal_head is attached to a buffer_head whenever JBD has an
+ * interest in the buffer.
+ *
+ * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
+ * is set. This bit is tested in core kernel code where we need to take
+ * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
+ * there.
+ *
+ * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
+ *
+ * When a buffer has its BH_JBD bit set it is immune from being released by
+ * core kernel code, mainly via ->b_count.
+ *
+ * A journal_head is detached from its buffer_head when the journal_head's
+ * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
+ * transaction (b_cp_transaction) hold their references to b_jcount.
+ *
+ * Various places in the kernel want to attach a journal_head to a buffer_head
+ * _before_ attaching the journal_head to a transaction. To protect the
+ * journal_head in this situation, jbd2_journal_add_journal_head elevates the
+ * journal_head's b_jcount refcount by one. The caller must call
+ * jbd2_journal_put_journal_head() to undo this.
+ *
+ * So the typical usage would be:
+ *
+ * (Attach a journal_head if needed. Increments b_jcount)
+ * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
+ * ...
+ * (Get another reference for transaction)
+ * jbd2_journal_grab_journal_head(bh);
+ * jh->b_transaction = xxx;
+ * (Put original reference)
+ * jbd2_journal_put_journal_head(jh);
+ */
+
+/*
+ * Give a buffer_head a journal_head.
+ *
+ * May sleep.
+ */
+struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
+{
+ struct journal_head *jh;
+ struct journal_head *new_jh = NULL;
+
+repeat:
+ if (!buffer_jbd(bh))
+ new_jh = journal_alloc_journal_head();
+
+ jbd_lock_bh_journal_head(bh);
+ if (buffer_jbd(bh)) {
+ jh = bh2jh(bh);
+ } else {
+ J_ASSERT_BH(bh,
+ (atomic_read(&bh->b_count) > 0) ||
+ (bh->b_page && bh->b_page->mapping));
+
+ if (!new_jh) {
+ jbd_unlock_bh_journal_head(bh);
+ goto repeat;
+ }
+
+ jh = new_jh;
+ new_jh = NULL; /* We consumed it */
+ set_buffer_jbd(bh);
+ bh->b_private = jh;
+ jh->b_bh = bh;
+ get_bh(bh);
+ BUFFER_TRACE(bh, "added journal_head");
+ }
+ jh->b_jcount++;
+ jbd_unlock_bh_journal_head(bh);
+ if (new_jh)
+ journal_free_journal_head(new_jh);
+ return bh->b_private;
+}
+
+/*
+ * Grab a ref against this buffer_head's journal_head. If it ended up not
+ * having a journal_head, return NULL
+ */
+struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
+{
+ struct journal_head *jh = NULL;
+
+ jbd_lock_bh_journal_head(bh);
+ if (buffer_jbd(bh)) {
+ jh = bh2jh(bh);
+ jh->b_jcount++;
+ }
+ jbd_unlock_bh_journal_head(bh);
+ return jh;
+}
+
+static void __journal_remove_journal_head(struct buffer_head *bh)
+{
+ struct journal_head *jh = bh2jh(bh);
+
+ J_ASSERT_JH(jh, jh->b_jcount >= 0);
+ J_ASSERT_JH(jh, jh->b_transaction == NULL);
+ J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+ J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
+ J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
+ J_ASSERT_BH(bh, buffer_jbd(bh));
+ J_ASSERT_BH(bh, jh2bh(jh) == bh);
+ BUFFER_TRACE(bh, "remove journal_head");
+ if (jh->b_frozen_data) {
+ printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
+ jbd2_free(jh->b_frozen_data, bh->b_size);
+ }
+ if (jh->b_committed_data) {
+ printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
+ jbd2_free(jh->b_committed_data, bh->b_size);
+ }
+ bh->b_private = NULL;
+ jh->b_bh = NULL; /* debug, really */
+ clear_buffer_jbd(bh);
+ journal_free_journal_head(jh);
+}
+
+/*
+ * Drop a reference on the passed journal_head. If it fell to zero then
+ * release the journal_head from the buffer_head.
+ */
+void jbd2_journal_put_journal_head(struct journal_head *jh)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd_lock_bh_journal_head(bh);
+ J_ASSERT_JH(jh, jh->b_jcount > 0);
+ --jh->b_jcount;
+ if (!jh->b_jcount) {
+ __journal_remove_journal_head(bh);
+ jbd_unlock_bh_journal_head(bh);
+ __brelse(bh);
+ } else
+ jbd_unlock_bh_journal_head(bh);
+}
+
+/*
+ * Initialize jbd inode head
+ */
+void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
+{
+ jinode->i_transaction = NULL;
+ jinode->i_next_transaction = NULL;
+ jinode->i_vfs_inode = inode;
+ jinode->i_flags = 0;
+ INIT_LIST_HEAD(&jinode->i_list);
+}
+
+/*
+ * Function to be called before we start removing inode from memory (i.e.,
+ * clear_inode() is a fine place to be called from). It removes inode from
+ * transaction's lists.
+ */
+void jbd2_journal_release_jbd_inode(journal_t *journal,
+ struct jbd2_inode *jinode)
+{
+ if (!journal)
+ return;
+restart:
+ spin_lock(&journal->j_list_lock);
+ /* Is commit writing out inode - we have to wait */
+ if (jinode->i_flags & JI_COMMIT_RUNNING) {
+ wait_queue_head_t *wq;
+ DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
+ wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
+ prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&journal->j_list_lock);
+ schedule();
+ finish_wait(wq, &wait.wq_entry);
+ goto restart;
+ }
+
+ if (jinode->i_transaction) {
+ list_del(&jinode->i_list);
+ jinode->i_transaction = NULL;
+ }
+ spin_unlock(&journal->j_list_lock);
+}
+
+
+#ifdef CONFIG_PROC_FS
+
+#define JBD2_STATS_PROC_NAME "fs/jbd2"
+
+static void __init jbd2_create_jbd_stats_proc_entry(void)
+{
+ proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
+}
+
+static void __exit jbd2_remove_jbd_stats_proc_entry(void)
+{
+ if (proc_jbd2_stats)
+ remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
+}
+
+#else
+
+#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
+#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
+
+#endif
+
+struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
+
+static int __init jbd2_journal_init_handle_cache(void)
+{
+ jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
+ if (jbd2_handle_cache == NULL) {
+ printk(KERN_EMERG "JBD2: failed to create handle cache\n");
+ return -ENOMEM;
+ }
+ jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
+ if (jbd2_inode_cache == NULL) {
+ printk(KERN_EMERG "JBD2: failed to create inode cache\n");
+ kmem_cache_destroy(jbd2_handle_cache);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static void jbd2_journal_destroy_handle_cache(void)
+{
+ kmem_cache_destroy(jbd2_handle_cache);
+ jbd2_handle_cache = NULL;
+ kmem_cache_destroy(jbd2_inode_cache);
+ jbd2_inode_cache = NULL;
+}
+
+/*
+ * Module startup and shutdown
+ */
+
+static int __init journal_init_caches(void)
+{
+ int ret;
+
+ ret = jbd2_journal_init_revoke_caches();
+ if (ret == 0)
+ ret = jbd2_journal_init_journal_head_cache();
+ if (ret == 0)
+ ret = jbd2_journal_init_handle_cache();
+ if (ret == 0)
+ ret = jbd2_journal_init_transaction_cache();
+ return ret;
+}
+
+static void jbd2_journal_destroy_caches(void)
+{
+ jbd2_journal_destroy_revoke_caches();
+ jbd2_journal_destroy_journal_head_cache();
+ jbd2_journal_destroy_handle_cache();
+ jbd2_journal_destroy_transaction_cache();
+ jbd2_journal_destroy_slabs();
+}
+
+static int __init journal_init(void)
+{
+ int ret;
+
+ BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
+
+ ret = journal_init_caches();
+ if (ret == 0) {
+ jbd2_create_jbd_stats_proc_entry();
+ } else {
+ jbd2_journal_destroy_caches();
+ }
+ return ret;
+}
+
+static void __exit journal_exit(void)
+{
+#ifdef CONFIG_JBD2_DEBUG
+ int n = atomic_read(&nr_journal_heads);
+ if (n)
+ printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
+#endif
+ jbd2_remove_jbd_stats_proc_entry();
+ jbd2_journal_destroy_caches();
+}
+
+MODULE_LICENSE("GPL");
+module_init(journal_init);
+module_exit(journal_exit);
+
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
new file mode 100644
index 0000000..a4967b2
--- /dev/null
+++ b/fs/jbd2/recovery.c
@@ -0,0 +1,852 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/recovery.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1999-2000 Red Hat Software --- All Rights Reserved
+ *
+ * Journal recovery routines for the generic filesystem journaling code;
+ * part of the ext2fs journaling system.
+ */
+
+#ifndef __KERNEL__
+#include "jfs_user.h"
+#else
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/crc32.h>
+#include <linux/blkdev.h>
+#endif
+
+/*
+ * Maintain information about the progress of the recovery job, so that
+ * the different passes can carry information between them.
+ */
+struct recovery_info
+{
+ tid_t start_transaction;
+ tid_t end_transaction;
+
+ int nr_replays;
+ int nr_revokes;
+ int nr_revoke_hits;
+};
+
+enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
+static int do_one_pass(journal_t *journal,
+ struct recovery_info *info, enum passtype pass);
+static int scan_revoke_records(journal_t *, struct buffer_head *,
+ tid_t, struct recovery_info *);
+
+#ifdef __KERNEL__
+
+/* Release readahead buffers after use */
+static void journal_brelse_array(struct buffer_head *b[], int n)
+{
+ while (--n >= 0)
+ brelse (b[n]);
+}
+
+
+/*
+ * When reading from the journal, we are going through the block device
+ * layer directly and so there is no readahead being done for us. We
+ * need to implement any readahead ourselves if we want it to happen at
+ * all. Recovery is basically one long sequential read, so make sure we
+ * do the IO in reasonably large chunks.
+ *
+ * This is not so critical that we need to be enormously clever about
+ * the readahead size, though. 128K is a purely arbitrary, good-enough
+ * fixed value.
+ */
+
+#define MAXBUF 8
+static int do_readahead(journal_t *journal, unsigned int start)
+{
+ int err;
+ unsigned int max, nbufs, next;
+ unsigned long long blocknr;
+ struct buffer_head *bh;
+
+ struct buffer_head * bufs[MAXBUF];
+
+ /* Do up to 128K of readahead */
+ max = start + (128 * 1024 / journal->j_blocksize);
+ if (max > journal->j_maxlen)
+ max = journal->j_maxlen;
+
+ /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
+ * a time to the block device IO layer. */
+
+ nbufs = 0;
+
+ for (next = start; next < max; next++) {
+ err = jbd2_journal_bmap(journal, next, &blocknr);
+
+ if (err) {
+ printk(KERN_ERR "JBD2: bad block at offset %u\n",
+ next);
+ goto failed;
+ }
+
+ bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+ if (!bh) {
+ err = -ENOMEM;
+ goto failed;
+ }
+
+ if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
+ bufs[nbufs++] = bh;
+ if (nbufs == MAXBUF) {
+ ll_rw_block(REQ_OP_READ, 0, nbufs, bufs);
+ journal_brelse_array(bufs, nbufs);
+ nbufs = 0;
+ }
+ } else
+ brelse(bh);
+ }
+
+ if (nbufs)
+ ll_rw_block(REQ_OP_READ, 0, nbufs, bufs);
+ err = 0;
+
+failed:
+ if (nbufs)
+ journal_brelse_array(bufs, nbufs);
+ return err;
+}
+
+#endif /* __KERNEL__ */
+
+
+/*
+ * Read a block from the journal
+ */
+
+static int jread(struct buffer_head **bhp, journal_t *journal,
+ unsigned int offset)
+{
+ int err;
+ unsigned long long blocknr;
+ struct buffer_head *bh;
+
+ *bhp = NULL;
+
+ if (offset >= journal->j_maxlen) {
+ printk(KERN_ERR "JBD2: corrupted journal superblock\n");
+ return -EFSCORRUPTED;
+ }
+
+ err = jbd2_journal_bmap(journal, offset, &blocknr);
+
+ if (err) {
+ printk(KERN_ERR "JBD2: bad block at offset %u\n",
+ offset);
+ return err;
+ }
+
+ bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
+ if (!bh)
+ return -ENOMEM;
+
+ if (!buffer_uptodate(bh)) {
+ /* If this is a brand new buffer, start readahead.
+ Otherwise, we assume we are already reading it. */
+ if (!buffer_req(bh))
+ do_readahead(journal, offset);
+ wait_on_buffer(bh);
+ }
+
+ if (!buffer_uptodate(bh)) {
+ printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
+ offset);
+ brelse(bh);
+ return -EIO;
+ }
+
+ *bhp = bh;
+ return 0;
+}
+
+static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
+{
+ struct jbd2_journal_block_tail *tail;
+ __be32 provided;
+ __u32 calculated;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return 1;
+
+ tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize -
+ sizeof(struct jbd2_journal_block_tail));
+ provided = tail->t_checksum;
+ tail->t_checksum = 0;
+ calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+ tail->t_checksum = provided;
+
+ return provided == cpu_to_be32(calculated);
+}
+
+/*
+ * Count the number of in-use tags in a journal descriptor block.
+ */
+
+static int count_tags(journal_t *journal, struct buffer_head *bh)
+{
+ char * tagp;
+ journal_block_tag_t * tag;
+ int nr = 0, size = journal->j_blocksize;
+ int tag_bytes = journal_tag_bytes(journal);
+
+ if (jbd2_journal_has_csum_v2or3(journal))
+ size -= sizeof(struct jbd2_journal_block_tail);
+
+ tagp = &bh->b_data[sizeof(journal_header_t)];
+
+ while ((tagp - bh->b_data + tag_bytes) <= size) {
+ tag = (journal_block_tag_t *) tagp;
+
+ nr++;
+ tagp += tag_bytes;
+ if (!(tag->t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))
+ tagp += 16;
+
+ if (tag->t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))
+ break;
+ }
+
+ return nr;
+}
+
+
+/* Make sure we wrap around the log correctly! */
+#define wrap(journal, var) \
+do { \
+ if (var >= (journal)->j_last) \
+ var -= ((journal)->j_last - (journal)->j_first); \
+} while (0)
+
+/**
+ * jbd2_journal_recover - recovers a on-disk journal
+ * @journal: the journal to recover
+ *
+ * The primary function for recovering the log contents when mounting a
+ * journaled device.
+ *
+ * Recovery is done in three passes. In the first pass, we look for the
+ * end of the log. In the second, we assemble the list of revoke
+ * blocks. In the third and final pass, we replay any un-revoked blocks
+ * in the log.
+ */
+int jbd2_journal_recover(journal_t *journal)
+{
+ int err, err2;
+ journal_superblock_t * sb;
+
+ struct recovery_info info;
+
+ memset(&info, 0, sizeof(info));
+ sb = journal->j_superblock;
+
+ /*
+ * The journal superblock's s_start field (the current log head)
+ * is always zero if, and only if, the journal was cleanly
+ * unmounted.
+ */
+
+ if (!sb->s_start) {
+ jbd_debug(1, "No recovery required, last transaction %d\n",
+ be32_to_cpu(sb->s_sequence));
+ journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
+ return 0;
+ }
+
+ err = do_one_pass(journal, &info, PASS_SCAN);
+ if (!err)
+ err = do_one_pass(journal, &info, PASS_REVOKE);
+ if (!err)
+ err = do_one_pass(journal, &info, PASS_REPLAY);
+
+ jbd_debug(1, "JBD2: recovery, exit status %d, "
+ "recovered transactions %u to %u\n",
+ err, info.start_transaction, info.end_transaction);
+ jbd_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
+ info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
+
+ /* Restart the log at the next transaction ID, thus invalidating
+ * any existing commit records in the log. */
+ journal->j_transaction_sequence = ++info.end_transaction;
+
+ jbd2_journal_clear_revoke(journal);
+ err2 = sync_blockdev(journal->j_fs_dev);
+ if (!err)
+ err = err2;
+ /* Make sure all replayed data is on permanent storage */
+ if (journal->j_flags & JBD2_BARRIER) {
+ err2 = blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
+ if (!err)
+ err = err2;
+ }
+ return err;
+}
+
+/**
+ * jbd2_journal_skip_recovery - Start journal and wipe exiting records
+ * @journal: journal to startup
+ *
+ * Locate any valid recovery information from the journal and set up the
+ * journal structures in memory to ignore it (presumably because the
+ * caller has evidence that it is out of date).
+ * This function doesn't appear to be exported..
+ *
+ * We perform one pass over the journal to allow us to tell the user how
+ * much recovery information is being erased, and to let us initialise
+ * the journal transaction sequence numbers to the next unused ID.
+ */
+int jbd2_journal_skip_recovery(journal_t *journal)
+{
+ int err;
+
+ struct recovery_info info;
+
+ memset (&info, 0, sizeof(info));
+
+ err = do_one_pass(journal, &info, PASS_SCAN);
+
+ if (err) {
+ printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
+ ++journal->j_transaction_sequence;
+ } else {
+#ifdef CONFIG_JBD2_DEBUG
+ int dropped = info.end_transaction -
+ be32_to_cpu(journal->j_superblock->s_sequence);
+ jbd_debug(1,
+ "JBD2: ignoring %d transaction%s from the journal.\n",
+ dropped, (dropped == 1) ? "" : "s");
+#endif
+ journal->j_transaction_sequence = ++info.end_transaction;
+ }
+
+ journal->j_tail = 0;
+ return err;
+}
+
+static inline unsigned long long read_tag_block(journal_t *journal,
+ journal_block_tag_t *tag)
+{
+ unsigned long long block = be32_to_cpu(tag->t_blocknr);
+ if (jbd2_has_feature_64bit(journal))
+ block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
+ return block;
+}
+
+/*
+ * calc_chksums calculates the checksums for the blocks described in the
+ * descriptor block.
+ */
+static int calc_chksums(journal_t *journal, struct buffer_head *bh,
+ unsigned long *next_log_block, __u32 *crc32_sum)
+{
+ int i, num_blks, err;
+ unsigned long io_block;
+ struct buffer_head *obh;
+
+ num_blks = count_tags(journal, bh);
+ /* Calculate checksum of the descriptor block. */
+ *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
+
+ for (i = 0; i < num_blks; i++) {
+ io_block = (*next_log_block)++;
+ wrap(journal, *next_log_block);
+ err = jread(&obh, journal, io_block);
+ if (err) {
+ printk(KERN_ERR "JBD2: IO error %d recovering block "
+ "%lu in log\n", err, io_block);
+ return 1;
+ } else {
+ *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
+ obh->b_size);
+ }
+ put_bh(obh);
+ }
+ return 0;
+}
+
+static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
+{
+ struct commit_header *h;
+ __be32 provided;
+ __u32 calculated;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return 1;
+
+ h = buf;
+ provided = h->h_chksum[0];
+ h->h_chksum[0] = 0;
+ calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+ h->h_chksum[0] = provided;
+
+ return provided == cpu_to_be32(calculated);
+}
+
+static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
+ void *buf, __u32 sequence)
+{
+ journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
+ __u32 csum32;
+ __be32 seq;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return 1;
+
+ seq = cpu_to_be32(sequence);
+ csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
+ csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
+
+ if (jbd2_has_feature_csum3(j))
+ return tag3->t_checksum == cpu_to_be32(csum32);
+ else
+ return tag->t_checksum == cpu_to_be16(csum32);
+}
+
+static int do_one_pass(journal_t *journal,
+ struct recovery_info *info, enum passtype pass)
+{
+ unsigned int first_commit_ID, next_commit_ID;
+ unsigned long next_log_block;
+ int err, success = 0;
+ journal_superblock_t * sb;
+ journal_header_t * tmp;
+ struct buffer_head * bh;
+ unsigned int sequence;
+ int blocktype;
+ int tag_bytes = journal_tag_bytes(journal);
+ __u32 crc32_sum = ~0; /* Transactional Checksums */
+ int descr_csum_size = 0;
+ int block_error = 0;
+
+ /*
+ * First thing is to establish what we expect to find in the log
+ * (in terms of transaction IDs), and where (in terms of log
+ * block offsets): query the superblock.
+ */
+
+ sb = journal->j_superblock;
+ next_commit_ID = be32_to_cpu(sb->s_sequence);
+ next_log_block = be32_to_cpu(sb->s_start);
+
+ first_commit_ID = next_commit_ID;
+ if (pass == PASS_SCAN)
+ info->start_transaction = first_commit_ID;
+
+ jbd_debug(1, "Starting recovery pass %d\n", pass);
+
+ /*
+ * Now we walk through the log, transaction by transaction,
+ * making sure that each transaction has a commit block in the
+ * expected place. Each complete transaction gets replayed back
+ * into the main filesystem.
+ */
+
+ while (1) {
+ int flags;
+ char * tagp;
+ journal_block_tag_t * tag;
+ struct buffer_head * obh;
+ struct buffer_head * nbh;
+
+ cond_resched();
+
+ /* If we already know where to stop the log traversal,
+ * check right now that we haven't gone past the end of
+ * the log. */
+
+ if (pass != PASS_SCAN)
+ if (tid_geq(next_commit_ID, info->end_transaction))
+ break;
+
+ jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
+ next_commit_ID, next_log_block, journal->j_last);
+
+ /* Skip over each chunk of the transaction looking
+ * either the next descriptor block or the final commit
+ * record. */
+
+ jbd_debug(3, "JBD2: checking block %ld\n", next_log_block);
+ err = jread(&bh, journal, next_log_block);
+ if (err)
+ goto failed;
+
+ next_log_block++;
+ wrap(journal, next_log_block);
+
+ /* What kind of buffer is it?
+ *
+ * If it is a descriptor block, check that it has the
+ * expected sequence number. Otherwise, we're all done
+ * here. */
+
+ tmp = (journal_header_t *)bh->b_data;
+
+ if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
+ brelse(bh);
+ break;
+ }
+
+ blocktype = be32_to_cpu(tmp->h_blocktype);
+ sequence = be32_to_cpu(tmp->h_sequence);
+ jbd_debug(3, "Found magic %d, sequence %d\n",
+ blocktype, sequence);
+
+ if (sequence != next_commit_ID) {
+ brelse(bh);
+ break;
+ }
+
+ /* OK, we have a valid descriptor block which matches
+ * all of the sequence number checks. What are we going
+ * to do with it? That depends on the pass... */
+
+ switch(blocktype) {
+ case JBD2_DESCRIPTOR_BLOCK:
+ /* Verify checksum first */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ descr_csum_size =
+ sizeof(struct jbd2_journal_block_tail);
+ if (descr_csum_size > 0 &&
+ !jbd2_descriptor_block_csum_verify(journal,
+ bh->b_data)) {
+ printk(KERN_ERR "JBD2: Invalid checksum "
+ "recovering block %lu in log\n",
+ next_log_block);
+ err = -EFSBADCRC;
+ brelse(bh);
+ goto failed;
+ }
+
+ /* If it is a valid descriptor block, replay it
+ * in pass REPLAY; if journal_checksums enabled, then
+ * calculate checksums in PASS_SCAN, otherwise,
+ * just skip over the blocks it describes. */
+ if (pass != PASS_REPLAY) {
+ if (pass == PASS_SCAN &&
+ jbd2_has_feature_checksum(journal) &&
+ !info->end_transaction) {
+ if (calc_chksums(journal, bh,
+ &next_log_block,
+ &crc32_sum)) {
+ put_bh(bh);
+ break;
+ }
+ put_bh(bh);
+ continue;
+ }
+ next_log_block += count_tags(journal, bh);
+ wrap(journal, next_log_block);
+ put_bh(bh);
+ continue;
+ }
+
+ /* A descriptor block: we can now write all of
+ * the data blocks. Yay, useful work is finally
+ * getting done here! */
+
+ tagp = &bh->b_data[sizeof(journal_header_t)];
+ while ((tagp - bh->b_data + tag_bytes)
+ <= journal->j_blocksize - descr_csum_size) {
+ unsigned long io_block;
+
+ tag = (journal_block_tag_t *) tagp;
+ flags = be16_to_cpu(tag->t_flags);
+
+ io_block = next_log_block++;
+ wrap(journal, next_log_block);
+ err = jread(&obh, journal, io_block);
+ if (err) {
+ /* Recover what we can, but
+ * report failure at the end. */
+ success = err;
+ printk(KERN_ERR
+ "JBD2: IO error %d recovering "
+ "block %ld in log\n",
+ err, io_block);
+ } else {
+ unsigned long long blocknr;
+
+ J_ASSERT(obh != NULL);
+ blocknr = read_tag_block(journal,
+ tag);
+
+ /* If the block has been
+ * revoked, then we're all done
+ * here. */
+ if (jbd2_journal_test_revoke
+ (journal, blocknr,
+ next_commit_ID)) {
+ brelse(obh);
+ ++info->nr_revoke_hits;
+ goto skip_write;
+ }
+
+ /* Look for block corruption */
+ if (!jbd2_block_tag_csum_verify(
+ journal, tag, obh->b_data,
+ be32_to_cpu(tmp->h_sequence))) {
+ brelse(obh);
+ success = -EFSBADCRC;
+ printk(KERN_ERR "JBD2: Invalid "
+ "checksum recovering "
+ "data block %llu in "
+ "log\n", blocknr);
+ block_error = 1;
+ goto skip_write;
+ }
+
+ /* Find a buffer for the new
+ * data being restored */
+ nbh = __getblk(journal->j_fs_dev,
+ blocknr,
+ journal->j_blocksize);
+ if (nbh == NULL) {
+ printk(KERN_ERR
+ "JBD2: Out of memory "
+ "during recovery.\n");
+ err = -ENOMEM;
+ brelse(bh);
+ brelse(obh);
+ goto failed;
+ }
+
+ lock_buffer(nbh);
+ memcpy(nbh->b_data, obh->b_data,
+ journal->j_blocksize);
+ if (flags & JBD2_FLAG_ESCAPE) {
+ *((__be32 *)nbh->b_data) =
+ cpu_to_be32(JBD2_MAGIC_NUMBER);
+ }
+
+ BUFFER_TRACE(nbh, "marking dirty");
+ set_buffer_uptodate(nbh);
+ mark_buffer_dirty(nbh);
+ BUFFER_TRACE(nbh, "marking uptodate");
+ ++info->nr_replays;
+ /* ll_rw_block(WRITE, 1, &nbh); */
+ unlock_buffer(nbh);
+ brelse(obh);
+ brelse(nbh);
+ }
+
+ skip_write:
+ tagp += tag_bytes;
+ if (!(flags & JBD2_FLAG_SAME_UUID))
+ tagp += 16;
+
+ if (flags & JBD2_FLAG_LAST_TAG)
+ break;
+ }
+
+ brelse(bh);
+ continue;
+
+ case JBD2_COMMIT_BLOCK:
+ /* How to differentiate between interrupted commit
+ * and journal corruption ?
+ *
+ * {nth transaction}
+ * Checksum Verification Failed
+ * |
+ * ____________________
+ * | |
+ * async_commit sync_commit
+ * | |
+ * | GO TO NEXT "Journal Corruption"
+ * | TRANSACTION
+ * |
+ * {(n+1)th transanction}
+ * |
+ * _______|______________
+ * | |
+ * Commit block found Commit block not found
+ * | |
+ * "Journal Corruption" |
+ * _____________|_________
+ * | |
+ * nth trans corrupt OR nth trans
+ * and (n+1)th interrupted interrupted
+ * before commit block
+ * could reach the disk.
+ * (Cannot find the difference in above
+ * mentioned conditions. Hence assume
+ * "Interrupted Commit".)
+ */
+
+ /* Found an expected commit block: if checksums
+ * are present verify them in PASS_SCAN; else not
+ * much to do other than move on to the next sequence
+ * number. */
+ if (pass == PASS_SCAN &&
+ jbd2_has_feature_checksum(journal)) {
+ int chksum_err, chksum_seen;
+ struct commit_header *cbh =
+ (struct commit_header *)bh->b_data;
+ unsigned found_chksum =
+ be32_to_cpu(cbh->h_chksum[0]);
+
+ chksum_err = chksum_seen = 0;
+
+ if (info->end_transaction) {
+ journal->j_failed_commit =
+ info->end_transaction;
+ brelse(bh);
+ break;
+ }
+
+ if (crc32_sum == found_chksum &&
+ cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
+ cbh->h_chksum_size ==
+ JBD2_CRC32_CHKSUM_SIZE)
+ chksum_seen = 1;
+ else if (!(cbh->h_chksum_type == 0 &&
+ cbh->h_chksum_size == 0 &&
+ found_chksum == 0 &&
+ !chksum_seen))
+ /*
+ * If fs is mounted using an old kernel and then
+ * kernel with journal_chksum is used then we
+ * get a situation where the journal flag has
+ * checksum flag set but checksums are not
+ * present i.e chksum = 0, in the individual
+ * commit blocks.
+ * Hence to avoid checksum failures, in this
+ * situation, this extra check is added.
+ */
+ chksum_err = 1;
+
+ if (chksum_err) {
+ info->end_transaction = next_commit_ID;
+
+ if (!jbd2_has_feature_async_commit(journal)) {
+ journal->j_failed_commit =
+ next_commit_ID;
+ brelse(bh);
+ break;
+ }
+ }
+ crc32_sum = ~0;
+ }
+ if (pass == PASS_SCAN &&
+ !jbd2_commit_block_csum_verify(journal,
+ bh->b_data)) {
+ info->end_transaction = next_commit_ID;
+
+ if (!jbd2_has_feature_async_commit(journal)) {
+ journal->j_failed_commit =
+ next_commit_ID;
+ brelse(bh);
+ break;
+ }
+ }
+ brelse(bh);
+ next_commit_ID++;
+ continue;
+
+ case JBD2_REVOKE_BLOCK:
+ /* If we aren't in the REVOKE pass, then we can
+ * just skip over this block. */
+ if (pass != PASS_REVOKE) {
+ brelse(bh);
+ continue;
+ }
+
+ err = scan_revoke_records(journal, bh,
+ next_commit_ID, info);
+ brelse(bh);
+ if (err)
+ goto failed;
+ continue;
+
+ default:
+ jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
+ blocktype);
+ brelse(bh);
+ goto done;
+ }
+ }
+
+ done:
+ /*
+ * We broke out of the log scan loop: either we came to the
+ * known end of the log or we found an unexpected block in the
+ * log. If the latter happened, then we know that the "current"
+ * transaction marks the end of the valid log.
+ */
+
+ if (pass == PASS_SCAN) {
+ if (!info->end_transaction)
+ info->end_transaction = next_commit_ID;
+ } else {
+ /* It's really bad news if different passes end up at
+ * different places (but possible due to IO errors). */
+ if (info->end_transaction != next_commit_ID) {
+ printk(KERN_ERR "JBD2: recovery pass %d ended at "
+ "transaction %u, expected %u\n",
+ pass, next_commit_ID, info->end_transaction);
+ if (!success)
+ success = -EIO;
+ }
+ }
+ if (block_error && success == 0)
+ success = -EIO;
+ return success;
+
+ failed:
+ return err;
+}
+
+/* Scan a revoke record, marking all blocks mentioned as revoked. */
+
+static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
+ tid_t sequence, struct recovery_info *info)
+{
+ jbd2_journal_revoke_header_t *header;
+ int offset, max;
+ int csum_size = 0;
+ __u32 rcount;
+ int record_len = 4;
+
+ header = (jbd2_journal_revoke_header_t *) bh->b_data;
+ offset = sizeof(jbd2_journal_revoke_header_t);
+ rcount = be32_to_cpu(header->r_count);
+
+ if (!jbd2_descriptor_block_csum_verify(journal, header))
+ return -EFSBADCRC;
+
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
+ if (rcount > journal->j_blocksize - csum_size)
+ return -EINVAL;
+ max = rcount;
+
+ if (jbd2_has_feature_64bit(journal))
+ record_len = 8;
+
+ while (offset + record_len <= max) {
+ unsigned long long blocknr;
+ int err;
+
+ if (record_len == 4)
+ blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
+ else
+ blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
+ offset += record_len;
+ err = jbd2_journal_set_revoke(journal, blocknr, sequence);
+ if (err)
+ return err;
+ ++info->nr_revokes;
+ }
+ return 0;
+}
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
new file mode 100644
index 0000000..a1143e5
--- /dev/null
+++ b/fs/jbd2/revoke.c
@@ -0,0 +1,731 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/revoke.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 2000
+ *
+ * Copyright 2000 Red Hat corp --- All Rights Reserved
+ *
+ * Journal revoke routines for the generic filesystem journaling code;
+ * part of the ext2fs journaling system.
+ *
+ * Revoke is the mechanism used to prevent old log records for deleted
+ * metadata from being replayed on top of newer data using the same
+ * blocks. The revoke mechanism is used in two separate places:
+ *
+ * + Commit: during commit we write the entire list of the current
+ * transaction's revoked blocks to the journal
+ *
+ * + Recovery: during recovery we record the transaction ID of all
+ * revoked blocks. If there are multiple revoke records in the log
+ * for a single block, only the last one counts, and if there is a log
+ * entry for a block beyond the last revoke, then that log entry still
+ * gets replayed.
+ *
+ * We can get interactions between revokes and new log data within a
+ * single transaction:
+ *
+ * Block is revoked and then journaled:
+ * The desired end result is the journaling of the new block, so we
+ * cancel the revoke before the transaction commits.
+ *
+ * Block is journaled and then revoked:
+ * The revoke must take precedence over the write of the block, so we
+ * need either to cancel the journal entry or to write the revoke
+ * later in the log than the log block. In this case, we choose the
+ * latter: journaling a block cancels any revoke record for that block
+ * in the current transaction, so any revoke for that block in the
+ * transaction must have happened after the block was journaled and so
+ * the revoke must take precedence.
+ *
+ * Block is revoked and then written as data:
+ * The data write is allowed to succeed, but the revoke is _not_
+ * cancelled. We still need to prevent old log records from
+ * overwriting the new data. We don't even need to clear the revoke
+ * bit here.
+ *
+ * We cache revoke status of a buffer in the current transaction in b_states
+ * bits. As the name says, revokevalid flag indicates that the cached revoke
+ * status of a buffer is valid and we can rely on the cached status.
+ *
+ * Revoke information on buffers is a tri-state value:
+ *
+ * RevokeValid clear: no cached revoke status, need to look it up
+ * RevokeValid set, Revoked clear:
+ * buffer has not been revoked, and cancel_revoke
+ * need do nothing.
+ * RevokeValid set, Revoked set:
+ * buffer has been revoked.
+ *
+ * Locking rules:
+ * We keep two hash tables of revoke records. One hashtable belongs to the
+ * running transaction (is pointed to by journal->j_revoke), the other one
+ * belongs to the committing transaction. Accesses to the second hash table
+ * happen only from the kjournald and no other thread touches this table. Also
+ * journal_switch_revoke_table() which switches which hashtable belongs to the
+ * running and which to the committing transaction is called only from
+ * kjournald. Therefore we need no locks when accessing the hashtable belonging
+ * to the committing transaction.
+ *
+ * All users operating on the hash table belonging to the running transaction
+ * have a handle to the transaction. Therefore they are safe from kjournald
+ * switching hash tables under them. For operations on the lists of entries in
+ * the hash table j_revoke_lock is used.
+ *
+ * Finally, also replay code uses the hash tables but at this moment no one else
+ * can touch them (filesystem isn't mounted yet) and hence no locking is
+ * needed.
+ */
+
+#ifndef __KERNEL__
+#include "jfs_user.h"
+#else
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/log2.h>
+#include <linux/hash.h>
+#endif
+
+static struct kmem_cache *jbd2_revoke_record_cache;
+static struct kmem_cache *jbd2_revoke_table_cache;
+
+/* Each revoke record represents one single revoked block. During
+ journal replay, this involves recording the transaction ID of the
+ last transaction to revoke this block. */
+
+struct jbd2_revoke_record_s
+{
+ struct list_head hash;
+ tid_t sequence; /* Used for recovery only */
+ unsigned long long blocknr;
+};
+
+
+/* The revoke table is just a simple hash table of revoke records. */
+struct jbd2_revoke_table_s
+{
+ /* It is conceivable that we might want a larger hash table
+ * for recovery. Must be a power of two. */
+ int hash_size;
+ int hash_shift;
+ struct list_head *hash_table;
+};
+
+
+#ifdef __KERNEL__
+static void write_one_revoke_record(transaction_t *,
+ struct list_head *,
+ struct buffer_head **, int *,
+ struct jbd2_revoke_record_s *);
+static void flush_descriptor(journal_t *, struct buffer_head *, int);
+#endif
+
+/* Utility functions to maintain the revoke table */
+
+static inline int hash(journal_t *journal, unsigned long long block)
+{
+ return hash_64(block, journal->j_revoke->hash_shift);
+}
+
+static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
+ tid_t seq)
+{
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+ gfp_t gfp_mask = GFP_NOFS;
+
+ if (journal_oom_retry)
+ gfp_mask |= __GFP_NOFAIL;
+ record = kmem_cache_alloc(jbd2_revoke_record_cache, gfp_mask);
+ if (!record)
+ return -ENOMEM;
+
+ record->sequence = seq;
+ record->blocknr = blocknr;
+ hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
+ spin_lock(&journal->j_revoke_lock);
+ list_add(&record->hash, hash_list);
+ spin_unlock(&journal->j_revoke_lock);
+ return 0;
+}
+
+/* Find a revoke record in the journal's hash table. */
+
+static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
+ unsigned long long blocknr)
+{
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+
+ hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
+
+ spin_lock(&journal->j_revoke_lock);
+ record = (struct jbd2_revoke_record_s *) hash_list->next;
+ while (&(record->hash) != hash_list) {
+ if (record->blocknr == blocknr) {
+ spin_unlock(&journal->j_revoke_lock);
+ return record;
+ }
+ record = (struct jbd2_revoke_record_s *) record->hash.next;
+ }
+ spin_unlock(&journal->j_revoke_lock);
+ return NULL;
+}
+
+void jbd2_journal_destroy_revoke_caches(void)
+{
+ kmem_cache_destroy(jbd2_revoke_record_cache);
+ jbd2_revoke_record_cache = NULL;
+ kmem_cache_destroy(jbd2_revoke_table_cache);
+ jbd2_revoke_table_cache = NULL;
+}
+
+int __init jbd2_journal_init_revoke_caches(void)
+{
+ J_ASSERT(!jbd2_revoke_record_cache);
+ J_ASSERT(!jbd2_revoke_table_cache);
+
+ jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
+ SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
+ if (!jbd2_revoke_record_cache)
+ goto record_cache_failure;
+
+ jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
+ SLAB_TEMPORARY);
+ if (!jbd2_revoke_table_cache)
+ goto table_cache_failure;
+ return 0;
+table_cache_failure:
+ jbd2_journal_destroy_revoke_caches();
+record_cache_failure:
+ return -ENOMEM;
+}
+
+static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
+{
+ int shift = 0;
+ int tmp = hash_size;
+ struct jbd2_revoke_table_s *table;
+
+ table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
+ if (!table)
+ goto out;
+
+ while((tmp >>= 1UL) != 0UL)
+ shift++;
+
+ table->hash_size = hash_size;
+ table->hash_shift = shift;
+ table->hash_table =
+ kmalloc_array(hash_size, sizeof(struct list_head), GFP_KERNEL);
+ if (!table->hash_table) {
+ kmem_cache_free(jbd2_revoke_table_cache, table);
+ table = NULL;
+ goto out;
+ }
+
+ for (tmp = 0; tmp < hash_size; tmp++)
+ INIT_LIST_HEAD(&table->hash_table[tmp]);
+
+out:
+ return table;
+}
+
+static void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table)
+{
+ int i;
+ struct list_head *hash_list;
+
+ for (i = 0; i < table->hash_size; i++) {
+ hash_list = &table->hash_table[i];
+ J_ASSERT(list_empty(hash_list));
+ }
+
+ kfree(table->hash_table);
+ kmem_cache_free(jbd2_revoke_table_cache, table);
+}
+
+/* Initialise the revoke table for a given journal to a given size. */
+int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
+{
+ J_ASSERT(journal->j_revoke_table[0] == NULL);
+ J_ASSERT(is_power_of_2(hash_size));
+
+ journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[0])
+ goto fail0;
+
+ journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[1])
+ goto fail1;
+
+ journal->j_revoke = journal->j_revoke_table[1];
+
+ spin_lock_init(&journal->j_revoke_lock);
+
+ return 0;
+
+fail1:
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
+ journal->j_revoke_table[0] = NULL;
+fail0:
+ return -ENOMEM;
+}
+
+/* Destroy a journal's revoke table. The table must already be empty! */
+void jbd2_journal_destroy_revoke(journal_t *journal)
+{
+ journal->j_revoke = NULL;
+ if (journal->j_revoke_table[0])
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
+ if (journal->j_revoke_table[1])
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]);
+}
+
+
+#ifdef __KERNEL__
+
+/*
+ * jbd2_journal_revoke: revoke a given buffer_head from the journal. This
+ * prevents the block from being replayed during recovery if we take a
+ * crash after this current transaction commits. Any subsequent
+ * metadata writes of the buffer in this transaction cancel the
+ * revoke.
+ *
+ * Note that this call may block --- it is up to the caller to make
+ * sure that there are no further calls to journal_write_metadata
+ * before the revoke is complete. In ext3, this implies calling the
+ * revoke before clearing the block bitmap when we are deleting
+ * metadata.
+ *
+ * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a
+ * parameter, but does _not_ forget the buffer_head if the bh was only
+ * found implicitly.
+ *
+ * bh_in may not be a journalled buffer - it may have come off
+ * the hash tables without an attached journal_head.
+ *
+ * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count
+ * by one.
+ */
+
+int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
+ struct buffer_head *bh_in)
+{
+ struct buffer_head *bh = NULL;
+ journal_t *journal;
+ struct block_device *bdev;
+ int err;
+
+ might_sleep();
+ if (bh_in)
+ BUFFER_TRACE(bh_in, "enter");
+
+ journal = handle->h_transaction->t_journal;
+ if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){
+ J_ASSERT (!"Cannot set revoke feature!");
+ return -EINVAL;
+ }
+
+ bdev = journal->j_fs_dev;
+ bh = bh_in;
+
+ if (!bh) {
+ bh = __find_get_block(bdev, blocknr, journal->j_blocksize);
+ if (bh)
+ BUFFER_TRACE(bh, "found on hash");
+ }
+#ifdef JBD2_EXPENSIVE_CHECKING
+ else {
+ struct buffer_head *bh2;
+
+ /* If there is a different buffer_head lying around in
+ * memory anywhere... */
+ bh2 = __find_get_block(bdev, blocknr, journal->j_blocksize);
+ if (bh2) {
+ /* ... and it has RevokeValid status... */
+ if (bh2 != bh && buffer_revokevalid(bh2))
+ /* ...then it better be revoked too,
+ * since it's illegal to create a revoke
+ * record against a buffer_head which is
+ * not marked revoked --- that would
+ * risk missing a subsequent revoke
+ * cancel. */
+ J_ASSERT_BH(bh2, buffer_revoked(bh2));
+ put_bh(bh2);
+ }
+ }
+#endif
+
+ /* We really ought not ever to revoke twice in a row without
+ first having the revoke cancelled: it's illegal to free a
+ block twice without allocating it in between! */
+ if (bh) {
+ if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
+ "inconsistent data on disk")) {
+ if (!bh_in)
+ brelse(bh);
+ return -EIO;
+ }
+ set_buffer_revoked(bh);
+ set_buffer_revokevalid(bh);
+ if (bh_in) {
+ BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
+ jbd2_journal_forget(handle, bh_in);
+ } else {
+ BUFFER_TRACE(bh, "call brelse");
+ __brelse(bh);
+ }
+ }
+
+ jbd_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
+ err = insert_revoke_hash(journal, blocknr,
+ handle->h_transaction->t_tid);
+ BUFFER_TRACE(bh_in, "exit");
+ return err;
+}
+
+/*
+ * Cancel an outstanding revoke. For use only internally by the
+ * journaling code (called from jbd2_journal_get_write_access).
+ *
+ * We trust buffer_revoked() on the buffer if the buffer is already
+ * being journaled: if there is no revoke pending on the buffer, then we
+ * don't do anything here.
+ *
+ * This would break if it were possible for a buffer to be revoked and
+ * discarded, and then reallocated within the same transaction. In such
+ * a case we would have lost the revoked bit, but when we arrived here
+ * the second time we would still have a pending revoke to cancel. So,
+ * do not trust the Revoked bit on buffers unless RevokeValid is also
+ * set.
+ */
+int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
+{
+ struct jbd2_revoke_record_s *record;
+ journal_t *journal = handle->h_transaction->t_journal;
+ int need_cancel;
+ int did_revoke = 0; /* akpm: debug */
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd_debug(4, "journal_head %p, cancelling revoke\n", jh);
+
+ /* Is the existing Revoke bit valid? If so, we trust it, and
+ * only perform the full cancel if the revoke bit is set. If
+ * not, we can't trust the revoke bit, and we need to do the
+ * full search for a revoke record. */
+ if (test_set_buffer_revokevalid(bh)) {
+ need_cancel = test_clear_buffer_revoked(bh);
+ } else {
+ need_cancel = 1;
+ clear_buffer_revoked(bh);
+ }
+
+ if (need_cancel) {
+ record = find_revoke_record(journal, bh->b_blocknr);
+ if (record) {
+ jbd_debug(4, "cancelled existing revoke on "
+ "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
+ spin_lock(&journal->j_revoke_lock);
+ list_del(&record->hash);
+ spin_unlock(&journal->j_revoke_lock);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ did_revoke = 1;
+ }
+ }
+
+#ifdef JBD2_EXPENSIVE_CHECKING
+ /* There better not be one left behind by now! */
+ record = find_revoke_record(journal, bh->b_blocknr);
+ J_ASSERT_JH(jh, record == NULL);
+#endif
+
+ /* Finally, have we just cleared revoke on an unhashed
+ * buffer_head? If so, we'd better make sure we clear the
+ * revoked status on any hashed alias too, otherwise the revoke
+ * state machine will get very upset later on. */
+ if (need_cancel) {
+ struct buffer_head *bh2;
+ bh2 = __find_get_block(bh->b_bdev, bh->b_blocknr, bh->b_size);
+ if (bh2) {
+ if (bh2 != bh)
+ clear_buffer_revoked(bh2);
+ __brelse(bh2);
+ }
+ }
+ return did_revoke;
+}
+
+/*
+ * journal_clear_revoked_flag clears revoked flag of buffers in
+ * revoke table to reflect there is no revoked buffers in the next
+ * transaction which is going to be started.
+ */
+void jbd2_clear_buffer_revoked_flags(journal_t *journal)
+{
+ struct jbd2_revoke_table_s *revoke = journal->j_revoke;
+ int i = 0;
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ struct list_head *hash_list;
+ struct list_head *list_entry;
+ hash_list = &revoke->hash_table[i];
+
+ list_for_each(list_entry, hash_list) {
+ struct jbd2_revoke_record_s *record;
+ struct buffer_head *bh;
+ record = (struct jbd2_revoke_record_s *)list_entry;
+ bh = __find_get_block(journal->j_fs_dev,
+ record->blocknr,
+ journal->j_blocksize);
+ if (bh) {
+ clear_buffer_revoked(bh);
+ __brelse(bh);
+ }
+ }
+ }
+}
+
+/* journal_switch_revoke table select j_revoke for next transaction
+ * we do not want to suspend any processing until all revokes are
+ * written -bzzz
+ */
+void jbd2_journal_switch_revoke_table(journal_t *journal)
+{
+ int i;
+
+ if (journal->j_revoke == journal->j_revoke_table[0])
+ journal->j_revoke = journal->j_revoke_table[1];
+ else
+ journal->j_revoke = journal->j_revoke_table[0];
+
+ for (i = 0; i < journal->j_revoke->hash_size; i++)
+ INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
+}
+
+/*
+ * Write revoke records to the journal for all entries in the current
+ * revoke hash, deleting the entries as we go.
+ */
+void jbd2_journal_write_revoke_records(transaction_t *transaction,
+ struct list_head *log_bufs)
+{
+ journal_t *journal = transaction->t_journal;
+ struct buffer_head *descriptor;
+ struct jbd2_revoke_record_s *record;
+ struct jbd2_revoke_table_s *revoke;
+ struct list_head *hash_list;
+ int i, offset, count;
+
+ descriptor = NULL;
+ offset = 0;
+ count = 0;
+
+ /* select revoke table for committing transaction */
+ revoke = journal->j_revoke == journal->j_revoke_table[0] ?
+ journal->j_revoke_table[1] : journal->j_revoke_table[0];
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ hash_list = &revoke->hash_table[i];
+
+ while (!list_empty(hash_list)) {
+ record = (struct jbd2_revoke_record_s *)
+ hash_list->next;
+ write_one_revoke_record(transaction, log_bufs,
+ &descriptor, &offset, record);
+ count++;
+ list_del(&record->hash);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ }
+ }
+ if (descriptor)
+ flush_descriptor(journal, descriptor, offset);
+ jbd_debug(1, "Wrote %d revoke records\n", count);
+}
+
+/*
+ * Write out one revoke record. We need to create a new descriptor
+ * block if the old one is full or if we have not already created one.
+ */
+
+static void write_one_revoke_record(transaction_t *transaction,
+ struct list_head *log_bufs,
+ struct buffer_head **descriptorp,
+ int *offsetp,
+ struct jbd2_revoke_record_s *record)
+{
+ journal_t *journal = transaction->t_journal;
+ int csum_size = 0;
+ struct buffer_head *descriptor;
+ int sz, offset;
+
+ /* If we are already aborting, this all becomes a noop. We
+ still need to go round the loop in
+ jbd2_journal_write_revoke_records in order to free all of the
+ revoke records: only the IO to the journal is omitted. */
+ if (is_journal_aborted(journal))
+ return;
+
+ descriptor = *descriptorp;
+ offset = *offsetp;
+
+ /* Do we need to leave space at the end for a checksum? */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
+
+ if (jbd2_has_feature_64bit(journal))
+ sz = 8;
+ else
+ sz = 4;
+
+ /* Make sure we have a descriptor with space left for the record */
+ if (descriptor) {
+ if (offset + sz > journal->j_blocksize - csum_size) {
+ flush_descriptor(journal, descriptor, offset);
+ descriptor = NULL;
+ }
+ }
+
+ if (!descriptor) {
+ descriptor = jbd2_journal_get_descriptor_buffer(transaction,
+ JBD2_REVOKE_BLOCK);
+ if (!descriptor)
+ return;
+
+ /* Record it so that we can wait for IO completion later */
+ BUFFER_TRACE(descriptor, "file in log_bufs");
+ jbd2_file_log_bh(log_bufs, descriptor);
+
+ offset = sizeof(jbd2_journal_revoke_header_t);
+ *descriptorp = descriptor;
+ }
+
+ if (jbd2_has_feature_64bit(journal))
+ * ((__be64 *)(&descriptor->b_data[offset])) =
+ cpu_to_be64(record->blocknr);
+ else
+ * ((__be32 *)(&descriptor->b_data[offset])) =
+ cpu_to_be32(record->blocknr);
+ offset += sz;
+
+ *offsetp = offset;
+}
+
+/*
+ * Flush a revoke descriptor out to the journal. If we are aborting,
+ * this is a noop; otherwise we are generating a buffer which needs to
+ * be waited for during commit, so it has to go onto the appropriate
+ * journal buffer list.
+ */
+
+static void flush_descriptor(journal_t *journal,
+ struct buffer_head *descriptor,
+ int offset)
+{
+ jbd2_journal_revoke_header_t *header;
+
+ if (is_journal_aborted(journal)) {
+ put_bh(descriptor);
+ return;
+ }
+
+ header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
+ header->r_count = cpu_to_be32(offset);
+ jbd2_descriptor_block_csum_set(journal, descriptor);
+
+ set_buffer_jwrite(descriptor);
+ BUFFER_TRACE(descriptor, "write");
+ set_buffer_dirty(descriptor);
+ write_dirty_buffer(descriptor, REQ_SYNC);
+}
+#endif
+
+/*
+ * Revoke support for recovery.
+ *
+ * Recovery needs to be able to:
+ *
+ * record all revoke records, including the tid of the latest instance
+ * of each revoke in the journal
+ *
+ * check whether a given block in a given transaction should be replayed
+ * (ie. has not been revoked by a revoke record in that or a subsequent
+ * transaction)
+ *
+ * empty the revoke table after recovery.
+ */
+
+/*
+ * First, setting revoke records. We create a new revoke record for
+ * every block ever revoked in the log as we scan it for recovery, and
+ * we update the existing records if we find multiple revokes for a
+ * single block.
+ */
+
+int jbd2_journal_set_revoke(journal_t *journal,
+ unsigned long long blocknr,
+ tid_t sequence)
+{
+ struct jbd2_revoke_record_s *record;
+
+ record = find_revoke_record(journal, blocknr);
+ if (record) {
+ /* If we have multiple occurrences, only record the
+ * latest sequence number in the hashed record */
+ if (tid_gt(sequence, record->sequence))
+ record->sequence = sequence;
+ return 0;
+ }
+ return insert_revoke_hash(journal, blocknr, sequence);
+}
+
+/*
+ * Test revoke records. For a given block referenced in the log, has
+ * that block been revoked? A revoke record with a given transaction
+ * sequence number revokes all blocks in that transaction and earlier
+ * ones, but later transactions still need replayed.
+ */
+
+int jbd2_journal_test_revoke(journal_t *journal,
+ unsigned long long blocknr,
+ tid_t sequence)
+{
+ struct jbd2_revoke_record_s *record;
+
+ record = find_revoke_record(journal, blocknr);
+ if (!record)
+ return 0;
+ if (tid_gt(sequence, record->sequence))
+ return 0;
+ return 1;
+}
+
+/*
+ * Finally, once recovery is over, we need to clear the revoke table so
+ * that it can be reused by the running filesystem.
+ */
+
+void jbd2_journal_clear_revoke(journal_t *journal)
+{
+ int i;
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+ struct jbd2_revoke_table_s *revoke;
+
+ revoke = journal->j_revoke;
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ hash_list = &revoke->hash_table[i];
+ while (!list_empty(hash_list)) {
+ record = (struct jbd2_revoke_record_s*) hash_list->next;
+ list_del(&record->hash);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ }
+ }
+}
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
new file mode 100644
index 0000000..c0b66a7
--- /dev/null
+++ b/fs/jbd2/transaction.c
@@ -0,0 +1,2615 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/transaction.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
+ *
+ * Copyright 1998 Red Hat corp --- All Rights Reserved
+ *
+ * Generic filesystem transaction handling code; part of the ext2fs
+ * journaling system.
+ *
+ * This file manages transactions (compound commits managed by the
+ * journaling code) and handles (individual atomic operations by the
+ * filesystem).
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/hrtimer.h>
+#include <linux/backing-dev.h>
+#include <linux/bug.h>
+#include <linux/module.h>
+#include <linux/sched/mm.h>
+
+#include <trace/events/jbd2.h>
+
+static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
+static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
+
+static struct kmem_cache *transaction_cache;
+int __init jbd2_journal_init_transaction_cache(void)
+{
+ J_ASSERT(!transaction_cache);
+ transaction_cache = kmem_cache_create("jbd2_transaction_s",
+ sizeof(transaction_t),
+ 0,
+ SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
+ NULL);
+ if (transaction_cache)
+ return 0;
+ return -ENOMEM;
+}
+
+void jbd2_journal_destroy_transaction_cache(void)
+{
+ kmem_cache_destroy(transaction_cache);
+ transaction_cache = NULL;
+}
+
+void jbd2_journal_free_transaction(transaction_t *transaction)
+{
+ if (unlikely(ZERO_OR_NULL_PTR(transaction)))
+ return;
+ kmem_cache_free(transaction_cache, transaction);
+}
+
+/*
+ * jbd2_get_transaction: obtain a new transaction_t object.
+ *
+ * Simply allocate and initialise a new transaction. Create it in
+ * RUNNING state and add it to the current journal (which should not
+ * have an existing running transaction: we only make a new transaction
+ * once we have started to commit the old one).
+ *
+ * Preconditions:
+ * The journal MUST be locked. We don't perform atomic mallocs on the
+ * new transaction and we can't block without protecting against other
+ * processes trying to touch the journal while it is in transition.
+ *
+ */
+
+static transaction_t *
+jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
+{
+ transaction->t_journal = journal;
+ transaction->t_state = T_RUNNING;
+ transaction->t_start_time = ktime_get();
+ transaction->t_tid = journal->j_transaction_sequence++;
+ transaction->t_expires = jiffies + journal->j_commit_interval;
+ spin_lock_init(&transaction->t_handle_lock);
+ atomic_set(&transaction->t_updates, 0);
+ atomic_set(&transaction->t_outstanding_credits,
+ atomic_read(&journal->j_reserved_credits));
+ atomic_set(&transaction->t_handle_count, 0);
+ INIT_LIST_HEAD(&transaction->t_inode_list);
+ INIT_LIST_HEAD(&transaction->t_private_list);
+
+ /* Set up the commit timer for the new transaction. */
+ journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
+ add_timer(&journal->j_commit_timer);
+
+ J_ASSERT(journal->j_running_transaction == NULL);
+ journal->j_running_transaction = transaction;
+ transaction->t_max_wait = 0;
+ transaction->t_start = jiffies;
+ transaction->t_requested = 0;
+
+ return transaction;
+}
+
+/*
+ * Handle management.
+ *
+ * A handle_t is an object which represents a single atomic update to a
+ * filesystem, and which tracks all of the modifications which form part
+ * of that one update.
+ */
+
+/*
+ * Update transaction's maximum wait time, if debugging is enabled.
+ *
+ * In order for t_max_wait to be reliable, it must be protected by a
+ * lock. But doing so will mean that start_this_handle() can not be
+ * run in parallel on SMP systems, which limits our scalability. So
+ * unless debugging is enabled, we no longer update t_max_wait, which
+ * means that maximum wait time reported by the jbd2_run_stats
+ * tracepoint will always be zero.
+ */
+static inline void update_t_max_wait(transaction_t *transaction,
+ unsigned long ts)
+{
+#ifdef CONFIG_JBD2_DEBUG
+ if (jbd2_journal_enable_debug &&
+ time_after(transaction->t_start, ts)) {
+ ts = jbd2_time_diff(ts, transaction->t_start);
+ spin_lock(&transaction->t_handle_lock);
+ if (ts > transaction->t_max_wait)
+ transaction->t_max_wait = ts;
+ spin_unlock(&transaction->t_handle_lock);
+ }
+#endif
+}
+
+/*
+ * Wait until running transaction passes T_LOCKED state. Also starts the commit
+ * if needed. The function expects running transaction to exist and releases
+ * j_state_lock.
+ */
+static void wait_transaction_locked(journal_t *journal)
+ __releases(journal->j_state_lock)
+{
+ DEFINE_WAIT(wait);
+ int need_to_start;
+ tid_t tid = journal->j_running_transaction->t_tid;
+
+ prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
+ TASK_UNINTERRUPTIBLE);
+ need_to_start = !tid_geq(journal->j_commit_request, tid);
+ read_unlock(&journal->j_state_lock);
+ if (need_to_start)
+ jbd2_log_start_commit(journal, tid);
+ jbd2_might_wait_for_commit(journal);
+ schedule();
+ finish_wait(&journal->j_wait_transaction_locked, &wait);
+}
+
+static void sub_reserved_credits(journal_t *journal, int blocks)
+{
+ atomic_sub(blocks, &journal->j_reserved_credits);
+ wake_up(&journal->j_wait_reserved);
+}
+
+/*
+ * Wait until we can add credits for handle to the running transaction. Called
+ * with j_state_lock held for reading. Returns 0 if handle joined the running
+ * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and
+ * caller must retry.
+ */
+static int add_transaction_credits(journal_t *journal, int blocks,
+ int rsv_blocks)
+{
+ transaction_t *t = journal->j_running_transaction;
+ int needed;
+ int total = blocks + rsv_blocks;
+
+ /*
+ * If the current transaction is locked down for commit, wait
+ * for the lock to be released.
+ */
+ if (t->t_state == T_LOCKED) {
+ wait_transaction_locked(journal);
+ return 1;
+ }
+
+ /*
+ * If there is not enough space left in the log to write all
+ * potential buffers requested by this operation, we need to
+ * stall pending a log checkpoint to free some more log space.
+ */
+ needed = atomic_add_return(total, &t->t_outstanding_credits);
+ if (needed > journal->j_max_transaction_buffers) {
+ /*
+ * If the current transaction is already too large,
+ * then start to commit it: we can then go back and
+ * attach this handle to a new transaction.
+ */
+ atomic_sub(total, &t->t_outstanding_credits);
+
+ /*
+ * Is the number of reserved credits in the current transaction too
+ * big to fit this handle? Wait until reserved credits are freed.
+ */
+ if (atomic_read(&journal->j_reserved_credits) + total >
+ journal->j_max_transaction_buffers) {
+ read_unlock(&journal->j_state_lock);
+ jbd2_might_wait_for_commit(journal);
+ wait_event(journal->j_wait_reserved,
+ atomic_read(&journal->j_reserved_credits) + total <=
+ journal->j_max_transaction_buffers);
+ return 1;
+ }
+
+ wait_transaction_locked(journal);
+ return 1;
+ }
+
+ /*
+ * The commit code assumes that it can get enough log space
+ * without forcing a checkpoint. This is *critical* for
+ * correctness: a checkpoint of a buffer which is also
+ * associated with a committing transaction creates a deadlock,
+ * so commit simply cannot force through checkpoints.
+ *
+ * We must therefore ensure the necessary space in the journal
+ * *before* starting to dirty potentially checkpointed buffers
+ * in the new transaction.
+ */
+ if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) {
+ atomic_sub(total, &t->t_outstanding_credits);
+ read_unlock(&journal->j_state_lock);
+ jbd2_might_wait_for_commit(journal);
+ write_lock(&journal->j_state_lock);
+ if (jbd2_log_space_left(journal) < jbd2_space_needed(journal))
+ __jbd2_log_wait_for_space(journal);
+ write_unlock(&journal->j_state_lock);
+ return 1;
+ }
+
+ /* No reservation? We are done... */
+ if (!rsv_blocks)
+ return 0;
+
+ needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits);
+ /* We allow at most half of a transaction to be reserved */
+ if (needed > journal->j_max_transaction_buffers / 2) {
+ sub_reserved_credits(journal, rsv_blocks);
+ atomic_sub(total, &t->t_outstanding_credits);
+ read_unlock(&journal->j_state_lock);
+ jbd2_might_wait_for_commit(journal);
+ wait_event(journal->j_wait_reserved,
+ atomic_read(&journal->j_reserved_credits) + rsv_blocks
+ <= journal->j_max_transaction_buffers / 2);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * start_this_handle: Given a handle, deal with any locking or stalling
+ * needed to make sure that there is enough journal space for the handle
+ * to begin. Attach the handle to a transaction and set up the
+ * transaction's buffer credits.
+ */
+
+static int start_this_handle(journal_t *journal, handle_t *handle,
+ gfp_t gfp_mask)
+{
+ transaction_t *transaction, *new_transaction = NULL;
+ int blocks = handle->h_buffer_credits;
+ int rsv_blocks = 0;
+ unsigned long ts = jiffies;
+
+ if (handle->h_rsv_handle)
+ rsv_blocks = handle->h_rsv_handle->h_buffer_credits;
+
+ /*
+ * Limit the number of reserved credits to 1/2 of maximum transaction
+ * size and limit the number of total credits to not exceed maximum
+ * transaction size per operation.
+ */
+ if ((rsv_blocks > journal->j_max_transaction_buffers / 2) ||
+ (rsv_blocks + blocks > journal->j_max_transaction_buffers)) {
+ printk(KERN_ERR "JBD2: %s wants too many credits "
+ "credits:%d rsv_credits:%d max:%d\n",
+ current->comm, blocks, rsv_blocks,
+ journal->j_max_transaction_buffers);
+ WARN_ON(1);
+ return -ENOSPC;
+ }
+
+alloc_transaction:
+ if (!journal->j_running_transaction) {
+ /*
+ * If __GFP_FS is not present, then we may be being called from
+ * inside the fs writeback layer, so we MUST NOT fail.
+ */
+ if ((gfp_mask & __GFP_FS) == 0)
+ gfp_mask |= __GFP_NOFAIL;
+ new_transaction = kmem_cache_zalloc(transaction_cache,
+ gfp_mask);
+ if (!new_transaction)
+ return -ENOMEM;
+ }
+
+ jbd_debug(3, "New handle %p going live.\n", handle);
+
+ /*
+ * We need to hold j_state_lock until t_updates has been incremented,
+ * for proper journal barrier handling
+ */
+repeat:
+ read_lock(&journal->j_state_lock);
+ BUG_ON(journal->j_flags & JBD2_UNMOUNT);
+ if (is_journal_aborted(journal) ||
+ (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
+ read_unlock(&journal->j_state_lock);
+ jbd2_journal_free_transaction(new_transaction);
+ return -EROFS;
+ }
+
+ /*
+ * Wait on the journal's transaction barrier if necessary. Specifically
+ * we allow reserved handles to proceed because otherwise commit could
+ * deadlock on page writeback not being able to complete.
+ */
+ if (!handle->h_reserved && journal->j_barrier_count) {
+ read_unlock(&journal->j_state_lock);
+ wait_event(journal->j_wait_transaction_locked,
+ journal->j_barrier_count == 0);
+ goto repeat;
+ }
+
+ if (!journal->j_running_transaction) {
+ read_unlock(&journal->j_state_lock);
+ if (!new_transaction)
+ goto alloc_transaction;
+ write_lock(&journal->j_state_lock);
+ if (!journal->j_running_transaction &&
+ (handle->h_reserved || !journal->j_barrier_count)) {
+ jbd2_get_transaction(journal, new_transaction);
+ new_transaction = NULL;
+ }
+ write_unlock(&journal->j_state_lock);
+ goto repeat;
+ }
+
+ transaction = journal->j_running_transaction;
+
+ if (!handle->h_reserved) {
+ /* We may have dropped j_state_lock - restart in that case */
+ if (add_transaction_credits(journal, blocks, rsv_blocks))
+ goto repeat;
+ } else {
+ /*
+ * We have handle reserved so we are allowed to join T_LOCKED
+ * transaction and we don't have to check for transaction size
+ * and journal space.
+ */
+ sub_reserved_credits(journal, blocks);
+ handle->h_reserved = 0;
+ }
+
+ /* OK, account for the buffers that this operation expects to
+ * use and add the handle to the running transaction.
+ */
+ update_t_max_wait(transaction, ts);
+ handle->h_transaction = transaction;
+ handle->h_requested_credits = blocks;
+ handle->h_start_jiffies = jiffies;
+ atomic_inc(&transaction->t_updates);
+ atomic_inc(&transaction->t_handle_count);
+ jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n",
+ handle, blocks,
+ atomic_read(&transaction->t_outstanding_credits),
+ jbd2_log_space_left(journal));
+ read_unlock(&journal->j_state_lock);
+ current->journal_info = handle;
+
+ rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_);
+ jbd2_journal_free_transaction(new_transaction);
+ /*
+ * Ensure that no allocations done while the transaction is open are
+ * going to recurse back to the fs layer.
+ */
+ handle->saved_alloc_context = memalloc_nofs_save();
+ return 0;
+}
+
+/* Allocate a new handle. This should probably be in a slab... */
+static handle_t *new_handle(int nblocks)
+{
+ handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
+ if (!handle)
+ return NULL;
+ handle->h_buffer_credits = nblocks;
+ handle->h_ref = 1;
+
+ return handle;
+}
+
+handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
+ gfp_t gfp_mask, unsigned int type,
+ unsigned int line_no)
+{
+ handle_t *handle = journal_current_handle();
+ int err;
+
+ if (!journal)
+ return ERR_PTR(-EROFS);
+
+ if (handle) {
+ J_ASSERT(handle->h_transaction->t_journal == journal);
+ handle->h_ref++;
+ return handle;
+ }
+
+ handle = new_handle(nblocks);
+ if (!handle)
+ return ERR_PTR(-ENOMEM);
+ if (rsv_blocks) {
+ handle_t *rsv_handle;
+
+ rsv_handle = new_handle(rsv_blocks);
+ if (!rsv_handle) {
+ jbd2_free_handle(handle);
+ return ERR_PTR(-ENOMEM);
+ }
+ rsv_handle->h_reserved = 1;
+ rsv_handle->h_journal = journal;
+ handle->h_rsv_handle = rsv_handle;
+ }
+
+ err = start_this_handle(journal, handle, gfp_mask);
+ if (err < 0) {
+ if (handle->h_rsv_handle)
+ jbd2_free_handle(handle->h_rsv_handle);
+ jbd2_free_handle(handle);
+ return ERR_PTR(err);
+ }
+ handle->h_type = type;
+ handle->h_line_no = line_no;
+ trace_jbd2_handle_start(journal->j_fs_dev->bd_dev,
+ handle->h_transaction->t_tid, type,
+ line_no, nblocks);
+
+ return handle;
+}
+EXPORT_SYMBOL(jbd2__journal_start);
+
+
+/**
+ * handle_t *jbd2_journal_start() - Obtain a new handle.
+ * @journal: Journal to start transaction on.
+ * @nblocks: number of block buffer we might modify
+ *
+ * We make sure that the transaction can guarantee at least nblocks of
+ * modified buffers in the log. We block until the log can guarantee
+ * that much space. Additionally, if rsv_blocks > 0, we also create another
+ * handle with rsv_blocks reserved blocks in the journal. This handle is
+ * is stored in h_rsv_handle. It is not attached to any particular transaction
+ * and thus doesn't block transaction commit. If the caller uses this reserved
+ * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop()
+ * on the parent handle will dispose the reserved one. Reserved handle has to
+ * be converted to a normal handle using jbd2_journal_start_reserved() before
+ * it can be used.
+ *
+ * Return a pointer to a newly allocated handle, or an ERR_PTR() value
+ * on failure.
+ */
+handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
+{
+ return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0);
+}
+EXPORT_SYMBOL(jbd2_journal_start);
+
+void jbd2_journal_free_reserved(handle_t *handle)
+{
+ journal_t *journal = handle->h_journal;
+
+ WARN_ON(!handle->h_reserved);
+ sub_reserved_credits(journal, handle->h_buffer_credits);
+ jbd2_free_handle(handle);
+}
+EXPORT_SYMBOL(jbd2_journal_free_reserved);
+
+/**
+ * int jbd2_journal_start_reserved() - start reserved handle
+ * @handle: handle to start
+ * @type: for handle statistics
+ * @line_no: for handle statistics
+ *
+ * Start handle that has been previously reserved with jbd2_journal_reserve().
+ * This attaches @handle to the running transaction (or creates one if there's
+ * not transaction running). Unlike jbd2_journal_start() this function cannot
+ * block on journal commit, checkpointing, or similar stuff. It can block on
+ * memory allocation or frozen journal though.
+ *
+ * Return 0 on success, non-zero on error - handle is freed in that case.
+ */
+int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
+ unsigned int line_no)
+{
+ journal_t *journal = handle->h_journal;
+ int ret = -EIO;
+
+ if (WARN_ON(!handle->h_reserved)) {
+ /* Someone passed in normal handle? Just stop it. */
+ jbd2_journal_stop(handle);
+ return ret;
+ }
+ /*
+ * Usefulness of mixing of reserved and unreserved handles is
+ * questionable. So far nobody seems to need it so just error out.
+ */
+ if (WARN_ON(current->journal_info)) {
+ jbd2_journal_free_reserved(handle);
+ return ret;
+ }
+
+ handle->h_journal = NULL;
+ /*
+ * GFP_NOFS is here because callers are likely from writeback or
+ * similarly constrained call sites
+ */
+ ret = start_this_handle(journal, handle, GFP_NOFS);
+ if (ret < 0) {
+ handle->h_journal = journal;
+ jbd2_journal_free_reserved(handle);
+ return ret;
+ }
+ handle->h_type = type;
+ handle->h_line_no = line_no;
+ return 0;
+}
+EXPORT_SYMBOL(jbd2_journal_start_reserved);
+
+/**
+ * int jbd2_journal_extend() - extend buffer credits.
+ * @handle: handle to 'extend'
+ * @nblocks: nr blocks to try to extend by.
+ *
+ * Some transactions, such as large extends and truncates, can be done
+ * atomically all at once or in several stages. The operation requests
+ * a credit for a number of buffer modifications in advance, but can
+ * extend its credit if it needs more.
+ *
+ * jbd2_journal_extend tries to give the running handle more buffer credits.
+ * It does not guarantee that allocation - this is a best-effort only.
+ * The calling process MUST be able to deal cleanly with a failure to
+ * extend here.
+ *
+ * Return 0 on success, non-zero on failure.
+ *
+ * return code < 0 implies an error
+ * return code > 0 implies normal transaction-full status.
+ */
+int jbd2_journal_extend(handle_t *handle, int nblocks)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ int result;
+ int wanted;
+
+ if (is_handle_aborted(handle))
+ return -EROFS;
+ journal = transaction->t_journal;
+
+ result = 1;
+
+ read_lock(&journal->j_state_lock);
+
+ /* Don't extend a locked-down transaction! */
+ if (transaction->t_state != T_RUNNING) {
+ jbd_debug(3, "denied handle %p %d blocks: "
+ "transaction not running\n", handle, nblocks);
+ goto error_out;
+ }
+
+ spin_lock(&transaction->t_handle_lock);
+ wanted = atomic_add_return(nblocks,
+ &transaction->t_outstanding_credits);
+
+ if (wanted > journal->j_max_transaction_buffers) {
+ jbd_debug(3, "denied handle %p %d blocks: "
+ "transaction too large\n", handle, nblocks);
+ atomic_sub(nblocks, &transaction->t_outstanding_credits);
+ goto unlock;
+ }
+
+ if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) >
+ jbd2_log_space_left(journal)) {
+ jbd_debug(3, "denied handle %p %d blocks: "
+ "insufficient log space\n", handle, nblocks);
+ atomic_sub(nblocks, &transaction->t_outstanding_credits);
+ goto unlock;
+ }
+
+ trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
+ transaction->t_tid,
+ handle->h_type, handle->h_line_no,
+ handle->h_buffer_credits,
+ nblocks);
+
+ handle->h_buffer_credits += nblocks;
+ handle->h_requested_credits += nblocks;
+ result = 0;
+
+ jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
+unlock:
+ spin_unlock(&transaction->t_handle_lock);
+error_out:
+ read_unlock(&journal->j_state_lock);
+ return result;
+}
+
+
+/**
+ * int jbd2_journal_restart() - restart a handle .
+ * @handle: handle to restart
+ * @nblocks: nr credits requested
+ * @gfp_mask: memory allocation flags (for start_this_handle)
+ *
+ * Restart a handle for a multi-transaction filesystem
+ * operation.
+ *
+ * If the jbd2_journal_extend() call above fails to grant new buffer credits
+ * to a running handle, a call to jbd2_journal_restart will commit the
+ * handle's transaction so far and reattach the handle to a new
+ * transaction capable of guaranteeing the requested number of
+ * credits. We preserve reserved handle if there's any attached to the
+ * passed in handle.
+ */
+int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ tid_t tid;
+ int need_to_start, ret;
+
+ /* If we've had an abort of any type, don't even think about
+ * actually doing the restart! */
+ if (is_handle_aborted(handle))
+ return 0;
+ journal = transaction->t_journal;
+
+ /*
+ * First unlink the handle from its current transaction, and start the
+ * commit on that.
+ */
+ J_ASSERT(atomic_read(&transaction->t_updates) > 0);
+ J_ASSERT(journal_current_handle() == handle);
+
+ read_lock(&journal->j_state_lock);
+ spin_lock(&transaction->t_handle_lock);
+ atomic_sub(handle->h_buffer_credits,
+ &transaction->t_outstanding_credits);
+ if (handle->h_rsv_handle) {
+ sub_reserved_credits(journal,
+ handle->h_rsv_handle->h_buffer_credits);
+ }
+ if (atomic_dec_and_test(&transaction->t_updates))
+ wake_up(&journal->j_wait_updates);
+ tid = transaction->t_tid;
+ spin_unlock(&transaction->t_handle_lock);
+ handle->h_transaction = NULL;
+ current->journal_info = NULL;
+
+ jbd_debug(2, "restarting handle %p\n", handle);
+ need_to_start = !tid_geq(journal->j_commit_request, tid);
+ read_unlock(&journal->j_state_lock);
+ if (need_to_start)
+ jbd2_log_start_commit(journal, tid);
+
+ rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
+ handle->h_buffer_credits = nblocks;
+ /*
+ * Restore the original nofs context because the journal restart
+ * is basically the same thing as journal stop and start.
+ * start_this_handle will start a new nofs context.
+ */
+ memalloc_nofs_restore(handle->saved_alloc_context);
+ ret = start_this_handle(journal, handle, gfp_mask);
+ return ret;
+}
+EXPORT_SYMBOL(jbd2__journal_restart);
+
+
+int jbd2_journal_restart(handle_t *handle, int nblocks)
+{
+ return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
+}
+EXPORT_SYMBOL(jbd2_journal_restart);
+
+/**
+ * void jbd2_journal_lock_updates () - establish a transaction barrier.
+ * @journal: Journal to establish a barrier on.
+ *
+ * This locks out any further updates from being started, and blocks
+ * until all existing updates have completed, returning only once the
+ * journal is in a quiescent state with no updates running.
+ *
+ * The journal lock should not be held on entry.
+ */
+void jbd2_journal_lock_updates(journal_t *journal)
+{
+ DEFINE_WAIT(wait);
+
+ jbd2_might_wait_for_commit(journal);
+
+ write_lock(&journal->j_state_lock);
+ ++journal->j_barrier_count;
+
+ /* Wait until there are no reserved handles */
+ if (atomic_read(&journal->j_reserved_credits)) {
+ write_unlock(&journal->j_state_lock);
+ wait_event(journal->j_wait_reserved,
+ atomic_read(&journal->j_reserved_credits) == 0);
+ write_lock(&journal->j_state_lock);
+ }
+
+ /* Wait until there are no running updates */
+ while (1) {
+ transaction_t *transaction = journal->j_running_transaction;
+
+ if (!transaction)
+ break;
+
+ spin_lock(&transaction->t_handle_lock);
+ prepare_to_wait(&journal->j_wait_updates, &wait,
+ TASK_UNINTERRUPTIBLE);
+ if (!atomic_read(&transaction->t_updates)) {
+ spin_unlock(&transaction->t_handle_lock);
+ finish_wait(&journal->j_wait_updates, &wait);
+ break;
+ }
+ spin_unlock(&transaction->t_handle_lock);
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ finish_wait(&journal->j_wait_updates, &wait);
+ write_lock(&journal->j_state_lock);
+ }
+ write_unlock(&journal->j_state_lock);
+
+ /*
+ * We have now established a barrier against other normal updates, but
+ * we also need to barrier against other jbd2_journal_lock_updates() calls
+ * to make sure that we serialise special journal-locked operations
+ * too.
+ */
+ mutex_lock(&journal->j_barrier);
+}
+
+/**
+ * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier
+ * @journal: Journal to release the barrier on.
+ *
+ * Release a transaction barrier obtained with jbd2_journal_lock_updates().
+ *
+ * Should be called without the journal lock held.
+ */
+void jbd2_journal_unlock_updates (journal_t *journal)
+{
+ J_ASSERT(journal->j_barrier_count != 0);
+
+ mutex_unlock(&journal->j_barrier);
+ write_lock(&journal->j_state_lock);
+ --journal->j_barrier_count;
+ write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_transaction_locked);
+}
+
+static void warn_dirty_buffer(struct buffer_head *bh)
+{
+ printk(KERN_WARNING
+ "JBD2: Spotted dirty metadata buffer (dev = %pg, blocknr = %llu). "
+ "There's a risk of filesystem corruption in case of system "
+ "crash.\n",
+ bh->b_bdev, (unsigned long long)bh->b_blocknr);
+}
+
+/* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */
+static void jbd2_freeze_jh_data(struct journal_head *jh)
+{
+ struct page *page;
+ int offset;
+ char *source;
+ struct buffer_head *bh = jh2bh(jh);
+
+ J_EXPECT_JH(jh, buffer_uptodate(bh), "Possible IO failure.\n");
+ page = bh->b_page;
+ offset = offset_in_page(bh->b_data);
+ source = kmap_atomic(page);
+ /* Fire data frozen trigger just before we copy the data */
+ jbd2_buffer_frozen_trigger(jh, source + offset, jh->b_triggers);
+ memcpy(jh->b_frozen_data, source + offset, bh->b_size);
+ kunmap_atomic(source);
+
+ /*
+ * Now that the frozen data is saved off, we need to store any matching
+ * triggers.
+ */
+ jh->b_frozen_triggers = jh->b_triggers;
+}
+
+/*
+ * If the buffer is already part of the current transaction, then there
+ * is nothing we need to do. If it is already part of a prior
+ * transaction which we are still committing to disk, then we need to
+ * make sure that we do not overwrite the old copy: we do copy-out to
+ * preserve the copy going to disk. We also account the buffer against
+ * the handle's metadata buffer credits (unless the buffer is already
+ * part of the transaction, that is).
+ *
+ */
+static int
+do_get_write_access(handle_t *handle, struct journal_head *jh,
+ int force_copy)
+{
+ struct buffer_head *bh;
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ int error;
+ char *frozen_buffer = NULL;
+ unsigned long start_lock, time_lock;
+
+ if (is_handle_aborted(handle))
+ return -EROFS;
+ journal = transaction->t_journal;
+
+ jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
+
+ JBUFFER_TRACE(jh, "entry");
+repeat:
+ bh = jh2bh(jh);
+
+ /* @@@ Need to check for errors here at some point. */
+
+ start_lock = jiffies;
+ lock_buffer(bh);
+ jbd_lock_bh_state(bh);
+
+ /* If it takes too long to lock the buffer, trace it */
+ time_lock = jbd2_time_diff(start_lock, jiffies);
+ if (time_lock > HZ/10)
+ trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev,
+ jiffies_to_msecs(time_lock));
+
+ /* We now hold the buffer lock so it is safe to query the buffer
+ * state. Is the buffer dirty?
+ *
+ * If so, there are two possibilities. The buffer may be
+ * non-journaled, and undergoing a quite legitimate writeback.
+ * Otherwise, it is journaled, and we don't expect dirty buffers
+ * in that state (the buffers should be marked JBD_Dirty
+ * instead.) So either the IO is being done under our own
+ * control and this is a bug, or it's a third party IO such as
+ * dump(8) (which may leave the buffer scheduled for read ---
+ * ie. locked but not dirty) or tune2fs (which may actually have
+ * the buffer dirtied, ugh.) */
+
+ if (buffer_dirty(bh)) {
+ /*
+ * First question: is this buffer already part of the current
+ * transaction or the existing committing transaction?
+ */
+ if (jh->b_transaction) {
+ J_ASSERT_JH(jh,
+ jh->b_transaction == transaction ||
+ jh->b_transaction ==
+ journal->j_committing_transaction);
+ if (jh->b_next_transaction)
+ J_ASSERT_JH(jh, jh->b_next_transaction ==
+ transaction);
+ warn_dirty_buffer(bh);
+ }
+ /*
+ * In any case we need to clean the dirty flag and we must
+ * do it under the buffer lock to be sure we don't race
+ * with running write-out.
+ */
+ JBUFFER_TRACE(jh, "Journalling dirty buffer");
+ clear_buffer_dirty(bh);
+ set_buffer_jbddirty(bh);
+ }
+
+ unlock_buffer(bh);
+
+ error = -EROFS;
+ if (is_handle_aborted(handle)) {
+ jbd_unlock_bh_state(bh);
+ goto out;
+ }
+ error = 0;
+
+ /*
+ * The buffer is already part of this transaction if b_transaction or
+ * b_next_transaction points to it
+ */
+ if (jh->b_transaction == transaction ||
+ jh->b_next_transaction == transaction)
+ goto done;
+
+ /*
+ * this is the first time this transaction is touching this buffer,
+ * reset the modified flag
+ */
+ jh->b_modified = 0;
+
+ /*
+ * If the buffer is not journaled right now, we need to make sure it
+ * doesn't get written to disk before the caller actually commits the
+ * new data
+ */
+ if (!jh->b_transaction) {
+ JBUFFER_TRACE(jh, "no transaction");
+ J_ASSERT_JH(jh, !jh->b_next_transaction);
+ JBUFFER_TRACE(jh, "file as BJ_Reserved");
+ /*
+ * Make sure all stores to jh (b_modified, b_frozen_data) are
+ * visible before attaching it to the running transaction.
+ * Paired with barrier in jbd2_write_access_granted()
+ */
+ smp_wmb();
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
+ spin_unlock(&journal->j_list_lock);
+ goto done;
+ }
+ /*
+ * If there is already a copy-out version of this buffer, then we don't
+ * need to make another one
+ */
+ if (jh->b_frozen_data) {
+ JBUFFER_TRACE(jh, "has frozen data");
+ J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+ goto attach_next;
+ }
+
+ JBUFFER_TRACE(jh, "owned by older transaction");
+ J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+ J_ASSERT_JH(jh, jh->b_transaction == journal->j_committing_transaction);
+
+ /*
+ * There is one case we have to be very careful about. If the
+ * committing transaction is currently writing this buffer out to disk
+ * and has NOT made a copy-out, then we cannot modify the buffer
+ * contents at all right now. The essence of copy-out is that it is
+ * the extra copy, not the primary copy, which gets journaled. If the
+ * primary copy is already going to disk then we cannot do copy-out
+ * here.
+ */
+ if (buffer_shadow(bh)) {
+ JBUFFER_TRACE(jh, "on shadow: sleep");
+ jbd_unlock_bh_state(bh);
+ wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE);
+ goto repeat;
+ }
+
+ /*
+ * Only do the copy if the currently-owning transaction still needs it.
+ * If buffer isn't on BJ_Metadata list, the committing transaction is
+ * past that stage (here we use the fact that BH_Shadow is set under
+ * bh_state lock together with refiling to BJ_Shadow list and at this
+ * point we know the buffer doesn't have BH_Shadow set).
+ *
+ * Subtle point, though: if this is a get_undo_access, then we will be
+ * relying on the frozen_data to contain the new value of the
+ * committed_data record after the transaction, so we HAVE to force the
+ * frozen_data copy in that case.
+ */
+ if (jh->b_jlist == BJ_Metadata || force_copy) {
+ JBUFFER_TRACE(jh, "generate frozen data");
+ if (!frozen_buffer) {
+ JBUFFER_TRACE(jh, "allocate memory for buffer");
+ jbd_unlock_bh_state(bh);
+ frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size,
+ GFP_NOFS | __GFP_NOFAIL);
+ goto repeat;
+ }
+ jh->b_frozen_data = frozen_buffer;
+ frozen_buffer = NULL;
+ jbd2_freeze_jh_data(jh);
+ }
+attach_next:
+ /*
+ * Make sure all stores to jh (b_modified, b_frozen_data) are visible
+ * before attaching it to the running transaction. Paired with barrier
+ * in jbd2_write_access_granted()
+ */
+ smp_wmb();
+ jh->b_next_transaction = transaction;
+
+done:
+ jbd_unlock_bh_state(bh);
+
+ /*
+ * If we are about to journal a buffer, then any revoke pending on it is
+ * no longer valid
+ */
+ jbd2_journal_cancel_revoke(handle, jh);
+
+out:
+ if (unlikely(frozen_buffer)) /* It's usually NULL */
+ jbd2_free(frozen_buffer, bh->b_size);
+
+ JBUFFER_TRACE(jh, "exit");
+ return error;
+}
+
+/* Fast check whether buffer is already attached to the required transaction */
+static bool jbd2_write_access_granted(handle_t *handle, struct buffer_head *bh,
+ bool undo)
+{
+ struct journal_head *jh;
+ bool ret = false;
+
+ /* Dirty buffers require special handling... */
+ if (buffer_dirty(bh))
+ return false;
+
+ /*
+ * RCU protects us from dereferencing freed pages. So the checks we do
+ * are guaranteed not to oops. However the jh slab object can get freed
+ * & reallocated while we work with it. So we have to be careful. When
+ * we see jh attached to the running transaction, we know it must stay
+ * so until the transaction is committed. Thus jh won't be freed and
+ * will be attached to the same bh while we run. However it can
+ * happen jh gets freed, reallocated, and attached to the transaction
+ * just after we get pointer to it from bh. So we have to be careful
+ * and recheck jh still belongs to our bh before we return success.
+ */
+ rcu_read_lock();
+ if (!buffer_jbd(bh))
+ goto out;
+ /* This should be bh2jh() but that doesn't work with inline functions */
+ jh = READ_ONCE(bh->b_private);
+ if (!jh)
+ goto out;
+ /* For undo access buffer must have data copied */
+ if (undo && !jh->b_committed_data)
+ goto out;
+ if (jh->b_transaction != handle->h_transaction &&
+ jh->b_next_transaction != handle->h_transaction)
+ goto out;
+ /*
+ * There are two reasons for the barrier here:
+ * 1) Make sure to fetch b_bh after we did previous checks so that we
+ * detect when jh went through free, realloc, attach to transaction
+ * while we were checking. Paired with implicit barrier in that path.
+ * 2) So that access to bh done after jbd2_write_access_granted()
+ * doesn't get reordered and see inconsistent state of concurrent
+ * do_get_write_access().
+ */
+ smp_mb();
+ if (unlikely(jh->b_bh != bh))
+ goto out;
+ ret = true;
+out:
+ rcu_read_unlock();
+ return ret;
+}
+
+/**
+ * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
+ * @handle: transaction to add buffer modifications to
+ * @bh: bh to be used for metadata writes
+ *
+ * Returns: error code or 0 on success.
+ *
+ * In full data journalling mode the buffer may be of type BJ_AsyncData,
+ * because we're ``write()ing`` a buffer which is also part of a shared mapping.
+ */
+
+int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
+{
+ struct journal_head *jh;
+ int rc;
+
+ if (jbd2_write_access_granted(handle, bh, false))
+ return 0;
+
+ jh = jbd2_journal_add_journal_head(bh);
+ /* We do not want to get caught playing with fields which the
+ * log thread also manipulates. Make sure that the buffer
+ * completes any outstanding IO before proceeding. */
+ rc = do_get_write_access(handle, jh, 0);
+ jbd2_journal_put_journal_head(jh);
+ return rc;
+}
+
+
+/*
+ * When the user wants to journal a newly created buffer_head
+ * (ie. getblk() returned a new buffer and we are going to populate it
+ * manually rather than reading off disk), then we need to keep the
+ * buffer_head locked until it has been completely filled with new
+ * data. In this case, we should be able to make the assertion that
+ * the bh is not already part of an existing transaction.
+ *
+ * The buffer should already be locked by the caller by this point.
+ * There is no lock ranking violation: it was a newly created,
+ * unlocked buffer beforehand. */
+
+/**
+ * int jbd2_journal_get_create_access () - notify intent to use newly created bh
+ * @handle: transaction to new buffer to
+ * @bh: new buffer.
+ *
+ * Call this if you create a new bh.
+ */
+int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ struct journal_head *jh = jbd2_journal_add_journal_head(bh);
+ int err;
+
+ jbd_debug(5, "journal_head %p\n", jh);
+ err = -EROFS;
+ if (is_handle_aborted(handle))
+ goto out;
+ journal = transaction->t_journal;
+ err = 0;
+
+ JBUFFER_TRACE(jh, "entry");
+ /*
+ * The buffer may already belong to this transaction due to pre-zeroing
+ * in the filesystem's new_block code. It may also be on the previous,
+ * committing transaction's lists, but it HAS to be in Forget state in
+ * that case: the transaction must have deleted the buffer for it to be
+ * reused here.
+ */
+ jbd_lock_bh_state(bh);
+ J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
+ jh->b_transaction == NULL ||
+ (jh->b_transaction == journal->j_committing_transaction &&
+ jh->b_jlist == BJ_Forget)));
+
+ J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+ J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
+
+ if (jh->b_transaction == NULL) {
+ /*
+ * Previous jbd2_journal_forget() could have left the buffer
+ * with jbddirty bit set because it was being committed. When
+ * the commit finished, we've filed the buffer for
+ * checkpointing and marked it dirty. Now we are reallocating
+ * the buffer so the transaction freeing it must have
+ * committed and so it's safe to clear the dirty bit.
+ */
+ clear_buffer_dirty(jh2bh(jh));
+ /* first access by this transaction */
+ jh->b_modified = 0;
+
+ JBUFFER_TRACE(jh, "file as BJ_Reserved");
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
+ spin_unlock(&journal->j_list_lock);
+ } else if (jh->b_transaction == journal->j_committing_transaction) {
+ /* first access by this transaction */
+ jh->b_modified = 0;
+
+ JBUFFER_TRACE(jh, "set next transaction");
+ spin_lock(&journal->j_list_lock);
+ jh->b_next_transaction = transaction;
+ spin_unlock(&journal->j_list_lock);
+ }
+ jbd_unlock_bh_state(bh);
+
+ /*
+ * akpm: I added this. ext3_alloc_branch can pick up new indirect
+ * blocks which contain freed but then revoked metadata. We need
+ * to cancel the revoke in case we end up freeing it yet again
+ * and the reallocating as data - this would cause a second revoke,
+ * which hits an assertion error.
+ */
+ JBUFFER_TRACE(jh, "cancelling revoke");
+ jbd2_journal_cancel_revoke(handle, jh);
+out:
+ jbd2_journal_put_journal_head(jh);
+ return err;
+}
+
+/**
+ * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with
+ * non-rewindable consequences
+ * @handle: transaction
+ * @bh: buffer to undo
+ *
+ * Sometimes there is a need to distinguish between metadata which has
+ * been committed to disk and that which has not. The ext3fs code uses
+ * this for freeing and allocating space, we have to make sure that we
+ * do not reuse freed space until the deallocation has been committed,
+ * since if we overwrote that space we would make the delete
+ * un-rewindable in case of a crash.
+ *
+ * To deal with that, jbd2_journal_get_undo_access requests write access to a
+ * buffer for parts of non-rewindable operations such as delete
+ * operations on the bitmaps. The journaling code must keep a copy of
+ * the buffer's contents prior to the undo_access call until such time
+ * as we know that the buffer has definitely been committed to disk.
+ *
+ * We never need to know which transaction the committed data is part
+ * of, buffers touched here are guaranteed to be dirtied later and so
+ * will be committed to a new transaction in due course, at which point
+ * we can discard the old committed data pointer.
+ *
+ * Returns error number or 0 on success.
+ */
+int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
+{
+ int err;
+ struct journal_head *jh;
+ char *committed_data = NULL;
+
+ JBUFFER_TRACE(jh, "entry");
+ if (jbd2_write_access_granted(handle, bh, true))
+ return 0;
+
+ jh = jbd2_journal_add_journal_head(bh);
+ /*
+ * Do this first --- it can drop the journal lock, so we want to
+ * make sure that obtaining the committed_data is done
+ * atomically wrt. completion of any outstanding commits.
+ */
+ err = do_get_write_access(handle, jh, 1);
+ if (err)
+ goto out;
+
+repeat:
+ if (!jh->b_committed_data)
+ committed_data = jbd2_alloc(jh2bh(jh)->b_size,
+ GFP_NOFS|__GFP_NOFAIL);
+
+ jbd_lock_bh_state(bh);
+ if (!jh->b_committed_data) {
+ /* Copy out the current buffer contents into the
+ * preserved, committed copy. */
+ JBUFFER_TRACE(jh, "generate b_committed data");
+ if (!committed_data) {
+ jbd_unlock_bh_state(bh);
+ goto repeat;
+ }
+
+ jh->b_committed_data = committed_data;
+ committed_data = NULL;
+ memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
+ }
+ jbd_unlock_bh_state(bh);
+out:
+ jbd2_journal_put_journal_head(jh);
+ if (unlikely(committed_data))
+ jbd2_free(committed_data, bh->b_size);
+ return err;
+}
+
+/**
+ * void jbd2_journal_set_triggers() - Add triggers for commit writeout
+ * @bh: buffer to trigger on
+ * @type: struct jbd2_buffer_trigger_type containing the trigger(s).
+ *
+ * Set any triggers on this journal_head. This is always safe, because
+ * triggers for a committing buffer will be saved off, and triggers for
+ * a running transaction will match the buffer in that transaction.
+ *
+ * Call with NULL to clear the triggers.
+ */
+void jbd2_journal_set_triggers(struct buffer_head *bh,
+ struct jbd2_buffer_trigger_type *type)
+{
+ struct journal_head *jh = jbd2_journal_grab_journal_head(bh);
+
+ if (WARN_ON(!jh))
+ return;
+ jh->b_triggers = type;
+ jbd2_journal_put_journal_head(jh);
+}
+
+void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
+ struct jbd2_buffer_trigger_type *triggers)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ if (!triggers || !triggers->t_frozen)
+ return;
+
+ triggers->t_frozen(triggers, bh, mapped_data, bh->b_size);
+}
+
+void jbd2_buffer_abort_trigger(struct journal_head *jh,
+ struct jbd2_buffer_trigger_type *triggers)
+{
+ if (!triggers || !triggers->t_abort)
+ return;
+
+ triggers->t_abort(triggers, jh2bh(jh));
+}
+
+/**
+ * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata
+ * @handle: transaction to add buffer to.
+ * @bh: buffer to mark
+ *
+ * mark dirty metadata which needs to be journaled as part of the current
+ * transaction.
+ *
+ * The buffer must have previously had jbd2_journal_get_write_access()
+ * called so that it has a valid journal_head attached to the buffer
+ * head.
+ *
+ * The buffer is placed on the transaction's metadata list and is marked
+ * as belonging to the transaction.
+ *
+ * Returns error number or 0 on success.
+ *
+ * Special care needs to be taken if the buffer already belongs to the
+ * current committing transaction (in which case we should have frozen
+ * data present for that commit). In that case, we don't relink the
+ * buffer: that only gets done when the old transaction finally
+ * completes its commit.
+ */
+int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ struct journal_head *jh;
+ int ret = 0;
+
+ if (is_handle_aborted(handle))
+ return -EROFS;
+ if (!buffer_jbd(bh)) {
+ ret = -EUCLEAN;
+ goto out;
+ }
+ /*
+ * We don't grab jh reference here since the buffer must be part
+ * of the running transaction.
+ */
+ jh = bh2jh(bh);
+ /*
+ * This and the following assertions are unreliable since we may see jh
+ * in inconsistent state unless we grab bh_state lock. But this is
+ * crucial to catch bugs so let's do a reliable check until the
+ * lockless handling is fully proven.
+ */
+ if (jh->b_transaction != transaction &&
+ jh->b_next_transaction != transaction) {
+ jbd_lock_bh_state(bh);
+ J_ASSERT_JH(jh, jh->b_transaction == transaction ||
+ jh->b_next_transaction == transaction);
+ jbd_unlock_bh_state(bh);
+ }
+ if (jh->b_modified == 1) {
+ /* If it's in our transaction it must be in BJ_Metadata list. */
+ if (jh->b_transaction == transaction &&
+ jh->b_jlist != BJ_Metadata) {
+ jbd_lock_bh_state(bh);
+ if (jh->b_transaction == transaction &&
+ jh->b_jlist != BJ_Metadata)
+ pr_err("JBD2: assertion failure: h_type=%u "
+ "h_line_no=%u block_no=%llu jlist=%u\n",
+ handle->h_type, handle->h_line_no,
+ (unsigned long long) bh->b_blocknr,
+ jh->b_jlist);
+ J_ASSERT_JH(jh, jh->b_transaction != transaction ||
+ jh->b_jlist == BJ_Metadata);
+ jbd_unlock_bh_state(bh);
+ }
+ goto out;
+ }
+
+ journal = transaction->t_journal;
+ jbd_debug(5, "journal_head %p\n", jh);
+ JBUFFER_TRACE(jh, "entry");
+
+ jbd_lock_bh_state(bh);
+
+ if (jh->b_modified == 0) {
+ /*
+ * This buffer's got modified and becoming part
+ * of the transaction. This needs to be done
+ * once a transaction -bzzz
+ */
+ if (handle->h_buffer_credits <= 0) {
+ ret = -ENOSPC;
+ goto out_unlock_bh;
+ }
+ jh->b_modified = 1;
+ handle->h_buffer_credits--;
+ }
+
+ /*
+ * fastpath, to avoid expensive locking. If this buffer is already
+ * on the running transaction's metadata list there is nothing to do.
+ * Nobody can take it off again because there is a handle open.
+ * I _think_ we're OK here with SMP barriers - a mistaken decision will
+ * result in this test being false, so we go in and take the locks.
+ */
+ if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
+ JBUFFER_TRACE(jh, "fastpath");
+ if (unlikely(jh->b_transaction !=
+ journal->j_running_transaction)) {
+ printk(KERN_ERR "JBD2: %s: "
+ "jh->b_transaction (%llu, %p, %u) != "
+ "journal->j_running_transaction (%p, %u)\n",
+ journal->j_devname,
+ (unsigned long long) bh->b_blocknr,
+ jh->b_transaction,
+ jh->b_transaction ? jh->b_transaction->t_tid : 0,
+ journal->j_running_transaction,
+ journal->j_running_transaction ?
+ journal->j_running_transaction->t_tid : 0);
+ ret = -EINVAL;
+ }
+ goto out_unlock_bh;
+ }
+
+ set_buffer_jbddirty(bh);
+
+ /*
+ * Metadata already on the current transaction list doesn't
+ * need to be filed. Metadata on another transaction's list must
+ * be committing, and will be refiled once the commit completes:
+ * leave it alone for now.
+ */
+ if (jh->b_transaction != transaction) {
+ JBUFFER_TRACE(jh, "already on other transaction");
+ if (unlikely(((jh->b_transaction !=
+ journal->j_committing_transaction)) ||
+ (jh->b_next_transaction != transaction))) {
+ printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: "
+ "bad jh for block %llu: "
+ "transaction (%p, %u), "
+ "jh->b_transaction (%p, %u), "
+ "jh->b_next_transaction (%p, %u), jlist %u\n",
+ journal->j_devname,
+ (unsigned long long) bh->b_blocknr,
+ transaction, transaction->t_tid,
+ jh->b_transaction,
+ jh->b_transaction ?
+ jh->b_transaction->t_tid : 0,
+ jh->b_next_transaction,
+ jh->b_next_transaction ?
+ jh->b_next_transaction->t_tid : 0,
+ jh->b_jlist);
+ WARN_ON(1);
+ ret = -EINVAL;
+ }
+ /* And this case is illegal: we can't reuse another
+ * transaction's data buffer, ever. */
+ goto out_unlock_bh;
+ }
+
+ /* That test should have eliminated the following case: */
+ J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
+
+ JBUFFER_TRACE(jh, "file as BJ_Metadata");
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
+ spin_unlock(&journal->j_list_lock);
+out_unlock_bh:
+ jbd_unlock_bh_state(bh);
+out:
+ JBUFFER_TRACE(jh, "exit");
+ return ret;
+}
+
+/**
+ * void jbd2_journal_forget() - bforget() for potentially-journaled buffers.
+ * @handle: transaction handle
+ * @bh: bh to 'forget'
+ *
+ * We can only do the bforget if there are no commits pending against the
+ * buffer. If the buffer is dirty in the current running transaction we
+ * can safely unlink it.
+ *
+ * bh may not be a journalled buffer at all - it may be a non-JBD
+ * buffer which came off the hashtable. Check for this.
+ *
+ * Decrements bh->b_count by one.
+ *
+ * Allow this call even if the handle has aborted --- it may be part of
+ * the caller's cleanup after an abort.
+ */
+int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ struct journal_head *jh;
+ int drop_reserve = 0;
+ int err = 0;
+ int was_modified = 0;
+
+ if (is_handle_aborted(handle))
+ return -EROFS;
+ journal = transaction->t_journal;
+
+ BUFFER_TRACE(bh, "entry");
+
+ jbd_lock_bh_state(bh);
+
+ if (!buffer_jbd(bh))
+ goto not_jbd;
+ jh = bh2jh(bh);
+
+ /* Critical error: attempting to delete a bitmap buffer, maybe?
+ * Don't do any jbd operations, and return an error. */
+ if (!J_EXPECT_JH(jh, !jh->b_committed_data,
+ "inconsistent data on disk")) {
+ err = -EIO;
+ goto not_jbd;
+ }
+
+ /* keep track of whether or not this transaction modified us */
+ was_modified = jh->b_modified;
+
+ /*
+ * The buffer's going from the transaction, we must drop
+ * all references -bzzz
+ */
+ jh->b_modified = 0;
+
+ if (jh->b_transaction == transaction) {
+ J_ASSERT_JH(jh, !jh->b_frozen_data);
+
+ /* If we are forgetting a buffer which is already part
+ * of this transaction, then we can just drop it from
+ * the transaction immediately. */
+ clear_buffer_dirty(bh);
+ clear_buffer_jbddirty(bh);
+
+ JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
+
+ /*
+ * we only want to drop a reference if this transaction
+ * modified the buffer
+ */
+ if (was_modified)
+ drop_reserve = 1;
+
+ /*
+ * We are no longer going to journal this buffer.
+ * However, the commit of this transaction is still
+ * important to the buffer: the delete that we are now
+ * processing might obsolete an old log entry, so by
+ * committing, we can satisfy the buffer's checkpoint.
+ *
+ * So, if we have a checkpoint on the buffer, we should
+ * now refile the buffer on our BJ_Forget list so that
+ * we know to remove the checkpoint after we commit.
+ */
+
+ spin_lock(&journal->j_list_lock);
+ if (jh->b_cp_transaction) {
+ __jbd2_journal_temp_unlink_buffer(jh);
+ __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
+ } else {
+ __jbd2_journal_unfile_buffer(jh);
+ if (!buffer_jbd(bh)) {
+ spin_unlock(&journal->j_list_lock);
+ jbd_unlock_bh_state(bh);
+ __bforget(bh);
+ goto drop;
+ }
+ }
+ spin_unlock(&journal->j_list_lock);
+ } else if (jh->b_transaction) {
+ J_ASSERT_JH(jh, (jh->b_transaction ==
+ journal->j_committing_transaction));
+ /* However, if the buffer is still owned by a prior
+ * (committing) transaction, we can't drop it yet... */
+ JBUFFER_TRACE(jh, "belongs to older transaction");
+ /* ... but we CAN drop it from the new transaction if we
+ * have also modified it since the original commit. */
+
+ if (jh->b_next_transaction) {
+ J_ASSERT(jh->b_next_transaction == transaction);
+ spin_lock(&journal->j_list_lock);
+ jh->b_next_transaction = NULL;
+ spin_unlock(&journal->j_list_lock);
+
+ /*
+ * only drop a reference if this transaction modified
+ * the buffer
+ */
+ if (was_modified)
+ drop_reserve = 1;
+ }
+ }
+
+not_jbd:
+ jbd_unlock_bh_state(bh);
+ __brelse(bh);
+drop:
+ if (drop_reserve) {
+ /* no need to reserve log space for this block -bzzz */
+ handle->h_buffer_credits++;
+ }
+ return err;
+}
+
+/**
+ * int jbd2_journal_stop() - complete a transaction
+ * @handle: transaction to complete.
+ *
+ * All done for a particular handle.
+ *
+ * There is not much action needed here. We just return any remaining
+ * buffer credits to the transaction and remove the handle. The only
+ * complication is that we need to start a commit operation if the
+ * filesystem is marked for synchronous update.
+ *
+ * jbd2_journal_stop itself will not usually return an error, but it may
+ * do so in unusual circumstances. In particular, expect it to
+ * return -EIO if a jbd2_journal_abort has been executed since the
+ * transaction began.
+ */
+int jbd2_journal_stop(handle_t *handle)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+ int err = 0, wait_for_commit = 0;
+ tid_t tid;
+ pid_t pid;
+
+ if (!transaction) {
+ /*
+ * Handle is already detached from the transaction so
+ * there is nothing to do other than decrease a refcount,
+ * or free the handle if refcount drops to zero
+ */
+ if (--handle->h_ref > 0) {
+ jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
+ handle->h_ref);
+ return err;
+ } else {
+ if (handle->h_rsv_handle)
+ jbd2_free_handle(handle->h_rsv_handle);
+ goto free_and_exit;
+ }
+ }
+ journal = transaction->t_journal;
+
+ J_ASSERT(journal_current_handle() == handle);
+
+ if (is_handle_aborted(handle))
+ err = -EIO;
+ else
+ J_ASSERT(atomic_read(&transaction->t_updates) > 0);
+
+ if (--handle->h_ref > 0) {
+ jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
+ handle->h_ref);
+ return err;
+ }
+
+ jbd_debug(4, "Handle %p going down\n", handle);
+ trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
+ transaction->t_tid,
+ handle->h_type, handle->h_line_no,
+ jiffies - handle->h_start_jiffies,
+ handle->h_sync, handle->h_requested_credits,
+ (handle->h_requested_credits -
+ handle->h_buffer_credits));
+
+ /*
+ * Implement synchronous transaction batching. If the handle
+ * was synchronous, don't force a commit immediately. Let's
+ * yield and let another thread piggyback onto this
+ * transaction. Keep doing that while new threads continue to
+ * arrive. It doesn't cost much - we're about to run a commit
+ * and sleep on IO anyway. Speeds up many-threaded, many-dir
+ * operations by 30x or more...
+ *
+ * We try and optimize the sleep time against what the
+ * underlying disk can do, instead of having a static sleep
+ * time. This is useful for the case where our storage is so
+ * fast that it is more optimal to go ahead and force a flush
+ * and wait for the transaction to be committed than it is to
+ * wait for an arbitrary amount of time for new writers to
+ * join the transaction. We achieve this by measuring how
+ * long it takes to commit a transaction, and compare it with
+ * how long this transaction has been running, and if run time
+ * < commit time then we sleep for the delta and commit. This
+ * greatly helps super fast disks that would see slowdowns as
+ * more threads started doing fsyncs.
+ *
+ * But don't do this if this process was the most recent one
+ * to perform a synchronous write. We do this to detect the
+ * case where a single process is doing a stream of sync
+ * writes. No point in waiting for joiners in that case.
+ *
+ * Setting max_batch_time to 0 disables this completely.
+ */
+ pid = current->pid;
+ if (handle->h_sync && journal->j_last_sync_writer != pid &&
+ journal->j_max_batch_time) {
+ u64 commit_time, trans_time;
+
+ journal->j_last_sync_writer = pid;
+
+ read_lock(&journal->j_state_lock);
+ commit_time = journal->j_average_commit_time;
+ read_unlock(&journal->j_state_lock);
+
+ trans_time = ktime_to_ns(ktime_sub(ktime_get(),
+ transaction->t_start_time));
+
+ commit_time = max_t(u64, commit_time,
+ 1000*journal->j_min_batch_time);
+ commit_time = min_t(u64, commit_time,
+ 1000*journal->j_max_batch_time);
+
+ if (trans_time < commit_time) {
+ ktime_t expires = ktime_add_ns(ktime_get(),
+ commit_time);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
+ }
+ }
+
+ if (handle->h_sync)
+ transaction->t_synchronous_commit = 1;
+ current->journal_info = NULL;
+ atomic_sub(handle->h_buffer_credits,
+ &transaction->t_outstanding_credits);
+
+ /*
+ * If the handle is marked SYNC, we need to set another commit
+ * going! We also want to force a commit if the current
+ * transaction is occupying too much of the log, or if the
+ * transaction is too old now.
+ */
+ if (handle->h_sync ||
+ (atomic_read(&transaction->t_outstanding_credits) >
+ journal->j_max_transaction_buffers) ||
+ time_after_eq(jiffies, transaction->t_expires)) {
+ /* Do this even for aborted journals: an abort still
+ * completes the commit thread, it just doesn't write
+ * anything to disk. */
+
+ jbd_debug(2, "transaction too old, requesting commit for "
+ "handle %p\n", handle);
+ /* This is non-blocking */
+ jbd2_log_start_commit(journal, transaction->t_tid);
+
+ /*
+ * Special case: JBD2_SYNC synchronous updates require us
+ * to wait for the commit to complete.
+ */
+ if (handle->h_sync && !(current->flags & PF_MEMALLOC))
+ wait_for_commit = 1;
+ }
+
+ /*
+ * Once we drop t_updates, if it goes to zero the transaction
+ * could start committing on us and eventually disappear. So
+ * once we do this, we must not dereference transaction
+ * pointer again.
+ */
+ tid = transaction->t_tid;
+ if (atomic_dec_and_test(&transaction->t_updates)) {
+ wake_up(&journal->j_wait_updates);
+ if (journal->j_barrier_count)
+ wake_up(&journal->j_wait_transaction_locked);
+ }
+
+ rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_);
+
+ if (wait_for_commit)
+ err = jbd2_log_wait_commit(journal, tid);
+
+ if (handle->h_rsv_handle)
+ jbd2_journal_free_reserved(handle->h_rsv_handle);
+free_and_exit:
+ /*
+ * Scope of the GFP_NOFS context is over here and so we can restore the
+ * original alloc context.
+ */
+ memalloc_nofs_restore(handle->saved_alloc_context);
+ jbd2_free_handle(handle);
+ return err;
+}
+
+/*
+ *
+ * List management code snippets: various functions for manipulating the
+ * transaction buffer lists.
+ *
+ */
+
+/*
+ * Append a buffer to a transaction list, given the transaction's list head
+ * pointer.
+ *
+ * j_list_lock is held.
+ *
+ * jbd_lock_bh_state(jh2bh(jh)) is held.
+ */
+
+static inline void
+__blist_add_buffer(struct journal_head **list, struct journal_head *jh)
+{
+ if (!*list) {
+ jh->b_tnext = jh->b_tprev = jh;
+ *list = jh;
+ } else {
+ /* Insert at the tail of the list to preserve order */
+ struct journal_head *first = *list, *last = first->b_tprev;
+ jh->b_tprev = last;
+ jh->b_tnext = first;
+ last->b_tnext = first->b_tprev = jh;
+ }
+}
+
+/*
+ * Remove a buffer from a transaction list, given the transaction's list
+ * head pointer.
+ *
+ * Called with j_list_lock held, and the journal may not be locked.
+ *
+ * jbd_lock_bh_state(jh2bh(jh)) is held.
+ */
+
+static inline void
+__blist_del_buffer(struct journal_head **list, struct journal_head *jh)
+{
+ if (*list == jh) {
+ *list = jh->b_tnext;
+ if (*list == jh)
+ *list = NULL;
+ }
+ jh->b_tprev->b_tnext = jh->b_tnext;
+ jh->b_tnext->b_tprev = jh->b_tprev;
+}
+
+/*
+ * Remove a buffer from the appropriate transaction list.
+ *
+ * Note that this function can *change* the value of
+ * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or
+ * t_reserved_list. If the caller is holding onto a copy of one of these
+ * pointers, it could go bad. Generally the caller needs to re-read the
+ * pointer from the transaction_t.
+ *
+ * Called under j_list_lock.
+ */
+static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
+{
+ struct journal_head **list = NULL;
+ transaction_t *transaction;
+ struct buffer_head *bh = jh2bh(jh);
+
+ J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+ transaction = jh->b_transaction;
+ if (transaction)
+ assert_spin_locked(&transaction->t_journal->j_list_lock);
+
+ J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
+ if (jh->b_jlist != BJ_None)
+ J_ASSERT_JH(jh, transaction != NULL);
+
+ switch (jh->b_jlist) {
+ case BJ_None:
+ return;
+ case BJ_Metadata:
+ transaction->t_nr_buffers--;
+ J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
+ list = &transaction->t_buffers;
+ break;
+ case BJ_Forget:
+ list = &transaction->t_forget;
+ break;
+ case BJ_Shadow:
+ list = &transaction->t_shadow_list;
+ break;
+ case BJ_Reserved:
+ list = &transaction->t_reserved_list;
+ break;
+ }
+
+ __blist_del_buffer(list, jh);
+ jh->b_jlist = BJ_None;
+ if (transaction && is_journal_aborted(transaction->t_journal))
+ clear_buffer_jbddirty(bh);
+ else if (test_clear_buffer_jbddirty(bh))
+ mark_buffer_dirty(bh); /* Expose it to the VM */
+}
+
+/*
+ * Remove buffer from all transactions.
+ *
+ * Called with bh_state lock and j_list_lock
+ *
+ * jh and bh may be already freed when this function returns.
+ */
+static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
+{
+ __jbd2_journal_temp_unlink_buffer(jh);
+ jh->b_transaction = NULL;
+ jbd2_journal_put_journal_head(jh);
+}
+
+void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ /* Get reference so that buffer cannot be freed before we unlock it */
+ get_bh(bh);
+ jbd_lock_bh_state(bh);
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_unfile_buffer(jh);
+ spin_unlock(&journal->j_list_lock);
+ jbd_unlock_bh_state(bh);
+ __brelse(bh);
+}
+
+/*
+ * Called from jbd2_journal_try_to_free_buffers().
+ *
+ * Called under jbd_lock_bh_state(bh)
+ */
+static void
+__journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
+{
+ struct journal_head *jh;
+
+ jh = bh2jh(bh);
+
+ if (buffer_locked(bh) || buffer_dirty(bh))
+ goto out;
+
+ if (jh->b_next_transaction != NULL || jh->b_transaction != NULL)
+ goto out;
+
+ spin_lock(&journal->j_list_lock);
+ if (jh->b_cp_transaction != NULL) {
+ /* written-back checkpointed metadata buffer */
+ JBUFFER_TRACE(jh, "remove from checkpoint list");
+ __jbd2_journal_remove_checkpoint(jh);
+ }
+ spin_unlock(&journal->j_list_lock);
+out:
+ return;
+}
+
+/**
+ * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
+ * @journal: journal for operation
+ * @page: to try and free
+ * @gfp_mask: we use the mask to detect how hard should we try to release
+ * buffers. If __GFP_DIRECT_RECLAIM and __GFP_FS is set, we wait for commit
+ * code to release the buffers.
+ *
+ *
+ * For all the buffers on this page,
+ * if they are fully written out ordered data, move them onto BUF_CLEAN
+ * so try_to_free_buffers() can reap them.
+ *
+ * This function returns non-zero if we wish try_to_free_buffers()
+ * to be called. We do this if the page is releasable by try_to_free_buffers().
+ * We also do it if the page has locked or dirty buffers and the caller wants
+ * us to perform sync or async writeout.
+ *
+ * This complicates JBD locking somewhat. We aren't protected by the
+ * BKL here. We wish to remove the buffer from its committing or
+ * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer.
+ *
+ * This may *change* the value of transaction_t->t_datalist, so anyone
+ * who looks at t_datalist needs to lock against this function.
+ *
+ * Even worse, someone may be doing a jbd2_journal_dirty_data on this
+ * buffer. So we need to lock against that. jbd2_journal_dirty_data()
+ * will come out of the lock with the buffer dirty, which makes it
+ * ineligible for release here.
+ *
+ * Who else is affected by this? hmm... Really the only contender
+ * is do_get_write_access() - it could be looking at the buffer while
+ * journal_try_to_free_buffer() is changing its state. But that
+ * cannot happen because we never reallocate freed data as metadata
+ * while the data is part of a transaction. Yes?
+ *
+ * Return 0 on failure, 1 on success
+ */
+int jbd2_journal_try_to_free_buffers(journal_t *journal,
+ struct page *page, gfp_t gfp_mask)
+{
+ struct buffer_head *head;
+ struct buffer_head *bh;
+ int ret = 0;
+
+ J_ASSERT(PageLocked(page));
+
+ head = page_buffers(page);
+ bh = head;
+ do {
+ struct journal_head *jh;
+
+ /*
+ * We take our own ref against the journal_head here to avoid
+ * having to add tons of locking around each instance of
+ * jbd2_journal_put_journal_head().
+ */
+ jh = jbd2_journal_grab_journal_head(bh);
+ if (!jh)
+ continue;
+
+ jbd_lock_bh_state(bh);
+ __journal_try_to_free_buffer(journal, bh);
+ jbd2_journal_put_journal_head(jh);
+ jbd_unlock_bh_state(bh);
+ if (buffer_jbd(bh))
+ goto busy;
+ } while ((bh = bh->b_this_page) != head);
+
+ ret = try_to_free_buffers(page);
+
+busy:
+ return ret;
+}
+
+/*
+ * This buffer is no longer needed. If it is on an older transaction's
+ * checkpoint list we need to record it on this transaction's forget list
+ * to pin this buffer (and hence its checkpointing transaction) down until
+ * this transaction commits. If the buffer isn't on a checkpoint list, we
+ * release it.
+ * Returns non-zero if JBD no longer has an interest in the buffer.
+ *
+ * Called under j_list_lock.
+ *
+ * Called under jbd_lock_bh_state(bh).
+ */
+static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
+{
+ int may_free = 1;
+ struct buffer_head *bh = jh2bh(jh);
+
+ if (jh->b_cp_transaction) {
+ JBUFFER_TRACE(jh, "on running+cp transaction");
+ __jbd2_journal_temp_unlink_buffer(jh);
+ /*
+ * We don't want to write the buffer anymore, clear the
+ * bit so that we don't confuse checks in
+ * __journal_file_buffer
+ */
+ clear_buffer_dirty(bh);
+ __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
+ may_free = 0;
+ } else {
+ JBUFFER_TRACE(jh, "on running transaction");
+ __jbd2_journal_unfile_buffer(jh);
+ }
+ return may_free;
+}
+
+/*
+ * jbd2_journal_invalidatepage
+ *
+ * This code is tricky. It has a number of cases to deal with.
+ *
+ * There are two invariants which this code relies on:
+ *
+ * i_size must be updated on disk before we start calling invalidatepage on the
+ * data.
+ *
+ * This is done in ext3 by defining an ext3_setattr method which
+ * updates i_size before truncate gets going. By maintaining this
+ * invariant, we can be sure that it is safe to throw away any buffers
+ * attached to the current transaction: once the transaction commits,
+ * we know that the data will not be needed.
+ *
+ * Note however that we can *not* throw away data belonging to the
+ * previous, committing transaction!
+ *
+ * Any disk blocks which *are* part of the previous, committing
+ * transaction (and which therefore cannot be discarded immediately) are
+ * not going to be reused in the new running transaction
+ *
+ * The bitmap committed_data images guarantee this: any block which is
+ * allocated in one transaction and removed in the next will be marked
+ * as in-use in the committed_data bitmap, so cannot be reused until
+ * the next transaction to delete the block commits. This means that
+ * leaving committing buffers dirty is quite safe: the disk blocks
+ * cannot be reallocated to a different file and so buffer aliasing is
+ * not possible.
+ *
+ *
+ * The above applies mainly to ordered data mode. In writeback mode we
+ * don't make guarantees about the order in which data hits disk --- in
+ * particular we don't guarantee that new dirty data is flushed before
+ * transaction commit --- so it is always safe just to discard data
+ * immediately in that mode. --sct
+ */
+
+/*
+ * The journal_unmap_buffer helper function returns zero if the buffer
+ * concerned remains pinned as an anonymous buffer belonging to an older
+ * transaction.
+ *
+ * We're outside-transaction here. Either or both of j_running_transaction
+ * and j_committing_transaction may be NULL.
+ */
+static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
+ int partial_page)
+{
+ transaction_t *transaction;
+ struct journal_head *jh;
+ int may_free = 1;
+
+ BUFFER_TRACE(bh, "entry");
+
+ /*
+ * It is safe to proceed here without the j_list_lock because the
+ * buffers cannot be stolen by try_to_free_buffers as long as we are
+ * holding the page lock. --sct
+ */
+
+ if (!buffer_jbd(bh))
+ goto zap_buffer_unlocked;
+
+ /* OK, we have data buffer in journaled mode */
+ write_lock(&journal->j_state_lock);
+ jbd_lock_bh_state(bh);
+ spin_lock(&journal->j_list_lock);
+
+ jh = jbd2_journal_grab_journal_head(bh);
+ if (!jh)
+ goto zap_buffer_no_jh;
+
+ /*
+ * We cannot remove the buffer from checkpoint lists until the
+ * transaction adding inode to orphan list (let's call it T)
+ * is committed. Otherwise if the transaction changing the
+ * buffer would be cleaned from the journal before T is
+ * committed, a crash will cause that the correct contents of
+ * the buffer will be lost. On the other hand we have to
+ * clear the buffer dirty bit at latest at the moment when the
+ * transaction marking the buffer as freed in the filesystem
+ * structures is committed because from that moment on the
+ * block can be reallocated and used by a different page.
+ * Since the block hasn't been freed yet but the inode has
+ * already been added to orphan list, it is safe for us to add
+ * the buffer to BJ_Forget list of the newest transaction.
+ *
+ * Also we have to clear buffer_mapped flag of a truncated buffer
+ * because the buffer_head may be attached to the page straddling
+ * i_size (can happen only when blocksize < pagesize) and thus the
+ * buffer_head can be reused when the file is extended again. So we end
+ * up keeping around invalidated buffers attached to transactions'
+ * BJ_Forget list just to stop checkpointing code from cleaning up
+ * the transaction this buffer was modified in.
+ */
+ transaction = jh->b_transaction;
+ if (transaction == NULL) {
+ /* First case: not on any transaction. If it
+ * has no checkpoint link, then we can zap it:
+ * it's a writeback-mode buffer so we don't care
+ * if it hits disk safely. */
+ if (!jh->b_cp_transaction) {
+ JBUFFER_TRACE(jh, "not on any transaction: zap");
+ goto zap_buffer;
+ }
+
+ if (!buffer_dirty(bh)) {
+ /* bdflush has written it. We can drop it now */
+ __jbd2_journal_remove_checkpoint(jh);
+ goto zap_buffer;
+ }
+
+ /* OK, it must be in the journal but still not
+ * written fully to disk: it's metadata or
+ * journaled data... */
+
+ if (journal->j_running_transaction) {
+ /* ... and once the current transaction has
+ * committed, the buffer won't be needed any
+ * longer. */
+ JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget");
+ may_free = __dispose_buffer(jh,
+ journal->j_running_transaction);
+ goto zap_buffer;
+ } else {
+ /* There is no currently-running transaction. So the
+ * orphan record which we wrote for this file must have
+ * passed into commit. We must attach this buffer to
+ * the committing transaction, if it exists. */
+ if (journal->j_committing_transaction) {
+ JBUFFER_TRACE(jh, "give to committing trans");
+ may_free = __dispose_buffer(jh,
+ journal->j_committing_transaction);
+ goto zap_buffer;
+ } else {
+ /* The orphan record's transaction has
+ * committed. We can cleanse this buffer */
+ clear_buffer_jbddirty(bh);
+ __jbd2_journal_remove_checkpoint(jh);
+ goto zap_buffer;
+ }
+ }
+ } else if (transaction == journal->j_committing_transaction) {
+ JBUFFER_TRACE(jh, "on committing transaction");
+ /*
+ * The buffer is committing, we simply cannot touch
+ * it. If the page is straddling i_size we have to wait
+ * for commit and try again.
+ */
+ if (partial_page) {
+ jbd2_journal_put_journal_head(jh);
+ spin_unlock(&journal->j_list_lock);
+ jbd_unlock_bh_state(bh);
+ write_unlock(&journal->j_state_lock);
+ return -EBUSY;
+ }
+ /*
+ * OK, buffer won't be reachable after truncate. We just set
+ * j_next_transaction to the running transaction (if there is
+ * one) and mark buffer as freed so that commit code knows it
+ * should clear dirty bits when it is done with the buffer.
+ */
+ set_buffer_freed(bh);
+ if (journal->j_running_transaction && buffer_jbddirty(bh))
+ jh->b_next_transaction = journal->j_running_transaction;
+ jbd2_journal_put_journal_head(jh);
+ spin_unlock(&journal->j_list_lock);
+ jbd_unlock_bh_state(bh);
+ write_unlock(&journal->j_state_lock);
+ return 0;
+ } else {
+ /* Good, the buffer belongs to the running transaction.
+ * We are writing our own transaction's data, not any
+ * previous one's, so it is safe to throw it away
+ * (remember that we expect the filesystem to have set
+ * i_size already for this truncate so recovery will not
+ * expose the disk blocks we are discarding here.) */
+ J_ASSERT_JH(jh, transaction == journal->j_running_transaction);
+ JBUFFER_TRACE(jh, "on running transaction");
+ may_free = __dispose_buffer(jh, transaction);
+ }
+
+zap_buffer:
+ /*
+ * This is tricky. Although the buffer is truncated, it may be reused
+ * if blocksize < pagesize and it is attached to the page straddling
+ * EOF. Since the buffer might have been added to BJ_Forget list of the
+ * running transaction, journal_get_write_access() won't clear
+ * b_modified and credit accounting gets confused. So clear b_modified
+ * here.
+ */
+ jh->b_modified = 0;
+ jbd2_journal_put_journal_head(jh);
+zap_buffer_no_jh:
+ spin_unlock(&journal->j_list_lock);
+ jbd_unlock_bh_state(bh);
+ write_unlock(&journal->j_state_lock);
+zap_buffer_unlocked:
+ clear_buffer_dirty(bh);
+ J_ASSERT_BH(bh, !buffer_jbddirty(bh));
+ clear_buffer_mapped(bh);
+ clear_buffer_req(bh);
+ clear_buffer_new(bh);
+ clear_buffer_delay(bh);
+ clear_buffer_unwritten(bh);
+ bh->b_bdev = NULL;
+ return may_free;
+}
+
+/**
+ * void jbd2_journal_invalidatepage()
+ * @journal: journal to use for flush...
+ * @page: page to flush
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
+ *
+ * Reap page buffers containing data after in the specified range in page.
+ * Can return -EBUSY if buffers are part of the committing transaction and
+ * the page is straddling i_size. Caller then has to wait for current commit
+ * and try again.
+ */
+int jbd2_journal_invalidatepage(journal_t *journal,
+ struct page *page,
+ unsigned int offset,
+ unsigned int length)
+{
+ struct buffer_head *head, *bh, *next;
+ unsigned int stop = offset + length;
+ unsigned int curr_off = 0;
+ int partial_page = (offset || length < PAGE_SIZE);
+ int may_free = 1;
+ int ret = 0;
+
+ if (!PageLocked(page))
+ BUG();
+ if (!page_has_buffers(page))
+ return 0;
+
+ BUG_ON(stop > PAGE_SIZE || stop < length);
+
+ /* We will potentially be playing with lists other than just the
+ * data lists (especially for journaled data mode), so be
+ * cautious in our locking. */
+
+ head = bh = page_buffers(page);
+ do {
+ unsigned int next_off = curr_off + bh->b_size;
+ next = bh->b_this_page;
+
+ if (next_off > stop)
+ return 0;
+
+ if (offset <= curr_off) {
+ /* This block is wholly outside the truncation point */
+ lock_buffer(bh);
+ ret = journal_unmap_buffer(journal, bh, partial_page);
+ unlock_buffer(bh);
+ if (ret < 0)
+ return ret;
+ may_free &= ret;
+ }
+ curr_off = next_off;
+ bh = next;
+
+ } while (bh != head);
+
+ if (!partial_page) {
+ if (may_free && try_to_free_buffers(page))
+ J_ASSERT(!page_has_buffers(page));
+ }
+ return 0;
+}
+
+/*
+ * File a buffer on the given transaction list.
+ */
+void __jbd2_journal_file_buffer(struct journal_head *jh,
+ transaction_t *transaction, int jlist)
+{
+ struct journal_head **list = NULL;
+ int was_dirty = 0;
+ struct buffer_head *bh = jh2bh(jh);
+
+ J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+ assert_spin_locked(&transaction->t_journal->j_list_lock);
+
+ J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
+ J_ASSERT_JH(jh, jh->b_transaction == transaction ||
+ jh->b_transaction == NULL);
+
+ if (jh->b_transaction && jh->b_jlist == jlist)
+ return;
+
+ if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
+ jlist == BJ_Shadow || jlist == BJ_Forget) {
+ /*
+ * For metadata buffers, we track dirty bit in buffer_jbddirty
+ * instead of buffer_dirty. We should not see a dirty bit set
+ * here because we clear it in do_get_write_access but e.g.
+ * tune2fs can modify the sb and set the dirty bit at any time
+ * so we try to gracefully handle that.
+ */
+ if (buffer_dirty(bh))
+ warn_dirty_buffer(bh);
+ if (test_clear_buffer_dirty(bh) ||
+ test_clear_buffer_jbddirty(bh))
+ was_dirty = 1;
+ }
+
+ if (jh->b_transaction)
+ __jbd2_journal_temp_unlink_buffer(jh);
+ else
+ jbd2_journal_grab_journal_head(bh);
+ jh->b_transaction = transaction;
+
+ switch (jlist) {
+ case BJ_None:
+ J_ASSERT_JH(jh, !jh->b_committed_data);
+ J_ASSERT_JH(jh, !jh->b_frozen_data);
+ return;
+ case BJ_Metadata:
+ transaction->t_nr_buffers++;
+ list = &transaction->t_buffers;
+ break;
+ case BJ_Forget:
+ list = &transaction->t_forget;
+ break;
+ case BJ_Shadow:
+ list = &transaction->t_shadow_list;
+ break;
+ case BJ_Reserved:
+ list = &transaction->t_reserved_list;
+ break;
+ }
+
+ __blist_add_buffer(list, jh);
+ jh->b_jlist = jlist;
+
+ if (was_dirty)
+ set_buffer_jbddirty(bh);
+}
+
+void jbd2_journal_file_buffer(struct journal_head *jh,
+ transaction_t *transaction, int jlist)
+{
+ jbd_lock_bh_state(jh2bh(jh));
+ spin_lock(&transaction->t_journal->j_list_lock);
+ __jbd2_journal_file_buffer(jh, transaction, jlist);
+ spin_unlock(&transaction->t_journal->j_list_lock);
+ jbd_unlock_bh_state(jh2bh(jh));
+}
+
+/*
+ * Remove a buffer from its current buffer list in preparation for
+ * dropping it from its current transaction entirely. If the buffer has
+ * already started to be used by a subsequent transaction, refile the
+ * buffer on that transaction's metadata list.
+ *
+ * Called under j_list_lock
+ * Called under jbd_lock_bh_state(jh2bh(jh))
+ *
+ * jh and bh may be already free when this function returns
+ */
+void __jbd2_journal_refile_buffer(struct journal_head *jh)
+{
+ int was_dirty, jlist;
+ struct buffer_head *bh = jh2bh(jh);
+
+ J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+ if (jh->b_transaction)
+ assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
+
+ /* If the buffer is now unused, just drop it. */
+ if (jh->b_next_transaction == NULL) {
+ __jbd2_journal_unfile_buffer(jh);
+ return;
+ }
+
+ /*
+ * It has been modified by a later transaction: add it to the new
+ * transaction's metadata list.
+ */
+
+ was_dirty = test_clear_buffer_jbddirty(bh);
+ __jbd2_journal_temp_unlink_buffer(jh);
+ /*
+ * We set b_transaction here because b_next_transaction will inherit
+ * our jh reference and thus __jbd2_journal_file_buffer() must not
+ * take a new one.
+ */
+ jh->b_transaction = jh->b_next_transaction;
+ jh->b_next_transaction = NULL;
+ if (buffer_freed(bh))
+ jlist = BJ_Forget;
+ else if (jh->b_modified)
+ jlist = BJ_Metadata;
+ else
+ jlist = BJ_Reserved;
+ __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist);
+ J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
+
+ if (was_dirty)
+ set_buffer_jbddirty(bh);
+}
+
+/*
+ * __jbd2_journal_refile_buffer() with necessary locking added. We take our
+ * bh reference so that we can safely unlock bh.
+ *
+ * The jh and bh may be freed by this call.
+ */
+void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ /* Get reference so that buffer cannot be freed before we unlock it */
+ get_bh(bh);
+ jbd_lock_bh_state(bh);
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_refile_buffer(jh);
+ jbd_unlock_bh_state(bh);
+ spin_unlock(&journal->j_list_lock);
+ __brelse(bh);
+}
+
+/*
+ * File inode in the inode list of the handle's transaction
+ */
+static int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode,
+ unsigned long flags)
+{
+ transaction_t *transaction = handle->h_transaction;
+ journal_t *journal;
+
+ if (is_handle_aborted(handle))
+ return -EROFS;
+ journal = transaction->t_journal;
+
+ jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
+ transaction->t_tid);
+
+ /*
+ * First check whether inode isn't already on the transaction's
+ * lists without taking the lock. Note that this check is safe
+ * without the lock as we cannot race with somebody removing inode
+ * from the transaction. The reason is that we remove inode from the
+ * transaction only in journal_release_jbd_inode() and when we commit
+ * the transaction. We are guarded from the first case by holding
+ * a reference to the inode. We are safe against the second case
+ * because if jinode->i_transaction == transaction, commit code
+ * cannot touch the transaction because we hold reference to it,
+ * and if jinode->i_next_transaction == transaction, commit code
+ * will only file the inode where we want it.
+ */
+ if ((jinode->i_transaction == transaction ||
+ jinode->i_next_transaction == transaction) &&
+ (jinode->i_flags & flags) == flags)
+ return 0;
+
+ spin_lock(&journal->j_list_lock);
+ jinode->i_flags |= flags;
+ /* Is inode already attached where we need it? */
+ if (jinode->i_transaction == transaction ||
+ jinode->i_next_transaction == transaction)
+ goto done;
+
+ /*
+ * We only ever set this variable to 1 so the test is safe. Since
+ * t_need_data_flush is likely to be set, we do the test to save some
+ * cacheline bouncing
+ */
+ if (!transaction->t_need_data_flush)
+ transaction->t_need_data_flush = 1;
+ /* On some different transaction's list - should be
+ * the committing one */
+ if (jinode->i_transaction) {
+ J_ASSERT(jinode->i_next_transaction == NULL);
+ J_ASSERT(jinode->i_transaction ==
+ journal->j_committing_transaction);
+ jinode->i_next_transaction = transaction;
+ goto done;
+ }
+ /* Not on any transaction list... */
+ J_ASSERT(!jinode->i_next_transaction);
+ jinode->i_transaction = transaction;
+ list_add(&jinode->i_list, &transaction->t_inode_list);
+done:
+ spin_unlock(&journal->j_list_lock);
+
+ return 0;
+}
+
+int jbd2_journal_inode_add_write(handle_t *handle, struct jbd2_inode *jinode)
+{
+ return jbd2_journal_file_inode(handle, jinode,
+ JI_WRITE_DATA | JI_WAIT_DATA);
+}
+
+int jbd2_journal_inode_add_wait(handle_t *handle, struct jbd2_inode *jinode)
+{
+ return jbd2_journal_file_inode(handle, jinode, JI_WAIT_DATA);
+}
+
+/*
+ * File truncate and transaction commit interact with each other in a
+ * non-trivial way. If a transaction writing data block A is
+ * committing, we cannot discard the data by truncate until we have
+ * written them. Otherwise if we crashed after the transaction with
+ * write has committed but before the transaction with truncate has
+ * committed, we could see stale data in block A. This function is a
+ * helper to solve this problem. It starts writeout of the truncated
+ * part in case it is in the committing transaction.
+ *
+ * Filesystem code must call this function when inode is journaled in
+ * ordered mode before truncation happens and after the inode has been
+ * placed on orphan list with the new inode size. The second condition
+ * avoids the race that someone writes new data and we start
+ * committing the transaction after this function has been called but
+ * before a transaction for truncate is started (and furthermore it
+ * allows us to optimize the case where the addition to orphan list
+ * happens in the same transaction as write --- we don't have to write
+ * any data in such case).
+ */
+int jbd2_journal_begin_ordered_truncate(journal_t *journal,
+ struct jbd2_inode *jinode,
+ loff_t new_size)
+{
+ transaction_t *inode_trans, *commit_trans;
+ int ret = 0;
+
+ /* This is a quick check to avoid locking if not necessary */
+ if (!jinode->i_transaction)
+ goto out;
+ /* Locks are here just to force reading of recent values, it is
+ * enough that the transaction was not committing before we started
+ * a transaction adding the inode to orphan list */
+ read_lock(&journal->j_state_lock);
+ commit_trans = journal->j_committing_transaction;
+ read_unlock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ inode_trans = jinode->i_transaction;
+ spin_unlock(&journal->j_list_lock);
+ if (inode_trans == commit_trans) {
+ ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping,
+ new_size, LLONG_MAX);
+ if (ret)
+ jbd2_journal_abort(journal, ret);
+ }
+out:
+ return ret;
+}