v4.19.13 snapshot.
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
new file mode 100644
index 0000000..e6e925a
--- /dev/null
+++ b/drivers/md/raid5-cache.c
@@ -0,0 +1,3185 @@
+/*
+ * Copyright (C) 2015 Shaohua Li <shli@fb.com>
+ * Copyright (C) 2016 Song Liu <songliubraving@fb.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/wait.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/raid/md_p.h>
+#include <linux/crc32c.h>
+#include <linux/random.h>
+#include <linux/kthread.h>
+#include <linux/types.h>
+#include "md.h"
+#include "raid5.h"
+#include "md-bitmap.h"
+#include "raid5-log.h"
+
+/*
+ * metadata/data stored in disk with 4k size unit (a block) regardless
+ * underneath hardware sector size. only works with PAGE_SIZE == 4096
+ */
+#define BLOCK_SECTORS (8)
+#define BLOCK_SECTOR_SHIFT (3)
+
+/*
+ * log->max_free_space is min(1/4 disk size, 10G reclaimable space).
+ *
+ * In write through mode, the reclaim runs every log->max_free_space.
+ * This can prevent the recovery scans for too long
+ */
+#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */
+#define RECLAIM_MAX_FREE_SPACE_SHIFT (2)
+
+/* wake up reclaim thread periodically */
+#define R5C_RECLAIM_WAKEUP_INTERVAL (30 * HZ)
+/* start flush with these full stripes */
+#define R5C_FULL_STRIPE_FLUSH_BATCH(conf) (conf->max_nr_stripes / 4)
+/* reclaim stripes in groups */
+#define R5C_RECLAIM_STRIPE_GROUP (NR_STRIPE_HASH_LOCKS * 2)
+
+/*
+ * We only need 2 bios per I/O unit to make progress, but ensure we
+ * have a few more available to not get too tight.
+ */
+#define R5L_POOL_SIZE 4
+
+static char *r5c_journal_mode_str[] = {"write-through",
+ "write-back"};
+/*
+ * raid5 cache state machine
+ *
+ * With the RAID cache, each stripe works in two phases:
+ * - caching phase
+ * - writing-out phase
+ *
+ * These two phases are controlled by bit STRIPE_R5C_CACHING:
+ * if STRIPE_R5C_CACHING == 0, the stripe is in writing-out phase
+ * if STRIPE_R5C_CACHING == 1, the stripe is in caching phase
+ *
+ * When there is no journal, or the journal is in write-through mode,
+ * the stripe is always in writing-out phase.
+ *
+ * For write-back journal, the stripe is sent to caching phase on write
+ * (r5c_try_caching_write). r5c_make_stripe_write_out() kicks off
+ * the write-out phase by clearing STRIPE_R5C_CACHING.
+ *
+ * Stripes in caching phase do not write the raid disks. Instead, all
+ * writes are committed from the log device. Therefore, a stripe in
+ * caching phase handles writes as:
+ * - write to log device
+ * - return IO
+ *
+ * Stripes in writing-out phase handle writes as:
+ * - calculate parity
+ * - write pending data and parity to journal
+ * - write data and parity to raid disks
+ * - return IO for pending writes
+ */
+
+struct r5l_log {
+ struct md_rdev *rdev;
+
+ u32 uuid_checksum;
+
+ sector_t device_size; /* log device size, round to
+ * BLOCK_SECTORS */
+ sector_t max_free_space; /* reclaim run if free space is at
+ * this size */
+
+ sector_t last_checkpoint; /* log tail. where recovery scan
+ * starts from */
+ u64 last_cp_seq; /* log tail sequence */
+
+ sector_t log_start; /* log head. where new data appends */
+ u64 seq; /* log head sequence */
+
+ sector_t next_checkpoint;
+
+ struct mutex io_mutex;
+ struct r5l_io_unit *current_io; /* current io_unit accepting new data */
+
+ spinlock_t io_list_lock;
+ struct list_head running_ios; /* io_units which are still running,
+ * and have not yet been completely
+ * written to the log */
+ struct list_head io_end_ios; /* io_units which have been completely
+ * written to the log but not yet written
+ * to the RAID */
+ struct list_head flushing_ios; /* io_units which are waiting for log
+ * cache flush */
+ struct list_head finished_ios; /* io_units which settle down in log disk */
+ struct bio flush_bio;
+
+ struct list_head no_mem_stripes; /* pending stripes, -ENOMEM */
+
+ struct kmem_cache *io_kc;
+ mempool_t io_pool;
+ struct bio_set bs;
+ mempool_t meta_pool;
+
+ struct md_thread *reclaim_thread;
+ unsigned long reclaim_target; /* number of space that need to be
+ * reclaimed. if it's 0, reclaim spaces
+ * used by io_units which are in
+ * IO_UNIT_STRIPE_END state (eg, reclaim
+ * dones't wait for specific io_unit
+ * switching to IO_UNIT_STRIPE_END
+ * state) */
+ wait_queue_head_t iounit_wait;
+
+ struct list_head no_space_stripes; /* pending stripes, log has no space */
+ spinlock_t no_space_stripes_lock;
+
+ bool need_cache_flush;
+
+ /* for r5c_cache */
+ enum r5c_journal_mode r5c_journal_mode;
+
+ /* all stripes in r5cache, in the order of seq at sh->log_start */
+ struct list_head stripe_in_journal_list;
+
+ spinlock_t stripe_in_journal_lock;
+ atomic_t stripe_in_journal_count;
+
+ /* to submit async io_units, to fulfill ordering of flush */
+ struct work_struct deferred_io_work;
+ /* to disable write back during in degraded mode */
+ struct work_struct disable_writeback_work;
+
+ /* to for chunk_aligned_read in writeback mode, details below */
+ spinlock_t tree_lock;
+ struct radix_tree_root big_stripe_tree;
+};
+
+/*
+ * Enable chunk_aligned_read() with write back cache.
+ *
+ * Each chunk may contain more than one stripe (for example, a 256kB
+ * chunk contains 64 4kB-page, so this chunk contain 64 stripes). For
+ * chunk_aligned_read, these stripes are grouped into one "big_stripe".
+ * For each big_stripe, we count how many stripes of this big_stripe
+ * are in the write back cache. These data are tracked in a radix tree
+ * (big_stripe_tree). We use radix_tree item pointer as the counter.
+ * r5c_tree_index() is used to calculate keys for the radix tree.
+ *
+ * chunk_aligned_read() calls r5c_big_stripe_cached() to look up
+ * big_stripe of each chunk in the tree. If this big_stripe is in the
+ * tree, chunk_aligned_read() aborts. This look up is protected by
+ * rcu_read_lock().
+ *
+ * It is necessary to remember whether a stripe is counted in
+ * big_stripe_tree. Instead of adding new flag, we reuses existing flags:
+ * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these
+ * two flags are set, the stripe is counted in big_stripe_tree. This
+ * requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to
+ * r5c_try_caching_write(); and moving clear_bit of
+ * STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to
+ * r5c_finish_stripe_write_out().
+ */
+
+/*
+ * radix tree requests lowest 2 bits of data pointer to be 2b'00.
+ * So it is necessary to left shift the counter by 2 bits before using it
+ * as data pointer of the tree.
+ */
+#define R5C_RADIX_COUNT_SHIFT 2
+
+/*
+ * calculate key for big_stripe_tree
+ *
+ * sect: align_bi->bi_iter.bi_sector or sh->sector
+ */
+static inline sector_t r5c_tree_index(struct r5conf *conf,
+ sector_t sect)
+{
+ sector_t offset;
+
+ offset = sector_div(sect, conf->chunk_sectors);
+ return sect;
+}
+
+/*
+ * an IO range starts from a meta data block and end at the next meta data
+ * block. The io unit's the meta data block tracks data/parity followed it. io
+ * unit is written to log disk with normal write, as we always flush log disk
+ * first and then start move data to raid disks, there is no requirement to
+ * write io unit with FLUSH/FUA
+ */
+struct r5l_io_unit {
+ struct r5l_log *log;
+
+ struct page *meta_page; /* store meta block */
+ int meta_offset; /* current offset in meta_page */
+
+ struct bio *current_bio;/* current_bio accepting new data */
+
+ atomic_t pending_stripe;/* how many stripes not flushed to raid */
+ u64 seq; /* seq number of the metablock */
+ sector_t log_start; /* where the io_unit starts */
+ sector_t log_end; /* where the io_unit ends */
+ struct list_head log_sibling; /* log->running_ios */
+ struct list_head stripe_list; /* stripes added to the io_unit */
+
+ int state;
+ bool need_split_bio;
+ struct bio *split_bio;
+
+ unsigned int has_flush:1; /* include flush request */
+ unsigned int has_fua:1; /* include fua request */
+ unsigned int has_null_flush:1; /* include null flush request */
+ unsigned int has_flush_payload:1; /* include flush payload */
+ /*
+ * io isn't sent yet, flush/fua request can only be submitted till it's
+ * the first IO in running_ios list
+ */
+ unsigned int io_deferred:1;
+
+ struct bio_list flush_barriers; /* size == 0 flush bios */
+};
+
+/* r5l_io_unit state */
+enum r5l_io_unit_state {
+ IO_UNIT_RUNNING = 0, /* accepting new IO */
+ IO_UNIT_IO_START = 1, /* io_unit bio start writing to log,
+ * don't accepting new bio */
+ IO_UNIT_IO_END = 2, /* io_unit bio finish writing to log */
+ IO_UNIT_STRIPE_END = 3, /* stripes data finished writing to raid */
+};
+
+bool r5c_is_writeback(struct r5l_log *log)
+{
+ return (log != NULL &&
+ log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK);
+}
+
+static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
+{
+ start += inc;
+ if (start >= log->device_size)
+ start = start - log->device_size;
+ return start;
+}
+
+static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start,
+ sector_t end)
+{
+ if (end >= start)
+ return end - start;
+ else
+ return end + log->device_size - start;
+}
+
+static bool r5l_has_free_space(struct r5l_log *log, sector_t size)
+{
+ sector_t used_size;
+
+ used_size = r5l_ring_distance(log, log->last_checkpoint,
+ log->log_start);
+
+ return log->device_size > used_size + size;
+}
+
+static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
+ enum r5l_io_unit_state state)
+{
+ if (WARN_ON(io->state >= state))
+ return;
+ io->state = state;
+}
+
+static void
+r5c_return_dev_pending_writes(struct r5conf *conf, struct r5dev *dev)
+{
+ struct bio *wbi, *wbi2;
+
+ wbi = dev->written;
+ dev->written = NULL;
+ while (wbi && wbi->bi_iter.bi_sector <
+ dev->sector + STRIPE_SECTORS) {
+ wbi2 = r5_next_bio(wbi, dev->sector);
+ md_write_end(conf->mddev);
+ bio_endio(wbi);
+ wbi = wbi2;
+ }
+}
+
+void r5c_handle_cached_data_endio(struct r5conf *conf,
+ struct stripe_head *sh, int disks)
+{
+ int i;
+
+ for (i = sh->disks; i--; ) {
+ if (sh->dev[i].written) {
+ set_bit(R5_UPTODATE, &sh->dev[i].flags);
+ r5c_return_dev_pending_writes(conf, &sh->dev[i]);
+ md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
+ STRIPE_SECTORS,
+ !test_bit(STRIPE_DEGRADED, &sh->state),
+ 0);
+ }
+ }
+}
+
+void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
+
+/* Check whether we should flush some stripes to free up stripe cache */
+void r5c_check_stripe_cache_usage(struct r5conf *conf)
+{
+ int total_cached;
+
+ if (!r5c_is_writeback(conf->log))
+ return;
+
+ total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
+ atomic_read(&conf->r5c_cached_full_stripes);
+
+ /*
+ * The following condition is true for either of the following:
+ * - stripe cache pressure high:
+ * total_cached > 3/4 min_nr_stripes ||
+ * empty_inactive_list_nr > 0
+ * - stripe cache pressure moderate:
+ * total_cached > 1/2 min_nr_stripes
+ */
+ if (total_cached > conf->min_nr_stripes * 1 / 2 ||
+ atomic_read(&conf->empty_inactive_list_nr) > 0)
+ r5l_wake_reclaim(conf->log, 0);
+}
+
+/*
+ * flush cache when there are R5C_FULL_STRIPE_FLUSH_BATCH or more full
+ * stripes in the cache
+ */
+void r5c_check_cached_full_stripe(struct r5conf *conf)
+{
+ if (!r5c_is_writeback(conf->log))
+ return;
+
+ /*
+ * wake up reclaim for R5C_FULL_STRIPE_FLUSH_BATCH cached stripes
+ * or a full stripe (chunk size / 4k stripes).
+ */
+ if (atomic_read(&conf->r5c_cached_full_stripes) >=
+ min(R5C_FULL_STRIPE_FLUSH_BATCH(conf),
+ conf->chunk_sectors >> STRIPE_SHIFT))
+ r5l_wake_reclaim(conf->log, 0);
+}
+
+/*
+ * Total log space (in sectors) needed to flush all data in cache
+ *
+ * To avoid deadlock due to log space, it is necessary to reserve log
+ * space to flush critical stripes (stripes that occupying log space near
+ * last_checkpoint). This function helps check how much log space is
+ * required to flush all cached stripes.
+ *
+ * To reduce log space requirements, two mechanisms are used to give cache
+ * flush higher priorities:
+ * 1. In handle_stripe_dirtying() and schedule_reconstruction(),
+ * stripes ALREADY in journal can be flushed w/o pending writes;
+ * 2. In r5l_write_stripe() and r5c_cache_data(), stripes NOT in journal
+ * can be delayed (r5l_add_no_space_stripe).
+ *
+ * In cache flush, the stripe goes through 1 and then 2. For a stripe that
+ * already passed 1, flushing it requires at most (conf->max_degraded + 1)
+ * pages of journal space. For stripes that has not passed 1, flushing it
+ * requires (conf->raid_disks + 1) pages of journal space. There are at
+ * most (conf->group_cnt + 1) stripe that passed 1. So total journal space
+ * required to flush all cached stripes (in pages) is:
+ *
+ * (stripe_in_journal_count - group_cnt - 1) * (max_degraded + 1) +
+ * (group_cnt + 1) * (raid_disks + 1)
+ * or
+ * (stripe_in_journal_count) * (max_degraded + 1) +
+ * (group_cnt + 1) * (raid_disks - max_degraded)
+ */
+static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf)
+{
+ struct r5l_log *log = conf->log;
+
+ if (!r5c_is_writeback(log))
+ return 0;
+
+ return BLOCK_SECTORS *
+ ((conf->max_degraded + 1) * atomic_read(&log->stripe_in_journal_count) +
+ (conf->raid_disks - conf->max_degraded) * (conf->group_cnt + 1));
+}
+
+/*
+ * evaluate log space usage and update R5C_LOG_TIGHT and R5C_LOG_CRITICAL
+ *
+ * R5C_LOG_TIGHT is set when free space on the log device is less than 3x of
+ * reclaim_required_space. R5C_LOG_CRITICAL is set when free space on the log
+ * device is less than 2x of reclaim_required_space.
+ */
+static inline void r5c_update_log_state(struct r5l_log *log)
+{
+ struct r5conf *conf = log->rdev->mddev->private;
+ sector_t free_space;
+ sector_t reclaim_space;
+ bool wake_reclaim = false;
+
+ if (!r5c_is_writeback(log))
+ return;
+
+ free_space = r5l_ring_distance(log, log->log_start,
+ log->last_checkpoint);
+ reclaim_space = r5c_log_required_to_flush_cache(conf);
+ if (free_space < 2 * reclaim_space)
+ set_bit(R5C_LOG_CRITICAL, &conf->cache_state);
+ else {
+ if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
+ wake_reclaim = true;
+ clear_bit(R5C_LOG_CRITICAL, &conf->cache_state);
+ }
+ if (free_space < 3 * reclaim_space)
+ set_bit(R5C_LOG_TIGHT, &conf->cache_state);
+ else
+ clear_bit(R5C_LOG_TIGHT, &conf->cache_state);
+
+ if (wake_reclaim)
+ r5l_wake_reclaim(log, 0);
+}
+
+/*
+ * Put the stripe into writing-out phase by clearing STRIPE_R5C_CACHING.
+ * This function should only be called in write-back mode.
+ */
+void r5c_make_stripe_write_out(struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ struct r5l_log *log = conf->log;
+
+ BUG_ON(!r5c_is_writeback(log));
+
+ WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
+ clear_bit(STRIPE_R5C_CACHING, &sh->state);
+
+ if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+ atomic_inc(&conf->preread_active_stripes);
+}
+
+static void r5c_handle_data_cached(struct stripe_head *sh)
+{
+ int i;
+
+ for (i = sh->disks; i--; )
+ if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
+ set_bit(R5_InJournal, &sh->dev[i].flags);
+ clear_bit(R5_LOCKED, &sh->dev[i].flags);
+ }
+ clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
+}
+
+/*
+ * this journal write must contain full parity,
+ * it may also contain some data pages
+ */
+static void r5c_handle_parity_cached(struct stripe_head *sh)
+{
+ int i;
+
+ for (i = sh->disks; i--; )
+ if (test_bit(R5_InJournal, &sh->dev[i].flags))
+ set_bit(R5_Wantwrite, &sh->dev[i].flags);
+}
+
+/*
+ * Setting proper flags after writing (or flushing) data and/or parity to the
+ * log device. This is called from r5l_log_endio() or r5l_log_flush_endio().
+ */
+static void r5c_finish_cache_stripe(struct stripe_head *sh)
+{
+ struct r5l_log *log = sh->raid_conf->log;
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
+ BUG_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
+ /*
+ * Set R5_InJournal for parity dev[pd_idx]. This means
+ * all data AND parity in the journal. For RAID 6, it is
+ * NOT necessary to set the flag for dev[qd_idx], as the
+ * two parities are written out together.
+ */
+ set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
+ } else if (test_bit(STRIPE_R5C_CACHING, &sh->state)) {
+ r5c_handle_data_cached(sh);
+ } else {
+ r5c_handle_parity_cached(sh);
+ set_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
+ }
+}
+
+static void r5l_io_run_stripes(struct r5l_io_unit *io)
+{
+ struct stripe_head *sh, *next;
+
+ list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) {
+ list_del_init(&sh->log_list);
+
+ r5c_finish_cache_stripe(sh);
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+ raid5_release_stripe(sh);
+ }
+}
+
+static void r5l_log_run_stripes(struct r5l_log *log)
+{
+ struct r5l_io_unit *io, *next;
+
+ lockdep_assert_held(&log->io_list_lock);
+
+ list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) {
+ /* don't change list order */
+ if (io->state < IO_UNIT_IO_END)
+ break;
+
+ list_move_tail(&io->log_sibling, &log->finished_ios);
+ r5l_io_run_stripes(io);
+ }
+}
+
+static void r5l_move_to_end_ios(struct r5l_log *log)
+{
+ struct r5l_io_unit *io, *next;
+
+ lockdep_assert_held(&log->io_list_lock);
+
+ list_for_each_entry_safe(io, next, &log->running_ios, log_sibling) {
+ /* don't change list order */
+ if (io->state < IO_UNIT_IO_END)
+ break;
+ list_move_tail(&io->log_sibling, &log->io_end_ios);
+ }
+}
+
+static void __r5l_stripe_write_finished(struct r5l_io_unit *io);
+static void r5l_log_endio(struct bio *bio)
+{
+ struct r5l_io_unit *io = bio->bi_private;
+ struct r5l_io_unit *io_deferred;
+ struct r5l_log *log = io->log;
+ unsigned long flags;
+ bool has_null_flush;
+ bool has_flush_payload;
+
+ if (bio->bi_status)
+ md_error(log->rdev->mddev, log->rdev);
+
+ bio_put(bio);
+ mempool_free(io->meta_page, &log->meta_pool);
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_IO_END);
+
+ /*
+ * if the io doesn't not have null_flush or flush payload,
+ * it is not safe to access it after releasing io_list_lock.
+ * Therefore, it is necessary to check the condition with
+ * the lock held.
+ */
+ has_null_flush = io->has_null_flush;
+ has_flush_payload = io->has_flush_payload;
+
+ if (log->need_cache_flush && !list_empty(&io->stripe_list))
+ r5l_move_to_end_ios(log);
+ else
+ r5l_log_run_stripes(log);
+ if (!list_empty(&log->running_ios)) {
+ /*
+ * FLUSH/FUA io_unit is deferred because of ordering, now we
+ * can dispatch it
+ */
+ io_deferred = list_first_entry(&log->running_ios,
+ struct r5l_io_unit, log_sibling);
+ if (io_deferred->io_deferred)
+ schedule_work(&log->deferred_io_work);
+ }
+
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+
+ if (log->need_cache_flush)
+ md_wakeup_thread(log->rdev->mddev->thread);
+
+ /* finish flush only io_unit and PAYLOAD_FLUSH only io_unit */
+ if (has_null_flush) {
+ struct bio *bi;
+
+ WARN_ON(bio_list_empty(&io->flush_barriers));
+ while ((bi = bio_list_pop(&io->flush_barriers)) != NULL) {
+ bio_endio(bi);
+ if (atomic_dec_and_test(&io->pending_stripe)) {
+ __r5l_stripe_write_finished(io);
+ return;
+ }
+ }
+ }
+ /* decrease pending_stripe for flush payload */
+ if (has_flush_payload)
+ if (atomic_dec_and_test(&io->pending_stripe))
+ __r5l_stripe_write_finished(io);
+}
+
+static void r5l_do_submit_io(struct r5l_log *log, struct r5l_io_unit *io)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_IO_START);
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+
+ /*
+ * In case of journal device failures, submit_bio will get error
+ * and calls endio, then active stripes will continue write
+ * process. Therefore, it is not necessary to check Faulty bit
+ * of journal device here.
+ *
+ * We can't check split_bio after current_bio is submitted. If
+ * io->split_bio is null, after current_bio is submitted, current_bio
+ * might already be completed and the io_unit is freed. We submit
+ * split_bio first to avoid the issue.
+ */
+ if (io->split_bio) {
+ if (io->has_flush)
+ io->split_bio->bi_opf |= REQ_PREFLUSH;
+ if (io->has_fua)
+ io->split_bio->bi_opf |= REQ_FUA;
+ submit_bio(io->split_bio);
+ }
+
+ if (io->has_flush)
+ io->current_bio->bi_opf |= REQ_PREFLUSH;
+ if (io->has_fua)
+ io->current_bio->bi_opf |= REQ_FUA;
+ submit_bio(io->current_bio);
+}
+
+/* deferred io_unit will be dispatched here */
+static void r5l_submit_io_async(struct work_struct *work)
+{
+ struct r5l_log *log = container_of(work, struct r5l_log,
+ deferred_io_work);
+ struct r5l_io_unit *io = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ if (!list_empty(&log->running_ios)) {
+ io = list_first_entry(&log->running_ios, struct r5l_io_unit,
+ log_sibling);
+ if (!io->io_deferred)
+ io = NULL;
+ else
+ io->io_deferred = 0;
+ }
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ if (io)
+ r5l_do_submit_io(log, io);
+}
+
+static void r5c_disable_writeback_async(struct work_struct *work)
+{
+ struct r5l_log *log = container_of(work, struct r5l_log,
+ disable_writeback_work);
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ int locked = 0;
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+ return;
+ pr_info("md/raid:%s: Disabling writeback cache for degraded array.\n",
+ mdname(mddev));
+
+ /* wait superblock change before suspend */
+ wait_event(mddev->sb_wait,
+ conf->log == NULL ||
+ (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) &&
+ (locked = mddev_trylock(mddev))));
+ if (locked) {
+ mddev_suspend(mddev);
+ log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
+ mddev_resume(mddev);
+ mddev_unlock(mddev);
+ }
+}
+
+static void r5l_submit_current_io(struct r5l_log *log)
+{
+ struct r5l_io_unit *io = log->current_io;
+ struct r5l_meta_block *block;
+ unsigned long flags;
+ u32 crc;
+ bool do_submit = true;
+
+ if (!io)
+ return;
+
+ block = page_address(io->meta_page);
+ block->meta_size = cpu_to_le32(io->meta_offset);
+ crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE);
+ block->checksum = cpu_to_le32(crc);
+
+ log->current_io = NULL;
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ if (io->has_flush || io->has_fua) {
+ if (io != list_first_entry(&log->running_ios,
+ struct r5l_io_unit, log_sibling)) {
+ io->io_deferred = 1;
+ do_submit = false;
+ }
+ }
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ if (do_submit)
+ r5l_do_submit_io(log, io);
+}
+
+static struct bio *r5l_bio_alloc(struct r5l_log *log)
+{
+ struct bio *bio = bio_alloc_bioset(GFP_NOIO, BIO_MAX_PAGES, &log->bs);
+
+ bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+ bio_set_dev(bio, log->rdev->bdev);
+ bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start;
+
+ return bio;
+}
+
+static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
+{
+ log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
+
+ r5c_update_log_state(log);
+ /*
+ * If we filled up the log device start from the beginning again,
+ * which will require a new bio.
+ *
+ * Note: for this to work properly the log size needs to me a multiple
+ * of BLOCK_SECTORS.
+ */
+ if (log->log_start == 0)
+ io->need_split_bio = true;
+
+ io->log_end = log->log_start;
+}
+
+static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
+{
+ struct r5l_io_unit *io;
+ struct r5l_meta_block *block;
+
+ io = mempool_alloc(&log->io_pool, GFP_ATOMIC);
+ if (!io)
+ return NULL;
+ memset(io, 0, sizeof(*io));
+
+ io->log = log;
+ INIT_LIST_HEAD(&io->log_sibling);
+ INIT_LIST_HEAD(&io->stripe_list);
+ bio_list_init(&io->flush_barriers);
+ io->state = IO_UNIT_RUNNING;
+
+ io->meta_page = mempool_alloc(&log->meta_pool, GFP_NOIO);
+ block = page_address(io->meta_page);
+ clear_page(block);
+ block->magic = cpu_to_le32(R5LOG_MAGIC);
+ block->version = R5LOG_VERSION;
+ block->seq = cpu_to_le64(log->seq);
+ block->position = cpu_to_le64(log->log_start);
+
+ io->log_start = log->log_start;
+ io->meta_offset = sizeof(struct r5l_meta_block);
+ io->seq = log->seq++;
+
+ io->current_bio = r5l_bio_alloc(log);
+ io->current_bio->bi_end_io = r5l_log_endio;
+ io->current_bio->bi_private = io;
+ bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
+
+ r5_reserve_log_entry(log, io);
+
+ spin_lock_irq(&log->io_list_lock);
+ list_add_tail(&io->log_sibling, &log->running_ios);
+ spin_unlock_irq(&log->io_list_lock);
+
+ return io;
+}
+
+static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
+{
+ if (log->current_io &&
+ log->current_io->meta_offset + payload_size > PAGE_SIZE)
+ r5l_submit_current_io(log);
+
+ if (!log->current_io) {
+ log->current_io = r5l_new_meta(log);
+ if (!log->current_io)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
+ sector_t location,
+ u32 checksum1, u32 checksum2,
+ bool checksum2_valid)
+{
+ struct r5l_io_unit *io = log->current_io;
+ struct r5l_payload_data_parity *payload;
+
+ payload = page_address(io->meta_page) + io->meta_offset;
+ payload->header.type = cpu_to_le16(type);
+ payload->header.flags = cpu_to_le16(0);
+ payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
+ (PAGE_SHIFT - 9));
+ payload->location = cpu_to_le64(location);
+ payload->checksum[0] = cpu_to_le32(checksum1);
+ if (checksum2_valid)
+ payload->checksum[1] = cpu_to_le32(checksum2);
+
+ io->meta_offset += sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) * (1 + !!checksum2_valid);
+}
+
+static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
+{
+ struct r5l_io_unit *io = log->current_io;
+
+ if (io->need_split_bio) {
+ BUG_ON(io->split_bio);
+ io->split_bio = io->current_bio;
+ io->current_bio = r5l_bio_alloc(log);
+ bio_chain(io->current_bio, io->split_bio);
+ io->need_split_bio = false;
+ }
+
+ if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0))
+ BUG();
+
+ r5_reserve_log_entry(log, io);
+}
+
+static void r5l_append_flush_payload(struct r5l_log *log, sector_t sect)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ struct r5l_io_unit *io;
+ struct r5l_payload_flush *payload;
+ int meta_size;
+
+ /*
+ * payload_flush requires extra writes to the journal.
+ * To avoid handling the extra IO in quiesce, just skip
+ * flush_payload
+ */
+ if (conf->quiesce)
+ return;
+
+ mutex_lock(&log->io_mutex);
+ meta_size = sizeof(struct r5l_payload_flush) + sizeof(__le64);
+
+ if (r5l_get_meta(log, meta_size)) {
+ mutex_unlock(&log->io_mutex);
+ return;
+ }
+
+ /* current implementation is one stripe per flush payload */
+ io = log->current_io;
+ payload = page_address(io->meta_page) + io->meta_offset;
+ payload->header.type = cpu_to_le16(R5LOG_PAYLOAD_FLUSH);
+ payload->header.flags = cpu_to_le16(0);
+ payload->size = cpu_to_le32(sizeof(__le64));
+ payload->flush_stripes[0] = cpu_to_le64(sect);
+ io->meta_offset += meta_size;
+ /* multiple flush payloads count as one pending_stripe */
+ if (!io->has_flush_payload) {
+ io->has_flush_payload = 1;
+ atomic_inc(&io->pending_stripe);
+ }
+ mutex_unlock(&log->io_mutex);
+}
+
+static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
+ int data_pages, int parity_pages)
+{
+ int i;
+ int meta_size;
+ int ret;
+ struct r5l_io_unit *io;
+
+ meta_size =
+ ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
+ * data_pages) +
+ sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) * parity_pages;
+
+ ret = r5l_get_meta(log, meta_size);
+ if (ret)
+ return ret;
+
+ io = log->current_io;
+
+ if (test_and_clear_bit(STRIPE_R5C_PREFLUSH, &sh->state))
+ io->has_flush = 1;
+
+ for (i = 0; i < sh->disks; i++) {
+ if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
+ test_bit(R5_InJournal, &sh->dev[i].flags))
+ continue;
+ if (i == sh->pd_idx || i == sh->qd_idx)
+ continue;
+ if (test_bit(R5_WantFUA, &sh->dev[i].flags) &&
+ log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK) {
+ io->has_fua = 1;
+ /*
+ * we need to flush journal to make sure recovery can
+ * reach the data with fua flag
+ */
+ io->has_flush = 1;
+ }
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
+ raid5_compute_blocknr(sh, i, 0),
+ sh->dev[i].log_checksum, 0, false);
+ r5l_append_payload_page(log, sh->dev[i].page);
+ }
+
+ if (parity_pages == 2) {
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
+ sh->sector, sh->dev[sh->pd_idx].log_checksum,
+ sh->dev[sh->qd_idx].log_checksum, true);
+ r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
+ r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
+ } else if (parity_pages == 1) {
+ r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
+ sh->sector, sh->dev[sh->pd_idx].log_checksum,
+ 0, false);
+ r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
+ } else /* Just writing data, not parity, in caching phase */
+ BUG_ON(parity_pages != 0);
+
+ list_add_tail(&sh->log_list, &io->stripe_list);
+ atomic_inc(&io->pending_stripe);
+ sh->log_io = io;
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+ return 0;
+
+ if (sh->log_start == MaxSector) {
+ BUG_ON(!list_empty(&sh->r5c));
+ sh->log_start = io->log_start;
+ spin_lock_irq(&log->stripe_in_journal_lock);
+ list_add_tail(&sh->r5c,
+ &log->stripe_in_journal_list);
+ spin_unlock_irq(&log->stripe_in_journal_lock);
+ atomic_inc(&log->stripe_in_journal_count);
+ }
+ return 0;
+}
+
+/* add stripe to no_space_stripes, and then wake up reclaim */
+static inline void r5l_add_no_space_stripe(struct r5l_log *log,
+ struct stripe_head *sh)
+{
+ spin_lock(&log->no_space_stripes_lock);
+ list_add_tail(&sh->log_list, &log->no_space_stripes);
+ spin_unlock(&log->no_space_stripes_lock);
+}
+
+/*
+ * running in raid5d, where reclaim could wait for raid5d too (when it flushes
+ * data from log to raid disks), so we shouldn't wait for reclaim here
+ */
+int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int write_disks = 0;
+ int data_pages, parity_pages;
+ int reserve;
+ int i;
+ int ret = 0;
+ bool wake_reclaim = false;
+
+ if (!log)
+ return -EAGAIN;
+ /* Don't support stripe batch */
+ if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
+ test_bit(STRIPE_SYNCING, &sh->state)) {
+ /* the stripe is written to log, we start writing it to raid */
+ clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
+ return -EAGAIN;
+ }
+
+ WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
+
+ for (i = 0; i < sh->disks; i++) {
+ void *addr;
+
+ if (!test_bit(R5_Wantwrite, &sh->dev[i].flags) ||
+ test_bit(R5_InJournal, &sh->dev[i].flags))
+ continue;
+
+ write_disks++;
+ /* checksum is already calculated in last run */
+ if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
+ continue;
+ addr = kmap_atomic(sh->dev[i].page);
+ sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
+ addr, PAGE_SIZE);
+ kunmap_atomic(addr);
+ }
+ parity_pages = 1 + !!(sh->qd_idx >= 0);
+ data_pages = write_disks - parity_pages;
+
+ set_bit(STRIPE_LOG_TRAPPED, &sh->state);
+ /*
+ * The stripe must enter state machine again to finish the write, so
+ * don't delay.
+ */
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ atomic_inc(&sh->count);
+
+ mutex_lock(&log->io_mutex);
+ /* meta + data */
+ reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
+ if (!r5l_has_free_space(log, reserve)) {
+ r5l_add_no_space_stripe(log, sh);
+ wake_reclaim = true;
+ } else {
+ ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
+ if (ret) {
+ spin_lock_irq(&log->io_list_lock);
+ list_add_tail(&sh->log_list,
+ &log->no_mem_stripes);
+ spin_unlock_irq(&log->io_list_lock);
+ }
+ }
+ } else { /* R5C_JOURNAL_MODE_WRITE_BACK */
+ /*
+ * log space critical, do not process stripes that are
+ * not in cache yet (sh->log_start == MaxSector).
+ */
+ if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
+ sh->log_start == MaxSector) {
+ r5l_add_no_space_stripe(log, sh);
+ wake_reclaim = true;
+ reserve = 0;
+ } else if (!r5l_has_free_space(log, reserve)) {
+ if (sh->log_start == log->last_checkpoint)
+ BUG();
+ else
+ r5l_add_no_space_stripe(log, sh);
+ } else {
+ ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
+ if (ret) {
+ spin_lock_irq(&log->io_list_lock);
+ list_add_tail(&sh->log_list,
+ &log->no_mem_stripes);
+ spin_unlock_irq(&log->io_list_lock);
+ }
+ }
+ }
+
+ mutex_unlock(&log->io_mutex);
+ if (wake_reclaim)
+ r5l_wake_reclaim(log, reserve);
+ return 0;
+}
+
+void r5l_write_stripe_run(struct r5l_log *log)
+{
+ if (!log)
+ return;
+ mutex_lock(&log->io_mutex);
+ r5l_submit_current_io(log);
+ mutex_unlock(&log->io_mutex);
+}
+
+int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio)
+{
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
+ /*
+ * in write through (journal only)
+ * we flush log disk cache first, then write stripe data to
+ * raid disks. So if bio is finished, the log disk cache is
+ * flushed already. The recovery guarantees we can recovery
+ * the bio from log disk, so we don't need to flush again
+ */
+ if (bio->bi_iter.bi_size == 0) {
+ bio_endio(bio);
+ return 0;
+ }
+ bio->bi_opf &= ~REQ_PREFLUSH;
+ } else {
+ /* write back (with cache) */
+ if (bio->bi_iter.bi_size == 0) {
+ mutex_lock(&log->io_mutex);
+ r5l_get_meta(log, 0);
+ bio_list_add(&log->current_io->flush_barriers, bio);
+ log->current_io->has_flush = 1;
+ log->current_io->has_null_flush = 1;
+ atomic_inc(&log->current_io->pending_stripe);
+ r5l_submit_current_io(log);
+ mutex_unlock(&log->io_mutex);
+ return 0;
+ }
+ }
+ return -EAGAIN;
+}
+
+/* This will run after log space is reclaimed */
+static void r5l_run_no_space_stripes(struct r5l_log *log)
+{
+ struct stripe_head *sh;
+
+ spin_lock(&log->no_space_stripes_lock);
+ while (!list_empty(&log->no_space_stripes)) {
+ sh = list_first_entry(&log->no_space_stripes,
+ struct stripe_head, log_list);
+ list_del_init(&sh->log_list);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ raid5_release_stripe(sh);
+ }
+ spin_unlock(&log->no_space_stripes_lock);
+}
+
+/*
+ * calculate new last_checkpoint
+ * for write through mode, returns log->next_checkpoint
+ * for write back, returns log_start of first sh in stripe_in_journal_list
+ */
+static sector_t r5c_calculate_new_cp(struct r5conf *conf)
+{
+ struct stripe_head *sh;
+ struct r5l_log *log = conf->log;
+ sector_t new_cp;
+ unsigned long flags;
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+ return log->next_checkpoint;
+
+ spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
+ if (list_empty(&conf->log->stripe_in_journal_list)) {
+ /* all stripes flushed */
+ spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
+ return log->next_checkpoint;
+ }
+ sh = list_first_entry(&conf->log->stripe_in_journal_list,
+ struct stripe_head, r5c);
+ new_cp = sh->log_start;
+ spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
+ return new_cp;
+}
+
+static sector_t r5l_reclaimable_space(struct r5l_log *log)
+{
+ struct r5conf *conf = log->rdev->mddev->private;
+
+ return r5l_ring_distance(log, log->last_checkpoint,
+ r5c_calculate_new_cp(conf));
+}
+
+static void r5l_run_no_mem_stripe(struct r5l_log *log)
+{
+ struct stripe_head *sh;
+
+ lockdep_assert_held(&log->io_list_lock);
+
+ if (!list_empty(&log->no_mem_stripes)) {
+ sh = list_first_entry(&log->no_mem_stripes,
+ struct stripe_head, log_list);
+ list_del_init(&sh->log_list);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ raid5_release_stripe(sh);
+ }
+}
+
+static bool r5l_complete_finished_ios(struct r5l_log *log)
+{
+ struct r5l_io_unit *io, *next;
+ bool found = false;
+
+ lockdep_assert_held(&log->io_list_lock);
+
+ list_for_each_entry_safe(io, next, &log->finished_ios, log_sibling) {
+ /* don't change list order */
+ if (io->state < IO_UNIT_STRIPE_END)
+ break;
+
+ log->next_checkpoint = io->log_start;
+
+ list_del(&io->log_sibling);
+ mempool_free(io, &log->io_pool);
+ r5l_run_no_mem_stripe(log);
+
+ found = true;
+ }
+
+ return found;
+}
+
+static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
+{
+ struct r5l_log *log = io->log;
+ struct r5conf *conf = log->rdev->mddev->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ __r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
+
+ if (!r5l_complete_finished_ios(log)) {
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ return;
+ }
+
+ if (r5l_reclaimable_space(log) > log->max_free_space ||
+ test_bit(R5C_LOG_TIGHT, &conf->cache_state))
+ r5l_wake_reclaim(log, 0);
+
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+ wake_up(&log->iounit_wait);
+}
+
+void r5l_stripe_write_finished(struct stripe_head *sh)
+{
+ struct r5l_io_unit *io;
+
+ io = sh->log_io;
+ sh->log_io = NULL;
+
+ if (io && atomic_dec_and_test(&io->pending_stripe))
+ __r5l_stripe_write_finished(io);
+}
+
+static void r5l_log_flush_endio(struct bio *bio)
+{
+ struct r5l_log *log = container_of(bio, struct r5l_log,
+ flush_bio);
+ unsigned long flags;
+ struct r5l_io_unit *io;
+
+ if (bio->bi_status)
+ md_error(log->rdev->mddev, log->rdev);
+
+ spin_lock_irqsave(&log->io_list_lock, flags);
+ list_for_each_entry(io, &log->flushing_ios, log_sibling)
+ r5l_io_run_stripes(io);
+ list_splice_tail_init(&log->flushing_ios, &log->finished_ios);
+ spin_unlock_irqrestore(&log->io_list_lock, flags);
+}
+
+/*
+ * Starting dispatch IO to raid.
+ * io_unit(meta) consists of a log. There is one situation we want to avoid. A
+ * broken meta in the middle of a log causes recovery can't find meta at the
+ * head of log. If operations require meta at the head persistent in log, we
+ * must make sure meta before it persistent in log too. A case is:
+ *
+ * stripe data/parity is in log, we start write stripe to raid disks. stripe
+ * data/parity must be persistent in log before we do the write to raid disks.
+ *
+ * The solution is we restrictly maintain io_unit list order. In this case, we
+ * only write stripes of an io_unit to raid disks till the io_unit is the first
+ * one whose data/parity is in log.
+ */
+void r5l_flush_stripe_to_raid(struct r5l_log *log)
+{
+ bool do_flush;
+
+ if (!log || !log->need_cache_flush)
+ return;
+
+ spin_lock_irq(&log->io_list_lock);
+ /* flush bio is running */
+ if (!list_empty(&log->flushing_ios)) {
+ spin_unlock_irq(&log->io_list_lock);
+ return;
+ }
+ list_splice_tail_init(&log->io_end_ios, &log->flushing_ios);
+ do_flush = !list_empty(&log->flushing_ios);
+ spin_unlock_irq(&log->io_list_lock);
+
+ if (!do_flush)
+ return;
+ bio_reset(&log->flush_bio);
+ bio_set_dev(&log->flush_bio, log->rdev->bdev);
+ log->flush_bio.bi_end_io = r5l_log_flush_endio;
+ log->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
+ submit_bio(&log->flush_bio);
+}
+
+static void r5l_write_super(struct r5l_log *log, sector_t cp);
+static void r5l_write_super_and_discard_space(struct r5l_log *log,
+ sector_t end)
+{
+ struct block_device *bdev = log->rdev->bdev;
+ struct mddev *mddev;
+
+ r5l_write_super(log, end);
+
+ if (!blk_queue_discard(bdev_get_queue(bdev)))
+ return;
+
+ mddev = log->rdev->mddev;
+ /*
+ * Discard could zero data, so before discard we must make sure
+ * superblock is updated to new log tail. Updating superblock (either
+ * directly call md_update_sb() or depend on md thread) must hold
+ * reconfig mutex. On the other hand, raid5_quiesce is called with
+ * reconfig_mutex hold. The first step of raid5_quiesce() is waitting
+ * for all IO finish, hence waitting for reclaim thread, while reclaim
+ * thread is calling this function and waitting for reconfig mutex. So
+ * there is a deadlock. We workaround this issue with a trylock.
+ * FIXME: we could miss discard if we can't take reconfig mutex
+ */
+ set_mask_bits(&mddev->sb_flags, 0,
+ BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
+ if (!mddev_trylock(mddev))
+ return;
+ md_update_sb(mddev, 1);
+ mddev_unlock(mddev);
+
+ /* discard IO error really doesn't matter, ignore it */
+ if (log->last_checkpoint < end) {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ end - log->last_checkpoint, GFP_NOIO, 0);
+ } else {
+ blkdev_issue_discard(bdev,
+ log->last_checkpoint + log->rdev->data_offset,
+ log->device_size - log->last_checkpoint,
+ GFP_NOIO, 0);
+ blkdev_issue_discard(bdev, log->rdev->data_offset, end,
+ GFP_NOIO, 0);
+ }
+}
+
+/*
+ * r5c_flush_stripe moves stripe from cached list to handle_list. When called,
+ * the stripe must be on r5c_cached_full_stripes or r5c_cached_partial_stripes.
+ *
+ * must hold conf->device_lock
+ */
+static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh)
+{
+ BUG_ON(list_empty(&sh->lru));
+ BUG_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
+ BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
+
+ /*
+ * The stripe is not ON_RELEASE_LIST, so it is safe to call
+ * raid5_release_stripe() while holding conf->device_lock
+ */
+ BUG_ON(test_bit(STRIPE_ON_RELEASE_LIST, &sh->state));
+ lockdep_assert_held(&conf->device_lock);
+
+ list_del_init(&sh->lru);
+ atomic_inc(&sh->count);
+
+ set_bit(STRIPE_HANDLE, &sh->state);
+ atomic_inc(&conf->active_stripes);
+ r5c_make_stripe_write_out(sh);
+
+ if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
+ atomic_inc(&conf->r5c_flushing_partial_stripes);
+ else
+ atomic_inc(&conf->r5c_flushing_full_stripes);
+ raid5_release_stripe(sh);
+}
+
+/*
+ * if num == 0, flush all full stripes
+ * if num > 0, flush all full stripes. If less than num full stripes are
+ * flushed, flush some partial stripes until totally num stripes are
+ * flushed or there is no more cached stripes.
+ */
+void r5c_flush_cache(struct r5conf *conf, int num)
+{
+ int count;
+ struct stripe_head *sh, *next;
+
+ lockdep_assert_held(&conf->device_lock);
+ if (!conf->log)
+ return;
+
+ count = 0;
+ list_for_each_entry_safe(sh, next, &conf->r5c_full_stripe_list, lru) {
+ r5c_flush_stripe(conf, sh);
+ count++;
+ }
+
+ if (count >= num)
+ return;
+ list_for_each_entry_safe(sh, next,
+ &conf->r5c_partial_stripe_list, lru) {
+ r5c_flush_stripe(conf, sh);
+ if (++count >= num)
+ break;
+ }
+}
+
+static void r5c_do_reclaim(struct r5conf *conf)
+{
+ struct r5l_log *log = conf->log;
+ struct stripe_head *sh;
+ int count = 0;
+ unsigned long flags;
+ int total_cached;
+ int stripes_to_flush;
+ int flushing_partial, flushing_full;
+
+ if (!r5c_is_writeback(log))
+ return;
+
+ flushing_partial = atomic_read(&conf->r5c_flushing_partial_stripes);
+ flushing_full = atomic_read(&conf->r5c_flushing_full_stripes);
+ total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
+ atomic_read(&conf->r5c_cached_full_stripes) -
+ flushing_full - flushing_partial;
+
+ if (total_cached > conf->min_nr_stripes * 3 / 4 ||
+ atomic_read(&conf->empty_inactive_list_nr) > 0)
+ /*
+ * if stripe cache pressure high, flush all full stripes and
+ * some partial stripes
+ */
+ stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP;
+ else if (total_cached > conf->min_nr_stripes * 1 / 2 ||
+ atomic_read(&conf->r5c_cached_full_stripes) - flushing_full >
+ R5C_FULL_STRIPE_FLUSH_BATCH(conf))
+ /*
+ * if stripe cache pressure moderate, or if there is many full
+ * stripes,flush all full stripes
+ */
+ stripes_to_flush = 0;
+ else
+ /* no need to flush */
+ stripes_to_flush = -1;
+
+ if (stripes_to_flush >= 0) {
+ spin_lock_irqsave(&conf->device_lock, flags);
+ r5c_flush_cache(conf, stripes_to_flush);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
+ }
+
+ /* if log space is tight, flush stripes on stripe_in_journal_list */
+ if (test_bit(R5C_LOG_TIGHT, &conf->cache_state)) {
+ spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
+ spin_lock(&conf->device_lock);
+ list_for_each_entry(sh, &log->stripe_in_journal_list, r5c) {
+ /*
+ * stripes on stripe_in_journal_list could be in any
+ * state of the stripe_cache state machine. In this
+ * case, we only want to flush stripe on
+ * r5c_cached_full/partial_stripes. The following
+ * condition makes sure the stripe is on one of the
+ * two lists.
+ */
+ if (!list_empty(&sh->lru) &&
+ !test_bit(STRIPE_HANDLE, &sh->state) &&
+ atomic_read(&sh->count) == 0) {
+ r5c_flush_stripe(conf, sh);
+ if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
+ break;
+ }
+ }
+ spin_unlock(&conf->device_lock);
+ spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
+ }
+
+ if (!test_bit(R5C_LOG_CRITICAL, &conf->cache_state))
+ r5l_run_no_space_stripes(log);
+
+ md_wakeup_thread(conf->mddev->thread);
+}
+
+static void r5l_do_reclaim(struct r5l_log *log)
+{
+ struct r5conf *conf = log->rdev->mddev->private;
+ sector_t reclaim_target = xchg(&log->reclaim_target, 0);
+ sector_t reclaimable;
+ sector_t next_checkpoint;
+ bool write_super;
+
+ spin_lock_irq(&log->io_list_lock);
+ write_super = r5l_reclaimable_space(log) > log->max_free_space ||
+ reclaim_target != 0 || !list_empty(&log->no_space_stripes);
+ /*
+ * move proper io_unit to reclaim list. We should not change the order.
+ * reclaimable/unreclaimable io_unit can be mixed in the list, we
+ * shouldn't reuse space of an unreclaimable io_unit
+ */
+ while (1) {
+ reclaimable = r5l_reclaimable_space(log);
+ if (reclaimable >= reclaim_target ||
+ (list_empty(&log->running_ios) &&
+ list_empty(&log->io_end_ios) &&
+ list_empty(&log->flushing_ios) &&
+ list_empty(&log->finished_ios)))
+ break;
+
+ md_wakeup_thread(log->rdev->mddev->thread);
+ wait_event_lock_irq(log->iounit_wait,
+ r5l_reclaimable_space(log) > reclaimable,
+ log->io_list_lock);
+ }
+
+ next_checkpoint = r5c_calculate_new_cp(conf);
+ spin_unlock_irq(&log->io_list_lock);
+
+ if (reclaimable == 0 || !write_super)
+ return;
+
+ /*
+ * write_super will flush cache of each raid disk. We must write super
+ * here, because the log area might be reused soon and we don't want to
+ * confuse recovery
+ */
+ r5l_write_super_and_discard_space(log, next_checkpoint);
+
+ mutex_lock(&log->io_mutex);
+ log->last_checkpoint = next_checkpoint;
+ r5c_update_log_state(log);
+ mutex_unlock(&log->io_mutex);
+
+ r5l_run_no_space_stripes(log);
+}
+
+static void r5l_reclaim_thread(struct md_thread *thread)
+{
+ struct mddev *mddev = thread->mddev;
+ struct r5conf *conf = mddev->private;
+ struct r5l_log *log = conf->log;
+
+ if (!log)
+ return;
+ r5c_do_reclaim(conf);
+ r5l_do_reclaim(log);
+}
+
+void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
+{
+ unsigned long target;
+ unsigned long new = (unsigned long)space; /* overflow in theory */
+
+ if (!log)
+ return;
+ do {
+ target = log->reclaim_target;
+ if (new < target)
+ return;
+ } while (cmpxchg(&log->reclaim_target, target, new) != target);
+ md_wakeup_thread(log->reclaim_thread);
+}
+
+void r5l_quiesce(struct r5l_log *log, int quiesce)
+{
+ struct mddev *mddev;
+
+ if (quiesce) {
+ /* make sure r5l_write_super_and_discard_space exits */
+ mddev = log->rdev->mddev;
+ wake_up(&mddev->sb_wait);
+ kthread_park(log->reclaim_thread->tsk);
+ r5l_wake_reclaim(log, MaxSector);
+ r5l_do_reclaim(log);
+ } else
+ kthread_unpark(log->reclaim_thread->tsk);
+}
+
+bool r5l_log_disk_error(struct r5conf *conf)
+{
+ struct r5l_log *log;
+ bool ret;
+ /* don't allow write if journal disk is missing */
+ rcu_read_lock();
+ log = rcu_dereference(conf->log);
+
+ if (!log)
+ ret = test_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
+ else
+ ret = test_bit(Faulty, &log->rdev->flags);
+ rcu_read_unlock();
+ return ret;
+}
+
+#define R5L_RECOVERY_PAGE_POOL_SIZE 256
+
+struct r5l_recovery_ctx {
+ struct page *meta_page; /* current meta */
+ sector_t meta_total_blocks; /* total size of current meta and data */
+ sector_t pos; /* recovery position */
+ u64 seq; /* recovery position seq */
+ int data_parity_stripes; /* number of data_parity stripes */
+ int data_only_stripes; /* number of data_only stripes */
+ struct list_head cached_list;
+
+ /*
+ * read ahead page pool (ra_pool)
+ * in recovery, log is read sequentially. It is not efficient to
+ * read every page with sync_page_io(). The read ahead page pool
+ * reads multiple pages with one IO, so further log read can
+ * just copy data from the pool.
+ */
+ struct page *ra_pool[R5L_RECOVERY_PAGE_POOL_SIZE];
+ sector_t pool_offset; /* offset of first page in the pool */
+ int total_pages; /* total allocated pages */
+ int valid_pages; /* pages with valid data */
+ struct bio *ra_bio; /* bio to do the read ahead */
+};
+
+static int r5l_recovery_allocate_ra_pool(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct page *page;
+
+ ctx->ra_bio = bio_alloc_bioset(GFP_KERNEL, BIO_MAX_PAGES, &log->bs);
+ if (!ctx->ra_bio)
+ return -ENOMEM;
+
+ ctx->valid_pages = 0;
+ ctx->total_pages = 0;
+ while (ctx->total_pages < R5L_RECOVERY_PAGE_POOL_SIZE) {
+ page = alloc_page(GFP_KERNEL);
+
+ if (!page)
+ break;
+ ctx->ra_pool[ctx->total_pages] = page;
+ ctx->total_pages += 1;
+ }
+
+ if (ctx->total_pages == 0) {
+ bio_put(ctx->ra_bio);
+ return -ENOMEM;
+ }
+
+ ctx->pool_offset = 0;
+ return 0;
+}
+
+static void r5l_recovery_free_ra_pool(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ int i;
+
+ for (i = 0; i < ctx->total_pages; ++i)
+ put_page(ctx->ra_pool[i]);
+ bio_put(ctx->ra_bio);
+}
+
+/*
+ * fetch ctx->valid_pages pages from offset
+ * In normal cases, ctx->valid_pages == ctx->total_pages after the call.
+ * However, if the offset is close to the end of the journal device,
+ * ctx->valid_pages could be smaller than ctx->total_pages
+ */
+static int r5l_recovery_fetch_ra_pool(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx,
+ sector_t offset)
+{
+ bio_reset(ctx->ra_bio);
+ bio_set_dev(ctx->ra_bio, log->rdev->bdev);
+ bio_set_op_attrs(ctx->ra_bio, REQ_OP_READ, 0);
+ ctx->ra_bio->bi_iter.bi_sector = log->rdev->data_offset + offset;
+
+ ctx->valid_pages = 0;
+ ctx->pool_offset = offset;
+
+ while (ctx->valid_pages < ctx->total_pages) {
+ bio_add_page(ctx->ra_bio,
+ ctx->ra_pool[ctx->valid_pages], PAGE_SIZE, 0);
+ ctx->valid_pages += 1;
+
+ offset = r5l_ring_add(log, offset, BLOCK_SECTORS);
+
+ if (offset == 0) /* reached end of the device */
+ break;
+ }
+
+ return submit_bio_wait(ctx->ra_bio);
+}
+
+/*
+ * try read a page from the read ahead page pool, if the page is not in the
+ * pool, call r5l_recovery_fetch_ra_pool
+ */
+static int r5l_recovery_read_page(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx,
+ struct page *page,
+ sector_t offset)
+{
+ int ret;
+
+ if (offset < ctx->pool_offset ||
+ offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS) {
+ ret = r5l_recovery_fetch_ra_pool(log, ctx, offset);
+ if (ret)
+ return ret;
+ }
+
+ BUG_ON(offset < ctx->pool_offset ||
+ offset >= ctx->pool_offset + ctx->valid_pages * BLOCK_SECTORS);
+
+ memcpy(page_address(page),
+ page_address(ctx->ra_pool[(offset - ctx->pool_offset) >>
+ BLOCK_SECTOR_SHIFT]),
+ PAGE_SIZE);
+ return 0;
+}
+
+static int r5l_recovery_read_meta_block(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct page *page = ctx->meta_page;
+ struct r5l_meta_block *mb;
+ u32 crc, stored_crc;
+ int ret;
+
+ ret = r5l_recovery_read_page(log, ctx, page, ctx->pos);
+ if (ret != 0)
+ return ret;
+
+ mb = page_address(page);
+ stored_crc = le32_to_cpu(mb->checksum);
+ mb->checksum = 0;
+
+ if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
+ le64_to_cpu(mb->seq) != ctx->seq ||
+ mb->version != R5LOG_VERSION ||
+ le64_to_cpu(mb->position) != ctx->pos)
+ return -EINVAL;
+
+ crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+ if (stored_crc != crc)
+ return -EINVAL;
+
+ if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
+ return -EINVAL;
+
+ ctx->meta_total_blocks = BLOCK_SECTORS;
+
+ return 0;
+}
+
+static void
+r5l_recovery_create_empty_meta_block(struct r5l_log *log,
+ struct page *page,
+ sector_t pos, u64 seq)
+{
+ struct r5l_meta_block *mb;
+
+ mb = page_address(page);
+ clear_page(mb);
+ mb->magic = cpu_to_le32(R5LOG_MAGIC);
+ mb->version = R5LOG_VERSION;
+ mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
+ mb->seq = cpu_to_le64(seq);
+ mb->position = cpu_to_le64(pos);
+}
+
+static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
+ u64 seq)
+{
+ struct page *page;
+ struct r5l_meta_block *mb;
+
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+ r5l_recovery_create_empty_meta_block(log, page, pos, seq);
+ mb = page_address(page);
+ mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
+ mb, PAGE_SIZE));
+ if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE,
+ REQ_SYNC | REQ_FUA, false)) {
+ __free_page(page);
+ return -EIO;
+ }
+ __free_page(page);
+ return 0;
+}
+
+/*
+ * r5l_recovery_load_data and r5l_recovery_load_parity uses flag R5_Wantwrite
+ * to mark valid (potentially not flushed) data in the journal.
+ *
+ * We already verified checksum in r5l_recovery_verify_data_checksum_for_mb,
+ * so there should not be any mismatch here.
+ */
+static void r5l_recovery_load_data(struct r5l_log *log,
+ struct stripe_head *sh,
+ struct r5l_recovery_ctx *ctx,
+ struct r5l_payload_data_parity *payload,
+ sector_t log_offset)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ int dd_idx;
+
+ raid5_compute_sector(conf,
+ le64_to_cpu(payload->location), 0,
+ &dd_idx, sh);
+ r5l_recovery_read_page(log, ctx, sh->dev[dd_idx].page, log_offset);
+ sh->dev[dd_idx].log_checksum =
+ le32_to_cpu(payload->checksum[0]);
+ ctx->meta_total_blocks += BLOCK_SECTORS;
+
+ set_bit(R5_Wantwrite, &sh->dev[dd_idx].flags);
+ set_bit(STRIPE_R5C_CACHING, &sh->state);
+}
+
+static void r5l_recovery_load_parity(struct r5l_log *log,
+ struct stripe_head *sh,
+ struct r5l_recovery_ctx *ctx,
+ struct r5l_payload_data_parity *payload,
+ sector_t log_offset)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+
+ ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded;
+ r5l_recovery_read_page(log, ctx, sh->dev[sh->pd_idx].page, log_offset);
+ sh->dev[sh->pd_idx].log_checksum =
+ le32_to_cpu(payload->checksum[0]);
+ set_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags);
+
+ if (sh->qd_idx >= 0) {
+ r5l_recovery_read_page(
+ log, ctx, sh->dev[sh->qd_idx].page,
+ r5l_ring_add(log, log_offset, BLOCK_SECTORS));
+ sh->dev[sh->qd_idx].log_checksum =
+ le32_to_cpu(payload->checksum[1]);
+ set_bit(R5_Wantwrite, &sh->dev[sh->qd_idx].flags);
+ }
+ clear_bit(STRIPE_R5C_CACHING, &sh->state);
+}
+
+static void r5l_recovery_reset_stripe(struct stripe_head *sh)
+{
+ int i;
+
+ sh->state = 0;
+ sh->log_start = MaxSector;
+ for (i = sh->disks; i--; )
+ sh->dev[i].flags = 0;
+}
+
+static void
+r5l_recovery_replay_one_stripe(struct r5conf *conf,
+ struct stripe_head *sh,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct md_rdev *rdev, *rrdev;
+ int disk_index;
+ int data_count = 0;
+
+ for (disk_index = 0; disk_index < sh->disks; disk_index++) {
+ if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
+ continue;
+ if (disk_index == sh->qd_idx || disk_index == sh->pd_idx)
+ continue;
+ data_count++;
+ }
+
+ /*
+ * stripes that only have parity must have been flushed
+ * before the crash that we are now recovering from, so
+ * there is nothing more to recovery.
+ */
+ if (data_count == 0)
+ goto out;
+
+ for (disk_index = 0; disk_index < sh->disks; disk_index++) {
+ if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
+ continue;
+
+ /* in case device is broken */
+ rcu_read_lock();
+ rdev = rcu_dereference(conf->disks[disk_index].rdev);
+ if (rdev) {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ sync_page_io(rdev, sh->sector, PAGE_SIZE,
+ sh->dev[disk_index].page, REQ_OP_WRITE, 0,
+ false);
+ rdev_dec_pending(rdev, rdev->mddev);
+ rcu_read_lock();
+ }
+ rrdev = rcu_dereference(conf->disks[disk_index].replacement);
+ if (rrdev) {
+ atomic_inc(&rrdev->nr_pending);
+ rcu_read_unlock();
+ sync_page_io(rrdev, sh->sector, PAGE_SIZE,
+ sh->dev[disk_index].page, REQ_OP_WRITE, 0,
+ false);
+ rdev_dec_pending(rrdev, rrdev->mddev);
+ rcu_read_lock();
+ }
+ rcu_read_unlock();
+ }
+ ctx->data_parity_stripes++;
+out:
+ r5l_recovery_reset_stripe(sh);
+}
+
+static struct stripe_head *
+r5c_recovery_alloc_stripe(struct r5conf *conf,
+ sector_t stripe_sect)
+{
+ struct stripe_head *sh;
+
+ sh = raid5_get_active_stripe(conf, stripe_sect, 0, 1, 0);
+ if (!sh)
+ return NULL; /* no more stripe available */
+
+ r5l_recovery_reset_stripe(sh);
+
+ return sh;
+}
+
+static struct stripe_head *
+r5c_recovery_lookup_stripe(struct list_head *list, sector_t sect)
+{
+ struct stripe_head *sh;
+
+ list_for_each_entry(sh, list, lru)
+ if (sh->sector == sect)
+ return sh;
+ return NULL;
+}
+
+static void
+r5c_recovery_drop_stripes(struct list_head *cached_stripe_list,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct stripe_head *sh, *next;
+
+ list_for_each_entry_safe(sh, next, cached_stripe_list, lru) {
+ r5l_recovery_reset_stripe(sh);
+ list_del_init(&sh->lru);
+ raid5_release_stripe(sh);
+ }
+}
+
+static void
+r5c_recovery_replay_stripes(struct list_head *cached_stripe_list,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct stripe_head *sh, *next;
+
+ list_for_each_entry_safe(sh, next, cached_stripe_list, lru)
+ if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
+ r5l_recovery_replay_one_stripe(sh->raid_conf, sh, ctx);
+ list_del_init(&sh->lru);
+ raid5_release_stripe(sh);
+ }
+}
+
+/* if matches return 0; otherwise return -EINVAL */
+static int
+r5l_recovery_verify_data_checksum(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx,
+ struct page *page,
+ sector_t log_offset, __le32 log_checksum)
+{
+ void *addr;
+ u32 checksum;
+
+ r5l_recovery_read_page(log, ctx, page, log_offset);
+ addr = kmap_atomic(page);
+ checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);
+ kunmap_atomic(addr);
+ return (le32_to_cpu(log_checksum) == checksum) ? 0 : -EINVAL;
+}
+
+/*
+ * before loading data to stripe cache, we need verify checksum for all data,
+ * if there is mismatch for any data page, we drop all data in the mata block
+ */
+static int
+r5l_recovery_verify_data_checksum_for_mb(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ struct r5l_meta_block *mb = page_address(ctx->meta_page);
+ sector_t mb_offset = sizeof(struct r5l_meta_block);
+ sector_t log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+ struct page *page;
+ struct r5l_payload_data_parity *payload;
+ struct r5l_payload_flush *payload_flush;
+
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+
+ while (mb_offset < le32_to_cpu(mb->meta_size)) {
+ payload = (void *)mb + mb_offset;
+ payload_flush = (void *)mb + mb_offset;
+
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
+ if (r5l_recovery_verify_data_checksum(
+ log, ctx, page, log_offset,
+ payload->checksum[0]) < 0)
+ goto mismatch;
+ } else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY) {
+ if (r5l_recovery_verify_data_checksum(
+ log, ctx, page, log_offset,
+ payload->checksum[0]) < 0)
+ goto mismatch;
+ if (conf->max_degraded == 2 && /* q for RAID 6 */
+ r5l_recovery_verify_data_checksum(
+ log, ctx, page,
+ r5l_ring_add(log, log_offset,
+ BLOCK_SECTORS),
+ payload->checksum[1]) < 0)
+ goto mismatch;
+ } else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
+ /* nothing to do for R5LOG_PAYLOAD_FLUSH here */
+ } else /* not R5LOG_PAYLOAD_DATA/PARITY/FLUSH */
+ goto mismatch;
+
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
+ mb_offset += sizeof(struct r5l_payload_flush) +
+ le32_to_cpu(payload_flush->size);
+ } else {
+ /* DATA or PARITY payload */
+ log_offset = r5l_ring_add(log, log_offset,
+ le32_to_cpu(payload->size));
+ mb_offset += sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) *
+ (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
+ }
+
+ }
+
+ put_page(page);
+ return 0;
+
+mismatch:
+ put_page(page);
+ return -EINVAL;
+}
+
+/*
+ * Analyze all data/parity pages in one meta block
+ * Returns:
+ * 0 for success
+ * -EINVAL for unknown playload type
+ * -EAGAIN for checksum mismatch of data page
+ * -ENOMEM for run out of memory (alloc_page failed or run out of stripes)
+ */
+static int
+r5c_recovery_analyze_meta_block(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx,
+ struct list_head *cached_stripe_list)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ struct r5l_meta_block *mb;
+ struct r5l_payload_data_parity *payload;
+ struct r5l_payload_flush *payload_flush;
+ int mb_offset;
+ sector_t log_offset;
+ sector_t stripe_sect;
+ struct stripe_head *sh;
+ int ret;
+
+ /*
+ * for mismatch in data blocks, we will drop all data in this mb, but
+ * we will still read next mb for other data with FLUSH flag, as
+ * io_unit could finish out of order.
+ */
+ ret = r5l_recovery_verify_data_checksum_for_mb(log, ctx);
+ if (ret == -EINVAL)
+ return -EAGAIN;
+ else if (ret)
+ return ret; /* -ENOMEM duo to alloc_page() failed */
+
+ mb = page_address(ctx->meta_page);
+ mb_offset = sizeof(struct r5l_meta_block);
+ log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+
+ while (mb_offset < le32_to_cpu(mb->meta_size)) {
+ int dd;
+
+ payload = (void *)mb + mb_offset;
+ payload_flush = (void *)mb + mb_offset;
+
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_FLUSH) {
+ int i, count;
+
+ count = le32_to_cpu(payload_flush->size) / sizeof(__le64);
+ for (i = 0; i < count; ++i) {
+ stripe_sect = le64_to_cpu(payload_flush->flush_stripes[i]);
+ sh = r5c_recovery_lookup_stripe(cached_stripe_list,
+ stripe_sect);
+ if (sh) {
+ WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
+ r5l_recovery_reset_stripe(sh);
+ list_del_init(&sh->lru);
+ raid5_release_stripe(sh);
+ }
+ }
+
+ mb_offset += sizeof(struct r5l_payload_flush) +
+ le32_to_cpu(payload_flush->size);
+ continue;
+ }
+
+ /* DATA or PARITY payload */
+ stripe_sect = (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) ?
+ raid5_compute_sector(
+ conf, le64_to_cpu(payload->location), 0, &dd,
+ NULL)
+ : le64_to_cpu(payload->location);
+
+ sh = r5c_recovery_lookup_stripe(cached_stripe_list,
+ stripe_sect);
+
+ if (!sh) {
+ sh = r5c_recovery_alloc_stripe(conf, stripe_sect);
+ /*
+ * cannot get stripe from raid5_get_active_stripe
+ * try replay some stripes
+ */
+ if (!sh) {
+ r5c_recovery_replay_stripes(
+ cached_stripe_list, ctx);
+ sh = r5c_recovery_alloc_stripe(
+ conf, stripe_sect);
+ }
+ if (!sh) {
+ pr_debug("md/raid:%s: Increasing stripe cache size to %d to recovery data on journal.\n",
+ mdname(mddev),
+ conf->min_nr_stripes * 2);
+ raid5_set_cache_size(mddev,
+ conf->min_nr_stripes * 2);
+ sh = r5c_recovery_alloc_stripe(conf,
+ stripe_sect);
+ }
+ if (!sh) {
+ pr_err("md/raid:%s: Cannot get enough stripes due to memory pressure. Recovery failed.\n",
+ mdname(mddev));
+ return -ENOMEM;
+ }
+ list_add_tail(&sh->lru, cached_stripe_list);
+ }
+
+ if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
+ if (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
+ test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags)) {
+ r5l_recovery_replay_one_stripe(conf, sh, ctx);
+ list_move_tail(&sh->lru, cached_stripe_list);
+ }
+ r5l_recovery_load_data(log, sh, ctx, payload,
+ log_offset);
+ } else if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)
+ r5l_recovery_load_parity(log, sh, ctx, payload,
+ log_offset);
+ else
+ return -EINVAL;
+
+ log_offset = r5l_ring_add(log, log_offset,
+ le32_to_cpu(payload->size));
+
+ mb_offset += sizeof(struct r5l_payload_data_parity) +
+ sizeof(__le32) *
+ (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
+ }
+
+ return 0;
+}
+
+/*
+ * Load the stripe into cache. The stripe will be written out later by
+ * the stripe cache state machine.
+ */
+static void r5c_recovery_load_one_stripe(struct r5l_log *log,
+ struct stripe_head *sh)
+{
+ struct r5dev *dev;
+ int i;
+
+ for (i = sh->disks; i--; ) {
+ dev = sh->dev + i;
+ if (test_and_clear_bit(R5_Wantwrite, &dev->flags)) {
+ set_bit(R5_InJournal, &dev->flags);
+ set_bit(R5_UPTODATE, &dev->flags);
+ }
+ }
+}
+
+/*
+ * Scan through the log for all to-be-flushed data
+ *
+ * For stripes with data and parity, namely Data-Parity stripe
+ * (STRIPE_R5C_CACHING == 0), we simply replay all the writes.
+ *
+ * For stripes with only data, namely Data-Only stripe
+ * (STRIPE_R5C_CACHING == 1), we load them to stripe cache state machine.
+ *
+ * For a stripe, if we see data after parity, we should discard all previous
+ * data and parity for this stripe, as these data are already flushed to
+ * the array.
+ *
+ * At the end of the scan, we return the new journal_tail, which points to
+ * first data-only stripe on the journal device, or next invalid meta block.
+ */
+static int r5c_recovery_flush_log(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct stripe_head *sh;
+ int ret = 0;
+
+ /* scan through the log */
+ while (1) {
+ if (r5l_recovery_read_meta_block(log, ctx))
+ break;
+
+ ret = r5c_recovery_analyze_meta_block(log, ctx,
+ &ctx->cached_list);
+ /*
+ * -EAGAIN means mismatch in data block, in this case, we still
+ * try scan the next metablock
+ */
+ if (ret && ret != -EAGAIN)
+ break; /* ret == -EINVAL or -ENOMEM */
+ ctx->seq++;
+ ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
+ }
+
+ if (ret == -ENOMEM) {
+ r5c_recovery_drop_stripes(&ctx->cached_list, ctx);
+ return ret;
+ }
+
+ /* replay data-parity stripes */
+ r5c_recovery_replay_stripes(&ctx->cached_list, ctx);
+
+ /* load data-only stripes to stripe cache */
+ list_for_each_entry(sh, &ctx->cached_list, lru) {
+ WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
+ r5c_recovery_load_one_stripe(log, sh);
+ ctx->data_only_stripes++;
+ }
+
+ return 0;
+}
+
+/*
+ * we did a recovery. Now ctx.pos points to an invalid meta block. New
+ * log will start here. but we can't let superblock point to last valid
+ * meta block. The log might looks like:
+ * | meta 1| meta 2| meta 3|
+ * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
+ * superblock points to meta 1, we write a new valid meta 2n. if crash
+ * happens again, new recovery will start from meta 1. Since meta 2n is
+ * valid now, recovery will think meta 3 is valid, which is wrong.
+ * The solution is we create a new meta in meta2 with its seq == meta
+ * 1's seq + 10000 and let superblock points to meta2. The same recovery
+ * will not think meta 3 is a valid meta, because its seq doesn't match
+ */
+
+/*
+ * Before recovery, the log looks like the following
+ *
+ * ---------------------------------------------
+ * | valid log | invalid log |
+ * ---------------------------------------------
+ * ^
+ * |- log->last_checkpoint
+ * |- log->last_cp_seq
+ *
+ * Now we scan through the log until we see invalid entry
+ *
+ * ---------------------------------------------
+ * | valid log | invalid log |
+ * ---------------------------------------------
+ * ^ ^
+ * |- log->last_checkpoint |- ctx->pos
+ * |- log->last_cp_seq |- ctx->seq
+ *
+ * From this point, we need to increase seq number by 10 to avoid
+ * confusing next recovery.
+ *
+ * ---------------------------------------------
+ * | valid log | invalid log |
+ * ---------------------------------------------
+ * ^ ^
+ * |- log->last_checkpoint |- ctx->pos+1
+ * |- log->last_cp_seq |- ctx->seq+10001
+ *
+ * However, it is not safe to start the state machine yet, because data only
+ * parities are not yet secured in RAID. To save these data only parities, we
+ * rewrite them from seq+11.
+ *
+ * -----------------------------------------------------------------
+ * | valid log | data only stripes | invalid log |
+ * -----------------------------------------------------------------
+ * ^ ^
+ * |- log->last_checkpoint |- ctx->pos+n
+ * |- log->last_cp_seq |- ctx->seq+10000+n
+ *
+ * If failure happens again during this process, the recovery can safe start
+ * again from log->last_checkpoint.
+ *
+ * Once data only stripes are rewritten to journal, we move log_tail
+ *
+ * -----------------------------------------------------------------
+ * | old log | data only stripes | invalid log |
+ * -----------------------------------------------------------------
+ * ^ ^
+ * |- log->last_checkpoint |- ctx->pos+n
+ * |- log->last_cp_seq |- ctx->seq+10000+n
+ *
+ * Then we can safely start the state machine. If failure happens from this
+ * point on, the recovery will start from new log->last_checkpoint.
+ */
+static int
+r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct stripe_head *sh;
+ struct mddev *mddev = log->rdev->mddev;
+ struct page *page;
+ sector_t next_checkpoint = MaxSector;
+
+ page = alloc_page(GFP_KERNEL);
+ if (!page) {
+ pr_err("md/raid:%s: cannot allocate memory to rewrite data only stripes\n",
+ mdname(mddev));
+ return -ENOMEM;
+ }
+
+ WARN_ON(list_empty(&ctx->cached_list));
+
+ list_for_each_entry(sh, &ctx->cached_list, lru) {
+ struct r5l_meta_block *mb;
+ int i;
+ int offset;
+ sector_t write_pos;
+
+ WARN_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
+ r5l_recovery_create_empty_meta_block(log, page,
+ ctx->pos, ctx->seq);
+ mb = page_address(page);
+ offset = le32_to_cpu(mb->meta_size);
+ write_pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+
+ for (i = sh->disks; i--; ) {
+ struct r5dev *dev = &sh->dev[i];
+ struct r5l_payload_data_parity *payload;
+ void *addr;
+
+ if (test_bit(R5_InJournal, &dev->flags)) {
+ payload = (void *)mb + offset;
+ payload->header.type = cpu_to_le16(
+ R5LOG_PAYLOAD_DATA);
+ payload->size = cpu_to_le32(BLOCK_SECTORS);
+ payload->location = cpu_to_le64(
+ raid5_compute_blocknr(sh, i, 0));
+ addr = kmap_atomic(dev->page);
+ payload->checksum[0] = cpu_to_le32(
+ crc32c_le(log->uuid_checksum, addr,
+ PAGE_SIZE));
+ kunmap_atomic(addr);
+ sync_page_io(log->rdev, write_pos, PAGE_SIZE,
+ dev->page, REQ_OP_WRITE, 0, false);
+ write_pos = r5l_ring_add(log, write_pos,
+ BLOCK_SECTORS);
+ offset += sizeof(__le32) +
+ sizeof(struct r5l_payload_data_parity);
+
+ }
+ }
+ mb->meta_size = cpu_to_le32(offset);
+ mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
+ mb, PAGE_SIZE));
+ sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page,
+ REQ_OP_WRITE, REQ_SYNC | REQ_FUA, false);
+ sh->log_start = ctx->pos;
+ list_add_tail(&sh->r5c, &log->stripe_in_journal_list);
+ atomic_inc(&log->stripe_in_journal_count);
+ ctx->pos = write_pos;
+ ctx->seq += 1;
+ next_checkpoint = sh->log_start;
+ }
+ log->next_checkpoint = next_checkpoint;
+ __free_page(page);
+ return 0;
+}
+
+static void r5c_recovery_flush_data_only_stripes(struct r5l_log *log,
+ struct r5l_recovery_ctx *ctx)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+ struct stripe_head *sh, *next;
+
+ if (ctx->data_only_stripes == 0)
+ return;
+
+ log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_BACK;
+
+ list_for_each_entry_safe(sh, next, &ctx->cached_list, lru) {
+ r5c_make_stripe_write_out(sh);
+ set_bit(STRIPE_HANDLE, &sh->state);
+ list_del_init(&sh->lru);
+ raid5_release_stripe(sh);
+ }
+
+ /* reuse conf->wait_for_quiescent in recovery */
+ wait_event(conf->wait_for_quiescent,
+ atomic_read(&conf->active_stripes) == 0);
+
+ log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
+}
+
+static int r5l_recovery_log(struct r5l_log *log)
+{
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5l_recovery_ctx *ctx;
+ int ret;
+ sector_t pos;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->pos = log->last_checkpoint;
+ ctx->seq = log->last_cp_seq;
+ INIT_LIST_HEAD(&ctx->cached_list);
+ ctx->meta_page = alloc_page(GFP_KERNEL);
+
+ if (!ctx->meta_page) {
+ ret = -ENOMEM;
+ goto meta_page;
+ }
+
+ if (r5l_recovery_allocate_ra_pool(log, ctx) != 0) {
+ ret = -ENOMEM;
+ goto ra_pool;
+ }
+
+ ret = r5c_recovery_flush_log(log, ctx);
+
+ if (ret)
+ goto error;
+
+ pos = ctx->pos;
+ ctx->seq += 10000;
+
+ if ((ctx->data_only_stripes == 0) && (ctx->data_parity_stripes == 0))
+ pr_info("md/raid:%s: starting from clean shutdown\n",
+ mdname(mddev));
+ else
+ pr_info("md/raid:%s: recovering %d data-only stripes and %d data-parity stripes\n",
+ mdname(mddev), ctx->data_only_stripes,
+ ctx->data_parity_stripes);
+
+ if (ctx->data_only_stripes == 0) {
+ log->next_checkpoint = ctx->pos;
+ r5l_log_write_empty_meta_block(log, ctx->pos, ctx->seq++);
+ ctx->pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
+ } else if (r5c_recovery_rewrite_data_only_stripes(log, ctx)) {
+ pr_err("md/raid:%s: failed to rewrite stripes to journal\n",
+ mdname(mddev));
+ ret = -EIO;
+ goto error;
+ }
+
+ log->log_start = ctx->pos;
+ log->seq = ctx->seq;
+ log->last_checkpoint = pos;
+ r5l_write_super(log, pos);
+
+ r5c_recovery_flush_data_only_stripes(log, ctx);
+ ret = 0;
+error:
+ r5l_recovery_free_ra_pool(log, ctx);
+ra_pool:
+ __free_page(ctx->meta_page);
+meta_page:
+ kfree(ctx);
+ return ret;
+}
+
+static void r5l_write_super(struct r5l_log *log, sector_t cp)
+{
+ struct mddev *mddev = log->rdev->mddev;
+
+ log->rdev->journal_tail = cp;
+ set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
+}
+
+static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
+{
+ struct r5conf *conf;
+ int ret;
+
+ ret = mddev_lock(mddev);
+ if (ret)
+ return ret;
+
+ conf = mddev->private;
+ if (!conf || !conf->log) {
+ mddev_unlock(mddev);
+ return 0;
+ }
+
+ switch (conf->log->r5c_journal_mode) {
+ case R5C_JOURNAL_MODE_WRITE_THROUGH:
+ ret = snprintf(
+ page, PAGE_SIZE, "[%s] %s\n",
+ r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
+ r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
+ break;
+ case R5C_JOURNAL_MODE_WRITE_BACK:
+ ret = snprintf(
+ page, PAGE_SIZE, "%s [%s]\n",
+ r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
+ r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
+ break;
+ default:
+ ret = 0;
+ }
+ mddev_unlock(mddev);
+ return ret;
+}
+
+/*
+ * Set journal cache mode on @mddev (external API initially needed by dm-raid).
+ *
+ * @mode as defined in 'enum r5c_journal_mode'.
+ *
+ */
+int r5c_journal_mode_set(struct mddev *mddev, int mode)
+{
+ struct r5conf *conf;
+
+ if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
+ mode > R5C_JOURNAL_MODE_WRITE_BACK)
+ return -EINVAL;
+
+ conf = mddev->private;
+ if (!conf || !conf->log)
+ return -ENODEV;
+
+ if (raid5_calc_degraded(conf) > 0 &&
+ mode == R5C_JOURNAL_MODE_WRITE_BACK)
+ return -EINVAL;
+
+ mddev_suspend(mddev);
+ conf->log->r5c_journal_mode = mode;
+ mddev_resume(mddev);
+
+ pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
+ mdname(mddev), mode, r5c_journal_mode_str[mode]);
+ return 0;
+}
+EXPORT_SYMBOL(r5c_journal_mode_set);
+
+static ssize_t r5c_journal_mode_store(struct mddev *mddev,
+ const char *page, size_t length)
+{
+ int mode = ARRAY_SIZE(r5c_journal_mode_str);
+ size_t len = length;
+ int ret;
+
+ if (len < 2)
+ return -EINVAL;
+
+ if (page[len - 1] == '\n')
+ len--;
+
+ while (mode--)
+ if (strlen(r5c_journal_mode_str[mode]) == len &&
+ !strncmp(page, r5c_journal_mode_str[mode], len))
+ break;
+ ret = mddev_lock(mddev);
+ if (ret)
+ return ret;
+ ret = r5c_journal_mode_set(mddev, mode);
+ mddev_unlock(mddev);
+ return ret ?: length;
+}
+
+struct md_sysfs_entry
+r5c_journal_mode = __ATTR(journal_mode, 0644,
+ r5c_journal_mode_show, r5c_journal_mode_store);
+
+/*
+ * Try handle write operation in caching phase. This function should only
+ * be called in write-back mode.
+ *
+ * If all outstanding writes can be handled in caching phase, returns 0
+ * If writes requires write-out phase, call r5c_make_stripe_write_out()
+ * and returns -EAGAIN
+ */
+int r5c_try_caching_write(struct r5conf *conf,
+ struct stripe_head *sh,
+ struct stripe_head_state *s,
+ int disks)
+{
+ struct r5l_log *log = conf->log;
+ int i;
+ struct r5dev *dev;
+ int to_cache = 0;
+ void **pslot;
+ sector_t tree_index;
+ int ret;
+ uintptr_t refcount;
+
+ BUG_ON(!r5c_is_writeback(log));
+
+ if (!test_bit(STRIPE_R5C_CACHING, &sh->state)) {
+ /*
+ * There are two different scenarios here:
+ * 1. The stripe has some data cached, and it is sent to
+ * write-out phase for reclaim
+ * 2. The stripe is clean, and this is the first write
+ *
+ * For 1, return -EAGAIN, so we continue with
+ * handle_stripe_dirtying().
+ *
+ * For 2, set STRIPE_R5C_CACHING and continue with caching
+ * write.
+ */
+
+ /* case 1: anything injournal or anything in written */
+ if (s->injournal > 0 || s->written > 0)
+ return -EAGAIN;
+ /* case 2 */
+ set_bit(STRIPE_R5C_CACHING, &sh->state);
+ }
+
+ /*
+ * When run in degraded mode, array is set to write-through mode.
+ * This check helps drain pending write safely in the transition to
+ * write-through mode.
+ *
+ * When a stripe is syncing, the write is also handled in write
+ * through mode.
+ */
+ if (s->failed || test_bit(STRIPE_SYNCING, &sh->state)) {
+ r5c_make_stripe_write_out(sh);
+ return -EAGAIN;
+ }
+
+ for (i = disks; i--; ) {
+ dev = &sh->dev[i];
+ /* if non-overwrite, use writing-out phase */
+ if (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags) &&
+ !test_bit(R5_InJournal, &dev->flags)) {
+ r5c_make_stripe_write_out(sh);
+ return -EAGAIN;
+ }
+ }
+
+ /* if the stripe is not counted in big_stripe_tree, add it now */
+ if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
+ !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ tree_index = r5c_tree_index(conf, sh->sector);
+ spin_lock(&log->tree_lock);
+ pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
+ tree_index);
+ if (pslot) {
+ refcount = (uintptr_t)radix_tree_deref_slot_protected(
+ pslot, &log->tree_lock) >>
+ R5C_RADIX_COUNT_SHIFT;
+ radix_tree_replace_slot(
+ &log->big_stripe_tree, pslot,
+ (void *)((refcount + 1) << R5C_RADIX_COUNT_SHIFT));
+ } else {
+ /*
+ * this radix_tree_insert can fail safely, so no
+ * need to call radix_tree_preload()
+ */
+ ret = radix_tree_insert(
+ &log->big_stripe_tree, tree_index,
+ (void *)(1 << R5C_RADIX_COUNT_SHIFT));
+ if (ret) {
+ spin_unlock(&log->tree_lock);
+ r5c_make_stripe_write_out(sh);
+ return -EAGAIN;
+ }
+ }
+ spin_unlock(&log->tree_lock);
+
+ /*
+ * set STRIPE_R5C_PARTIAL_STRIPE, this shows the stripe is
+ * counted in the radix tree
+ */
+ set_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state);
+ atomic_inc(&conf->r5c_cached_partial_stripes);
+ }
+
+ for (i = disks; i--; ) {
+ dev = &sh->dev[i];
+ if (dev->towrite) {
+ set_bit(R5_Wantwrite, &dev->flags);
+ set_bit(R5_Wantdrain, &dev->flags);
+ set_bit(R5_LOCKED, &dev->flags);
+ to_cache++;
+ }
+ }
+
+ if (to_cache) {
+ set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
+ /*
+ * set STRIPE_LOG_TRAPPED, which triggers r5c_cache_data()
+ * in ops_run_io(). STRIPE_LOG_TRAPPED will be cleared in
+ * r5c_handle_data_cached()
+ */
+ set_bit(STRIPE_LOG_TRAPPED, &sh->state);
+ }
+
+ return 0;
+}
+
+/*
+ * free extra pages (orig_page) we allocated for prexor
+ */
+void r5c_release_extra_page(struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int i;
+ bool using_disk_info_extra_page;
+
+ using_disk_info_extra_page =
+ sh->dev[0].orig_page == conf->disks[0].extra_page;
+
+ for (i = sh->disks; i--; )
+ if (sh->dev[i].page != sh->dev[i].orig_page) {
+ struct page *p = sh->dev[i].orig_page;
+
+ sh->dev[i].orig_page = sh->dev[i].page;
+ clear_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
+
+ if (!using_disk_info_extra_page)
+ put_page(p);
+ }
+
+ if (using_disk_info_extra_page) {
+ clear_bit(R5C_EXTRA_PAGE_IN_USE, &conf->cache_state);
+ md_wakeup_thread(conf->mddev->thread);
+ }
+}
+
+void r5c_use_extra_page(struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int i;
+ struct r5dev *dev;
+
+ for (i = sh->disks; i--; ) {
+ dev = &sh->dev[i];
+ if (dev->orig_page != dev->page)
+ put_page(dev->orig_page);
+ dev->orig_page = conf->disks[i].extra_page;
+ }
+}
+
+/*
+ * clean up the stripe (clear R5_InJournal for dev[pd_idx] etc.) after the
+ * stripe is committed to RAID disks.
+ */
+void r5c_finish_stripe_write_out(struct r5conf *conf,
+ struct stripe_head *sh,
+ struct stripe_head_state *s)
+{
+ struct r5l_log *log = conf->log;
+ int i;
+ int do_wakeup = 0;
+ sector_t tree_index;
+ void **pslot;
+ uintptr_t refcount;
+
+ if (!log || !test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags))
+ return;
+
+ WARN_ON(test_bit(STRIPE_R5C_CACHING, &sh->state));
+ clear_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags);
+
+ if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+ return;
+
+ for (i = sh->disks; i--; ) {
+ clear_bit(R5_InJournal, &sh->dev[i].flags);
+ if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
+ do_wakeup = 1;
+ }
+
+ /*
+ * analyse_stripe() runs before r5c_finish_stripe_write_out(),
+ * We updated R5_InJournal, so we also update s->injournal.
+ */
+ s->injournal = 0;
+
+ if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
+ if (atomic_dec_and_test(&conf->pending_full_writes))
+ md_wakeup_thread(conf->mddev->thread);
+
+ if (do_wakeup)
+ wake_up(&conf->wait_for_overlap);
+
+ spin_lock_irq(&log->stripe_in_journal_lock);
+ list_del_init(&sh->r5c);
+ spin_unlock_irq(&log->stripe_in_journal_lock);
+ sh->log_start = MaxSector;
+
+ atomic_dec(&log->stripe_in_journal_count);
+ r5c_update_log_state(log);
+
+ /* stop counting this stripe in big_stripe_tree */
+ if (test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) ||
+ test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ tree_index = r5c_tree_index(conf, sh->sector);
+ spin_lock(&log->tree_lock);
+ pslot = radix_tree_lookup_slot(&log->big_stripe_tree,
+ tree_index);
+ BUG_ON(pslot == NULL);
+ refcount = (uintptr_t)radix_tree_deref_slot_protected(
+ pslot, &log->tree_lock) >>
+ R5C_RADIX_COUNT_SHIFT;
+ if (refcount == 1)
+ radix_tree_delete(&log->big_stripe_tree, tree_index);
+ else
+ radix_tree_replace_slot(
+ &log->big_stripe_tree, pslot,
+ (void *)((refcount - 1) << R5C_RADIX_COUNT_SHIFT));
+ spin_unlock(&log->tree_lock);
+ }
+
+ if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) {
+ BUG_ON(atomic_read(&conf->r5c_cached_partial_stripes) == 0);
+ atomic_dec(&conf->r5c_flushing_partial_stripes);
+ atomic_dec(&conf->r5c_cached_partial_stripes);
+ }
+
+ if (test_and_clear_bit(STRIPE_R5C_FULL_STRIPE, &sh->state)) {
+ BUG_ON(atomic_read(&conf->r5c_cached_full_stripes) == 0);
+ atomic_dec(&conf->r5c_flushing_full_stripes);
+ atomic_dec(&conf->r5c_cached_full_stripes);
+ }
+
+ r5l_append_flush_payload(log, sh->sector);
+ /* stripe is flused to raid disks, we can do resync now */
+ if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
+ set_bit(STRIPE_HANDLE, &sh->state);
+}
+
+int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh)
+{
+ struct r5conf *conf = sh->raid_conf;
+ int pages = 0;
+ int reserve;
+ int i;
+ int ret = 0;
+
+ BUG_ON(!log);
+
+ for (i = 0; i < sh->disks; i++) {
+ void *addr;
+
+ if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
+ continue;
+ addr = kmap_atomic(sh->dev[i].page);
+ sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
+ addr, PAGE_SIZE);
+ kunmap_atomic(addr);
+ pages++;
+ }
+ WARN_ON(pages == 0);
+
+ /*
+ * The stripe must enter state machine again to call endio, so
+ * don't delay.
+ */
+ clear_bit(STRIPE_DELAYED, &sh->state);
+ atomic_inc(&sh->count);
+
+ mutex_lock(&log->io_mutex);
+ /* meta + data */
+ reserve = (1 + pages) << (PAGE_SHIFT - 9);
+
+ if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
+ sh->log_start == MaxSector)
+ r5l_add_no_space_stripe(log, sh);
+ else if (!r5l_has_free_space(log, reserve)) {
+ if (sh->log_start == log->last_checkpoint)
+ BUG();
+ else
+ r5l_add_no_space_stripe(log, sh);
+ } else {
+ ret = r5l_log_stripe(log, sh, pages, 0);
+ if (ret) {
+ spin_lock_irq(&log->io_list_lock);
+ list_add_tail(&sh->log_list, &log->no_mem_stripes);
+ spin_unlock_irq(&log->io_list_lock);
+ }
+ }
+
+ mutex_unlock(&log->io_mutex);
+ return 0;
+}
+
+/* check whether this big stripe is in write back cache. */
+bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect)
+{
+ struct r5l_log *log = conf->log;
+ sector_t tree_index;
+ void *slot;
+
+ if (!log)
+ return false;
+
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ tree_index = r5c_tree_index(conf, sect);
+ slot = radix_tree_lookup(&log->big_stripe_tree, tree_index);
+ return slot != NULL;
+}
+
+static int r5l_load_log(struct r5l_log *log)
+{
+ struct md_rdev *rdev = log->rdev;
+ struct page *page;
+ struct r5l_meta_block *mb;
+ sector_t cp = log->rdev->journal_tail;
+ u32 stored_crc, expected_crc;
+ bool create_super = false;
+ int ret = 0;
+
+ /* Make sure it's valid */
+ if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
+ cp = 0;
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+
+ if (!sync_page_io(rdev, cp, PAGE_SIZE, page, REQ_OP_READ, 0, false)) {
+ ret = -EIO;
+ goto ioerr;
+ }
+ mb = page_address(page);
+
+ if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
+ mb->version != R5LOG_VERSION) {
+ create_super = true;
+ goto create;
+ }
+ stored_crc = le32_to_cpu(mb->checksum);
+ mb->checksum = 0;
+ expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
+ if (stored_crc != expected_crc) {
+ create_super = true;
+ goto create;
+ }
+ if (le64_to_cpu(mb->position) != cp) {
+ create_super = true;
+ goto create;
+ }
+create:
+ if (create_super) {
+ log->last_cp_seq = prandom_u32();
+ cp = 0;
+ r5l_log_write_empty_meta_block(log, cp, log->last_cp_seq);
+ /*
+ * Make sure super points to correct address. Log might have
+ * data very soon. If super hasn't correct log tail address,
+ * recovery can't find the log
+ */
+ r5l_write_super(log, cp);
+ } else
+ log->last_cp_seq = le64_to_cpu(mb->seq);
+
+ log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
+ log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT;
+ if (log->max_free_space > RECLAIM_MAX_FREE_SPACE)
+ log->max_free_space = RECLAIM_MAX_FREE_SPACE;
+ log->last_checkpoint = cp;
+
+ __free_page(page);
+
+ if (create_super) {
+ log->log_start = r5l_ring_add(log, cp, BLOCK_SECTORS);
+ log->seq = log->last_cp_seq + 1;
+ log->next_checkpoint = cp;
+ } else
+ ret = r5l_recovery_log(log);
+
+ r5c_update_log_state(log);
+ return ret;
+ioerr:
+ __free_page(page);
+ return ret;
+}
+
+int r5l_start(struct r5l_log *log)
+{
+ int ret;
+
+ if (!log)
+ return 0;
+
+ ret = r5l_load_log(log);
+ if (ret) {
+ struct mddev *mddev = log->rdev->mddev;
+ struct r5conf *conf = mddev->private;
+
+ r5l_exit_log(conf);
+ }
+ return ret;
+}
+
+void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
+{
+ struct r5conf *conf = mddev->private;
+ struct r5l_log *log = conf->log;
+
+ if (!log)
+ return;
+
+ if ((raid5_calc_degraded(conf) > 0 ||
+ test_bit(Journal, &rdev->flags)) &&
+ conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_BACK)
+ schedule_work(&log->disable_writeback_work);
+}
+
+int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
+{
+ struct request_queue *q = bdev_get_queue(rdev->bdev);
+ struct r5l_log *log;
+ char b[BDEVNAME_SIZE];
+ int ret;
+
+ pr_debug("md/raid:%s: using device %s as journal\n",
+ mdname(conf->mddev), bdevname(rdev->bdev, b));
+
+ if (PAGE_SIZE != 4096)
+ return -EINVAL;
+
+ /*
+ * The PAGE_SIZE must be big enough to hold 1 r5l_meta_block and
+ * raid_disks r5l_payload_data_parity.
+ *
+ * Write journal and cache does not work for very big array
+ * (raid_disks > 203)
+ */
+ if (sizeof(struct r5l_meta_block) +
+ ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) *
+ conf->raid_disks) > PAGE_SIZE) {
+ pr_err("md/raid:%s: write journal/cache doesn't work for array with %d disks\n",
+ mdname(conf->mddev), conf->raid_disks);
+ return -EINVAL;
+ }
+
+ log = kzalloc(sizeof(*log), GFP_KERNEL);
+ if (!log)
+ return -ENOMEM;
+ log->rdev = rdev;
+
+ log->need_cache_flush = test_bit(QUEUE_FLAG_WC, &q->queue_flags) != 0;
+
+ log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
+ sizeof(rdev->mddev->uuid));
+
+ mutex_init(&log->io_mutex);
+
+ spin_lock_init(&log->io_list_lock);
+ INIT_LIST_HEAD(&log->running_ios);
+ INIT_LIST_HEAD(&log->io_end_ios);
+ INIT_LIST_HEAD(&log->flushing_ios);
+ INIT_LIST_HEAD(&log->finished_ios);
+ bio_init(&log->flush_bio, NULL, 0);
+
+ log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
+ if (!log->io_kc)
+ goto io_kc;
+
+ ret = mempool_init_slab_pool(&log->io_pool, R5L_POOL_SIZE, log->io_kc);
+ if (ret)
+ goto io_pool;
+
+ ret = bioset_init(&log->bs, R5L_POOL_SIZE, 0, BIOSET_NEED_BVECS);
+ if (ret)
+ goto io_bs;
+
+ ret = mempool_init_page_pool(&log->meta_pool, R5L_POOL_SIZE, 0);
+ if (ret)
+ goto out_mempool;
+
+ spin_lock_init(&log->tree_lock);
+ INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
+
+ log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
+ log->rdev->mddev, "reclaim");
+ if (!log->reclaim_thread)
+ goto reclaim_thread;
+ log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
+
+ init_waitqueue_head(&log->iounit_wait);
+
+ INIT_LIST_HEAD(&log->no_mem_stripes);
+
+ INIT_LIST_HEAD(&log->no_space_stripes);
+ spin_lock_init(&log->no_space_stripes_lock);
+
+ INIT_WORK(&log->deferred_io_work, r5l_submit_io_async);
+ INIT_WORK(&log->disable_writeback_work, r5c_disable_writeback_async);
+
+ log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
+ INIT_LIST_HEAD(&log->stripe_in_journal_list);
+ spin_lock_init(&log->stripe_in_journal_lock);
+ atomic_set(&log->stripe_in_journal_count, 0);
+
+ rcu_assign_pointer(conf->log, log);
+
+ set_bit(MD_HAS_JOURNAL, &conf->mddev->flags);
+ return 0;
+
+ rcu_assign_pointer(conf->log, NULL);
+ md_unregister_thread(&log->reclaim_thread);
+reclaim_thread:
+ mempool_exit(&log->meta_pool);
+out_mempool:
+ bioset_exit(&log->bs);
+io_bs:
+ mempool_exit(&log->io_pool);
+io_pool:
+ kmem_cache_destroy(log->io_kc);
+io_kc:
+ kfree(log);
+ return -EINVAL;
+}
+
+void r5l_exit_log(struct r5conf *conf)
+{
+ struct r5l_log *log = conf->log;
+
+ conf->log = NULL;
+ synchronize_rcu();
+
+ /* Ensure disable_writeback_work wakes up and exits */
+ wake_up(&conf->mddev->sb_wait);
+ flush_work(&log->disable_writeback_work);
+ md_unregister_thread(&log->reclaim_thread);
+ mempool_exit(&log->meta_pool);
+ bioset_exit(&log->bs);
+ mempool_exit(&log->io_pool);
+ kmem_cache_destroy(log->io_kc);
+ kfree(log);
+}