v4.19.13 snapshot.
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
new file mode 100644
index 0000000..ca4902c
--- /dev/null
+++ b/fs/btrfs/file.c
@@ -0,0 +1,3370 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/falloc.h>
+#include <linux/writeback.h>
+#include <linux/compat.h>
+#include <linux/slab.h>
+#include <linux/btrfs.h>
+#include <linux/uio.h>
+#include <linux/iversion.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "print-tree.h"
+#include "tree-log.h"
+#include "locking.h"
+#include "volumes.h"
+#include "qgroup.h"
+#include "compression.h"
+
+static struct kmem_cache *btrfs_inode_defrag_cachep;
+/*
+ * when auto defrag is enabled we
+ * queue up these defrag structs to remember which
+ * inodes need defragging passes
+ */
+struct inode_defrag {
+ struct rb_node rb_node;
+ /* objectid */
+ u64 ino;
+ /*
+ * transid where the defrag was added, we search for
+ * extents newer than this
+ */
+ u64 transid;
+
+ /* root objectid */
+ u64 root;
+
+ /* last offset we were able to defrag */
+ u64 last_offset;
+
+ /* if we've wrapped around back to zero once already */
+ int cycled;
+};
+
+static int __compare_inode_defrag(struct inode_defrag *defrag1,
+ struct inode_defrag *defrag2)
+{
+ if (defrag1->root > defrag2->root)
+ return 1;
+ else if (defrag1->root < defrag2->root)
+ return -1;
+ else if (defrag1->ino > defrag2->ino)
+ return 1;
+ else if (defrag1->ino < defrag2->ino)
+ return -1;
+ else
+ return 0;
+}
+
+/* pop a record for an inode into the defrag tree. The lock
+ * must be held already
+ *
+ * If you're inserting a record for an older transid than an
+ * existing record, the transid already in the tree is lowered
+ *
+ * If an existing record is found the defrag item you
+ * pass in is freed
+ */
+static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
+ struct inode_defrag *defrag)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct inode_defrag *entry;
+ struct rb_node **p;
+ struct rb_node *parent = NULL;
+ int ret;
+
+ p = &fs_info->defrag_inodes.rb_node;
+ while (*p) {
+ parent = *p;
+ entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+ ret = __compare_inode_defrag(defrag, entry);
+ if (ret < 0)
+ p = &parent->rb_left;
+ else if (ret > 0)
+ p = &parent->rb_right;
+ else {
+ /* if we're reinserting an entry for
+ * an old defrag run, make sure to
+ * lower the transid of our existing record
+ */
+ if (defrag->transid < entry->transid)
+ entry->transid = defrag->transid;
+ if (defrag->last_offset > entry->last_offset)
+ entry->last_offset = defrag->last_offset;
+ return -EEXIST;
+ }
+ }
+ set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
+ rb_link_node(&defrag->rb_node, parent, p);
+ rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
+ return 0;
+}
+
+static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
+{
+ if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
+ return 0;
+
+ if (btrfs_fs_closing(fs_info))
+ return 0;
+
+ return 1;
+}
+
+/*
+ * insert a defrag record for this inode if auto defrag is
+ * enabled
+ */
+int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
+ struct btrfs_inode *inode)
+{
+ struct btrfs_root *root = inode->root;
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct inode_defrag *defrag;
+ u64 transid;
+ int ret;
+
+ if (!__need_auto_defrag(fs_info))
+ return 0;
+
+ if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
+ return 0;
+
+ if (trans)
+ transid = trans->transid;
+ else
+ transid = inode->root->last_trans;
+
+ defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
+ if (!defrag)
+ return -ENOMEM;
+
+ defrag->ino = btrfs_ino(inode);
+ defrag->transid = transid;
+ defrag->root = root->root_key.objectid;
+
+ spin_lock(&fs_info->defrag_inodes_lock);
+ if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
+ /*
+ * If we set IN_DEFRAG flag and evict the inode from memory,
+ * and then re-read this inode, this new inode doesn't have
+ * IN_DEFRAG flag. At the case, we may find the existed defrag.
+ */
+ ret = __btrfs_add_inode_defrag(inode, defrag);
+ if (ret)
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+ } else {
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+ }
+ spin_unlock(&fs_info->defrag_inodes_lock);
+ return 0;
+}
+
+/*
+ * Requeue the defrag object. If there is a defrag object that points to
+ * the same inode in the tree, we will merge them together (by
+ * __btrfs_add_inode_defrag()) and free the one that we want to requeue.
+ */
+static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
+ struct inode_defrag *defrag)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ int ret;
+
+ if (!__need_auto_defrag(fs_info))
+ goto out;
+
+ /*
+ * Here we don't check the IN_DEFRAG flag, because we need merge
+ * them together.
+ */
+ spin_lock(&fs_info->defrag_inodes_lock);
+ ret = __btrfs_add_inode_defrag(inode, defrag);
+ spin_unlock(&fs_info->defrag_inodes_lock);
+ if (ret)
+ goto out;
+ return;
+out:
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+}
+
+/*
+ * pick the defragable inode that we want, if it doesn't exist, we will get
+ * the next one.
+ */
+static struct inode_defrag *
+btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
+{
+ struct inode_defrag *entry = NULL;
+ struct inode_defrag tmp;
+ struct rb_node *p;
+ struct rb_node *parent = NULL;
+ int ret;
+
+ tmp.ino = ino;
+ tmp.root = root;
+
+ spin_lock(&fs_info->defrag_inodes_lock);
+ p = fs_info->defrag_inodes.rb_node;
+ while (p) {
+ parent = p;
+ entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+ ret = __compare_inode_defrag(&tmp, entry);
+ if (ret < 0)
+ p = parent->rb_left;
+ else if (ret > 0)
+ p = parent->rb_right;
+ else
+ goto out;
+ }
+
+ if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
+ parent = rb_next(parent);
+ if (parent)
+ entry = rb_entry(parent, struct inode_defrag, rb_node);
+ else
+ entry = NULL;
+ }
+out:
+ if (entry)
+ rb_erase(parent, &fs_info->defrag_inodes);
+ spin_unlock(&fs_info->defrag_inodes_lock);
+ return entry;
+}
+
+void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+ struct inode_defrag *defrag;
+ struct rb_node *node;
+
+ spin_lock(&fs_info->defrag_inodes_lock);
+ node = rb_first(&fs_info->defrag_inodes);
+ while (node) {
+ rb_erase(node, &fs_info->defrag_inodes);
+ defrag = rb_entry(node, struct inode_defrag, rb_node);
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+
+ cond_resched_lock(&fs_info->defrag_inodes_lock);
+
+ node = rb_first(&fs_info->defrag_inodes);
+ }
+ spin_unlock(&fs_info->defrag_inodes_lock);
+}
+
+#define BTRFS_DEFRAG_BATCH 1024
+
+static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
+ struct inode_defrag *defrag)
+{
+ struct btrfs_root *inode_root;
+ struct inode *inode;
+ struct btrfs_key key;
+ struct btrfs_ioctl_defrag_range_args range;
+ int num_defrag;
+ int index;
+ int ret;
+
+ /* get the inode */
+ key.objectid = defrag->root;
+ key.type = BTRFS_ROOT_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ index = srcu_read_lock(&fs_info->subvol_srcu);
+
+ inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
+ if (IS_ERR(inode_root)) {
+ ret = PTR_ERR(inode_root);
+ goto cleanup;
+ }
+
+ key.objectid = defrag->ino;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
+ if (IS_ERR(inode)) {
+ ret = PTR_ERR(inode);
+ goto cleanup;
+ }
+ srcu_read_unlock(&fs_info->subvol_srcu, index);
+
+ /* do a chunk of defrag */
+ clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
+ memset(&range, 0, sizeof(range));
+ range.len = (u64)-1;
+ range.start = defrag->last_offset;
+
+ sb_start_write(fs_info->sb);
+ num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
+ BTRFS_DEFRAG_BATCH);
+ sb_end_write(fs_info->sb);
+ /*
+ * if we filled the whole defrag batch, there
+ * must be more work to do. Queue this defrag
+ * again
+ */
+ if (num_defrag == BTRFS_DEFRAG_BATCH) {
+ defrag->last_offset = range.start;
+ btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
+ } else if (defrag->last_offset && !defrag->cycled) {
+ /*
+ * we didn't fill our defrag batch, but
+ * we didn't start at zero. Make sure we loop
+ * around to the start of the file.
+ */
+ defrag->last_offset = 0;
+ defrag->cycled = 1;
+ btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
+ } else {
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+ }
+
+ iput(inode);
+ return 0;
+cleanup:
+ srcu_read_unlock(&fs_info->subvol_srcu, index);
+ kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+ return ret;
+}
+
+/*
+ * run through the list of inodes in the FS that need
+ * defragging
+ */
+int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+ struct inode_defrag *defrag;
+ u64 first_ino = 0;
+ u64 root_objectid = 0;
+
+ atomic_inc(&fs_info->defrag_running);
+ while (1) {
+ /* Pause the auto defragger. */
+ if (test_bit(BTRFS_FS_STATE_REMOUNTING,
+ &fs_info->fs_state))
+ break;
+
+ if (!__need_auto_defrag(fs_info))
+ break;
+
+ /* find an inode to defrag */
+ defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
+ first_ino);
+ if (!defrag) {
+ if (root_objectid || first_ino) {
+ root_objectid = 0;
+ first_ino = 0;
+ continue;
+ } else {
+ break;
+ }
+ }
+
+ first_ino = defrag->ino + 1;
+ root_objectid = defrag->root;
+
+ __btrfs_run_defrag_inode(fs_info, defrag);
+ }
+ atomic_dec(&fs_info->defrag_running);
+
+ /*
+ * during unmount, we use the transaction_wait queue to
+ * wait for the defragger to stop
+ */
+ wake_up(&fs_info->transaction_wait);
+ return 0;
+}
+
+/* simple helper to fault in pages and copy. This should go away
+ * and be replaced with calls into generic code.
+ */
+static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
+ struct page **prepared_pages,
+ struct iov_iter *i)
+{
+ size_t copied = 0;
+ size_t total_copied = 0;
+ int pg = 0;
+ int offset = pos & (PAGE_SIZE - 1);
+
+ while (write_bytes > 0) {
+ size_t count = min_t(size_t,
+ PAGE_SIZE - offset, write_bytes);
+ struct page *page = prepared_pages[pg];
+ /*
+ * Copy data from userspace to the current page
+ */
+ copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
+
+ /* Flush processor's dcache for this page */
+ flush_dcache_page(page);
+
+ /*
+ * if we get a partial write, we can end up with
+ * partially up to date pages. These add
+ * a lot of complexity, so make sure they don't
+ * happen by forcing this copy to be retried.
+ *
+ * The rest of the btrfs_file_write code will fall
+ * back to page at a time copies after we return 0.
+ */
+ if (!PageUptodate(page) && copied < count)
+ copied = 0;
+
+ iov_iter_advance(i, copied);
+ write_bytes -= copied;
+ total_copied += copied;
+
+ /* Return to btrfs_file_write_iter to fault page */
+ if (unlikely(copied == 0))
+ break;
+
+ if (copied < PAGE_SIZE - offset) {
+ offset += copied;
+ } else {
+ pg++;
+ offset = 0;
+ }
+ }
+ return total_copied;
+}
+
+/*
+ * unlocks pages after btrfs_file_write is done with them
+ */
+static void btrfs_drop_pages(struct page **pages, size_t num_pages)
+{
+ size_t i;
+ for (i = 0; i < num_pages; i++) {
+ /* page checked is some magic around finding pages that
+ * have been modified without going through btrfs_set_page_dirty
+ * clear it here. There should be no need to mark the pages
+ * accessed as prepare_pages should have marked them accessed
+ * in prepare_pages via find_or_create_page()
+ */
+ ClearPageChecked(pages[i]);
+ unlock_page(pages[i]);
+ put_page(pages[i]);
+ }
+}
+
+static int btrfs_find_new_delalloc_bytes(struct btrfs_inode *inode,
+ const u64 start,
+ const u64 len,
+ struct extent_state **cached_state)
+{
+ u64 search_start = start;
+ const u64 end = start + len - 1;
+
+ while (search_start < end) {
+ const u64 search_len = end - search_start + 1;
+ struct extent_map *em;
+ u64 em_len;
+ int ret = 0;
+
+ em = btrfs_get_extent(inode, NULL, 0, search_start,
+ search_len, 0);
+ if (IS_ERR(em))
+ return PTR_ERR(em);
+
+ if (em->block_start != EXTENT_MAP_HOLE)
+ goto next;
+
+ em_len = em->len;
+ if (em->start < search_start)
+ em_len -= search_start - em->start;
+ if (em_len > search_len)
+ em_len = search_len;
+
+ ret = set_extent_bit(&inode->io_tree, search_start,
+ search_start + em_len - 1,
+ EXTENT_DELALLOC_NEW,
+ NULL, cached_state, GFP_NOFS);
+next:
+ search_start = extent_map_end(em);
+ free_extent_map(em);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
+/*
+ * after copy_from_user, pages need to be dirtied and we need to make
+ * sure holes are created between the current EOF and the start of
+ * any next extents (if required).
+ *
+ * this also makes the decision about creating an inline extent vs
+ * doing real data extents, marking pages dirty and delalloc as required.
+ */
+int btrfs_dirty_pages(struct inode *inode, struct page **pages,
+ size_t num_pages, loff_t pos, size_t write_bytes,
+ struct extent_state **cached)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ int err = 0;
+ int i;
+ u64 num_bytes;
+ u64 start_pos;
+ u64 end_of_last_block;
+ u64 end_pos = pos + write_bytes;
+ loff_t isize = i_size_read(inode);
+ unsigned int extra_bits = 0;
+
+ start_pos = pos & ~((u64) fs_info->sectorsize - 1);
+ num_bytes = round_up(write_bytes + pos - start_pos,
+ fs_info->sectorsize);
+
+ end_of_last_block = start_pos + num_bytes - 1;
+
+ /*
+ * The pages may have already been dirty, clear out old accounting so
+ * we can set things up properly
+ */
+ clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, end_of_last_block,
+ EXTENT_DIRTY | EXTENT_DELALLOC |
+ EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0, cached);
+
+ if (!btrfs_is_free_space_inode(BTRFS_I(inode))) {
+ if (start_pos >= isize &&
+ !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)) {
+ /*
+ * There can't be any extents following eof in this case
+ * so just set the delalloc new bit for the range
+ * directly.
+ */
+ extra_bits |= EXTENT_DELALLOC_NEW;
+ } else {
+ err = btrfs_find_new_delalloc_bytes(BTRFS_I(inode),
+ start_pos,
+ num_bytes, cached);
+ if (err)
+ return err;
+ }
+ }
+
+ err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
+ extra_bits, cached, 0);
+ if (err)
+ return err;
+
+ for (i = 0; i < num_pages; i++) {
+ struct page *p = pages[i];
+ SetPageUptodate(p);
+ ClearPageChecked(p);
+ set_page_dirty(p);
+ }
+
+ /*
+ * we've only changed i_size in ram, and we haven't updated
+ * the disk i_size. There is no need to log the inode
+ * at this time.
+ */
+ if (end_pos > isize)
+ i_size_write(inode, end_pos);
+ return 0;
+}
+
+/*
+ * this drops all the extents in the cache that intersect the range
+ * [start, end]. Existing extents are split as required.
+ */
+void btrfs_drop_extent_cache(struct btrfs_inode *inode, u64 start, u64 end,
+ int skip_pinned)
+{
+ struct extent_map *em;
+ struct extent_map *split = NULL;
+ struct extent_map *split2 = NULL;
+ struct extent_map_tree *em_tree = &inode->extent_tree;
+ u64 len = end - start + 1;
+ u64 gen;
+ int ret;
+ int testend = 1;
+ unsigned long flags;
+ int compressed = 0;
+ bool modified;
+
+ WARN_ON(end < start);
+ if (end == (u64)-1) {
+ len = (u64)-1;
+ testend = 0;
+ }
+ while (1) {
+ int no_splits = 0;
+
+ modified = false;
+ if (!split)
+ split = alloc_extent_map();
+ if (!split2)
+ split2 = alloc_extent_map();
+ if (!split || !split2)
+ no_splits = 1;
+
+ write_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, start, len);
+ if (!em) {
+ write_unlock(&em_tree->lock);
+ break;
+ }
+ flags = em->flags;
+ gen = em->generation;
+ if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
+ if (testend && em->start + em->len >= start + len) {
+ free_extent_map(em);
+ write_unlock(&em_tree->lock);
+ break;
+ }
+ start = em->start + em->len;
+ if (testend)
+ len = start + len - (em->start + em->len);
+ free_extent_map(em);
+ write_unlock(&em_tree->lock);
+ continue;
+ }
+ compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+ clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+ clear_bit(EXTENT_FLAG_LOGGING, &flags);
+ modified = !list_empty(&em->list);
+ if (no_splits)
+ goto next;
+
+ if (em->start < start) {
+ split->start = em->start;
+ split->len = start - em->start;
+
+ if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+ split->orig_start = em->orig_start;
+ split->block_start = em->block_start;
+
+ if (compressed)
+ split->block_len = em->block_len;
+ else
+ split->block_len = split->len;
+ split->orig_block_len = max(split->block_len,
+ em->orig_block_len);
+ split->ram_bytes = em->ram_bytes;
+ } else {
+ split->orig_start = split->start;
+ split->block_len = 0;
+ split->block_start = em->block_start;
+ split->orig_block_len = 0;
+ split->ram_bytes = split->len;
+ }
+
+ split->generation = gen;
+ split->bdev = em->bdev;
+ split->flags = flags;
+ split->compress_type = em->compress_type;
+ replace_extent_mapping(em_tree, em, split, modified);
+ free_extent_map(split);
+ split = split2;
+ split2 = NULL;
+ }
+ if (testend && em->start + em->len > start + len) {
+ u64 diff = start + len - em->start;
+
+ split->start = start + len;
+ split->len = em->start + em->len - (start + len);
+ split->bdev = em->bdev;
+ split->flags = flags;
+ split->compress_type = em->compress_type;
+ split->generation = gen;
+
+ if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+ split->orig_block_len = max(em->block_len,
+ em->orig_block_len);
+
+ split->ram_bytes = em->ram_bytes;
+ if (compressed) {
+ split->block_len = em->block_len;
+ split->block_start = em->block_start;
+ split->orig_start = em->orig_start;
+ } else {
+ split->block_len = split->len;
+ split->block_start = em->block_start
+ + diff;
+ split->orig_start = em->orig_start;
+ }
+ } else {
+ split->ram_bytes = split->len;
+ split->orig_start = split->start;
+ split->block_len = 0;
+ split->block_start = em->block_start;
+ split->orig_block_len = 0;
+ }
+
+ if (extent_map_in_tree(em)) {
+ replace_extent_mapping(em_tree, em, split,
+ modified);
+ } else {
+ ret = add_extent_mapping(em_tree, split,
+ modified);
+ ASSERT(ret == 0); /* Logic error */
+ }
+ free_extent_map(split);
+ split = NULL;
+ }
+next:
+ if (extent_map_in_tree(em))
+ remove_extent_mapping(em_tree, em);
+ write_unlock(&em_tree->lock);
+
+ /* once for us */
+ free_extent_map(em);
+ /* once for the tree*/
+ free_extent_map(em);
+ }
+ if (split)
+ free_extent_map(split);
+ if (split2)
+ free_extent_map(split2);
+}
+
+/*
+ * this is very complex, but the basic idea is to drop all extents
+ * in the range start - end. hint_block is filled in with a block number
+ * that would be a good hint to the block allocator for this file.
+ *
+ * If an extent intersects the range but is not entirely inside the range
+ * it is either truncated or split. Anything entirely inside the range
+ * is deleted from the tree.
+ */
+int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct inode *inode,
+ struct btrfs_path *path, u64 start, u64 end,
+ u64 *drop_end, int drop_cache,
+ int replace_extent,
+ u32 extent_item_size,
+ int *key_inserted)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ struct btrfs_key new_key;
+ u64 ino = btrfs_ino(BTRFS_I(inode));
+ u64 search_start = start;
+ u64 disk_bytenr = 0;
+ u64 num_bytes = 0;
+ u64 extent_offset = 0;
+ u64 extent_end = 0;
+ u64 last_end = start;
+ int del_nr = 0;
+ int del_slot = 0;
+ int extent_type;
+ int recow;
+ int ret;
+ int modify_tree = -1;
+ int update_refs;
+ int found = 0;
+ int leafs_visited = 0;
+
+ if (drop_cache)
+ btrfs_drop_extent_cache(BTRFS_I(inode), start, end - 1, 0);
+
+ if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
+ modify_tree = 0;
+
+ update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ root == fs_info->tree_root);
+ while (1) {
+ recow = 0;
+ ret = btrfs_lookup_file_extent(trans, root, path, ino,
+ search_start, modify_tree);
+ if (ret < 0)
+ break;
+ if (ret > 0 && path->slots[0] > 0 && search_start == start) {
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
+ if (key.objectid == ino &&
+ key.type == BTRFS_EXTENT_DATA_KEY)
+ path->slots[0]--;
+ }
+ ret = 0;
+ leafs_visited++;
+next_slot:
+ leaf = path->nodes[0];
+ if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+ BUG_ON(del_nr > 0);
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ break;
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ leafs_visited++;
+ leaf = path->nodes[0];
+ recow = 1;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ if (key.objectid > ino)
+ break;
+ if (WARN_ON_ONCE(key.objectid < ino) ||
+ key.type < BTRFS_EXTENT_DATA_KEY) {
+ ASSERT(del_nr == 0);
+ path->slots[0]++;
+ goto next_slot;
+ }
+ if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
+ break;
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_type = btrfs_file_extent_type(leaf, fi);
+
+ if (extent_type == BTRFS_FILE_EXTENT_REG ||
+ extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+ disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ extent_offset = btrfs_file_extent_offset(leaf, fi);
+ extent_end = key.offset +
+ btrfs_file_extent_num_bytes(leaf, fi);
+ } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ extent_end = key.offset +
+ btrfs_file_extent_ram_bytes(leaf, fi);
+ } else {
+ /* can't happen */
+ BUG();
+ }
+
+ /*
+ * Don't skip extent items representing 0 byte lengths. They
+ * used to be created (bug) if while punching holes we hit
+ * -ENOSPC condition. So if we find one here, just ensure we
+ * delete it, otherwise we would insert a new file extent item
+ * with the same key (offset) as that 0 bytes length file
+ * extent item in the call to setup_items_for_insert() later
+ * in this function.
+ */
+ if (extent_end == key.offset && extent_end >= search_start) {
+ last_end = extent_end;
+ goto delete_extent_item;
+ }
+
+ if (extent_end <= search_start) {
+ path->slots[0]++;
+ goto next_slot;
+ }
+
+ found = 1;
+ search_start = max(key.offset, start);
+ if (recow || !modify_tree) {
+ modify_tree = -1;
+ btrfs_release_path(path);
+ continue;
+ }
+
+ /*
+ * | - range to drop - |
+ * | -------- extent -------- |
+ */
+ if (start > key.offset && end < extent_end) {
+ BUG_ON(del_nr > 0);
+ if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
+ memcpy(&new_key, &key, sizeof(new_key));
+ new_key.offset = start;
+ ret = btrfs_duplicate_item(trans, root, path,
+ &new_key);
+ if (ret == -EAGAIN) {
+ btrfs_release_path(path);
+ continue;
+ }
+ if (ret < 0)
+ break;
+
+ leaf = path->nodes[0];
+ fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ start - key.offset);
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+
+ extent_offset += start - key.offset;
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - start);
+ btrfs_mark_buffer_dirty(leaf);
+
+ if (update_refs && disk_bytenr > 0) {
+ ret = btrfs_inc_extent_ref(trans, root,
+ disk_bytenr, num_bytes, 0,
+ root->root_key.objectid,
+ new_key.objectid,
+ start - extent_offset);
+ BUG_ON(ret); /* -ENOMEM */
+ }
+ key.offset = start;
+ }
+ /*
+ * From here on out we will have actually dropped something, so
+ * last_end can be updated.
+ */
+ last_end = extent_end;
+
+ /*
+ * | ---- range to drop ----- |
+ * | -------- extent -------- |
+ */
+ if (start <= key.offset && end < extent_end) {
+ if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
+ memcpy(&new_key, &key, sizeof(new_key));
+ new_key.offset = end;
+ btrfs_set_item_key_safe(fs_info, path, &new_key);
+
+ extent_offset += end - key.offset;
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - end);
+ btrfs_mark_buffer_dirty(leaf);
+ if (update_refs && disk_bytenr > 0)
+ inode_sub_bytes(inode, end - key.offset);
+ break;
+ }
+
+ search_start = extent_end;
+ /*
+ * | ---- range to drop ----- |
+ * | -------- extent -------- |
+ */
+ if (start > key.offset && end >= extent_end) {
+ BUG_ON(del_nr > 0);
+ if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ start - key.offset);
+ btrfs_mark_buffer_dirty(leaf);
+ if (update_refs && disk_bytenr > 0)
+ inode_sub_bytes(inode, extent_end - start);
+ if (end == extent_end)
+ break;
+
+ path->slots[0]++;
+ goto next_slot;
+ }
+
+ /*
+ * | ---- range to drop ----- |
+ * | ------ extent ------ |
+ */
+ if (start <= key.offset && end >= extent_end) {
+delete_extent_item:
+ if (del_nr == 0) {
+ del_slot = path->slots[0];
+ del_nr = 1;
+ } else {
+ BUG_ON(del_slot + del_nr != path->slots[0]);
+ del_nr++;
+ }
+
+ if (update_refs &&
+ extent_type == BTRFS_FILE_EXTENT_INLINE) {
+ inode_sub_bytes(inode,
+ extent_end - key.offset);
+ extent_end = ALIGN(extent_end,
+ fs_info->sectorsize);
+ } else if (update_refs && disk_bytenr > 0) {
+ ret = btrfs_free_extent(trans, root,
+ disk_bytenr, num_bytes, 0,
+ root->root_key.objectid,
+ key.objectid, key.offset -
+ extent_offset);
+ BUG_ON(ret); /* -ENOMEM */
+ inode_sub_bytes(inode,
+ extent_end - key.offset);
+ }
+
+ if (end == extent_end)
+ break;
+
+ if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
+ path->slots[0]++;
+ goto next_slot;
+ }
+
+ ret = btrfs_del_items(trans, root, path, del_slot,
+ del_nr);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ break;
+ }
+
+ del_nr = 0;
+ del_slot = 0;
+
+ btrfs_release_path(path);
+ continue;
+ }
+
+ BUG_ON(1);
+ }
+
+ if (!ret && del_nr > 0) {
+ /*
+ * Set path->slots[0] to first slot, so that after the delete
+ * if items are move off from our leaf to its immediate left or
+ * right neighbor leafs, we end up with a correct and adjusted
+ * path->slots[0] for our insertion (if replace_extent != 0).
+ */
+ path->slots[0] = del_slot;
+ ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+ if (ret)
+ btrfs_abort_transaction(trans, ret);
+ }
+
+ leaf = path->nodes[0];
+ /*
+ * If btrfs_del_items() was called, it might have deleted a leaf, in
+ * which case it unlocked our path, so check path->locks[0] matches a
+ * write lock.
+ */
+ if (!ret && replace_extent && leafs_visited == 1 &&
+ (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
+ path->locks[0] == BTRFS_WRITE_LOCK) &&
+ btrfs_leaf_free_space(fs_info, leaf) >=
+ sizeof(struct btrfs_item) + extent_item_size) {
+
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = start;
+ if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) {
+ struct btrfs_key slot_key;
+
+ btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]);
+ if (btrfs_comp_cpu_keys(&key, &slot_key) > 0)
+ path->slots[0]++;
+ }
+ setup_items_for_insert(root, path, &key,
+ &extent_item_size,
+ extent_item_size,
+ sizeof(struct btrfs_item) +
+ extent_item_size, 1);
+ *key_inserted = 1;
+ }
+
+ if (!replace_extent || !(*key_inserted))
+ btrfs_release_path(path);
+ if (drop_end)
+ *drop_end = found ? min(end, last_end) : end;
+ return ret;
+}
+
+int btrfs_drop_extents(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct inode *inode, u64 start,
+ u64 end, int drop_cache)
+{
+ struct btrfs_path *path;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
+ drop_cache, 0, 0, NULL);
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int extent_mergeable(struct extent_buffer *leaf, int slot,
+ u64 objectid, u64 bytenr, u64 orig_offset,
+ u64 *start, u64 *end)
+{
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ u64 extent_end;
+
+ if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+ return 0;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
+ return 0;
+
+ fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
+ btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
+ btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
+ btrfs_file_extent_compression(leaf, fi) ||
+ btrfs_file_extent_encryption(leaf, fi) ||
+ btrfs_file_extent_other_encoding(leaf, fi))
+ return 0;
+
+ extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+ if ((*start && *start != key.offset) || (*end && *end != extent_end))
+ return 0;
+
+ *start = key.offset;
+ *end = extent_end;
+ return 1;
+}
+
+/*
+ * Mark extent in the range start - end as written.
+ *
+ * This changes extent type from 'pre-allocated' to 'regular'. If only
+ * part of extent is marked as written, the extent will be split into
+ * two or three.
+ */
+int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
+ struct btrfs_inode *inode, u64 start, u64 end)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_root *root = inode->root;
+ struct extent_buffer *leaf;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ struct btrfs_key new_key;
+ u64 bytenr;
+ u64 num_bytes;
+ u64 extent_end;
+ u64 orig_offset;
+ u64 other_start;
+ u64 other_end;
+ u64 split;
+ int del_nr = 0;
+ int del_slot = 0;
+ int recow;
+ int ret;
+ u64 ino = btrfs_ino(inode);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+again:
+ recow = 0;
+ split = start;
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = split;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret < 0)
+ goto out;
+ if (ret > 0 && path->slots[0] > 0)
+ path->slots[0]--;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != ino ||
+ key.type != BTRFS_EXTENT_DATA_KEY) {
+ ret = -EINVAL;
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) {
+ ret = -EINVAL;
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+ if (key.offset > start || extent_end < end) {
+ ret = -EINVAL;
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
+ memcpy(&new_key, &key, sizeof(new_key));
+
+ if (start == key.offset && end < extent_end) {
+ other_start = 0;
+ other_end = start;
+ if (extent_mergeable(leaf, path->slots[0] - 1,
+ ino, bytenr, orig_offset,
+ &other_start, &other_end)) {
+ new_key.offset = end;
+ btrfs_set_item_key_safe(fs_info, path, &new_key);
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi,
+ trans->transid);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - end);
+ btrfs_set_file_extent_offset(leaf, fi,
+ end - orig_offset);
+ fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi,
+ trans->transid);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ end - other_start);
+ btrfs_mark_buffer_dirty(leaf);
+ goto out;
+ }
+ }
+
+ if (start > key.offset && end == extent_end) {
+ other_start = end;
+ other_end = 0;
+ if (extent_mergeable(leaf, path->slots[0] + 1,
+ ino, bytenr, orig_offset,
+ &other_start, &other_end)) {
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ start - key.offset);
+ btrfs_set_file_extent_generation(leaf, fi,
+ trans->transid);
+ path->slots[0]++;
+ new_key.offset = start;
+ btrfs_set_item_key_safe(fs_info, path, &new_key);
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi,
+ trans->transid);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ other_end - start);
+ btrfs_set_file_extent_offset(leaf, fi,
+ start - orig_offset);
+ btrfs_mark_buffer_dirty(leaf);
+ goto out;
+ }
+ }
+
+ while (start > key.offset || end < extent_end) {
+ if (key.offset == start)
+ split = end;
+
+ new_key.offset = split;
+ ret = btrfs_duplicate_item(trans, root, path, &new_key);
+ if (ret == -EAGAIN) {
+ btrfs_release_path(path);
+ goto again;
+ }
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ split - key.offset);
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+
+ btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+ btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - split);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
+ 0, root->root_key.objectid,
+ ino, orig_offset);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+
+ if (split == start) {
+ key.offset = start;
+ } else {
+ if (start != key.offset) {
+ ret = -EINVAL;
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ path->slots[0]--;
+ extent_end = end;
+ }
+ recow = 1;
+ }
+
+ other_start = end;
+ other_end = 0;
+ if (extent_mergeable(leaf, path->slots[0] + 1,
+ ino, bytenr, orig_offset,
+ &other_start, &other_end)) {
+ if (recow) {
+ btrfs_release_path(path);
+ goto again;
+ }
+ extent_end = other_end;
+ del_slot = path->slots[0] + 1;
+ del_nr++;
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ 0, root->root_key.objectid,
+ ino, orig_offset);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+ other_start = 0;
+ other_end = start;
+ if (extent_mergeable(leaf, path->slots[0] - 1,
+ ino, bytenr, orig_offset,
+ &other_start, &other_end)) {
+ if (recow) {
+ btrfs_release_path(path);
+ goto again;
+ }
+ key.offset = other_start;
+ del_slot = path->slots[0];
+ del_nr++;
+ ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+ 0, root->root_key.objectid,
+ ino, orig_offset);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+ if (del_nr == 0) {
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_type(leaf, fi,
+ BTRFS_FILE_EXTENT_REG);
+ btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+ btrfs_mark_buffer_dirty(leaf);
+ } else {
+ fi = btrfs_item_ptr(leaf, del_slot - 1,
+ struct btrfs_file_extent_item);
+ btrfs_set_file_extent_type(leaf, fi,
+ BTRFS_FILE_EXTENT_REG);
+ btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+ btrfs_set_file_extent_num_bytes(leaf, fi,
+ extent_end - key.offset);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+out:
+ btrfs_free_path(path);
+ return 0;
+}
+
+/*
+ * on error we return an unlocked page and the error value
+ * on success we return a locked page and 0
+ */
+static int prepare_uptodate_page(struct inode *inode,
+ struct page *page, u64 pos,
+ bool force_uptodate)
+{
+ int ret = 0;
+
+ if (((pos & (PAGE_SIZE - 1)) || force_uptodate) &&
+ !PageUptodate(page)) {
+ ret = btrfs_readpage(NULL, page);
+ if (ret)
+ return ret;
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ unlock_page(page);
+ return -EIO;
+ }
+ if (page->mapping != inode->i_mapping) {
+ unlock_page(page);
+ return -EAGAIN;
+ }
+ }
+ return 0;
+}
+
+/*
+ * this just gets pages into the page cache and locks them down.
+ */
+static noinline int prepare_pages(struct inode *inode, struct page **pages,
+ size_t num_pages, loff_t pos,
+ size_t write_bytes, bool force_uptodate)
+{
+ int i;
+ unsigned long index = pos >> PAGE_SHIFT;
+ gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
+ int err = 0;
+ int faili;
+
+ for (i = 0; i < num_pages; i++) {
+again:
+ pages[i] = find_or_create_page(inode->i_mapping, index + i,
+ mask | __GFP_WRITE);
+ if (!pages[i]) {
+ faili = i - 1;
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ if (i == 0)
+ err = prepare_uptodate_page(inode, pages[i], pos,
+ force_uptodate);
+ if (!err && i == num_pages - 1)
+ err = prepare_uptodate_page(inode, pages[i],
+ pos + write_bytes, false);
+ if (err) {
+ put_page(pages[i]);
+ if (err == -EAGAIN) {
+ err = 0;
+ goto again;
+ }
+ faili = i - 1;
+ goto fail;
+ }
+ wait_on_page_writeback(pages[i]);
+ }
+
+ return 0;
+fail:
+ while (faili >= 0) {
+ unlock_page(pages[faili]);
+ put_page(pages[faili]);
+ faili--;
+ }
+ return err;
+
+}
+
+/*
+ * This function locks the extent and properly waits for data=ordered extents
+ * to finish before allowing the pages to be modified if need.
+ *
+ * The return value:
+ * 1 - the extent is locked
+ * 0 - the extent is not locked, and everything is OK
+ * -EAGAIN - need re-prepare the pages
+ * the other < 0 number - Something wrong happens
+ */
+static noinline int
+lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
+ size_t num_pages, loff_t pos,
+ size_t write_bytes,
+ u64 *lockstart, u64 *lockend,
+ struct extent_state **cached_state)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ u64 start_pos;
+ u64 last_pos;
+ int i;
+ int ret = 0;
+
+ start_pos = round_down(pos, fs_info->sectorsize);
+ last_pos = start_pos
+ + round_up(pos + write_bytes - start_pos,
+ fs_info->sectorsize) - 1;
+
+ if (start_pos < inode->vfs_inode.i_size) {
+ struct btrfs_ordered_extent *ordered;
+
+ lock_extent_bits(&inode->io_tree, start_pos, last_pos,
+ cached_state);
+ ordered = btrfs_lookup_ordered_range(inode, start_pos,
+ last_pos - start_pos + 1);
+ if (ordered &&
+ ordered->file_offset + ordered->len > start_pos &&
+ ordered->file_offset <= last_pos) {
+ unlock_extent_cached(&inode->io_tree, start_pos,
+ last_pos, cached_state);
+ for (i = 0; i < num_pages; i++) {
+ unlock_page(pages[i]);
+ put_page(pages[i]);
+ }
+ btrfs_start_ordered_extent(&inode->vfs_inode,
+ ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ return -EAGAIN;
+ }
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+
+ *lockstart = start_pos;
+ *lockend = last_pos;
+ ret = 1;
+ }
+
+ /*
+ * It's possible the pages are dirty right now, but we don't want
+ * to clean them yet because copy_from_user may catch a page fault
+ * and we might have to fall back to one page at a time. If that
+ * happens, we'll unlock these pages and we'd have a window where
+ * reclaim could sneak in and drop the once-dirty page on the floor
+ * without writing it.
+ *
+ * We have the pages locked and the extent range locked, so there's
+ * no way someone can start IO on any dirty pages in this range.
+ *
+ * We'll call btrfs_dirty_pages() later on, and that will flip around
+ * delalloc bits and dirty the pages as required.
+ */
+ for (i = 0; i < num_pages; i++) {
+ set_page_extent_mapped(pages[i]);
+ WARN_ON(!PageLocked(pages[i]));
+ }
+
+ return ret;
+}
+
+static noinline int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
+ size_t *write_bytes)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct btrfs_root *root = inode->root;
+ struct btrfs_ordered_extent *ordered;
+ u64 lockstart, lockend;
+ u64 num_bytes;
+ int ret;
+
+ ret = btrfs_start_write_no_snapshotting(root);
+ if (!ret)
+ return -ENOSPC;
+
+ lockstart = round_down(pos, fs_info->sectorsize);
+ lockend = round_up(pos + *write_bytes,
+ fs_info->sectorsize) - 1;
+
+ while (1) {
+ lock_extent(&inode->io_tree, lockstart, lockend);
+ ordered = btrfs_lookup_ordered_range(inode, lockstart,
+ lockend - lockstart + 1);
+ if (!ordered) {
+ break;
+ }
+ unlock_extent(&inode->io_tree, lockstart, lockend);
+ btrfs_start_ordered_extent(&inode->vfs_inode, ordered, 1);
+ btrfs_put_ordered_extent(ordered);
+ }
+
+ num_bytes = lockend - lockstart + 1;
+ ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes,
+ NULL, NULL, NULL);
+ if (ret <= 0) {
+ ret = 0;
+ btrfs_end_write_no_snapshotting(root);
+ } else {
+ *write_bytes = min_t(size_t, *write_bytes ,
+ num_bytes - pos + lockstart);
+ }
+
+ unlock_extent(&inode->io_tree, lockstart, lockend);
+
+ return ret;
+}
+
+static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
+ struct iov_iter *i)
+{
+ struct file *file = iocb->ki_filp;
+ loff_t pos = iocb->ki_pos;
+ struct inode *inode = file_inode(file);
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct page **pages = NULL;
+ struct extent_state *cached_state = NULL;
+ struct extent_changeset *data_reserved = NULL;
+ u64 release_bytes = 0;
+ u64 lockstart;
+ u64 lockend;
+ size_t num_written = 0;
+ int nrptrs;
+ int ret = 0;
+ bool only_release_metadata = false;
+ bool force_page_uptodate = false;
+
+ nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
+ PAGE_SIZE / (sizeof(struct page *)));
+ nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
+ nrptrs = max(nrptrs, 8);
+ pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
+ if (!pages)
+ return -ENOMEM;
+
+ while (iov_iter_count(i) > 0) {
+ size_t offset = pos & (PAGE_SIZE - 1);
+ size_t sector_offset;
+ size_t write_bytes = min(iov_iter_count(i),
+ nrptrs * (size_t)PAGE_SIZE -
+ offset);
+ size_t num_pages = DIV_ROUND_UP(write_bytes + offset,
+ PAGE_SIZE);
+ size_t reserve_bytes;
+ size_t dirty_pages;
+ size_t copied;
+ size_t dirty_sectors;
+ size_t num_sectors;
+ int extents_locked;
+
+ WARN_ON(num_pages > nrptrs);
+
+ /*
+ * Fault pages before locking them in prepare_pages
+ * to avoid recursive lock
+ */
+ if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ sector_offset = pos & (fs_info->sectorsize - 1);
+ reserve_bytes = round_up(write_bytes + sector_offset,
+ fs_info->sectorsize);
+
+ extent_changeset_release(data_reserved);
+ ret = btrfs_check_data_free_space(inode, &data_reserved, pos,
+ write_bytes);
+ if (ret < 0) {
+ if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
+ BTRFS_INODE_PREALLOC)) &&
+ check_can_nocow(BTRFS_I(inode), pos,
+ &write_bytes) > 0) {
+ /*
+ * For nodata cow case, no need to reserve
+ * data space.
+ */
+ only_release_metadata = true;
+ /*
+ * our prealloc extent may be smaller than
+ * write_bytes, so scale down.
+ */
+ num_pages = DIV_ROUND_UP(write_bytes + offset,
+ PAGE_SIZE);
+ reserve_bytes = round_up(write_bytes +
+ sector_offset,
+ fs_info->sectorsize);
+ } else {
+ break;
+ }
+ }
+
+ WARN_ON(reserve_bytes == 0);
+ ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
+ reserve_bytes);
+ if (ret) {
+ if (!only_release_metadata)
+ btrfs_free_reserved_data_space(inode,
+ data_reserved, pos,
+ write_bytes);
+ else
+ btrfs_end_write_no_snapshotting(root);
+ break;
+ }
+
+ release_bytes = reserve_bytes;
+again:
+ /*
+ * This is going to setup the pages array with the number of
+ * pages we want, so we don't really need to worry about the
+ * contents of pages from loop to loop
+ */
+ ret = prepare_pages(inode, pages, num_pages,
+ pos, write_bytes,
+ force_page_uptodate);
+ if (ret) {
+ btrfs_delalloc_release_extents(BTRFS_I(inode),
+ reserve_bytes, true);
+ break;
+ }
+
+ extents_locked = lock_and_cleanup_extent_if_need(
+ BTRFS_I(inode), pages,
+ num_pages, pos, write_bytes, &lockstart,
+ &lockend, &cached_state);
+ if (extents_locked < 0) {
+ if (extents_locked == -EAGAIN)
+ goto again;
+ btrfs_delalloc_release_extents(BTRFS_I(inode),
+ reserve_bytes, true);
+ ret = extents_locked;
+ break;
+ }
+
+ copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
+
+ num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
+ dirty_sectors = round_up(copied + sector_offset,
+ fs_info->sectorsize);
+ dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors);
+
+ /*
+ * if we have trouble faulting in the pages, fall
+ * back to one page at a time
+ */
+ if (copied < write_bytes)
+ nrptrs = 1;
+
+ if (copied == 0) {
+ force_page_uptodate = true;
+ dirty_sectors = 0;
+ dirty_pages = 0;
+ } else {
+ force_page_uptodate = false;
+ dirty_pages = DIV_ROUND_UP(copied + offset,
+ PAGE_SIZE);
+ }
+
+ if (num_sectors > dirty_sectors) {
+ /* release everything except the sectors we dirtied */
+ release_bytes -= dirty_sectors <<
+ fs_info->sb->s_blocksize_bits;
+ if (only_release_metadata) {
+ btrfs_delalloc_release_metadata(BTRFS_I(inode),
+ release_bytes, true);
+ } else {
+ u64 __pos;
+
+ __pos = round_down(pos,
+ fs_info->sectorsize) +
+ (dirty_pages << PAGE_SHIFT);
+ btrfs_delalloc_release_space(inode,
+ data_reserved, __pos,
+ release_bytes, true);
+ }
+ }
+
+ release_bytes = round_up(copied + sector_offset,
+ fs_info->sectorsize);
+
+ if (copied > 0)
+ ret = btrfs_dirty_pages(inode, pages, dirty_pages,
+ pos, copied, &cached_state);
+ if (extents_locked)
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+ lockstart, lockend, &cached_state);
+ btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes,
+ true);
+ if (ret) {
+ btrfs_drop_pages(pages, num_pages);
+ break;
+ }
+
+ release_bytes = 0;
+ if (only_release_metadata)
+ btrfs_end_write_no_snapshotting(root);
+
+ if (only_release_metadata && copied > 0) {
+ lockstart = round_down(pos,
+ fs_info->sectorsize);
+ lockend = round_up(pos + copied,
+ fs_info->sectorsize) - 1;
+
+ set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
+ lockend, EXTENT_NORESERVE, NULL,
+ NULL, GFP_NOFS);
+ only_release_metadata = false;
+ }
+
+ btrfs_drop_pages(pages, num_pages);
+
+ cond_resched();
+
+ balance_dirty_pages_ratelimited(inode->i_mapping);
+ if (dirty_pages < (fs_info->nodesize >> PAGE_SHIFT) + 1)
+ btrfs_btree_balance_dirty(fs_info);
+
+ pos += copied;
+ num_written += copied;
+ }
+
+ kfree(pages);
+
+ if (release_bytes) {
+ if (only_release_metadata) {
+ btrfs_end_write_no_snapshotting(root);
+ btrfs_delalloc_release_metadata(BTRFS_I(inode),
+ release_bytes, true);
+ } else {
+ btrfs_delalloc_release_space(inode, data_reserved,
+ round_down(pos, fs_info->sectorsize),
+ release_bytes, true);
+ }
+ }
+
+ extent_changeset_free(data_reserved);
+ return num_written ? num_written : ret;
+}
+
+static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file_inode(file);
+ loff_t pos;
+ ssize_t written;
+ ssize_t written_buffered;
+ loff_t endbyte;
+ int err;
+
+ written = generic_file_direct_write(iocb, from);
+
+ if (written < 0 || !iov_iter_count(from))
+ return written;
+
+ pos = iocb->ki_pos;
+ written_buffered = btrfs_buffered_write(iocb, from);
+ if (written_buffered < 0) {
+ err = written_buffered;
+ goto out;
+ }
+ /*
+ * Ensure all data is persisted. We want the next direct IO read to be
+ * able to read what was just written.
+ */
+ endbyte = pos + written_buffered - 1;
+ err = btrfs_fdatawrite_range(inode, pos, endbyte);
+ if (err)
+ goto out;
+ err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte);
+ if (err)
+ goto out;
+ written += written_buffered;
+ iocb->ki_pos = pos + written_buffered;
+ invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT,
+ endbyte >> PAGE_SHIFT);
+out:
+ return written ? written : err;
+}
+
+static void update_time_for_write(struct inode *inode)
+{
+ struct timespec64 now;
+
+ if (IS_NOCMTIME(inode))
+ return;
+
+ now = current_time(inode);
+ if (!timespec64_equal(&inode->i_mtime, &now))
+ inode->i_mtime = now;
+
+ if (!timespec64_equal(&inode->i_ctime, &now))
+ inode->i_ctime = now;
+
+ if (IS_I_VERSION(inode))
+ inode_inc_iversion(inode);
+}
+
+static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
+ struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file_inode(file);
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ u64 start_pos;
+ u64 end_pos;
+ ssize_t num_written = 0;
+ bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
+ ssize_t err;
+ loff_t pos;
+ size_t count = iov_iter_count(from);
+ loff_t oldsize;
+ int clean_page = 0;
+
+ if (!(iocb->ki_flags & IOCB_DIRECT) &&
+ (iocb->ki_flags & IOCB_NOWAIT))
+ return -EOPNOTSUPP;
+
+ if (!inode_trylock(inode)) {
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+ inode_lock(inode);
+ }
+
+ err = generic_write_checks(iocb, from);
+ if (err <= 0) {
+ inode_unlock(inode);
+ return err;
+ }
+
+ pos = iocb->ki_pos;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ /*
+ * We will allocate space in case nodatacow is not set,
+ * so bail
+ */
+ if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
+ BTRFS_INODE_PREALLOC)) ||
+ check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) {
+ inode_unlock(inode);
+ return -EAGAIN;
+ }
+ }
+
+ current->backing_dev_info = inode_to_bdi(inode);
+ err = file_remove_privs(file);
+ if (err) {
+ inode_unlock(inode);
+ goto out;
+ }
+
+ /*
+ * If BTRFS flips readonly due to some impossible error
+ * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
+ * although we have opened a file as writable, we have
+ * to stop this write operation to ensure FS consistency.
+ */
+ if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
+ inode_unlock(inode);
+ err = -EROFS;
+ goto out;
+ }
+
+ /*
+ * We reserve space for updating the inode when we reserve space for the
+ * extent we are going to write, so we will enospc out there. We don't
+ * need to start yet another transaction to update the inode as we will
+ * update the inode when we finish writing whatever data we write.
+ */
+ update_time_for_write(inode);
+
+ start_pos = round_down(pos, fs_info->sectorsize);
+ oldsize = i_size_read(inode);
+ if (start_pos > oldsize) {
+ /* Expand hole size to cover write data, preventing empty gap */
+ end_pos = round_up(pos + count,
+ fs_info->sectorsize);
+ err = btrfs_cont_expand(inode, oldsize, end_pos);
+ if (err) {
+ inode_unlock(inode);
+ goto out;
+ }
+ if (start_pos > round_up(oldsize, fs_info->sectorsize))
+ clean_page = 1;
+ }
+
+ if (sync)
+ atomic_inc(&BTRFS_I(inode)->sync_writers);
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ num_written = __btrfs_direct_write(iocb, from);
+ } else {
+ num_written = btrfs_buffered_write(iocb, from);
+ if (num_written > 0)
+ iocb->ki_pos = pos + num_written;
+ if (clean_page)
+ pagecache_isize_extended(inode, oldsize,
+ i_size_read(inode));
+ }
+
+ inode_unlock(inode);
+
+ /*
+ * We also have to set last_sub_trans to the current log transid,
+ * otherwise subsequent syncs to a file that's been synced in this
+ * transaction will appear to have already occurred.
+ */
+ spin_lock(&BTRFS_I(inode)->lock);
+ BTRFS_I(inode)->last_sub_trans = root->log_transid;
+ spin_unlock(&BTRFS_I(inode)->lock);
+ if (num_written > 0)
+ num_written = generic_write_sync(iocb, num_written);
+
+ if (sync)
+ atomic_dec(&BTRFS_I(inode)->sync_writers);
+out:
+ current->backing_dev_info = NULL;
+ return num_written ? num_written : err;
+}
+
+int btrfs_release_file(struct inode *inode, struct file *filp)
+{
+ struct btrfs_file_private *private = filp->private_data;
+
+ if (private && private->filldir_buf)
+ kfree(private->filldir_buf);
+ kfree(private);
+ filp->private_data = NULL;
+
+ /*
+ * ordered_data_close is set by settattr when we are about to truncate
+ * a file from a non-zero size to a zero size. This tries to
+ * flush down new bytes that may have been written if the
+ * application were using truncate to replace a file in place.
+ */
+ if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
+ &BTRFS_I(inode)->runtime_flags))
+ filemap_flush(inode->i_mapping);
+ return 0;
+}
+
+static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end)
+{
+ int ret;
+ struct blk_plug plug;
+
+ /*
+ * This is only called in fsync, which would do synchronous writes, so
+ * a plug can merge adjacent IOs as much as possible. Esp. in case of
+ * multiple disks using raid profile, a large IO can be split to
+ * several segments of stripe length (currently 64K).
+ */
+ blk_start_plug(&plug);
+ atomic_inc(&BTRFS_I(inode)->sync_writers);
+ ret = btrfs_fdatawrite_range(inode, start, end);
+ atomic_dec(&BTRFS_I(inode)->sync_writers);
+ blk_finish_plug(&plug);
+
+ return ret;
+}
+
+/*
+ * fsync call for both files and directories. This logs the inode into
+ * the tree log instead of forcing full commits whenever possible.
+ *
+ * It needs to call filemap_fdatawait so that all ordered extent updates are
+ * in the metadata btree are up to date for copying to the log.
+ *
+ * It drops the inode mutex before doing the tree log commit. This is an
+ * important optimization for directories because holding the mutex prevents
+ * new operations on the dir while we write to disk.
+ */
+int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ struct dentry *dentry = file_dentry(file);
+ struct inode *inode = d_inode(dentry);
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_log_ctx ctx;
+ int ret = 0, err;
+ u64 len;
+
+ /*
+ * The range length can be represented by u64, we have to do the typecasts
+ * to avoid signed overflow if it's [0, LLONG_MAX] eg. from fsync()
+ */
+ len = (u64)end - (u64)start + 1;
+ trace_btrfs_sync_file(file, datasync);
+
+ btrfs_init_log_ctx(&ctx, inode);
+
+ /*
+ * We write the dirty pages in the range and wait until they complete
+ * out of the ->i_mutex. If so, we can flush the dirty pages by
+ * multi-task, and make the performance up. See
+ * btrfs_wait_ordered_range for an explanation of the ASYNC check.
+ */
+ ret = start_ordered_ops(inode, start, end);
+ if (ret)
+ goto out;
+
+ inode_lock(inode);
+
+ /*
+ * We take the dio_sem here because the tree log stuff can race with
+ * lockless dio writes and get an extent map logged for an extent we
+ * never waited on. We need it this high up for lockdep reasons.
+ */
+ down_write(&BTRFS_I(inode)->dio_sem);
+
+ atomic_inc(&root->log_batch);
+
+ /*
+ * Before we acquired the inode's lock, someone may have dirtied more
+ * pages in the target range. We need to make sure that writeback for
+ * any such pages does not start while we are logging the inode, because
+ * if it does, any of the following might happen when we are not doing a
+ * full inode sync:
+ *
+ * 1) We log an extent after its writeback finishes but before its
+ * checksums are added to the csum tree, leading to -EIO errors
+ * when attempting to read the extent after a log replay.
+ *
+ * 2) We can end up logging an extent before its writeback finishes.
+ * Therefore after the log replay we will have a file extent item
+ * pointing to an unwritten extent (and no data checksums as well).
+ *
+ * So trigger writeback for any eventual new dirty pages and then we
+ * wait for all ordered extents to complete below.
+ */
+ ret = start_ordered_ops(inode, start, end);
+ if (ret) {
+ inode_unlock(inode);
+ goto out;
+ }
+
+ /*
+ * We have to do this here to avoid the priority inversion of waiting on
+ * IO of a lower priority task while holding a transaciton open.
+ */
+ ret = btrfs_wait_ordered_range(inode, start, len);
+ if (ret) {
+ up_write(&BTRFS_I(inode)->dio_sem);
+ inode_unlock(inode);
+ goto out;
+ }
+ atomic_inc(&root->log_batch);
+
+ smp_mb();
+ if (btrfs_inode_in_log(BTRFS_I(inode), fs_info->generation) ||
+ BTRFS_I(inode)->last_trans <= fs_info->last_trans_committed) {
+ /*
+ * We've had everything committed since the last time we were
+ * modified so clear this flag in case it was set for whatever
+ * reason, it's no longer relevant.
+ */
+ clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &BTRFS_I(inode)->runtime_flags);
+ /*
+ * An ordered extent might have started before and completed
+ * already with io errors, in which case the inode was not
+ * updated and we end up here. So check the inode's mapping
+ * for any errors that might have happened since we last
+ * checked called fsync.
+ */
+ ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err);
+ up_write(&BTRFS_I(inode)->dio_sem);
+ inode_unlock(inode);
+ goto out;
+ }
+
+ /*
+ * We use start here because we will need to wait on the IO to complete
+ * in btrfs_sync_log, which could require joining a transaction (for
+ * example checking cross references in the nocow path). If we use join
+ * here we could get into a situation where we're waiting on IO to
+ * happen that is blocked on a transaction trying to commit. With start
+ * we inc the extwriter counter, so we wait for all extwriters to exit
+ * before we start blocking join'ers. This comment is to keep somebody
+ * from thinking they are super smart and changing this to
+ * btrfs_join_transaction *cough*Josef*cough*.
+ */
+ trans = btrfs_start_transaction(root, 0);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ up_write(&BTRFS_I(inode)->dio_sem);
+ inode_unlock(inode);
+ goto out;
+ }
+ trans->sync = true;
+
+ ret = btrfs_log_dentry_safe(trans, dentry, start, end, &ctx);
+ if (ret < 0) {
+ /* Fallthrough and commit/free transaction. */
+ ret = 1;
+ }
+
+ /* we've logged all the items and now have a consistent
+ * version of the file in the log. It is possible that
+ * someone will come in and modify the file, but that's
+ * fine because the log is consistent on disk, and we
+ * have references to all of the file's extents
+ *
+ * It is possible that someone will come in and log the
+ * file again, but that will end up using the synchronization
+ * inside btrfs_sync_log to keep things safe.
+ */
+ up_write(&BTRFS_I(inode)->dio_sem);
+ inode_unlock(inode);
+
+ /*
+ * If any of the ordered extents had an error, just return it to user
+ * space, so that the application knows some writes didn't succeed and
+ * can take proper action (retry for e.g.). Blindly committing the
+ * transaction in this case, would fool userspace that everything was
+ * successful. And we also want to make sure our log doesn't contain
+ * file extent items pointing to extents that weren't fully written to -
+ * just like in the non fast fsync path, where we check for the ordered
+ * operation's error flag before writing to the log tree and return -EIO
+ * if any of them had this flag set (btrfs_wait_ordered_range) -
+ * therefore we need to check for errors in the ordered operations,
+ * which are indicated by ctx.io_err.
+ */
+ if (ctx.io_err) {
+ btrfs_end_transaction(trans);
+ ret = ctx.io_err;
+ goto out;
+ }
+
+ if (ret != BTRFS_NO_LOG_SYNC) {
+ if (!ret) {
+ ret = btrfs_sync_log(trans, root, &ctx);
+ if (!ret) {
+ ret = btrfs_end_transaction(trans);
+ goto out;
+ }
+ }
+ ret = btrfs_commit_transaction(trans);
+ } else {
+ ret = btrfs_end_transaction(trans);
+ }
+out:
+ ASSERT(list_empty(&ctx.list));
+ err = file_check_and_advance_wb_err(file);
+ if (!ret)
+ ret = err;
+ return ret > 0 ? -EIO : ret;
+}
+
+static const struct vm_operations_struct btrfs_file_vm_ops = {
+ .fault = filemap_fault,
+ .map_pages = filemap_map_pages,
+ .page_mkwrite = btrfs_page_mkwrite,
+};
+
+static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct address_space *mapping = filp->f_mapping;
+
+ if (!mapping->a_ops->readpage)
+ return -ENOEXEC;
+
+ file_accessed(filp);
+ vma->vm_ops = &btrfs_file_vm_ops;
+
+ return 0;
+}
+
+static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf,
+ int slot, u64 start, u64 end)
+{
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+
+ if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+ return 0;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != btrfs_ino(inode) ||
+ key.type != BTRFS_EXTENT_DATA_KEY)
+ return 0;
+
+ fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+
+ if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
+ return 0;
+
+ if (btrfs_file_extent_disk_bytenr(leaf, fi))
+ return 0;
+
+ if (key.offset == end)
+ return 1;
+ if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
+ return 1;
+ return 0;
+}
+
+static int fill_holes(struct btrfs_trans_handle *trans,
+ struct btrfs_inode *inode,
+ struct btrfs_path *path, u64 offset, u64 end)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_root *root = inode->root;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *fi;
+ struct extent_map *hole_em;
+ struct extent_map_tree *em_tree = &inode->extent_tree;
+ struct btrfs_key key;
+ int ret;
+
+ if (btrfs_fs_incompat(fs_info, NO_HOLES))
+ goto out;
+
+ key.objectid = btrfs_ino(inode);
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = offset;
+
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+ if (ret <= 0) {
+ /*
+ * We should have dropped this offset, so if we find it then
+ * something has gone horribly wrong.
+ */
+ if (ret == 0)
+ ret = -EINVAL;
+ return ret;
+ }
+
+ leaf = path->nodes[0];
+ if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) {
+ u64 num_bytes;
+
+ path->slots[0]--;
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
+ end - offset;
+ btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_offset(leaf, fi, 0);
+ btrfs_mark_buffer_dirty(leaf);
+ goto out;
+ }
+
+ if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) {
+ u64 num_bytes;
+
+ key.offset = offset;
+ btrfs_set_item_key_safe(fs_info, path, &key);
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
+ offset;
+ btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+ btrfs_set_file_extent_offset(leaf, fi, 0);
+ btrfs_mark_buffer_dirty(leaf);
+ goto out;
+ }
+ btrfs_release_path(path);
+
+ ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode),
+ offset, 0, 0, end - offset, 0, end - offset, 0, 0, 0);
+ if (ret)
+ return ret;
+
+out:
+ btrfs_release_path(path);
+
+ hole_em = alloc_extent_map();
+ if (!hole_em) {
+ btrfs_drop_extent_cache(inode, offset, end - 1, 0);
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags);
+ } else {
+ hole_em->start = offset;
+ hole_em->len = end - offset;
+ hole_em->ram_bytes = hole_em->len;
+ hole_em->orig_start = offset;
+
+ hole_em->block_start = EXTENT_MAP_HOLE;
+ hole_em->block_len = 0;
+ hole_em->orig_block_len = 0;
+ hole_em->bdev = fs_info->fs_devices->latest_bdev;
+ hole_em->compress_type = BTRFS_COMPRESS_NONE;
+ hole_em->generation = trans->transid;
+
+ do {
+ btrfs_drop_extent_cache(inode, offset, end - 1, 0);
+ write_lock(&em_tree->lock);
+ ret = add_extent_mapping(em_tree, hole_em, 1);
+ write_unlock(&em_tree->lock);
+ } while (ret == -EEXIST);
+ free_extent_map(hole_em);
+ if (ret)
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &inode->runtime_flags);
+ }
+
+ return 0;
+}
+
+/*
+ * Find a hole extent on given inode and change start/len to the end of hole
+ * extent.(hole/vacuum extent whose em->start <= start &&
+ * em->start + em->len > start)
+ * When a hole extent is found, return 1 and modify start/len.
+ */
+static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct extent_map *em;
+ int ret = 0;
+
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
+ round_down(*start, fs_info->sectorsize),
+ round_up(*len, fs_info->sectorsize), 0);
+ if (IS_ERR(em))
+ return PTR_ERR(em);
+
+ /* Hole or vacuum extent(only exists in no-hole mode) */
+ if (em->block_start == EXTENT_MAP_HOLE) {
+ ret = 1;
+ *len = em->start + em->len > *start + *len ?
+ 0 : *start + *len - em->start - em->len;
+ *start = em->start + em->len;
+ }
+ free_extent_map(em);
+ return ret;
+}
+
+static int btrfs_punch_hole_lock_range(struct inode *inode,
+ const u64 lockstart,
+ const u64 lockend,
+ struct extent_state **cached_state)
+{
+ while (1) {
+ struct btrfs_ordered_extent *ordered;
+ int ret;
+
+ truncate_pagecache_range(inode, lockstart, lockend);
+
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ cached_state);
+ ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
+
+ /*
+ * We need to make sure we have no ordered extents in this range
+ * and nobody raced in and read a page in this range, if we did
+ * we need to try again.
+ */
+ if ((!ordered ||
+ (ordered->file_offset + ordered->len <= lockstart ||
+ ordered->file_offset > lockend)) &&
+ !filemap_range_has_page(inode->i_mapping,
+ lockstart, lockend)) {
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ break;
+ }
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
+ lockend, cached_state);
+ ret = btrfs_wait_ordered_range(inode, lockstart,
+ lockend - lockstart + 1);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
+static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_state *cached_state = NULL;
+ struct btrfs_path *path;
+ struct btrfs_block_rsv *rsv;
+ struct btrfs_trans_handle *trans;
+ u64 lockstart;
+ u64 lockend;
+ u64 tail_start;
+ u64 tail_len;
+ u64 orig_start = offset;
+ u64 cur_offset;
+ u64 min_size = btrfs_calc_trans_metadata_size(fs_info, 1);
+ u64 drop_end;
+ int ret = 0;
+ int err = 0;
+ unsigned int rsv_count;
+ bool same_block;
+ bool no_holes = btrfs_fs_incompat(fs_info, NO_HOLES);
+ u64 ino_size;
+ bool truncated_block = false;
+ bool updated_inode = false;
+
+ ret = btrfs_wait_ordered_range(inode, offset, len);
+ if (ret)
+ return ret;
+
+ inode_lock(inode);
+ ino_size = round_up(inode->i_size, fs_info->sectorsize);
+ ret = find_first_non_hole(inode, &offset, &len);
+ if (ret < 0)
+ goto out_only_mutex;
+ if (ret && !len) {
+ /* Already in a large hole */
+ ret = 0;
+ goto out_only_mutex;
+ }
+
+ lockstart = round_up(offset, btrfs_inode_sectorsize(inode));
+ lockend = round_down(offset + len,
+ btrfs_inode_sectorsize(inode)) - 1;
+ same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset))
+ == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1));
+ /*
+ * We needn't truncate any block which is beyond the end of the file
+ * because we are sure there is no data there.
+ */
+ /*
+ * Only do this if we are in the same block and we aren't doing the
+ * entire block.
+ */
+ if (same_block && len < fs_info->sectorsize) {
+ if (offset < ino_size) {
+ truncated_block = true;
+ ret = btrfs_truncate_block(inode, offset, len, 0);
+ } else {
+ ret = 0;
+ }
+ goto out_only_mutex;
+ }
+
+ /* zero back part of the first block */
+ if (offset < ino_size) {
+ truncated_block = true;
+ ret = btrfs_truncate_block(inode, offset, 0, 0);
+ if (ret) {
+ inode_unlock(inode);
+ return ret;
+ }
+ }
+
+ /* Check the aligned pages after the first unaligned page,
+ * if offset != orig_start, which means the first unaligned page
+ * including several following pages are already in holes,
+ * the extra check can be skipped */
+ if (offset == orig_start) {
+ /* after truncate page, check hole again */
+ len = offset + len - lockstart;
+ offset = lockstart;
+ ret = find_first_non_hole(inode, &offset, &len);
+ if (ret < 0)
+ goto out_only_mutex;
+ if (ret && !len) {
+ ret = 0;
+ goto out_only_mutex;
+ }
+ lockstart = offset;
+ }
+
+ /* Check the tail unaligned part is in a hole */
+ tail_start = lockend + 1;
+ tail_len = offset + len - tail_start;
+ if (tail_len) {
+ ret = find_first_non_hole(inode, &tail_start, &tail_len);
+ if (unlikely(ret < 0))
+ goto out_only_mutex;
+ if (!ret) {
+ /* zero the front end of the last page */
+ if (tail_start + tail_len < ino_size) {
+ truncated_block = true;
+ ret = btrfs_truncate_block(inode,
+ tail_start + tail_len,
+ 0, 1);
+ if (ret)
+ goto out_only_mutex;
+ }
+ }
+ }
+
+ if (lockend < lockstart) {
+ ret = 0;
+ goto out_only_mutex;
+ }
+
+ ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
+ &cached_state);
+ if (ret) {
+ inode_unlock(inode);
+ goto out_only_mutex;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
+ if (!rsv) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+ rsv->size = btrfs_calc_trans_metadata_size(fs_info, 1);
+ rsv->failfast = 1;
+
+ /*
+ * 1 - update the inode
+ * 1 - removing the extents in the range
+ * 1 - adding the hole extent if no_holes isn't set
+ */
+ rsv_count = no_holes ? 2 : 3;
+ trans = btrfs_start_transaction(root, rsv_count);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+
+ ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
+ min_size, 0);
+ BUG_ON(ret);
+ trans->block_rsv = rsv;
+
+ cur_offset = lockstart;
+ len = lockend - cur_offset;
+ while (cur_offset < lockend) {
+ ret = __btrfs_drop_extents(trans, root, inode, path,
+ cur_offset, lockend + 1,
+ &drop_end, 1, 0, 0, NULL);
+ if (ret != -ENOSPC)
+ break;
+
+ trans->block_rsv = &fs_info->trans_block_rsv;
+
+ if (cur_offset < drop_end && cur_offset < ino_size) {
+ ret = fill_holes(trans, BTRFS_I(inode), path,
+ cur_offset, drop_end);
+ if (ret) {
+ /*
+ * If we failed then we didn't insert our hole
+ * entries for the area we dropped, so now the
+ * fs is corrupted, so we must abort the
+ * transaction.
+ */
+ btrfs_abort_transaction(trans, ret);
+ err = ret;
+ break;
+ }
+ }
+
+ cur_offset = drop_end;
+
+ ret = btrfs_update_inode(trans, root, inode);
+ if (ret) {
+ err = ret;
+ break;
+ }
+
+ btrfs_end_transaction(trans);
+ btrfs_btree_balance_dirty(fs_info);
+
+ trans = btrfs_start_transaction(root, rsv_count);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ trans = NULL;
+ break;
+ }
+
+ ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
+ rsv, min_size, 0);
+ BUG_ON(ret); /* shouldn't happen */
+ trans->block_rsv = rsv;
+
+ ret = find_first_non_hole(inode, &cur_offset, &len);
+ if (unlikely(ret < 0))
+ break;
+ if (ret && !len) {
+ ret = 0;
+ break;
+ }
+ }
+
+ if (ret) {
+ err = ret;
+ goto out_trans;
+ }
+
+ trans->block_rsv = &fs_info->trans_block_rsv;
+ /*
+ * If we are using the NO_HOLES feature we might have had already an
+ * hole that overlaps a part of the region [lockstart, lockend] and
+ * ends at (or beyond) lockend. Since we have no file extent items to
+ * represent holes, drop_end can be less than lockend and so we must
+ * make sure we have an extent map representing the existing hole (the
+ * call to __btrfs_drop_extents() might have dropped the existing extent
+ * map representing the existing hole), otherwise the fast fsync path
+ * will not record the existence of the hole region
+ * [existing_hole_start, lockend].
+ */
+ if (drop_end <= lockend)
+ drop_end = lockend + 1;
+ /*
+ * Don't insert file hole extent item if it's for a range beyond eof
+ * (because it's useless) or if it represents a 0 bytes range (when
+ * cur_offset == drop_end).
+ */
+ if (cur_offset < ino_size && cur_offset < drop_end) {
+ ret = fill_holes(trans, BTRFS_I(inode), path,
+ cur_offset, drop_end);
+ if (ret) {
+ /* Same comment as above. */
+ btrfs_abort_transaction(trans, ret);
+ err = ret;
+ goto out_trans;
+ }
+ }
+
+out_trans:
+ if (!trans)
+ goto out_free;
+
+ inode_inc_iversion(inode);
+ inode->i_mtime = inode->i_ctime = current_time(inode);
+
+ trans->block_rsv = &fs_info->trans_block_rsv;
+ ret = btrfs_update_inode(trans, root, inode);
+ updated_inode = true;
+ btrfs_end_transaction(trans);
+ btrfs_btree_balance_dirty(fs_info);
+out_free:
+ btrfs_free_path(path);
+ btrfs_free_block_rsv(fs_info, rsv);
+out:
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ &cached_state);
+out_only_mutex:
+ if (!updated_inode && truncated_block && !ret && !err) {
+ /*
+ * If we only end up zeroing part of a page, we still need to
+ * update the inode item, so that all the time fields are
+ * updated as well as the necessary btrfs inode in memory fields
+ * for detecting, at fsync time, if the inode isn't yet in the
+ * log tree or it's there but not up to date.
+ */
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ } else {
+ err = btrfs_update_inode(trans, root, inode);
+ ret = btrfs_end_transaction(trans);
+ }
+ }
+ inode_unlock(inode);
+ if (ret && !err)
+ err = ret;
+ return err;
+}
+
+/* Helper structure to record which range is already reserved */
+struct falloc_range {
+ struct list_head list;
+ u64 start;
+ u64 len;
+};
+
+/*
+ * Helper function to add falloc range
+ *
+ * Caller should have locked the larger range of extent containing
+ * [start, len)
+ */
+static int add_falloc_range(struct list_head *head, u64 start, u64 len)
+{
+ struct falloc_range *prev = NULL;
+ struct falloc_range *range = NULL;
+
+ if (list_empty(head))
+ goto insert;
+
+ /*
+ * As fallocate iterate by bytenr order, we only need to check
+ * the last range.
+ */
+ prev = list_entry(head->prev, struct falloc_range, list);
+ if (prev->start + prev->len == start) {
+ prev->len += len;
+ return 0;
+ }
+insert:
+ range = kmalloc(sizeof(*range), GFP_KERNEL);
+ if (!range)
+ return -ENOMEM;
+ range->start = start;
+ range->len = len;
+ list_add_tail(&range->list, head);
+ return 0;
+}
+
+static int btrfs_fallocate_update_isize(struct inode *inode,
+ const u64 end,
+ const int mode)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret;
+ int ret2;
+
+ if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode))
+ return 0;
+
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ inode->i_ctime = current_time(inode);
+ i_size_write(inode, end);
+ btrfs_ordered_update_i_size(inode, end, NULL);
+ ret = btrfs_update_inode(trans, root, inode);
+ ret2 = btrfs_end_transaction(trans);
+
+ return ret ? ret : ret2;
+}
+
+enum {
+ RANGE_BOUNDARY_WRITTEN_EXTENT = 0,
+ RANGE_BOUNDARY_PREALLOC_EXTENT = 1,
+ RANGE_BOUNDARY_HOLE = 2,
+};
+
+static int btrfs_zero_range_check_range_boundary(struct inode *inode,
+ u64 offset)
+{
+ const u64 sectorsize = btrfs_inode_sectorsize(inode);
+ struct extent_map *em;
+ int ret;
+
+ offset = round_down(offset, sectorsize);
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, sectorsize, 0);
+ if (IS_ERR(em))
+ return PTR_ERR(em);
+
+ if (em->block_start == EXTENT_MAP_HOLE)
+ ret = RANGE_BOUNDARY_HOLE;
+ else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
+ ret = RANGE_BOUNDARY_PREALLOC_EXTENT;
+ else
+ ret = RANGE_BOUNDARY_WRITTEN_EXTENT;
+
+ free_extent_map(em);
+ return ret;
+}
+
+static int btrfs_zero_range(struct inode *inode,
+ loff_t offset,
+ loff_t len,
+ const int mode)
+{
+ struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
+ struct extent_map *em;
+ struct extent_changeset *data_reserved = NULL;
+ int ret;
+ u64 alloc_hint = 0;
+ const u64 sectorsize = btrfs_inode_sectorsize(inode);
+ u64 alloc_start = round_down(offset, sectorsize);
+ u64 alloc_end = round_up(offset + len, sectorsize);
+ u64 bytes_to_reserve = 0;
+ bool space_reserved = false;
+
+ inode_dio_wait(inode);
+
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
+ alloc_start, alloc_end - alloc_start, 0);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out;
+ }
+
+ /*
+ * Avoid hole punching and extent allocation for some cases. More cases
+ * could be considered, but these are unlikely common and we keep things
+ * as simple as possible for now. Also, intentionally, if the target
+ * range contains one or more prealloc extents together with regular
+ * extents and holes, we drop all the existing extents and allocate a
+ * new prealloc extent, so that we get a larger contiguous disk extent.
+ */
+ if (em->start <= alloc_start &&
+ test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
+ const u64 em_end = em->start + em->len;
+
+ if (em_end >= offset + len) {
+ /*
+ * The whole range is already a prealloc extent,
+ * do nothing except updating the inode's i_size if
+ * needed.
+ */
+ free_extent_map(em);
+ ret = btrfs_fallocate_update_isize(inode, offset + len,
+ mode);
+ goto out;
+ }
+ /*
+ * Part of the range is already a prealloc extent, so operate
+ * only on the remaining part of the range.
+ */
+ alloc_start = em_end;
+ ASSERT(IS_ALIGNED(alloc_start, sectorsize));
+ len = offset + len - alloc_start;
+ offset = alloc_start;
+ alloc_hint = em->block_start + em->len;
+ }
+ free_extent_map(em);
+
+ if (BTRFS_BYTES_TO_BLKS(fs_info, offset) ==
+ BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) {
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0,
+ alloc_start, sectorsize, 0);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out;
+ }
+
+ if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
+ free_extent_map(em);
+ ret = btrfs_fallocate_update_isize(inode, offset + len,
+ mode);
+ goto out;
+ }
+ if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) {
+ free_extent_map(em);
+ ret = btrfs_truncate_block(inode, offset, len, 0);
+ if (!ret)
+ ret = btrfs_fallocate_update_isize(inode,
+ offset + len,
+ mode);
+ return ret;
+ }
+ free_extent_map(em);
+ alloc_start = round_down(offset, sectorsize);
+ alloc_end = alloc_start + sectorsize;
+ goto reserve_space;
+ }
+
+ alloc_start = round_up(offset, sectorsize);
+ alloc_end = round_down(offset + len, sectorsize);
+
+ /*
+ * For unaligned ranges, check the pages at the boundaries, they might
+ * map to an extent, in which case we need to partially zero them, or
+ * they might map to a hole, in which case we need our allocation range
+ * to cover them.
+ */
+ if (!IS_ALIGNED(offset, sectorsize)) {
+ ret = btrfs_zero_range_check_range_boundary(inode, offset);
+ if (ret < 0)
+ goto out;
+ if (ret == RANGE_BOUNDARY_HOLE) {
+ alloc_start = round_down(offset, sectorsize);
+ ret = 0;
+ } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
+ ret = btrfs_truncate_block(inode, offset, 0, 0);
+ if (ret)
+ goto out;
+ } else {
+ ret = 0;
+ }
+ }
+
+ if (!IS_ALIGNED(offset + len, sectorsize)) {
+ ret = btrfs_zero_range_check_range_boundary(inode,
+ offset + len);
+ if (ret < 0)
+ goto out;
+ if (ret == RANGE_BOUNDARY_HOLE) {
+ alloc_end = round_up(offset + len, sectorsize);
+ ret = 0;
+ } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) {
+ ret = btrfs_truncate_block(inode, offset + len, 0, 1);
+ if (ret)
+ goto out;
+ } else {
+ ret = 0;
+ }
+ }
+
+reserve_space:
+ if (alloc_start < alloc_end) {
+ struct extent_state *cached_state = NULL;
+ const u64 lockstart = alloc_start;
+ const u64 lockend = alloc_end - 1;
+
+ bytes_to_reserve = alloc_end - alloc_start;
+ ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
+ bytes_to_reserve);
+ if (ret < 0)
+ goto out;
+ space_reserved = true;
+ ret = btrfs_qgroup_reserve_data(inode, &data_reserved,
+ alloc_start, bytes_to_reserve);
+ if (ret)
+ goto out;
+ ret = btrfs_punch_hole_lock_range(inode, lockstart, lockend,
+ &cached_state);
+ if (ret)
+ goto out;
+ ret = btrfs_prealloc_file_range(inode, mode, alloc_start,
+ alloc_end - alloc_start,
+ i_blocksize(inode),
+ offset + len, &alloc_hint);
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
+ lockend, &cached_state);
+ /* btrfs_prealloc_file_range releases reserved space on error */
+ if (ret) {
+ space_reserved = false;
+ goto out;
+ }
+ }
+ ret = btrfs_fallocate_update_isize(inode, offset + len, mode);
+ out:
+ if (ret && space_reserved)
+ btrfs_free_reserved_data_space(inode, data_reserved,
+ alloc_start, bytes_to_reserve);
+ extent_changeset_free(data_reserved);
+
+ return ret;
+}
+
+static long btrfs_fallocate(struct file *file, int mode,
+ loff_t offset, loff_t len)
+{
+ struct inode *inode = file_inode(file);
+ struct extent_state *cached_state = NULL;
+ struct extent_changeset *data_reserved = NULL;
+ struct falloc_range *range;
+ struct falloc_range *tmp;
+ struct list_head reserve_list;
+ u64 cur_offset;
+ u64 last_byte;
+ u64 alloc_start;
+ u64 alloc_end;
+ u64 alloc_hint = 0;
+ u64 locked_end;
+ u64 actual_end = 0;
+ struct extent_map *em;
+ int blocksize = btrfs_inode_sectorsize(inode);
+ int ret;
+
+ alloc_start = round_down(offset, blocksize);
+ alloc_end = round_up(offset + len, blocksize);
+ cur_offset = alloc_start;
+
+ /* Make sure we aren't being give some crap mode */
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+ FALLOC_FL_ZERO_RANGE))
+ return -EOPNOTSUPP;
+
+ if (mode & FALLOC_FL_PUNCH_HOLE)
+ return btrfs_punch_hole(inode, offset, len);
+
+ /*
+ * Only trigger disk allocation, don't trigger qgroup reserve
+ *
+ * For qgroup space, it will be checked later.
+ */
+ if (!(mode & FALLOC_FL_ZERO_RANGE)) {
+ ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode),
+ alloc_end - alloc_start);
+ if (ret < 0)
+ return ret;
+ }
+
+ inode_lock(inode);
+
+ if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) {
+ ret = inode_newsize_ok(inode, offset + len);
+ if (ret)
+ goto out;
+ }
+
+ /*
+ * TODO: Move these two operations after we have checked
+ * accurate reserved space, or fallocate can still fail but
+ * with page truncated or size expanded.
+ *
+ * But that's a minor problem and won't do much harm BTW.
+ */
+ if (alloc_start > inode->i_size) {
+ ret = btrfs_cont_expand(inode, i_size_read(inode),
+ alloc_start);
+ if (ret)
+ goto out;
+ } else if (offset + len > inode->i_size) {
+ /*
+ * If we are fallocating from the end of the file onward we
+ * need to zero out the end of the block if i_size lands in the
+ * middle of a block.
+ */
+ ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
+ if (ret)
+ goto out;
+ }
+
+ /*
+ * wait for ordered IO before we have any locks. We'll loop again
+ * below with the locks held.
+ */
+ ret = btrfs_wait_ordered_range(inode, alloc_start,
+ alloc_end - alloc_start);
+ if (ret)
+ goto out;
+
+ if (mode & FALLOC_FL_ZERO_RANGE) {
+ ret = btrfs_zero_range(inode, offset, len, mode);
+ inode_unlock(inode);
+ return ret;
+ }
+
+ locked_end = alloc_end - 1;
+ while (1) {
+ struct btrfs_ordered_extent *ordered;
+
+ /* the extent lock is ordered inside the running
+ * transaction
+ */
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
+ locked_end, &cached_state);
+ ordered = btrfs_lookup_first_ordered_extent(inode, locked_end);
+
+ if (ordered &&
+ ordered->file_offset + ordered->len > alloc_start &&
+ ordered->file_offset < alloc_end) {
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+ alloc_start, locked_end,
+ &cached_state);
+ /*
+ * we can't wait on the range with the transaction
+ * running or with the extent lock held
+ */
+ ret = btrfs_wait_ordered_range(inode, alloc_start,
+ alloc_end - alloc_start);
+ if (ret)
+ goto out;
+ } else {
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ break;
+ }
+ }
+
+ /* First, check if we exceed the qgroup limit */
+ INIT_LIST_HEAD(&reserve_list);
+ while (cur_offset < alloc_end) {
+ em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
+ alloc_end - cur_offset, 0);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ break;
+ }
+ last_byte = min(extent_map_end(em), alloc_end);
+ actual_end = min_t(u64, extent_map_end(em), offset + len);
+ last_byte = ALIGN(last_byte, blocksize);
+ if (em->block_start == EXTENT_MAP_HOLE ||
+ (cur_offset >= inode->i_size &&
+ !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
+ ret = add_falloc_range(&reserve_list, cur_offset,
+ last_byte - cur_offset);
+ if (ret < 0) {
+ free_extent_map(em);
+ break;
+ }
+ ret = btrfs_qgroup_reserve_data(inode, &data_reserved,
+ cur_offset, last_byte - cur_offset);
+ if (ret < 0) {
+ free_extent_map(em);
+ break;
+ }
+ } else {
+ /*
+ * Do not need to reserve unwritten extent for this
+ * range, free reserved data space first, otherwise
+ * it'll result in false ENOSPC error.
+ */
+ btrfs_free_reserved_data_space(inode, data_reserved,
+ cur_offset, last_byte - cur_offset);
+ }
+ free_extent_map(em);
+ cur_offset = last_byte;
+ }
+
+ /*
+ * If ret is still 0, means we're OK to fallocate.
+ * Or just cleanup the list and exit.
+ */
+ list_for_each_entry_safe(range, tmp, &reserve_list, list) {
+ if (!ret)
+ ret = btrfs_prealloc_file_range(inode, mode,
+ range->start,
+ range->len, i_blocksize(inode),
+ offset + len, &alloc_hint);
+ else
+ btrfs_free_reserved_data_space(inode,
+ data_reserved, range->start,
+ range->len);
+ list_del(&range->list);
+ kfree(range);
+ }
+ if (ret < 0)
+ goto out_unlock;
+
+ /*
+ * We didn't need to allocate any more space, but we still extended the
+ * size of the file so we need to update i_size and the inode item.
+ */
+ ret = btrfs_fallocate_update_isize(inode, actual_end, mode);
+out_unlock:
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
+ &cached_state);
+out:
+ inode_unlock(inode);
+ /* Let go of our reservation. */
+ if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE))
+ btrfs_free_reserved_data_space(inode, data_reserved,
+ alloc_start, alloc_end - cur_offset);
+ extent_changeset_free(data_reserved);
+ return ret;
+}
+
+static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct extent_map *em = NULL;
+ struct extent_state *cached_state = NULL;
+ u64 lockstart;
+ u64 lockend;
+ u64 start;
+ u64 len;
+ int ret = 0;
+
+ if (inode->i_size == 0)
+ return -ENXIO;
+
+ /*
+ * *offset can be negative, in this case we start finding DATA/HOLE from
+ * the very start of the file.
+ */
+ start = max_t(loff_t, 0, *offset);
+
+ lockstart = round_down(start, fs_info->sectorsize);
+ lockend = round_up(i_size_read(inode),
+ fs_info->sectorsize);
+ if (lockend <= lockstart)
+ lockend = lockstart + fs_info->sectorsize;
+ lockend--;
+ len = lockend - lockstart + 1;
+
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ &cached_state);
+
+ while (start < inode->i_size) {
+ em = btrfs_get_extent_fiemap(BTRFS_I(inode), NULL, 0,
+ start, len, 0);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ em = NULL;
+ break;
+ }
+
+ if (whence == SEEK_HOLE &&
+ (em->block_start == EXTENT_MAP_HOLE ||
+ test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
+ break;
+ else if (whence == SEEK_DATA &&
+ (em->block_start != EXTENT_MAP_HOLE &&
+ !test_bit(EXTENT_FLAG_PREALLOC, &em->flags)))
+ break;
+
+ start = em->start + em->len;
+ free_extent_map(em);
+ em = NULL;
+ cond_resched();
+ }
+ free_extent_map(em);
+ if (!ret) {
+ if (whence == SEEK_DATA && start >= inode->i_size)
+ ret = -ENXIO;
+ else
+ *offset = min_t(loff_t, start, inode->i_size);
+ }
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ &cached_state);
+ return ret;
+}
+
+static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_mapping->host;
+ int ret;
+
+ inode_lock(inode);
+ switch (whence) {
+ case SEEK_END:
+ case SEEK_CUR:
+ offset = generic_file_llseek(file, offset, whence);
+ goto out;
+ case SEEK_DATA:
+ case SEEK_HOLE:
+ if (offset >= i_size_read(inode)) {
+ inode_unlock(inode);
+ return -ENXIO;
+ }
+
+ ret = find_desired_extent(inode, &offset, whence);
+ if (ret) {
+ inode_unlock(inode);
+ return ret;
+ }
+ }
+
+ offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
+out:
+ inode_unlock(inode);
+ return offset;
+}
+
+static int btrfs_file_open(struct inode *inode, struct file *filp)
+{
+ filp->f_mode |= FMODE_NOWAIT;
+ return generic_file_open(inode, filp);
+}
+
+const struct file_operations btrfs_file_operations = {
+ .llseek = btrfs_file_llseek,
+ .read_iter = generic_file_read_iter,
+ .splice_read = generic_file_splice_read,
+ .write_iter = btrfs_file_write_iter,
+ .mmap = btrfs_file_mmap,
+ .open = btrfs_file_open,
+ .release = btrfs_release_file,
+ .fsync = btrfs_sync_file,
+ .fallocate = btrfs_fallocate,
+ .unlocked_ioctl = btrfs_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = btrfs_compat_ioctl,
+#endif
+ .clone_file_range = btrfs_clone_file_range,
+ .dedupe_file_range = btrfs_dedupe_file_range,
+};
+
+void __cold btrfs_auto_defrag_exit(void)
+{
+ kmem_cache_destroy(btrfs_inode_defrag_cachep);
+}
+
+int __init btrfs_auto_defrag_init(void)
+{
+ btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
+ sizeof(struct inode_defrag), 0,
+ SLAB_MEM_SPREAD,
+ NULL);
+ if (!btrfs_inode_defrag_cachep)
+ return -ENOMEM;
+
+ return 0;
+}
+
+int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end)
+{
+ int ret;
+
+ /*
+ * So with compression we will find and lock a dirty page and clear the
+ * first one as dirty, setup an async extent, and immediately return
+ * with the entire range locked but with nobody actually marked with
+ * writeback. So we can't just filemap_write_and_wait_range() and
+ * expect it to work since it will just kick off a thread to do the
+ * actual work. So we need to call filemap_fdatawrite_range _again_
+ * since it will wait on the page lock, which won't be unlocked until
+ * after the pages have been marked as writeback and so we're good to go
+ * from there. We have to do this otherwise we'll miss the ordered
+ * extents and that results in badness. Please Josef, do not think you
+ * know better and pull this out at some point in the future, it is
+ * right and you are wrong.
+ */
+ ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
+ if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
+ &BTRFS_I(inode)->runtime_flags))
+ ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
+
+ return ret;
+}