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Add a per-inode lock around btrfs_drop_extents

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btrfs_drop_extents is always called with a range lock held on the inode.
But, it may operate on extents outside that range as it drops and splits
them.

This patch adds a per-inode mutex that is held while calling
btrfs_drop_extents and while inserting new extents into the tree.  It
prevents races from two procs working against adjacent ranges in the tree.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2008-07-17 12:54:40 -04:00
parent ba1da2f442
commit ee6e6504e1
4 changed files with 21 additions and 0 deletions
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8
fs/btrfs/file.c
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@@ -242,6 +242,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
u64 inline_size;
int did_inline = 0;
loff_t isize = i_size_read(inode);
start_pos = pos & ~((u64)root->sectorsize - 1);
@@ -275,6 +276,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
if (hole_size > 0) {
btrfs_wait_ordered_range(inode, last_pos_in_file,
last_pos_in_file + hole_size);
mutex_lock(&BTRFS_I(inode)->extent_mutex);
err = btrfs_drop_extents(trans, root, inode,
last_pos_in_file,
last_pos_in_file + hole_size,
@@ -289,6 +291,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
0, 0, hole_size, 0);
btrfs_drop_extent_cache(inode, last_pos_in_file,
last_pos_in_file + hole_size -1);
mutex_unlock(&BTRFS_I(inode)->extent_mutex);
btrfs_check_file(root, inode);
}
if (err)
@@ -321,6 +324,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
/* step one, delete the existing extents in this range */
aligned_end = (pos + write_bytes + root->sectorsize - 1) &
~((u64)root->sectorsize - 1);
mutex_lock(&BTRFS_I(inode)->extent_mutex);
err = btrfs_drop_extents(trans, root, inode, start_pos,
aligned_end, aligned_end, &hint_byte);
if (err)
@@ -332,9 +336,13 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
inline_size, pages, 0, num_pages);
btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
BUG_ON(err);
mutex_unlock(&BTRFS_I(inode)->extent_mutex);
did_inline = 1;
}
if (end_pos > isize) {
i_size_write(inode, end_pos);
if (did_inline)
BTRFS_I(inode)->disk_i_size = end_pos;
btrfs_update_inode(trans, root, inode);
}
failed: