| From | Jiri Slaby <> | Subject | [PATCH 3.12 011/142] Btrfs: read lock extent buffer while walking backrefs | Date | Fri, 26 Sep 2014 11:43:42 +0200 |
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From: Filipe Manana <fdmanana@suse.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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commit 6f7ff6d7832c6be13e8c95598884dbc40ad69fb7 upstream.
Before processing the extent buffer, acquire a read lock on it, so that we're safe against concurrent updates on the extent buffer.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- fs/btrfs/backref.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 715cfa42e182..53039de1495d 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -954,8 +954,11 @@ again: ret = -EIO; goto out; } + btrfs_tree_read_lock(eb); + btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); ret = find_extent_in_eb(eb, bytenr, *extent_item_pos, &eie); + btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); if (ret < 0) goto out; -- 2.1.0
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