| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.16 086/125] Btrfs: read lock extent buffer while walking backrefs | Date | Wed, 3 Sep 2014 15:07:23 -0700 |
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3.16-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana <fdmanana@suse.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/btrfs/backref.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1000,8 +1000,11 @@ 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;
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