From: Filipe Manana <fdmanana@xxxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== 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@xxxxxxxx> Signed-off-by: Chris Mason <clm@xxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html