Gui Hecheng
2014-Jan-23 05:41 UTC
[PATCH] btrfs: fix warning while merging two adjacent extents
When we have two adjacent extents in relink_extent_backref, we try to merge them. When we use btrfs_search_slot to locate the slot for the current extent, we shouldn't set "ins_len = 1", because we will merge it into the previous extent rather than insert a new item. Otherwise, we may happen to create a new leaf in btrfs_search_slot and path->slot[0] will be 0. Then we try to fetch the previous item using "path->slots[0]--", and it will cause a warning as follows: [ 145.713385] WARNING: CPU: 3 PID: 1796 at fs/btrfs/extent_io.c:5043 map_private_extent_buffer+0xd4/0xe0 [ 145.713387] btrfs bad mapping eb start 5337088 len 4096, wanted 167772306 8 ... [ 145.713462] [<ffffffffa034b1f4>] map_private_extent_buffer+0xd4/0xe0 [ 145.713476] [<ffffffffa030097a>] ? btrfs_free_path+0x2a/0x40 [ 145.713485] [<ffffffffa0340864>] btrfs_get_token_64+0x64/0xf0 [ 145.713498] [<ffffffffa033472c>] relink_extent_backref+0x41c/0x820 [ 145.713508] [<ffffffffa0334d69>] btrfs_finish_ordered_io+0x239/0xa80 I encounter this warning when running defrag having mkfs.btrfs with option -M. At the same time there are read/writes & snapshots running at background. Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com> --- fs/btrfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 1ea19ce..7f955d6 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -2314,7 +2314,7 @@ again: u64 extent_len; struct btrfs_key found_key; - ret = btrfs_search_slot(trans, root, &key, path, 1, 1); + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); if (ret < 0) goto out_free_path; -- 1.8.0.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html