Commit 7afbfde4 authored Aug 01, 2023 by Qu Wenruo Committed by Greg Kroah-Hartman Sep 23, 2023

btrfs: output extra debug info if we failed to find an inline backref

[ Upstream commit 7f72f50547b7af4ddf985b07fc56600a4deba281 ]

[BUG]
Syzbot reported several warning triggered inside
lookup_inline_extent_backref().

[CAUSE]
As usual, the reproducer doesn't reliably trigger locally here, but at
least we know the WARN_ON() is triggered when an inline backref can not
be found, and it can only be triggered when @insert is true. (I.e.
inserting a new inline backref, which means the backref should already
exist)

[ENHANCEMENT]
After the WARN_ON(), dump all the parameters and the extent tree
leaf to help debug.

Link: https://syzkaller.appspot.com/bug?extid=d6f9ff86c1d804ba2bc6


Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 6079dc77

fs/btrfs/extent-tree.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -895,6 +895,11 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
		err = -ENOENT;
		goto out;
		} else if (WARN_ON(ret)) {
		btrfs_print_leaf(path->nodes[0]);
		btrfs_err(fs_info,
		"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
		bytenr, num_bytes, parent, root_objectid, owner,
		offset);
		err = -EIO;
		goto out;
		}