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Commit 1ba98d08 authored by Liu Bo's avatar Liu Bo Committed by Chris Mason
Browse files

Btrfs: detect corruption when non-root leaf has zero item 



Right now we treat leaf which has zero item as a valid one
because we could have an empty tree, that is, a root that is
also a leaf without any item, however, in the same case but
when the leaf is not a root, we can end up with hitting the
BUG_ON(1) in btrfs_extend_item() called by
setup_inline_extent_backref().

This makes us check the situation as a corruption if leaf is
not its own root.

Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 053ab70f

fs/btrfs/disk-io.c

+22 −1
Original line number Diff line number Diff line
@@ -560,8 +560,29 @@ static noinline int check_leaf(struct btrfs_root *root, 
	u32 nritems = btrfs_header_nritems(leaf);

	int slot;



	if (nritems == 0)

	if (nritems == 0) {

		struct btrfs_root *check_root;



		key.objectid = btrfs_header_owner(leaf);

		key.type = BTRFS_ROOT_ITEM_KEY;

		key.offset = (u64)-1;



		check_root = btrfs_get_fs_root(root->fs_info, &key, false);

		/*

		 * The only reason we also check NULL here is that during

		 * open_ctree() some roots has not yet been set up.

		 */

		if (!IS_ERR_OR_NULL(check_root)) {

			/* if leaf is the root, then it's fine */

			if (leaf->start !=

			    btrfs_root_bytenr(&check_root->root_item)) {

				CORRUPT("non-root leaf's nritems is 0",

					leaf, root, 0);

				return -EIO;

			}

		}

		return 0;

	}



	/* Check the 0 item */

	if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=