Btrfs: detect corruption when non-root leaf has zero item (1ba98d08) · Commits · 戴 / test

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:

Liu Bo <bo.li.liu@oracle.com> Reviewed-by:

David Sterba <dsterba@suse.com> Signed-off-by:

Chris Mason <clm@fb.com>

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) !=

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