Commit 57a0e674 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: tree-checker: Refactor root key check into separate function 



ROOT_ITEM key check itself is not as simple as single line check, and
will be reused for both ROOT_ITEM and DIR_ITEM/DIR_INDEX location key
check, so refactor such check into check_root_key().

Also since we are here, fix a comment error about ROOT_ITEM offset,
which is transid of snapshot creation, not some "older kernel behavior".

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent c23c77b0

fs/btrfs/tree-checker.c

+47 −15
Original line number Diff line number Diff line
@@ -428,6 +428,49 @@ static int check_inode_key(struct extent_buffer *leaf, struct btrfs_key *key, 
	return 0;

}



static int check_root_key(struct extent_buffer *leaf, struct btrfs_key *key,

			  int slot)

{

	struct btrfs_key item_key;

	bool is_root_item;



	btrfs_item_key_to_cpu(leaf, &item_key, slot);

	is_root_item = (item_key.type == BTRFS_ROOT_ITEM_KEY);



	/* No such tree id */

	if (key->objectid == 0) {

		if (is_root_item)

			generic_err(leaf, slot, "invalid root id 0");

		else

			dir_item_err(leaf, slot,

				     "invalid location key root id 0");

		return -EUCLEAN;

	}



	/* DIR_ITEM/INDEX/INODE_REF is not allowed to point to non-fs trees */

	if (!is_fstree(key->objectid) && !is_root_item) {

		dir_item_err(leaf, slot,

		"invalid location key objectid, have %llu expect [%llu, %llu]",

				key->objectid, BTRFS_FIRST_FREE_OBJECTID,

				BTRFS_LAST_FREE_OBJECTID);

		return -EUCLEAN;

	}



	/*

	 * ROOT_ITEM with non-zero offset means this is a snapshot, created at

	 * @offset transid.

	 * Furthermore, for location key in DIR_ITEM, its offset is always -1.

	 *

	 * So here we only check offset for reloc tree whose key->offset must

	 * be a valid tree.

	 */

	if (key->objectid == BTRFS_TREE_RELOC_OBJECTID && key->offset == 0) {

		generic_err(leaf, slot, "invalid root id 0 for reloc tree");

		return -EUCLEAN;

	}

	return 0;

}



static int check_dir_item(struct extent_buffer *leaf,

			  struct btrfs_key *key, struct btrfs_key *prev_key,

			  int slot)
@@ -978,22 +1021,11 @@ static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key, 
	struct btrfs_root_item ri;

	const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |

				     BTRFS_ROOT_SUBVOL_DEAD;

	int ret;



	/* No such tree id */

	if (key->objectid == 0) {

		generic_err(leaf, slot, "invalid root id 0");

		return -EUCLEAN;

	}



	/*

	 * Some older kernel may create ROOT_ITEM with non-zero offset, so here

	 * we only check offset for reloc tree whose key->offset must be a

	 * valid tree.

	 */

	if (key->objectid == BTRFS_TREE_RELOC_OBJECTID && key->offset == 0) {

		generic_err(leaf, slot, "invalid root id 0 for reloc tree");

		return -EUCLEAN;

	}

	ret = check_root_key(leaf, key, slot);

	if (ret < 0)

		return ret;



	if (btrfs_item_size_nr(leaf, slot) != sizeof(ri)) {

		generic_err(leaf, slot,

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