Commit b753612b authored by Mark Harmstone's avatar Mark Harmstone Committed by David Sterba
Browse files

btrfs: tree-checker: add remap-tree checks to check_block_group_item() 



Add some write-time checks for block group items relating to the remap
tree.

Here we're checking:

* That the REMAPPED or METADATA_REMAP flags aren't set unless the
  REMAP_TREE incompat flag is also set
* That `remap_bytes` isn't more than the size of the block group
* That `identity_remap_count` isn't more than the number of sectors in
  the block group

Signed-off-by: default avatarMark Harmstone <mark@harmstone.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e3799e65

fs/btrfs/tree-checker.c

+41 −0
Original line number Diff line number Diff line
@@ -777,6 +777,47 @@ static int check_block_group_item(struct extent_buffer *leaf, 
			BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA);

		return -EUCLEAN;

	}



	if (unlikely(!btrfs_fs_incompat(fs_info, REMAP_TREE) &&

		     type == BTRFS_BLOCK_GROUP_METADATA_REMAP)) {

		block_group_err(leaf, slot,

		"invalid type, METADATA_REMAP set but REMAP_TREE incompat flag not set");

		return -EUCLEAN;

	}



	if (unlikely(!btrfs_fs_incompat(fs_info, REMAP_TREE) &&

		     flags & BTRFS_BLOCK_GROUP_REMAPPED)) {

		block_group_err(leaf, slot,

		"invalid flags, REMAPPED set but REMAP_TREE incompat flag not set");

		return -EUCLEAN;

	}



	if (item_size == sizeof(struct btrfs_block_group_item_v2)) {

		struct btrfs_block_group_item_v2 *bgi2;

		u64 remap_bytes;

		u32 identity_remap_count;



		bgi2 = btrfs_item_ptr(leaf, slot, struct btrfs_block_group_item_v2);

		remap_bytes = btrfs_block_group_v2_remap_bytes(leaf, bgi2);



		if (unlikely(remap_bytes > key->offset)) {

			block_group_err(leaf, slot,

				"invalid remap_bytes, have %llu expect [0, %llu]",

					remap_bytes, key->offset);

			return -EUCLEAN;

		}



		identity_remap_count = btrfs_block_group_v2_identity_remap_count(leaf, bgi2);

		if (unlikely((u64)identity_remap_count >

			     key->offset >> fs_info->sectorsize_bits)) {

			block_group_err(leaf, slot,

				"invalid identity_remap_count, have %u expect [0, %llu]",

					identity_remap_count,

					key->offset >> fs_info->sectorsize_bits);

			return -EUCLEAN;

		}

	}



	return 0;

}