Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 835d974f authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: handle a bogus chunk tree nicely 



If you restore a btrfs-image file system and try to mount that file system we'll
panic.  That's because btrfs-image restores and just makes one big chunk to
envelope the whole disk, since they are really only meant to be messed with by
our btrfs-progs.  So fix up btrfs_rmap_block and the callers of it for mount so
that we no longer panic but instead just return an error and fail to mount.
Thanks,

Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent d7634482

fs/btrfs/extent-tree.c

+30 −5
Original line number Diff line number Diff line
@@ -257,7 +257,8 @@ static int exclude_super_stripes(struct btrfs_root *root, 
		cache->bytes_super += stripe_len;

		ret = add_excluded_extent(root, cache->key.objectid,

					  stripe_len);

		BUG_ON(ret); /* -ENOMEM */

		if (ret)

			return ret;

	}



	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
@@ -265,13 +266,17 @@ static int exclude_super_stripes(struct btrfs_root *root, 
		ret = btrfs_rmap_block(&root->fs_info->mapping_tree,

				       cache->key.objectid, bytenr,

				       0, &logical, &nr, &stripe_len);

		BUG_ON(ret); /* -ENOMEM */

		if (ret)

			return ret;



		while (nr--) {

			cache->bytes_super += stripe_len;

			ret = add_excluded_extent(root, logical[nr],

						  stripe_len);

			BUG_ON(ret); /* -ENOMEM */

			if (ret) {

				kfree(logical);

				return ret;

			}

		}



		kfree(logical);
@@ -7964,7 +7969,17 @@ int btrfs_read_block_groups(struct btrfs_root *root) 
		 * info has super bytes accounted for, otherwise we'll think

		 * we have more space than we actually do.

		 */

		exclude_super_stripes(root, cache);

		ret = exclude_super_stripes(root, cache);

		if (ret) {

			/*

			 * We may have excluded something, so call this just in

			 * case.

			 */

			free_excluded_extents(root, cache);

			kfree(cache->free_space_ctl);

			kfree(cache);

			goto error;

		}



		/*

		 * check for two cases, either we are full, and therefore
@@ -8106,7 +8121,17 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, 


	cache->last_byte_to_unpin = (u64)-1;

	cache->cached = BTRFS_CACHE_FINISHED;

	exclude_super_stripes(root, cache);

	ret = exclude_super_stripes(root, cache);

	if (ret) {

		/*

		 * We may have excluded something, so call this just in

		 * case.

		 */

		free_excluded_extents(root, cache);

		kfree(cache->free_space_ctl);

		kfree(cache);

		return ret;

	}



	add_new_free_space(cache, root->fs_info, chunk_offset,

			   chunk_offset + size);

fs/btrfs/volumes.c

+12 −1
Original line number Diff line number Diff line
@@ -4935,7 +4935,18 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree, 
	em = lookup_extent_mapping(em_tree, chunk_start, 1);

	read_unlock(&em_tree->lock);



	BUG_ON(!em || em->start != chunk_start);

	if (!em) {

		printk(KERN_ERR "btrfs: couldn't find em for chunk %Lu\n",

		       chunk_start);

		return -EIO;

	}



	if (em->start != chunk_start) {

		printk(KERN_ERR "btrfs: bad chunk start, em=%Lu, wanted=%Lu\n",

		       em->start, chunk_start);

		free_extent_map(em);

		return -EIO;

	}

	map = (struct map_lookup *)em->bdev;



	length = em->len;