Commit 1b1d1f66 authored by Josef Bacik's avatar Josef Bacik Committed by Chris Mason
Browse files

Btrfs: fail to mount if we have problems reading the block groups 



We don't actually check the return value of btrfs_read_block_groups, so we can
possibly succeed to mount, but then fail to say read the superblock xattr for
selinux which will cause the vfs code to deactivate the super.

This is a problem because in find_free_extent we just assume that we
will find the right space_info for the allocation we want.  But if we
failed to read the block groups, we won't have setup any space_info's,
and we'll hit a NULL pointer deref in find_free_extent.

This patch fixes that problem by checking the return value of
btrfs_read_block_groups, and failing out properly.  I've also added a
check in find_free_extent so if for some reason we don't find an
appropriate space_info, we just return -ENOSPC.

Signed-off-by: default avatarJosef Bacik <josef@redhat.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 6cf8bfbf

fs/btrfs/disk-io.c

+8 −3
Original line number Diff line number Diff line
@@ -1922,7 +1922,11 @@ struct btrfs_root *open_ctree(struct super_block *sb, 


	csum_root->track_dirty = 1;



	btrfs_read_block_groups(extent_root);

	ret = btrfs_read_block_groups(extent_root);

	if (ret) {

		printk(KERN_ERR "Failed to read block groups: %d\n", ret);

		goto fail_block_groups;

	}



	fs_info->generation = generation;

	fs_info->last_trans_committed = generation;
@@ -1932,7 +1936,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,

					       "btrfs-cleaner");

	if (IS_ERR(fs_info->cleaner_kthread))

		goto fail_csum_root;

		goto fail_block_groups;



	fs_info->transaction_kthread = kthread_run(transaction_kthread,

						   tree_root,
@@ -2020,7 +2024,8 @@ fail_cleaner: 
	filemap_write_and_wait(fs_info->btree_inode->i_mapping);

	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);



fail_csum_root:

fail_block_groups:

	btrfs_free_block_groups(fs_info);

	free_extent_buffer(csum_root->node);

	free_extent_buffer(csum_root->commit_root);

fail_dev_root:

fs/btrfs/extent-tree.c

+4 −1
Original line number Diff line number Diff line
@@ -4170,6 +4170,10 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans, 
	ins->offset = 0;



	space_info = __find_space_info(root->fs_info, data);

	if (!space_info) {

		printk(KERN_ERR "No space info for %d\n", data);

		return -ENOSPC;

	}



	if (orig_root->ref_cows || empty_size)

		allowed_chunk_alloc = 1;
@@ -7372,7 +7376,6 @@ static int find_first_block_group(struct btrfs_root *root, 
		}

		path->slots[0]++;

	}

	ret = -ENOENT;

out:

	return ret;

}

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