Re: [PATCH 1/5] Btrfs: fix btrfs_read_block_groups return value

[Jeff Mahoney <jeffm@suse.com>]

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BTW Chris, these 5 patches are currently queued up on my git tree:

git://jeffreymahoney.com/linux/btrfs-unstable for-mason

- -Jeff

Jeff Mahoney wrote:
>  btrfs_read_block_groups returns an ambiguous value. Whether it finds
>  a block group or not, it will return -ENOENT. find_first_block_group
>  will eventually return -ENOENT when it reaches past the last block
>  group, and that is what is returned to the caller.
> 
>  Also, if the kzalloc fails, it will return 0.
> 
>  None of this matters right now because open_ctree() isn't checking
>  the return value, but I have a patch to handle that as well.
> 
>  This patch returns 0 if find_first_block_group after it has already
>  found at least one block group, and -ENOENT if it has found none. Other
>  errors are reported as expected.
> 
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> ---
>  fs/btrfs/extent-tree.c |   12 ++++++------
>  1 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 0a5d796..777af73 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -6125,7 +6125,7 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
>  int btrfs_read_block_groups(struct btrfs_root *root)
>  {
>  	struct btrfs_path *path;
> -	int ret;
> +	int ret, found = 0;
>  	struct btrfs_block_group_cache *cache;
>  	struct btrfs_fs_info *info = root->fs_info;
>  	struct btrfs_space_info *space_info;
> @@ -6143,12 +6143,13 @@ int btrfs_read_block_groups(struct btrfs_root *root)
>  
>  	while (1) {
>  		ret = find_first_block_group(root, path, &key);
> -		if (ret > 0) {
> +		if (ret > 0 || (found && ret == -ENOENT)) {
>  			ret = 0;
> -			goto error;
> +			break;
>  		}
> +
>  		if (ret != 0)
> -			goto error;
> +			break;
>  
>  		leaf = path->nodes[0];
>  		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
> @@ -6187,9 +6188,8 @@ int btrfs_read_block_groups(struct btrfs_root *root)
>  		set_avail_alloc_bits(root->fs_info, cache->flags);
>  		if (btrfs_chunk_readonly(root, cache->key.objectid))
>  			set_block_group_readonly(cache);
> +		found = 1;
>  	}
> -	ret = 0;
> -error:
>  	btrfs_free_path(path);
>  	return ret;
>  }


- --
Jeff Mahoney
SUSE Labs
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