Re: [PATCH v3 6/6] btrfs: rename and optimize return variable in btrfs_find_orphan_roots

[David Sterba <dsterba@suse.cz>]

On Wed, May 22, 2024 at 01:10:08AM +0800, Anand Jain wrote:
> 
> 
> On 5/21/24 23:18, David Sterba wrote:
> > On Thu, May 16, 2024 at 07:12:15PM +0800, Anand Jain wrote:
> >> The variable err is the actual return value of this function, and the
> >> variable ret is a helper variable for err, which actually is not
> >> needed and can be handled just by err, which is renamed to ret.
> >>
> >> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> >> ---
> >> v3: drop ret2 as there is no need for it.
> >> v2: n/a
> >>   fs/btrfs/root-tree.c | 32 ++++++++++++++++----------------
> >>   1 file changed, 16 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
> >> index 33962671a96c..c11b0bccf513 100644
> >> --- a/fs/btrfs/root-tree.c
> >> +++ b/fs/btrfs/root-tree.c
> >> @@ -220,8 +220,7 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
> >>   	struct btrfs_path *path;
> >>   	struct btrfs_key key;
> >>   	struct btrfs_root *root;
> >> -	int err = 0;
> >> -	int ret;
> >> +	int ret = 0;
> >>   
> >>   	path = btrfs_alloc_path();
> >>   	if (!path)
> >> @@ -235,18 +234,19 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
> >>   		u64 root_objectid;
> >>   
> >>   		ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
> >> -		if (ret < 0) {
> >> -			err = ret;
> >> +		if (ret < 0)
> >>   			break;
> >> -		}
> >> +		ret = 0;
> > 
> > Should this be handled when ret > 0? This would be unexpected and
> > probably means a corruption but simply overwriting the value does not
> > seem right.
> > 
> 
> Agreed.
> 
> +               if (ret > 0)
> +                       ret = 0;
> 
> is much neater.

That's not what I meant. When btrfs_search_slot() returns 1 then the key
was not found and could be inserted, path points to the slot. This is
done in many other places, so in the orphan root lookup it should be
also handled.