Re: [PATCH 2/2] btrfs: reada: Fix returned errno code

[David Sterba <dsterba@suse.cz>]

On Tue, Sep 22, 2015 at 05:29:39PM +0100, Luis de Bethencourt wrote:
> reada is using -1 instead of the -ENOMEM defined macro to specify that
> a buffer allocation failed. Since the error number is propagated, the
> caller will get a -EPERM which is the wrong error condition.
> 
> Smatch tool warning:
> reada_add_block() warn: returning -1 instead of -ENOMEM is sloppy
> 
> Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
> ---
>  fs/btrfs/reada.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
> index 4645cd1..5bfd3cd 100644
> --- a/fs/btrfs/reada.c
> +++ b/fs/btrfs/reada.c
> @@ -569,7 +569,7 @@ static int reada_add_block(struct reada_control *rc, u64 logical,
>  	rec = kzalloc(sizeof(*rec), GFP_NOFS);
>  	if (!rec) {
>  		reada_extent_put(root->fs_info, re);
> -		return -1;
> +		return -ENOMEM;

When called from btrfs_reada_add, the return value is ignored and
overriden as ENOMEM. Please also update the caller to return the exact
value from reada_add_block.