Re: [PATCH] xfs: perag may be null in xfs_imap()

["Darrick J. Wong" <djwong@kernel.org>]

On Fri, Jun 11, 2021 at 08:37:47AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Dan Carpenter's static checker reported:
> 
> The patch 7b13c5155182: "xfs: use perag for ialloc btree cursors"
> from Jun 2, 2021, leads to the following Smatch complaint:
> 
>     fs/xfs/libxfs/xfs_ialloc.c:2403 xfs_imap()
>     error: we previously assumed 'pag' could be null (see line 2294)
> 
> And it's right. Fix it.
> 
> Fixes: 7b13c5155182 ("xfs: use perag for ialloc btree cursors")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks correct to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/libxfs/xfs_ialloc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index 654a8d9681e1..57d9cb632983 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -2398,7 +2398,8 @@ xfs_imap(
>  	}
>  	error = 0;
>  out_drop:
> -	xfs_perag_put(pag);
> +	if (pag)
> +		xfs_perag_put(pag);
>  	return error;
>  }
>