linux-kernel - Re: [PATCH 1/1] cifs: potential missing check for posix_lock_file

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Date:	Fri, 3 Apr 2015 08:11:25 -0400
From:	Jeff Layton <jeff.layton@...marydata.com>
To:	Chengyu Song <csong84@...ech.edu>
Cc:	sfrench@...ba.org, linux-cifs@...r.kernel.org,
	samba-technical@...ts.samba.org, linux-kernel@...r.kernel.org,
	taesoo@...ech.edu, changwoo@...ech.edu, sanidhya@...ech.edu,
	blee@...ech.edu, Pavel Shilovsky <piastryyy@...il.com>
Subject: Re: [PATCH 1/1] cifs: potential missing check for
 posix_lock_file_wait

On Tue, 24 Mar 2015 20:18:49 -0400
Chengyu Song <csong84@...ech.edu> wrote:

> posix_lock_file_wait may fail under certain circumstances, and its result is
> usually checked/returned. But given the complexity of cifs, I'm not sure if
> the result is intentially left unchecked and always expected to succeed.
> 
> Signed-off-by: Chengyu Song <csong84@...ech.edu>
> ---
>  fs/cifs/file.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index a94b3e6..beef67b 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -1553,8 +1553,8 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u32 type,
>  		rc = server->ops->mand_unlock_range(cfile, flock, xid);
>  
>  out:
> -	if (flock->fl_flags & FL_POSIX)
> -		posix_lock_file_wait(file, flock);
> +	if (flock->fl_flags & FL_POSIX && !rc)
> +		rc = posix_lock_file_wait(file, flock);
>  	return rc;
>  }
>  

(cc'ing Pavel since he wrote a lot of this code)

I think your patch looks correct -- if we (for instance) get a memory
allocation failure while trying to set the local lock then I think we
probably don't want to return success. So...

    Acked-by: Jeff Layton <jeff.layton@...marydata.com>
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