Re: [PATCH 1/1] cifs: potential missing check for posix_lock_file_wait

From: Jeff Layton
Date: Fri Apr 03 2015 - 08:11:35 EST


On Tue, 24 Mar 2015 20:18:49 -0400
Chengyu Song <csong84@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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@xxxxxxxxxxxxxxx>
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