Re: [PATCH v2] cifs: allow unlock flock and OFD lock across fork

[Pavel Shilovsky <piastryyy@gmail.com>]

It looks that I forgot to ack the patch:

Acked-by: Pavel Shilovsky <pshilov@microsoft.com>

--
Best regards,
Pavel Shilovsky

чт, 20 февр. 2020 г. в 18:30, Murphy Zhou <jencce.kernel@gmail.com>:
>
> Since commit d0677992d2af ("cifs: add support for flock") added
> support for flock, LTP/flock03[1] testcase started to fail.
>
> This testcase is testing flock lock and unlock across fork.
> The parent locks file and starts the child process, in which
> it unlock the same fd and lock the same file with another fd
> again. All the lock and unlock operation should succeed.
>
> Now the child process does not actually unlock the file, so
> the following lock fails. Fix this by allowing flock and OFD
> lock go through the unlock routine, not skipping if the unlock
> request comes from another process.
>
> Patch has been tested by LTP/xfstests on samba and Windows
> server, v3.11, with or without cache=none mount option.
>
> [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/flock/flock03.c
> Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
> ---
>  fs/cifs/smb2file.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
> index afe1f03aabe3..eebfbf3a8c80 100644
> --- a/fs/cifs/smb2file.c
> +++ b/fs/cifs/smb2file.c
> @@ -152,7 +152,12 @@ smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
>                     (li->offset + li->length))
>                         continue;
>                 if (current->tgid != li->pid)
> -                       continue;
> +                       /*
> +                        * flock and OFD lock are associated with an open
> +                        * file description, not the process.
> +                        */
> +                       if (!(flock->fl_flags & (FL_FLOCK | FL_OFDLCK)))
> +                               continue;
>                 if (cinode->can_cache_brlcks) {
>                         /*
>                          * We can cache brlock requests - simply remove a lock
> --
> 2.20.1
>
>