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    DateMon, 27 Nov 2006 10:19:29 +0100
    From"Jesper Juhl" <>
    SubjectRe: [NFS] 2.6.17.8 - do_vfs_lock: VFS is out of sync with lock manager!
    Any chance we could get the patch below (or something similar) pushed
    into 2.6.19?
    
    
    On 21/11/06, Jesper Juhl <jesper.juhl@gmail.com> wrote:
    > On 21/08/06, Trond Myklebust <trond.myklebust@fys.uio.no> wrote:
    > > On Mon, 2006-08-21 at 13:34 +1000, Neil Brown wrote:
    > > > Looking in fs/nfs/file.c (at 2.6.18-rc4-mm1 if it matters, but 2.6.17
    > > > is much the same)
    > > >
    > > >  - do_vfs_lock is only called when the filesystem was mounted with
    > > >     -o nolock  EXCEPT
    > > >  - If a lock request to the server in interrupted (when mounted with
    > > >      -o intr) then do_vfs_lock is called to try to get the lock
    > > >     locally.  Normally equivalent code will be called inside
    > > >     fs/lockd/clntproc.c when the server replies that the lock has been
    > > >     gained.  In the case of an interrupt though this doesn't happen
    > > >     but the lock may still have happened on the server.  So we record
    > > >     locally that the lock was gained, to ensure that it gets unlocked
    > > >     when the process exits.
    > > >
    > > > As you don't have '-o nolocks' you must be hitting the second case.
    > > > The lock call to the server returns -EINTR or -ERESTARTSYS and
    > > > do_vfs_lock is called just-in-case.
    > > > As this is a just-in-case call, it is quite possible that the lock is
    > > > held by some other process, so getting an error is entirely possible.
    > > > So printing the message in this case seems wrong.
    > > >
    > > > On the other hand, printing the message in any other case seems wrong
    > > > too, as server locking is not being used, so there is nothing to get
    > > > out of sync with.
    > > >
    > > > As a further complication, I don't think that in the just-in-case
    > > > situation that it should risk waiting for the lock.
    > > > Now maybe we can be sure there is a pending signal which will break
    > > > out of any wait (though I'm worried about -ERESTARTSYS - that doesn't
    > > > imply a signal does it?), but I would feel more comfortable if
    > > > FL_SLEEP were turned off in that path.
    > > >
    > > > So: Trond:  Any obvious errors in the above?
    > > > Is the following patch ok?
    > >
    > > Could we instead replace it with a dprintk() that returns the value of
    > > "res"? That will keep it useful for debugging purposes.
    > >
    >
    > How about the below?
    > (compile tested only)
    >
    > Neil: I left your Signed-off-by line since I just modified your patch slightly.
    >
    > Since Gmail will probably mangle the inline patch, it is attached as well.
    >
    >
    > Signed-off-by: Neil Brown <neilb@suse.de>
    > Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
    > --
    >
    >  fs/nfs/file.c |   11 +++++++----
    >  1 files changed, 7 insertions(+), 4 deletions(-)
    >
    > diff --git a/fs/nfs/file.c b/fs/nfs/file.c
    > index cc93865..22572af 100644
    > --- a/fs/nfs/file.c
    > +++ b/fs/nfs/file.c
    > @@ -428,8 +428,8 @@ static int do_vfs_lock(struct file *file
    >                         BUG();
    >         }
    >         if (res < 0)
    > -               printk(KERN_WARNING "%s: VFS is out of sync with lock
    > manager!\n",
    > -                               __FUNCTION__);
    > +               dprintk("%s: VFS is out of sync with lock manager (res
    > = %d)!\n",
    > +                               __FUNCTION__, res);
    >         return res;
    >  }
    >
    > @@ -479,10 +479,13 @@ static int do_setlk(struct file *filp, i
    >                  * we clean up any state on the server. We therefore
    >                  * record the lock call as having succeeded in order to
    >                  * ensure that locks_remove_posix() cleans it out when
    > -                * the process exits.
    > +                * the process exits. Make sure not to sleep if
    > +                * someone else holds the lock.
    >                  */
    > -               if (status == -EINTR || status == -ERESTARTSYS)
    > +               if (status == -EINTR || status == -ERESTARTSYS) {
    > +                       fl->fl_flags &= ~FL_SLEEP;
    >                         do_vfs_lock(filp, fl);
    > +               }
    >         } else
    >                 status = do_vfs_lock(filp, fl);
    >         unlock_kernel();
    >
    
    
    
    -- 
    Jesper Juhl <jesper.juhl@gmail.com>
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