[linux-lvm] Re: DQUOT_SYNC undefined in XFS CVS kernel (was: Can't build CVS kernels of 20020321 & 20020327)

[Nathan Scott]

On Fri, Mar 29, 2002 at 10:26:41PM +1000, Adrian Head wrote:
> I have also run into the XFS CVS kernel compile failing because of an 
> undefined DQUOT_SYNC.  
> 
> Using the information given by Nathan I have tracked down the offending patch 
> that causes the problems.  In my case it was the LVM VFS-lock patch from the 
> Sistina LVM project.  What they seem to do is use DQUOT_SYNC to force the 
> writing of cached Quota infomation before they lock the VFS during snapshot 
> creation.  It would also seem that EVMS does the same thing.  

Aha, thanks for tracking this down Adrian.

> I expect that the XFS CVS kernel tree is actually ahead of the standard 
> 2.4.18 kernel tree in this respect so we'll have to wait until 2.4.19 is 
> released with the updated API's before other projects update their kernel 
> patches.

Yes, the XFS trees contain all of the quota patches from:
ftp://atrey.karlin.mff.cuni.cz/pub/local/jack/quota/v2.4/

I wouldn't expect these patches to be in 2.4.19 -- they are
not in 2.5 yet and I think Jan is concentrating on that step
first.

> Grep'ing through the kernel I have not been able to find any comments or 
> explanations regarding this - so I have assumed that DQUOT_SYNC can be 
> changed to DQUOT_SYNC_DEV without problems.  

Yes, by my understanding of the VFS quota subsystem that would
be the correct thing to do.

> After making that change the kernel compiles cleanly and boots.  I'm unsure 
> as yet if I have done the correct thing here.  Hopefuly someone will be able 
> to help us out and correct me if I'm incorrect.

I believe your change is correct, I've CC'd Jan in case there is
anything that I've overlooked.

cheers.


> The offending part of the VF-lock patch follows below:
> 
> Index: linus.21/fs/buffer.c
> --- linus.21/fs/buffer.c Mon, 28 Jan 2002 09:51:50 -0500 root 
> (linux/i/45_buffer.c 1.5.2.6 644)
> +++ linus.21(w)/fs/buffer.c Mon, 28 Jan 2002 11:54:36 -0500 root 
> (linux/i/45_buffer.c 1.5.2.6 644)
> @@ -361,6 +361,34 @@
>         fsync_dev(dev);
>  }
> 
> +int fsync_dev_lockfs(kdev_t dev)
> +{
> +       /* you are not allowed to try locking all the filesystems
> +       ** on the system, your chances of getting through without
> +       ** total deadlock are slim to none.
> +       */
> +       if (!dev)
> +               return fsync_dev(dev) ;
> +
> +       sync_buffers(dev, 0);
> +
> +       lock_kernel();
> +       /* note, the FS might need to start transactions to
> +       ** sync the inodes, or the quota, no locking until
> +       ** after these are done
> +       */
> +       sync_inodes(dev);
> +       DQUOT_SYNC(dev);   
>          ^<====  ****All I did was to change this to DQUOT_SYNC_DEV(dev);****
> +       /* if inodes or quotas could be dirtied during the
> +       ** sync_supers_lockfs call, the FS is responsible for getting
> +       ** them on disk, without deadlocking against the lock
> +       */
> +       sync_supers_lockfs(dev) ;
> +       unlock_kernel();
> +
> +       return sync_buffers(dev, 1) ;
> +}
> +
>  asmlinkage long sys_sync(void)
>  {
>         fsync_dev(0);
> 
> 
> On Thu, 28 Mar 2002 07:30, Nathan Scott wrote:
> > Hello,
> >
> > On Wed, Mar 27, 2002 at 09:45:48AM +0100, Bas wrote:
> > > Hi,
> > >
> > > It's not possible for me to build the kernel mentioned above. I saw the
> > > new qouta options and suspect it has something to do with it, but I'm not
> > > sure.
> > >
> > > Building everything goes fine, but at the end of the run it's not able to
> > > produce a kernel because of DQUOT_SYNC. I don't have the exact error
> > > here.
> >
> > Hmm... 20020327 - that's yesterday.  DQUOT_SYNC doesn't appear in
> > the source at all anymore (for awhile now), so I suspect the problem
> > must be at your end.  Try getting a fresh CVS copy and/or "make clean".
> > [ The other patches you mentioned should not have anything to do with
> > this problem. ]
> >
> > $ find . -type f | xargs fgrep DQUOT_SYNC
> > ./fs/buffer.c:  DQUOT_SYNC_SB(sb);
> > ./fs/buffer.c:  DQUOT_SYNC_DEV(dev);
> > ./include/linux/quotaops.h:#define DQUOT_SYNC_DEV(dev) 
> > sync_dquots_dev(dev, -1) ./include/linux/quotaops.h:#define
> > DQUOT_SYNC_SB(sb)    sync_dquots_sb(sb, -1)
> > ./include/linux/quotaops.h:#define DQUOT_SYNC_DEV(dev)                  do
> > { } while(0) ./include/linux/quotaops.h:#define DQUOT_SYNC_SB(sb)          
> >          do { } while(0) $
> >
> > FWIW, DQUOT_SYNC used to come from include/linux/quotaops.h
> > too, and its definition was also dependent on CONFIG_QUOTA.
> > The reason you'd be getting an unresolved symbol would be a
> > file referencing DQUOT_SYNC wasn't #include'ing quotaops.h;
> > but thats all by-the-by - the real problem is related to the
> > source you're using I suspect - it certainly doesn't match
> > CVS of yesterday.
> >
> > cheers.
> 
> -- 
> Adrian Head
> 
> (Public Key available on request.)

-- 
Nathan