Re: [PATCH] nfs: commit layouts in fdatasync

[Christoph Hellwig <hch@infradead.org>]

On Sun, May 04, 2014 at 11:56:24PM -0700, Christoph Hellwig wrote:
> ping?  This is a fairly serious data integrity issue for pnfs users.

ping^2

without this fdatasync and O_DSYNC writes on pnfs are more or less
noops, so at least getting a review would be helpful, nevermind
forwarding it to Linus and -stable.

> 
> On Mon, Apr 21, 2014 at 10:29:17AM -0700, Christoph Hellwig wrote:
> > >From fdatasync(2):
> > 
> >  "fdatasync() is similar to fsync(), but does not flush modified metadata
> >   unless that metadata is needed in order  to  allow  a  subsequent  data
> >   retrieval to be correctly handled."
> > 
> > We absolutely need to commit the layouts to be able to retrieve the data
> > in case either the client, the server or the storage subsystem go down.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > 
> > diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> > index 8de3407..464db9d 100644
> > --- a/fs/nfs/nfs4file.c
> > +++ b/fs/nfs/nfs4file.c
> > @@ -100,8 +100,7 @@ nfs4_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
> >  			break;
> >  		mutex_lock(&inode->i_mutex);
> >  		ret = nfs_file_fsync_commit(file, start, end, datasync);
> > -		if (!ret && !datasync)
> > -			/* application has asked for meta-data sync */
> > +		if (!ret)
> >  			ret = pnfs_layoutcommit_inode(inode, true);
> >  		mutex_unlock(&inode->i_mutex);
> >  		/*
> > --
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> ---end quoted text---
---end quoted text---