linux-ext4 - Re: warning in ext4_journal_start

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Date:	Mon, 10 Mar 2014 15:57:09 -0400
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	Jan Kara <jack@...e.cz>, Matthew Rahtz <mrahtz@...itasystems.com>,
	linux-ext4@...r.kernel.org, linux-nfs@...r.kernel.org
Subject: Re: warning in ext4_journal_start_sb on filesystem freeze

On Mon, Mar 10, 2014 at 06:34:51AM -0700, Christoph Hellwig wrote:
> On Tue, Mar 04, 2014 at 02:04:42PM -0500, J. Bruce Fields wrote:
> > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > index 6d7be3f..eea5ad1 100644
> > --- a/fs/nfsd/vfs.c
> > +++ b/fs/nfsd/vfs.c
> > @@ -404,6 +404,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> >  	umode_t		ftype = 0;
> >  	__be32		err;
> >  	int		host_err;
> > +	bool		get_write_count;
> >  	int		size_change = 0;
> >  
> >  	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
> > @@ -411,10 +412,18 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> >  	if (iap->ia_valid & ATTR_SIZE)
> >  		ftype = S_IFREG;
> >  
> > +	/* Callers that do fh_verify should do the fh_want_write: */
> > +	get_write_count = !fhp->fh_dentry;
> 
> Eww, this is nasty.  Given that there are only 6 callers of nfsd_setattr
> in total, and only half of these might cause size changes I'd rather
> deal with this properly, e.g. by taking both the fh_verify into the
> callers.

Maybe so.

(Size is irrelevant, though, right?  Won't any setattr need an elevated
write count?)

--b.
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