linux-kernel - Re: [NFS] [PATCH 2/2] nfs4: on a O_EXCL OPEN make sure the SETATTR sets the fields holding the verifier

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Message-Id: <1181074300.7033.34.camel@heimdal.trondhjem.org>
Date:	Tue, 05 Jun 2007 16:11:40 -0400
From:	Trond Myklebust <trond.myklebust@....uio.no>
To:	Jeff Layton <jlayton@...hat.com>
Cc:	nfsv4@...ux-nfs.org, nfs@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [NFS] [PATCH 2/2] nfs4: on a O_EXCL OPEN make sure the SETATTR
	sets the fields holding the verifier

On Tue, 2007-06-05 at 15:35 -0400, Jeff Layton wrote:
> On Tue, 05 Jun 2007 14:13:02 -0400
> Trond Myklebust <trond.myklebust@....uio.no> wrote:
> 
> > On Tue, 2007-06-05 at 13:56 -0400, Jeff Layton wrote:
> > > The Linux NFS4 client simply skips over the bitmask in an O_EXCL open
> > > call and so it doesn't bother to reset any fields that may be holding
> > > the verifier. This patch has us save the first two words of the bitmask
> > > (which is all the current client has #defines for). The client then
> > > later checks this bitmask and turns on the appropriate flags in the
> > > sattr->ia_verify field for the following SETATTR call.
> > > 
> > > This patch only currently checks to see if the server used the atime
> > > and mtime slots for the verifier (which is what the Linux server uses
> > > for this). I'm not sure of what other fields the server could
> > > reasonably use, but adding checks for others should be trivial.
> > > 
> > > Signed-off-by: Jeff Layton <jlayton@...hat.com>
> > > 
> > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> > > index 8e46e3e..34ddd66 100644
> > > --- a/fs/nfs/nfs4proc.c
> > > +++ b/fs/nfs/nfs4proc.c
> > > @@ -955,6 +955,22 @@ static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, st
> > >  }
> > >  
> > >  /*
> > > + * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*
> > > + * fields corresponding to attributes that were used to store the verifier.
> > > + * Make sure we clobber those fields in the later setattr call
> > > + */
> > > +static inline void nfs4_exclusive_attrset (struct nfs4_opendata *opendata, struct iattr *sattr)
> > > +{
> > > +	if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_ACCESS) &&
> > > +	    !(sattr->ia_valid & ATTR_ATIME_SET))
> > > +		sattr->ia_valid |= ATTR_ATIME;
> > > +
> > > +	if ((opendata->o_res.attrset[1] & FATTR4_WORD1_TIME_MODIFY) &&
> > > +	    !(sattr->ia_valid & ATTR_MTIME_SET))
> > > +		sattr->ia_valid |= ATTR_MTIME;
> > > +}
> > > +
> > > +/*
> > >   * Returns a referenced nfs4_state
> > >   */
> > >  static int _nfs4_do_open(struct inode *dir, struct dentry *dentry, int flags, struct iattr *sattr, struct rpc_cred *cred, struct nfs4_state **res)
> > > @@ -985,6 +1001,9 @@ static int _nfs4_do_open(struct inode *dir, struct dentry *dentry, int flags, st
> > >  	if (status != 0)
> > >  		goto err_opendata_free;
> > >  
> > > +	if (opendata->o_arg.open_flags & O_EXCL)
> > > +		nfs4_exclusive_attrset(opendata, sattr);
> > > +
> > >  	status = -ENOMEM;
> > >  	state = nfs4_opendata_to_nfs4_state(opendata);
> > >  	if (state == NULL)
> > > @@ -1787,6 +1806,7 @@ nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
> > >  		status = nfs4_do_setattr(state->inode, &fattr, sattr, state);
> > >  		if (status == 0)
> > >  			nfs_setattr_update_inode(state->inode, sattr);
> > > +		nfs_refresh_inode(state->inode, &fattr);
> >                   ^^^^ should be nfs_post_op_update_inode() to ensure
> > that the attribute cache gets invalidated if the server fails to return
> > the post-op attributes.
> > 
> 
> It looks like nfs3_proc_create() uses nfs_refresh_inode in this spot (which was
> why I initially used one here). Should it also be changed to use
> nfs_post_op_update_inode(), or is it correct as-is?

nfs3_proc_create() also appears to be calling nfs_setattr_update_inode()
twice. I'll fix both issues in a separate patch.

Trond

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