Re: [PATCH 04/35] whiteout/NFSD: Don't return information about whiteouts to userspace

["J. Bruce Fields" <bfields@fieldses.org>]

On Mon, Apr 19, 2010 at 02:37:41PM +0200, Jan Blunck wrote:
> On Fri, Apr 16, J. Bruce Fields wrote:
> 
> > Seems OK.  (Though is there any way we could avoid having to add the
> > check to every filldir callback?  Isn't the default going to be
> > disinterest in whiteouts?  How are we avoiding all the same checks in
> > the case of lookup?)
> > 
> 
> Bruce,
> 
> the alternative would be to include the check in the fs readdir()
> implementation, and therefore prevent the call of the filler. I think this
> patch would be even bigger.

OK, makes sense.

--b.

> 
> Jan
> 
> > --b.
> > 
> > On Thu, Apr 15, 2010 at 04:04:11PM -0700, Valerie Aurora wrote:
> > > From: Jan Blunck <jblunck@suse.de>
> > > 
> > > Userspace isn't ready for handling another file type, so silently drop
> > > whiteout directory entries before they leave the kernel.
> > > 
> > > Signed-off-by: Jan Blunck <jblunck@suse.de>
> > > Signed-off-by: David Woodhouse <dwmw2@infradead.org>
> > > Signed-off-by: Valerie Aurora <vaurora@redhat.com>
> > > Cc: linux-nfs@vger.kernel.org
> > > Cc: "J. Bruce Fields" <bfields@fieldses.org>
> > > Cc: Neil Brown <neilb@suse.de>
> > > ---
> > >  fs/compat.c       |    9 +++++++++
> > >  fs/nfsd/nfs3xdr.c |    5 +++++
> > >  fs/nfsd/nfs4xdr.c |    5 +++++
> > >  fs/nfsd/nfsxdr.c  |    4 ++++
> > >  fs/readdir.c      |    9 +++++++++
> > >  5 files changed, 32 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/fs/compat.c b/fs/compat.c
> > > index 00d90c2..624e1a5 100644
> > > --- a/fs/compat.c
> > > +++ b/fs/compat.c
> > > @@ -838,6 +838,9 @@ static int compat_fillonedir(void *__buf, const char *name, int namlen,
> > >  	struct compat_old_linux_dirent __user *dirent;
> > >  	compat_ulong_t d_ino;
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	if (buf->result)
> > >  		return -EINVAL;
> > >  	d_ino = ino;
> > > @@ -909,6 +912,9 @@ static int compat_filldir(void *__buf, const char *name, int namlen,
> > >  	compat_ulong_t d_ino;
> > >  	int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 2, sizeof(compat_long_t));
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	buf->error = -EINVAL;	/* only used if we fail.. */
> > >  	if (reclen > buf->count)
> > >  		return -EINVAL;
> > > @@ -998,6 +1004,9 @@ static int compat_filldir64(void * __buf, const char * name, int namlen, loff_t
> > >  	int reclen = ALIGN(jj + namlen + 1, sizeof(u64));
> > >  	u64 off;
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	buf->error = -EINVAL;	/* only used if we fail.. */
> > >  	if (reclen > buf->count)
> > >  		return -EINVAL;
> > > diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
> > > index 2a533a0..9b96f5a 100644
> > > --- a/fs/nfsd/nfs3xdr.c
> > > +++ b/fs/nfsd/nfs3xdr.c
> > > @@ -885,6 +885,11 @@ encode_entry(struct readdir_cd *ccd, const char *name, int namlen,
> > >  	int		elen;		/* estimated entry length in words */
> > >  	int		num_entry_words = 0;	/* actual number of words */
> > >  
> > > +	if (d_type == DT_WHT) {
> > > +		cd->common.err = nfs_ok;
> > > +		return 0;
> > > +	}
> > > +
> > >  	if (cd->offset) {
> > >  		u64 offset64 = offset;
> > >  
> > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> > > index 78c7e24..8839ba8 100644
> > > --- a/fs/nfsd/nfs4xdr.c
> > > +++ b/fs/nfsd/nfs4xdr.c
> > > @@ -2268,6 +2268,11 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
> > >  		return 0;
> > >  	}
> > >  
> > > +	if (d_type == DT_WHT) {
> > > +		cd->common.err = nfs_ok;
> > > +		return 0;
> > > +	}
> > > +
> > >  	if (cd->offset)
> > >  		xdr_encode_hyper(cd->offset, (u64) offset);
> > >  
> > > diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
> > > index 4ce005d..0e57d4b 100644
> > > --- a/fs/nfsd/nfsxdr.c
> > > +++ b/fs/nfsd/nfsxdr.c
> > > @@ -503,6 +503,10 @@ nfssvc_encode_entry(void *ccdv, const char *name,
> > >  			namlen, name, offset, ino);
> > >  	 */
> > >  
> > > +	if (d_type == DT_WHT) {
> > > +		cd->common.err = nfs_ok;
> > > +		return 0;
> > > +	}
> > >  	if (offset > ~((u32) 0)) {
> > >  		cd->common.err = nfserr_fbig;
> > >  		return -EINVAL;
> > > diff --git a/fs/readdir.c b/fs/readdir.c
> > > index 7723401..3a48491 100644
> > > --- a/fs/readdir.c
> > > +++ b/fs/readdir.c
> > > @@ -77,6 +77,9 @@ static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset
> > >  	struct old_linux_dirent __user * dirent;
> > >  	unsigned long d_ino;
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	if (buf->result)
> > >  		return -EINVAL;
> > >  	d_ino = ino;
> > > @@ -154,6 +157,9 @@ static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
> > >  	unsigned long d_ino;
> > >  	int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 2, sizeof(long));
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	buf->error = -EINVAL;	/* only used if we fail.. */
> > >  	if (reclen > buf->count)
> > >  		return -EINVAL;
> > > @@ -239,6 +245,9 @@ static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
> > >  	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
> > >  	int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 1, sizeof(u64));
> > >  
> > > +	if (d_type == DT_WHT)
> > > +		return 0;
> > > +
> > >  	buf->error = -EINVAL;	/* only used if we fail.. */
> > >  	if (reclen > buf->count)
> > >  		return -EINVAL;
> > > -- 
> > > 1.6.3.3
> > >