[PATCH] knfsd: fix setattr-on-symlink error return

This is a somewhat cosmetic fix to keep the SpecFS validation test from
complaining.

SpecFS want's to try chmod on symlinks, and ext3 and reiser (at least) return
ENOTSUPP.

Probably both sides are being silly, but it is easiest to simply make it a
non-issue and filter out chmod requests on symlinks at the nfsd level.
Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/vfs.c

@@ -254,12 +254,19 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 
 	/* Get inode */
 	err = fh_verify(rqstp, fhp, ftype, accmode);
-	if (err || !iap->ia_valid)
+	if (err)
 		goto out;
 
 	dentry = fhp->fh_dentry;
 	inode = dentry->d_inode;
 
+	/* Ignore any mode updates on symlinks */
+	if (S_ISLNK(inode->i_mode))
+		iap->ia_valid &= ~ATTR_MODE;
+
+	if (!iap->ia_valid)
+		goto out;
+
 	/* NFSv2 does not differentiate between "set-[ac]time-to-now"
 	 * which only requires access, and "set-[ac]time-to-X" which
 	 * requires ownership.