nfsd: make sure to balance get/put_write_access

commit 987da479 upstream.

Use a straight goto error label style in nfsd_setattr to make sure
we always do the put_write_access call after we got it earlier.

Note that the we have been failing to do that in the case
nfsd_break_lease() returns an error, a bug introduced into 2.6.38 with
6a76bebe "nfsd4: break lease on nfsd
setattr".
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
[bwh: Backported to 3.2: notify_change() takes only 2 arguments]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

fs/nfsd/vfs.c

@@ -443,27 +443,28 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 
 	iap->ia_valid |= ATTR_CTIME;
 
-	err = nfserr_notsync;
-	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
-		host_err = nfsd_break_lease(inode);
-		if (host_err)
-			goto out_nfserr;
-		fh_lock(fhp);
-
-		host_err = notify_change(dentry, iap);
-		err = nfserrno(host_err);
-		fh_unlock(fhp);
+	if (check_guard && guardtime != inode->i_ctime.tv_sec) {
+		err = nfserr_notsync;
+		goto out_put_write_access;
 	}
+
+	host_err = nfsd_break_lease(inode);
+	if (host_err)
+		goto out_put_write_access_nfserror;
+
+	fh_lock(fhp);
+	host_err = notify_change(dentry, iap);
+	fh_unlock(fhp);
+
+out_put_write_access_nfserror:
+	err = nfserrno(host_err);
+out_put_write_access:
 	if (size_change)
 		put_write_access(inode);
 	if (!err)
 		commit_metadata(fhp);
 out:
 	return err;
-
-out_nfserr:
-	err = nfserrno(host_err);
-	goto out;
 }
 
 #if defined(CONFIG_NFSD_V2_ACL) || \