fuse: clean up return in fuse_dentry_revalidate()

On errors unrelated to the filesystem's state (ENOMEM, ENOTCONN) return the
error itself from ->d_revalidate() insted of returning zero (invalid).

Also make a common label for invalidating the dentry.  This will be used by
the next patch.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/fuse/dir.c

@@ -182,10 +182,11 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 	struct inode *inode;
 	struct dentry *parent;
 	struct fuse_conn *fc;
+	int ret;
 
 	inode = ACCESS_ONCE(entry->d_inode);
 	if (inode && is_bad_inode(inode))
-		return 0;
+		goto invalid;
 	else if (fuse_dentry_time(entry) < get_jiffies_64()) {
 		int err;
 		struct fuse_entry_out outarg;
@@ -195,20 +196,23 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 
 		/* For negative dentries, always do a fresh lookup */
 		if (!inode)
-			return 0;
+			goto invalid;
 
+		ret = -ECHILD;
 		if (flags & LOOKUP_RCU)
-			return -ECHILD;
+			goto out;
 
 		fc = get_fuse_conn(inode);
 		req = fuse_get_req_nopages(fc);
+		ret = PTR_ERR(req);
 		if (IS_ERR(req))
-			return 0;
+			goto out;
 
 		forget = fuse_alloc_forget();
 		if (!forget) {
 			fuse_put_request(fc, req);
-			return 0;
+			ret = -ENOMEM;
+			goto out;
 		}
 
 		attr_version = fuse_get_attr_version(fc);
@@ -227,15 +231,15 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 			struct fuse_inode *fi = get_fuse_inode(inode);
 			if (outarg.nodeid != get_node_id(inode)) {
 				fuse_queue_forget(fc, forget, outarg.nodeid, 1);
-				return 0;
+				goto invalid;
 			}
 			spin_lock(&fc->lock);
 			fi->nlookup++;
 			spin_unlock(&fc->lock);
 		}
 		kfree(forget);
 		if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
-			return 0;
+			goto invalid;
 
 		fuse_change_attributes(inode, &outarg.attr,
 				       entry_attr_timeout(&outarg),
@@ -249,7 +253,13 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 			dput(parent);
 		}
 	}
-	return 1;
+	ret = 1;
+out:
+	return ret;
+
+invalid:
+	ret = 0;
+	goto out;
 }
 
 static int invalid_nodeid(u64 nodeid)