coda: deal correctly with allocation failure from coda_cnode_makectl()

lookup should fail with ENOMEM, not silently make dentry negative.
Switched to saner calling conventions, while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/coda/cnode.c

@@ -156,19 +156,16 @@ struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb)
 }
 
 /* the CONTROL inode is made without asking attributes from Venus */
-int coda_cnode_makectl(struct inode **inode, struct super_block *sb)
+struct inode *coda_cnode_makectl(struct super_block *sb)
 {
-	int error = -ENOMEM;
-
-	*inode = new_inode(sb);
-	if (*inode) {
-		(*inode)->i_ino = CTL_INO;
-		(*inode)->i_op = &coda_ioctl_inode_operations;
-		(*inode)->i_fop = &coda_ioctl_operations;
-		(*inode)->i_mode = 0444;
-		error = 0;
+	struct inode *inode = new_inode(sb);
+	if (inode) {
+		inode->i_ino = CTL_INO;
+		inode->i_op = &coda_ioctl_inode_operations;
+		inode->i_fop = &coda_ioctl_operations;
+		inode->i_mode = 0444;
+		return inode;
 	}
-
-	return error;
+	return ERR_PTR(-ENOMEM);
 }
 

fs/coda/coda_fs_i.h

@@ -51,7 +51,7 @@ struct coda_file_info {
 
 int coda_cnode_make(struct inode **, struct CodaFid *, struct super_block *);
 struct inode *coda_iget(struct super_block *sb, struct CodaFid *fid, struct coda_vattr *attr);
-int coda_cnode_makectl(struct inode **inode, struct super_block *sb);
+struct inode *coda_cnode_makectl(struct super_block *sb);
 struct inode *coda_fid_to_inode(struct CodaFid *fid, struct super_block *sb);
 void coda_replace_fid(struct inode *, struct CodaFid *, struct CodaFid *);
 

fs/coda/dir.c

@@ -111,7 +111,7 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struc
 
 	/* control object, create inode on the fly */
 	if (coda_isroot(dir) && coda_iscontrol(name, length)) {
-		error = coda_cnode_makectl(&inode, dir->i_sb);
+		inode = coda_cnode_makectl(dir->i_sb);
 		type = CODA_NOCACHE;
 		goto exit;
 	}
@@ -125,7 +125,7 @@ static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, struc
 		return ERR_PTR(error);
 
 exit:
-	if (inode && (type & CODA_NOCACHE))
+	if (inode && !IS_ERR(inode) && (type & CODA_NOCACHE))
 		coda_flag_inode(inode, C_VATTR | C_PURGE);
 
 	return d_splice_alias(inode, entry);