new primitive: vfs_mkobj()

Similar to vfs_create(), but with caller-supplied callback (and
argument for it) to be used instead of ->create().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2898,6 +2898,27 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 }
 EXPORT_SYMBOL(vfs_create);
 
+int vfs_mkobj(struct dentry *dentry, umode_t mode,
+		int (*f)(struct dentry *, umode_t, void *),
+		void *arg)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	int error = may_create(dir, dentry);
+	if (error)
+		return error;
+
+	mode &= S_IALLUGO;
+	mode |= S_IFREG;
+	error = security_inode_create(dir, dentry, mode);
+	if (error)
+		return error;
+	error = f(dentry, mode, arg);
+	if (!error)
+		fsnotify_create(dir, dentry);
+	return error;
+}
+EXPORT_SYMBOL(vfs_mkobj);
+
 bool may_open_dev(const struct path *path)
 {
 	return !(path->mnt->mnt_flags & MNT_NODEV) &&

include/linux/fs.h

@@ -1608,6 +1608,10 @@ extern int vfs_whiteout(struct inode *, struct dentry *);
 extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,
 				  int open_flag);
 
+int vfs_mkobj(struct dentry *, umode_t,
+		int (*f)(struct dentry *, umode_t, void *),
+		void *);
+
 /*
  * VFS file helper functions.
  */