1 files changed, 49 insertions, 33 deletions

diff --git a/fs/libfs.c b/fs/libfs.c
index 7e52e77692ec..c9b2850c0f7c 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -17,6 +17,8 @@
 #include <linux/exportfs.h>
 #include <linux/writeback.h>
 #include <linux/buffer_head.h> /* sync_mapping_buffers */
+#include <linux/fs_context.h>
+#include <linux/pseudo_fs.h>
 
 #include <linux/uaccess.h>
 
@@ -236,34 +238,22 @@ static const struct super_operations simple_super_operations = {
 	.statfs		= simple_statfs,
 };
 
-/*
- * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
- * will never be mountable)
- */
-struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
-	const struct super_operations *ops, const struct xattr_handler **xattr,
-	const struct dentry_operations *dops, unsigned long magic)
+static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc)
 {
-	struct super_block *s;
-	struct dentry *dentry;
+	struct pseudo_fs_context *ctx = fc->fs_private;
 	struct inode *root;
-	struct qstr d_name = QSTR_INIT(name, strlen(name));
-
-	s = sget_userns(fs_type, NULL, set_anon_super, SB_KERNMOUNT|SB_NOUSER,
-			&init_user_ns, NULL);
-	if (IS_ERR(s))
-		return ERR_CAST(s);
 
 	s->s_maxbytes = MAX_LFS_FILESIZE;
 	s->s_blocksize = PAGE_SIZE;
 	s->s_blocksize_bits = PAGE_SHIFT;
-	s->s_magic = magic;
-	s->s_op = ops ? ops : &simple_super_operations;
-	s->s_xattr = xattr;
+	s->s_magic = ctx->magic;
+	s->s_op = ctx->ops ?: &simple_super_operations;
+	s->s_xattr = ctx->xattr;
 	s->s_time_gran = 1;
 	root = new_inode(s);
 	if (!root)
-		goto Enomem;
+		return -ENOMEM;
+
 	/*
 	 * since this is the first inode, make it number 1. New inodes created
 	 * after this must take care not to collide with it (by passing
@@ -272,22 +262,48 @@ struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
 	root->i_ino = 1;
 	root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
 	root->i_atime = root->i_mtime = root->i_ctime = current_time(root);
-	dentry = __d_alloc(s, &d_name);
-	if (!dentry) {
-		iput(root);
-		goto Enomem;
+	s->s_root = d_make_root(root);
+	if (!s->s_root)
+		return -ENOMEM;
+	s->s_d_op = ctx->dops;
+	return 0;
+}
+
+static int pseudo_fs_get_tree(struct fs_context *fc)
+{
+	return get_tree_nodev(fc, pseudo_fs_fill_super);
+}
+
+static void pseudo_fs_free(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations pseudo_fs_context_ops = {
+	.free		= pseudo_fs_free,
+	.get_tree	= pseudo_fs_get_tree,
+};
+
+/*
+ * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
+ * will never be mountable)
+ */
+struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
+					unsigned long magic)
+{
+	struct pseudo_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL);
+	if (likely(ctx)) {
+		ctx->magic = magic;
+		fc->fs_private = ctx;
+		fc->ops = &pseudo_fs_context_ops;
+		fc->sb_flags |= SB_NOUSER;
+		fc->global = true;
 	}
-	d_instantiate(dentry, root);
-	s->s_root = dentry;
-	s->s_d_op = dops;
-	s->s_flags |= SB_ACTIVE;
-	return dget(s->s_root);
-
-Enomem:
-	deactivate_locked_super(s);
-	return ERR_PTR(-ENOMEM);
+	return ctx;
 }
-EXPORT_SYMBOL(mount_pseudo_xattr);
+EXPORT_SYMBOL(init_pseudo);
 
 int simple_open(struct inode *inode, struct file *file)
 {