mount_pseudo(): drop 'name' argument, switch to d_make_root()

Once upon a time we used to set ->d_name of e.g. pipefs root
so that d_path() on pipes would work.  These days it's
completely pointless - dentries of pipes are not even connected
to pipefs root.  However, mount_pseudo() had set the root
dentry name (passed as the second argument) and callers
kept inventing names to pass to it.  Including those that
didn't *have* any non-root dentries to start with...

All of that had been pointless for about 8 years now; it's
time to get rid of that cargo-culting...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 10 insertions, 17 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 3490d1fa0e16..09bc35fa6810 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -252,8 +252,7 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 static struct dentry *aio_mount(struct file_system_type *fs_type,
 				int flags, const char *dev_name, void *data)
 {
-	struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, NULL,
-					   AIO_RING_MAGIC);
+	struct dentry *root = mount_pseudo(fs_type, NULL, NULL, AIO_RING_MAGIC);
 
 	if (!IS_ERR(root))
 		root->d_sb->s_iflags |= SB_I_NOEXEC;
diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 91262c34b797..644d0837aafe 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -41,8 +41,8 @@ static const struct dentry_operations anon_inodefs_dentry_operations = {
 static struct dentry *anon_inodefs_mount(struct file_system_type *fs_type,
 				int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "anon_inode:", NULL,
-			&anon_inodefs_dentry_operations, ANON_INODE_FS_MAGIC);
+	return mount_pseudo(fs_type, NULL, &anon_inodefs_dentry_operations,
+			    ANON_INODE_FS_MAGIC);
 }
 
 static struct file_system_type anon_inode_fs_type = {
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0f7552a87d54..3143da7b0998 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -837,7 +837,7 @@ static struct dentry *bd_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
 	struct dentry *dent;
-	dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC);
+	dent = mount_pseudo(fs_type, &bdev_sops, NULL, BDEVFS_MAGIC);
 	if (!IS_ERR(dent))
 		dent->d_sb->s_iflags |= SB_I_CGROUPWB;
 	return dent;
diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
index 9238fd4f1734..6da54323eaf8 100644
--- a/fs/btrfs/tests/btrfs-tests.c
+++ b/fs/btrfs/tests/btrfs-tests.c
@@ -36,7 +36,7 @@ static struct dentry *btrfs_test_mount(struct file_system_type *fs_type,
 				       int flags, const char *dev_name,
 				       void *data)
 {
-	return mount_pseudo(fs_type, "btrfs_test:", &btrfs_test_super_ops,
+	return mount_pseudo(fs_type, &btrfs_test_super_ops,
 			    NULL, BTRFS_TEST_MAGIC);
 }
 
diff --git a/fs/libfs.c b/fs/libfs.c
index 4b59b1816efb..030e545f586e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -239,14 +239,12 @@ static const struct super_operations simple_super_operations = {
  * 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,
+struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type,
 	const struct super_operations *ops, const struct xattr_handler **xattr,
 	const struct dentry_operations *dops, unsigned long magic)
 {
 	struct super_block *s;
-	struct dentry *dentry;
 	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);
@@ -271,13 +269,9 @@ 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);
+	s->s_root = d_make_root(root);
+	if (!s->s_root)
 		goto Enomem;
-	}
-	d_instantiate(dentry, root);
-	s->s_root = dentry;
 	s->s_d_op = dops;
 	s->s_flags |= SB_ACTIVE;
 	return dget(s->s_root);
diff --git a/fs/nsfs.c b/fs/nsfs.c
index e3bf08c5af41..b3c49ddc0f85 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -261,7 +261,7 @@ static const struct super_operations nsfs_ops = {
 static struct dentry *nsfs_mount(struct file_system_type *fs_type,
 			int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "nsfs:", &nsfs_ops,
+	return mount_pseudo(fs_type, &nsfs_ops,
 			&ns_dentry_operations, NSFS_MAGIC);
 }
 static struct file_system_type nsfs = {
diff --git a/fs/pipe.c b/fs/pipe.c
index 41065901106b..99a023730e6f 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -1185,7 +1185,7 @@ static const struct super_operations pipefs_ops = {
 static struct dentry *pipefs_mount(struct file_system_type *fs_type,
 			 int flags, const char *dev_name, void *data)
 {
-	return mount_pseudo(fs_type, "pipe:", &pipefs_ops,
+	return mount_pseudo(fs_type, &pipefs_ops,
 			&pipefs_dentry_operations, PIPEFS_MAGIC);
 }