vfs: remove some unused old mount api code

Remove reconfigure_single, mount_single, and compare_single now
that no users remain.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Link: https://lore.kernel.org/r/20250205213931.74614-5-sandeen@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Eric Sandeen

fs/super.c

@@ -1737,61 +1737,6 @@ struct dentry *mount_nodev(struct file_system_type *fs_type,
 }
 EXPORT_SYMBOL(mount_nodev);
 
-int reconfigure_single(struct super_block *s,
-		       int flags, void *data)
-{
-	struct fs_context *fc;
-	int ret;
-
-	/* The caller really need to be passing fc down into mount_single(),
-	 * then a chunk of this can be removed.  [Bollocks -- AV]
-	 * Better yet, reconfiguration shouldn't happen, but rather the second
-	 * mount should be rejected if the parameters are not compatible.
-	 */
-	fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);
-	if (IS_ERR(fc))
-		return PTR_ERR(fc);
-
-	ret = parse_monolithic_mount_data(fc, data);
-	if (ret < 0)
-		goto out;
-
-	ret = reconfigure_super(fc);
-out:
-	put_fs_context(fc);
-	return ret;
-}
-
-static int compare_single(struct super_block *s, void *p)
-{
-	return 1;
-}
-
-struct dentry *mount_single(struct file_system_type *fs_type,
-	int flags, void *data,
-	int (*fill_super)(struct super_block *, void *, int))
-{
-	struct super_block *s;
-	int error;
-
-	s = sget(fs_type, compare_single, set_anon_super, flags, NULL);
-	if (IS_ERR(s))
-		return ERR_CAST(s);
-	if (!s->s_root) {
-		error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
-		if (!error)
-			s->s_flags |= SB_ACTIVE;
-	} else {
-		error = reconfigure_single(s, flags, data);
-	}
-	if (unlikely(error)) {
-		deactivate_locked_super(s);
-		return ERR_PTR(error);
-	}
-	return dget(s->s_root);
-}
-EXPORT_SYMBOL(mount_single);
-
 /**
  * vfs_get_tree - Get the mountable root
  * @fc: The superblock configuration context.

include/linux/fs.h

@@ -2641,9 +2641,6 @@ static inline bool is_mgtime(const struct inode *inode)
 extern struct dentry *mount_bdev(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data,
 	int (*fill_super)(struct super_block *, void *, int));
-extern struct dentry *mount_single(struct file_system_type *fs_type,
-	int flags, void *data,
-	int (*fill_super)(struct super_block *, void *, int));
 extern struct dentry *mount_nodev(struct file_system_type *fs_type,
 	int flags, void *data,
 	int (*fill_super)(struct super_block *, void *, int));

include/linux/fs_context.h

@@ -144,8 +144,6 @@ extern void put_fs_context(struct fs_context *fc);
 extern int vfs_parse_fs_param_source(struct fs_context *fc,
 				     struct fs_parameter *param);
 extern void fc_drop_locked(struct fs_context *fc);
-int reconfigure_single(struct super_block *s,
-		       int flags, void *data);
 
 extern int get_tree_nodev(struct fs_context *fc,
 			 int (*fill_super)(struct super_block *sb,