kernfs: implement kernfs_syscall_ops->remount_fs() and ->show_options()

Add two super_block related syscall callbacks ->remount_fs() and
->show_options() to kernfs_syscall_ops.  These simply forward the
matching super_operations.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 0d6ce89..70cc698 100644 (file)
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -19,10 +19,33 @@
 
 struct kmem_cache *kernfs_node_cache;
 
+static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+       struct kernfs_root *root = kernfs_info(sb)->root;
+       struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+       if (scops && scops->remount_fs)
+               return scops->remount_fs(root, flags, data);
+       return 0;
+}
+
+static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
+{
+       struct kernfs_root *root = kernfs_root(dentry->d_fsdata);
+       struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+       if (scops && scops->show_options)
+               return scops->show_options(sf, root);
+       return 0;
+}
+
 static const struct super_operations kernfs_sops = {
        .statfs         = simple_statfs,
        .drop_inode     = generic_delete_inode,
        .evict_inode    = kernfs_evict_inode,
+
+       .remount_fs     = kernfs_sop_remount_fs,
+       .show_options   = kernfs_sop_show_options,
 };
 
 static int kernfs_fill_super(struct super_block *sb)

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 5ddc474..5d5b7e9 100644 (file)
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -115,6 +115,9 @@ struct kernfs_node {
  * kernfs_node parameter.
  */
 struct kernfs_syscall_ops {
+       int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
+       int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
+
        int (*mkdir)(struct kernfs_node *parent, const char *name,
                     umode_t mode);
        int (*rmdir)(struct kernfs_node *kn);