debugfs mount options

index d38c88f..5af9658 100644
@@ -21,8 +21,10 @@
 #include <linux/kobject.h>
 #include <linux/namei.h>
 #include <linux/debugfs.h>
+#include <linux/parser.h>
 #include <linux/fsnotify.h>
 #include <linux/string.h>
+#include <linux/seq_file.h>
 #include <linux/magic.h>
 #include <linux/slab.h>
 

@@ -30,6 +32,9 @@ static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
 static bool debugfs_registered;
 
+unsigned int debugfs_umask;
+gid_t debugfs_gid;
+
 static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev,
 				       void *data, const struct file_operations *fops)
 

@@ -63,8 +68,10 @@ static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t d
 			inc_nlink(inode);
 			break;
 		}
+		inode->i_mode &= ~(0777 & debugfs_umask);
+		inode->i_gid = debugfs_gid;
 	}
-	return inode; 
+	return inode;
 }
 
 /* SMP-safe */

@@ -125,11 +132,85 @@ static inline int debugfs_positive(struct dentry *dentry)
 	return dentry->d_inode && !d_unhashed(dentry);
 }
 
+enum {
+	Opt_gid, Opt_umask, Opt_err
+};
+
+static const match_table_t debug_tokens = {
+	{Opt_gid, "gid=%u"},
+	{Opt_umask, "umask=%o"},
+	{Opt_err, NULL},
+};
+
+static int debug_parse_options(char *options, struct super_block *sb)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, debug_tokens, args);
+		switch (token) {
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+				return 0;
+			debugfs_gid = option;
+			break;
+		case Opt_umask:
+			if (match_octal(&args[0], &option))
+				return 0;
+			debugfs_umask = option;
+			break;
+		default:
+			pr_err("debugfs: unrecognized mount option \"%s\" "
+			       "or missing value", p);
+			return 0;
+		}
+	}
+	return 1;
+}
+
+static int debug_remount_fs(struct super_block *sb, int *flags, char *options)
+{
+	if (debug_parse_options(options, sb))
+		return 0;
+	else
+		return -EINVAL;
+}
+
+int debug_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+	if (debugfs_umask)
+		seq_printf(seq, ",umask=%o", debugfs_umask);
+	if (debugfs_gid)
+		seq_printf(seq, ",gid=%lu", (unsigned long)debugfs_gid);
+	return 0;
+}
+
+static const struct super_operations debug_super_operations = {
+	.statfs		= simple_statfs,
+	.remount_fs	= debug_remount_fs,
+	.show_options   = debug_show_options,
+};
+
 static int debug_fill_super(struct super_block *sb, void *data, int silent)
 {
 	static struct tree_descr debug_files[] = {{""}};
+	int err;
+
+	if (!debug_parse_options(data, sb))
+		return -EINVAL;
 
-	return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+	sb->s_op = &debug_super_operations;
+	err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+	return err;
 }
 
 static struct dentry *debug_mount(struct file_system_type *fs_type,