1 files changed, 228 insertions, 100 deletions

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 956d5ddddf6..8c41b52da35 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -23,9 +23,13 @@
 #include <linux/debugfs.h>
 #include <linux/fsnotify.h>
 #include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/parser.h>
 #include <linux/magic.h>
 #include <linux/slab.h>
 
+#define DEBUGFS_DEFAULT_MODE	0700
+
 static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
 static bool debugfs_registered;
@@ -50,13 +54,11 @@ static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev
 			break;
 		case S_IFLNK:
 			inode->i_op = &debugfs_link_operations;
-			inode->i_fop = fops;
 			inode->i_private = data;
 			break;
 		case S_IFDIR:
 			inode->i_op = &simple_dir_inode_operations;
-			inode->i_fop = fops ? fops : &simple_dir_operations;
-			inode->i_private = data;
+			inode->i_fop = &simple_dir_operations;
 
 			/* directory inodes start off with i_nlink == 2
 			 * (for "." entry) */
@@ -87,13 +89,12 @@ static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
 	return error;
 }
 
-static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode,
-			 void *data, const struct file_operations *fops)
+static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	int res;
 
 	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
-	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
+	res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
 	if (!res) {
 		inc_nlink(dir);
 		fsnotify_mkdir(dir, dentry);
@@ -102,10 +103,10 @@ static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode,
 }
 
 static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
-			void *data, const struct file_operations *fops)
+			void *data)
 {
 	mode = (mode & S_IALLUGO) | S_IFLNK;
-	return debugfs_mknod(dir, dentry, mode, 0, data, fops);
+	return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
 }
 
 static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
@@ -125,11 +126,165 @@ static inline int debugfs_positive(struct dentry *dentry)
 	return dentry->d_inode && !d_unhashed(dentry);
 }
 
+struct debugfs_mount_opts {
+	kuid_t uid;
+	kgid_t gid;
+	umode_t mode;
+};
+
+enum {
+	Opt_uid,
+	Opt_gid,
+	Opt_mode,
+	Opt_err
+};
+
+static const match_table_t tokens = {
+	{Opt_uid, "uid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_mode, "mode=%o"},
+	{Opt_err, NULL}
+};
+
+struct debugfs_fs_info {
+	struct debugfs_mount_opts mount_opts;
+};
+
+static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
+{
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	int token;
+	kuid_t uid;
+	kgid_t gid;
+	char *p;
+
+	opts->mode = DEBUGFS_DEFAULT_MODE;
+
+	while ((p = strsep(&data, ",")) != NULL) {
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_uid:
+			if (match_int(&args[0], &option))
+				return -EINVAL;
+			uid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(uid))
+				return -EINVAL;
+			opts->uid = uid;
+			break;
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+				return -EINVAL;
+			gid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(gid))
+				return -EINVAL;
+			opts->gid = gid;
+			break;
+		case Opt_mode:
+			if (match_octal(&args[0], &option))
+				return -EINVAL;
+			opts->mode = option & S_IALLUGO;
+			break;
+		/*
+		 * We might like to report bad mount options here;
+		 * but traditionally debugfs has ignored all mount options
+		 */
+		}
+	}
+
+	return 0;
+}
+
+static int debugfs_apply_options(struct super_block *sb)
+{
+	struct debugfs_fs_info *fsi = sb->s_fs_info;
+	struct inode *inode = sb->s_root->d_inode;
+	struct debugfs_mount_opts *opts = &fsi->mount_opts;
+
+	inode->i_mode &= ~S_IALLUGO;
+	inode->i_mode |= opts->mode;
+
+	inode->i_uid = opts->uid;
+	inode->i_gid = opts->gid;
+
+	return 0;
+}
+
+static int debugfs_remount(struct super_block *sb, int *flags, char *data)
+{
+	int err;
+	struct debugfs_fs_info *fsi = sb->s_fs_info;
+
+	sync_filesystem(sb);
+	err = debugfs_parse_options(data, &fsi->mount_opts);
+	if (err)
+		goto fail;
+
+	debugfs_apply_options(sb);
+
+fail:
+	return err;
+}
+
+static int debugfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
+	struct debugfs_mount_opts *opts = &fsi->mount_opts;
+
+	if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+			   from_kuid_munged(&init_user_ns, opts->uid));
+	if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+			   from_kgid_munged(&init_user_ns, opts->gid));
+	if (opts->mode != DEBUGFS_DEFAULT_MODE)
+		seq_printf(m, ",mode=%o", opts->mode);
+
+	return 0;
+}
+
+static const struct super_operations debugfs_super_operations = {
+	.statfs		= simple_statfs,
+	.remount_fs	= debugfs_remount,
+	.show_options	= debugfs_show_options,
+};
+
 static int debug_fill_super(struct super_block *sb, void *data, int silent)
 {
 	static struct tree_descr debug_files[] = {{""}};
+	struct debugfs_fs_info *fsi;
+	int err;
+
+	save_mount_options(sb, data);
+
+	fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
+	sb->s_fs_info = fsi;
+	if (!fsi) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	err = debugfs_parse_options(data, &fsi->mount_opts);
+	if (err)
+		goto fail;
+
+	err  =  simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+	if (err)
+		goto fail;
 
-	return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+	sb->s_op = &debugfs_super_operations;
+
+	debugfs_apply_options(sb);
+
+	return 0;
+
+fail:
+	kfree(fsi);
+	sb->s_fs_info = NULL;
+	return err;
 }
 
 static struct dentry *debug_mount(struct file_system_type *fs_type,
@@ -145,14 +300,21 @@ static struct file_system_type debug_fs_type = {
 	.mount =	debug_mount,
 	.kill_sb =	kill_litter_super,
 };
+MODULE_ALIAS_FS("debugfs");
 
-static int debugfs_create_by_name(const char *name, umode_t mode,
-				  struct dentry *parent,
-				  struct dentry **dentry,
-				  void *data,
-				  const struct file_operations *fops)
+static struct dentry *__create_file(const char *name, umode_t mode,
+				    struct dentry *parent, void *data,
+				    const struct file_operations *fops)
 {
-	int error = 0;
+	struct dentry *dentry = NULL;
+	int error;
+
+	pr_debug("debugfs: creating file '%s'\n",name);
+
+	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
+			      &debugfs_mount_count);
+	if (error)
+		goto exit;
 
 	/* If the parent is not specified, we create it in the root.
 	 * We need the root dentry to do this, which is in the super 
@@ -162,30 +324,34 @@ static int debugfs_create_by_name(const char *name, umode_t mode,
 	if (!parent)
 		parent = debugfs_mount->mnt_root;
 
-	*dentry = NULL;
 	mutex_lock(&parent->d_inode->i_mutex);
-	*dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(*dentry)) {
+	dentry = lookup_one_len(name, parent, strlen(name));
+	if (!IS_ERR(dentry)) {
 		switch (mode & S_IFMT) {
 		case S_IFDIR:
-			error = debugfs_mkdir(parent->d_inode, *dentry, mode,
-					      data, fops);
+			error = debugfs_mkdir(parent->d_inode, dentry, mode);
+					      
 			break;
 		case S_IFLNK:
-			error = debugfs_link(parent->d_inode, *dentry, mode,
-					     data, fops);
+			error = debugfs_link(parent->d_inode, dentry, mode,
+					     data);
 			break;
 		default:
-			error = debugfs_create(parent->d_inode, *dentry, mode,
+			error = debugfs_create(parent->d_inode, dentry, mode,
 					       data, fops);
 			break;
 		}
-		dput(*dentry);
+		dput(dentry);
 	} else
-		error = PTR_ERR(*dentry);
+		error = PTR_ERR(dentry);
 	mutex_unlock(&parent->d_inode->i_mutex);
 
-	return error;
+	if (error) {
+		dentry = NULL;
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+	}
+exit:
+	return dentry;
 }
 
 /**
@@ -193,7 +359,7 @@ static int debugfs_create_by_name(const char *name, umode_t mode,
  * @name: a pointer to a string containing the name of the file to create.
  * @mode: the permission that the file should have.
  * @parent: a pointer to the parent dentry for this file.  This should be a
- *          directory dentry if set.  If this paramater is NULL, then the
+ *          directory dentry if set.  If this parameter is NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @data: a pointer to something that the caller will want to get to later
  *        on.  The inode.i_private pointer will point to this value on
@@ -218,25 +384,15 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
 				   const struct file_operations *fops)
 {
-	struct dentry *dentry = NULL;
-	int error;
-
-	pr_debug("debugfs: creating file '%s'\n",name);
-
-	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
-			      &debugfs_mount_count);
-	if (error)
-		goto exit;
-
-	error = debugfs_create_by_name(name, mode, parent, &dentry,
-				       data, fops);
-	if (error) {
-		dentry = NULL;
-		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
-		goto exit;
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+	case 0:
+		break;
+	default:
+		BUG();
 	}
-exit:
-	return dentry;
+
+	return __create_file(name, mode, parent, data, fops);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_file);
 
@@ -245,7 +401,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
  * @name: a pointer to a string containing the name of the directory to
  *        create.
  * @parent: a pointer to the parent dentry for this file.  This should be a
- *          directory dentry if set.  If this paramater is NULL, then the
+ *          directory dentry if set.  If this parameter is NULL, then the
  *          directory will be created in the root of the debugfs filesystem.
  *
  * This function creates a directory in debugfs with the given name.
@@ -260,8 +416,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
  */
 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 {
-	return debugfs_create_file(name, 
-				   S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+	return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
 				   parent, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(debugfs_create_dir);
@@ -271,7 +426,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_dir);
  * @name: a pointer to a string containing the name of the symbolic link to
  *        create.
  * @parent: a pointer to the parent dentry for this symbolic link.  This
- *          should be a directory dentry if set.  If this paramater is NULL,
+ *          should be a directory dentry if set.  If this parameter is NULL,
  *          then the symbolic link will be created in the root of the debugfs
  *          filesystem.
  * @target: a pointer to a string containing the path to the target of the
@@ -299,8 +454,7 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 	if (!link)
 		return NULL;
 
-	result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
-				     NULL);
+	result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
 	if (!result)
 		kfree(link);
 	return result;
@@ -351,7 +505,7 @@ void debugfs_remove(struct dentry *dentry)
 	struct dentry *parent;
 	int ret;
 
-	if (!dentry)
+	if (IS_ERR_OR_NULL(dentry))
 		return;
 
 	parent = dentry->d_parent;
@@ -380,10 +534,9 @@ EXPORT_SYMBOL_GPL(debugfs_remove);
  */
 void debugfs_remove_recursive(struct dentry *dentry)
 {
-	struct dentry *child;
-	struct dentry *parent;
+	struct dentry *child, *next, *parent;
 
-	if (!dentry)
+	if (IS_ERR_OR_NULL(dentry))
 		return;
 
 	parent = dentry->d_parent;
@@ -391,61 +544,36 @@ void debugfs_remove_recursive(struct dentry *dentry)
 		return;
 
 	parent = dentry;
+ down:
 	mutex_lock(&parent->d_inode->i_mutex);
+	list_for_each_entry_safe(child, next, &parent->d_subdirs, d_u.d_child) {
+		if (!debugfs_positive(child))
+			continue;
 
-	while (1) {
-		/*
-		 * When all dentries under "parent" has been removed,
-		 * walk up the tree until we reach our starting point.
-		 */
-		if (list_empty(&parent->d_subdirs)) {
-			mutex_unlock(&parent->d_inode->i_mutex);
-			if (parent == dentry)
-				break;
-			parent = parent->d_parent;
-			mutex_lock(&parent->d_inode->i_mutex);
-		}
-		child = list_entry(parent->d_subdirs.next, struct dentry,
-				d_u.d_child);
- next_sibling:
-
-		/*
-		 * If "child" isn't empty, walk down the tree and
-		 * remove all its descendants first.
-		 */
+		/* perhaps simple_empty(child) makes more sense */
 		if (!list_empty(&child->d_subdirs)) {
 			mutex_unlock(&parent->d_inode->i_mutex);
 			parent = child;
-			mutex_lock(&parent->d_inode->i_mutex);
-			continue;
+			goto down;
 		}
-		__debugfs_remove(child, parent);
-		if (parent->d_subdirs.next == &child->d_u.d_child) {
-			/*
-			 * Try the next sibling.
-			 */
-			if (child->d_u.d_child.next != &parent->d_subdirs) {
-				child = list_entry(child->d_u.d_child.next,
-						   struct dentry,
-						   d_u.d_child);
-				goto next_sibling;
-			}
-
-			/*
-			 * Avoid infinite loop if we fail to remove
-			 * one dentry.
-			 */
-			mutex_unlock(&parent->d_inode->i_mutex);
-			break;
-		}
-		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ up:
+		if (!__debugfs_remove(child, parent))
+			simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	}
 
-	parent = dentry->d_parent;
+	mutex_unlock(&parent->d_inode->i_mutex);
+	child = parent;
+	parent = parent->d_parent;
 	mutex_lock(&parent->d_inode->i_mutex);
-	__debugfs_remove(dentry, parent);
+
+	if (child != dentry) {
+		next = list_next_entry(child, d_u.d_child);
+		goto up;
+	}
+
+	if (!__debugfs_remove(child, parent))
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 	mutex_unlock(&parent->d_inode->i_mutex);
-	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 }
 EXPORT_SYMBOL_GPL(debugfs_remove_recursive);