Subject: [PATCH 8/8] tracefs: switch to simplefs inode creation API

From: Emanuele Giuseppe Esposito <[email-masked]>
Date: Tue, 14 Apr 2020 14:43:02 +0200

There is no semantic change intended; the code in the simplefs.c functions in
fact was derived from debugfs and tracefs code.

Signed-off-by: Emanuele Giuseppe Esposito <[email-masked]>
---
 fs/tracefs/inode.c | 86 ++++------------------------------------------
 1 file changed, 7 insertions(+), 79 deletions(-)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index a30837a8e1d4..69e2215c797b 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -298,57 +298,6 @@ static struct file_system_type trace_fs_type = {
 };
 MODULE_ALIAS_FS("tracefs");
 
-static struct dentry *start_creating(const char *name, struct dentry *parent)
-{
-	struct dentry *dentry;
-	int error;
-
-	pr_debug("tracefs: creating file '%s'\n",name);
-
-	error = simple_pin_fs(&tracefs, &trace_fs_type);
-	if (error)
-		return ERR_PTR(error);
-
-	/* 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
-	 * block. A pointer to that is in the struct vfsmount that we
-	 * have around.
-	 */
-	if (!parent)
-		parent = tracefs.mount->mnt_root;
-
-	inode_lock(parent->d_inode);
-	if (unlikely(IS_DEADDIR(parent->d_inode)))
-		dentry = ERR_PTR(-ENOENT);
-	else
-		dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(dentry) && dentry->d_inode) {
-		dput(dentry);
-		dentry = ERR_PTR(-EEXIST);
-	}
-
-	if (IS_ERR(dentry)) {
-		inode_unlock(parent->d_inode);
-		simple_release_fs(&tracefs);
-	}
-
-	return dentry;
-}
-
-static struct dentry *failed_creating(struct dentry *dentry)
-{
-	inode_unlock(dentry->d_parent->d_inode);
-	dput(dentry);
-	simple_release_fs(&tracefs);
-	return NULL;
-}
-
-static struct dentry *end_creating(struct dentry *dentry)
-{
-	inode_unlock(dentry->d_parent->d_inode);
-	return dentry;
-}
-
 /**
  * tracefs_create_file - create a file in the tracefs filesystem
  * @name: a pointer to a string containing the name of the file to create.
@@ -385,49 +334,28 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
 	if (security_locked_down(LOCKDOWN_TRACEFS))
 		return NULL;
 
-	if (!(mode & S_IFMT))
-		mode |= S_IFREG;
-	BUG_ON(!S_ISREG(mode));
-	dentry = start_creating(name, parent);
-
+	dentry = simplefs_create_file(&tracefs, &trace_fs_type,
+				      name, mode, parent, data, &inode);
 	if (IS_ERR(dentry))
 		return NULL;
 
-	inode = simple_new_inode(dentry->d_sb);
-	if (unlikely(!inode))
-		return failed_creating(dentry);
-
-	inode->i_mode = mode;
 	inode->i_fop = fops ? fops : &tracefs_file_operations;
-	inode->i_private = data;
-	d_instantiate(dentry, inode);
-	fsnotify_create(dentry->d_parent->d_inode, dentry);
-	return end_creating(dentry);
+	return simplefs_finish_dentry(dentry, inode);
 }
 
 static struct dentry *__create_dir(const char *name, struct dentry *parent,
 				   const struct inode_operations *ops)
 {
-	struct dentry *dentry = start_creating(name, parent);
+	struct dentry *dentry;
 	struct inode *inode;
 
+	dentry = simplefs_create_dir(&tracefs, &trace_fs_type,
+				     name, 0755, parent, &inode);
 	if (IS_ERR(dentry))
 		return NULL;
 
-	inode = simple_new_inode(dentry->d_sb);
-	if (unlikely(!inode))
-		return failed_creating(dentry);
-
-	inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
 	inode->i_op = ops;
-	inode->i_fop = &simple_dir_operations;
-
-	/* directory inodes start off with i_nlink == 2 (for "." entry) */
-	inc_nlink(inode);
-	d_instantiate(dentry, inode);
-	inc_nlink(dentry->d_parent->d_inode);
-	fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
-	return end_creating(dentry);
+	return simplefs_finish_dentry(dentry, inode);
 }
 
 /**
-- 
2.25.2