split up btrfs_ioctl

Add a helper per ioctl function to make the code more readable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

@@ -1957,32 +1957,27 @@ int btrfs_defrag_file(struct file *file) {
 	return 0;
 }
 
-long btrfs_ioctl(struct file *file, unsigned int
-		cmd, unsigned long arg)
+static int btrfs_ioctl_snap_create(struct btrfs_root *root, void __user *arg)
 {
-	struct inode *inode = file->f_path.dentry->d_inode;
-	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_ioctl_vol_args vol_args;
-	int ret = 0;
 	struct btrfs_dir_item *di;
-	int namelen;
 	struct btrfs_path *path;
+	int namelen;
 	u64 root_dirid;
 
-	switch (cmd) {
-	case BTRFS_IOC_SNAP_CREATE:
-		if (copy_from_user(&vol_args,
-				   (struct btrfs_ioctl_vol_args __user *)arg,
-				   sizeof(vol_args)))
+	if (copy_from_user(&vol_args, arg, sizeof(vol_args)))
 		return -EFAULT;
+	
 	namelen = strlen(vol_args.name);
 	if (namelen > BTRFS_VOL_NAME_MAX)
 		return -EINVAL;
 	if (strchr(vol_args.name, '/'))
 		return -EINVAL;
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
+
 	root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 	mutex_lock(&root->fs_info->fs_mutex);
 	di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
@@ -1996,26 +1991,43 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return PTR_ERR(di);
 
 	if (root == root->fs_info->tree_root)
-			ret = create_subvol(root, vol_args.name, namelen);
-		else
-			ret = create_snapshot(root, vol_args.name, namelen);
-		break;
+		return create_subvol(root, vol_args.name, namelen);
+	return create_snapshot(root, vol_args.name, namelen);
+}
 
-	case BTRFS_IOC_DEFRAG:
-		if (S_ISDIR(inode->i_mode)) {
+static int btrfs_ioctl_defrag(struct file *file)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
+
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFDIR:
 		mutex_lock(&root->fs_info->fs_mutex);
 		btrfs_defrag_root(root, 0);
 		btrfs_defrag_root(root->fs_info->extent_root, 0);
 		mutex_unlock(&root->fs_info->fs_mutex);
-		} else if (S_ISREG(inode->i_mode)) {
+		break;
+	case S_IFREG:
 		btrfs_defrag_file(file);
-		}
-		ret = 0;
 		break;
-	default:
-		return -ENOTTY;
 	}
-	return ret;
+
+	return 0;
+}
+
+long btrfs_ioctl(struct file *file, unsigned int
+		cmd, unsigned long arg)
+{
+	struct btrfs_root *root = BTRFS_I(file->f_path.dentry->d_inode)->root;
+
+	switch (cmd) {
+	case BTRFS_IOC_SNAP_CREATE:
+		return btrfs_ioctl_snap_create(root, (void __user *)arg);
+	case BTRFS_IOC_DEFRAG:
+		return btrfs_ioctl_defrag(file);
+	}
+
+	return -ENOTTY;
 }
 
 /*