ext4: switch EXT4_IOC_RESIZE_FS to mnt_want_write_file()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ext4/ioctl.c

@@ -390,7 +390,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (err)
 			return err;
 
-		err = mnt_want_write(filp->f_path.mnt);
+		err = mnt_want_write_file(filp);
 		if (err)
 			goto resizefs_out;
 
@@ -402,7 +402,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		if (err == 0)
 			err = err2;
-		mnt_drop_write(filp->f_path.mnt);
+		mnt_drop_write_file(filp);
 resizefs_out:
 		ext4_resize_end(sb);
 		return err;