Re: [PATCH 3/6] fs-verity: add FS_IOC_READ_VERITY_METADATA ioctl

On Sun, Feb 07, 2021 at 03:46:43PM +0800, Chao Yu wrote:

Hi Eric,

On 2021/1/16 2:18, Eric Biggers wrote:

quoted

+static int f2fs_ioc_read_verity_metadata(struct file *filp, unsigned long arg)
+{
+	if (!f2fs_sb_has_verity(F2FS_I_SB(file_inode(filp))))
+		return -EOPNOTSUPP;

One case is after we update kernel image, f2fs module may no longer support
compress algorithm which current file was compressed with, to avoid triggering
IO with empty compress engine (struct f2fs_compress_ops pointer):

It needs to add f2fs_is_compress_backend_ready() check condition here?

Thanks,

quoted

+
+	return fsverity_ioctl_read_metadata(filp, (const void __user *)arg);
+}

In that case it wouldn't have been possible to open the file, because
f2fs_file_open() checks for it.  So it's not necessary to repeat the same check
in every operation on the file descriptor.

- Eric