On Mon, Dec 04, 2023 at 03:46:15PM -0800, Daniel Rosenberg via Linux-f2fs-devel
wrote:
> Blocks are tracked by u32, so the max permitted filesize is
> U32_MAX * BLOCK_SIZE. Additionally, in order to support crypto data unit
> sizes of 4K with a 16K block size with IV_INO_LBLK_{32,63}, we must
{32,63} should be {32,64}
> + /*
> + * For compatibility with FSCRYPT_POLICY_IV_INO_LBLK_{64,32} with a
> + * 4K crypto data unit, we must restrict the max filesize to what can
> + * fit within U32_MAX data units.
FSCRYPT_POLICY_IV_INO_LBLK_{64,32} should be
FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{64,32}
> + *
> + * Since the blocksize must currently be equal to the page size,
> + * we can use a constant for that. Note if this is not the case
> + * in the future that inode is NULL while setting up the superblock.
I'm not sure what the last sentence is trying to say.
> + */
> +
> + result = min(result, ((loff_t) U32_MAX * 4096) >> F2FS_BLKSIZE_BITS);
Is it intentional that this is off by 1? If indices can be up to U32_MAX, then
the maximum size is U32_MAX + 1. It's not a bad idea to go with the lower size,
so that max_index + 1 does not overflow. But that's not what the explanation
says, so this seems to be accidental.
- Eric
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
