On 4/25/22 8:43 AM, Karel Zak wrote:
>
> Thanks Andrey,
>
> the code looks good.
>
> On Thu, Apr 21, 2022 at 03:09:44PM +0200, Andrey Albershteyn wrote:
>> I had a look into other fs, like ext4 and btrfs, to implement FSSIZE
>> for them, but I think I don't have enough expertize to do that as
>> they have not so trivial metadata overhead calculation :)
>
> But it would be nice to have ext4 and btrfs too. Maybe Eric can help
> you :-)
>
> Karel
For ext4 something like e2fsprogs does is probably ok:
static __u64 e2p_free_blocks_count(struct ext2_super_block *super)
{
return super->s_free_blocks_count |
(ext2fs_has_feature_64bit(super) ?
(__u64) super->s_free_blocks_hi << 32 : 0);
}
though I wonder if a little documentation on the intent of the flag is
in order; ext4 can return "df" in different ways (see the minixdf and
bsddf mount options.)
I think best effort seems fine here, and reporting the same number
as the ext4 utilities do should be fine.
As for btrfs - I'm really not sure what this should return on a
multi-device filesystem?
-Eric
