tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: I think I've found why Xen domUs can't mount some file-backed disk images! (vnd(4) hides labels!) (=?UTF-8?B?SmFyb23DrXIgRG9sZcSNZWs=?=) writes:

>Le dim. 11 avr. 2021 =C3=A0 17:51, Robert Elz <> a =C3=A9c=
>rit :
>>     Date:        Sun, 11 Apr 2021 14:25:40 -0000 (UTC)
>>     From: (Michael van Elst)
>>     Message-ID:  <s4v0t4$5c8$>
>>   | +       dg->dg_secperunit =3D vnd->sc_size / DEV_BSIZE;
>> While it shouldn't make any difference for any properly created image
>> file, make it be
>>                         (vnd->sc_size + DEV_BSIZE - 1) / DEV_BSIZE;
>> so that any trailing partial sector remains in the image.

>I don't think it's a good idea to include the sector which can't be written=
> to.

It cannot be read either (in the default strategy mode) and writing
to it in file mode would extend the file. Fortunately sc_size is
already compute as number of DEV_BSIZE blocks, truncated from the
byte length.

I also hear people lamenting that the notion of disk sectors was a mistake
and we should have never left the sea^Uthat disks should be byte-addressible
(but not bit-addressable!).

Home | Main Index | Thread Index | Old Index