[Libvir] PATCH: 12/16: logical volume backend
Jim Meyering
jim at meyering.net
Tue Feb 19 15:13:32 UTC 2008
"Daniel P. Berrange" <berrange at redhat.com> wrote:
...
>> > + for (i = 0 ; i < pool->def->source.ndevice ; i++) {
>> > + int fd;
>> > + char zeros[512];
>> > + memset(zeros, 0, sizeof(zeros));
...
>> is it really 512 or the block size on the device used ? But 512 is
>> probably sufficient for LVM to consider it cleared, just wondering ...
>
> The 'pvcreate' man page explicitly says the first sector
>
> <quote>
> For whole disk devices only the partition table must be erased,
> which will effectively destroy all data on that disk. This can
> be done by zeroing the first sector with:
>
> dd if=/dev/zero of=PhysicalVolume bs=512 count=1
> </quote>
>
> So 512 is fine for MSDOS partition tables at least.
How about giving the constant a name?
That'd make it more readable.
#define SECTOR_SIZE 512
--
Jim, who has spent far too much time dealing with hard-coded
literal array sizes like that in parted, when I made
parts of it work with larger-than-512-byte sectors.
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