On Fri, Apr 16, 2021 at 05:52:41PM +0200, David Sterba wrote:
> On Wed, Apr 14, 2021 at 10:33:38AM +0900, Naohiro Aota wrote:
> > It also supports temporary magic ("!BHRfS_M") in zone #0. The mkfs.btrfs
> > first writes the temporary superblock to the zone during the mkfs process.
> > It will survive there until the zones are filled up and reset. So, we also
> > need to detect this temporary magic.
>
> > + /*
> > + * For zoned btrfs, we also need to detect a temporary superblock
> > + * at zone #0. Mkfs.btrfs creates it in the initialize process.
> > + * It persits until both zones are filled up then reset.
> > + */
> > + { .magic = "!BHRfS_M", .len = 8, .sboff = 0x40,
> > + .is_zoned = 1, .zonenum = 0, .kboff_inzone = 0 },
>
> Should we rather reset the zone twice so the initial superblock does not
> have the temporary signature?
OK, sure. I'll modify the mkfs.btrfs to reset the superblock log zone
before writing out final superblock.
> For the primary superblock at offset 64K and as a fallback the signature
> should be valid for detection purposes (ie. not necessarily to get the
> latest superblock).
