svn commit: r216230 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Ivan Voras]

On 6 December 2010 20:22, Pawel Jakub Dawidek <pjd at freebsd.org> wrote:
> On Mon, Dec 06, 2010 at 07:44:53PM +0100, Pawel Jakub Dawidek wrote:
>> On Mon, Dec 06, 2010 at 12:18:03PM +0000, Ivan Voras wrote:
>> > Author: ivoras
>> > Date: Mon Dec  6 12:18:02 2010
>> > New Revision: 216230
>> > URL: http://svn.freebsd.org/changeset/base/216230
>> >
>> > Log:
>> >   Use GEOM stripesize field when calculating ashift. This will enable correct
>> >   alignment on drives with large sector sizes (e.g. 4 KiB) but the
>> >   implementation might need to be revisited if devices with large stripesizes
>> >   appear (e.g. if RAID controllers or flash drives start using the field),
>> >   probably by introducing a physsectorsize field in GEOM providers.
>>
>> Please back this out as soon as possible!
>>
>> >   Discussed with: mav, mostly silence on freebsd-geom@ and freebsd-fs@
>>
>> Guess why it wasn't picked up by anyone?
>
> In other words... Stop hack around. This is so irritating.
>
> If disk lies about its sector size, add quirks at the layer where disk
> is discovered. Don't hack ZFS, UFS, any other file system and GEOM
> classes, because its easiest for you. It would be best if you could just
> leave it to mav@ who knows this area and knows what he is doing. Those
> drive-by hacks of yours are really doing more evil than good.

I regard your personal opinion on this topic in little regard, as you
have too much of it.

Please persuade me on technical grounds why ashift, a property
intended for address alignment, should not be set in this way. If your
answer is "I don't know but you are still wrong because I say so" I
will respect it and back it out but only until I/we discuss the
question with upstream ZFS developers.

>From my POW, this is similar to changing UFS default fragment size to
match stripesize, which is a patch I also intend to commit (after a
review by mckusick, or course).