Re: [PATCH V2] block: correctly fallback for zeroout

Martin K. Petersen
2016-06-11T01:50:24Z

>>>>> "Shaohua" == Shaohua Li <shli@fb.com> writes:

Shaohua,

>> What does the extra io_err buy us? Just have this function return an
>> error. And then in blkdev_issue_discard if you get -EOPNOTSUPP you
>> special case it there.

Shaohua> The __blkdev_issue_discard returns -EOPNOTSUPP if disk doesn't
Shaohua> support discard. in that case, blkdev_issue_discard doesn't
Shaohua> return 0. blkdev_issue_discard only returns 0 if IO error is
Shaohua> -EOPNOTSUPP.

Oh, I see. The sanity checks are now in __blkdev_issue_discard() so
there is no way to distinguish between -EOPNOTSUPP and the other
-EOPNOTSUPP. *sigh*

I am OK with your patch as a stable fix but this really needs to be
fixed up properly.

--
Martin K. Petersen Oracle Linux Engineering