[patch] MFI should set bio_resid on command failure

[Scott Long]

----- Original Message -----
> From: Sean Bruno <seanbru at yahoo-inc.com>
> To: Andrew Boyer <aboyer at averesystems.com>
> Cc: "freebsd-scsi at freebsd.org" <freebsd-scsi at freebsd.org>; scottl at freebsd.org; "ambrisko at FreeBSD.ORG" <ambrisko at freebsd.org>
> Sent: Tuesday, July 10, 2012 10:43 AM
> Subject: Re: [patch] MFI should set bio_resid on command failure
> 
> On Tue, 2012-07-10 at 09:37 -0700, Andrew Boyer wrote:
>>  On Jul 3, 2012, at 2:41 PM, Sean Bruno wrote:
>> 
>>  > On Tue, 2012-07-03 at 06:47 -0700, Andrew Boyer wrote:
>>  >> When an MFI command fails, the driver needs to set 
> bio->bio_resid so that the upper levels notice.  Otherwise we see commands 
> silently failing leading to data corruption.  This mirrors dadone().
>>  >> 
>>  >> -Andrew
>>  >> 
>>  >> Index: sys/dev/mfi/mfi_disk.c
>>  >> 
> ===================================================================
>>  >> --- sys/dev/mfi/mfi_disk.c    (revision 238071)
>>  >> +++ sys/dev/mfi/mfi_disk.c    (working copy)
>>  >> @@ -298,6 +298,7 @@
>>  >>     hdr = bio->bio_driver1;
>>  >> 
>>  >>     if (bio->bio_flags & BIO_ERROR) {
>>  >> +        bio->bio_resid = bio->bio_bcount;
>>  >>         if (bio->bio_error == 0)
>>  >>             bio->bio_error = EIO;
>>  >>         disk_err(bio, "hard error", -1, 1);
>>  >> 
>>  >> --------------------------------------------------
>>  >> Andrew Boyer    aboyer at averesystems.com
>>  >> 
>>  > 
>>  > This looks right to me.  It mirrors the behavior in 
> mfi_disk_strategy()
>>  > as well.
>>  > 
>>  > Sean
>>  > 
>> 
>>  Anyone interested in committing?  (And MFC'ing to stable/8…)
>> 
>>  -Andrew
>> 
>>  --------------------------------------------------
>>  Andrew Boyer    aboyer at averesystems.com
>> 
>> 
>> 
> 
> Let me hit dougA and scottl for validation.  Their wisdom here can
> validate my naivete.
> 


Yeah, b_resid needs to be set, and a lot of drivers get this wrong.

Scott