On 7/31/23 08:09, Christoph Hellwig wrote:
On Tue, Jul 25, 2023 at 09:00:59PM +0800, chengming.zhou@xxxxxxxxx wrote:
From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
The cmd_flags in blk_kick_flush() should inherit the original request's
cmd_flags, but the current code looks buggy to me:
Should it? I know the code is kinda trying to do it, but does it really
make sense? Adding Hannes who originally added this inheritance and
discussing the details below:
Yeah, it does.
The flush machinery is sending flushes before and/or after the original
request (preflush/postflush). For blocked transports (ie during FC RSCN
handling) the transport will error out commands depending on the
FAILFAST setting. If FAILFAST is set the SCSI layer gets an
STS_TRANSPORT error (causing the I/O to be retried), but STS_ERROR if
not set (causing I/O to failed).
So if the FAILFAST setting is _not_ aligned between flush_rq and the
original we'll get an error on the flush rq and a retry on the original
rq, causing the entire command to fail.
I guess we need to align them.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman
