> On Jul 28, 2020, at 12:28 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > On Mon, Jul 27, 2020 at 12:11:19PM -0700, Ritika Srivastava wrote: >> Hence block layer issues write zeroes in blkdev_issue_zeroout() >> >> In response, the storage returns the following SCSI error >> Sense Key : Illegal Request [current] >> Add. Sense: Invalid command operation code >> >> Once this error is received, the write zero capability of the device is disabled and write_zeroes_max_bytes is set to 0. >> DM device queue limits are also set to 0 and device-mapper fails the path. >> To avoid this, if BLK_STS_NOTSUPP could be returned, then device-mapper would not fail the paths. >> >> Once the write zero capability has been disabled, blk-lib issues zeroes via __blkdev_issue_zero_pages(). >> >> Please let me know if I missed something. > > Oh, the stupid SCSI runtime detection case again. Can you please > document this in a comment? > > Also please switch blk_cloned_rq_check_limits to just return the > blk_status_t directly. Sure, I will make these changes and send updated version. Thanks, Ritika
