Hey, On Sat, Jun 15, 2024 at 12:03:47AM +0800, Li Feng wrote: > There is a scenario where a large number of discard commands > are issued when the iscsi initiator connects to the target > and then performs a session rescan operation. Is this with just one specific target implementation? This sounds like a broken/buggy target, or is there a reason why this happens in general? And broken target sounds like device quirk, rather than impacting every possible target. > There is a time > window, most of the commands are in UNMAP mode, and some > discard commands become WRITE SAME with UNMAP. > > The discard mode has been negotiated during the SCSI probe. If > the mode is temporarily changed from UNMAP to WRITE SAME with > UNMAP, IO ERROR may occur because the target may not implement > WRITE SAME with UNMAP. Keep the discard mode stable to fix this > issue. > > Signed-off-by: Li Feng <fengli@xxxxxxxxxx> > --- > drivers/scsi/sd.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index f6c822c9cbd2..0165dc70a99b 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -2598,7 +2598,12 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, > if (buffer[14] & 0x40) /* LBPRZ */ > sdkp->lbprz = 1; > > - sd_config_discard(sdkp, SD_LBP_WS16); > + /* > + * When the discard mode has been set to UNMAP, it should not be set to > + * WRITE SAME with UNMAP. > + */ > + if (!sdkp->max_unmap_blocks) > + sd_config_discard(sdkp, SD_LBP_WS16); > } > > sdkp->capacity = lba + 1; -- Best Regards, Benjamin Block / Linux on IBM Z Kernel Development IBM Deutschland Research & Development GmbH / https://www.ibm.com/privacy Vors. Aufs.-R.: Wolfgang Wendt / Gesch?ftsf?hrung: David Faller Sitz der Ges.: B?blingen / Registergericht: AmtsG Stuttgart, HRB 243294
