Patches look good.. Reviewed-by: Babu Moger <babu.moger@xxxxxxx> > -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Mike Snitzer > Sent: Thursday, December 16, 2010 1:57 PM > To: linux-scsi@xxxxxxxxxxxxxxx > Cc: Menny_Hamburger@xxxxxxxx; Itay_Dar@xxxxxxxx; Rob_Thomas@xxxxxxxx; dm- > devel@xxxxxxxxxx > Subject: [PATCH v3][SCSI] scsi_dh: propagate SCSI device deletion > > From: Menny Hamburger <Menny_Hamburger@xxxxxxxx> > > Currently, when scsi_dh_activate() returns with an error > (e.g. SCSI_DH_NOSYS) the activate_complete callback is not called and > the error is not propagated to DM mpath. > > When a SCSI device attached to a device handler is deleted, userland > processes currently performing I/O on the device will have their I/O > hang forever. > > - Set SCSI_DH_NOSYS error when the handler is in the process of being > deleted (e.g. the SCSI device is in a SDEV_CANCEL or SDEV_DEL state). > > - Set SCSI_DH_DEV_OFFLINED error when device is in SDEV_OFFLINE state. > > - Call the activate_complete callback function directly from > scsi_dh_activate if an error has been set (when either the scsi_dh > internal data has already been deleted or is in the process of being > deleted). > > The patch was tested in an iSCSI environment, RDAC H/W handler and > multipath. In the following reproduction process, dd will I/O hang > forever and the only way to release it will be to reboot the machine: > 1) Perform I/O on a multipath device: > dd if=/dev/dm-0 of=/dev/zero bs=8k count=1000000 & > 2) Delete all slave SCSI devices contained in the mpath device: > I) In an iSCSI environment, the easiest way to do this is by > stopping iSCSI: > /etc/init.d/iscsi stop > II) Another way to delete the devices is by applying the following > bash scriptlet: > dm_devs=$(ls /sys/block/ | grep dm- | xargs) > for dm_dev in $dm_devs; do > devices=$(ls /sys/block/$dm_dev/slaves) > for device in $devices; do > echo 1 > /sys/block/$device/device/delete > done > done > > NOTE: when DM mpath's fail_path uses blk_abort_queue this scsi_dh change > isn't strictly required. However, DM mpath's call to blk_abort_queue > will soon be reverted because it has proven to be unsafe due to a race > (between blk_abort_queue and scsi_request_fn) that can lead to list > corruption. Therefore we cannot rely on blk_abort_queue via fail_path, > but even if we could this scsi_dh change is still preferrable. > > Signed-off-by: Menny Hamburger <Menny_Hamburger@xxxxxxxx> > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > --- > drivers/scsi/device_handler/scsi_dh.c | 11 +++++++++-- > 1 files changed, 9 insertions(+), 2 deletions(-) > > v1 and v2 were posted/discussed on dm-devel > v3: just tweaked the patch header a bit > > diff --git a/drivers/scsi/device_handler/scsi_dh.c > b/drivers/scsi/device_handler/scsi_dh.c > index 6fae3d2..b0c56f6 100644 > --- a/drivers/scsi/device_handler/scsi_dh.c > +++ b/drivers/scsi/device_handler/scsi_dh.c > @@ -442,12 +442,19 @@ int scsi_dh_activate(struct request_queue *q, > activate_complete fn, void *data) > sdev = q->queuedata; > if (sdev && sdev->scsi_dh_data) > scsi_dh = sdev->scsi_dh_data->scsi_dh; > - if (!scsi_dh || !get_device(&sdev->sdev_gendev)) > + if (!scsi_dh || !get_device(&sdev->sdev_gendev) || > + sdev->sdev_state == SDEV_CANCEL || > + sdev->sdev_state == SDEV_DEL) > err = SCSI_DH_NOSYS; > + if (sdev->sdev_state == SDEV_OFFLINE) > + err = SCSI_DH_DEV_OFFLINED; > spin_unlock_irqrestore(q->queue_lock, flags); > > - if (err) > + if (err) { > + if (fn) > + fn(data, err); > return err; > + } > > if (scsi_dh->activate) > err = scsi_dh->activate(sdev, fn, data); > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
