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authorMenny Hamburger <Menny_Hamburger@Dell.com>2010-12-16 14:57:07 -0500
committerJames Bottomley <James.Bottomley@suse.de>2010-12-21 12:37:27 -0600
commitdb422318cbca55168cf965f655471dbf8be82433 (patch)
tree2d433a285c4ff23a2be684f5b8e88ed2415d7d5e /drivers/scsi/device_handler
parent35dd3039e09cd46ca3a8733ff1c817bf7b7b19ce (diff)
downloadop-kernel-dev-db422318cbca55168cf965f655471dbf8be82433.zip
op-kernel-dev-db422318cbca55168cf965f655471dbf8be82433.tar.gz
[SCSI] scsi_dh: propagate SCSI device deletion
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@Dell.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Babu Moger <babu.moger@lsi.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/device_handler')
-rw-r--r--drivers/scsi/device_handler/scsi_dh.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 6fae3d2..b837c5b 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);
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