Make scsi error recovery play nice with devices blocked by transport
RFC 1/1 Make scsi error recovery play nice with devices blocked by transport
Error recovery doesn't interact very well with fc targets which have been blocked by the fc transport. Error recovery continues to attempt to recover the target and ends up marking the fc target offline. Once offline, if the target returns before the remote port is removed, commands which could have been successfully reissued instead are completed with an error status due to the offline status of the target.
This patch makes a couple of hopefully minor tweaks to the error recovery logic to work better with targets which have been blocked by the transport.
First, if the target is blocked and error recovery gives up, don't put the device offline. Either the transport will delete the target thus disposing of any queued requests or it will unblock the target and requests will be reissued.
Second, if a device is blocked, queue up commands being flushed from the done queue for retry instead of completing them with an error.
Comments?
Thanks,
Mike Reed
===========================================================================linux/drivers/scsi/scsi_error.c
===========================================================================
drivers/scsi/scsi_error.c +11 -6
@@ -1125,10 +1125,14 @@struct scsi_cmnd *scmd, *next;list_for_each_entry_safe (scmd, next, work_q, eh_entry) { -sdev_printk (KERN_INFO , scmd->device, -"scsi: Device offlined - not" -" ready after error recovery\n" ); -scsi_device_set_state (scmd->device,SDEV_OFFLINE ); +/* if blocked, transport will provide final device disposition */ +if (!scsi_device_blocked (scmd->device)) { +sdev_printk (KERN_INFO , scmd->device, +"scsi: Device offlined - not" +" ready after error recovery\n" ); +scsi_device_set_state (scmd->device,SDEV_OFFLINE ); + } +if (scmd->eh_eflags &SCSI_EH_CANCEL_CMD ) {/* * FIXME: Handle lost cmds.
@@ -1455,9 +1459,10 @@list_for_each_entry_safe (scmd, next, done_q, eh_entry) {list_del_init (&scmd->eh_entry); -if (scsi_device_online (scmd->device) && +if (scsi_device_blocked (scmd->device) || + (scsi_device_online (scmd->device) && !blk_noretry_request (scmd->request) && - (++scmd->retries < scmd->allowed)) { + (++scmd->retries < scmd->allowed))) { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush" " retry cmd: %p\n", current->comm,
===========================================================================linux/include/scsi/scsi_device.h
===========================================================================
include/scsi/scsi_device.h +5 -0
@@ -275,6 +275,11 @@ int data_direction, void *buffer, unsigned bufflen, struct scsi_sense_hdr *, int timeout, int retries); +static inline int scsi_device_blocked (struct scsi_device *sdev) +{ +return sdev->sdev_state ==SDEV_BLOCK ; +} +static inline unsigned int sdev_channel (struct scsi_device *sdev) {return sdev->channel;