From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: [PATCHv6 1/8] scsi_error: count medium access timeout only once per EH run Date: Thu, 6 Apr 2017 15:36:29 +0200 Message-ID: <1491485796-44411-2-git-send-email-hare@suse.de> References: <1491485796-44411-1-git-send-email-hare@suse.de> Return-path: Received: from mx2.suse.de ([195.135.220.15]:38431 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934751AbdDFNgr (ORCPT ); Thu, 6 Apr 2017 09:36:47 -0400 In-Reply-To: <1491485796-44411-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: James Bottomley , Christoph Hellwig , Bart van Assche , linux-scsi@vger.kernel.org, Hannes Reinecke , Ewan Milne , Lawrence Obermann , Benjamin Block , Steffen Maier , Hannes Reinecke The current medium access timeout counter will be increased for each command, so if there are enough failed commands we'll hit the medium access timeout for even a single device failure and the following kernel message is displayed: sd H:C:T:L: [sdXY] Medium access timeout failure. Offlining disk! Fix this by making the timeout per EH run, ie the counter will only be increased once per device and EH run. Fixes: 18a4d0a ("[SCSI] Handle disk devices which can not process medium access commands") Cc: Ewan Milne Cc: Lawrence Obermann Cc: Benjamin Block Cc: Steffen Maier Signed-off-by: Hannes Reinecke Reviewed-by: Christoph Hellwig --- drivers/scsi/scsi_error.c | 18 ++++++++++++++++++ drivers/scsi/sd.c | 27 ++++++++++++++++++++++++++- drivers/scsi/sd.h | 1 + include/scsi/scsi_driver.h | 1 + 4 files changed, 46 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index f2cafae..370f6c0 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -221,6 +221,23 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost) } /** + * scsi_eh_reset - call into ->eh_action to reset internal counters + * @scmd: scmd to run eh on. + * + * The scsi driver might be carrying internal state about the + * devices, so we need to call into the driver to reset the + * internal state once the error handler is started. + */ +static void scsi_eh_reset(struct scsi_cmnd *scmd) +{ + if (!blk_rq_is_passthrough(scmd->request)) { + struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd); + if (sdrv->eh_reset) + sdrv->eh_reset(scmd); + } +} + +/** * scsi_eh_scmd_add - add scsi cmd to error handling. * @scmd: scmd to run eh on. * @eh_flag: optional SCSI_EH flag. @@ -249,6 +266,7 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag) if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) eh_flag &= ~SCSI_EH_CANCEL_CMD; scmd->eh_eflags |= eh_flag; + scsi_eh_reset(scmd); list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); shost->host_failed++; scsi_eh_wakeup(shost); diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index d277e86..bd2a38e 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -115,6 +115,7 @@ static int sd_init_command(struct scsi_cmnd *SCpnt); static void sd_uninit_command(struct scsi_cmnd *SCpnt); static int sd_done(struct scsi_cmnd *); +static void sd_eh_reset(struct scsi_cmnd *); static int sd_eh_action(struct scsi_cmnd *, int); static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer); static void scsi_disk_release(struct device *cdev); @@ -532,6 +533,7 @@ static void sd_set_flush_flag(struct scsi_disk *sdkp) .uninit_command = sd_uninit_command, .done = sd_done, .eh_action = sd_eh_action, + .eh_reset = sd_eh_reset, }; /* @@ -1686,6 +1688,26 @@ static int sd_pr_clear(struct block_device *bdev, u64 key) }; /** + * sd_eh_reset - reset error handling callback + * @scmd: sd-issued command that has failed + * + * This function is called by the SCSI midlayer before starting + * SCSI EH. When counting medium access failures we have to be + * careful to register it only only once per device and SCSI EH run; + * there might be several timed out commands which will cause the + * 'max_medium_access_timeouts' counter to trigger after the first + * SCSI EH run already and set the device to offline. + * So this function resets the internal counter before starting SCSI EH. + **/ +static void sd_eh_reset(struct scsi_cmnd *scmd) +{ + struct scsi_disk *sdkp = scsi_disk(scmd->request->rq_disk); + + /* New SCSI EH run, reset gate variable */ + sdkp->ignore_medium_access_errors = false; +} + +/** * sd_eh_action - error handling callback * @scmd: sd-issued command that has failed * @eh_disp: The recovery disposition suggested by the midlayer @@ -1714,7 +1736,10 @@ static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp) * process of recovering or has it suffered an internal failure * that prevents access to the storage medium. */ - sdkp->medium_access_timed_out++; + if (!sdkp->ignore_medium_access_errors) { + sdkp->medium_access_timed_out++; + sdkp->ignore_medium_access_errors = true; + } /* * If the device keeps failing read/write commands but TEST UNIT diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h index 4dac35e..0cf9680 100644 --- a/drivers/scsi/sd.h +++ b/drivers/scsi/sd.h @@ -106,6 +106,7 @@ struct scsi_disk { unsigned rc_basis: 2; unsigned zoned: 2; unsigned urswrz : 1; + unsigned ignore_medium_access_errors : 1; }; #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev) diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h index 891a658..a5534cc 100644 --- a/include/scsi/scsi_driver.h +++ b/include/scsi/scsi_driver.h @@ -16,6 +16,7 @@ struct scsi_driver { void (*uninit_command)(struct scsi_cmnd *); int (*done)(struct scsi_cmnd *); int (*eh_action)(struct scsi_cmnd *, int); + void (*eh_reset)(struct scsi_cmnd *); }; #define to_scsi_driver(drv) \ container_of((drv), struct scsi_driver, gendrv) -- 1.8.5.6