From: Hannes Reinecke <hare@xxxxxxx> Instead of just passing 'EIO' for any I/O error we should be notifying the upper layers with more details about the cause of this error. Update the possible I/O errors to: - ENOLINK: Link failure between host and target - EIO: Retryable I/O error - EREMOTEIO: Non-retryable I/O error 'Retryable' in this context means that an I/O error _might_ be restricted to the I_T_L nexus (vulgo: path), so retrying on another nexus / path might succeed. 'Non-retryable' means target failure or reservation conflict. Signed-off-by: Hannes Reinecke <hare@xxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> --- drivers/scsi/scsi_error.c | 24 +++++++++++++++++------- drivers/scsi/scsi_lib.c | 24 ++++++++++++++++++++++-- include/scsi/scsi.h | 3 +++ 3 files changed, 42 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 824b8fc..48fdd85 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -223,7 +223,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost, * @scmd: Cmd to have sense checked. * * Return value: - * SUCCESS or FAILED or NEEDS_RETRY + * SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR * * Notes: * When a deferred error is detected the current command has @@ -326,17 +326,19 @@ static int scsi_check_sense(struct scsi_cmnd *scmd) */ return SUCCESS; - /* these three are not supported */ + /* these are not supported */ case COPY_ABORTED: case VOLUME_OVERFLOW: case MISCOMPARE: - return SUCCESS; + case BLANK_CHECK: + case DATA_PROTECT: + return TARGET_ERROR; case MEDIUM_ERROR: if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */ sshdr.asc == 0x13 || /* AMNF DATA FIELD */ sshdr.asc == 0x14) { /* RECORD NOT FOUND */ - return SUCCESS; + return TARGET_ERROR; } return NEEDS_RETRY; @@ -344,11 +346,9 @@ static int scsi_check_sense(struct scsi_cmnd *scmd) if (scmd->device->retry_hwerror) return ADD_TO_MLQUEUE; else - return SUCCESS; + return TARGET_ERROR; case ILLEGAL_REQUEST: - case BLANK_CHECK: - case DATA_PROTECT: default: return SUCCESS; } @@ -809,6 +809,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, case SUCCESS: case NEEDS_RETRY: case FAILED: + case TARGET_ERROR: break; case ADD_TO_MLQUEUE: rtn = NEEDS_RETRY; @@ -1502,6 +1503,14 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd) rtn = scsi_check_sense(scmd); if (rtn == NEEDS_RETRY) goto maybe_retry; + else if (rtn == TARGET_ERROR) { + /* + * Need to modify host byte to signal a + * permanent target failure + */ + scmd->result |= (DID_TARGET_FAILURE << 16); + rtn = SUCCESS; + } /* if rtn == FAILED, we have no sense information; * returning FAILED will wake the error handler thread * to collect the sense and redo the decide @@ -1519,6 +1528,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd) case RESERVATION_CONFLICT: sdev_printk(KERN_INFO, scmd->device, "reservation conflict\n"); + scmd->result |= (DID_TARGET_FAILURE << 16); return SUCCESS; /* causes immediate i/o error */ default: return FAILED; diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index eafeeda..4da6459 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -667,6 +667,26 @@ void scsi_release_buffers(struct scsi_cmnd *cmd) } EXPORT_SYMBOL(scsi_release_buffers); +static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result) +{ + int error = 0; + + switch(host_byte(result)) { + case DID_TRANSPORT_FAILFAST: + error = -ENOLINK; + break; + case DID_TARGET_FAILURE: + cmd->result |= (DID_OK << 16); + error = -EREMOTEIO; + break; + default: + error = -EIO; + break; + } + + return error; +} + /* * Function: scsi_io_completion() * @@ -737,7 +757,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) req->sense_len = len; } if (!sense_deferred) - error = -EIO; + error = __scsi_error_from_host_byte(cmd, result); } req->resid_len = scsi_get_resid(cmd); @@ -796,7 +816,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) return; - error = -EIO; + error = __scsi_error_from_host_byte(cmd, result); if (host_byte(result) == DID_RESET) { /* Third party bus reset or reset for error recovery diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index 216af85..73d27d9 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -405,6 +405,8 @@ static inline int scsi_is_wlun(unsigned int lun) * recover the link. Transport class will * retry or fail IO */ #define DID_TRANSPORT_FAILFAST 0x0f /* Transport class fastfailed the io */ +#define DID_TARGET_FAILURE 0x10 /* Permanent target failure, do not retry on + * other paths */ #define DRIVER_OK 0x00 /* Driver status */ /* @@ -434,6 +436,7 @@ static inline int scsi_is_wlun(unsigned int lun) #define TIMEOUT_ERROR 0x2007 #define SCSI_RETURN_NOT_HANDLED 0x2008 #define FAST_IO_FAIL 0x2009 +#define TARGET_ERROR 0x200A /* * Midlevel queue return values. -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html