Re: [Qemu-devel] [PATCH v2] iscsi: Translate scsi sense into error code

[Fam Zheng <famz@redhat.com>]

On Wed, 11/04 21:12, Peter Lieven wrote:
> Am 04.11.2015 um 02:36 schrieb Fam Zheng:
> > Previously we return -EIO blindly when anything goes wrong. Add a helper
> > function to parse sense fields and try to make the return code more
> > meaningful.
> >
> > This also fixes the default werror configuration (enospc) when we're
> > using qcow2 on an iscsi lun. The old -EIO not being treated as out of
> > space error failed to trigger vm stop.
> >
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> >
> > ---
> > v2: Drop the qcow2 patch with ERANGE -> ENOSPC.
> >     Drop dead break after return.
> >     Return EIO for NO_SENSE.
> >     Translate error code for other I/O paths too.
> > ---
> >  block/iscsi.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++--------
> >  1 file changed, 55 insertions(+), 8 deletions(-)
> >
> > diff --git a/block/iscsi.c b/block/iscsi.c
> > index 9a628b7..b1bc0ef 100644
> > --- a/block/iscsi.c
> > +++ b/block/iscsi.c
> > @@ -84,6 +84,7 @@ typedef struct IscsiTask {
> >      IscsiLun *iscsilun;
> >      QEMUTimer retry_timer;
> >      bool force_next_flush;
> > +    int err_code;
> >  } IscsiTask;
> >  
> >  typedef struct IscsiAIOCB {
> > @@ -182,6 +183,51 @@ static inline unsigned exp_random(double mean)
> >  #define QEMU_SCSI_STATUS_TIMEOUT        SCSI_STATUS_TIMEOUT
> >  #endif
> >  
> > +static int iscsi_translate_sense(struct scsi_sense *sense)
> > +{
> > +    int ret;
> > +
> > +    switch (sense->key) {
> > +    case SCSI_SENSE_NOT_READY:
> > +        return -EBUSY;
> > +    case SCSI_SENSE_DATA_PROTECTION:
> > +        return -EACCES;
> > +    case SCSI_SENSE_COMMAND_ABORTED:
> > +        return -ECANCELED;
> > +    case SCSI_SENSE_ILLEGAL_REQUEST:
> > +        /* Parse ASCQ */
> > +        break;
> > +    default:
> > +        return -EIO;
> > +    }
> > +    switch (sense->ascq) {
> > +    case SCSI_SENSE_ASCQ_PARAMETER_LIST_LENGTH_ERROR:
> > +    case SCSI_SENSE_ASCQ_INVALID_OPERATION_CODE:
> > +    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_CDB:
> > +    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST:
> > +        ret = -EINVAL;
> > +        break;
> > +    case SCSI_SENSE_ASCQ_LBA_OUT_OF_RANGE:
> > +        ret = -ENOSPC;
> > +        break;
> > +    case SCSI_SENSE_ASCQ_LOGICAL_UNIT_NOT_SUPPORTED:
> > +        ret = -ENOTSUP;
> > +        break;
> > +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT:
> > +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_CLOSED:
> > +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_OPEN:
> > +        ret = -ENOMEDIUM;
> > +        break;
> > +    case SCSI_SENSE_ASCQ_WRITE_PROTECTED:
> > +        ret = -EACCES;
> > +        break;
> > +    default:
> > +        ret = -EIO;
> > +        break;
> > +    }
> > +    return ret;
> > +}
> > +
> >  static void
> >  iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
> >                          void *command_data, void *opaque)
> > @@ -226,6 +272,7 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
> >                  return;
> >              }
> >          }
> > +        iTask->err_code = iscsi_translate_sense(&task->sense);
> >          error_report("iSCSI Failure: %s", iscsi_get_error(iscsi));
> >      } else {
> >          iTask->iscsilun->force_next_flush |= iTask->force_next_flush;
> > @@ -455,7 +502,7 @@ retry:
> >      }
> >  
> >      if (iTask.status != SCSI_STATUS_GOOD) {
> > -        return -EIO;
> > +        return iTask.err_code;
> >      }
> >  
> >      iscsi_allocationmap_set(iscsilun, sector_num, nb_sectors);
> > @@ -536,14 +583,14 @@ retry:
> >  
> >      lbas = scsi_datain_unmarshall(iTask.task);
> >      if (lbas == NULL) {
> > -        ret = -EIO;
> > +        ret = iTask.err_code;
> >          goto out;
> >      }
> 
> An unmarschalling error will not set iTask.err_code. It is likely
> 0 here. Please leave it at -EIO.
> 
> >  
> >      lbasd = &lbas->descriptors[0];
> >  
> >      if (sector_qemu2lun(sector_num, iscsilun) != lbasd->lba) {
> > -        ret = -EIO;
> > +        ret = iTask.err_code;
> >          goto out;
> >      }
> 
> This is an internal sanity check, iTask.err_code will also be 0 here.

You're right in both cases, will fix. Thanks!

Fam