MFC r332458:

MFC r332458:
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  r332458 | ken | 2018-04-12 15:21:18 -0600 (Thu, 12 Apr 2018) | 34 lines

  Handle Programmable Early Warning for control commands in sa(4).

  When the tape position is inside the Early Warning area, the tape
  drive will return a sense key of NO SENSE, and an ASC/ASCQ of
  0x00,0x02, which means: End-of-partition/medium detected".  If
  this was in response to a control command like WRITE FILEMARKS,
  we correctly translate this as informational status and return
  0 from saerror().

  Programmable Early Warning should be handled the same way, but
  we weren't handling it that way.  As a result, if a PEW status
  (sense key of NO SENSE, ASC/ASCQ of 0x00,0x07, "Programmable early
  warning detected") came back in response to a WRITE FILEMARKS,
  we returned an error.

  The impact of this was that if an application was writing to a
  sa(4) device, and a PEW area was set (in the Device Configuration
  Extension subpage -- mode page 0x10, subpage 1), and a filemark
  needed to be written on close, we could wind up returning an error
  to the user on close because of a "failure" to write the filemarks.

  It actually isn't a failure, but rather just a status report from
  the drive, and shouldn't be treated as a failure.

  sys/cam/scsi/scsi_sa.c:
  	For control commands in saerror(), treat asc/ascq 0x00,0x07
  	the same as 0x00,{0-5} -- not an error.  Return 0, since
  	the command actually did succeed.

  Reported by:	Dr. Andreas Haakh <andreas@haakh.de>
  Tested by:	Dr. Andreas Haakh <andreas@haakh.de>
  Sponsored by:	Spectra Logic
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git-svn-id: svn://svn.freebsd.org/base/stable/10@332933 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f