[PATCH v2 0/3] block: scsi: introduce and use BLK_STS_OFFLINE

[Song Liu <song@kernel.org>]

Changes v1 => v2:
1. Add patch 2/3 to change user visible return value to -ENODEV. (Hannes)
2. In the commit log, explain the reason to keep EIO in 1/3.

We have a use case where HDDs are regularly power on/off to perserve power.
When a drive is being removed, we often see errors like

   [  172.803279] I/O error, dev sda, sector 3137184

These messages are confusing for automations that grep dmesg, as they look
very similar to real HDD error.

Solve this issue with a new block state BLK_STS_OFFLINE. After the change,
the error message looks like

   [  172.803279] device offline error, dev sda, sector 3137184

so that the automations won't confuse them with real I/O error.

Song Liu (3):
  block: introduce BLK_STS_OFFLINE
  block: return -ENODEV for BLK_STS_OFFLINE
  scsi: use BLK_STS_OFFLINE for not fully online devices

 block/blk-core.c          | 1 +
 drivers/scsi/scsi_lib.c   | 2 +-
 include/linux/blk_types.h | 7 +++++++
 3 files changed, 9 insertions(+), 1 deletion(-)

--
2.30.2