[PATCH v2 0/4] Improve fio max open zones handling

[Niklas Cassel <Niklas.Cassel@wdc.com>]

From: Niklas Cassel <niklas.cassel@wdc.com>

Improve max open zones handling by introducing a new IO engine operation,
which can be implemented by ioengines.

Also provide a default implementation for Linux, which parses sysfs for
the max open zones value.

Update libzbc ioengine to utilize the new callback.

Having this callback has the two following advantages:

1) If the user forgets to specify a --max_open_zones value, we will
automatically use the maximum the drive supports.
(Instead of getting errors because fio tries to open too many zones.)

2) If the user specifies a --max_open_zones value that is too big,
we will return an error and fio will exit with a proper error message.
(Instead of getting errors because fio tries to open too many zones.)


Changes since v1:
-Fixed all review comments from Damien, except the unconditional logging,
I still think that a debug print is sufficient.
-Picked up Reviewed-by tag by Damien on patch 4/4.

Niklas Cassel (4):
  zbd: only put an upper limit on max open zones once
  oslib/linux-blkzoned: move sysfs reading into its own function
  ioengines: add get_max_open_zones zoned block device operation
  engines/libzbc: add support for the get_max_open_zones io op

 engines/libzbc.c            | 21 +++++++++
 engines/skeleton_external.c | 13 ++++++
 ioengines.h                 |  4 +-
 oslib/blkzoned.h            |  7 +++
 oslib/linux-blkzoned.c      | 83 ++++++++++++++++++++++++---------
 zbd.c                       | 91 ++++++++++++++++++++++++++++++++++---
 6 files changed, 190 insertions(+), 29 deletions(-)

-- 
2.25.1