Linux 4.14 vfs_read/vfs_write fixes

[behlendorf]

Description

Run SPL PR openzfs/spl#667 through automated testing. No ZFS change. SPL changes are for some Linux 4.14 compatibility. Replaces #6861.

Motivation and Context

To fix SPL compatibility with torvalds/linux@bd8df82b (released in 4.14). Incorporates several rounds of review feedback.

Fixes openzfs/spl#656

How Has This Been Tested?

Manually built and tested against 4.14.0-0.rc8.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the ZFS on Linux code style requirements.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• All commit messages are properly formatted and contain Signed-off-by.
• Change has been approved by a ZFS on Linux member.

[codecov]

Codecov Report

Merging #6866 into master will decrease coverage by 1.44%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #6866      +/-   ##
==========================================
- Coverage   75.19%   73.75%   -1.45%     
==========================================
  Files         298      298              
  Lines       94503    94503              
==========================================
- Hits        71058    69697    -1361     
- Misses      23445    24806    +1361

Flag	Coverage Δ
#kernel	72.84% <0%> (-1.65%)	⬇️
#user	66.67% <0%> (-0.74%)	⬇️

Impacted Files	Coverage Δ
module/zfs/zfs_onexit.c	54.05% <0%> (-22.98%)	⬇️
lib/libzfs/libzfs_sendrecv.c	57.54% <0%> (-18.97%)	⬇️
cmd/zed/agents/zfs_agents.c	75.78% <0%> (-15.63%)	⬇️
module/zfs/dmu_send.c	59.76% <0%> (-15.39%)	⬇️
cmd/zstreamdump/zstreamdump.c	35.48% <0%> (-13.18%)	⬇️
lib/libnvpair/libnvpair.c	5.25% <0%> (-11.65%)	⬇️
module/zfs/dsl_prop.c	76.48% <0%> (-8.5%)	⬇️
module/zfs/dsl_destroy.c	85.84% <0%> (-8.22%)	⬇️
module/zfs/dmu_object.c	86.71% <0%> (-7%)	⬇️
module/zfs/zfs_ioctl.c	76.57% <0%> (-6.35%)	⬇️
... and 52 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 13589da...0ba6a2e. Read the comment docs.

[behlendorf]

Closing, spl change merged.