os: fsync on AIX on read-only files fails, should instead use fsync_range

[aklyachkin]

What version of Go are you using (go version)?

$ go version
go version go1.14.2 aix/ppc64

Does this issue reproduce with the latest release?

This is the latest release available for AIX

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="ppc64"
GOBIN=""
GOCACHE="/.cache/go-build"
GOENV="/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="ppc64"
GOHOSTOS="aix"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="aix"
GOPATH="/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/opt/freeware/lib/golang"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/freeware/lib/golang/pkg/tool/aix_ppc64"
GCCGO="gccgo"
GOPPC64="power8"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -maix64 -pthread -mcmodel=large -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build220147562=/tmp/go-build -gno-record-gcc-switches"

What did you do?

https://play.golang.org/p/PwSeWwxFj5B

# touch /tmp/1
# go run a.go
os.Sync(): sync /tmp/1: bad file number
Op: sync, Path: /tmp/1, Err: bad file number

What did you expect to see?

nothing ;-)

What did you see instead?

# touch /tmp/1
# go run a.go
os.Sync(): sync /tmp/1: bad file number
Op: sync, Path: /tmp/1, Err: bad file number

See the comment of Clément Chigot here - https://community.ibm.com/community/user/power/communities/community-home/digestviewer/viewthread?GroupId=6211&MessageKey=e0af00d7-1005-4acf-99b7-e0787e4cb463&CommunityKey=10c1d831-47ee-4d92-a138-b03f7896f7c9&tab=digestviewer&ReturnUrl=%2fcommunity%2fuser%2fpower%2fcommunities%2fcommunity-home%2fdigestviewer%3fcommunitykey%3d10c1d831-47ee-4d92-a138-b03f7896f7c9%26tab%3ddigestviewer

With os.O_RDWR instead of os.RDONLY it works.

[Helflym]

As I said in IBM forum, using fsync_range instead of fsync should work. I'm trying the patch right now and will submit it after that.

[gopherbot]

Change https://golang.org/cl/254657 mentions this issue: syscall: fix fsync for read-only files on aix