os: TestRootConsistencyStat/Lstat failures on XFS due to size of directories not being the same

[perrinjerome]

Go version

go version go1.24.10 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/srv/slapgrid/slappart82/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/srv/slapgrid/slappart82/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build682903046=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/srv/slapgrid/slappart82/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/srv/slapgrid/slappart82/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/srv/slapgrid/slappart82/srv/runner/shared/golang1.24/8b98c5a01f12c3408c83115065009684/.build/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/srv/slapgrid/slappart82/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/srv/slapgrid/slappart82/srv/runner/shared/golang1.24/8b98c5a01f12c3408c83115065009684/.build/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.10'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

run bash all.bash to compile golang 1.24.10 using an XFS filesystem for /tmp.

test failed with:

--- FAIL: TestRootConsistencyStat (0.02s)
    --- FAIL: TestRootConsistencyStat/dir_slash_dot (0.00s)
        root_test.go:841: with root:    res=name:"." size:26 mode:drwxr-xr-x isdir:true
        root_test.go:842:               err=<nil>
        root_test.go:843: without root: res=name:"." size:18 mode:drwxr-xr-x isdir:true
        root_test.go:844:               err=<nil>
        root_test.go:845: want consistent results, got mismatch
    --- FAIL: TestRootConsistencyStat/dot_slash (0.00s)
    --- FAIL: TestRootConsistencyStat/symlink_slash_dot (0.00s)
    --- FAIL: TestRootConsistencyLstat/dir_slash_dot (0.00s)
    --- FAIL: TestRootConsistencyLstat/dot_slash (0.00s)
    --- FAIL: TestRootConsistencyLstat/symlink_slash_dot (0.00s)

If I understand correctly, this test checks that two different directories have the same size, but on XFS the size of a directory depends on the inode number, see this minimal reproduction, the size is either 18 or 26:

$ mkdir /tmp/a /tmp/b ; touch /tmp/a/file /tmp/b/file ;  stat  /tmp/a/. /tmp/b/.  ; rm -rf /tmp/a /tmp/b
  File: /tmp/a/.
  Size: 18              Blocks: 0          IO Block: 4096   directory
Device: fe02h/65026d    Inode: 2206925354  Links: 2
Access: (0755/drwxr-xr-x)  Uid: (  915/slapuser82)   Gid: ( 1083/slapuser82)
Access: 2026-06-15 11:40:04.095537868 +0300
Modify: 2026-06-15 11:40:04.095537868 +0300
Change: 2026-06-15 11:40:04.095537868 +0300
 Birth: 2026-06-15 11:40:04.095537868 +0300
  File: /tmp/b/.
  Size: 26              Blocks: 0          IO Block: 4096   directory
Device: fe02h/65026d    Inode: 4373669975  Links: 2
Access: (0755/drwxr-xr-x)  Uid: (  915/slapuser82)   Gid: ( 1083/slapuser82)
Access: 2026-06-15 11:40:04.095537868 +0300
Modify: 2026-06-15 11:40:04.095537868 +0300
Change: 2026-06-15 11:40:04.095537868 +0300
 Birth: 2026-06-15 11:40:04.095537868 +0300

apparently the code is https://github.com/torvalds/linux/blob/36808d5e983985bbda87e01059cccc071fe3ec8d/fs/xfs/libxfs/xfs_da_format.h#L233-L237 but basically it seems that this test is making assumptions on the size of directories that are not true for all filesystems.

What did you see happen?

sometimes test fails when running all.bash

What did you expect to see?

test pass

[gabyhelp]

Related Issues

• cmd/link/internal/ld: fallocate_test.go:61: unexpected disk usage: got 2 blocks, want at least 2048 #75795 (closed)
• FAIL: os_test.TestLongSymlink on XFS #62 (closed)
• cmd/link/internal/ld: fallocate_test.go failed test #50042 (closed)
• os: tempDirWithUnixSocket uses MkdirTemp instead of t.TempDir causing tests to fail if they're on different filesystems #78063 (closed)

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[dmitshur]

Thanks for the report. Please note that Go 1.24 is no longer supported per https://go.dev/doc/devel/release#policy. Does this still happen with Go 1.26/1.25 or at tip?

CC @neild.

[perrinjerome]

Thank you and sorry for not realizing this was already a non supported version. I just tried with 1.26.4 and the same problem happened.