[Libguestfs] libguestfs "test-mdadm.sh" and php tests failing?

[Laszlo Ersek]

On 02/17/22 14:12, Richard W.M. Jones wrote:
> On Thu, Feb 17, 2022 at 01:41:04PM +0100, Laszlo Ersek wrote:
>> I've got a patch for the md-create chunk issue, and passed --disable-php
>> to ./configure. Now the "test-fuse" case is failing with:
>>
>> 01: checking initial files exist
>> 02: checking initial files contain expected content
>> 03: checking file modes and sizes of initial content
>> 04: checking unlink
>> libguestfs: error: lstatns: /new: No such file or directory
>> 05: checking symbolic link
>> libguestfs: error: lstatns: /symlink: No such file or directory
>> 06: checking readlink
>> 07: checking hard link
>> libguestfs: error: lstatns: /link: No such file or directory
>> nlink of 'hello.txt' was 1 (expected 2)
>> test_fuse() returned -1
>> /usr/sbin/fuser /tmp/testfusemUdOym
>> guestunmount /tmp/testfusemUdOym
>>
>> Should I disable FUSE as well?
> 
> I have these two skips:
> 
> export SKIP_TEST_FUSE_UMOUNT_RACE_SH=1
> export SKIP_TEST_GUESTMOUNT_FD=1
> 
> However I don't think the should affect this particular test, so there
> must be some other problem.
> 
> Using this might help to diagnose it:
> 
> LIBGUESTFS_DEBUG=1 LIBGUESTFS_TRACE=1 make check -C fuse

It seems to be related to caching. I couldn't narrow it down very well
because there seem to be two levels of caching, one from "standard
FUSE", another from "lib/fuse.c" ("we also implement a readdir cache").

Regardless, blocking the test program right after the fork(), with a
loop on a volatile int dummy, attaching separate gdb instances to both
child and parent, and unblocking both loops, I can successfully step
through the test case. The difference is apparently how much time passes
between the various link, stat, etc calls.

I've tried adding "GUESTFS_MOUNT_LOCAL_CACHETIMEOUT, 0" to
guestfs_mount_local(), but it made no difference.

We already have a caching-related "#if 0" in this test case; I think
it's more of the same.

Thanks
Laszlo