fuse-overlayfs: try alternative whiteout on ENOTSUP

[giuseppe]

if mknod fails with ENOTSUP then use the .wh.FILE variant.

Closes: #17

Signed-off-by: Giuseppe Scrivano gscrivan@redhat.com

[rhatdan]

LGTM except tests are failing.

[giuseppe]

the CI needed an additional package, tests are fine now. @vbatts does this PR solve the issue you've seen?

[vbatts]

something is not right with this now. I haven't even made it to fully testing #17, but just on the cd /tmp/merged.

Since I happen to have a large enough $HOME folder and a $PS1 that looks for a .git folder, with this fix now cd /tmp/merged causes fuse-overlayfs to freeze when my $PS1 scans for git changes. I can't crtl+c, only killall -9 fuse-overlayfs and umount /tmp/merged to cleanup.

[vbatts]

(this freeze does not happen in 79c70fd)

[vbatts]

oh! but the freeze does happen in 1c72a1a. So it isn't this PR, but a bisect between #13, #14, and #15

[giuseppe]

I am still investigating, I've tried with some big git repositories I've under $HOME but I am still unable to reproduce the freeze.

The only patch that could introduce such issue seems to be b3898da

Does it work for you if you revert that commit?

Also, what do you see if you use --debug or attach gdb/strace to it? Where is it hanging?

[giuseppe]

I am merging this PR as it also solves a problem with the CI