Re: [GIT PULL v5.1] libfuse: run fuse servers as a contained service

["Darrick J. Wong" <djwong@kernel.org>]

On Sat, May 02, 2026 at 06:58:30PM +0200, Bernd Schubert wrote:
> 
> 
> On 5/2/26 18:30, Darrick J. Wong wrote:
> > On Sat, May 02, 2026 at 05:59:06PM +0200, Bernd Schubert wrote:
> >>
> >>
> >> On 5/1/26 00:49, Darrick J. Wong wrote:
> >>> On Thu, Apr 30, 2026 at 11:34:06PM +0200, Bernd Schubert wrote:
> >>>> Hi Darrick,
> >>>>
> >>>> On 4/30/26 23:18, Darrick J. Wong wrote:
> >>>>> Hi Bernd,
> >>>>>
> >>>>> Please pull this branch with changes for libfuse.
> >>>>>
> >>>>> As usual, I did a test-merge with the main upstream branch as of a few
> >>>>> minutes ago, and didn't see any conflicts.  Please let me know if you
> >>>>> encounter any problems.
> >>>>
> >>>> pushed to my github branch. BSD build fails with
> >>>>
> >>>> 2026-04-30T21:25:16.3874802Z FAILED: [code=1] lib/libfuse3.so.3.19.0 
> >>>> 2026-04-30T21:25:16.3906762Z cc  -o lib/libfuse3.so.3.19.0 lib/libfuse3.so.3.19.0.p/fuse.c.o lib/libfuse3.so.3.19.0.p/fuse_loop.c.o lib/libfuse3.so.3.19.0.p/fuse_loop_mt.c.o lib/libfuse3.so.3.19.0.p/fuse_lowlevel.c.o lib/libfuse3.so.3.19.0.p/fuse_opt.c.o lib/libfuse3.so.3.19.0.p/fuse_signals.c.o lib/libfuse3.so.3.19.0.p/buffer.c.o lib/libfuse3.so.3.19.0.p/cuse_lowlevel.c.o lib/libfuse3.so.3.19.0.p/helper.c.o lib/libfuse3.so.3.19.0.p/modules_subdir.c.o lib/libfuse3.so.3.19.0.p/mount_util.c.o lib/libfuse3.so.3.19.0.p/fuse_log.c.o lib/libfuse3.so.3.19.0.p/compat.c.o lib/libfuse3.so.3.19.0.p/util.c.o lib/libfuse3.so.3.19.0.p/mount_bsd.c.o lib/libfuse3.so.3.19.0.p/fuse_service_stub.c.o lib/libfuse3.so.3.19.0.p/modules_iconv.c.o -Wl,--as-needed -Wl,--no-undefined -shared -fPIC -Wl,-soname,libfuse3.so.4 -Wl,--version-script,/home/runner/work/libfuse/libfuse/lib/fuse_versionscript -pthread -Wl,--start-group -ldl -lrt -Wl,--end-group
> >>>> 2026-04-30T21:25:16.3939590Z ld: error: version script assignment of 'FUSE_3.19' to symbol 'fuse_service_can_allow_other' failed: symbol not defined
> >>>
> >>> Aha, that function got left out of the stub. :(
> >>>
> >>> Annoyingly, on Linux the build succeeds despite the missing symbol
> >>> when I tweak meson so that it doesn't build the service stuff.  I would
> >>> have thought that --no-undefined would have done that, but alas.
> >>>
> >>> Sorry about that too.  The following patch fixes it.
> >>>
> >>> diff --git i/lib/fuse_service_stub.c w/lib/fuse_service_stub.c
> >>> index d34df3891a6e31..231b98423df628 100644
> >>> --- i/lib/fuse_service_stub.c
> >>> +++ w/lib/fuse_service_stub.c
> >>> @@ -49,12 +49,17 @@ int fuse_service_send_goodbye(struct fuse_service *sf, int error)
> >>>  int fuse_service_accept(struct fuse_service **sfp)
> >>>  {
> >>>  	*sfp = NULL;
> >>>  	return 0;
> >>>  }
> >>>  
> >>> +bool fuse_service_can_allow_other(struct fuse_service *sf)
> >>> +{
> >>> +	return false;
> >>> +}
> >>> +
> >>>  int fuse_service_append_args(struct fuse_service *sf,
> >>>  			     struct fuse_args *existing_args)
> >>>  {
> >>>  	return -EOPNOTSUPP;
> >>>  }
> >>>  
> >>>
> >>>> 2026-04-30T21:25:16.3951874Z cc: error: linker command failed with exit code 1 (use -v to see invocation)
> >>>> 2026-04-30T21:25:16.4291582Z [44/82] cc -Itest/test_teardown_watchdog.p -Itest -I../test -Iinclude -I../include -Ilib -I../lib -I. -I.. -fdiagnostics-color=always -
> >>>>
> >>>>
> >>>> checkpatch, CodeChecker-cppcheck, CodeChecker-gcc also all fail. This CodeQL
> >>>
> >>> Not sure why checkpatch fails, this is what I got (Debian 13):
> >>>
> >>> $ git diff origin/master.. | ./checkpatch.pl --max-line-length=100 --no-tree --ignore MAINTAINERS,SPDX_LICENSE_TAG,COMMIT_MESSAGE,FILE_PATH_CHANGES,EMAIL_SUBJECT,AVOID_EXTERNS,GIT_COMMIT_ID,ENOSYS_SYSCALL,ENOSYS,FROM_SIGN_OFF_MISMATCH,QUOTED_COMMIT_ID,,PREFER_ATTRIBUTE_ALWAYS_UNUSED,PREFER_DEFINED_ATTRIBUTE_MACRO,STRCPY,STRNCPY -
> >>> No typos will be found - file '/storage/home/djwong/cdev/work/libfuse/spelling.txt': No such file or directory
> >>> No structs that should be const will be found - file '/storage/home/djwong/cdev/work/libfuse/const_structs.checkpatch': No such file or directory
> >>> total: 0 errors, 0 warnings, 3908 lines checked
> >>>
> >>> Your patch has no obvious style problems and is ready for submission.
> >>>
> >>> NOTE: Ignored message types: AVOID_EXTERNS COMMIT_MESSAGE EMAIL_SUBJECT ENOSYS ENOSYS_SYSCALL FILE_PATH_CHANGES FROM_SIGN_OFF_MISMATCH GIT_COMMIT_ID MAINTAINERS PREFER_ATTRIBUTE_ALWAYS_UNUSED PREFER_DEFINED_ATTRIBUTE_MACRO QUOTED_COMMIT_ID SPDX_LICENSE_TAG STRCPY STRNCPY
> >>>
> >>> cppcheck had a few things to say, but none of it was about the changed
> >>> lines.
> >>>
> >>>> report is funny
> >>>>
> >>>>> int mount_service_main(int argc, char *argv[])
> >>>>> Warning
> >>>>> Poorly documented large function
> >>>>> Poorly documented function: fewer than 2% comments for a function of 113 lines.
> >>>>> CodeQL
> >>>
> >>> Hrmm.  I guess I'll have to figure out how to get those things running.
> >>> That said, the stuff in mount_service.c is internal to libfuse (i.e.
> >>> it's not public library API) so I didn't comment them as intensely.
> >>> Would you like more?
> >>>
> >>>> I think I'm going to merge my sync fuse init series tomorrow.
> >>>
> >>> Yay!
> >>>
> >>>> Are you ok if skip posting another version of the series?
> >>>
> >>>                ^ is there an "I" here?  e.g. "...if I skip posting..."?
> >>>
> >>> /My/ normal practice (from xfs) was to repost the series as it was
> >>> merged, followed by an announcement.  That way the mailing list is a
> >>> complete record of what was merged.  However, very very few people
> >>> actually do that, even in the kernel.
> >>>
> >>> I'm ok with you not posting another version of the series.
> >>>
> >>>> Or do you prefer to review the recent changes and last piece I'm going
> >>>> to do tomorrow?
> >>>
> >>> Nah, just merge it.  I'll look over the changes once it's in the branch
> >>> and if there's anything weird, you or I or anyone else can send patches.
> >>> As long as you're not planning to tag it as a release, nothing's set in
> >>> stone.
> >>>
> >>>> Basically my goal is to rebase your series against it immediately and
> >>>> to merge your series during the next few days.
> >>>
> >>> <nod> Let me know what you want changed, I'll be around since I am not
> >>> travelling anywhere for a couple of weeks. :)
> >>>
> >>> I can reflow changes into the patchset, or if you'd prefer, I can add
> >>> them as new patches that would go on the end of the series.
> >>>
> >>
> >> Hi Darrick,
> >>
> >> eventually merged my patches and made a quick rebase and conflict 
> >> resolving with your branch. Github still reports plenty of issues ;)
> >>
> >> Could you fix all of the checkpatch isssues? This one shows plenty
> >> "util: hoist the fuse.conf parsing and setuid mode enforcement code"
> >>
> >> bschubert2@imesrv6 libfuse.git>stg series
> >> + mount_service-add-systemd
> >> + mount_service-create-high
> >> + mount_service-use-the-new
> >> + mount_service-update-mtab
> >>> util-hoist-the-fuse.conf
> >> - util-fix-checkpatch-complaints
> >> - mount_service-enable
> >> - mount.fuse3-integrate-systemd
> >> - mount_service-allow
> >> - example-service_ll-create-a
> >> - example-service-create-a
> >> - nullfs-support-fuse-systemd
> >> - meson-show-feature-summary
> >> bschubert2@imesrv6 libfuse.git>.github/workflows/run-checkpatch.sh 
> >> No typos will be found - file '/home/bschubert2/src/libfuse/libfuse.git/spelling.txt': No such file or directory
> >> No structs that should be const will be found - file '/home/bschubert2/src/libfuse/libfuse.git/const_structs.checkpatch': No such file or directory
> >> ERROR:GLOBAL_INITIALISERS: do not initialise globals to 0
> >> #61: FILE: util/fuser_conf.c:33:
> >> +int user_allow_other = 0;
> >>
> >> WARNING:LINE_SPACING: Missing a blank line after declarations
> >> #74: FILE: util/fuser_conf.c:46:
> >> +	char *dest = buf;
> >> +	while (1) {
> > 
> > Oh!  The checkpatch fixes are all in the next commit
> > "util-fix-checkpatch-complaints".  I kept the checkpatch fixes as a
> > separate commit so that the hoist change can be inspected more easily.
> 
> That is not going to work, the script it set up to check every commit in
> the PR branch.

In that case, please just squash them together with:

$ stg squash -n util-hoist-the-fuse.conf util-hoist-the-fuse.conf util-fix-checkpatch-complaints

> > 
> > (XFS practice is to have separate patches for moving the code and
> > cleaning it up)
> > 
> >> ...
> >>
> >> I don't have a strong opinion about these two above - feel 
> >> free to disable them. However, in order to merge it, it would
> >> be good to run without any checkpatch report.
> >> And everything that cppcheck and gcc-checker reports, definitely 
> >> need to be fixed.
> > 
> > Hrm, should I try to fix the things that cppcheck complains about in
> > HEAD?  There's an awful lot of them...
> > 
> > (oh, I see you pushed to master, I'll go rebase now)
> 
> I had already rebased:
> 
> https://github.com/bsbernd/libfuse/tree/fuse-service-container

Oh!  Ok, I'll rebase against that, then.

--D