Re: [PATCH 0/7] fix up issues from djwong/fuse4fs-fork

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

On Mon, May 04, 2026 at 07:32:54PM -0400, Theodore Ts'o wrote:
> These are the patches that I've applied to the next branch to clean up
> found when trying to compile e2fsprogs on MacOS and via the github's
> continuous integration testing.
> 
> Note: See .github/workflows/ci.yaml; it's a good reason to get a
> github account if you are doing a lot of e2fsprogs development.
> If you fork my e2fsprogs repository and push your changes to your github
> repo, you can get reports like the ones found here:
>       https://github.com/tytso/e2fsprogs/actions
> 
> 
> Anyway, with these patches, e2fsprogs builds on MacOS (both using the
> github CI and on locally on my Macbook).  Unfortunately fuse2fs has
> regressed in that non-root accesses are getting denied with a permission
> denied on MacOS, and this worked with e2fsprogs v1.47.4.  Here's a
> lightly edited transcript from my Macbook Air:

Hm, curious.  It's regrettable that I no longer have a Mac, and
therefore can't really do much investigating.  If you give
-o default_permissions,allow_other , does that fix the problem?
If that fixes it, then fuse2fs has a bug somewhere in its own
permissions checking.

> % uname -a
> Darwin macsyma.local 25.4.0 Darwin Kernel Version 25.4.0: Thu Mar 19 19:33:09 PDT 2026; root:xnu-12377.101.15~1/RELEASE_ARM64_T8112 arm64 arm Darwin
> % ./mke2fs -Fq -t ext4 -d . /tmp/foo.img  1G
> % ./fuse2fs -o allow_other /tmp/foo.img /Users/tytso/mnt
> FUSE2FS (foo.img): Warning: fuse2fs does not support using the journal.
> There may be file system corruption or data loss if
> the file system is not gracefully unmounted.
> % stat /Users/tytso/mnt/revoke.o
> stat: cannot stat '/Users/tytso/mnt/revoke.o': Permission denied
> % sudo stat /Users/tytso/mnt/revoke.o
>   File: /Users/tytso/mnt/revoke.o
>   Size: 29728     	Blocks: 64         IO Block: 16384  regular file
> Device: 55,270	Inode: 91          Links: 1
> Access: (0644/-rw-r--r--)  Uid: (15806/   tytso)   Gid: (   20/   staff)
> Access: 2026-05-05 00:21:50.000000000 +0200
> Modify: 2026-05-05 00:21:50.000000000 +0200
> Change: 2026-05-05 00:21:50.000000000 +0200
>  Birth: -
> % stat revoke.o
>   File: revoke.o
>   Size: 29728     	Blocks: 64         IO Block: 4096   regular file
> Device: 1,18	Inode: 851374      Links: 1
> Access: (0644/-rw-r--r--)  Uid: (15806/   tytso)   Gid: (   20/   staff)
> Access: 2026-05-05 00:21:50.903084819 +0200
> Modify: 2026-05-05 00:21:50.346338295 +0200
> Change: 2026-05-05 00:21:50.346580544 +0200
>  Birth: 2026-05-05 00:21:50.293229053 +0200
> % sum revoke.o
> 45116    30 revoke.o
> % sum /Users/tytso/mnt/revoke.o
> sum: /Users/tytso/mnt/revoke.o: Permission denied

That's really strange.  Does MacOS do any strange idmapping stuff?

I'm also curious if there's a particular commit that makes it all work
again?  There are a few defaults that changed between fuse2 and fuse3,
and since MacFuse claims to have vendored both, it could very well be
the megacommit dropping the fuse2 api support.

--D

> So fuse2fs is broken on MacOS, but it's not *totally* broken, since you
> can still use it as root.  I'll want to fix this before updating the
> master branch, but this is good enough for the next branch.
> 
> 
> 
> Theodore Ts'o (7):
>   libsupport: drop xbitops.h and define fls() if necessary
>   configure.ac: fix disable fuse2fs/fuse4fs by default path
>   libsupport: don't use bzero in cache.c
>   fuse[24]fs: suppress clang warnings which were breaking the github CI
>   libsupport: remove the LIST_HEAD macro from list.h
>   libsupport: fix gcc -Wall warnings
>   fuse2fs: fix uninitialized variable warnings
> 
>  configure               |   8 +++
>  configure.ac            |   3 +
>  fuse4fs/Makefile.in     |  18 +++---
>  fuse4fs/fuse4fs.c       |  29 +++++++--
>  lib/config.h.in         |   3 +
>  lib/support/Makefile.in |   2 +-
>  lib/support/cache.c     |  49 ++++++++++++---
>  lib/support/cache.h     |   2 +-
>  lib/support/list.h      |  17 ++++--
>  lib/support/xbitops.h   | 128 ----------------------------------------
>  misc/fuse2fs.c          |  21 +++++++
>  11 files changed, 125 insertions(+), 155 deletions(-)
>  delete mode 100644 lib/support/xbitops.h
> 
> -- 
> 2.53.0
> 
>