Bug#951208: Impossible to mount over nonempty directories
Package: bindfs
Followup-For: Bug #951208
bindfs -o nonempty ... works for me after today's fuse3 update to 3.10.1-3,
which is patched per #939767 ("fuse3: Installing fuse3 breaks fuse2 applications
using -o nonempty").
Bug#951208: Impossible to mount over nonempty directories
Package: bindfs Version: 1.14.7-1 Followup-For: Bug #951208 On 18/02/2020 14:07, Eugene V. Lyubimkin wrote: > How common of a use case is to use bindfs with a non-empty mount point? I > never mounted filesystems like that myself, so > I don't know if it's a minor nuisance with an easy workaround, or a > significant limitation making some use case > unachievable. I use bindfs to redirect heavy I/O away from my SSD from the Firefox cache, when visiting some specific sites, because it does not support XDG_CACHE_HOME: https://bugzilla.mozilla.org/show_bug.cgi?id=259356 On 21/02/2020 10:02, Willem Mulder wrote: > At our association we have shared home directories (over NFS), but on > one particular server, our remote desktop server, we have the XDG > config, data and cache directories on separate HDDs. We're using bindfs > to mount them onto their default locations, since not all software uses > the XDG environment variables. People can also run software on other > servers, so we do need (the ability) to mount over nonempty directories. If that can be helpful, the arch wiki has a comprehensive list of apps that do not follow the XDG spec, or follow it in part: https://wiki.archlinux.org/index.php/XDG_Base_Directory
Bug#951208: fuse3's backwards compatibilty (Re: Bug#951208: Impossible to mount over nonempty directories)
Hi, On 18/02/2020 14:07, Eugene V. Lyubimkin wrote: > How common of a use case is to use bindfs with a non-empty mount point? I > never mounted filesystems like that myself, so > I don't know if it's a minor nuisance with an easy workaround, or a > significant limitation making some use case > unachievable. At our association we have shared home directories (over NFS), but on one particular server, our remote desktop server, we have the XDG config, data and cache directories on separate HDDs. We're using bindfs to mount them onto their default locations, since not all software uses the XDG environment variables. People can also run software on other servers, so we do need (the ability) to mount over nonempty directories. Kind regards, Willem Mulder signature.asc Description: OpenPGP digital signature
Bug#951208: fuse3's backwards compatibilty (Re: Bug#951208: Impossible to mount over nonempty directories)
I've used non-empty mountpoints a few times, mostly when mounting a directory onto itself, but I have no idea how popular that use case really is. Mounting to a new empty location is probably always possible, but it's sometimes quite undesirable or inconvenient: - Sometimes I want to enforce certain rules on a directory and hide the original directory to prevent confusion and misuse. - Sometimes I want to quickly test something on an existing directory, and a program I want to use might be configured or even hard-coded to use that specific directory. So I think this is worth fixing. Here's my current understanding (I was a bit confused in my initial response): - The scope: bindfs seems to work fine with libfuse2 and fuse3 EXCEPT for `nonempty`. The test suite, which tests most other features, passes on Debian 10 with fuse3 installed. - The bug: libfuse2 checks that the destination is empty or `nonempty` is given. Then it invokes fusermount (symlinked to fusermount3), which doesn't accept `nonempty`. - bindfs cannot be compiled against libfuse3. That would require significant code changes. So it seems backwards compatibility between fusermount3 and libfuse2 was intended, and this is a bug there. If so, here are the "easy" fixes I can think of: 1. patch fusermount3 to accept and ignore `nonempty` (perhaps only when invoked through a symlink named fusermount?) or 2. patch libfuse2 to stop requiring `nonempty` (or passing it to fusermount when it's symlinked to fusermount3?) or 3. instead of symlinking fusermount -> fusermount3, make it a wrapper script that drops `nonempty` from any option list like `-o option1,nonempty,option2,...` If someone who knows FUSE better can point out something simple I can do in bindfs code instead, I'd be happy to write a short patch. But there may be other FUSE 2 filesystems designed to "wrap" an existing directory that also have this bug, so I think fixing this at the FUSE layer is better. On Tue, 18 Feb 2020 at 15:12, Eugene V. Lyubimkin wrote: > Hello, > > Martin Pärtel kirjoitti 17.2.2020 klo 10.49: > > I'm unfortunately unlikely to have time to port bindfs to FUSE 3 in the > near future :( > > > > The easiest distro-level workaround in terms of "least code required" > would probably be to patch fuse3's fusermount to > > allow and ignore `nonempty` (and maybe print a deprecation warning). Or > some hacks could probably be invented to direct > > FUSE 2 filesystems to use FUSE 2 helpers. It's up to the Debian > maintainers whether they want the maintenance burder of > > either of these workarounds. > > CC'ing FUSE's maintainer for extra input if any. > > > From the discussion above I gather that bindfs is still (with limitations) > usable with fuse3. If true, then I wouldn't > like to block users of fuse3 from using bindfs via strict Depends. I could > add Suggests or Recommends on fuse2, > though. > > How common of a use case is to use bindfs with a non-empty mount point? I > never mounted filesystems like that myself, so > I don't know if it's a minor nuisance with an easy workaround, or a > significant limitation making some use case > unachievable. > > > Regards, > -- > Eugene V. Lyubimkin aka JackYF > C++ GNU/Linux userspace developer, Debian Developer > >
Bug#951208: fuse3's backwards compatibilty (Re: Bug#951208: Impossible to mount over nonempty directories)
Hello, Martin Pärtel kirjoitti 17.2.2020 klo 10.49: > I'm unfortunately unlikely to have time to port bindfs to FUSE 3 in the near > future :( > > The easiest distro-level workaround in terms of "least code required" would > probably be to patch fuse3's fusermount to > allow and ignore `nonempty` (and maybe print a deprecation warning). Or some > hacks could probably be invented to direct > FUSE 2 filesystems to use FUSE 2 helpers. It's up to the Debian maintainers > whether they want the maintenance burder of > either of these workarounds. CC'ing FUSE's maintainer for extra input if any. >From the discussion above I gather that bindfs is still (with limitations) >usable with fuse3. If true, then I wouldn't like to block users of fuse3 from using bindfs via strict Depends. I could add Suggests or Recommends on fuse2, though. How common of a use case is to use bindfs with a non-empty mount point? I never mounted filesystems like that myself, so I don't know if it's a minor nuisance with an easy workaround, or a significant limitation making some use case unachievable. Regards, -- Eugene V. Lyubimkin aka JackYF C++ GNU/Linux userspace developer, Debian Developer
Bug#951208: Impossible to mount over nonempty directories
Ok, thanks. If you don't use other FUSE filesystems, you can maybe uninstall `fuse3` and install `fuse`. I'm unfortunately unlikely to have time to port bindfs to FUSE 3 in the near future :( The easiest distro-level workaround in terms of "least code required" would probably be to patch fuse3's fusermount to allow and ignore `nonempty` (and maybe print a deprecation warning). Or some hacks could probably be invented to direct FUSE 2 filesystems to use FUSE 2 helpers. It's up to the Debian maintainers whether they want the maintenance burder of either of these workarounds. On Wed, 12 Feb 2020 at 18:07, Willem Mulder wrote: > Hi Martin, > > On Wed, 2020-02-12 at 17:17 +0200, Martin Pärtel wrote: > > If that doesn't help, maybe you're running a mixed environment where > > e.g. bindfs is compiled against FUSE 2 but the system runs FUSE 3 > > helper binaries? The version list at the end of your e-mail suggests > > this. > > I haven't used your option, but I can confirm (using `ldd > /usr/bin/bindfs` and `fusermount -V`) that bindfs was linked against > libfuse 2.9.9, and the helper binaries are version 3.7.0. I guess the > package either needs to limit the FUSE version to < 3, or link against > libfuse >= 3. > > Kind regards, > > Willem Mulder >
Bug#951208: Impossible to mount over nonempty directories
Hi Martin, On Wed, 2020-02-12 at 17:17 +0200, Martin Pärtel wrote: > If that doesn't help, maybe you're running a mixed environment where > e.g. bindfs is compiled against FUSE 2 but the system runs FUSE 3 > helper binaries? The version list at the end of your e-mail suggests > this. I haven't used your option, but I can confirm (using `ldd /usr/bin/bindfs` and `fusermount -V`) that bindfs was linked against libfuse 2.9.9, and the helper binaries are version 3.7.0. I guess the package either needs to limit the FUSE version to < 3, or link against libfuse >= 3. Kind regards, Willem Mulder
Bug#951208: Impossible to mount over nonempty directories
Hi Willem, The only reference to "nonempty" in binds code is when a directory is mounted on itself. In that case bindfs adds `-ononempty` automatically. I changed it so it doesn't on FUSE 3: https://github.com/mpartel/bindfs/commit/2c2337b7c9b87744662c4b08d453bf7128444f43 (git master, not in a release yet) If that doesn't help, maybe you're running a mixed environment where e.g. bindfs is compiled against FUSE 2 but the system runs FUSE 3 helper binaries? The version list at the end of your e-mail suggests this. I added an option that may help you debug that: https://github.com/mpartel/bindfs/commit/4b87500fef925e591b08cb8aea6bf0a21b84dd72 Let me know if I can help further. On Wed, 12 Feb 2020 at 16:27, Willem Mulder wrote: > Package: bindfs > Version: 1.14.1-1 > Severity: normal > File: /usr/bin/bindfs > > Dear Maintainer, > > Currently, it's not possible for me to mount over nonempty directories. > BindFS insists I have to use -o nonempty: > > fuse: mountpoint is not empty > fuse: if you are sure this is safe, use the 'nonempty' mount option > > But when I do, I get the following message: > > fusermount: unknown option 'nonempty' > > Some quick searching suggests this might have to do with upgrading to > FUSE 3: https://github.com/rclone/rclone/issues/3562 > > Kind regards, > > Willem Mulder > > -- System Information: > Debian Release: bullseye/sid > APT prefers testing > APT policy: (990, 'testing'), (500, 'testing-debug'), (500, 'unstable'), > (500, 'stable') > Architecture: amd64 (x86_64) > Foreign Architectures: i386 > > Kernel: Linux 5.4.0-3-amd64 (SMP w/16 CPU cores) > Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8), > LANGUAGE=en_IE.UTF-8 (charmap=UTF-8) > Shell: /bin/sh linked to /bin/dash > Init: systemd (via /run/systemd/system) > LSM: AppArmor: enabled > > Versions of packages bindfs depends on: > ii fuse3 [fuse] 3.7.0-1 > ii libc6 2.29-10 > ii libfuse2 2.9.9-2 > > bindfs recommends no packages. > > bindfs suggests no packages. > > -- no debconf information > >
Bug#951208: Impossible to mount over nonempty directories
Package: bindfs Version: 1.14.1-1 Severity: normal File: /usr/bin/bindfs Dear Maintainer, Currently, it's not possible for me to mount over nonempty directories. BindFS insists I have to use -o nonempty: fuse: mountpoint is not empty fuse: if you are sure this is safe, use the 'nonempty' mount option But when I do, I get the following message: fusermount: unknown option 'nonempty' Some quick searching suggests this might have to do with upgrading to FUSE 3: https://github.com/rclone/rclone/issues/3562 Kind regards, Willem Mulder -- System Information: Debian Release: bullseye/sid APT prefers testing APT policy: (990, 'testing'), (500, 'testing-debug'), (500, 'unstable'), (500, 'stable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 5.4.0-3-amd64 (SMP w/16 CPU cores) Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8), LANGUAGE=en_IE.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages bindfs depends on: ii fuse3 [fuse] 3.7.0-1 ii libc6 2.29-10 ii libfuse2 2.9.9-2 bindfs recommends no packages. bindfs suggests no packages. -- no debconf information
