[Filesystems-devel] Bug#1025791: fsck.f2fs is unable to check mounted FS

[Theodore Ts'o]

On Fri, Dec 09, 2022 at 11:16:46AM +0300, Michael Tokarev wrote:
> Package: f2fs-tools
> Version: 1.14.0-2
> Severity: important
> 
> When running an fsck.f2fs on a readonly-mounted filesystem (root filesystem
> for example, which obviously can not be unmounted), fsck.f2fs always fails:
> 
> I don't know if this is a kernel issue (who explicitly prevents
> opening of a mounted block device) or f2fs-tools issue (who is
> not doing any special actions required to work around that), but
> the result is that the root filesystem is never checked for errors,
> and the boot process always complains about failed fsck.
> 
> Other filesystems (eg ext*fs) is able to check and repair a mounted
> (read-only) filesystem just fine.
> 
> This is why I think this bug is of Severity: important.  The only way
> to check f2fs root  filesystem for errors is to put fsck.f2fs into
> initramfs and go from there, or boot some rescue media.

Well, btrfs and xfs have /sbin/fsck.$FSTYP which is a no-op when it is
run with the -a option.  Whether or not this is a good idea is
something where I have my own opinions ---- but as the ext4
maintainer, I'm obviously biased.  :-)

The point is that there are many many other file systems supported by
Debian which never checks the root file system for errors --- even if
you use an initramfs.

The other thing I'll note is that f2fs-tools isn't getting much love
in Debian at the moment.  The original maintainer/uploader was Vincent
Cheng, and I joined the Filesystem Group to help out mainly because I
wnated to get an updated f2fs-tools for kernel testing[1].  I don't
actually use f2fs except for kernel testing, so I wouldn't want to be
making changes to f2fs-tools or its support scripts, since I might not
notice any potential problems.

[1] https://thunk.org/gce-xfstests

So if you or other folks would be interested in helping with
f2fs-tools, especially if you are actually interested in using f2fs as
a root file system, please consider joining the file system group and
helping out.  There is new version of f2fs-tools that hasn't been
packaged yet and I'm not sure when I will have the time....

	     	     	      	   - Ted