Re: Is is reasonable to support quota in fuse?

["Theodore Ts'o" <tytso@mit.edu>]

On Wed, Jun 05, 2024 at 12:29:45PM +0200, Jan Kara wrote:
> 
> But that's why I'm asking for usecases. For some usecases it may be fine
> that in case of unclean shutdown you run quotacheck program to update quota
> information based on current usage - non-journalling filesystems use this
> method. So where do you want to use quotas on a FUSE filesystem?

Something else to consider is whether you want to allow the user to
query the current quota information (e.g., the "quota" command), and
whether you want the system administrator to be able to set quota
limits, and whether you expect that when the soft quota limits are
exceeded that warnings get written to the user's tty.  All of this
would mean that the kernel fuse driver would need changes, and the
kernel<->userspae FUSE protocol would need to be extended as well.
And at that pointm you really want to get the FUSE maintainer
involved, since the FUSE protocol is somethign which is used on other
OS's (e.g., Windows, MacOS, etc.)

As Jan put it, it's all in the use cases that you expect to be able to
support.  If you just want quota to be tracked, and for certain writes
to return EDQUOT, that's one thing.  If you want the full Linux quota
user experience, that's quite another.

Cheers,

						- Ted