fs/squashfs: Add the squashfs file system

[chuck]

Summary

Add a kernel file system driver for SquashFS. This was done as a part
of a Google Summer of Code project.

Relnotes: yes
Sponsored by: Google LLC (GSoC 2023)
Co-authored-by: Kyle Evans <[e-mail]>

[ziaee]

share/man/man4/squashfs.4

2–27

29

35–46

See vt, iwx, and some others.

Would we need to load this in early boot instead of rc.conf?

This has no kernel tunable options or sysctls?

51

Since this is a freebsd driver, freebsd is redundant here.
Roff needs one sentence per line.

Can it just mount and access them? Is creating possible?

55–60

+ .Pa lets people use apropos Pa=sqfs
+ putting the root prompt breaks copy paste and is implied for mount, you typically only want to use them for a complex multi line example where only some parts should be ran as root.

75

No blank lines in Roff

[chuck]

share/man/man4/squashfs.4

29

Du-oh!!

35–46

I could imagine both needing this driver at early boot as well as later in rc.conf

And correct, no tunables or system controls at the moment.

51

Does this work better:

The squashfs driver provides support for mounting and accessing SquashFS compressed file system images.
SquashFS is a compressed read-only file system designed for general read-only file system use in constrained block device/memory systems.
Use a program like mksquashfs or gensquashfs to create a suitable image.

Should the man page annotate mksquashfs and gensquashfs in any particular manner?

[ziaee]

share/man/man4/squashfs.4

51

Yes, I really like that! I have no preference on order, but please use
.Sy utility
Or if possible
.Xr utility 8.

[chuck]

Address doc feedback

[imp]

share/man/man4/squashfs.4

40

Are either of the generators ports?

[ziaee]

Oh, and I /think/ you need a man4/Makefile addition

share/man/man4/squashfs.4

33

[chuck]

share/man/man4/squashfs.4

40

Yes, both are in ports. It didn't sound like there was a standardized way to link to those, but perhaps I misunderstood.

[ziaee]

Usually what doc does is

.Xr thing 1
.Pq Pa ports/category/thing

But ports doesn't like that because iiuc the category can change, but I think the utility of this notation is high enough that I'd rather just change it when it changes.