[CRIU] [PATCH 0/2] introduce --skip-mnt cli option

[Oleg Nesterov]

Hello.

To clarify: this depends on "[PATCH 0/5] parse_mountinfo: minor fixes
and cleanups" series I sent before. But this is completely orthogonal
to FSTYPE__AUTO feature we discuss in another thread, this series can
be applied (or nacked ;) independently.

With this patch (plus FSTYPE__AUTO hacks) I can finally dump/restore

	perl -e 'close STDIN; close STDOUT; close STDERR; sleep'

running with the unshared mnt ns on rhel-7 which has a lot of mounts
by default.

"--enable-fs all" helps to dump xfs/configfs/more, but it obviously
can't handle "autofs". Now I can pass --skip-mnt /proc/sys/fs/binfmt_misc
to make it work.

And I am very sure that mysqld (the actual target I want to c/r) doesn't
need this mountpoint, so I think I have the use-case ;)

Please review. Again, again, I mostly mean the feature itself.



As for implementation, see the changelog in 2/2. I think that we should
filter out the mounts at "parse" time, but I am not sure you will like
this.

Say, if I pass "--skip-mnt /sys" then mnt_build_tree() right after that
correctly fails with "Mountpoint w/o parent" and this is what we want.
So at least I think we should not postpone the filtering "too much".

TODO:

	- support this option in RPC.

	- perhaps --skip-fsname makes sense too. Or, better, we can
	  teach add_skip_mount() to check "fs=" or "mnt=" at the start
	  of optarg.

Oleg.