Re: nullfs and ZFS issues

From: Doug Ambrisko <ambrisko_at_ambrisko.com>
Date: Wed, 20 Apr 2022 16:20:33 UTC 
On Wed, Apr 20, 2022 at 11:39:44AM +0200, Alexander Leidinger wrote:
| Quoting Doug Ambrisko <ambrisko@ambrisko.com> (from Mon, 18 Apr 2022  
| 16:32:38 -0700):
| 
| > With nullfs, nocache and settings max vnodes to a low number I can
| 
| Where is nocache documented? I don't see it in mount_nullfs(8),  
| mount(8) or nullfs(5).

I didn't find it but it is in:
	src/sys/fs/nullfs/null_vfsops.c:  if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||

Also some file systems disable it via MNTK_NULL_NOCACHE

| I tried a nullfs mount with nocache and it doesn't show up in the  
| output of "mount".

Yep, I saw that as well.  I could tell by dropping into ddb and then
do a show mount on the FS and look at the count.  That is why I added
the vnode count to mount -v so I could see the usage without dropping
into ddb.

Doug A.