Re: [PATCH] net/samba4: relocate Sysvol to persist between reboots & move variable data out of /usr/pkg/etc/...

[Chuck Silvers <chuq%chuq.com@localhost>]

On Wed, Jul 29, 2020 at 06:13:03PM +0100, Chavdar Ivanov wrote:
> On Wed, 29 Jul 2020 at 08:33, Matthias Petermann <mp%petermann-it.de@localhost> wrote:
> >
> > Hello Chavdar,
> >
> > Am 28.07.2020 um 18:48 schrieb Chavdar Ivanov:
> > > This being a place people are trying samba4 as a DC, I got a
> > > repeatable panic on one of the systems I am trying it on, as follows:
> > > ....
> > > crash: _kvm_kvatop(0)
> > > Crash version 9.99.69, image version 9.99.69.
> > > Kernel compiled without options LOCKDEBUG.
> > > System panicked: /: bad dir ino 657889 at offset 0: Bad dir (not
> > > rounded), reclen=0x2e33, namlen=51, dirsiz=60 <= reclen=11827 <=
> > > maxsize=512, flags=0x2005900, entryoffsetinblock=0, dirblksiz=512
> > >
> > > Backtrace from time of crash is available.
> > > _KERNEL_OPT_NARCNET() at 0
> > > _KERNEL_OPT_DDB_HISTORY_SIZE() at _KERNEL_OPT_DDB_HISTORY_SIZE
> > > sys_reboot() at sys_reboot
> > > vpanic() at vpanic+0x15b
> > > snprintf() at snprintf
> > > ufs_lookup() at ufs_lookup+0x518
> > > VOP_LOOKUP() at VOP_LOOKUP+0x42
> > > lookup_once() at lookup_once+0x1a1
> > > namei_tryemulroot() at namei_tryemulroot+0xacf
> > > namei() at namei+0x29
> > > vn_open() at vn_open+0x9a
> > > do_open() at do_open+0x112
> > > do_sys_openat() at do_sys_openat+0x72
> > > sys_open() at sys_open+0x24
> > > syscall() at syscall+0x26e
> > > --- syscall (number 5) ---
> > > syscall+0x26e:
> > > ....
> >
> >
> > that still looks like a file system inconsistency. Before the patch from
> > Chuck I also had the case several times that a filesystem that was
> > apparently repaired with fsck could no longer be trusted. After
> > importing the patched kernel, to be on the safe side, I recreated all
> > the file systems previously mounted with posix1eacls with newfs.
> 
> Hard that one, as it was the root file system... Anyway, a couple of
> fsck's seem to have sorted out this one.

how exactly did you run fsck to fix this?  the most reliable way is to boot
the machine single-user, then run "fsck -fy ..." from the console shell,
then run the same fsck command again to make sure that it says that
everything is ok, then reboot.

if you have done that and are still crashing due to corruption in your
root file system, then we still have another bug in the kernel somewhere.


> > Presumably fsck is not prepared for the kind of inconsistency, and only
> > a newfs can restore a trustworthy initial state. What is the starting
> > point for you? Has the file system been created after the patch, or has
> > it only been treated with fsck so far?
> 
> I think it may have been created before the patch to the filesystem
> code, but before the second version of the samba4 package.
> 
> >
> > In any case, I would advise you - if you have not already done so - to
> > use a separate partition or LVM volume for the sysvol with its own file
> > system, and to mount only this with the posix1eacls option. It seems the
> > ACL code still needs a lot of testingh, so at least you can be sure that
> > your root filesystem will not be affected.
> 
> As this was running on a XCP-NG guest, I added a small 1GB disk to the
> vm, created the filesystem (-O 2) and mounted it on /var/db/samba4.
> 
> I removed the 'posix1eacls' options from the other existing
> filesystems and left it only for the one mounted on /var/db/samba4 .
> In this case, the provisioning fails with a message that the
> filesystem does not support acls - so it perhaps checks  the root
> filesystem after all. I then re-added this option to /, newfs'd
> /var/db/samba4, rebooted and retried the provisioning. This resulted
> in a similar to the above panic, this time after perhaps 10 minutes
> work of python8 doing database conversion from v1 to v2 - the third
> database in the list. As this was seen on the console of the XCP-NG
> guest, I took screenshots of the panic, in case someone is interested.

yes, I'd like to see the screenshots please.

-Chuck