Hello Ben, I am not following the list closely, but I noticed you are having troubles unmounting your fs, which is an aufs branch.
Here are few notes: - I think you're using aufs as root filesystem. A root filesystem can't be unmounted, only remounted read-only (which is enough) - as Junjiro explained, you have to (first) remount all aufs branches ro, and then all underlaying mountpoints ro - if you reboot without remounting your USB ro, then you'll get data corruption, as you probably experienced - a filesystem (any filesystem, including your /cow) can be remounted readonly ONLY if there are no files open from it - if I remember correctly, aufs uses XINO file, which is a hidden file on your first writable branch. If your first writable branch is your /cow then even if you remount your aufs ro, the xino file remains open and your /cow can't be remounted ro Suggestions: 1) when you mount your aufs, set XINO path somewhere in tmpfs in memory, instead of on your /cow filesystem 2) If you have problems remounting /cow readonly, eg. your mountpoint still remains rw even after remount, then you may use lsof to see which files are open on your mountpoint, disallowing it to go read-only. This will give you information why your mountpoint can't be remounted ro. 3) if you are using /bin/init to startup your system on aufs, then even the init binary may have some files opened on your aufs. In this case you'll need to re-execute the init from somewhere else. This is tricky part, I did it in Slax by switch_root. Let me know if you think this is your case so I could perhaps explain in more detail if you need. 4) do not use 2>/dev/null redirection of stderr output - rather analyze the error output of your remount commands Tomas M slax.org On Thu, May 17, 2012 at 6:16 PM, Ben Greear <gree...@candelatech.com> wrote: > On 05/17/2012 12:47 AM, sf...@users.sourceforge.net wrote: >>> Ben Greear: >>>> What is the proper way to clean this all up on reboot >>>> so that /cow is properly flushed and un-mounted (and >>>> thus clean for mount on startup w/out having to fsck it)? >>>> >>>> I tried hacking the 'umountroot' script that is supposed >>>> to make / mounted (ro), by adding >>>> >>>> mount -o remount,del:/cow / after it was (ro), >>>> but that doesn't seem to work. >>> >>> I am afraid you might be still misunderstanding. >>> As well as you cannot unmount the root dir, you cannot remove last >>> branch from aufs. >>> Setting RO is the substitution of unmounting. If you set the aufs branch >>> as RO, you don't have to unmount it anymore. >> >> I should be more precise. >> "Setting RO" means both of these. >> - for aufs, "remount,mod:/brabra=ro" >> - for native fs, "remount,ro" > > I tried to set it ro in both ways, and it appears neither work. > Here is the code I am using. When I do that last 'cat /proc/mounts', > /cow is still mounted (rw), and if you fsck the backing store > for /cow on the next bootup, it is dirty. > > I can upload an image that you can dd to a usb drive to > test this yourself if you wish. > > MOUNT_FORCE_OPT= > [ "$(uname -s)" = "GNU/kFreeBSD" ] && MOUNT_FORCE_OPT=-f > # This: > # mount -n -o remount,ro / > # will act on a bind mount of / if there is one. > # See #339023 and the comment in checkroot.sh > sync > set -x > auplink / flush > mount $MOUNT_FORCE_OPT -n -o remount,ro -t dummytype dummydev / > 2>/dev/null \ > || mount $MOUNT_FORCE_OPT -n -o remount,ro dummydev / > 2>/dev/null \ > || mount $MOUNT_FORCE_OPT -n -o remount,ro / > ES=$? > sync > [ "$VERBOSE" = no ] || log_action_end_msg $ES > > if [ -d /cow ] > then > # Remove from aufs > # This doesn't actually seem to work. > MOUNT_FORCE_OPT=-f > mount $MOUNT_FORCE_OPT -n -o remount,mod:/cow=ro / > mount $MOUNT_FORCE_OPT -n -o remount,del:/cow / > mount $MOUNT_FORCE_OPT -n -o remount,ro /cow > umount $MOUNT_FORCE_OPT -n /cow > fi > cat /proc/mounts > > # Give usb persistent storage a chance to calm down?? > sleep 10 > > > Thanks, > Ben > > -- > Ben Greear <gree...@candelatech.com> > Candela Technologies Inc http://www.candelatech.com > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
