clone 768406 -1 -2 reassign -1 cgmanager retitle -1 Should honor umount to allow filesystem operations like e2fsck (at least in default install) severity -1 important reassign -2 lsof retitle -2 Please show filesystems used by cgmanager for tracking severity -2 wishlist thanks
Hello Ted, On Wed, Nov 12, 2014 at 03:38:14PM -0500, Theodore Ts'o wrote: > On Wed, Nov 12, 2014 at 08:31:49PM +0100, Helge Kreutzmann wrote: > So cgmanager is different from systemd. In fact, it's not clear in th > elong term whether systemd and cgmanager will play well together. Thanks for the explanation. At least I did not install it on purpose. > > Secondly should this bug be assigned to cgmanager? > > Well, what it is doing is documented: > > "This daemon (cgmanager) runs on the host, mounts cgroupfs into a > separate mount namespace (so it's invisible from the host), binds > /sys/fs/cgroup/cgmanager/sock for incoming DBus queries and generally > handles all clients running directly on the host." -- > https://cgmanager.linuxcontainers.org/ > > The net effect is that if you start cgmanager, since it create a > separate mount namespace, any file systems which are mounted at the > time when cgmanager is started will still be mounted in the cgmanager > namespace: > > # mount -t ext4 /dev/heap/bitcoin /bitcoin > # service cgmanager start > # umount /dev/heap/bitcoin > # e2fsck -p /dev/heap/bitcoin > /dev/heap/bitcoin is in use. > e2fsck: Cannot continue, aborting. > > # service cgmanager stop > # e2fsck -p /dev/heap/bitcoin > /dev/heap/bitcoin: clean, 15913/4587520 files, 14937110/18350080 blocks > > Whether or not this is a _bug_ is a bit debateable. It is a natural > consequences of its documented (and intentional) behavior. Granted it > is has some very confusing and someone user-unfriendly consequences. > So, if you want try to reassign this to the cgmanager package, it's > not unreasonable. But it's likely that any "fix" will require some > pretty serious design discussions with its upstream developers. Thanks for the verbose explanation. I believe on default install (probably due to a suggests: from a different package as in my case) this is a bug. Unless I wilingly configure namespaces I expect basic tools like e2fsck to remain operational (in the sense that I can easily use them, not in the sense that they are broken, as it is definitly not). I know the »easy« solution of a Debconf prompt upon installation is frowned upon, thus I cannot derive an easy fix myself. > > (And probably a wishlist bug for the kernel to offer a reliable means > > to detect mounted partitions?). > > Again, it's not unreasonable, but it's also the case that it's beyond > what the Debian kernel developers are likely to have the bandwidth and > mandate to try to "fix", since it requires a fairly fundamental > rearchitecture of how namespaces work. I've been grumbling about this > for years, and if there was an easy fix, it would have been fixed by > now. Well, I think at least lsof should be able to tell me about cgmanager, opening a wishlist bug there as well. I left this bug at e2fsprogs, feel free to deal with it as appropriate, e.g. close it. Thanks again very much for your help! Greetings Helge -- Dr. Helge Kreutzmann [email protected] Dipl.-Phys. http://www.helgefjell.de/debian.php 64bit GNU powered gpg signed mail preferred Help keep free software "libre": http://www.ffii.de/
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