Btrfs for Rawhide users?

Posted Nov 23, 2009 22:08 UTC (Mon) by oak (guest, #2786)
In reply to: Btrfs for Rawhide users? by masoncl
Parent article: Btrfs for Rawhide users?

> It's a fun problem...to answer another question I see farther down, can
we easily recover the space from old snapshots deleted, yes.

And if running processes are still keeping files open from the old state
of the file system (like previous version of the C-library kept open by
every process mmap), what do you do?

Kill all those process when deleting the old snapshot? Tell that snapshot
is busy and cannot be deleted and just list processes or recommend reboot
to get rid of them?

a file which a process holds open is still an inode in the mounted fs, even if no filename points to it.

Posted Nov 27, 2009 3:29 UTC (Fri) by xoddam (subscriber, #2322) [Link]

If running processes have files open which have been removed from their original *directories* and replaced by new files at the same pathnames by package updates, the old *inodes* will still be in the *current* filesystem until such time as the running processes close the files.

This 'just works' even in the absence of snapshots.

With snapshots, it means the disk space in question won't be reclaimable when old snapshots are removed, but it won't stop the snapshots themselves from being removed. The space will become reclaimable only when the data is no longer in use -- i.e. when the inode is no longer open in the live, mounted filesystem.