Hi! > While working on freezing fuse filesystems, I found that if a filesystem > is frozen when we try to freeze processes, freezing can fail because > threads are waiting in vfs_check_frozen for the filesystem to be thawed. > We should thus not count such threads. > > The check will be safe if a filesystem is thawed while we're freezing > processes because filesystem thaws are only invoked from userspace. Any > waiting processes will be woken and frozen prior to us completing the > freezing of userspace (the caller invoking the filesystem thaw will be > freezing) or - in the worst case - together with kernel threads. In the worst case we have a problem. Userspace and kernel threads *need* to be frozen separately... (Otherwise its a race, and if you freeze kjournald first, user process becomes unfreezeable and freezing fails.) Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
