Hi! On Wed 2012-09-19 20:01:10, Theodore Ts'o wrote: > On Thu, Sep 20, 2012 at 01:23:49AM +0200, Pavel Machek wrote: > > > > I'm not sure I agree. > > > > If you treat root fs as removable, you'll get "crash". You'll need to > > replay the journal, but data is safe. > > > > If you treat it as non-removable, and someone manages to remove it, > > mount, and reinsert, you'll get silent data corruption. > > We could detect this case; if the file system gets mounted, the last > mount time will change. So one of the things we could do is have the > file system code freeze the file system at suspend time, so the file > system is consistent (which will reduce the probability of data loss > if the system never comes back up after the suspend), and save the > last mount time and last write time in memory. When the system comes > back from resume, have the file system code check the last mount and > last write time, and if they have changed, it can refuse the resume > and abort the system to avoid data corruption. It would require > making ext3/ext4 suspend-aware, but it would be doable, if we really > wanted to support this. Yes please; I'd love to see this done. We used to do sync() to get filesystem in consistent state, and I believe that these days we are doing filesystem freeze; but code validating the last mount time is certainly missing. Looking forward, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
