Am Wed, 29 Mar 2017 19:52:57 +0200 schrieb Kai Krakow <hurikhan77@xxxxxxxxx>: > Am Wed, 29 Mar 2017 14:27:11 +0200 > schrieb Clemens Eisserer <linuxhippy@xxxxxxxxx>: > > > Hi Kai, > > > > > As far as the docs tell, bcache is designed to shut down unclean. > > > So this is expected behavior in write-back mode. > > > > Yes, I also read it - but since I got a few btrfs fs errors when > > running btrfs check (mostly space-cache related) I became a bit > > alarmed. > > As all csums are ok, so I don't think the backing/caching devices > > are corrupt in any way. > > This is probably related to btrfs not closed properly or some bug in > an older kernel. Space cache problems can usually be safely ignored as > long as the kernel detects them. But maybe ask about this in the btrfs > list. I'm pretty sure that is related to your shutdown procedure and > not to bcache. I don't see such messages here without special > workarounds in the shutdown procedure, however, I'm using initramfs > created by dracut. It properly unmounts btrfs. > > > > To cleanly detach a bcache, you would need to first put it in > > > write-through or write-around mode and wait for write-back to > > > finish. In turn, this mode should also avoid these messages at > > > boot. > > > > This is exactly what I do now before each shutdown: switch to > > writethrough and wait in a bash-loop until state="clean" - > > sorrounded by two calls to sync. > > I don't think this is necessary. Just ensure that the FS is umounted > or at least RO mounted, sync, and ensure that all storage buffers are > flushed (SCSI, SATA, whatever). Btrfs may lazily still write data even > in the RO mounted mode. This may be your problem. Bcache may even > prevent further evil here because of its always-unclean writeback > behavior. Addendum: Maybe try "btrfs sync"... > > However, I still get the journal replay messages at bootup: > > > > [ 2.590615] bcache: bch_journal_replay() journal replay done, 827 > > keys in 37 entries, seq 145717 > > Do you properly close the FS before shutting down, i.e. unmount (and > not only remount RO), and flush the storage layer? > -- Regards, Kai Replies to list-only preferred. -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
