On Sun, Mar 10, 2013 at 10:31:08PM -0700, Michael Johnson - MJ wrote: > I currently have a btrfs filesystem that I am unmounting and it has > been has been "unmounting" for the last 20 minutes. > > I'm pretty sure I know exactly what is going on and in my current > situation it's not a huge issues, but it would be a problem if this > was a production system and I was trying to do a maintenance. > > Here is how I got into this situation: > > What I now suspect is going on is that while deleting the snapshots > was quick, that probably kicks of a background thread which actually > does the heavy lifting. I noticed a btrfs-cleaner process that was in > an io wait state, which I presumed was the process in question. > However, now 40 minutes later, my unmount is still hung and the > btrfs-cleaner process is sleeping, so perhaps I am wrong.
The umount blocked by cleaner is known and I have now a patch ready to improve that http://thread.gmane.org/gmane.comp.file-systems.btrfs/23212 cleaner does not wait to do the background work for all deleted snapshots and is able to return in the middle of processing the current one when the fs si going down. There's another umount blocker, when a huge orphan file is being cleaned up, but from first look it also seems to be possible exit early if umount is detected. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
