In my case, I was having trouble where in the
/export/<share>/ directory were listed various snapshots, but not the actual share data. I kept getting "resource busy" errors trying to delete snapshots, and after many reboots I was able to clear out all of my snapshots since I didn't need them anyway. I verified that I had no snapshots on any btrfs subvolume via commandline and listing them from
/mnt2/<share>/ as well.
However, when the exports fail to mount properly, the share directories are still there, and they still list old but empty snapshot directories in them. When the shares do mount properly, if I run
umount /export/<share> then the share directory is still there, and lists old (empty) snapshot directories. I cannot delete those directories directly via commandline (it spits at me with "operation not permitted").
Anyone have any ideas how to get rid of that stale crud in
Restarting the rockstor service via commandline hides that and gets the shares mounted again. So my shares are at least showing up via NFS again now. I've turned off all of my snapshot tasks for now until I can figure out what that crud is in
/export when shares aren't mounted.