I've run into a frustrating problem with a btrfs volume just now. I have a USB drive which has many partitions, two of which are luks encrypted, which can be unlocked as a single, multi-device btrfs volume. For some reason the drive logically disconnected at the USB protocol level, but not physically. Then it reconnected. This caused the mount point to be removed at the vfs layer, however I could not close the luks devices. When looking in /sys/fs/btrfs, I see a directory with the UUID of the offending volume, which shows the luks devices under the devices directory. So I presume the btrfs module is still holding references to the block devices, not allowing them to be closed. I know I can do a "dmsetup remove --force" to force closing the luks devices, but I doubt that will cause the btrfs module to release the offending block devices. So if I do that and then open the luks devices again and try to remount the btrfs volume, I'm guessing insanity will ensue. I can't unload/reload the btrfs module because the root fs among others are using it. Obviously, I can reboot, but that's a windows solution. Anyone have a solution to this issue? Is anyone looking into ways to prevent this from happening? I think this situation should be trivial to reproduce. Any help would be welcome, Glenn PS. I'm on a 4.10 kernel -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
