MegaBrutal schrieb am 01.12.2014 um 13:56: > Hi all, > > I've reported the bug I've previously posted about in "BTRFS messes up > snapshot LV with origin" in the Kernel Bug Tracker. > https://bugzilla.kernel.org/show_bug.cgi?id=89121 Hi MegaBrutal. If I understand your report correctly, I can give you another example where this bug is appearing. It is so bad that it leads to freezing the system and I'm quite sure it's the same thing. I was thinking about filing a bug but didn't have the time for that yet. Maybe you could add this case to your bug report as well.
The bug appears also when using mdadm RAID1 - when one of the drives is detached from the array then the OS discovers it and after a while (not directly, it takes several minutes) it appears under /proc/mounts: instead of /dev/md0p1 I see there /dev/sdb1. And usually after some hour or so (depending on system workload) the PC completely freezes. So discussion about the uniqueness of UUIDs or not, a crashing kernel is telling me that there is a serious bug. While in my case detaching was intentional, there are several real possibilities when a RAID1 disk can get detached and currently this leads to crashing the server when using BTRFS. That not what is intended when using RAID ;-). In my case I wanted to do something which was working perfectly all the years before with all other file systems - checking the file system of the root disk while the server is running. The procedure is simple: 1. detach one of the disks 2. do fsck on the disk device 3. mdadm --zero-superblock on the device so it gets completely rewritten 4. mdadm --add it to the array There were some surprises with BTRFS - if 2. is not done directly after 1. btrfsck refuses to check the disk as it is reported to be mounted by /proc/mounts. And while 2. or even after finishing it the system was freezing. If I got to get to 4. fast enough everything was OK, but again, that's not what I expect from a good operating system. Any objections? Konstantin -- 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
