** Description changed: - description/debdiffs to be provided. + [Impact] - upstream commit: - https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=d756af7d640c51ce8d1414607bd3f17eeecf2424 + * Users with an XFS filesystem on top of bcache + (this is seen on some ceph, cloud deployments) + might fail to reference the bcache device by + UUID or other udev properties. + + * The journal of the regular XFS filesystem in + the bcache device is incorrectly detected as + an XFS external log; so two superblocks are + detected (bcache and xfs_external_log). + + * Thus blkid fails with ambivalent superblocks + detected then doesn't provide the usual udev + properties (UUID, etc.) + + * The fix improves the probe function for XFS + external log so it detects it's regular XFS + and bails out. + + [Test Case] + + * See test steps detailed in comment #. + - Create an XFS filesystem with the journal/log + in the beginning of the bcache device (< 256K). + - Stop the bcache device. + - Run '$ blkid -o udev -p $BCACHE_BACKING_DEVICE'. + + $ sudo make-bcache -B $BACKING_DEV + $ sudo mkfs.xfs -d agsize=16m -l agnum=0 -f $BCACHE_DEV + $ echo 1 | sudo tee /sys/block/$(basename $BCACHE_DEV)/bcache/stop + $ sudo blkid -o udev -p $BACKING_DEV + + [Regression Potential] + + * The patch only changes the detection function + for XFS external log to be more general about + the sector where the magic of regular XFS may + be found (which is shifted inside the bcache.) + + * It still checks at sector zero (the only one + checked previously), so this behavior didn't + change. + + * Possible regressions are actual XFS external + log devices that are not anymore detected as + such. (Although that would probably indicate + a different bug in libblkid.) + + [Other Info] + * upstream commit: + https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=d756af7d640c51ce8d1414607bd3f17eeecf2424
** Bug watch added: Debian Bug tracker #948444 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=948444 ** Also affects: util-linux (Debian) via https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=948444 Importance: Unknown Status: Unknown -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1858802 Title: libblkid: no bcache UUID due to ambivalent detection of bcache and xfs_external_log for regular xfs in bcache backing device To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/1858802/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
