You have been subscribed to a public bug by Eric Desrochers (slashd): [Impact]
* 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 #7 and later. - 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 ** Affects: util-linux (Ubuntu) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Ubuntu Xenial) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Ubuntu Bionic) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Ubuntu Disco) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Ubuntu Eoan) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Ubuntu Focal) Importance: Medium Assignee: Mauricio Faria de Oliveira (mfo) Status: In Progress ** Affects: util-linux (Debian) Importance: Unknown Status: Unknown ** Tags: patch sts sts-sponsor-mfo -- libblkid: no bcache UUID due to ambivalent detection of bcache and xfs_external_log for regular xfs in bcache backing device https://bugs.launchpad.net/bugs/1858802 You received this bug notification because you are a member of STS Sponsors, which is subscribed to the bug report. -- Mailing list: https://launchpad.net/~sts-sponsors Post to : [email protected] Unsubscribe : https://launchpad.net/~sts-sponsors More help : https://help.launchpad.net/ListHelp
