** No longer affects: bcache-tools (Ubuntu) ** Changed in: bcache-tools (Ubuntu Bionic) Status: In Progress => Invalid
** Changed in: bcache-tools (Ubuntu Artful) Status: Confirmed => Invalid ** Changed in: bcache-tools (Ubuntu Xenial) Status: Confirmed => Invalid ** Changed in: bcache-tools (Ubuntu Trusty) Status: Confirmed => Invalid ** Changed in: bcache-tools (Ubuntu Bionic) Assignee: Ryan Harper (raharper) => (unassigned) ** Also affects: curtin (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of नेपाली भाषा समायोजकहरुको समूह, which is subscribed to Xenial. Matching subscriptions: Ubuntu 16.04 Bugs https://bugs.launchpad.net/bugs/1728742 Title: curtin dname for bcache uses unstable devname instead of UUID Status in bcache-tools: New Status in curtin: Fix Committed Status in curtin package in Ubuntu: New Status in bcache-tools source package in Trusty: Invalid Status in curtin source package in Trusty: New Status in bcache-tools source package in Xenial: Invalid Status in curtin source package in Xenial: New Status in bcache-tools source package in Artful: Invalid Status in curtin source package in Artful: New Status in bcache-tools source package in Bionic: Invalid Status in curtin source package in Bionic: New Status in bcache-tools package in Debian: Confirmed Bug description: [Impact] * Current users of bcache devices may encounter unreliable device numbering as the Linux kernel does not guarantee that bcache minor numbers are assigned to the same devices at each boot. Users who may have used /dev/bcacheN in paths to a specific device could possible be pointing to a different dataset altogether. bcache udev rules do provide some mechanism to generate persistent symlinks in /dev/bcache/by-uuid or /dev/bcache/by-label which is based on superblock data on the underlying device. However, the Linux kernel does not always generate an kernel uevent to trigger the udev rules to create the symlink. * The fix adds a udev program which will read bcache superblock of slave devices and extract the UUID and LABEL, exporting them to udev for use in the bcache rule files. * This is affected in upstream bcache-tools, the owning package of the udev rules. This affects all releases of bcache-tools as the rules rely upon the kernel to trigger these events, though that is not a requirement to resolve the lack of persistent links. [Test Case] * Launch and Ubuntu Cloud Image with 3 unused disks - apt install bcache-tools tree - make-bcache -C /dev/vdb - make-bcache -B /dev/vdc - make-bcache -B /dev/vdd - echo "vdc" > /sys/class/block/bcache0/bcache/label - echo "vdd" > /sys/class/block/bcache1/bcache/label - reboot - Run this test: #!/bin/bash FAIL=0 [ ! -d /dev/bcache ] && { echo "FAIL: /dev/bcache is not a directory"; exit 1 } for label in /dev/bcache/by-label/*; do LABEL_TARGET="$(ls -1 /sys/class/block/`basename $label`/holders/)" DEVNAME=`readlink -f $label`; KNAME="${DEVNAME#*/dev/}" if [ "$LABEL_TARGET" != "$KNAME" ]; then echo "FAIL: label points to $LABEL_TARGET but symlink points to $DEVNAME"; FAIL=1 fi; done if [ "$FAIL" == "0" ]; then echo "PASS"; exit 0 fi exit 1 [Regression Potential] * As bcache minor numbers and these symlinks have been unreliable in the past there may be code that makes assumptions about /dev/bcache* expanded only to the block devices, versus /dev/bcache which is a directory. [Original Description] Bcache device names like /dev/bcache0 are unstable. Bcache does not use any predictable ordering when assembling bcache devices, so on systems with multiple bcache devices, a symlink to /dev/bcache0 may end up pointing do a different device. the bcache dname symlink should point to the /dev/bcache/by- uuid/<UUID> which matches the backing device UUID that's set at creation time. Related bugs: * bug 1729145: [kernel] /dev/bcache/by-uuid links not created after reboot To manage notifications about this bug go to: https://bugs.launchpad.net/bcache-tools/+bug/1728742/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~group.of.nepali.translators Post to : group.of.nepali.translators@lists.launchpad.net Unsubscribe : https://launchpad.net/~group.of.nepali.translators More help : https://help.launchpad.net/ListHelp