[SRU][Zesty][PATCH 0/2] UBUNTU: SAUCE: (no-up) Fixes for LP:1729145

Joseph Salisbury joseph.salisbury at canonical.com
Thu Dec 7 19:41:11 UTC 2017

BugLink: http://bugs.launchpad.net/bugs/1729145 
== SRU Justification ==
This bug is preventing /dev/bcache/by-uuid links from beingcreated after reboot.
It appears that since the initramfs loads the bcache module which probes and 
finds all of the cache devices and backing devices then once the rootfs is
mounted and udev gets to run, the bcache kernel module does not emit the
CACHED_UUID value into the environment if the underlying devices are already registered.     

With this patch, instead of just failing with "device already registered"
the kernel emits another uevent with CACHED_UUID which would be processed
another time to set up a symlink.

This patch is not yet upstream, but we will submit it there as well.  However,
requesting this a SAUCE patch until it lands upstream.

This patch has also been submitted for X, A and B.  However, Zesty also 
needs mainlin commit 4b758df21e as a prereq.  Commit 4b758df21e was cc'd to 
upstream stable.  However, 4.10 is EOL upstream, so Zesty never got it.    

== Fix ==
Patch from Ryan Harper <ryan.harper at canonical.com>:
bcache: decouple emitting a cached_dev CHANGE uevent

Also the following commit as a prereq:
4b758df21ee7 ("bcache: Fix leak of bdev reference")

== Regression Potential ==
There is some risk of regression, since this is new code.   However, it is
limited to the bcache.

== Test Case ==
A test kernel was built with these patches and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.

Jan Kara (1):
  bcache: Fix leak of bdev reference

Ryan Harper (1):
  bcache: decouple emitting a cached_dev CHANGE uevent

 drivers/md/bcache/bcache.h |  1 +
 drivers/md/bcache/super.c  | 55 +++++++++++++++++++++++++++++++++++++---------
 2 files changed, 46 insertions(+), 10 deletions(-)


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