Re: [PULL] Re: bcache stability patches

[Jens Axboe <axboe@kernel.dk>]

On 12/29/2015 08:00 PM, Eric Wheeler wrote:
> Hi Jens and Kent,
>
> This affects many users, so please take a look when you have a moment:
>
> There is a growing bcache user community with a well-tested patchset that
> is necessary for production bcache use.  The diffstat is small and we all
> want someone to pull it in and get it into mainline.  This would serve
> many people if this can get pulled in upstream.
>
> More below:
>
> On Tue, 22 Dec 2015, Denis Bychkov wrote:
>> There is a set of bcache stability patches elevating bcache stability to
>> production level. As far as I know, there is no single reported and peer
>> confirmed bug that is not solved by this set. Unfortunately, for some
>> reason, Kent does not have enough time and/or energy to review them and
>> send them upstream. Let's come up with a solution that would allow to
>> review all these patches (some of them written by Ken himself, some of
>> them produced by the community), review them and hand them to the
>> maintainer who is willing to apply them upstream. Without that, bcache
>> is just another half-assed unstable and buggy cache layer. These patches
>> will allow people to start use bcache in production systems. Please find
>> the patch set attached. (The patches apply cleanly to 4.3 and 4.4 kernel
>> series).
>
> Hi Dennis,
>
> I'm maintaining a branch here that is ready to merge.  We have been
> testing this for about a year in production and works great.  All Cc's and
> authors are correct and it (should) have every stability patch below,
> possibly others too.  Please tell me if there are any patches missing:
>
> git pull https://github.com/ewheelerinc/linux.git bcache-patches-for-3.17
> (Yes, github for hosting only, I don't edit with their web interfaces.)
>
> Note that this branch still merges cleanly through v4.4-rc7 and as far
> back as 3.17-rc1 (maybe earlier).  Each patch provides Cc: stable@vger.kernel.org.
>
> It is ready to merge!  We just need Jens or Kent or someone to pull it in.
> Here is the diffstat and shortlog against v4.4-rc7:
>
>   drivers/md/bcache/btree.c     |  5 ++++-
>   drivers/md/bcache/super.c     | 16 ++++++++++++----
>   drivers/md/bcache/writeback.c | 37 ++++++++++++++++++++++++++++++-------
>   drivers/md/bcache/writeback.h |  3 ++-
>   4 files changed, 48 insertions(+), 13 deletions(-)
>
> Al Viro (1):
>        bcache: fix a leak in bch_cached_dev_run()
>
> Gabriel de Perthuis (1):
>        bcache: allows use of register in udev to avoid "device_busy" error.
>
> Kent Overstreet (2):
>        bcache: Add a cond_resched() call to gc
>        bcache: Change refill_dirty() to always scan entire disk if
> necessary
>
> Stefan Bader (1):
>        bcache: prevent crash on changing writeback_running
>
> Zheng Liu (3):
>        bcache: fix a livelock when we cause a huge number of cache misses
>        bcache: clear BCACHE_DEV_UNLINK_DONE flag when attaching a backing device
>        bcache: unregister reboot notifier if bcache fails to unregister device

Looking over these, most are really simple one-liners, and nothing 
sticks out as being overly complicated. Kent, do you have any plans to 
maintain the in-kernel bcache?

If I don't hear otherwise, I'll pull these in for 4.5.

-- 
Jens Axboe