[Nbd] [PATCH v2 0/7] block: reread partitions changes and fix for loop
- To: Jens Axboe <axboe@...161...>, linux-kernel@...25..., Christoph Hellwig <hch@...1270...>, Tejun Heo <tj@...1285...>
- Cc: nbd-general@lists.sourceforge.net, linux-s390@...25..., Peter Zijlstra <peterz@...1270...>, Stefan Haberland <stefan.haberland@...1296...>, Sebastian Ott <sebott@...1294...>, Jarod Wilson <jarod@...696...>, Fabian Frederick <fabf@...1980...>, Alexander Viro <viro@...1300...>, David Herrmann <dh.herrmann@...17...>, Andrew Morton <akpm@...133...>
- Subject: [Nbd] [PATCH v2 0/7] block: reread partitions changes and fix for loop
- From: Ming Lei <ming.lei@...1301...>
- Date: Sat, 11 Apr 2015 19:30:06 +0800
- Message-id: <1428751813-25199-1-git-send-email-ming.lei@...1301...>
Hi Guys,
Recently there are several reports about loop partition scanning
failure[1][2].
For loop, the root cause is one ABBA and one AA lock dependency
issue, and the two are fixed by patch 2 and patch 3 each.
Another reason is from the trylock in blkdev_reread_part(), which
may cause partition scanning failure too sometimes when another task
is holding the bd_mutex. In the discussion[1], both Tejun and Christoph
suggests to replace the trylock with mutex_lock in blkdev_reread_part(),
also Christoph suggests to export blkdev_reread_part.
Following the discussion, this patchset exports blkdev_reread_part(), and
introduces __blkdev_reread_part() for fixing loop's AA lock issue.
Then ioctl_by_bdev(BLKRRPART) in loop, nbd and dasd is replaced with
blkdev_reread_part(). In the last patch, trylock in blkdev_reread_part()
is replaced with mutex_lock, and some analysis is provided about the conversion.
V2:
- only print debug message in case of error (7/7)
- add tested-by, acked-by
V1:
- introduce __blkdev_reread_part(), and use lockdep_assert_held()(1/7)
- replace lo_open_mutex with atomic reference count, plus freezing queue(2/7)
- add comment about detecting release path(3/7)
- remove dead code in dasd(7/7)
block/ioctl.c | 37 +++++++++++++++++++++++++----
drivers/block/loop.c | 49 +++++++++++++++++++++++++++++----------
drivers/block/loop.h | 2 +-
drivers/block/nbd.c | 2 +-
drivers/s390/block/dasd_genhd.c | 19 ++++-----------
include/linux/fs.h | 3 +++
6 files changed, 79 insertions(+), 33 deletions(-)
[1], https://lkml.org/lkml/2015/1/26/137
[2], https://lkml.org/lkml/2015/3/31/888
Thanks,
Ming Lei
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