Pull md fixes from Neil Brown:
 "Two bugfixes for md

  both tagged for -stable"

* tag 'md/3.14-fixes' of git://neil.brown.name/md:
  md/raid5: Fix CPU hotplug callback registration
  md/raid1: restore ability for check and repair to fix read errors.

Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	register_cpu_notifier(&foobar_cpu_notifier);

	put_online_cpus();

This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).

Interestingly, the raid5 code can actually prevent double initialization and
hence can use the following simplified form of callback registration:

	register_cpu_notifier(&foobar_cpu_notifier);

	get_online_cpus();

	for_each_online_cpu(cpu)
		init_cpu(cpu);

	put_online_cpus();

A hotplug operation that occurs between registering the notifier and calling
get_online_cpus(), won't disrupt anything, because the code takes care to
perform the memory allocations only once.

So reorganize the code in raid5 this way to fix the deadlock with callback
registration.

Cc: linux-raid@vger.kernel.org
Cc: stable@vger.kernel.org (v2.6.32+)
Fixes: 36d1c6476be51101778882897b315bd928c8c7b5
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[Srivatsa: Fixed the unregister_cpu_notifier() deadlock, added the
free_scratch_buffer() helper to condense code further and wrote the changelog.]
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NeilBrown <neilb@suse.de>

commit 30bc9b53878a9921b02e3b5bc4283ac1c6de102a
    md/raid1: fix bio handling problems in process_checks()

Move the bio_reset() to a point before where BIO_UPTODATE is checked,
so that check now always report that the bio is uptodate, even if it is not.

This causes process_check() to sometimes treat read-errors as
successful matches so the good data isn't written out.

This patch preserves the flag until it is needed.

Bug was introduced in 3.11, but backported to 3.10-stable (as it fixed
an even worse bug).  So suitable for any -stable since 3.10.

Reported-and-tested-by: Michael Tokarev <mjt@tls.msk.ru>
Cc: stable@vger.kernel.org (3.10+)
Fixed: 30bc9b53878a9921b02e3b5bc4283ac1c6de102a
Signed-off-by: NeilBrown <neilb@suse.de>

Pull block IO driver changes from Jens Axboe:

 - bcache update from Kent Overstreet.

 - two bcache fixes from Nicholas Swenson.

 - cciss pci init error fix from Andrew.

 - underflow fix in the parallel IDE pg_write code from Dan Carpenter.
   I'm sure the 1 (or 0) users of that are now happy.

 - two PCI related fixes for sx8 from Jingoo Han.

 - floppy init fix for first block read from Jiri Kosina.

 - pktcdvd error return miss fix from Julia Lawall.

 - removal of IRQF_SHARED from the SEGA Dreamcast CD-ROM code from
   Michael Opdenacker.

 - comment typo fix for the loop driver from Olaf Hering.

 - potential oops fix for null_blk from Raghavendra K T.

 - two fixes from Sam Bradshaw (Micron) for the mtip32xx driver, fixing
   an OOM problem and a problem with handling security locked conditions

* 'for-3.14/drivers' of git://git.kernel.dk/linux-block: (47 commits)
  mg_disk: Spelling s/finised/finished/
  null_blk: Null pointer deference problem in alloc_page_buffers
  mtip32xx: Correctly handle security locked condition
  mtip32xx: Make SGL container per-command to eliminate high order dma allocation
  drivers/block/loop.c: fix comment typo in loop_config_discard
  drivers/block/cciss.c:cciss_init_one(): use proper errnos
  drivers/block/paride/pg.c: underflow bug in pg_write()
  drivers/block/sx8.c: remove unnecessary pci_set_drvdata()
  drivers/block/sx8.c: use module_pci_driver()
  floppy: bail out in open() if drive is not responding to block0 read
  bcache: Fix auxiliary search trees for key size > cacheline size
  bcache: Don't return -EINTR when insert finished
  bcache: Improve bucket_prio() calculation
  bcache: Add bch_bkey_equal_header()
  bcache: update bch_bkey_try_merge
  bcache: Move insert_fixup() to btree_keys_ops
  bcache: Convert sorting to btree_keys
  bcache: Convert debug code to btree_keys
  bcache: Convert btree_iter to struct btree_keys
  bcache: Refactor bset_tree sysfs stats
  ...

Pull core block IO changes from Jens Axboe:
 "The major piece in here is the immutable bio_ve series from Kent, the
  rest is fairly minor.  It was supposed to go in last round, but
  various issues pushed it to this release instead.  The pull request
  contains:

   - Various smaller blk-mq fixes from different folks.  Nothing major
     here, just minor fixes and cleanups.

   - Fix for a memory leak in the error path in the block ioctl code
     from Christian Engelmayer.

   - Header export fix from CaiZhiyong.

   - Finally the immutable biovec changes from Kent Overstreet.  This
     enables some nice future work on making arbitrarily sized bios
     possible, and splitting more efficient.  Related fixes to immutable
     bio_vecs:

        - dm-cache immutable fixup from Mike Snitzer.
        - btrfs immutable fixup from Muthu Kumar.

  - bio-integrity fix from Nic Bellinger, which is also going to stable"

* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
  xtensa: fixup simdisk driver to work with immutable bio_vecs
  block/blk-mq-cpu.c: use hotcpu_notifier()
  blk-mq: for_each_* macro correctness
  block: Fix memory leak in rw_copy_check_uvector() handling
  bio-integrity: Fix bio_integrity_verify segment start bug
  block: remove unrelated header files and export symbol
  blk-mq: uses page->list incorrectly
  blk-mq: use __smp_call_function_single directly
  btrfs: fix missing increment of bi_remaining
  Revert "block: Warn and free bio if bi_end_io is not set"
  block: Warn and free bio if bi_end_io is not set
  blk-mq: fix initializing request's start time
  block: blk-mq: don't export blk_mq_free_queue()
  block: blk-mq: make blk_sync_queue support mq
  block: blk-mq: support draining mq queue
  dm cache: increment bi_remaining when bi_end_io is restored
  block: fixup for generic bio chaining
  block: Really silence spurious compiler warnings
  block: Silence spurious compiler warnings
  block: Kill bio_pair_split()
  ...

Signed-off-by: Nicholas Swenson <nks@daterainc.com>

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

The BUG_ON at the end of __bch_btree_mark_key can be triggered due to
an integer overflow error:

BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, 13);
...
SET_GC_SECTORS_USED(g, min_t(unsigned,
	     GC_SECTORS_USED(g) + KEY_SIZE(k),
	     (1 << 14) - 1));
BUG_ON(!GC_SECTORS_USED(g));

In bcache.h, the SECTORS_USED bitfield is defined to be 13 bits wide.
While the SET_ code tries to ensure that the field doesn't overflow by
clamping it to (1<<14)-1 == 16383, this is incorrect because 16383
requires 14 bits.  Therefore, if GC_SECTORS_USED() + KEY_SIZE() =
8192, the SET_ statement tries to store 8192 into a 13-bit field.  In
a 13-bit field, 8192 becomes zero, thus triggering the BUG_ON.

Therefore, create a field width constant and a max value constant, and
use those to create the bitfield and check the inputs to
SET_GC_SECTORS_USED.  Arguably the BITMASK() template ought to have
BUG_ON checks for too-large values, but that's a separate patch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Pull md updates from Neil Brown:
 "All bug fixes, two tagged for -stable"

* tag 'md/3.14' of git://neil.brown.name/md:
  md/raid5: close recently introduced race in stripe_head management.
  md/raid5: fix long-standing problem with bitmap handling on write failure.
  md: check command validity early in md_ioctl().
  md: ensure metadata is writen after raid level change.
  md/raid10: avoid fullsync when not necessary.
  md: allow a partially recovered device to be hot-added to an array.
  md: Change handling of save_raid_disk and metadata update during recovery.