linux-stable.git/drivers/md/md.c, branch v4.6

MD: make bio mergeable

2016-04-26T01:21:33+00:00

blk_queue_split marks bio unmergeable, which makes sense for normal bio.
But if dispatching the bio to underlayer disk, the blk_queue_split
checks are invalid, hence it's possible the bio becomes mergeable.

In the reported bug, this bug causes trim against raid0 performance slash
https://bugzilla.kernel.org/show_bug.cgi?id=117051

Reported-and-tested-by: Park Ju Hyung 
Fixes: 6ac45aeb6bca(block: avoid to merge splitted bio)
Cc: stable@vger.kernel.org (v4.3+)
Cc: Ming Lei 
Cc: Neil Brown 
Reviewed-by: Jens Axboe 
Signed-off-by: Shaohua Li

MD: add rdev reference for super write

2016-03-31T17:04:18+00:00

Xiao Ni reported below crash:
[26396.335146] BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8
[26396.342990] IP: [] super_written+0x20/0x80 [md_mod]
[26396.349449] PGD 0
[26396.351468] Oops: 0002 [#1] SMP
[26396.354898] Modules linked in: ext4 mbcache jbd2 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_td
[26396.408404] CPU: 5 PID: 3261 Comm: loop0 Not tainted 4.5.0 #1
[26396.414140] Hardware name: Dell Inc. PowerEdge R715/0G2DP3, BIOS 3.2.2 09/15/2014
[26396.421608] task: ffff8808339be680 ti: ffff8808365f4000 task.ti: ffff8808365f4000
[26396.429074] RIP: 0010:[]  [] super_written+0x20/0x80 [md_mod]
[26396.437952] RSP: 0018:ffff8808365f7c38  EFLAGS: 00010046
[26396.443252] RAX: ffffffffa0425ae0 RBX: ffff8804336a7900 RCX: ffffe8f9f7b41198
[26396.450371] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8804336a7900
[26396.457489] RBP: ffff8808365f7c50 R08: 0000000000000005 R09: 00001801e02ce3d7
[26396.464608] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
[26396.471728] R13: ffff8808338d9a00 R14: 0000000000000000 R15: ffff880833f9fe00
[26396.478849] FS:  00007f9e5066d740(0000) GS:ffff880237b40000(0000) knlGS:0000000000000000
[26396.486922] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[26396.492656] CR2: 00000000000002a8 CR3: 00000000019ea000 CR4: 00000000000006e0
[26396.499775] Stack:
[26396.501781]  ffff8804336a7900 0000000000000000 0000000000000000 ffff8808365f7c68
[26396.509199]  ffffffff81308cd0 ffff8804336a7900 ffff8808365f7ca8 ffffffff81310637
[26396.516618]  00000000a0233a00 ffff880833f9fe00 0000000000000000 ffff880833fb0000
[26396.524038] Call Trace:
[26396.526485]  [] bio_endio+0x40/0x60
[26396.531529]  [] blk_update_request+0x87/0x320
[26396.537439]  [] blk_mq_end_request+0x1a/0x70
[26396.543261]  [] blk_flush_complete_seq+0xd9/0x2a0
[26396.549517]  [] flush_end_io+0x15f/0x240
[26396.554993]  [] blk_mq_end_request+0x3a/0x70
[26396.560815]  [] __blk_mq_complete_request+0xb4/0xe0
[26396.567246]  [] blk_mq_complete_request+0x1c/0x20
[26396.573506]  [] loop_queue_work+0x6f/0x72c [loop]
[26396.579764]  [] ? __schedule+0x2b4/0x8f0
[26396.585242]  [] kthread_worker_fn+0x52/0x170
[26396.591065]  [] ? kthread_create_on_node+0x1a0/0x1a0
[26396.597582]  [] kthread+0xd8/0xf0
[26396.602453]  [] ? kthread_park+0x60/0x60
[26396.607929]  [] ret_from_fork+0x3f/0x70
[26396.613319]  [] ? kthread_park+0x60/0x60

md_super_write() and corresponding md_super_wait() generally are called
with reconfig_mutex locked, which prevents disk disappears. There is one
case this rule is broken. write_sb_page of bitmap.c doesn't hold the
mutex. next_active_rdev does increase rdev reference, but it decreases
the reference too early (eg, before IO finish). disk can disappear at
the window. We unconditionally increase rdev reference in
md_super_write() to avoid the race.

Reported-and-tested-by: Xiao Ni 
Reviewed-by: Neil Brown 
Signed-off-by: Shaohua Li

md: fix a trivial typo in comments

2016-03-31T17:04:18+00:00

Fix a trivial typo in md_ioctl().

Signed-off-by: Wei Fang 
Signed-off-by: Shaohua Li

MD: warn for potential deadlock

2016-02-26T17:44:57+00:00

The personality thread shouldn't call mddev_suspend(). Because
mddev_suspend() will for all IO finish, but IO is handled in personality
thread, so this could cause deadlock. To trigger this early, add a
warning if mddev_suspend() is called from personality thread.

Suggested-by: NeilBrown 
Cc: Artur Paszkiewicz 
Signed-off-by: Shaohua Li

md: Drop sending a change uevent when stopping

2016-02-26T17:44:56+00:00

When stopping an MD device, then its device node /dev/mdX may still
exist afterwards or it is recreated by udev. The next open() call
can lead to creation of an inoperable MD device. The reason for
this is that a change event (KOBJ_CHANGE) is sent to udev which
races against the remove event (KOBJ_REMOVE) from md_free().
So drop sending the change event.

A change is likely also required in mdadm as many versions send the
change event to udev as well.

Neil mentioned the change event is a workaround for old kernel
Commit: 934d9c23b4c7 ("md: destroy partitions and notify udev when md array is stopped.")
new mdadm can handle device remove now, so this isn't required any more.

Cc: NeilBrown 
Cc: Hannes Reinecke 
Cc: Jes Sorensen 
Signed-off-by: Sebastian Parschauer 
Signed-off-by: Shaohua Li

Merge tag 'md/4.5' of git://neil.brown.name/md

2016-01-15T20:28:00+00:00

Pull md updates from Neil Brown:
 "Mostly clustered-raid1 and raid5 journal updates.  one Y2038 fix and
  other minor stuff.

  One patch removes me from the MAINTAINERS file and adds a record of my
  md maintainership to Credits"

Many thanks to Neil, who has been around for a _looong_ time.

* tag 'md/4.5' of git://neil.brown.name/md: (26 commits)
  md/raid: only permit hot-add of compatible integrity profiles
  Remove myself as MD Maintainer, and add to Credits.
  raid5-cache: handle journal hotadd in quiesce
  MD: add journal with array suspended
  md: set MD_HAS_JOURNAL in correct places
  md: Remove 'ready' field from mddev.
  md: remove unnecesary md_new_event_inintr
  raid5: allow r5l_io_unit allocations to fail
  raid5-cache: use a mempool for the metadata block
  raid5-cache: use a bio_set
  raid5-cache: add journal hot add/remove support
  drivers: md: use ktime_get_real_seconds()
  md: avoid warning for 32-bit sector_t
  raid5-cache: free meta_page earlier
  raid5-cache: simplify r5l_move_io_unit_list
  md: update comment for md_allow_write
  md-cluster: update comments for MD_CLUSTER_SEND_LOCKED_ALREADY
  md-cluster: Protect communication with mutexes
  md-cluster: Defer MD reloading to mddev->thread
  md-cluster: update the documentation
  ...

Merge tag 'libnvdimm-for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2016-01-14T03:15:14+00:00

Pull libnvdimm updates from Dan Williams:
 "The bulk of this has appeared in -next and independently received a
  build success notification from the kbuild robot.  The 'for-4.5/block-
  dax' topic branch was rebased over the weekend to drop the "block
  device end-of-life" rework that Al would like to see re-implemented
  with a notifier, and to address bug reports against the badblocks
  integration.

  There is pending feedback against "libnvdimm: Add a poison list and
  export badblocks" received last week.  Linda identified some localized
  fixups that we will handle incrementally.

  Summary:

   - Media error handling: The 'badblocks' implementation that
     originated in md-raid is up-levelled to a generic capability of a
     block device.  This initial implementation is limited to being
     consulted in the pmem block-i/o path.  Later, 'badblocks' will be
     consulted when creating dax mappings.

   - Raw block device dax: For virtualization and other cases that want
     large contiguous mappings of persistent memory, add the capability
     to dax-mmap a block device directly.

   - Increased /dev/mem restrictions: Add an option to treat all
     io-memory as IORESOURCE_EXCLUSIVE, i.e. disable /dev/mem access
     while a driver is actively using an address range.  This behavior
     is controlled via the new CONFIG_IO_STRICT_DEVMEM option and can be
     overridden by the existing "iomem=relaxed" kernel command line
     option.

   - Miscellaneous fixes include a 'pfn'-device huge page alignment fix,
     block device shutdown crash fix, and other small libnvdimm fixes"

* tag 'libnvdimm-for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (32 commits)
  block: kill disk_{check|set|clear|alloc}_badblocks
  libnvdimm, pmem: nvdimm_read_bytes() badblocks support
  pmem, dax: disable dax in the presence of bad blocks
  pmem: fail io-requests to known bad blocks
  libnvdimm: convert to statically allocated badblocks
  libnvdimm: don't fail init for full badblocks list
  block, badblocks: introduce devm_init_badblocks
  block: clarify badblocks lifetime
  badblocks: rename badblocks_free to badblocks_exit
  libnvdimm, pmem: move definition of nvdimm_namespace_add_poison to nd.h
  libnvdimm: Add a poison list and export badblocks
  nfit_test: Enable DSMs for all test NFITs
  md: convert to use the generic badblocks code
  block: Add badblock management for gendisks
  badblocks: Add core badblock management code
  block: fix del_gendisk() vs blkdev_ioctl crash
  block: enable dax for raw block devices
  block: introduce bdev_file_inode()
  restrict /dev/mem to idle io memory ranges
  arch: consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug
  ...

md/raid: only permit hot-add of compatible integrity profiles

2016-01-14T00:49:57+00:00

It is not safe for an integrity profile to be changed while i/o is
in-flight in the queue.  Prevent adding new disks or otherwise online
spares to an array if the device has an incompatible integrity profile.

The original change to the blk_integrity_unregister implementation in
md, commmit c7bfced9a671 "md: suspend i/o during runtime
blk_integrity_unregister" introduced an immediate hang regression.

This policy of disallowing changes the integrity profile once one has
been established is shared with DM.

Here is an abbreviated log from a test run that:
1/ Creates a degraded raid1 with an integrity-enabled device (pmem0s) [   59.076127]
2/ Tries to add an integrity-disabled device (pmem1m) [   90.489209]
3/ Retries with an integrity-enabled device (pmem1s) [  205.671277]

[   59.076127] md/raid1:md0: active with 1 out of 2 mirrors
[   59.078302] md: data integrity enabled on md0
[..]
[   90.489209] md0: incompatible integrity profile for pmem1m
[..]
[  205.671277] md: super_written gets error=-5
[  205.677386] md/raid1:md0: Disk failure on pmem1m, disabling device.
[  205.677386] md/raid1:md0: Operation continuing on 1 devices.
[  205.683037] RAID1 conf printout:
[  205.684699]  --- wd:1 rd:2
[  205.685972]  disk 0, wo:0, o:1, dev:pmem0s
[  205.687562]  disk 1, wo:1, o:1, dev:pmem1s
[  205.691717] md: recovery of RAID array md0

Fixes: c7bfced9a671 ("md: suspend i/o during runtime blk_integrity_unregister")
Cc: 
Cc: Mike Snitzer 
Reported-by: NeilBrown 
Signed-off-by: Dan Williams 
Signed-off-by: NeilBrown

MD: add journal with array suspended

2016-01-14T00:49:43+00:00

Hot add journal disk in recovery thread context brings a lot of trouble
as IO could be running. Unlike spare disk hot add, adding journal disk
with array suspended makes more sense and implmentation is much easier.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown

md: set MD_HAS_JOURNAL in correct places

2016-01-14T00:49:43+00:00

Set MD_HAS_JOURNAL when a array is loaded or journal is initialized.
This is to avoid the flags set too early in journal disk hotadd.

Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown