linux-stable.git/drivers/md/raid5.c, branch linux-3.8.y

md/raid5: ensure sync and DISCARD don't happen at the same time.

2013-03-28T19:18:01+00:00

commit f8dfcffd0472a0f353f34a567ad3f53568914d04 upstream.

A number of problems can occur due to races between
resync/recovery and discard.

- if sync_request calls handle_stripe() while a discard is
  happening on the stripe, it might call handle_stripe_clean_event
  before all of the individual discard requests have completed
  (so some devices are still locked, but not all).
  Since commit ca64cae96037de16e4af92678814f5d4bf0c1c65
     md/raid5: Make sure we clear R5_Discard when discard is finished.
  this will cause R5_Discard to be cleared for the parity device,
  so handle_stripe_clean_event() will not be called when the other
  devices do become unlocked, so their ->written will not be cleared.
  This ultimately leads to a WARN_ON in init_stripe and a lock-up.

- If handle_stripe_clean_event() does clear R5_UPTODATE at an awkward
  time for resync, it can lead to s->uptodate being less than disks
  in handle_parity_checks5(), which triggers a BUG (because it is
  one).

So:
 - keep R5_Discard on the parity device until all other devices have
   completed their discard request
 - make sure we don't try to have a 'discard' and a 'sync' action at
   the same time.
   This involves a new stripe flag to we know when a 'discard' is
   happening, and the use of R5_Overlap on the parity disk so when a
   discard is wanted while a sync is active, so we know to wake up
   the discard at the appropriate time.

Discard support for RAID5 was added in 3.7, so this is suitable for
any -stable kernel since 3.7.

Reported-by: Jes Sorensen 
Tested-by: Jes Sorensen 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

MD RAID5: Avoid accessing gendisk or queue structs when not available

2013-03-28T19:18:01+00:00

commit e3620a3ad52609f64a2402e4b59300afb4b83b77 upstream.

MD RAID5:  Fix kernel oops when RAID4/5/6 is used via device-mapper

Commit a9add5d (v3.8-rc1) added blktrace calls to the RAID4/5/6 driver.
However, when device-mapper is used to create RAID4/5/6 arrays, the
mddev->gendisk and mddev->queue fields are not setup.  Therefore, calling
things like trace_block_bio_remap will cause a kernel oops.  This patch
conditionalizes those calls on whether the proper fields exist to make
the calls.  (Device-mapper will call trace_block_bio_remap on its own.)

This patch is suitable for the 3.8.y stable kernel.

Signed-off-by: Jonathan Brassow 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md/raid5: schedule_construction should abort if nothing to do.

2013-03-28T19:18:01+00:00

commit ce7d363aaf1e28be8406a2976220944ca487e8ca upstream.

Since commit 1ed850f356a0a422013846b5291acff08815008b
    md/raid5: make sure to_read and to_write never go negative.

It has been possible for handle_stripe_dirtying to be called
when there isn't actually any work to do.
It then calls schedule_reconstruction() which will set R5_LOCKED
on the parity block(s) even when nothing else is happening.
This then causes problems in do_release_stripe().

So add checks to schedule_reconstruction() so that if it doesn't
find anything to do, it just aborts.

This bug was introduced in v3.7, so the patch is suitable
for -stable kernels since then.

Reported-by: majianpeng 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'md-3.8' of git://neil.brown.name/md

2012-12-18T17:32:44+00:00

Pull md update from Neil Brown:
 "Mostly just little fixes.  Probably biggest part is AVX accelerated
  RAID6 calculations."

* tag 'md-3.8' of git://neil.brown.name/md:
  md/raid5: add blktrace calls
  md/raid5: use async_tx_quiesce() instead of open-coding it.
  md: Use ->curr_resync as last completed request when cleanly aborting resync.
  lib/raid6: build proper files on corresponding arch
  lib/raid6: Add AVX2 optimized gen_syndrome functions
  lib/raid6: Add AVX2 optimized recovery functions
  md: Update checkpoint of resync/recovery based on time.
  md:Add place to update ->recovery_cp.
  md.c: re-indent various 'switch' statements.
  md: close race between removing and adding a device.
  md: removed unused variable in calc_sb_1_csm.

md/raid5: add blktrace calls

2012-12-17T23:22:21+00:00

This makes it easier to trace what raid5 is doing.

Signed-off-by: NeilBrown

Merge branch 'for-3.8/drivers' of git://git.kernel.dk/linux-block

2012-12-17T21:39:11+00:00

Pull block driver update from Jens Axboe:
 "Now that the core bits are in, here are the driver bits for 3.8.  The
  branch contains:

   - A huge pile of drbd bits that were dumped from the 3.7 merge
     window.  Following that, it was both made perfectly clear that
     there is going to be no more over-the-wall pulls and how the
     situation on individual pulls can be improved.

   - A few cleanups from Akinobu Mita for drbd and cciss.

   - Queue improvement for loop from Lukas.  This grew into adding a
     generic interface for waiting/checking an even with a specific
     lock, allowing this to be pulled out of md and now loop and drbd is
     also using it.

   - A few fixes for xen back/front block driver from Roger Pau Monne.

   - Partition improvements from Stephen Warren, allowing partiion UUID
     to be used as an identifier."

* 'for-3.8/drivers' of git://git.kernel.dk/linux-block: (609 commits)
  drbd: update Kconfig to match current dependencies
  drbd: Fix drbdsetup wait-connect, wait-sync etc... commands
  drbd: close race between drbd_set_role and drbd_connect
  drbd: respect no-md-barriers setting also when changed online via disk-options
  drbd: Remove obsolete check
  drbd: fixup after wait_even_lock_irq() addition to generic code
  loop: Limit the number of requests in the bio list
  wait: add wait_event_lock_irq() interface
  xen-blkfront: free allocated page
  xen-blkback: move free persistent grants code
  block: partition: msdos: provide UUIDs for partitions
  init: reduce PARTUUID min length to 1 from 36
  block: store partition_meta_info.uuid as a string
  cciss: use check_signature()
  cciss: cleanup bitops usage
  drbd: use copy_highpage
  drbd: if the replication link breaks during handshake, keep retrying
  drbd: check return of kmalloc in receive_uuids
  drbd: Broadcast sync progress no more often than once per second
  drbd: don't try to clear bits once the disk has failed
  ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2012-12-13T20:00:02+00:00

Pull trivial branch from Jiri Kosina:
 "Usual stuff -- comment/printk typo fixes, documentation updates, dead
  code elimination."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  HOWTO: fix double words typo
  x86 mtrr: fix comment typo in mtrr_bp_init
  propagate name change to comments in kernel source
  doc: Update the name of profiling based on sysfs
  treewide: Fix typos in various drivers
  treewide: Fix typos in various Kconfig
  wireless: mwifiex: Fix typo in wireless/mwifiex driver
  messages: i2o: Fix typo in messages/i2o
  scripts/kernel-doc: check that non-void fcts describe their return value
  Kernel-doc: Convention: Use a "Return" section to describe return values
  radeon: Fix typo and copy/paste error in comments
  doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c
  various: Fix spelling of "asynchronous" in comments.
  Fix misspellings of "whether" in comments.
  eisa: Fix spelling of "asynchronous".
  various: Fix spelling of "registered" in comments.
  doc: fix quite a few typos within Documentation
  target: iscsi: fix comment typos in target/iscsi drivers
  treewide: fix typo of "suport" in various comments and Kconfig
  treewide: fix typo of "suppport" in various comments
  ...

md/raid5: use async_tx_quiesce() instead of open-coding it.

2012-12-13T08:52:32+00:00

handle_stripe_expansion contains:

        if (tx) {
                async_tx_ack(tx);
                dma_wait_for_async_tx(tx);
        }

which is very similar to the body of async_tx_quiesce(),
except that the later handles an error from dma_wait_for_async_tx()
(admittedly by panicing, but that decision belongs in the dma
code, not the md code).

So just us async_tx_quiesce().

Acked-by: Dan Williams 
Reported-by: Bartlomiej Zolnierkiewicz 
Signed-off-by: NeilBrown

wait: add wait_event_lock_irq() interface

2012-11-30T10:47:57+00:00

New wait_event{_interruptible}_lock_irq{_cmd} macros added. This commit
moves the private wait_event_lock_irq() macro from MD to regular wait
includes, introduces new macro wait_event_lock_irq_cmd() instead of using
the old method with omitting cmd parameter which is ugly and makes a use
of new macros in the MD. It also introduces the _interruptible_ variant.

The use of new interface is when one have a special lock to protect data
structures used in the condition, or one also needs to invoke "cmd"
before putting it to sleep.

All new macros are expected to be called with the lock taken. The lock
is released before sleep and is reacquired afterwards. We will leave the
macro with the lock held.

Note to DM: IMO this should also fix theoretical race on waitqueue while
using simultaneously wait_event_lock_irq() and wait_event() because of
lack of locking around current state setting and wait queue removal.

Signed-off-by: Lukas Czerner 
Cc: Neil Brown 
Cc: David Howells 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Jens Axboe

md/raid5: Make sure we clear R5_Discard when discard is finished.

2012-11-21T22:14:13+00:00

commit 9e44476851e91c86c98eb92b9bc27fb801f89072
    MD: raid5 avoid unnecessary zero page for trim

change raid5 to clear R5_Discard when the complete request is
handled rather than when submitting the per-device discard request.
However it did not clear R5_Discard for the parity device.

This means that if the stripe_head was reused before it expired from
the cache, the setting would be wrong and a hang would result.

Also if the R5_Uptodate bit happens to be set, R5_Discard again
won't be cleared.  But R5_Uptodate really should be clear at this point.

So make sure R5_Discard is cleared in all cases, and clear
R5_Uptodate when a 'discard' completes.

Signed-off-by: NeilBrown