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

MD: ignore discard request for hard disks of hybid raid1/raid10 array

2013-05-08T03:08:23+00:00

commit 32f9f570d04461a41bdcd5c1d93b41ebc5ce182a upstream.

In SSD/hard disk hybid storage, discard request should be ignored for hard
disk. We used to be doing this way, but the unplug path forgets it.

This is suitable for stable tree since v3.6.

Reported-and-tested-by: Markus 
Signed-off-by: Shaohua Li 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md: bad block list should default to disabled.

2013-05-08T03:08:23+00:00

commit 486adf72ccc0c235754923d47a2270c5dcb0c98b upstream.

Maintenance of a bad-block-list currently defaults to 'enabled'
and is then disabled when it cannot be supported.
This is backwards and causes problem for dm-raid which didn't know
to disable it.

So fix the defaults, and only enabled for v1.x metadata which
explicitly has bad blocks enabled.

The problem with dm-raid has been present since badblock support was
added in v3.1, so this patch is suitable for any -stable from 3.1
onwards.

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

md: raid1,10: Handle REQ_WRITE_SAME flag in write bios

2013-04-25T19:51:10+00:00

commit c8dc9c654794a765ca61baed07f84ed8aaa7ca8c upstream.

Set mddev queue's max_write_same_sectors to its chunk_sector value (before
disk_stack_limits merges the underlying disk limits.)  With that in place,
be sure to handle writes coming down from the block layer that have the
REQ_WRITE_SAME flag set.  That flag needs to be copied into any newly cloned
write bio.

Signed-off-by: Joe Lawrence 
Acked-by: "Martin K. Petersen" 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

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

dm verity: avoid deadlock

2013-03-28T19:17:48+00:00

commit 3b6b7813b198b578aa7e04e4047ddb8225c37b7f upstream.

A deadlock was found in the prefetch code in the dm verity map
function.  This patch fixes this by transferring the prefetch
to a worker thread and skipping it completely if kmalloc fails.

If generic_make_request is called recursively, it queues the I/O
request on the current->bio_list without making the I/O request
and returns. The routine making the recursive call cannot wait
for the I/O to complete.

The deadlock occurs when one thread grabs the bufio_client
mutex and waits for an I/O to complete but the I/O is queued
on another thread's current->bio_list and is waiting to get
the mutex held by the first thread.

The fix recognises that prefetching is not essential.  If memory
can be allocated, it queues the prefetch request to the worker thread,
but if not, it does nothing.

Signed-off-by: Paul Taysom 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Greg Kroah-Hartman

dm thin: fix discard corruption

2013-03-28T19:17:48+00:00

commit f046f89a99ccfd9408b94c653374ff3065c7edb3 upstream.

Fix a bug in dm_btree_remove that could leave leaf values with incorrect
reference counts.  The effect of this was that removal of a shared block
could result in the space maps thinking the block was no longer used.
More concretely, if you have a thin device and a snapshot of it, sending
a discard to a shared region of the thin could corrupt the snapshot.

Thinp uses a 2-level nested btree to store it's mappings.  This first
level is indexed by thin device, and the second level by logical
block.

Often when we're removing an entry in this mapping tree we need to
rebalance nodes, which can involve shadowing them, possibly creating a
copy if the block is shared.  If we do create a copy then children of
that node need to have their reference counts incremented.  In this
way reference counts percolate down the tree as shared trees diverge.

The rebalance functions were incrementing the children at the
appropriate time, but they were always assuming the children were
internal nodes.  This meant the leaf values (in our case packed
block/flags entries) were not being incremented.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Greg Kroah-Hartman

md/raid1,raid10: fix deadlock with freeze_array()

2013-03-14T18:26:22+00:00

commit ee0b0244030434cdda26777bfb98962447e080cd upstream.

When raid1/raid10 needs to fix a read error, it first drains
all pending requests by calling freeze_array().
This calls flush_pending_writes() if it needs to sleep,
but some writes may be pending in a per-process plug rather
than in the per-array request queue.

When raid1{,0}_unplug() moves the request from the per-process
plug to the per-array request queue (from which
flush_pending_writes() can flush them), it needs to wake up
freeze_array(), or freeze_array() will never flush them and so
it will block forever.

So add the requires wake_up() calls.

This bug was introduced by commit
   f54a9d0e59c4bea3db733921ca9147612a6f292c
for raid1 and a similar commit for RAID10, and so has been present
since linux-3.6.  As the bug causes a deadlock I believe this fix is
suitable for -stable.

Reported-by: Tregaron Bayly 
Tested-by: Tregaron Bayly 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md: raid0: fix error return from create_stripe_zones.

2013-03-14T18:26:22+00:00

commit 58ebb34c49fcfcaa029e4b1c1453d92583900f9a upstream.

Create_stripe_zones returns an error slightly differently to
raid0_run and to raid0_takeover_*.

The error returned used by the second was wrong and an error would
result in mddev->private being set to NULL and sooner or later a
crash.

So never return NULL, return ERR_PTR(err), not NULL from
create_stripe_zones.

This bug has been present since 2.6.35 so the fix is suitable
for any kernel since then.

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