linux-stable.git/drivers/md, branch v3.2.71

md/raid1: fix test for 'was read error from last working device'.

2015-08-12T14:33:23+00:00

commit 34cab6f42003cb06f48f86a86652984dec338ae9 upstream.

When we get a read error from the last working device, we don't
try to repair it, and don't fail the device.  We simple report a
read error to the caller.

However the current test for 'is this the last working device' is
wrong.
When there is only one fully working device, it assumes that a
non-faulty device is that device.  However a spare which is rebuilding
would be non-faulty but so not the only working device.

So change the test from "!Faulty" to "In_sync".  If ->degraded says
there is only one fully working device and this device is in_sync,
this must be the one.

This bug has existed since we allowed read_balance to read from
a recovering spare in v3.0

Reported-and-tested-by: Alexander Lyakas 
Fixes: 76073054c95b ("md/raid1: clean up read_balance.")
Signed-off-by: NeilBrown 
Signed-off-by: Ben Hutchings

dm btree: silence lockdep lock inversion in dm_btree_del()

2015-08-12T14:33:20+00:00

commit 1c7518794a3647eb345d59ee52844e8a40405198 upstream.

Allocate memory using GFP_NOIO when deleting a btree.  dm_btree_del()
can be called via an ioctl and we don't want to recurse into the FS or
block layer.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm thin: allocate the cell_sort_array dynamically

2015-08-12T14:33:20+00:00

commit a822c83e47d97cdef38c4352e1ef62d9f46cfe98 upstream.

Given the pool's cell_sort_array holds 8192 pointers it triggers an
order 5 allocation via kmalloc.  This order 5 allocation is prone to
failure as system memory gets more fragmented over time.

Fix this by allocating the cell_sort_array using vmalloc.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.2: make a similar change in prison_{create,destroy}()]
Signed-off-by: Ben Hutchings

dm btree remove: fix bug in redistribute3

2015-08-12T14:33:19+00:00

commit 4c7e309340ff85072e96f529582d159002c36734 upstream.

redistribute3() shares entries out across 3 nodes.  Some entries were
being moved the wrong way, breaking the ordering.  This manifested as a
BUG() in dm-btree-remove.c:shift() when entries were removed from the
btree.

For additional context see:
https://www.redhat.com/archives/dm-devel/2015-May/msg00113.html

Signed-off-by: Dennis Yang 
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

md/raid5: don't record new size if resize_stripes fails.

2015-08-06T23:32:10+00:00

commit 6e9eac2dcee5e19f125967dd2be3e36558c42fff upstream.

If any memory allocation in resize_stripes fails we will return
-ENOMEM, but in some cases we update conf->pool_size anyway.

This means that if we try again, the allocations will be assumed
to be larger than they are, and badness results.

So only update pool_size if there is no error.

This bug was introduced in 2.6.17 and the patch is suitable for
-stable.

Fixes: ad01c9e3752f ("[PATCH] md: Allow stripes to be expanded in preparation for expanding an array")
Signed-off-by: NeilBrown 
Signed-off-by: Ben Hutchings

dm io: deal with wandering queue limits when handling REQ_DISCARD and REQ_WRITE_SAME

2015-05-09T22:16:25+00:00

commit e5db29806b99ce2b2640d2e4d4fcb983cea115c5 upstream.

Since it's possible for the discard and write same queue limits to
change while the upper level command is being sliced and diced, fix up
both of them (a) to reject IO if the special command is unsupported at
the start of the function and (b) read the limits once and let the
commands error out on their own if the status happens to change.

Signed-off-by: Darrick J. Wong 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.2: adjust context; drop the write_same handling]
Signed-off-by: Ben Hutchings

dm: hold suspend_lock while suspending device during device deletion

2015-05-09T22:16:25+00:00

commit ab7c7bb6f4ab95dbca96fcfc4463cd69843e3e24 upstream.

__dm_destroy() must take the suspend_lock so that its presuspend and
postsuspend calls do not race with an internal suspend.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm snapshot: fix a possible invalid memory access on unload

2015-05-09T22:16:18+00:00

commit 22aa66a3ee5b61e0f4a0bfeabcaa567861109ec3 upstream.

When the snapshot target is unloaded, snapshot_dtr() waits until
pending_exceptions_count drops to zero.  Then, it destroys the snapshot.
Therefore, the function that decrements pending_exceptions_count
should not touch the snapshot structure after the decrement.

pending_complete() calls free_pending_exception(), which decrements
pending_exceptions_count, and then it performs up_write(&s->lock) and it
calls retry_origin_bios() which dereferences  s->origin.  These two
memory accesses to the fields of the snapshot may touch the dm_snapshot
struture after it is freed.

This patch moves the call to free_pending_exception() to the end of
pending_complete(), so that the snapshot will not be destroyed while
pending_complete() is in progress.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm: fix a race condition in dm_get_md

2015-05-09T22:16:18+00:00

commit 2bec1f4a8832e74ebbe859f176d8a9cb20dd97f4 upstream.

The function dm_get_md finds a device mapper device with a given dev_t,
increases the reference count and returns the pointer.

dm_get_md calls dm_find_md, dm_find_md takes _minor_lock, finds the
device, tests that the device doesn't have DMF_DELETING or DMF_FREEING
flag, drops _minor_lock and returns pointer to the device. dm_get_md then
calls dm_get. dm_get calls BUG if the device has the DMF_FREEING flag,
otherwise it increments the reference count.

There is a possible race condition - after dm_find_md exits and before
dm_get is called, there are no locks held, so the device may disappear or
DMF_FREEING flag may be set, which results in BUG.

To fix this bug, we need to call dm_get while we hold _minor_lock. This
patch renames dm_find_md to dm_get_md and changes it so that it calls
dm_get while holding the lock.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm io: reject unsupported DISCARD requests with EOPNOTSUPP

2015-05-09T22:16:17+00:00

commit 37527b869207ad4c208b1e13967d69b8bba1fbf9 upstream.

I created a dm-raid1 device backed by a device that supports DISCARD
and another device that does NOT support DISCARD with the following
dm configuration:

 #  echo '0 2048 mirror core 1 512 2 /dev/sda 0 /dev/sdb 0' | dmsetup create moo
 # lsblk -D
 NAME         DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
 sda                 0        4K       1G         0
 `-moo (dm-0)        0        4K       1G         0
 sdb                 0        0B       0B         0
 `-moo (dm-0)        0        4K       1G         0

Notice that the mirror device /dev/mapper/moo advertises DISCARD
support even though one of the mirror halves doesn't.

If I issue a DISCARD request (via fstrim, mount -o discard, or ioctl
BLKDISCARD) through the mirror, kmirrord gets stuck in an infinite
loop in do_region() when it tries to issue a DISCARD request to sdb.
The problem is that when we call do_region() against sdb, num_sectors
is set to zero because q->limits.max_discard_sectors is zero.
Therefore, "remaining" never decreases and the loop never terminates.

To fix this: before entering the loop, check for the combination of
REQ_DISCARD and no discard and return -EOPNOTSUPP to avoid hanging up
the mirror device.

This bug was found by the unfortunate coincidence of pvmove and a
discard operation in the RHEL 6.5 kernel; upstream is also affected.

Signed-off-by: Darrick J. Wong 
Acked-by: "Martin K. Petersen" 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings