[ Upstream commit 042745ee53a0a7c1f5aff191a4a24213c6dcfb52 ]

Commit 3a0f9aaee028 ("dm raid: round region_size to power of two")
intended to make sure that the default region size is a power of two.
However, the logic in that commit is incorrect and sets the variable
region_size to 0 or 1, depending on whether min_region_size is a power
of two.

Fix this logic, using roundup_pow_of_two(), so that region_size is
properly rounded up to the next power of two.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 3a0f9aaee028 ("dm raid: round region_size to power of two")
Cc: stable@vger.kernel.org # v3.8+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

Commit 48cf06bc5f ("dm raid: add discard support for RAID levels 4, 5
and 6") did not properly handle missing metadata device(s).  A failing
read of the superblock causes the metadata and data devices to be
removed from the dev array in struct raid_set, setting references to
both devices to NULL.  configure_discard_support() nonetheless tries to
access the data dev unconditionally causing an oops.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The dm-raid superblock (struct dm_raid_superblock) is padded to 512
bytes and that size is being used to read it in from the metadata
device into one preallocated page.

Reading or writing this on a 512-byte sector device works fine but on
a 4096-byte sector device this fails.

Set the dm-raid superblock's size to the logical block size of the
metadata device, because IO at that size is guaranteed too work.  Also
add a size check to avoid silent partial metadata loss in case the
superblock should ever grow past the logical block size or PAGE_SIZE.

[includes pointer math fix from Dan Carpenter]
Reported-by: "Liuhua Wang" <lwang@suse.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

In case of RAID levels 4, 5 and 6 we have to verify each RAID members'
ability to zero data on discards to avoid stripe data corruption -- if
discard_zeroes_data is not set for each RAID member discard support must
be disabled.  But given the uncertainty of whether or not a RAID member
properly supports zeroing data on discard we require the user to
explicitly allow discard support on RAID levels 4, 5, and 6 by setting
a dm-raid module paramter, e.g.: dm-raid.devices_handle_discard_safely=Y
Otherwise, discards could cause data corruption on RAID4/5/6.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Discard support is not enabled for RAID levels 4, 5, and 6 at this time
due to concerns about unreliable discard_zeroes_data support on some
hardware.  Otherwise, discards could cause stripe data corruption
(classic example of bad apples spoiling the bunch).

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

MD:  Remember the last sync operation that was performed

This patch adds a field to the mddev structure to track the last
sync operation that was performed.  This is especially useful when
it comes to what is recorded in mismatch_cnt in sysfs.  If the
last operation was "data-check", then it reports the number of
descrepancies found by the user-initiated check.  If it was a
"repair" operation, then it is reporting the number of
descrepancies repaired.  etc.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: NeilBrown <neilb@suse.de>

This doesn't really need to be initialised, but it doesn't hurt,
silences the compiler, and as it is a counter it makes sense for it to
start at zero.

Signed-off-by: NeilBrown <neilb@suse.de>

DM RAID:  Fix raid_resume not reviving failed devices in all cases

When a device fails in a RAID array, it is marked as Faulty.  Later,
md_check_recovery is called which (through the call chain) calls
'hot_remove_disk' in order to have the personalities remove the device
from use in the array.

Sometimes, it is possible for the array to be suspended before the
personalities get their chance to perform 'hot_remove_disk'.  This is
normally not an issue.  If the array is deactivated, then the failed
device will be noticed when the array is reinstantiated.  If the
array is resumed and the disk is still missing, md_check_recovery will
be called upon resume and 'hot_remove_disk' will be called at that
time.  However, (for dm-raid) if the device has been restored,
a resume on the array would cause it to attempt to revive the device
by calling 'hot_add_disk'.  If 'hot_remove_disk' had not been called,
a situation is then created where the device is thought to concurrently
be the replacement and the device to be replaced.  Thus, the device
is first sync'ed with the rest of the array (because it is the replacement
device) and then marked Faulty and removed from the array (because
it is also the device being replaced).

The solution is to check and see if the device had properly been removed
before the array was suspended.  This is done by seeing whether the
device's 'raid_disk' field is -1 - a condition that implies that
'md_check_recovery -> remove_and_add_spares (where raid_disk is set to -1)
-> hot_remove_disk' has been called.  If 'raid_disk' is not -1, then
'hot_remove_disk' must be called to complete the removal of the previously
faulty device before it can be revived via 'hot_add_disk'.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

DM RAID:  Break-up untidy function

Clean-up excessive indentation by moving some code in raid_resume()
into its own function.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>