linux-toradex.git/drivers/md, branch v3.2-rc5

md: raid5 crash during degradation

2011-12-09T03:26:11+00:00

NULL pointer access causes crash in raid5 module.

Signed-off-by: Adam Kwolek 
Signed-off-by: NeilBrown

md/raid5: never wait for bad-block acks on failed device.

2011-12-08T05:27:57+00:00

Once a device is failed we really want to completely ignore it.
It should go away soon anyway.

In particular the presence of bad blocks on it should not cause us to
block as we won't be trying to write there anyway.

So as soon as we can check if a device is Faulty, do so and pretend
that it is already gone if it is Faulty.

Signed-off-by: NeilBrown

md: ensure new badblocks are handled promptly.

2011-12-08T05:26:08+00:00

When we mark blocks as bad we need them to be acknowledged by the
metadata handler promptly.

For an in-kernel metadata handler that was already being done.  But
for an external metadata handler we need to alert it of the change by
sending a notification through the sysfs file.  This adds that
notification.

Signed-off-by: NeilBrown

md: bad blocks shouldn't cause a Blocked status on a Faulty device.

2011-12-08T05:22:48+00:00

Once a device is marked Faulty the badblocks - whether acknowledged or
not - become irrelevant.  So they shouldn't cause the device to be
marked as Blocked.

Without this patch, a process might write "-blocked" to clear the
Blocked status, but while that will correctly fail the device, it
won't remove the apparent 'blocked' status.

Signed-off-by: NeilBrown

md: take a reference to mddev during sysfs access.

2011-12-08T04:49:46+00:00

When we are accessing an mddev via sysfs we know that the
mddev cannot disappear because it has an embedded kobj which
is refcounted by sysfs.
And we also take the mddev_lock.
However this is not enough.

The final mddev_put could have been called and the
mddev_delayed_delete is waiting for sysfs to let go so it can destroy
the kobj and mddev.
In this state there are a lot of changes that should not be attempted.

To to guard against this we:
 - initialise mddev->all_mddevs in on last put so the state can be
   easily detected.
 - in md_attr_show and md_attr_store, check ->all_mddevs under
   all_mddevs_lock and mddev_get the mddev if it still appears to
   be active.

This means that if we get to sysfs as the mddev is being deleted we
will get -EBUSY.

rdev_attr_store and rdev_attr_show are similar but already have
sufficient protection.  They check that rdev->mddev still points to
mddev after taking mddev_lock.  As this is cleared  before delayed
removal which can only be requested under the mddev_lock, this
ensure the rdev and mddev are still alive.

Signed-off-by: NeilBrown

md: refine interpretation of "hold_active == UNTIL_IOCTL".

2011-12-08T04:49:12+00:00

We like md devices to disappear when they really are not needed.
However it is not possible to tell from the current state whether it
is needed or not.  We can only tell from recent history of changes.

In particular immediately after we create an md device it looks very
similar to immediately after we have finished with it.

So we always preserve a newly created md device until something
significant happens.  This state is stored in 'hold_active'.

The normal case is to keep it until an ioctl happens, as that will
normally either activate it, or explicitly de-activate it.  If it
doesn't then it was probably created by mistake and it is now time to
get rid of it.

We can also modify an array via sysfs (instead of via ioctl) and we
currently treat any change via sysfs like an ioctl as a sign that if
it now isn't more active, it should be destroyed.
However this is not appropriate as changes made via sysfs are more
gradual so we should look for a more definitive change.

So this patch only clears 'hold_active' from UNTIL_IOCTL to clear when
the array_state is changed via sysfs.  Other changes via sysfs
are ignored.

Signed-off-by: NeilBrown

md/lock: ensure updates to page_attrs are properly locked.

2011-11-22T23:18:52+00:00

Page attributes are set using __set_bit rather than set_bit as
it normally called under a spinlock so the extra atomicity is not
needed.

However there are two places where we might set or clear page
attributes without holding the spinlock.
So add the spinlock in those cases.

This might be the cause of occasional reports that bits a aren't
getting clear properly - theory is that BITMAP_PAGE_PENDING gets lost
when BITMAP_PAGE_NEEDWRITE is set or cleared.  This is an
inconvenience, not a threat to data safety.

Signed-off-by: NeilBrown

md/raid5: STRIPE_ACTIVE has lock semantics, add barriers

2011-11-08T05:22:06+00:00

All updates that occur under STRIPE_ACTIVE should be globally visible
when STRIPE_ACTIVE clears.  test_and_set_bit() implies a barrier, but
clear_bit() does not.

This is suitable for 3.1-stable.

Signed-off-by: Dan Williams 
Signed-off-by: NeilBrown 
Cc: stable@kernel.org

md/raid5: abort any pending parity operations when array fails.

2011-11-08T05:22:01+00:00

When the number of failed devices exceeds the allowed number
we must abort any active parity operations (checks or updates) as they
are no longer meaningful, and can lead to a BUG_ON in
handle_parity_checks6.

This bug was introduce by commit 6c0069c0ae9659e3a91b68eaed06a5c6c37f45c8
in 2.6.29.

Reported-by: Manish Katiyar 
Tested-by: Manish Katiyar 
Acked-by: Dan Williams 
Signed-off-by: NeilBrown 
Cc: stable@kernel.org

device-mapper: using EXPORT_SYBOL in dm-space-map-checker.c needs export.h

2011-11-07T18:29:10+00:00

Reported-by: Witold Baryluk 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Paul Gortmaker 
Signed-off-by: Linus Torvalds