linux-stable.git/drivers/md, branch v3.14.13

dm: allocate a special workqueue for deferred device removal

2014-07-17T23:21:05+00:00

commit acfe0ad74d2e1bfc81d1d7bf5e15b043985d3650 upstream.

The commit 2c140a246dc ("dm: allow remove to be deferred") introduced a
deferred removal feature for the device mapper.  When this feature is
used (by passing a flag DM_DEFERRED_REMOVE to DM_DEV_REMOVE_CMD ioctl)
and the user tries to remove a device that is currently in use, the
device will be removed automatically in the future when the last user
closes it.

Device mapper used the system workqueue to perform deferred removals.
However, some targets (dm-raid1, dm-mpath, dm-stripe) flush work items
scheduled for the system workqueue from their destructor.  If the
destructor itself is called from the system workqueue during deferred
removal, it introduces a possible deadlock - the workqueue tries to flush
itself.

Fix this possible deadlock by introducing a new workqueue for deferred
removals.  We allocate just one workqueue for all dm targets.  The
ability of dm targets to process IOs isn't dependent on deferred removal
of unused targets, so a deadlock due to shared workqueue isn't possible.

Also, cleanup local_init() to eliminate potential for returning success
on failure.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Dan Carpenter 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm io: fix a race condition in the wake up code for sync_io

2014-07-17T23:21:05+00:00

commit 10f1d5d111e8aed46a0f1179faf9a3cf422f689e upstream.

There's a race condition between the atomic_dec_and_test(&io->count)
in dec_count() and the waking of the sync_io() thread.  If the thread
is spuriously woken immediately after the decrement it may exit,
making the on stack io struct invalid, yet the dec_count could still
be using it.

Fix this race by using a completion in sync_io() and dec_count().

Reported-by: Minfei Huang 
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Acked-by: Mikulas Patocka 
Signed-off-by: Greg Kroah-Hartman

md: flush writes before starting a recovery.

2014-07-09T18:18:28+00:00

commit 133d4527eab8d199a62eee6bd433f0776842df2e upstream.

When we write to a degraded array which has a bitmap, we
make sure the relevant bit in the bitmap remains set when
the write completes (so a 're-add' can quickly rebuilt a
temporarily-missing device).

If, immediately after such a write starts, we incorporate a spare,
commence recovery, and skip over the region where the write is
happening (because the 'needs recovery' flag isn't set yet),
then that write will not get to the new device.

Once the recovery finishes the new device will be trusted, but will
have incorrect data, leading to possible corruption.

We cannot set the 'needs recovery' flag when we start the write as we
do not know easily if the write will be "degraded" or not.  That
depends on details of the particular raid level and particular write
request.

This patch fixes a corruption issue of long standing and so it
suitable for any -stable kernel.  It applied correctly to 3.0 at
least and will minor editing to earlier kernels.

Reported-by: Bill 
Tested-by: Bill 
Link: http://lkml.kernel.org/r/53A518BB.60709@sbcglobal.net
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

dm thin: update discard_granularity to reflect the thin-pool blocksize

2014-07-09T18:18:26+00:00

commit 09869de57ed2728ae3c619803932a86cb0e2c4f8 upstream.

DM thinp already checks whether the discard_granularity of the data
device is a factor of the thin-pool block size.  But when using the
dm-thin-pool's discard passdown support, DM thinp was not selecting the
max of the underlying data device's discard_granularity and the
thin-pool's block size.

Update set_discard_limits() to set discard_granularity to the max of
these values.  This enables blkdev_issue_discard() to properly align the
discards that are sent to the DM thin device on a full block boundary.
As such each discard will now cover an entire DM thin-pool block and the
block will be reclaimed.

Reported-by: Zdenek Kabelac 
Signed-off-by: Lukas Czerner 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

md: always set MD_RECOVERY_INTR when interrupting a reshape thread.

2014-06-11T18:54:11+00:00

commit 2ac295a544dcae9299cba13ce250419117ae7fd1 upstream.

Commit 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97
   md: fix problem when adding device to read-only array with bitmap.

added a called to md_reap_sync_thread() which cause a reshape thread
to be interrupted (in particular, it could cause md_thread() to never even
call md_do_sync()).
However it didn't set MD_RECOVERY_INTR so ->finish_reshape() would not
know that the reshape didn't complete.

This only happens when mddev->ro is set and normally reshape threads
don't run in that situation.  But raid5 and raid10 can start a reshape
thread during "run" is the array is in the middle of a reshape.
They do this even if ->ro is set.

So it is best to set MD_RECOVERY_INTR before abortingg the
sync thread, just in case.

Though it rare for this to trigger a problem it can cause data corruption
because the reshape isn't finished properly.
So it is suitable for any stable which the offending commit was applied to.
(3.2 or later)

Fixes: 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md: always set MD_RECOVERY_INTR when aborting a reshape or other "resync".

2014-06-11T18:54:11+00:00

commit 3991b31ea072b070081ca3bfa860a077eda67de5 upstream.

If mddev->ro is set, md_to_sync will (correctly) abort.
However in that case MD_RECOVERY_INTR isn't set.

If a RESHAPE had been requested, then ->finish_reshape() will be
called and it will think the reshape was successful even though
nothing happened.

Normally a resync will not be requested if ->ro is set, but if an
array is stopped while a reshape is on-going, then when the array is
started, the reshape will be restarted.  If the array is also set
read-only at this point, the reshape will instantly appear to success,
resulting in data corruption.

Consequently, this patch is suitable for any -stable kernel.

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

dm cache: always split discards on cache block boundaries

2014-06-11T18:54:10+00:00

commit f1daa838e861ae1a0fb7cd9721a21258430fcc8c upstream.

The DM cache target cannot cope with discards that span multiple cache
blocks, so each discard bio that spans more than one cache block must
get split by the DM core.

Signed-off-by: Heinz Mauelshagen 
Acked-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin: add 'no_space_timeout' dm-thin-pool module param

2014-06-11T18:54:10+00:00

commit 80c578930ce77ba8bcfb226a184b482020bdda7b upstream.

Commit 85ad643b ("dm thin: add timeout to stop out-of-data-space mode
holding IO forever") introduced a fixed 60 second timeout.  Users may
want to either disable or modify this timeout.

Allow the out-of-data-space timeout to be configured using the
'no_space_timeout' dm-thin-pool module param.  Setting it to 0 will
disable the timeout, resulting in IO being queued until more data space
is added to the thin-pool.

Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin: add timeout to stop out-of-data-space mode holding IO forever

2014-06-07T17:28:25+00:00

commit 85ad643b7e7e52d37620fb272a9fd577a8095647 upstream.

If the pool runs out of data space, dm-thin can be configured to
either error IOs that would trigger provisioning, or hold those IOs
until the pool is resized.  Unfortunately, holding IOs until the pool is
resized can result in a cascade of tasks hitting the hung_task_timeout,
which may render the system unavailable.

Add a fixed timeout so IOs can only be held for a maximum of 60 seconds.
If LVM is going to resize a thin-pool that is out of data space it needs
to be prompt about it.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin: allow metadata commit if pool is in PM_OUT_OF_DATA_SPACE mode

2014-06-07T17:28:25+00:00

commit 8d07e8a5f5bc7b90f755d9b427ea930024f4c986 upstream.

Commit 3e1a0699 ("dm thin: fix out of data space handling") introduced
a regression in the metadata commit() method by returning an error if
the pool is in PM_OUT_OF_DATA_SPACE mode.  This oversight caused a thin
device to return errors even if the default queue_if_no_space ENOSPC
handling mode is used.

Fix commit() to only fail if pool is in PM_READ_ONLY or PM_FAIL mode.

Reported-by: qindehua@163.com
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman