linux-toradex.git/drivers/md, branch v2.6.32.14

md/raid6: Fix raid-6 read-error correction in degraded state

2010-05-12T21:57:15+00:00

commit 87aa63000c484bfb9909989316f615240dfee018 upstream.

Fix: Raid-6 was not trying to correct a read-error when in
singly-degraded state and was instead dropping one more device, going to
doubly-degraded state. This patch fixes this behaviour.

Tested-by: Janos Haar 
Signed-off-by: Gabriele A. Trombetti 
Reported-by: Janos Haar 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md: restore ability of spare drives to spin down.

2010-05-12T21:57:14+00:00

commit 1176568de7e066c0be9e46c37503b9fd4730edcf upstream.

Some time ago we stopped the clean/active metadata updates
from being written to a 'spare' device in most cases so that
it could spin down and say spun down.  Device failure/removal
etc are still recorded on spares.

However commit 51d5668cb2e3fd1827a55 broke this 50% of the time,
depending on whether the event count is even or odd.
The change log entry said:

   This means that the alignment between 'odd/even' and
    'clean/dirty' might take a little longer to attain,

how ever the code makes no attempt to create that alignment, so it
could take arbitrarily long.

So when we find that clean/dirty is not aligned with odd/even,
force a second metadata-update immediately.  There are already cases
where a second metadata-update is needed immediately (e.g. when a
device fails during the metadata update).  We just piggy-back on that.

Reported-by: Joe Bryant 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md/raid5: fix previous patch.

2010-05-12T21:56:59+00:00

commit 6e3b96ed610e5a1838e62ddae9fa0c3463f235fa upstream.

Previous patch changes stripe and chunk_number to sector_t but
mistakenly did not update all of the divisions to use sector_dev().

This patch changes all the those divisions (actually the '%' operator)
to sector_div.

Signed-off-by: NeilBrown 
Tested-by: Stefan Lippers-Hollmann 
Signed-off-by: Greg Kroah-Hartman

md/raid5: allow for more than 2^31 chunks.

2010-05-12T21:56:59+00:00

commit 35f2a591192d0a5d9f7fc696869c76f0b8e49c3d upstream.

With many large drives and small chunk sizes it is possible
to create a RAID5 with more than 2^31 chunks.  Make sure this
works.

Reported-by: Brett King 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md: deal with merge_bvec_fn in component devices better.

2010-04-26T14:41:35+00:00

commit 627a2d3c29427637f4c5d31ccc7fcbd8d312cd71 upstream.

If a component device has a merge_bvec_fn then as we never call it
we must ensure we never need to.  Currently this is done by setting
max_sector to 1 PAGE, however this does not stop a bio being created
with several sub-page iovecs that would violate the merge_bvec_fn.

So instead set max_phys_segments to 1 and set the segment boundary to the
same as a page boundary to ensure there is only ever one single-page
segment of IO requested at a time.

This can particularly be an issue when 'xen' is used as it is
known to submit multiple small buffers in a single bio.

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

dm mpath: fix stall when requeueing io

2010-04-26T14:41:29+00:00

upstream commit 9eef87da2a8ea4920e0d913ff977cac064b68ee0 backported to
2.6.32.10 by Nikanth Karthikesan 

This patch fixes the problem that system may stall if target's ->map_rq
returns DM_MAPIO_REQUEUE in map_request().
E.g. stall happens on 1 CPU box when a dm-mpath device with queue_if_no_path
     bounces between all-paths-down and paths-up on I/O load.

When target's ->map_rq returns DM_MAPIO_REQUEUE, map_request() requeues
the request and returns to dm_request_fn().  Then, dm_request_fn()
doesn't exit the I/O dispatching loop and continues processing
the requeued request again.
This map and requeue loop can be done with interrupt disabled,
so 1 CPU system can be stalled if this situation happens.

For example, commands below can stall my 1 CPU box within 1 minute or so:
  # dmsetup table mp
  mp: 0 2097152 multipath 1 queue_if_no_path 0 1 1 service-time 0 1 2 8:144 1 1
  # while true; do dd if=/dev/mapper/mp of=/dev/null bs=1M count=100; done &
  # while true; do \
  > dmsetup message mp 0 "fail_path 8:144" \
  > dmsetup suspend --noflush mp \
  > dmsetup resume mp \
  > dmsetup message mp 0 "reinstate_path 8:144" \
  > done

To fix the problem above, this patch changes dm_request_fn() to exit
the I/O dispatching loop once if a request is requeued in map_request().

Signed-off-by: Kiyoshi Ueda 
Signed-off-by: Jun'ichi Nomura 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Nikanth Karthikesan 
Signed-off-by: Greg Kroah-Hartman

dm: free dm_io before bio_endio not after

2010-03-15T15:50:14+00:00

commit a97f925a32aad2a37971d7bfb657006acf04e42d upstream.

Free the dm_io structure before calling bio_endio() instead of after it,
to ensure that the io_pool containing it is not referenced after it is
freed.

This partially fixes a problem described here
  https://www.redhat.com/archives/dm-devel/2010-February/msg00109.html

thread 1:
bio_endio(bio, io_error);
/* scheduling happens */
					thread 2:
					close the device
					remove the device
thread 1:
free_io(md, io);

Thread 2, when removing the device, sees non-empty md->io_pool (because the
io hasn't been freed by thread 1 yet) and may crash with BUG in mempool_free.
Thread 1 may also crash, when freeing into a nonexisting mempool.

To fix this we must make sure that bio_endio() is the last call and
the md structure is not accessed afterwards.

There is another bio_endio in process_barrier, but it is called from the thread
and the thread is destroyed prior to freeing the mempools, so this call is
not affected by the bug.

A similar bug exists with module unloads - the module may be unloaded
immediately after bio_endio - but that is more difficult to fix.

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

dm log: userspace fix overhead_size calcuations

2010-02-23T15:37:58+00:00

commit ebfd32bba9b518d684009d9d21a56742337ca1b3 upstream.

This patch fixes two bugs that revolve around the miscalculation and
misuse of the variable 'overhead_size'.  'overhead_size' is the size of
the various header structures used during communication.

The first bug is the use of 'sizeof' with the pointer of a structure
instead of the structure itself - resulting in the wrong size being
computed.  This is then used in a check to see if the payload
(data_size) would be to large for the preallocated structure.  Since the
bug produces a smaller value for the overhead, it was possible for the
structure to be breached.  (Although the current users of the code do
not currently send enough data to trigger this bug.)

The second bug is that the 'overhead_size' value is used to compute how
much of the preallocated space should be cleared before populating it
with fresh data.  This should have simply been 'sizeof(struct cn_msg)'
not overhead_size.  The fact that 'overhead_size' was computed
incorrectly made this problem "less bad" - leaving only a pointer's
worth of space at the end uncleared.  Thus, this bug was never producing
a bad result, but still needs to be fixed - especially now that the
value is computed correctly.

Signed-off-by: Jonathan Brassow 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Greg Kroah-Hartman

dm stripe: avoid divide by zero with invalid stripe count

2010-02-23T15:37:58+00:00

commit 781248c1b50c776a9ef4be1130f84ced1cba42fe upstream.

If a table containing zero as stripe count is passed into stripe_ctr
the code attempts to divide by zero.

This patch changes DM_TABLE_LOAD to return -EINVAL if the stripe count
is zero.

We now get the following error messages:
  device-mapper: table: 253:0: striped: Invalid stripe count
  device-mapper: ioctl: error adding target to table

Signed-off-by: Nikanth Karthikesan 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Greg Kroah-Hartman

md: fix 'degraded' calculation when starting a reshape.

2010-02-23T15:37:51+00:00

commit 9eb07c259207d048e3ee8be2a77b2a4680b1edd4 upstream.

This code was written long ago when it was not possible to
reshape a degraded array.  Now it is so the current level of
degraded-ness needs to be taken in to account.  Also newly addded
devices should only reduce degradedness if they are deemed to be
in-sync.

In particular, if you convert a RAID5 to a RAID6, and increase the
number of devices at the same time, then the 5->6 conversion will
make the array degraded so the current code will produce a wrong
value for 'degraded' - "-1" to be precise.

If the reshape runs to completion end_reshape will calculate a correct
new value for 'degraded', but if a device fails during the reshape an
incorrect decision might be made based on the incorrect value of
"degraded".

This patch is suitable for 2.6.32-stable and if they are still open,
2.6.31-stable and 2.6.30-stable as well.

Reported-by: Michael Evans 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman