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  1. Oct 18, 2011
  3. Oct 11, 2011
  5. Oct 07, 2011
  7. Sep 23, 2011
    • Daniel P. Berrange's avatar
      md: don't delay reboot by 1 second if no MD devices exist · 2dba6a91
      Daniel P. Berrange authored 
      

The md_notify_reboot() method includes a call to mdelay(1000),
to deal with "exotic SCSI devices" which are too volatile on
reboot. The delay is unconditional. Even if the machine does
not have any block devices, let alone MD devices, the kernel
shutdown sequence is slowed down.

1 second does not matter much with physical hardware, but with
certain virtualization use cases any wasted time in the bootup
& shutdown sequence counts for alot.

* drivers/md/md.c: md_notify_reboot() - only impose a delay if
  there was at least one MD device to be stopped during reboot

Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      2dba6a91
  9. Sep 21, 2011
    • Wang Sheng-Hui's avatar
      trival: md_k.h should be md.h in the beginning comment of file md.h · 7e841526
      Wang Sheng-Hui authored 
      

Signed-off-by: default avatarWang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      7e841526
    • NeilBrown's avatar
      md/bitmap: improve handling of 'allclean'. · 2585f3ef
      NeilBrown authored 
      

The 'allclean' flag is used to cache the fact that there is nothing to
do, so we can avoid waking up and scanning the bitmap regularly.

The two sorts of pages that might need the attention of the bitmap
daemon are BITMAP_PAGE_PENDING and BITMAP_PAGE_NEEDWRITE pages.

So make sure allclean reflects exactly when there are none of those.
So:
  set it before scanning all pages with either bit set.
  clear it whenever these bits are set
  clear it when we desire not to clear one of these bits.
  don't clear it any other time.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      2585f3ef
    • NeilBrown's avatar
      md/bitmap: rename and tidy up BITMAP_PAGE_CLEAN · 5a537df4
      NeilBrown authored 
      

The flag 'BITMAP_PAGE_CLEAN' has a confusing name as it doesn't mean
that the page is clean, but rather that there are counters in the page
which allow bits in the bitmap to be cleared - i.e. maybe cleaning can
happen.

So change it to BITMAP_PAGE_PENDING and fix some irregularities:
 - Don't set it in bitmap_init_from_disk as bitmap_set_memory_bits
   sets it when needed
 - in bitmap_daemon_work, if we find a counter that is '1', but
   need_sync is set, then set BITMAP_PAGE_PENDING again (it was
   recently cleared) to ensure we don't forget about this bit.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      5a537df4
    • NeilBrown's avatar
      md: Avoid waking up a thread after it has been freed. · 01f96c0a
      NeilBrown authored 
      

Two related problems:

1/ some error paths call "md_unregister_thread(mddev->thread)"
   without subsequently clearing ->thread.  A subsequent call
   to mddev_unlock will try to wake the thread, and crash.

2/ Most calls to md_wakeup_thread are protected against the thread
   disappeared either by:
      - holding the ->mutex
      - having an active request, so something else must be keeping
        the array active.
   However mddev_unlock calls md_wakeup_thread after dropping the
   mutex and without any certainty of an active request, so the
   ->thread could theoretically disappear.
   So we need a spinlock to provide some protections.

So change md_unregister_thread to take a pointer to the thread
pointer, and ensure that it always does the required locking, and
clears the pointer properly.

Reported-by: default avatar"Moshe Melnikov" <moshe@zadarastorage.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
cc: stable@kernel.org
      01f96c0a
  11. Sep 10, 2011
    • NeilBrown's avatar
      md: Fix handling for devices from 2TB to 4TB in 0.90 metadata. · 27a7b260
      NeilBrown authored 
      

0.90 metadata uses an unsigned 32bit number to count the number of
kilobytes used from each device.
This should allow up to 4TB per device.
However we multiply this by 2 (to get sectors) before casting to a
larger type, so sizes above 2TB get truncated.

Also we allow rdev->sectors to be larger than 4TB, so it is possible
for the array to be resized larger than the metadata can handle.
So make sure rdev->sectors never exceeds 4TB when 0.90 metadata is in
used.

Also the sanity check at the end of super_90_load should include level
1 as it used ->size too. (RAID0 and Linear don't use ->size at all).

Reported-by: default avatarPim Zandbergen <P.Zandbergen@macroscoop.nl>
Cc: stable@kernel.org
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      27a7b260
    • NeilBrown's avatar
      md/raid1,10: Remove use-after-free bug in make_request. · 079fa166
      NeilBrown authored 
      A single request to RAID1 or RAID10 might result in multiple
requests if there are known bad blocks that need to be avoided.

To detect if we need to submit another write request we test:
 	if (sectors_handled < (bio->bi_size >> 9)) {

However this is after we call **_write_done() so the 'bio' no longer
belongs to us - the writes could have completed and the bio freed.

So move the **_write_done call until after the test against
bio->bi_size.

This addresses https://bugzilla.kernel.org/show_bug.cgi?id=41862



Reported-by: default avatarBruno Wolff III <bruno@wolff.to>
Tested-by: default avatarBruno Wolff III <bruno@wolff.to>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      079fa166
    • NeilBrown's avatar
      md/raid10: unify handling of write completion. · 19d5f834
      NeilBrown authored 
      

A write can complete at two different places:
1/ when the last member-device write completes, through
   raid10_end_write_request
2/ in make_request() when we remove the initial bias from ->remaining.

These two should do exactly the same thing and the comment says they
do, but they don't.

So factor the correct code out into a function and call it in both
places.  This makes the code much more similar to RAID1.

The difference is only significant if there is an error, and they
usually take a while, so it is unlikely that there will be an error
already when make_request is completing, so this is unlikely to cause
real problems.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      19d5f834
    • NeilBrown's avatar
      Avoid dereferencing a 'request_queue' after last close. · 94007751
      NeilBrown authored 
      On the last close of an 'md' device which as been stopped, the device
is destroyed and in particular the request_queue is freed.  The free
is done in a separate thread so it might happen a short time later.

__blkdev_put calls bdev_inode_switch_bdi *after* ->release has been
called.

Since commit f758eeab


bdev_inode_switch_bdi will dereference the 'old' bdi, which lives
inside a request_queue, to get a spin lock.  This causes the last
close on an md device to sometime take a spin_lock which lives in
freed memory - which results in an oops.

So move the called to bdev_inode_switch_bdi before the call to
->release.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Cc: stable@kernel.org
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      94007751
  13. Aug 31, 2011
    • NeilBrown's avatar
      md/raid5: fix a hang on device failure. · 43220aa0
      NeilBrown authored 
      

Waiting for a 'blocked' rdev to become unblocked in the raid5d thread
cannot work with internal metadata as it is the raid5d thread which
will clear the blocked flag.
This wasn't a problem in 3.0 and earlier as we only set the blocked
flag when external metadata was used then.
However we now set it always, so we need to be more careful.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
      43220aa0
  15. Aug 30, 2011
  17. Aug 25, 2011