When we have externally managed metadata, we need to mark a failed
device as 'Blocked' and not allow any writes until that device
have been marked as faulty in the metadata and the Blocked flag has
been removed.

However it is perfectly OK to allow read requests when there is a
Blocked device, and with a readonly array, there may not be any
metadata-handler watching for blocked devices.

So in raid5/raid6 only allow a Blocked device to interfere with
Write request or resync.  Read requests go through untouched.

raid1 and raid10 already differentiate between read and write
properly.

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

We cannot currently change the size of a write-intent bitmap.
So if we change the size of an array which has such a bitmap, it
tries to set bits beyond the end of the bitmap.

For now, simply reject any request to change the size of an array
which has a bitmap.  mdadm can remove the bitmap and add a new one
after the array has changed size.

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

* 'for-linus' of git://neil.brown.name/md:
  md: raid10: wake up frozen array
  md: do not count blocked devices as spares
  md: do not progress the resync process if the stripe was blocked
  md: delay notification of 'active_idle' to the recovery thread
  md: fix merge error
  md: move async_tx_issue_pending_all outside spin_lock_irq

handle_stripe will take no action on a stripe when waiting for userspace
to unblock the array, so do not report completed sectors.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The original STRIPE_OP_IO removal patch had the following hunk:

-               for (i = conf->raid_disks; i--; ) {
+               for (i = conf->raid_disks; i--; )
                        set_bit(R5_Wantwrite, &sh->dev[i].flags);
-                       if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-                               sh->ops.count++;
-               }

However it appears the hunk became broken after merging:
-               for (i = conf->raid_disks; i--; ) {
+               for (i = conf->raid_disks; i--; )
                        set_bit(R5_Wantwrite, &sh->dev[i].flags);
                        set_bit(R5_LOCKED, &dev->flags);
                        s.locked++;
-                       if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
-                               sh->ops.count++;
-               }

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Some dma drivers need to call spin_lock_bh in their device_issue_pending
routines.  This change avoids:

WARNING: at kernel/softirq.c:136 local_bh_enable_ip+0x3a/0x85()

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

* 'for-linus' of git://neil.brown.name/md: (52 commits)
  md: Protect access to mddev->disks list using RCU
  md: only count actual openers as access which prevent a 'stop'
  md: linear: Make array_size sector-based and rename it to array_sectors.
  md: Make mddev->array_size sector-based.
  md: Make super_type->rdev_size_change() take sector-based sizes.
  md: Fix check for overlapping devices.
  md: Tidy up rdev_size_store a bit:
  md: Remove some unused macros.
  md: Turn rdev->sb_offset into a sector-based quantity.
  md: Make calc_dev_sboffset() return a sector count.
  md: Replace calc_dev_size() by calc_num_sectors().
  md: Make update_size() take the number of sectors.
  md: Better control of when do_md_stop is allowed to stop the array.
  md: get_disk_info(): Don't convert between signed and unsigned and back.
  md: Simplify restart_array().
  md: alloc_disk_sb(): Return proper error value.
  md: Simplify sb_equal().
  md: Simplify uuid_equal().
  md: sb_equal(): Fix misleading printk.
  md: Fix a typo in the comment to cmd_match().
  ...

This patch renames the array_size field of struct mddev_s to array_sectors
and converts all instances to use units of 512 byte sectors instead of 1k
blocks.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (37 commits)
  splice: fix generic_file_splice_read() race with page invalidation
  ramfs: enable splice write
  drivers/block/pktcdvd.c: avoid useless memset
  cdrom: revert commit 22a9189 (cdrom: use kmalloced buffers instead of buffers on stack)
  scsi: sr avoids useless buffer allocation
  block: blk_rq_map_kern uses the bounce buffers for stack buffers
  block: add blk_queue_update_dma_pad
  DAC960: push down BKL
  pktcdvd: push BKL down into driver
  paride: push ioctl down into driver
  block: use get_unaligned_* helpers
  block: extend queue_flag bitops
  block: request_module(): use format string
  Add bvec_merge_data to handle stacked devices and ->merge_bvec()
  block: integrity flags can't use bit ops on unsigned short
  cmdfilter: extend default read filter
  sg: fix odd style (extra parenthesis) introduced by cmd filter patch
  block: add bounce support to blk_rq_map_user_iov
  cfq-iosched: get rid of enable_idle being unused warning
  allow userspace to modify scsi command filter on per device basis
  ...

Remove the dubious attempt to prefer 'compute' over 'read'.  Not only is it
wrong given commit c337869d (md: do not compute parity unless it is on a failed
drive), but it can trigger a BUG_ON in handle_parity_checks5().

Cc: <stable@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>