linux-stable.git/drivers/md/raid1.c, branch v4.2.6

md/raid1: submit_bio_wait() returns 0 on success

2015-11-09T22:37:38+00:00

commit 203d27b0226a05202438ddb39ef0ef1acb14a759 upstream.

This was introduced with 9e882242c6193ae6f416f2d8d8db0d9126bd996b
which changed the return value of submit_bio_wait() to return != 0 on
error, but didn't update the caller accordingly.

Fixes: 9e882242c6 ("block: Add submit_bio_wait(), remove from md")
Reported-by: Bill Kuzeja 
Signed-off-by: Jes Sorensen 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

md/raid1: extend spinlock to protect raid1_end_read_request against inconsistencies

2015-08-03T02:29:42+00:00

raid1_end_read_request() assumes that the In_sync bits are consistent
with the ->degaded count.
raid1_spare_active updates the In_sync bit before the ->degraded count
and so exposes an inconsistency, as does error()
So extend the spinlock in raid1_spare_active() and error() to hide those
inconsistencies.

This should probably be part of
  Commit: 34cab6f42003 ("md/raid1: fix test for 'was read error from
  last working device'.")
as it addresses the same issue.  It fixes the same bug and should go
to -stable for same reasons.

Fixes: 76073054c95b ("md/raid1: clean up read_balance.")
Cc: stable@vger.kernel.org (v3.0+)
Signed-off-by: NeilBrown

Fix read-balancing during node failure

2015-07-24T03:37:59+00:00

During a node failure, We need to suspend read balancing so that the
reads are directed to the first device and stale data is not read.
Suspending writes is not required because these would be recorded and
synced eventually.

A new flag MD_CLUSTER_SUSPEND_READ_BALANCING is set in recover_prep().
area_resyncing() will respond true for the entire devices if this
flag is set and the request type is READ. The flag is cleared
in recover_done().

Signed-off-by: Goldwyn Rodrigues 
Reported-By: David Teigland 
Signed-off-by: NeilBrown

md/raid1: fix test for 'was read error from last working device'.

2015-07-24T03:37:21+00:00

When we get a read error from the last working device, we don't
try to repair it, and don't fail the device.  We simple report a
read error to the caller.

However the current test for 'is this the last working device' is
wrong.
When there is only one fully working device, it assumes that a
non-faulty device is that device.  However a spare which is rebuilding
would be non-faulty but so not the only working device.

So change the test from "!Faulty" to "In_sync".  If ->degraded says
there is only one fully working device and this device is in_sync,
this must be the one.

This bug has existed since we allowed read_balance to read from
a recovering spare in v3.0

Reported-and-tested-by: Alexander Lyakas 
Fixes: 76073054c95b ("md/raid1: clean up read_balance.")
Cc: stable@vger.kernel.org (v3.0+)
Signed-off-by: NeilBrown

writeback: move backing_dev_info->state into bdi_writeback

2015-06-02T14:33:34+00:00

Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear.  For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi.  To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.

This patch moves bdi->state into wb.

* enum bdi_state is renamed to wb_state and the prefix of all enums is
  changed from BDI_ to WB_.

* Explicit zeroing of bdi->state is removed without adding zeoring of
  wb->state as the whole data structure is zeroed on init anyway.

* As there's still only one bdi_writeback per backing_dev_info, all
  uses of bdi->state are mechanically replaced with bdi->wb.state
  introducing no behavior changes.

Signed-off-by: Tejun Heo 
Reviewed-by: Jan Kara 
Cc: Jens Axboe 
Cc: Wu Fengguang 
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown 
Cc: Alasdair Kergon 
Cc: Mike Snitzer 
Signed-off-by: Jens Axboe

md: remove 'go_faster' option from ->sync_request()

2015-04-21T22:00:40+00:00

This option is not well justified and testing suggests that
it hardly ever makes any difference.

The comment suggests there might be a need to wait for non-resync
activity indicated by ->nr_waiting, however raise_barrier()
already waits for all of that.

So just remove it to simplify reasoning about speed limiting.

This allows us to remove a 'FIXME' comment from raid5.c as that
never used the flag.

Signed-off-by: NeilBrown

Merge branch 'cluster' into for-next

2015-04-21T22:00:20+00:00

md/raid1: fix read balance when a drive is write-mostly.

2015-02-25T00:37:02+00:00

When a drive is marked write-mostly it should only be the
target of reads if there is no other option.

This behaviour was broken by

commit 9dedf60313fa4dddfd5b9b226a0ef12a512bf9dc
    md/raid1: read balance chooses idlest disk for SSD

which causes a write-mostly device to be *preferred* is some cases.

Restore correct behaviour by checking and setting
best_dist_disk and best_pending_disk rather than best_disk.

We only need to test one of these as they are both changed
from -1 or >=0 at the same time.

As we leave min_pending and best_dist unchanged, any non-write-mostly
device will appear better than the write-mostly device.

Reported-by: Tomáš Hodek 
Reported-by: Dark Penguin 
Signed-off-by: NeilBrown 
Link: http://marc.info/?l=linux-raid&m=135982797322422
Fixes: 9dedf60313fa4dddfd5b9b226a0ef12a512bf9dc
Cc: stable@vger.kernel.org (3.6+)

Add new disk to clustered array

2015-02-23T15:59:07+00:00

Algorithm:
1. Node 1 issues mdadm --manage /dev/mdX --add /dev/sdYY which issues
   ioctl(ADD_NEW_DISC with disc.state set to MD_DISK_CLUSTER_ADD)
2. Node 1 sends NEWDISK with uuid and slot number
3. Other nodes issue kobject_uevent_env with uuid and slot number
(Steps 4,5 could be a udev rule)
4. In userspace, the node searches for the disk, perhaps
   using blkid -t SUB_UUID=""
5. Other nodes issue either of the following depending on whether the disk
   was found:
   ioctl(ADD_NEW_DISK with disc.state set to MD_DISK_CANDIDATE and
	 disc.number set to slot number)
   ioctl(CLUSTERED_DISK_NACK)
6. Other nodes drop lock on no-new-devs (CR) if device is found
7. Node 1 attempts EX lock on no-new-devs
8. If node 1 gets the lock, it sends METADATA_UPDATED after unmarking the disk
   as SpareLocal
9. If not (get no-new-dev lock), it fails the operation and sends METADATA_UPDATED
10. Other nodes understand if the device is added or not by reading the superblock again after receiving the METADATA_UPDATED message.

Signed-off-by: Lidong Zhong 
Signed-off-by: Goldwyn Rodrigues

Read from the first device when an area is resyncing

2015-02-23T15:59:07+00:00

set choose_first true for cluster read in read balance when the area
is resyncing.

Signed-off-by: Lidong Zhong 
Signed-off-by: Goldwyn Rodrigues