linux-stable.git/drivers/md/md.c, branch linux-3.19.y

md: fix md io stats accounting broken

2015-05-06T20:01:39+00:00

commit 74672d069b298b03e9f657fd70915e055739882e upstream.

Simon reported the md io stats accounting issue:
"
I'm seeing "iostat -x -k 1" print this after a RAID1 rebuild on 4.0-rc5.
It's not abnormal other than it's 3-disk, with one being SSD (sdc) and
the other two being write-mostly:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
sdb               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
sdc               0.00     0.00    0.00    0.00     0.00     0.00     0.00     0.00    0.00    0.00    0.00   0.00   0.00
md0               0.00     0.00    0.00    0.00     0.00     0.00     0.00   345.00    0.00    0.00    0.00   0.00 100.00
md2               0.00     0.00    0.00    0.00     0.00     0.00     0.00 58779.00    0.00    0.00    0.00   0.00 100.00
md1               0.00     0.00    0.00    0.00     0.00     0.00     0.00    12.00    0.00    0.00    0.00   0.00 100.00
"
The cause is commit "18c0b223cf9901727ef3b02da6711ac930b4e5d4" uses the
generic_start_io_acct to account the disk stats rather than the open code,
but it also introduced the increase to .in_flight[rw] which is needless to
md. So we re-use the open code here to fix it.

Reported-by: Simon Kirby 
Signed-off-by: Gu Zheng 
Signed-off-by: NeilBrown 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'md/3.19' of git://neil.brown.name/md

2014-12-14T20:13:05+00:00

Pull md updates from Neil Brown:
 "Three fixes for md.

   I did have a largish set of locking changes queued, but late testing
  showed they weren't quite as stable as I thought and while I fixed
  what I found, I decided it safer to delay them a release ...
  particularly as I'll be AFK for a few weeks.  So expect a larger batch
  next time :-)"

* tag 'md/3.19' of git://neil.brown.name/md:
  md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.
  md: fix semicolon.cocci warnings
  md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.

md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.

2014-12-10T23:02:10+00:00

A recent change to md started the ->sync_thread from a asynchronously
from a work_queue rather than synchronously.  This means that there
can be a small window between the time when MD_RECOVERY_RUNNING is set
and when ->sync_thread is set.

So code that checks ->sync_thread might now conclude that the thread
has not been started and (because a lock is held) will not be started.
That is no longer the case.

Most of those places are best fixed by testing MD_RECOVERY_RUNNING
as well.  To make this completely reliable, we wake_up(&resync_wait)
after clearing that flag as well as after clearing ->sync_thread.

Other places are better served by flushing the relevant workqueue
to ensure that that if the sync thread was starting, it has now
started.  This is particularly best if we are about to stop the
sync thread.

Fixes: ac05f256691fe427a3e84c19261adb0b67dd73c0
Signed-off-by: NeilBrown

md: fix semicolon.cocci warnings

2014-12-03T05:07:59+00:00

drivers/md/md.c:7175:43-44: Unneeded semicolon

 Removes unneeded semicolon.

Generated by: scripts/coccinelle/misc/semicolon.cocci

Signed-off-by: Fengguang Wu 
Signed-off-by: NeilBrown

md: use generic io stats accounting functions to simplify io stat accounting

2014-11-24T15:05:16+00:00

Use generic io stats accounting help functions (generic_{start,end}_io_acct)
to simplify io stat accounting.

Signed-off-by: Gu Zheng 
Signed-off-by: Jens Axboe

md: Always set RECOVERY_NEEDED when clearing RECOVERY_FROZEN

2014-11-16T22:17:46+00:00

md_check_recovery will skip any recovery and also clear
MD_RECOVERY_NEEDED if MD_RECOVERY_FROZEN is set.
So when we clear _FROZEN, we must set _NEEDED and ensure that
md_check_recovery gets run.
Otherwise we could miss out on something that is needed.

In particular, this can make it impossible to remove a
failed device from an array is the  'recovery-needed' processing
didn't happen.
Suitable for stable kernels since 3.13.

Cc: stable@vger.kernel.org (3.13+)
Reported-and-tested-by: Joe Lawrence 
Fixes: 30b8feb730f9b9b3c5de02580897da03f59b6b16
Signed-off-by: NeilBrown

md: move EXPORT_SYMBOL to after function in md.c

2014-10-14T02:08:29+00:00

Signed-off-by: NeilBrown

md: discard PRINT_RAID_DEBUG ioctl

2014-10-14T02:08:29+00:00

All the interesting information printed by this ioctl
is provided in /proc/mdstat and/or sysfs.
So it isn't needed and isn't used and would be best if it didn't
exist.

Signed-off-by: NeilBrown

md: remove MD_BUG()

2014-10-14T02:08:29+00:00

Most of the places that call this are doing so pointlessly.
A couple of the others a best replaced with WARN_ON().

Signed-off-by: NeilBrown

md: clean up 'exit' labels in md_ioctl().

2014-10-14T02:08:29+00:00

There are 4 labels and we only really need two.

Signed-off-by: NeilBrown