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md: fix md io stats accounting broken

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commit 74672d069b 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 <sim@hostway.ca>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gu Zheng
2015-04-03 08:44:47 +08:00
committed by Greg Kroah-Hartman
parent 36fb8ea947
commit 8336ee9076
1 changed files with 5 additions and 1 deletions
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6
drivers/md/md.c
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@@ -249,6 +249,7 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
const int rw = bio_data_dir(bio); const int rw = bio_data_dir(bio);
struct mddev *mddev = q->queuedata; struct mddev *mddev = q->queuedata;
unsigned int sectors; unsigned int sectors;
int cpu;
if (mddev == NULL || mddev->pers == NULL if (mddev == NULL || mddev->pers == NULL
|| !mddev->ready) { || !mddev->ready) {
@@ -284,7 +285,10 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
sectors = bio_sectors(bio); sectors = bio_sectors(bio);
mddev->pers->make_request(mddev, bio); mddev->pers->make_request(mddev, bio);
generic_start_io_acct(rw, sectors, &mddev->gendisk->part0); cpu = part_stat_lock();
part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
part_stat_unlock();
if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended) if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
wake_up(&mddev->sb_wait); wake_up(&mddev->sb_wait);