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Message-Id: <1060731073252.24530@suse.de>
Date: Mon, 31 Jul 2006 17:32:52 +1000
From: NeilBrown <neilb@...e.de>
To: Andrew Morton <akpm@...l.org>
Cc: linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 009 of 9] md: Improve locking around error handling.
The error handling routines don't use proper locking, and
so two concurrent errors could trigger a problem.
So:
- use test-and-set and test-and-clear to synchonise
the In_sync bits with the ->degraded count
- use the spinlock to protect updates to the
degraded count (could use an atomic_t but that
would be a bigger change in code, and isn't
really justified)
- remove un-necessary locking in raid5
Signed-off-by: Neil Brown <neilb@...e.de>
### Diffstat output
./drivers/md/raid1.c | 16 +++++++++++-----
./drivers/md/raid10.c | 12 ++++++++----
./drivers/md/raid5.c | 20 ++++++++++++--------
3 files changed, 31 insertions(+), 17 deletions(-)
diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c
--- .prev/drivers/md/raid1.c 2006-07-31 17:24:36.000000000 +1000
+++ ./drivers/md/raid1.c 2006-07-31 17:24:36.000000000 +1000
@@ -956,14 +956,16 @@ static void error(mddev_t *mddev, mdk_rd
* normal single drive
*/
return;
- if (test_bit(In_sync, &rdev->flags)) {
+ if (test_and_clear_bit(In_sync, &rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded++;
+ spin_unlock_irqrestore(&conf->device_lock, flags);
/*
* if recovery is running, make sure it aborts.
*/
set_bit(MD_RECOVERY_ERR, &mddev->recovery);
}
- clear_bit(In_sync, &rdev->flags);
set_bit(Faulty, &rdev->flags);
set_bit(MD_CHANGE_DEVS, &mddev->flags);
printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
@@ -1017,9 +1019,11 @@ static int raid1_spare_active(mddev_t *m
tmp = conf->mirrors + i;
if (tmp->rdev
&& !test_bit(Faulty, &tmp->rdev->flags)
- && !test_bit(In_sync, &tmp->rdev->flags)) {
+ && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded--;
- set_bit(In_sync, &tmp->rdev->flags);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
}
}
@@ -2034,7 +2038,7 @@ static int raid1_reshape(mddev_t *mddev)
mirror_info_t *newmirrors;
conf_t *conf = mddev_to_conf(mddev);
int cnt, raid_disks;
-
+ unsigned long flags;
int d, d2;
/* Cannot change chunk_size, layout, or level */
@@ -2093,7 +2097,9 @@ static int raid1_reshape(mddev_t *mddev)
kfree(conf->poolinfo);
conf->poolinfo = newpoolinfo;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded += (raid_disks - conf->raid_disks);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
conf->raid_disks = mddev->raid_disks = raid_disks;
mddev->delta_disks = 0;
diff .prev/drivers/md/raid10.c ./drivers/md/raid10.c
--- .prev/drivers/md/raid10.c 2006-07-31 17:24:35.000000000 +1000
+++ ./drivers/md/raid10.c 2006-07-31 17:24:36.000000000 +1000
@@ -950,14 +950,16 @@ static void error(mddev_t *mddev, mdk_rd
* really dead" tests...
*/
return;
- if (test_bit(In_sync, &rdev->flags)) {
+ if (test_and_clear_bit(In_sync, &rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded++;
+ spin_unlock_irqrestore(&conf->device_lock, flags);
/*
* if recovery is running, make sure it aborts.
*/
set_bit(MD_RECOVERY_ERR, &mddev->recovery);
}
- clear_bit(In_sync, &rdev->flags);
set_bit(Faulty, &rdev->flags);
set_bit(MD_CHANGE_DEVS, &mddev->flags);
printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
@@ -1033,9 +1035,11 @@ static int raid10_spare_active(mddev_t *
tmp = conf->mirrors + i;
if (tmp->rdev
&& !test_bit(Faulty, &tmp->rdev->flags)
- && !test_bit(In_sync, &tmp->rdev->flags)) {
+ && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded--;
- set_bit(In_sync, &tmp->rdev->flags);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
}
}
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2006-07-31 17:24:35.000000000 +1000
+++ ./drivers/md/raid5.c 2006-07-31 17:24:36.000000000 +1000
@@ -636,7 +636,6 @@ static int raid5_end_write_request (stru
struct stripe_head *sh = bi->bi_private;
raid5_conf_t *conf = sh->raid_conf;
int disks = sh->disks, i;
- unsigned long flags;
int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);
if (bi->bi_size)
@@ -654,7 +653,6 @@ static int raid5_end_write_request (stru
return 0;
}
- spin_lock_irqsave(&conf->device_lock, flags);
if (!uptodate)
md_error(conf->mddev, conf->disks[i].rdev);
@@ -662,8 +660,7 @@ static int raid5_end_write_request (stru
clear_bit(R5_LOCKED, &sh->dev[i].flags);
set_bit(STRIPE_HANDLE, &sh->state);
- __release_stripe(conf, sh);
- spin_unlock_irqrestore(&conf->device_lock, flags);
+ release_stripe(sh);
return 0;
}
@@ -697,9 +694,11 @@ static void error(mddev_t *mddev, mdk_rd
if (!test_bit(Faulty, &rdev->flags)) {
set_bit(MD_CHANGE_DEVS, &mddev->flags);
- if (test_bit(In_sync, &rdev->flags)) {
+ if (test_and_clear_bit(In_sync, &rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded++;
- clear_bit(In_sync, &rdev->flags);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
/*
* if recovery was running, make sure it aborts.
*/
@@ -3419,9 +3418,11 @@ static int raid5_spare_active(mddev_t *m
tmp = conf->disks + i;
if (tmp->rdev
&& !test_bit(Faulty, &tmp->rdev->flags)
- && !test_bit(In_sync, &tmp->rdev->flags)) {
+ && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
+ unsigned long flags;
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded--;
- set_bit(In_sync, &tmp->rdev->flags);
+ spin_unlock_irqrestore(&conf->device_lock, flags);
}
}
print_raid5_conf(conf);
@@ -3557,6 +3558,7 @@ static int raid5_start_reshape(mddev_t *
struct list_head *rtmp;
int spares = 0;
int added_devices = 0;
+ unsigned long flags;
if (mddev->degraded ||
test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
@@ -3598,7 +3600,9 @@ static int raid5_start_reshape(mddev_t *
break;
}
+ spin_lock_irqsave(&conf->device_lock, flags);
mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices;
+ spin_unlock_irqrestore(&conf->device_lock, flags);
mddev->raid_disks = conf->raid_disks;
mddev->reshape_position = 0;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
-
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