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md: support blocking writes to an array on device failure

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Allows a userspace metadata handler to take action upon detecting a device
failure.

Based on an original patch by Neil Brown.

Changes:
-added blocked_wait waitqueue to rdev
-don't qualify Blocked with Faulty always let userspace block writes
-added md_wait_for_blocked_rdev to wait for the block device to be clear, if
 userspace misses the notification another one is sent every 5 seconds
-set MD_RECOVERY_NEEDED after clearing "blocked"
-kill DoBlock flag, just test mddev->external

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams
2008-04-30 00:52:32 -07:00
committed by Linus Torvalds
parent 11e2ede022
commit 6bfe0b4990
6 changed files with 120 additions and 7 deletions
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33
drivers/md/md.c
View File

@@ -1828,6 +1828,10 @@ state_show(mdk_rdev_t *rdev, char *page)
len += sprintf(page+len, "%swrite_mostly",sep);
sep = ",";
}
if (test_bit(Blocked, &rdev->flags)) {
len += sprintf(page+len, "%sblocked", sep);
sep = ",";
}
if (!test_bit(Faulty, &rdev->flags) &&
!test_bit(In_sync, &rdev->flags)) {
len += sprintf(page+len, "%sspare", sep);
@@ -1844,6 +1848,8 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
* remove - disconnects the device
* writemostly - sets write_mostly
* -writemostly - clears write_mostly
* blocked - sets the Blocked flag
* -blocked - clears the Blocked flag
*/
int err = -EINVAL;
if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
@@ -1865,6 +1871,16 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
err = 0;
} else if (cmd_match(buf, "-writemostly")) {
clear_bit(WriteMostly, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "blocked")) {
set_bit(Blocked, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "-blocked")) {
clear_bit(Blocked, &rdev->flags);
wake_up(&rdev->blocked_wait);
set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
md_wakeup_thread(rdev->mddev->thread);
err = 0;
}
return err ? err : len;
@@ -2194,7 +2210,9 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
goto abort_free;
}
}
INIT_LIST_HEAD(&rdev->same_set);
init_waitqueue_head(&rdev->blocked_wait);
return rdev;
@@ -4958,6 +4976,9 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
if (!rdev || test_bit(Faulty, &rdev->flags))
return;
if (mddev->external)
set_bit(Blocked, &rdev->flags);
/*
dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
mdname(mddev),
@@ -5760,7 +5781,7 @@ static int remove_and_add_spares(mddev_t *mddev)
rdev_for_each(rdev, rtmp, mddev)
if (rdev->raid_disk >= 0 &&
!mddev->external &&
!test_bit(Blocked, &rdev->flags) &&
(test_bit(Faulty, &rdev->flags) ||
! test_bit(In_sync, &rdev->flags)) &&
atomic_read(&rdev->nr_pending)==0) {
@@ -5959,6 +5980,16 @@ void md_check_recovery(mddev_t *mddev)
}
}
void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
{
sysfs_notify(&rdev->kobj, NULL, "state");
wait_event_timeout(rdev->blocked_wait,
!test_bit(Blocked, &rdev->flags),
msecs_to_jiffies(5000));
rdev_dec_pending(rdev, mddev);
}
EXPORT_SYMBOL(md_wait_for_blocked_rdev);
static int md_notify_reboot(struct notifier_block *this,
unsigned long code, void *x)
{