md: support blocking writes to an array on device failure
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>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index bec00b2..83eb78b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1828,6 +1828,10 @@
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 @@
* 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) {
@@ -1866,6 +1872,16 @@
} 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 @@
goto abort_free;
}
}
+
INIT_LIST_HEAD(&rdev->same_set);
+ init_waitqueue_head(&rdev->blocked_wait);
return rdev;
@@ -4958,6 +4976,9 @@
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 @@
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_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)
{