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Message-Id: <1080627065057.10543@suse.de>
Date: Fri, 27 Jun 2008 16:50:57 +1000
From: NeilBrown <neilb@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 015 of 29] md: Make sure all changes to md/sync_action are notified.
When the 'resync' thread starts or stops, when we explicitly
set sync_action, or when we determine that there is definitely nothing
to do, we notify sync_action.
To stop "sync_action" from occasionally showing the wrong value,
we introduce a new flags - MD_RECOVERY_RECOVER - to say that a
recovery is probably needed or happening, and we make sure
that we set MD_RECOVERY_RUNNING before clearing MD_RECOVERY_NEEDED.
Signed-off-by: Neil Brown <neilb@...e.de>
### Diffstat output
./Documentation/md.txt | 6 ++++++
./drivers/md/md.c | 34 ++++++++++++++++++++++++++++------
./include/linux/raid/md_k.h | 2 ++
3 files changed, 36 insertions(+), 6 deletions(-)
diff .prev/Documentation/md.txt ./Documentation/md.txt
--- .prev/Documentation/md.txt 2008-06-27 16:22:01.000000000 +1000
+++ ./Documentation/md.txt 2008-06-27 16:22:02.000000000 +1000
@@ -386,6 +386,12 @@ also have
'check' and 'repair' will start the appropriate process
providing the current state is 'idle'.
+ This file responds to select/poll. Any important change in the value
+ triggers a poll event. Sometimes the value will briefly be
+ "recover" if a recovery seems to be needed, but cannot be
+ achieved. In that case, the transition to "recover" isn't
+ notified, but the transition away is.
+
mismatch_count
When performing 'check' and 'repair', and possibly when
performing 'resync', md will count the number of errors that are
diff .prev/drivers/md/md.c ./drivers/md/md.c
--- .prev/drivers/md/md.c 2008-06-27 16:22:01.000000000 +1000
+++ ./drivers/md/md.c 2008-06-27 16:22:02.000000000 +1000
@@ -169,7 +169,6 @@ void md_new_event(mddev_t *mddev)
{
atomic_inc(&md_event_count);
wake_up(&md_event_waiters);
- sysfs_notify(&mddev->kobj, NULL, "sync_action");
}
EXPORT_SYMBOL_GPL(md_new_event);
@@ -2936,7 +2935,7 @@ action_show(mddev_t *mddev, char *page)
type = "check";
else
type = "repair";
- } else
+ } else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
type = "recover";
}
return sprintf(page, "%s\n", type);
@@ -2958,9 +2957,12 @@ action_store(mddev_t *mddev, const char
} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
return -EBUSY;
- else if (cmd_match(page, "resync") || cmd_match(page, "recover"))
+ else if (cmd_match(page, "resync"))
+ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ else if (cmd_match(page, "recover")) {
+ set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- else if (cmd_match(page, "reshape")) {
+ } else if (cmd_match(page, "reshape")) {
int err;
if (mddev->pers->start_reshape == NULL)
return -EINVAL;
@@ -2977,6 +2979,7 @@ action_store(mddev_t *mddev, const char
}
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
+ sysfs_notify(&mddev->kobj, NULL, "sync_action");
return len;
}
@@ -3682,6 +3685,7 @@ static int do_md_run(mddev_t * mddev)
mddev->changed = 1;
md_new_event(mddev);
sysfs_notify(&mddev->kobj, NULL, "array_state");
+ sysfs_notify(&mddev->kobj, NULL, "sync_action");
kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
return 0;
}
@@ -4252,6 +4256,8 @@ static int add_new_disk(mddev_t * mddev,
export_rdev(rdev);
md_update_sb(mddev, 1);
+ if (mddev->degraded)
+ set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
return err;
@@ -5105,6 +5111,8 @@ void md_error(mddev_t *mddev, mdk_rdev_t
if (!mddev->pers->error_handler)
return;
mddev->pers->error_handler(mddev,rdev);
+ if (mddev->degraded)
+ set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
@@ -6055,13 +6063,18 @@ void md_check_recovery(mddev_t *mddev)
mddev->recovery = 0;
/* flag recovery needed just to double check */
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ sysfs_notify(&mddev->kobj, NULL, "sync_action");
md_new_event(mddev);
goto unlock;
}
+ /* Set RUNNING before clearing NEEDED to avoid
+ * any transients in the value of "sync_action".
+ */
+ set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+ clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
/* Clear some bits that don't mean anything, but
* might be left set
*/
- clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
@@ -6079,17 +6092,19 @@ void md_check_recovery(mddev_t *mddev)
/* Cannot proceed */
goto unlock;
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
+ clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
} else if ((spares = remove_and_add_spares(mddev))) {
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+ set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
} else if (mddev->recovery_cp < MaxSector) {
set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+ clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
/* nothing to be done ... */
goto unlock;
if (mddev->pers->sync_request) {
- set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
if (spares && mddev->bitmap && ! mddev->bitmap->file) {
/* We are adding a device or devices to an array
* which has the bitmap stored on all devices.
@@ -6108,9 +6123,16 @@ void md_check_recovery(mddev_t *mddev)
mddev->recovery = 0;
} else
md_wakeup_thread(mddev->sync_thread);
+ sysfs_notify(&mddev->kobj, NULL, "sync_action");
md_new_event(mddev);
}
unlock:
+ if (!mddev->sync_thread) {
+ clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+ if (test_and_clear_bit(MD_RECOVERY_RECOVER,
+ &mddev->recovery))
+ sysfs_notify(&mddev->kobj, NULL, "sync_action");
+ }
mddev_unlock(mddev);
}
}
diff .prev/include/linux/raid/md_k.h ./include/linux/raid/md_k.h
--- .prev/include/linux/raid/md_k.h 2008-06-27 16:20:34.000000000 +1000
+++ ./include/linux/raid/md_k.h 2008-06-27 16:22:02.000000000 +1000
@@ -188,6 +188,7 @@ struct mddev_s
* NEEDED: we might need to start a resync/recover
* RUNNING: a thread is running, or about to be started
* SYNC: actually doing a resync, not a recovery
+ * RECOVER: doing recovery, or need to try it.
* INTR: resync needs to be aborted for some reason
* DONE: thread is done and is waiting to be reaped
* REQUEST: user-space has requested a sync (used with SYNC)
@@ -198,6 +199,7 @@ struct mddev_s
*/
#define MD_RECOVERY_RUNNING 0
#define MD_RECOVERY_SYNC 1
+#define MD_RECOVERY_RECOVER 2
#define MD_RECOVERY_INTR 3
#define MD_RECOVERY_DONE 4
#define MD_RECOVERY_NEEDED 5
--
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