md-cluster: Perform a lazy update
In a clustered environment, a change such as marking a device faulty,
can be recorded by any of the nodes. This is communicated to all the
nodes and re-recording such a change is unnecessary, and quite often
pretty disruptive.
With this patch, just before the update, we detect for the changes
and if the changes are already in superblock, we abort the update
after clearing all the flags
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 12cc28a..5f09678 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2199,6 +2199,46 @@
}
}
+static bool does_sb_need_changing(struct mddev *mddev)
+{
+ struct md_rdev *rdev;
+ struct mdp_superblock_1 *sb;
+ int role;
+
+ /* Find a good rdev */
+ rdev_for_each(rdev, mddev)
+ if ((rdev->raid_disk >= 0) && !test_bit(Faulty, &rdev->flags))
+ break;
+
+ /* No good device found. */
+ if (!rdev)
+ return false;
+
+ sb = page_address(rdev->sb_page);
+ /* Check if a device has become faulty or a spare become active */
+ rdev_for_each(rdev, mddev) {
+ role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
+ /* Device activated? */
+ if (role == 0xffff && rdev->raid_disk >=0 &&
+ !test_bit(Faulty, &rdev->flags))
+ return true;
+ /* Device turned faulty? */
+ if (test_bit(Faulty, &rdev->flags) && (role < 0xfffd))
+ return true;
+ }
+
+ /* Check if any mddev parameters have changed */
+ if ((mddev->dev_sectors != le64_to_cpu(sb->size)) ||
+ (mddev->reshape_position != le64_to_cpu(sb->reshape_position)) ||
+ (mddev->recovery_cp != le64_to_cpu(sb->resync_offset)) ||
+ (mddev->layout != le64_to_cpu(sb->layout)) ||
+ (mddev->raid_disks != le32_to_cpu(sb->raid_disks)) ||
+ (mddev->chunk_sectors != le32_to_cpu(sb->chunksize)))
+ return true;
+
+ return false;
+}
+
void md_update_sb(struct mddev *mddev, int force_change)
{
struct md_rdev *rdev;
@@ -2211,6 +2251,18 @@
set_bit(MD_CHANGE_DEVS, &mddev->flags);
return;
}
+
+ if (mddev_is_clustered(mddev)) {
+ if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
+ force_change = 1;
+ md_cluster_ops->metadata_update_start(mddev);
+ /* Has someone else has updated the sb */
+ if (!does_sb_need_changing(mddev)) {
+ md_cluster_ops->metadata_update_cancel(mddev);
+ clear_bit(MD_CHANGE_PENDING, &mddev->flags);
+ return;
+ }
+ }
repeat:
/* First make sure individual recovery_offsets are correct */
rdev_for_each(rdev, mddev) {
@@ -2359,6 +2411,9 @@
clear_bit(BlockedBadBlocks, &rdev->flags);
wake_up(&rdev->blocked_wait);
}
+
+ if (mddev_is_clustered(mddev))
+ md_cluster_ops->metadata_update_finish(mddev);
}
EXPORT_SYMBOL(md_update_sb);
@@ -2496,13 +2551,9 @@
if (mddev_is_clustered(mddev))
md_cluster_ops->remove_disk(mddev, rdev);
md_kick_rdev_from_array(rdev);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
if (mddev->pers)
md_update_sb(mddev, 1);
md_new_event(mddev);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
err = 0;
}
} else if (cmd_match(buf, "writemostly")) {
@@ -4063,12 +4114,8 @@
if (err)
return err;
if (mddev->pers) {
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
err = update_size(mddev, sectors);
md_update_sb(mddev, 1);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
} else {
if (mddev->dev_sectors == 0 ||
mddev->dev_sectors > sectors)
@@ -5306,8 +5353,6 @@
static void __md_stop_writes(struct mddev *mddev)
{
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
flush_workqueue(md_misc_wq);
if (mddev->sync_thread) {
@@ -5326,8 +5371,6 @@
mddev->in_sync = 1;
md_update_sb(mddev, 1);
}
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
}
void md_stop_writes(struct mddev *mddev)
@@ -6015,9 +6058,6 @@
md_update_sb(mddev, 1);
md_new_event(mddev);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
-
return 0;
busy:
if (mddev_is_clustered(mddev))
@@ -6073,14 +6113,12 @@
goto abort_export;
}
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
clear_bit(In_sync, &rdev->flags);
rdev->desc_nr = -1;
rdev->saved_raid_disk = -1;
err = bind_rdev_to_array(rdev, mddev);
if (err)
- goto abort_clustered;
+ goto abort_export;
/*
* The rest should better be atomic, we can have disk failures
@@ -6090,9 +6128,6 @@
rdev->raid_disk = -1;
md_update_sb(mddev, 1);
-
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
/*
* Kick recovery, maybe this spare has to be added to the
* array immediately.
@@ -6102,9 +6137,6 @@
md_new_event(mddev);
return 0;
-abort_clustered:
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_cancel(mddev);
abort_export:
export_rdev(rdev);
return err;
@@ -6422,8 +6454,6 @@
return rv;
}
}
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
rv = update_size(mddev, (sector_t)info->size * 2);
@@ -6481,12 +6511,8 @@
}
}
md_update_sb(mddev, 1);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
return rv;
err:
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_cancel(mddev);
return rv;
}
@@ -7599,11 +7625,7 @@
mddev->safemode == 0)
mddev->safemode = 1;
spin_unlock(&mddev->lock);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
md_update_sb(mddev, 0);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
sysfs_notify_dirent_safe(mddev->sysfs_state);
} else
spin_unlock(&mddev->lock);
@@ -8182,13 +8204,8 @@
sysfs_notify_dirent_safe(mddev->sysfs_state);
}
- if (mddev->flags & MD_UPDATE_SB_FLAGS) {
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
+ if (mddev->flags & MD_UPDATE_SB_FLAGS)
md_update_sb(mddev, 0);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
- }
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
!test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
@@ -8286,8 +8303,6 @@
set_bit(MD_CHANGE_DEVS, &mddev->flags);
}
}
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_start(mddev);
if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
mddev->pers->finish_reshape)
mddev->pers->finish_reshape(mddev);
@@ -8300,8 +8315,6 @@
rdev->saved_raid_disk = -1;
md_update_sb(mddev, 1);
- if (mddev_is_clustered(mddev))
- md_cluster_ops->metadata_update_finish(mddev);
clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);