md-cluster: add the support for resize

To update size for cluster raid, we need to make
sure all nodes can perform the change successfully.
However, it is possible that some of them can't do
it due to failure (bitmap_resize could fail). So
we need to consider the issue before we set the
capacity unconditionally, and we use below steps
to perform sanity check.

1. A change the size, then broadcast METADATA_UPDATED
   msg.
2. B and C receive METADATA_UPDATED change the size
   excepts call set_capacity, sync_size is not update
   if the change failed. Also call bitmap_update_sb
   to sync sb to disk.
3. A checks other node's sync_size, if sync_size has
   been updated in all nodes, then send CHANGE_CAPACITY
   msg otherwise send msg to revert previous change.
4. B and C call set_capacity if receive CHANGE_CAPACITY
   msg, otherwise pers->resize will be called to restore
   the old value.

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/Documentation/md/md-cluster.txt b/Documentation/md/md-cluster.txt
index 38883276d31c379fe6de344537b08d0b4e10e6a9..2663d49dd8a0530a64e9e4c4cba152b2b0868202 100644 (file)
--- a/Documentation/md/md-cluster.txt
+++ b/Documentation/md/md-cluster.txt
@@ -321,4 +321,4 @@ The algorithm is:
 
 There are somethings which are not supported by cluster MD yet.
 
-- update size and change array_sectors.
+- change array_sectors.

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 92c3c51ede4d3199af6672865af7c183d131a415..b21ef58819f695acf5b95361cb2dfa4694f9a6fa 100644 (file)
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -1151,6 +1151,81 @@ int cluster_check_sync_size(struct mddev *mddev)
        return (my_sync_size == sync_size) ? 0 : -1;
 }
 
+/*
+ * Update the size for cluster raid is a little more complex, we perform it
+ * by the steps:
+ * 1. hold token lock and update superblock in initiator node.
+ * 2. send METADATA_UPDATED msg to other nodes.
+ * 3. The initiator node continues to check each bitmap's sync_size, if all
+ *    bitmaps have the same value of sync_size, then we can set capacity and
+ *    let other nodes to perform it. If one node can't update sync_size
+ *    accordingly, we need to revert to previous value.
+ */
+static void update_size(struct mddev *mddev, sector_t old_dev_sectors)
+{
+       struct md_cluster_info *cinfo = mddev->cluster_info;
+       struct cluster_msg cmsg;
+       struct md_rdev *rdev;
+       int ret = 0;
+       int raid_slot = -1;
+
+       md_update_sb(mddev, 1);
+       lock_comm(cinfo, 1);
+
+       memset(&cmsg, 0, sizeof(cmsg));
+       cmsg.type = cpu_to_le32(METADATA_UPDATED);
+       rdev_for_each(rdev, mddev)
+               if (rdev->raid_disk >= 0 && !test_bit(Faulty, &rdev->flags)) {
+                       raid_slot = rdev->desc_nr;
+                       break;
+               }
+       if (raid_slot >= 0) {
+               cmsg.raid_slot = cpu_to_le32(raid_slot);
+               /*
+                * We can only change capiticy after all the nodes can do it,
+                * so need to wait after other nodes already received the msg
+                * and handled the change
+                */
+               ret = __sendmsg(cinfo, &cmsg);
+               if (ret) {
+                       pr_err("%s:%d: failed to send METADATA_UPDATED msg\n",
+                              __func__, __LINE__);
+                       unlock_comm(cinfo);
+                       return;
+               }
+       } else {
+               pr_err("md-cluster: No good device id found to send\n");
+               unlock_comm(cinfo);
+               return;
+       }
+
+       /*
+        * check the sync_size from other node's bitmap, if sync_size
+        * have already updated in other nodes as expected, send an
+        * empty metadata msg to permit the change of capacity
+        */
+       if (cluster_check_sync_size(mddev) == 0) {
+               memset(&cmsg, 0, sizeof(cmsg));
+               cmsg.type = cpu_to_le32(CHANGE_CAPACITY);
+               ret = __sendmsg(cinfo, &cmsg);
+               if (ret)
+                       pr_err("%s:%d: failed to send CHANGE_CAPACITY msg\n",
+                              __func__, __LINE__);
+               set_capacity(mddev->gendisk, mddev->array_sectors);
+               revalidate_disk(mddev->gendisk);
+       } else {
+               /* revert to previous sectors */
+               ret = mddev->pers->resize(mddev, old_dev_sectors);
+               if (!ret)
+                       revalidate_disk(mddev->gendisk);
+               ret = __sendmsg(cinfo, &cmsg);
+               if (ret)
+                       pr_err("%s:%d: failed to send METADATA_UPDATED msg\n",
+                              __func__, __LINE__);
+       }
+       unlock_comm(cinfo);
+}
+
 static int resync_start(struct mddev *mddev)
 {
        struct md_cluster_info *cinfo = mddev->cluster_info;
@@ -1396,6 +1471,7 @@ static struct md_cluster_operations cluster_ops = {
        .gather_bitmaps = gather_bitmaps,
        .lock_all_bitmaps = lock_all_bitmaps,
        .unlock_all_bitmaps = unlock_all_bitmaps,
+       .update_size = update_size,
 };
 
 static int __init cluster_init(void)

diff --git a/drivers/md/md-cluster.h b/drivers/md/md-cluster.h
index e765499ba59125b7ac4529e6805b1ea15582ab45..2740161779834c184e111fa08fc9404c3b63ec33 100644 (file)
--- a/drivers/md/md-cluster.h
+++ b/drivers/md/md-cluster.h
@@ -27,6 +27,7 @@ struct md_cluster_operations {
        int (*gather_bitmaps)(struct md_rdev *rdev);
        int (*lock_all_bitmaps)(struct mddev *mddev);
        void (*unlock_all_bitmaps)(struct mddev *mddev);
+       void (*update_size)(struct mddev *mddev, sector_t old_dev_sectors);
 };
 
 #endif /* _MD_CLUSTER_H */

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 83f325077dc85295f35eec0323604ea32942e8c2..72ef3f18ac9af6d5f624acd10421bd0afca3773b 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6493,10 +6493,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
        struct md_rdev *rdev;
        int rv;
        int fit = (num_sectors == 0);
-
-       /* cluster raid doesn't support update size */
-       if (mddev_is_clustered(mddev))
-               return -EINVAL;
+       sector_t old_dev_sectors = mddev->dev_sectors;
 
        if (mddev->pers->resize == NULL)
                return -EINVAL;
@@ -6525,7 +6522,9 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
        }
        rv = mddev->pers->resize(mddev, num_sectors);
        if (!rv) {
-               if (mddev->queue) {
+               if (mddev_is_clustered(mddev))
+                       md_cluster_ops->update_size(mddev, old_dev_sectors);
+               else if (mddev->queue) {
                        set_capacity(mddev->gendisk, mddev->array_sectors);
                        revalidate_disk(mddev->gendisk);
                }
@@ -8743,6 +8742,18 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
        int role, ret;
        char b[BDEVNAME_SIZE];
 
+       /*
+        * If size is changed in another node then we need to
+        * do resize as well.
+        */
+       if (mddev->dev_sectors != le64_to_cpu(sb->size)) {
+               ret = mddev->pers->resize(mddev, le64_to_cpu(sb->size));
+               if (ret)
+                       pr_info("md-cluster: resize failed\n");
+               else
+                       bitmap_update_sb(mddev->bitmap);
+       }
+
        /* Check for change of roles in the active devices */
        rdev_for_each(rdev2, mddev) {
                if (test_bit(Faulty, &rdev2->flags))