[PATCH] md: allow checkpoint of recovery with version-1 superblock

For a while we have had checkpointing of resync.  The version-1 superblock
allows recovery to be checkpointed as well, and this patch implements that.

Due to early carelessness we need to add a feature flag to signal that the
recovery_offset field is in use, otherwise older kernels would assume that a
partially recovered array is in fact fully recovered.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 94 insertions, 21 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 71d46eb2c438..a296edd7e1c3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1175,7 +1175,11 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                         set_bit(Faulty, &rdev->flags);
                         break;
                 default:
-                        set_bit(In_sync, &rdev->flags);
+                        if ((le32_to_cpu(sb->feature_map) &
+                             MD_FEATURE_RECOVERY_OFFSET))
+                                rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
+                        else
+                                set_bit(In_sync, &rdev->flags);
                         rdev->raid_disk = role;
                         break;
                 }
@@ -1199,6 +1203,7 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
 
         sb->feature_map = 0;
         sb->pad0 = 0;
+        sb->recovery_offset = cpu_to_le64(0);
         memset(sb->pad1, 0, sizeof(sb->pad1));
         memset(sb->pad2, 0, sizeof(sb->pad2));
         memset(sb->pad3, 0, sizeof(sb->pad3));
@@ -1219,6 +1224,14 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
                 sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
                 sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
         }
+
+        if (rdev->raid_disk >= 0 &&
+            !test_bit(In_sync, &rdev->flags) &&
+            rdev->recovery_offset > 0) {
+                sb->feature_map |= cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
+                sb->recovery_offset = cpu_to_le64(rdev->recovery_offset);
+        }
+
         if (mddev->reshape_position != MaxSector) {
                 sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
                 sb->reshape_position = cpu_to_le64(mddev->reshape_position);
@@ -1243,11 +1256,12 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
                         sb->dev_roles[i] = cpu_to_le16(0xfffe);
                 else if (test_bit(In_sync, &rdev2->flags))
                         sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
+                else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
+                        sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
                 else
                         sb->dev_roles[i] = cpu_to_le16(0xffff);
         }
 
-        sb->recovery_offset = cpu_to_le64(0); /* not supported yet */
         sb->sb_csum = calc_sb_1_csum(sb);
 }
 
@@ -2603,8 +2617,6 @@ static struct kobject *md_probe(dev_t dev, int *part, void *data)
         return NULL;
 }
 
-void md_wakeup_thread(mdk_thread_t *thread);
-
 static void md_safemode_timeout(unsigned long data)
 {
         mddev_t *mddev = (mddev_t *) data;
@@ -2786,6 +2798,36 @@ static int do_md_run(mddev_t * mddev)
         mddev->queue->queuedata = mddev;
         mddev->queue->make_request_fn = mddev->pers->make_request;
 
+        /* If there is a partially-recovered drive we need to
+         * start recovery here.  If we leave it to md_check_recovery,
+         * it will remove the drives and not do the right thing
+         */
+        if (mddev->degraded) {
+                struct list_head *rtmp;
+                int spares = 0;
+                ITERATE_RDEV(mddev,rdev,rtmp)
+                        if (rdev->raid_disk >= 0 &&
+                            !test_bit(In_sync, &rdev->flags) &&
+                            !test_bit(Faulty, &rdev->flags))
+                                /* complete an interrupted recovery */
+                                spares++;
+                if (spares && mddev->pers->sync_request) {
+                        mddev->recovery = 0;
+                        set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+                        mddev->sync_thread = md_register_thread(md_do_sync,
+                                                                mddev,
+                                                                "%s_resync");
+                        if (!mddev->sync_thread) {
+                                printk(KERN_ERR "%s: could not start resync"
+                                       " thread...\n",
+                                       mdname(mddev));
+                                /* leave the spares where they are, it shouldn't hurt */
+                                mddev->recovery = 0;
+                        } else
+                                md_wakeup_thread(mddev->sync_thread);
+                }
+        }
+
         mddev->changed = 1;
         md_new_event(mddev);
         return 0;
@@ -2819,6 +2861,7 @@ static int restart_array(mddev_t *mddev)
                  */
                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
                 md_wakeup_thread(mddev->thread);
+                md_wakeup_thread(mddev->sync_thread);
                 err = 0;
         } else {
                 printk(KERN_ERR "md: %s has no personality assigned.\n",
@@ -2842,6 +2885,7 @@ static int do_md_stop(mddev_t * mddev, int ro)
                 }
 
                 if (mddev->sync_thread) {
+                        set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
                         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
                         md_unregister_thread(mddev->sync_thread);
                         mddev->sync_thread = NULL;
@@ -2871,13 +2915,14 @@ static int do_md_stop(mddev_t * mddev, int ro)
                         if (mddev->ro)
                                 mddev->ro = 0;
                 }
-                if (!mddev->in_sync) {
+                if (!mddev->in_sync || mddev->sb_dirty) {
                         /* mark array as shutdown cleanly */
                         mddev->in_sync = 1;
                         md_update_sb(mddev);
                 }
                 if (ro)
                         set_disk_ro(disk, 1);
+                clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
         }
 
         /*
@@ -4665,10 +4710,14 @@ void md_do_sync(mddev_t *mddev)
         struct list_head *tmp;
         sector_t last_check;
         int skipped = 0;
+        struct list_head *rtmp;
+        mdk_rdev_t *rdev;
 
         /* just incase thread restarts... */
         if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
                 return;
+        if (mddev->ro) /* never try to sync a read-only array */
+                return;
 
         /* we overload curr_resync somewhat here.
          * 0 == not engaged in resync at all
@@ -4727,17 +4776,30 @@ void md_do_sync(mddev_t *mddev)
                 }
         } while (mddev->curr_resync < 2);
 
+        j = 0;
         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
                 /* resync follows the size requested by the personality,
                  * which defaults to physical size, but can be virtual size
                  */
                 max_sectors = mddev->resync_max_sectors;
                 mddev->resync_mismatches = 0;
+                /* we don't use the checkpoint if there's a bitmap */
+                if (!mddev->bitmap &&
+                    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+                        j = mddev->recovery_cp;
         } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
                 max_sectors = mddev->size << 1;
-        else
+        else {
                 /* recovery follows the physical size of devices */
                 max_sectors = mddev->size << 1;
+                j = MaxSector;
+                ITERATE_RDEV(mddev,rdev,rtmp)
+                        if (rdev->raid_disk >= 0 &&
+                            !test_bit(Faulty, &rdev->flags) &&
+                            !test_bit(In_sync, &rdev->flags) &&
+                            rdev->recovery_offset < j)
+                                j = rdev->recovery_offset;
+        }
 
         printk(KERN_INFO "md: syncing RAID array %s\n", mdname(mddev));
         printk(KERN_INFO "md: minimum _guaranteed_ reconstruction speed:"
@@ -4747,12 +4809,7 @@ void md_do_sync(mddev_t *mddev)
                speed_max(mddev));
 
         is_mddev_idle(mddev); /* this also initializes IO event counters */
-        /* we don't use the checkpoint if there's a bitmap */
-        if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && !mddev->bitmap
-            && ! test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
-                j = mddev->recovery_cp;
-        else
-                j = 0;
+
         io_sectors = 0;
         for (m = 0; m < SYNC_MARKS; m++) {
                 mark[m] = jiffies;
@@ -4873,15 +4930,28 @@ void md_do_sync(mddev_t *mddev)
         if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&
             test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
             !test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
-            mddev->curr_resync > 2 &&
-            mddev->curr_resync >= mddev->recovery_cp) {
-                if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
-                        printk(KERN_INFO 
-                                "md: checkpointing recovery of %s.\n",
-                                mdname(mddev));
-                        mddev->recovery_cp = mddev->curr_resync;
-                } else
-                        mddev->recovery_cp = MaxSector;
+            mddev->curr_resync > 2) {
+                if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+                        if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
+                                if (mddev->curr_resync >= mddev->recovery_cp) {
+                                        printk(KERN_INFO
+                                               "md: checkpointing recovery of %s.\n",
+                                               mdname(mddev));
+                                        mddev->recovery_cp = mddev->curr_resync;
+                                }
+                        } else
+                                mddev->recovery_cp = MaxSector;
+                } else {
+                        if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+                                mddev->curr_resync = MaxSector;
+                        ITERATE_RDEV(mddev,rdev,rtmp)
+                                if (rdev->raid_disk >= 0 &&
+                                    !test_bit(Faulty, &rdev->flags) &&
+                                    !test_bit(In_sync, &rdev->flags) &&
+                                    rdev->recovery_offset < mddev->curr_resync)
+                                        rdev->recovery_offset = mddev->curr_resync;
+                        mddev->sb_dirty = 1;
+                }
         }
 
  skip:
@@ -5002,6 +5072,8 @@ void md_check_recovery(mddev_t *mddev)
                 clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
                 clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 
+                if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
+                        goto unlock;
                 /* no recovery is running.
                  * remove any failed drives, then
                  * add spares if possible.
@@ -5024,6 +5096,7 @@ void md_check_recovery(mddev_t *mddev)
                         ITERATE_RDEV(mddev,rdev,rtmp)
                                 if (rdev->raid_disk < 0
                                     && !test_bit(Faulty, &rdev->flags)) {
+                                        rdev->recovery_offset = 0;
                                         if (mddev->pers->hot_add_disk(mddev,rdev)) {
                                                 char nm[20];
                                                 sprintf(nm, "rd%d", rdev->raid_disk);