Merge tag 'md-3.8-fixes' of git://neil.brown.name/md

Pull dmraid fix from NeilBrown:
 "Just one fix for md in 3.8

  dmraid assess redundancy and replacements slightly inaccurately which
  could lead to some degraded arrays failing to assemble."

* tag 'md-3.8-fixes' of git://neil.brown.name/md:
  DM-RAID: Fix RAID10's check for sufficient redundancy

1 files changed, 37 insertions, 64 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 3d8984edeff7..9e58dbd8d8cb 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -340,24 +340,22 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 }
 
 /*
- * validate_rebuild_devices
+ * validate_raid_redundancy
  * @rs
  *
- * Determine if the devices specified for rebuild can result in a valid
- * usable array that is capable of rebuilding the given devices.
+ * Determine if there are enough devices in the array that haven't
+ * failed (or are being rebuilt) to form a usable array.
  *
  * Returns: 0 on success, -EINVAL on failure.
  */
-static int validate_rebuild_devices(struct raid_set *rs)
+static int validate_raid_redundancy(struct raid_set *rs)
 {
         unsigned i, rebuild_cnt = 0;
         unsigned rebuilds_per_group, copies, d;
 
-        if (!(rs->print_flags & DMPF_REBUILD))
-                return 0;
-
         for (i = 0; i < rs->md.raid_disks; i++)
-                if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
+                if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
+                    !rs->dev[i].rdev.sb_page)
                         rebuild_cnt++;
 
         switch (rs->raid_type->level) {
@@ -393,27 +391,24 @@ static int validate_rebuild_devices(struct raid_set *rs)
                  *          A    A    B    B    C
                  *          C    D    D    E    E
                  */
-                rebuilds_per_group = 0;
                 for (i = 0; i < rs->md.raid_disks * copies; i++) {
+                        if (!(i % copies))
+                                rebuilds_per_group = 0;
                         d = i % rs->md.raid_disks;
-                        if (!test_bit(In_sync, &rs->dev[d].rdev.flags) &&
+                        if ((!rs->dev[d].rdev.sb_page ||
+                             !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
                             (++rebuilds_per_group >= copies))
                                 goto too_many;
-                        if (!((i + 1) % copies))
-                                rebuilds_per_group = 0;
                 }
                 break;
         default:
-                DMERR("The rebuild parameter is not supported for %s",
-                      rs->raid_type->name);
-                rs->ti->error = "Rebuild not supported for this RAID type";
-                return -EINVAL;
+                if (rebuild_cnt)
+                        return -EINVAL;
         }
 
         return 0;
 
 too_many:
-        rs->ti->error = "Too many rebuild devices specified";
         return -EINVAL;
 }
 
@@ -664,9 +659,6 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
         }
         rs->md.dev_sectors = sectors_per_dev;
 
-        if (validate_rebuild_devices(rs))
-                return -EINVAL;
-
         /* Assume there are no metadata devices until the drives are parsed */
         rs->md.persistent = 0;
         rs->md.external = 1;
@@ -995,28 +987,10 @@ static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 {
         int ret;
-        unsigned redundancy = 0;
         struct raid_dev *dev;
         struct md_rdev *rdev, *tmp, *freshest;
         struct mddev *mddev = &rs->md;
 
-        switch (rs->raid_type->level) {
-        case 1:
-                redundancy = rs->md.raid_disks - 1;
-                break;
-        case 4:
-        case 5:
-        case 6:
-                redundancy = rs->raid_type->parity_devs;
-                break;
-        case 10:
-                redundancy = raid10_md_layout_to_copies(mddev->layout) - 1;
-                break;
-        default:
-                ti->error = "Unknown RAID type";
-                return -EINVAL;
-        }
-
         freshest = NULL;
         rdev_for_each_safe(rdev, tmp, mddev) {
                 /*
@@ -1045,44 +1019,43 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
                         break;
                 default:
                         dev = container_of(rdev, struct raid_dev, rdev);
-                        if (redundancy--) {
-                                if (dev->meta_dev)
-                                        dm_put_device(ti, dev->meta_dev);
-
-                                dev->meta_dev = NULL;
-                                rdev->meta_bdev = NULL;
+                        if (dev->meta_dev)
+                                dm_put_device(ti, dev->meta_dev);
 
-                                if (rdev->sb_page)
-                                        put_page(rdev->sb_page);
+                        dev->meta_dev = NULL;
+                        rdev->meta_bdev = NULL;
 
-                                rdev->sb_page = NULL;
+                        if (rdev->sb_page)
+                                put_page(rdev->sb_page);
 
-                                rdev->sb_loaded = 0;
+                        rdev->sb_page = NULL;
 
-                                /*
-                                 * We might be able to salvage the data device
-                                 * even though the meta device has failed.  For
-                                 * now, we behave as though '- -' had been
-                                 * set for this device in the table.
-                                 */
-                                if (dev->data_dev)
-                                        dm_put_device(ti, dev->data_dev);
+                        rdev->sb_loaded = 0;
 
-                                dev->data_dev = NULL;
-                                rdev->bdev = NULL;
+                        /*
+                         * We might be able to salvage the data device
+                         * even though the meta device has failed.  For
+                         * now, we behave as though '- -' had been
+                         * set for this device in the table.
+                         */
+                        if (dev->data_dev)
+                                dm_put_device(ti, dev->data_dev);
 
-                                list_del(&rdev->same_set);
+                        dev->data_dev = NULL;
+                        rdev->bdev = NULL;
 
-                                continue;
-                        }
-                        ti->error = "Failed to load superblock";
-                        return ret;
+                        list_del(&rdev->same_set);
                 }
         }
 
         if (!freshest)
                 return 0;
 
+        if (validate_raid_redundancy(rs)) {
+                rs->ti->error = "Insufficient redundancy to activate array";
+                return -EINVAL;
+        }
+
         /*
          * Validation of the freshest device provides the source of
          * validation for the remaining devices.
@@ -1432,7 +1405,7 @@ static void raid_resume(struct dm_target *ti)
 
 static struct target_type raid_target = {
         .name = "raid",
-        .version = {1, 4, 0},
+        .version = {1, 4, 1},
         .module = THIS_MODULE,
         .ctr = raid_ctr,
         .dtr = raid_dtr,