dm zoned: allocate temporary superblock for tertiary devices

Checking the tertiary superblock just consists of validating UUIDs,
crcs, and the generation number; it doesn't have contents which would
be required during the actual operation.

So allocate a temporary superblock when checking tertiary devices to
avoid having to store it together with the 'real' superblocks.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index b235283a88460ddeef447f2305a71d918f399a29..525ac0d8028703a10faf66a97335596a19cbdf8c 100644 (file)
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -174,7 +174,7 @@ struct dmz_metadata {
        /* Zone information array */
        struct xarray           zones;
 
-       struct dmz_sb           sb[3];
+       struct dmz_sb           sb[2];
        unsigned int            mblk_primary;
        unsigned int            sb_version;
        u64                     sb_gen;
@@ -1016,10 +1016,11 @@ err:
 /*
  * Check super block.
  */
-static int dmz_check_sb(struct dmz_metadata *zmd, unsigned int set)
+static int dmz_check_sb(struct dmz_metadata *zmd, struct dmz_sb *dsb,
+                       bool tertiary)
 {
-       struct dmz_super *sb = zmd->sb[set].sb;
-       struct dmz_dev *dev = zmd->sb[set].dev;
+       struct dmz_super *sb = dsb->sb;
+       struct dmz_dev *dev = dsb->dev;
        unsigned int nr_meta_zones, nr_data_zones;
        u32 crc, stored_crc;
        u64 gen;
@@ -1036,7 +1037,7 @@ static int dmz_check_sb(struct dmz_metadata *zmd, unsigned int set)
                            DMZ_META_VER, zmd->sb_version);
                return -EINVAL;
        }
-       if ((zmd->sb_version < 1) && (set == 2)) {
+       if (zmd->sb_version < 2 && tertiary) {
                dmz_dev_err(dev, "Tertiary superblocks are not supported");
                return -EINVAL;
        }
@@ -1080,7 +1081,7 @@ static int dmz_check_sb(struct dmz_metadata *zmd, unsigned int set)
                        return -ENXIO;
                }
 
-               if (set == 2) {
+               if (tertiary) {
                        /*
                         * Generation number should be 0, but it doesn't
                         * really matter if it isn't.
@@ -1129,14 +1130,13 @@ static int dmz_check_sb(struct dmz_metadata *zmd, unsigned int set)
 /*
  * Read the first or second super block from disk.
  */
-static int dmz_read_sb(struct dmz_metadata *zmd, unsigned int set)
+static int dmz_read_sb(struct dmz_metadata *zmd, struct dmz_sb *sb, int set)
 {
        dmz_zmd_debug(zmd, "read superblock set %d dev %s block %llu",
-                     set, zmd->sb[set].dev->name,
-                     zmd->sb[set].block);
+                     set, sb->dev->name, sb->block);
 
-       return dmz_rdwr_block(zmd->sb[set].dev, REQ_OP_READ,
-                             zmd->sb[set].block, zmd->sb[set].mblk->page);
+       return dmz_rdwr_block(sb->dev, REQ_OP_READ,
+                             sb->block, sb->mblk->page);
 }
 
 /*
@@ -1164,7 +1164,7 @@ static int dmz_lookup_secondary_sb(struct dmz_metadata *zmd)
        zmd->sb[1].zone = dmz_get(zmd, zone_id + 1);
        zmd->sb[1].dev = zmd->sb[0].dev;
        for (i = 1; i < zmd->nr_rnd_zones; i++) {
-               if (dmz_read_sb(zmd, 1) != 0)
+               if (dmz_read_sb(zmd, &zmd->sb[1], 1) != 0)
                        break;
                if (le32_to_cpu(zmd->sb[1].sb->magic) == DMZ_MAGIC)
                        return 0;
@@ -1181,9 +1181,9 @@ static int dmz_lookup_secondary_sb(struct dmz_metadata *zmd)
 }
 
 /*
- * Read the first or second super block from disk.
+ * Read a super block from disk.
  */
-static int dmz_get_sb(struct dmz_metadata *zmd, unsigned int set)
+static int dmz_get_sb(struct dmz_metadata *zmd, struct dmz_sb *sb, int set)
 {
        struct dmz_mblock *mblk;
        int ret;
@@ -1193,14 +1193,14 @@ static int dmz_get_sb(struct dmz_metadata *zmd, unsigned int set)
        if (!mblk)
                return -ENOMEM;
 
-       zmd->sb[set].mblk = mblk;
-       zmd->sb[set].sb = mblk->data;
+       sb->mblk = mblk;
+       sb->sb = mblk->data;
 
        /* Read super block */
-       ret = dmz_read_sb(zmd, set);
+       ret = dmz_read_sb(zmd, sb, set);
        if (ret) {
                dmz_free_mblock(zmd, mblk);
-               zmd->sb[set].mblk = NULL;
+               sb->mblk = NULL;
                return ret;
        }
 
@@ -1274,13 +1274,13 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
        /* Read and check the primary super block */
        zmd->sb[0].block = dmz_start_block(zmd, zmd->sb[0].zone);
        zmd->sb[0].dev = dmz_zone_to_dev(zmd, zmd->sb[0].zone);
-       ret = dmz_get_sb(zmd, 0);
+       ret = dmz_get_sb(zmd, &zmd->sb[0], 0);
        if (ret) {
                dmz_dev_err(zmd->sb[0].dev, "Read primary super block failed");
                return ret;
        }
 
-       ret = dmz_check_sb(zmd, 0);
+       ret = dmz_check_sb(zmd, &zmd->sb[0], false);
 
        /* Read and check secondary super block */
        if (ret == 0) {
@@ -1293,7 +1293,7 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
                }
                zmd->sb[1].block = dmz_start_block(zmd, zmd->sb[1].zone);
                zmd->sb[1].dev = zmd->sb[0].dev;
-               ret = dmz_get_sb(zmd, 1);
+               ret = dmz_get_sb(zmd, &zmd->sb[1], 1);
        } else
                ret = dmz_lookup_secondary_sb(zmd);
 
@@ -1302,7 +1302,7 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
                return ret;
        }
 
-       ret = dmz_check_sb(zmd, 1);
+       ret = dmz_check_sb(zmd, &zmd->sb[1], false);
        if (ret == 0)
                sb_good[1] = true;
 
@@ -1347,20 +1347,40 @@ static int dmz_load_sb(struct dmz_metadata *zmd)
                      "Using super block %u (gen %llu)",
                      zmd->mblk_primary, zmd->sb_gen);
 
-       if ((zmd->sb_version > 1) && zmd->sb[2].zone) {
-               zmd->sb[2].block = dmz_start_block(zmd, zmd->sb[2].zone);
-               zmd->sb[2].dev = dmz_zone_to_dev(zmd, zmd->sb[2].zone);
-               ret = dmz_get_sb(zmd, 2);
-               if (ret) {
-                       dmz_dev_err(zmd->sb[2].dev,
-                                   "Read tertiary super block failed");
-                       return ret;
+       if (zmd->sb_version > 1) {
+               int i;
+               struct dmz_sb *sb;
+
+               sb = kzalloc(sizeof(struct dmz_sb), GFP_KERNEL);
+               if (!sb)
+                       return -ENOMEM;
+               for (i = 1; i < zmd->nr_devs; i++) {
+                       sb->block = 0;
+                       sb->zone = dmz_get(zmd, zmd->dev[i].zone_offset);
+                       sb->dev = &zmd->dev[i];
+                       if (!dmz_is_meta(sb->zone)) {
+                               dmz_dev_err(sb->dev,
+                                           "Tertiary super block zone %u not marked as metadata zone",
+                                           sb->zone->id);
+                               ret = -EINVAL;
+                               goto out_kfree;
+                       }
+                       ret = dmz_get_sb(zmd, sb, i + 1);
+                       if (ret) {
+                               dmz_dev_err(sb->dev,
+                                           "Read tertiary super block failed");
+                               dmz_free_mblock(zmd, sb->mblk);
+                               goto out_kfree;
+                       }
+                       ret = dmz_check_sb(zmd, sb, true);
+                       dmz_free_mblock(zmd, sb->mblk);
+                       if (ret == -EINVAL)
+                               goto out_kfree;
                }
-               ret = dmz_check_sb(zmd, 2);
-               if (ret == -EINVAL)
-                       return ret;
+       out_kfree:
+               kfree(sb);
        }
-       return 0;
+       return ret;
 }
 
 /*
@@ -1417,12 +1437,15 @@ static int dmz_init_zone(struct blk_zone *blkz, unsigned int num, void *data)
                                zmd->sb[0].zone = zone;
                        }
                }
-               if (zmd->nr_devs > 1 && !zmd->sb[2].zone) {
-                       /* Tertiary superblock zone */
-                       zmd->sb[2].zone = zone;
+               if (zmd->nr_devs > 1 && num == 0) {
+                       /*
+                        * Tertiary superblock zones are always at the
+                        * start of the zoned devices, so mark them
+                        * as metadata zone.
+                        */
+                       set_bit(DMZ_META, &zone->flags);
                }
        }
-
        return 0;
 }
 
@@ -2860,16 +2883,6 @@ int dmz_ctr_metadata(struct dmz_dev *dev, int num_dev,
                }
                set_bit(DMZ_META, &zone->flags);
        }
-       if (zmd->sb[2].zone) {
-               zone = dmz_get(zmd, zmd->sb[2].zone->id);
-               if (!zone) {
-                       dmz_zmd_err(zmd,
-                                   "Tertiary metadata zone not present");
-                       ret = -ENXIO;
-                       goto err;
-               }
-               set_bit(DMZ_META, &zone->flags);
-       }
        /* Load mapping table */
        ret = dmz_load_mapping(zmd);
        if (ret)