1 files changed, 17 insertions, 11 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index ed2346ddf4c9..e51de52eeb94 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -494,7 +494,7 @@ static int bitmap_new_disk_sb(struct bitmap *bitmap)
         bitmap_super_t *sb;
         unsigned long chunksize, daemon_sleep, write_behind;
 
-        bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
+        bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
         if (bitmap->storage.sb_page == NULL)
                 return -ENOMEM;
         bitmap->storage.sb_page->index = 0;
@@ -541,6 +541,7 @@ static int bitmap_new_disk_sb(struct bitmap *bitmap)
         sb->state = cpu_to_le32(bitmap->flags);
         bitmap->events_cleared = bitmap->mddev->events;
         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
+        bitmap->mddev->bitmap_info.nodes = 0;
 
         kunmap_atomic(sb);
 
@@ -558,6 +559,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
         unsigned long sectors_reserved = 0;
         int err = -EINVAL;
         struct page *sb_page;
+        loff_t offset = bitmap->mddev->bitmap_info.offset;
 
         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
                 chunksize = 128 * 1024 * 1024;
@@ -584,9 +586,9 @@ re_read:
                 bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
                 /* to 4k blocks */
                 bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
-                bitmap->mddev->bitmap_info.offset += bitmap->cluster_slot * (bm_blocks << 3);
+                offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
                 pr_info("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
-                        bitmap->cluster_slot, (unsigned long long)bitmap->mddev->bitmap_info.offset);
+                        bitmap->cluster_slot, offset);
         }
 
         if (bitmap->storage.file) {
@@ -597,7 +599,7 @@ re_read:
                                 bitmap, bytes, sb_page);
         } else {
                 err = read_sb_page(bitmap->mddev,
-                                   bitmap->mddev->bitmap_info.offset,
+                                   offset,
                                    sb_page,
                                    0, sizeof(bitmap_super_t));
         }
@@ -611,8 +613,16 @@ re_read:
         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
         write_behind = le32_to_cpu(sb->write_behind);
         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
-        nodes = le32_to_cpu(sb->nodes);
-        strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
+        /* XXX: This is a hack to ensure that we don't use clustering
+         *  in case:
+         *      - dm-raid is in use and
+         *      - the nodes written in bitmap_sb is erroneous.
+         */
+        if (!bitmap->mddev->sync_super) {
+                nodes = le32_to_cpu(sb->nodes);
+                strlcpy(bitmap->mddev->bitmap_info.cluster_name,
+                                sb->cluster_name, 64);
+        }
 
         /* verify that the bitmap-specific fields are valid */
         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
@@ -671,7 +681,7 @@ out:
         kunmap_atomic(sb);
         /* Assiging chunksize is required for "re_read" */
         bitmap->mddev->bitmap_info.chunksize = chunksize;
-        if (nodes && (bitmap->cluster_slot < 0)) {
+        if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
                 err = md_setup_cluster(bitmap->mddev, nodes);
                 if (err) {
                         pr_err("%s: Could not setup cluster service (%d)\n",
@@ -1866,10 +1876,6 @@ int bitmap_copy_from_slot(struct mddev *mddev, int slot,
         if (IS_ERR(bitmap))
                 return PTR_ERR(bitmap);
 
-        rv = bitmap_read_sb(bitmap);
-        if (rv)
-                goto err;
-
         rv = bitmap_init_from_disk(bitmap, 0);
         if (rv)
                 goto err;