md: Skip cluster setup for dm-raid (d3b178ad) · Commits · 戴 / test

There is a bug that the bitmap superblock isn't initialised properly for dm-raid, so a new field can have garbage in new fields. (dm-raid does initialisation in the kernel - md initialised the superblock in mdadm). This means that for dm-raid we cannot currently trust the new ->nodes field. So: - use __GFP_ZERO to initialise the superblock properly for all new arrays - initialise all fields in bitmap_info in bitmap_new_disk_sb - ignore ->nodes for dm arrays (yes, this is a hack) This bug exposes dm-raid to bug in the (still experimental) md-cluster code, so it is suitable for -stable. It does cause crashes. References: https://bugzilla.kernel.org/show_bug.cgi?id=100491 Cc: stable@vger.kernel.org (v4.1) Signed-off-By:

Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by:

NeilBrown <neilb@suse.com>

drivers/md/bitmap.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -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);

		@@ -611,8 +612,16 @@ 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);
		/* 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);
		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))

Admin message