dm raid: ensure superblock's size matches device's logical block size (40d43c4b) · Commits · 戴 / test

The dm-raid superblock (struct dm_raid_superblock) is padded to 512 bytes and that size is being used to read it in from the metadata device into one preallocated page. Reading or writing this on a 512-byte sector device works fine but on a 4096-byte sector device this fails. Set the dm-raid superblock's size to the logical block size of the metadata device, because IO at that size is guaranteed too work. Also add a size check to avoid silent partial metadata loss in case the superblock should ever grow past the logical block size or PAGE_SIZE. [includes pointer math fix from Dan Carpenter] Reported-by:

"Liuhua Wang" <lwang@suse.com> Signed-off-by:

Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by:

Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org

drivers/md/dm-raid.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -789,8 +789,7 @@ struct dm_raid_superblock {
		__le32 layout;
		__le32 stripe_sectors;

		__u8 pad[452]; /* Round struct to 512 bytes. */
		/* Always set to 0 when writing. */
		/* Remainder of a logical block is zero-filled when writing (see super_sync()). */
		} __packed;

		static int read_disk_sb(struct md_rdev *rdev, int size)
		@@ -827,7 +826,7 @@ static void super_sync(struct mddev mddev, struct md_rdev rdev)
		test_bit(Faulty, &(rs->dev[i].rdev.flags)))
		failed_devices \|= (1ULL << i);

		memset(sb, 0, sizeof(*sb));
		memset(sb + 1, 0, rdev->sb_size - sizeof(*sb));

		sb->magic = cpu_to_le32(DM_RAID_MAGIC);
		sb->features = cpu_to_le32(0); /* No features yet */
		@@ -862,7 +861,11 @@ static int super_load(struct md_rdev rdev, struct md_rdev refdev)
		uint64_t events_sb, events_refsb;

		rdev->sb_start = 0;
		rdev->sb_size = sizeof(*sb);
		rdev->sb_size = bdev_logical_block_size(rdev->meta_bdev);
		if (rdev->sb_size < sizeof(*sb) \|\| rdev->sb_size > PAGE_SIZE) {
		DMERR("superblock size of a logical block is no longer valid");
		return -EINVAL;
		}

		ret = read_disk_sb(rdev, rdev->sb_size);
		if (ret)

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