From: Heinz Mauelshagen Date: Fri, 17 Oct 2014 11:38:50 +0000 (+0200) Subject: dm raid: ensure superblock's size matches device's logical block size X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=40d43c4b4cac4c2647bf07110d7b07d35f399a84;p=linux-beck.git dm raid: ensure superblock's size matches device's logical block size 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" Signed-off-by: Heinz Mauelshagen Signed-off-by: Dan Carpenter Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 4857fa4a5484..a7cb9dd5f135 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -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 PAGE_SIZE) { + DMERR("superblock size of a logical block is no longer valid"); + return -EINVAL; + } ret = read_disk_sb(rdev, rdev-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)