1 files changed, 107 insertions, 24 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 6b956fc04dc..e55271d6e7f 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2968,6 +2968,86 @@ err:
 	return -EINVAL;
 }
 
+static int check_offsets_and_sizes(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
+{
+	sector_t capacity = drbd_get_capacity(bdev->md_bdev);
+	struct drbd_md *in_core = &bdev->md;
+	s32 on_disk_al_sect;
+	s32 on_disk_bm_sect;
+
+	/* The on-disk size of the activity log, calculated from offsets, and
+	 * the size of the activity log calculated from the stripe settings,
+	 * should match.
+	 * Though we could relax this a bit: it is ok, if the striped activity log
+	 * fits in the available on-disk activity log size.
+	 * Right now, that would break how resize is implemented.
+	 * TODO: make drbd_determine_dev_size() (and the drbdmeta tool) aware
+	 * of possible unused padding space in the on disk layout. */
+	if (in_core->al_offset < 0) {
+		if (in_core->bm_offset > in_core->al_offset)
+			goto err;
+		on_disk_al_sect = -in_core->al_offset;
+		on_disk_bm_sect = in_core->al_offset - in_core->bm_offset;
+	} else {
+		if (in_core->al_offset != MD_4kB_SECT)
+			goto err;
+		if (in_core->bm_offset < in_core->al_offset + in_core->al_size_4k * MD_4kB_SECT)
+			goto err;
+
+		on_disk_al_sect = in_core->bm_offset - MD_4kB_SECT;
+		on_disk_bm_sect = in_core->md_size_sect - in_core->bm_offset;
+	}
+
+	/* old fixed size meta data is exactly that: fixed. */
+	if (in_core->meta_dev_idx >= 0) {
+		if (in_core->md_size_sect != MD_128MB_SECT
+		||  in_core->al_offset != MD_4kB_SECT
+		||  in_core->bm_offset != MD_4kB_SECT + MD_32kB_SECT
+		||  in_core->al_stripes != 1
+		||  in_core->al_stripe_size_4k != MD_32kB_SECT/8)
+			goto err;
+	}
+
+	if (capacity < in_core->md_size_sect)
+		goto err;
+	if (capacity - in_core->md_size_sect < drbd_md_first_sector(bdev))
+		goto err;
+
+	/* should be aligned, and at least 32k */
+	if ((on_disk_al_sect & 7) || (on_disk_al_sect < MD_32kB_SECT))
+		goto err;
+
+	/* should fit (for now: exactly) into the available on-disk space;
+	 * overflow prevention is in check_activity_log_stripe_size() above. */
+	if (on_disk_al_sect != in_core->al_size_4k * MD_4kB_SECT)
+		goto err;
+
+	/* again, should be aligned */
+	if (in_core->bm_offset & 7)
+		goto err;
+
+	/* FIXME check for device grow with flex external meta data? */
+
+	/* can the available bitmap space cover the last agreed device size? */
+	if (on_disk_bm_sect < (in_core->la_size_sect+7)/MD_4kB_SECT/8/512)
+		goto err;
+
+	return 0;
+
+err:
+	dev_err(DEV, "meta data offsets don't make sense: idx=%d "
+			"al_s=%u, al_sz4k=%u, al_offset=%d, bm_offset=%d, "
+			"md_size_sect=%u, la_size=%llu, md_capacity=%llu\n",
+			in_core->meta_dev_idx,
+			in_core->al_stripes, in_core->al_stripe_size_4k,
+			in_core->al_offset, in_core->bm_offset, in_core->md_size_sect,
+			(unsigned long long)in_core->la_size_sect,
+			(unsigned long long)capacity);
+
+	return -EINVAL;
+}
+
+
 /**
  * drbd_md_read() - Reads in the meta data super block
  * @mdev:	DRBD device.
@@ -2976,7 +3056,8 @@ err:
  * Return NO_ERROR on success, and an enum drbd_ret_code in case
  * something goes wrong.
  *
- * Called exactly once during drbd_adm_attach()
+ * Called exactly once during drbd_adm_attach(), while still being D_DISKLESS,
+ * even before @bdev is assigned to @mdev->ldev.
  */
 int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 {
@@ -2984,14 +3065,15 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 	u32 magic, flags;
 	int i, rv = NO_ERROR;
 
-	if (!get_ldev_if_state(mdev, D_ATTACHING))
-		return ERR_IO_MD_DISK;
+	if (mdev->state.disk != D_DISKLESS)
+		return ERR_DISK_CONFIGURED;
 
 	buffer = drbd_md_get_buffer(mdev);
 	if (!buffer)
-		goto out;
+		return ERR_NOMEM;
 
-	/* First, figure out where our meta data superblock is located. */
+	/* First, figure out where our meta data superblock is located,
+	 * and read it. */
 	bdev->md.meta_dev_idx = bdev->disk_conf->meta_dev_idx;
 	bdev->md.md_offset = drbd_md_ss(bdev);
 
@@ -3022,14 +3104,29 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 		goto err;
 	}
 
-	if (check_activity_log_stripe_size(mdev, buffer, &bdev->md))
+	if (be32_to_cpu(buffer->bm_bytes_per_bit) != BM_BLOCK_SIZE) {
+		dev_err(DEV, "unexpected bm_bytes_per_bit: %u (expected %u)\n",
+		    be32_to_cpu(buffer->bm_bytes_per_bit), BM_BLOCK_SIZE);
 		goto err;
+	}
 
-	if (be32_to_cpu(buffer->al_offset) != bdev->md.al_offset) {
-		dev_err(DEV, "unexpected al_offset: %d (expected %d)\n",
-		    be32_to_cpu(buffer->al_offset), bdev->md.al_offset);
+
+	/* convert to in_core endian */
+	bdev->md.la_size_sect = be64_to_cpu(buffer->la_size_sect);
+	for (i = UI_CURRENT; i < UI_SIZE; i++)
+		bdev->md.uuid[i] = be64_to_cpu(buffer->uuid[i]);
+	bdev->md.flags = be32_to_cpu(buffer->flags);
+	bdev->md.device_uuid = be64_to_cpu(buffer->device_uuid);
+
+	bdev->md.md_size_sect = be32_to_cpu(buffer->md_size_sect);
+	bdev->md.al_offset = be32_to_cpu(buffer->al_offset);
+	bdev->md.bm_offset = be32_to_cpu(buffer->bm_offset);
+
+	if (check_activity_log_stripe_size(mdev, buffer, &bdev->md))
 		goto err;
-	}
+	if (check_offsets_and_sizes(mdev, bdev))
+		goto err;
+
 	if (be32_to_cpu(buffer->bm_offset) != bdev->md.bm_offset) {
 		dev_err(DEV, "unexpected bm_offset: %d (expected %d)\n",
 		    be32_to_cpu(buffer->bm_offset), bdev->md.bm_offset);
@@ -3041,20 +3138,8 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 		goto err;
 	}
 
-	if (be32_to_cpu(buffer->bm_bytes_per_bit) != BM_BLOCK_SIZE) {
-		dev_err(DEV, "unexpected bm_bytes_per_bit: %u (expected %u)\n",
-		    be32_to_cpu(buffer->bm_bytes_per_bit), BM_BLOCK_SIZE);
-		goto err;
-	}
-
 	rv = NO_ERROR;
 
-	bdev->md.la_size_sect = be64_to_cpu(buffer->la_size_sect);
-	for (i = UI_CURRENT; i < UI_SIZE; i++)
-		bdev->md.uuid[i] = be64_to_cpu(buffer->uuid[i]);
-	bdev->md.flags = be32_to_cpu(buffer->flags);
-	bdev->md.device_uuid = be64_to_cpu(buffer->device_uuid);
-
 	spin_lock_irq(&mdev->tconn->req_lock);
 	if (mdev->state.conn < C_CONNECTED) {
 		unsigned int peer;
@@ -3066,8 +3151,6 @@ int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 
  err:
 	drbd_md_put_buffer(mdev);
- out:
-	put_ldev(mdev);
 
 	return rv;
 }