Merge tag 'for-4.12/dm-fixes-5' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

- dm thinp fix for crash that will occur when metadata device failure
races with discard passdown to the underlying data device.

- dm raid fix to not access the superblock's >= 1.9.0 'sectors' member
unconditionally.

* tag 'for-4.12/dm-fixes-5' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm thin: do not queue freed thin mapping for next stage processing
dm raid: fix oops on upgrading to extended superblock format

drivers/md/dm-raid.c

···
 	/********************************************************************
 	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
 	 *
-	 * FEATURE_FLAG_SUPPORTS_V190 in the features member indicates that those exist
+	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
 	 */
 
 	__le32 flags; /* Flags defining array states for reshaping */
···
 	sb->layout = cpu_to_le32(mddev->layout);
 	sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
 
+	/********************************************************************
+	 * BELOW FOLLOW V1.9.0 EXTENSIONS TO THE PRISTINE SUPERBLOCK FORMAT!!!
+	 *
+	 * FEATURE_FLAG_SUPPORTS_V190 in the compat_features member indicates that those exist
+	 */
 	sb->new_level = cpu_to_le32(mddev->new_level);
 	sb->new_layout = cpu_to_le32(mddev->new_layout);
 	sb->new_stripe_sectors = cpu_to_le32(mddev->new_chunk_sectors);
···
 	mddev->bitmap_info.default_offset = mddev->bitmap_info.offset;
 
 	if (!test_and_clear_bit(FirstUse, &rdev->flags)) {
-		/* Retrieve device size stored in superblock to be prepared for shrink */
-		rdev->sectors = le64_to_cpu(sb->sectors);
+		/*
+		 * Retrieve rdev size stored in superblock to be prepared for shrink.
+		 * Check extended superblock members are present otherwise the size
+		 * will not be set!
+		 */
+		if (le32_to_cpu(sb->compat_features) & FEATURE_FLAG_SUPPORTS_V190)
+			rdev->sectors = le64_to_cpu(sb->sectors);
+
 		rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
 		if (rdev->recovery_offset == MaxSector)
 			set_bit(In_sync, &rdev->flags);

drivers/md/dm-thin.c

···
 		return;
 	}
 
+	/*
+	 * Increment the unmapped blocks.  This prevents a race between the
+	 * passdown io and reallocation of freed blocks.
+	 */
+	r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
+	if (r) {
+		metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
+		bio_io_error(m->bio);
+		cell_defer_no_holder(tc, m->cell);
+		mempool_free(m, pool->mapping_pool);
+		return;
+	}
+
 	discard_parent = bio_alloc(GFP_NOIO, 1);
 	if (!discard_parent) {
 		DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.",
···
 			r = issue_discard(&op, m->data_block, data_end);
 			end_discard(&op, r);
 		}
-	}
-
-	/*
-	 * Increment the unmapped blocks.  This prevents a race between the
-	 * passdown io and reallocation of freed blocks.
-	 */
-	r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end);
-	if (r) {
-		metadata_operation_failed(pool, "dm_pool_inc_data_range", r);
-		bio_io_error(m->bio);
-		cell_defer_no_holder(tc, m->cell);
-		mempool_free(m, pool->mapping_pool);
-		return;
 	}
 }