[dm-devel] [PATCH 1/4] dm: Fix mapping zone alignment check

[Damien Le Moal]

In device_area_is_invalid(), check a device mapping zone alignment
before checking the LBA size so that the check is also performed for
devices with a single sector (512B) LBA size.

Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
---
 drivers/md/dm-table.c | 51 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index b7b95d5..6545150 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -319,27 +319,6 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 		return 1;
 	}
 
-	if (logical_block_size_sectors <= 1)
-		return 0;
-
-	if (start & (logical_block_size_sectors - 1)) {
-		DMWARN("%s: start=%llu not aligned to h/w "
-		       "logical block size %u of %s",
-		       dm_device_name(ti->table->md),
-		       (unsigned long long)start,
-		       limits->logical_block_size, bdevname(bdev, b));
-		return 1;
-	}
-
-	if (len & (logical_block_size_sectors - 1)) {
-		DMWARN("%s: len=%llu not aligned to h/w "
-		       "logical block size %u of %s",
-		       dm_device_name(ti->table->md),
-		       (unsigned long long)len,
-		       limits->logical_block_size, bdevname(bdev, b));
-		return 1;
-	}
-
 	/*
 	 * If the target is mapped to zoned block device(s), check
 	 * that the zones are not partially mapped.
@@ -355,6 +334,15 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 			return 1;
 		}
 
+		/*
+		 * Note: The last zone of a zoned block device may be smaller
+		 * than other zones. So for a target mapping the end of a
+		 * zoned block device with such a zone, len would not be zone
+		 * aligned. We do not allow such last smaller zone to be part
+		 * of the mapping here to ensure that mappings with multiple
+		 * devices do not end up with a smaller zone in the middle of
+		 * the sector range.
+		 */
 		if (len & (zone_sectors - 1)) {
 			DMWARN("%s: len=%llu not aligned to h/w zone size %u of %s",
 			       dm_device_name(ti->table->md),
@@ -364,6 +352,27 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 		}
 	}
 
+	if (logical_block_size_sectors <= 1)
+		return 0;
+
+	if (start & (logical_block_size_sectors - 1)) {
+		DMWARN("%s: start=%llu not aligned to h/w "
+		       "logical block size %u of %s",
+		       dm_device_name(ti->table->md),
+		       (unsigned long long)start,
+		       limits->logical_block_size, bdevname(bdev, b));
+		return 1;
+	}
+
+	if (len & (logical_block_size_sectors - 1)) {
+		DMWARN("%s: len=%llu not aligned to h/w "
+		       "logical block size %u of %s",
+		       dm_device_name(ti->table->md),
+		       (unsigned long long)len,
+		       limits->logical_block_size, bdevname(bdev, b));
+		return 1;
+	}
+
 	return 0;
 }
 
-- 
2.9.4

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