mkfs.f2fs: Fix zoned alignment check for multi-device setups

Commit 84447ee correctly relocated the zone alignment check to its
proper location. However, this revealed that the original check's
condition was incorrect for multi-device setups.

This patch corrects the logic to check the alignment relative to the start
of the segment0 and improves the error messages.

Signed-off-by: Daniel Lee <chullee@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Daniel Lee

mkfs/f2fs_format.c

@@ -339,17 +339,6 @@ static int f2fs_prepare_super_block(void)
 	MSG(0, "Info: zone aligned segment0 blkaddr: %u\n",
 					get_sb(segment0_blkaddr));
 
-	if (c.zoned_mode &&
-		((c.ndevs == 1 &&
-			(get_sb(segment0_blkaddr) + c.start_sector /
-			DEFAULT_SECTORS_PER_BLOCK) % c.zone_blocks) ||
-		(c.ndevs > 1 &&
-			c.devices[1].start_blkaddr % c.zone_blocks))) {
-		MSG(1, "\tError: Unaligned segment0 block address %u\n",
-				get_sb(segment0_blkaddr));
-		return -1;
-	}
-
 	for (i = 0; i < c.ndevs; i++) {
 		if (i == 0) {
 			c.devices[i].total_segments =
@@ -390,6 +379,33 @@ static int f2fs_prepare_super_block(void)
 
 		c.total_segments += c.devices[i].total_segments;
 	}
+
+	if (c.zoned_mode) {
+		if (c.ndevs == 1 &&
+			(get_sb(segment0_blkaddr) + c.start_sector /
+			DEFAULT_SECTORS_PER_BLOCK) % c.zone_blocks) {
+			/*
+			 * With a sole zoned LU, segment0 start should be
+			 * aligned at the zone.
+			 */
+			MSG(1, "\tError: Unaligned segment0 start (%u) for zoned LU (zone_blocks: %lu)\n",
+				get_sb(segment0_blkaddr), c.zone_blocks);
+			return -1;
+		} else if (c.ndevs > 1 &&
+			(c.devices[1].start_blkaddr - get_sb(segment0_blkaddr)) % c.zone_blocks) {
+			/*
+			 * With the first device as a conventional LU and the
+			 * second as a zoned LU, the start address for the zoned
+			 * LU should be aligned to the zone size, starting from
+			 * segment0.
+			 */
+			MSG(1, "\tError: Unaligned start (%lu) for zoned LU from segment0 (%u) (zone_blocks: %lu)\n",
+				c.devices[1].start_blkaddr,
+				get_sb(segment0_blkaddr), c.zone_blocks);
+			return -1;
+		}
+	}
+
 	set_sb(segment_count, c.total_segments);
 	set_sb(segment_count_ckpt, F2FS_NUMBER_OF_CHECKPOINT_PACK);