[PATCH 2/2] fs/partition/msdos: Fix unusable extended partition for > 512B sector

[OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>]

We can drop this patch, if we want to delay until someone notice this
and have some real requests to this.




Smaller size than a minimum blocksize can't be used, after all it's
handled like 0 size.

For extended partition itself, this makes sure to use bigger size than
one logical sector size at least.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
---

 fs/partitions/msdos.c |   13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff -puN fs/partitions/msdos.c~part-support-4k-block-fix fs/partitions/msdos.c
--- linux-2.6/fs/partitions/msdos.c~part-support-4k-block-fix	2010-03-08 20:11:39.000000000 +0900
+++ linux-2.6-hirofumi/fs/partitions/msdos.c	2010-03-08 20:32:19.000000000 +0900
@@ -492,9 +492,16 @@ int msdos_partition(struct parsed_partit
 		if (!size)
 			continue;
 		if (is_extended_partition(p)) {
-			/* prevent someone doing mkfs or mkswap on an
-			   extended partition, but leave room for LILO */
-			put_partition(state, slot, start, size == 1 ? 1 : 2);
+			/*
+			 * prevent someone doing mkfs or mkswap on an
+			 * extended partition, but leave room for LILO
+			 * FIXME: this uses one logical sector for > 512b
+			 * sector, although it may not be enough/proper.
+			 */
+			sector_t n = 2;
+			n = min(size, max(sector_size, n));
+			put_partition(state, slot, start, n);
+
 			printk(" <");
 			parse_extended(state, bdev, start, size);
 			printk(" >");
_

--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>