fs/partitions/msdos: add support for large disks

In order to use disks larger than 2TiB on Windows XP, it is necessary to
use 4096-byte logical sectors in an MBR.

Although the kernel storage and functions called from msdos.c used
"sector_t" internally, msdos.c still used u32 variables, which results in
the ability to handle XP-compatible large disks.

This patch changes the internal variables to "sector_t".

Daniel said: "In the near future, WD will be releasing products that need
this patch".

[hirofumi@mail.parknet.co.jp: tweaks and fix]
Signed-off-by: Daniel Taylor <daniel.taylor@wdc.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/partitions/msdos.c

@@ -31,14 +31,17 @@
  */
 #include <asm/unaligned.h>
 
-#define SYS_IND(p)	(get_unaligned(&p->sys_ind))
-#define NR_SECTS(p)	({ __le32 __a =	get_unaligned(&p->nr_sects);	\
-				le32_to_cpu(__a); \
-			})
+#define SYS_IND(p)	get_unaligned(&p->sys_ind)
 
-#define START_SECT(p)	({ __le32 __a =	get_unaligned(&p->start_sect);	\
-				le32_to_cpu(__a); \
-			})
+static inline sector_t nr_sects(struct partition *p)
+{
+	return (sector_t)get_unaligned_le32(&p->nr_sects);
+}
+
+static inline sector_t start_sect(struct partition *p)
+{
+	return (sector_t)get_unaligned_le32(&p->start_sect);
+}
 
 static inline int is_extended_partition(struct partition *p)
 {
@@ -104,13 +107,13 @@ static int aix_magic_present(unsigned char *p, struct block_device *bdev)
 
 static void
 parse_extended(struct parsed_partitions *state, struct block_device *bdev,
-			u32 first_sector, u32 first_size)
+			sector_t first_sector, sector_t first_size)
 {
 	struct partition *p;
 	Sector sect;
 	unsigned char *data;
-	u32 this_sector, this_size;
-	int sector_size = bdev_logical_block_size(bdev) / 512;
+	sector_t this_sector, this_size;
+	sector_t sector_size = bdev_logical_block_size(bdev) / 512;
 	int loopct = 0;		/* number of links followed
 				   without finding a data partition */
 	int i;
@@ -145,14 +148,14 @@ parse_extended(struct parsed_partitions *state, struct block_device *bdev,
 		 * First process the data partition(s)
 		 */
 		for (i=0; i<4; i++, p++) {
-			u32 offs, size, next;
-			if (!NR_SECTS(p) || is_extended_partition(p))
+			sector_t offs, size, next;
+			if (!nr_sects(p) || is_extended_partition(p))
 				continue;
 
 			/* Check the 3rd and 4th entries -
 			   these sometimes contain random garbage */
-			offs = START_SECT(p)*sector_size;
-			size = NR_SECTS(p)*sector_size;
+			offs = start_sect(p)*sector_size;
+			size = nr_sects(p)*sector_size;
 			next = this_sector + offs;
 			if (i >= 2) {
 				if (offs + size > this_size)
@@ -179,13 +182,13 @@ parse_extended(struct parsed_partitions *state, struct block_device *bdev,
 		 */
 		p -= 4;
 		for (i=0; i<4; i++, p++)
-			if (NR_SECTS(p) && is_extended_partition(p))
+			if (nr_sects(p) && is_extended_partition(p))
 				break;
 		if (i == 4)
 			goto done;	 /* nothing left to do */
 
-		this_sector = first_sector + START_SECT(p) * sector_size;
-		this_size = NR_SECTS(p) * sector_size;
+		this_sector = first_sector + start_sect(p) * sector_size;
+		this_size = nr_sects(p) * sector_size;
 		put_dev_sector(sect);
 	}
 done:
@@ -197,7 +200,7 @@ done:
 
 static void
 parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
-			u32 offset, u32 size, int origin)
+			sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_SOLARIS_X86_PARTITION
 	Sector sect;
@@ -244,7 +247,7 @@ parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
  */
 static void
 parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin, char *flavour,
+		sector_t offset, sector_t size, int origin, char *flavour,
 		int max_partitions)
 {
 	Sector sect;
@@ -263,7 +266,7 @@ parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
 	if (le16_to_cpu(l->d_npartitions) < max_partitions)
 		max_partitions = le16_to_cpu(l->d_npartitions);
 	for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) {
-		u32 bsd_start, bsd_size;
+		sector_t bsd_start, bsd_size;
 
 		if (state->next == state->limit)
 			break;
@@ -290,7 +293,7 @@ parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
 
 static void
 parse_freebsd(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin)
+		sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_BSD_DISKLABEL
 	parse_bsd(state, bdev, offset, size, origin,
@@ -300,7 +303,7 @@ parse_freebsd(struct parsed_partitions *state, struct block_device *bdev,
 
 static void
 parse_netbsd(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin)
+		sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_BSD_DISKLABEL
 	parse_bsd(state, bdev, offset, size, origin,
@@ -310,7 +313,7 @@ parse_netbsd(struct parsed_partitions *state, struct block_device *bdev,
 
 static void
 parse_openbsd(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin)
+		sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_BSD_DISKLABEL
 	parse_bsd(state, bdev, offset, size, origin,
@@ -324,7 +327,7 @@ parse_openbsd(struct parsed_partitions *state, struct block_device *bdev,
  */
 static void
 parse_unixware(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin)
+		sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_UNIXWARE_DISKLABEL
 	Sector sect;
@@ -348,7 +351,8 @@ parse_unixware(struct parsed_partitions *state, struct block_device *bdev,
 
 		if (p->s_label != UNIXWARE_FS_UNUSED)
 			put_partition(state, state->next++,
-						START_SECT(p), NR_SECTS(p));
+				      le32_to_cpu(p->start_sect),
+				      le32_to_cpu(p->nr_sects));
 		p++;
 	}
 	put_dev_sector(sect);
@@ -363,7 +367,7 @@ parse_unixware(struct parsed_partitions *state, struct block_device *bdev,
  */
 static void
 parse_minix(struct parsed_partitions *state, struct block_device *bdev,
-		u32 offset, u32 size, int origin)
+		sector_t offset, sector_t size, int origin)
 {
 #ifdef CONFIG_MINIX_SUBPARTITION
 	Sector sect;
@@ -390,7 +394,7 @@ parse_minix(struct parsed_partitions *state, struct block_device *bdev,
 			/* add each partition in use */
 			if (SYS_IND(p) == MINIX_PARTITION)
 				put_partition(state, state->next++,
-					      START_SECT(p), NR_SECTS(p));
+					      start_sect(p), nr_sects(p));
 		}
 		printk(" >\n");
 	}
@@ -401,7 +405,7 @@ parse_minix(struct parsed_partitions *state, struct block_device *bdev,
 static struct {
 	unsigned char id;
 	void (*parse)(struct parsed_partitions *, struct block_device *,
-			u32, u32, int);
+			sector_t, sector_t, int);
 } subtypes[] = {
 	{FREEBSD_PARTITION, parse_freebsd},
 	{NETBSD_PARTITION, parse_netbsd},
@@ -415,7 +419,7 @@ static struct {
  
 int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
 {
-	int sector_size = bdev_logical_block_size(bdev) / 512;
+	sector_t sector_size = bdev_logical_block_size(bdev) / 512;
 	Sector sect;
 	unsigned char *data;
 	struct partition *p;
@@ -483,8 +487,8 @@ int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
 
 	state->next = 5;
 	for (slot = 1 ; slot <= 4 ; slot++, p++) {
-		u32 start = START_SECT(p)*sector_size;
-		u32 size = NR_SECTS(p)*sector_size;
+		sector_t start = start_sect(p)*sector_size;
+		sector_t size = nr_sects(p)*sector_size;
 		if (!size)
 			continue;
 		if (is_extended_partition(p)) {
@@ -513,7 +517,7 @@ int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
 		unsigned char id = SYS_IND(p);
 		int n;
 
-		if (!NR_SECTS(p))
+		if (!nr_sects(p))
 			continue;
 
 		for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
@@ -521,8 +525,8 @@ int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
 
 		if (!subtypes[n].parse)
 			continue;
-		subtypes[n].parse(state, bdev, START_SECT(p)*sector_size,
-						NR_SECTS(p)*sector_size, slot);
+		subtypes[n].parse(state, bdev, start_sect(p)*sector_size,
+						nr_sects(p)*sector_size, slot);
 	}
 	put_dev_sector(sect);
 	return 1;