[PATCH 1/2] fs/partitions/msdos: add support for large disks

From: OGAWA Hirofumi
Date: Wed Mar 10 2010 - 10:48:37 EST

Hi,

This is rediff with fix of "Daniel Taylor" <Daniel.Taylor@xxxxxxx>.
Daniel, please check I'm breaking your patch.



From: "Daniel Taylor" <Daniel.Taylor@xxxxxxx>

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".

Signed-off-by: Daniel Taylor <daniel.taylor@xxxxxxx>
[tweaks and fix]
Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
---

fs/partitions/msdos.c | 74 +++++++++++++++++++++++++------------------------
1 file changed, 39 insertions(+), 35 deletions(-)

diff -puN fs/partitions/msdos.c~part-support-4k-block fs/partitions/msdos.c
--- linux-2.6/fs/partitions/msdos.c~part-support-4k-block 2010-03-07 04:10:48.000000000 +0900
+++ linux-2.6-hirofumi/fs/partitions/msdos.c 2010-03-07 19:41:56.000000000 +0900
@@ -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 START_SECT(p) ({ __le32 __a = get_unaligned(&p->start_sect); \
- le32_to_cpu(__a); \
- })
+#define SYS_IND(p) get_unaligned(&p->sys_ind)
+
+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 ch

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
* 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
*/
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_partitio
*/
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 *stat
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 *stat

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 *

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 *s

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 *
*/
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

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
*/
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 *st
/* 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 *st
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_partit

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_partit
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_partit

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;
_

--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
--
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