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Subject[PATCH] msdos: add support for large disks
Date
From
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@wdc.com>
---
diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
index 0028d2e..fa9c77d 100644
--- a/fs/partitions/msdos.c
+++ b/fs/partitions/msdos.c
@@ -104,12 +104,12 @@ 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;
+ sector_t this_sector, this_size;
int sector_size = bdev_logical_block_size(bdev) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
@@ -145,15 +145,16 @@ 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;
+ 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 =
(sector_t)(START_SECT(p))*(sector_t)(sector_size);
+ size =
(sector_t)(NR_SECTS(p))*(sector_t)(sector_size);
next = this_sector + offs;
+
if (i >= 2) {
if (offs + size > this_size)
continue;
@@ -184,8 +185,8 @@ parse_extended(struct parsed_partitions *state, struct
block_device *bdev,
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 + (sector_t)(START_SECT(p)) *
sector_size;
+ this_size = (sector_t)(NR_SECTS(p)) *
(sector_t)(sector_size);
put_dev_sector(sect);
}
done:
@@ -197,7 +198,7 @@ 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 +245,7 @@ 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;
@@ -263,14 +264,14 @@ 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;
if (p->p_fstype == BSD_FS_UNUSED)
continue;
- bsd_start = le32_to_cpu(p->p_offset);
- bsd_size = le32_to_cpu(p->p_size);
+ bsd_start = (sector_t)(le32_to_cpu(p->p_offset));
+ bsd_size = (sector_t)(le32_to_cpu(p->p_size));
if (offset == bsd_start && size == bsd_size)
/* full parent partition, we have it already */
continue;
@@ -290,7 +291,7 @@ 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 +301,7 @@ 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 +311,7 @@ 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 +325,7 @@ 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;
@@ -363,7 +364,7 @@ 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;
@@ -401,7 +402,7 @@ 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},
@@ -483,8 +484,8 @@ 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 =
(sector_t)(START_SECT(p))*(sector_t)(sector_size);
+ sector_t size =
(sector_t)(NR_SECTS(p))*(sector_t)(sector_size);
if (!size)
continue;
if (is_extended_partition(p)) {
@@ -521,8 +522,8 @@ 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,
(sector_t)(START_SECT(p))*(sector_t)(sector_size),
+
(sector_t)(NR_SECTS(p))*(sector_t)(sector_size), slot);
}
put_dev_sector(sect);
return 1;


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