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>

1 files changed, 38 insertions, 34 deletions

diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
index 0028d2ef0662..b78385840a55 100644
--- a/fs/partitions/msdos.c
+++ b/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;