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/*
* fs/partitions/msdos.c
*
* Code extracted from drivers/block/genhd.c
* Copyright (C) 1991-1998 Linus Torvalds
*
* Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
* in the early extended-partition checks and added DM partitions
*
* Support for DiskManager v6.0x added by Mark Lord,
* with information provided by OnTrack. This now works for linux fdisk
* and LILO, as well as loadlin and bootln. Note that disks other than
* /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
*
* More flexible handling of extended partitions - aeb, 950831
*
* Check partition table on IDE disks for common CHS translations
*
* Re-organised Feb 1998 Russell King
*/
#include <linux/config.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/blk.h>
#ifdef CONFIG_BLK_DEV_IDE
#include <linux/ide.h> /* IDE xlate */
#endif /* CONFIG_BLK_DEV_IDE */
#include <asm/system.h>
#include "check.h"
#include "msdos.h"
#if CONFIG_BLK_DEV_MD
extern void md_autodetect_dev(kdev_t dev);
#endif
/*
* Many architectures don't like unaligned accesses, which is
* frequently the case with the nr_sects and start_sect partition
* table entries.
*/
#include <asm/unaligned.h>
#define SYS_IND(p) (get_unaligned(&p->sys_ind))
#define NR_SECTS(p) ({ __typeof__(p->nr_sects) __a = \
get_unaligned(&p->nr_sects); \
le32_to_cpu(__a); \
})
#define START_SECT(p) ({ __typeof__(p->start_sect) __a = \
get_unaligned(&p->start_sect); \
le32_to_cpu(__a); \
})
static inline int is_extended_partition(struct partition *p)
{
return (SYS_IND(p) == DOS_EXTENDED_PARTITION ||
SYS_IND(p) == WIN98_EXTENDED_PARTITION ||
SYS_IND(p) == LINUX_EXTENDED_PARTITION);
}
/*
* partition_name() formats the short partition name into the supplied
* buffer, and returns a pointer to that buffer.
* Used by several partition types which makes conditional inclusion messy,
* use __attribute__ ((unused)) instead.
*/
static char __attribute__ ((unused))
*partition_name (struct gendisk *hd, int minor, char *buf)
{
#ifdef CONFIG_DEVFS_FS
sprintf(buf, "p%d", (minor & ((1 << hd->minor_shift) - 1)));
return buf;
#else
return disk_name(hd, minor, buf);
#endif
}
#define MSDOS_LABEL_MAGIC1 0x55
#define MSDOS_LABEL_MAGIC2 0xAA
static inline int
msdos_magic_present(unsigned char *p)
{
return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2);
}
/*
* Create devices for each logical partition in an extended partition.
* The logical partitions form a linked list, with each entry being
* a partition table with two entries. The first entry
* is the real data partition (with a start relative to the partition
* table start). The second is a pointer to the next logical partition
* (with a start relative to the entire extended partition).
* We do not create a Linux partition for the partition tables, but
* only for the actual data partitions.
*/
static void extended_partition(struct gendisk *hd, struct block_device *bdev,
int minor, unsigned long first_size, int *current_minor)
{
struct partition *p;
Sector sect;
unsigned char *data;
unsigned long first_sector, this_sector, this_size;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
int i;
this_sector = first_sector = hd->part[minor].start_sect;
this_size = first_size;
while (1) {
if (++loopct > 100)
return;
if ((*current_minor & mask) == 0)
return;
data = read_dev_sector(bdev, this_sector, §);
if (!data)
return;
if (!msdos_magic_present(data + 510))
goto done;
p = (struct partition *) (data + 0x1be);
/*
* Usually, the first entry is the real data partition,
* the 2nd entry is the next extended partition, or empty,
* and the 3rd and 4th entries are unused.
* However, DRDOS sometimes has the extended partition as
* the first entry (when the data partition is empty),
* and OS/2 seems to use all four entries.
*/
/*
* First process the data partition(s)
*/
for (i=0; i<4; i++, p++) {
unsigned long 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;
next = this_sector + offs;
if (i >= 2) {
if (offs + size > this_size)
continue;
if (next < first_sector)
continue;
if (next + size > first_sector + first_size)
continue;
}
add_gd_partition(hd, *current_minor, next, size);
#if CONFIG_BLK_DEV_MD
if (SYS_IND(p) == LINUX_RAID_PARTITION) {
md_autodetect_dev(MKDEV(hd->major,*current_minor));
}
#endif
(*current_minor)++;
loopct = 0;
if ((*current_minor & mask) == 0)
goto done;
}
/*
* Next, process the (first) extended partition, if present.
* (So far, there seems to be no reason to make
* extended_partition() recursive and allow a tree
* of extended partitions.)
* It should be a link to the next logical partition.
* Create a minor for this just long enough to get the next
* partition table. The minor will be reused for the next
* data partition.
*/
p -= 4;
for (i=0; i<4; i++, 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;
minor = *current_minor;
put_dev_sector(sect);
}
done:
put_dev_sector(sect);
}
/* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also
indicates linux swap. Be careful before believing this is Solaris. */
static void
solaris_x86_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_SOLARIS_X86_PARTITION
long offset = hd->part[minor].start_sect;
Sector sect;
struct solaris_x86_vtoc *v;
struct solaris_x86_slice *s;
int mask = (1 << hd->minor_shift) - 1;
int i;
char buf[40];
v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, §);
if (!v)
return;
if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
put_dev_sector(sect);
return;
}
printk(" %s: <solaris:", partition_name(hd, minor, buf));
if (le32_to_cpu(v->v_version) != 1) {
printk(" cannot handle version %d vtoc>\n",
le32_to_cpu(v->v_version));
put_dev_sector(sect);
return;
}
for (i=0; i<SOLARIS_X86_NUMSLICE; i++) {
if ((*current_minor & mask) == 0)
break;
s = &v->v_slice[i];
if (s->s_size == 0)
continue;
printk(" [s%d]", i);
/* solaris partitions are relative to current MS-DOS
* one but add_gd_partition starts relative to sector
* zero of the disk. Therefore, must add the offset
* of the current partition */
add_gd_partition(hd, *current_minor,
le32_to_cpu(s->s_start)+offset,
le32_to_cpu(s->s_size));
(*current_minor)++;
}
put_dev_sector(sect);
printk(" >\n");
#endif
}
#ifdef CONFIG_BSD_DISKLABEL
static void
check_and_add_bsd_partition(struct gendisk *hd, struct bsd_partition *bsd_p,
int baseminor, int *current_minor)
{
int i, bsd_start, bsd_size;
bsd_start = le32_to_cpu(bsd_p->p_offset);
bsd_size = le32_to_cpu(bsd_p->p_size);
/* check relative position of already allocated partitions */
for (i = baseminor+1; i < *current_minor; i++) {
int start = hd->part[i].start_sect;
int size = hd->part[i].nr_sects;
if (start+size <= bsd_start || start >= bsd_start+bsd_size)
continue; /* no overlap */
if (start == bsd_start && size == bsd_size)
return; /* equal -> no need to add */
if (start <= bsd_start && start+size >= bsd_start+bsd_size) {
/* bsd living within dos partition */
#ifdef DEBUG_BSD_DISKLABEL
printk("w: %d %ld+%ld,%d+%d",
i, start, size, bsd_start, bsd_size);
#endif
break; /* ok */
}
/* ouch: bsd and linux overlap */
#ifdef DEBUG_BSD_DISKLABEL
printk("???: %d %ld+%ld,%d+%d",
i, start, size, bsd_start, bsd_size);
#endif
printk("???");
return;
}
add_gd_partition(hd, *current_minor, bsd_start, bsd_size);
(*current_minor)++;
}
/*
* Create devices for BSD partitions listed in a disklabel, under a
* dos-like partition. See extended_partition() for more information.
*/
static void do_bsd_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor, char *name, int max_partitions)
{
long offset = hd->part[minor].start_sect;
Sector sect;
struct bsd_disklabel *l;
struct bsd_partition *p;
int mask = (1 << hd->minor_shift) - 1;
int baseminor = (minor & ~mask);
char buf[40];
l = (struct bsd_disklabel *)read_dev_sector(bdev, offset+1, §);
if (!l)
return;
if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
put_dev_sector(sect);
return;
}
printk(" %s: <%s:", partition_name(hd, minor, buf), name);
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++) {
if ((*current_minor & mask) == 0)
break;
if (p->p_fstype == BSD_FS_UNUSED)
continue;
check_and_add_bsd_partition(hd, p, baseminor, current_minor);
}
put_dev_sector(sect);
printk(" >\n");
}
#endif
static void bsd_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_BSD_DISKLABEL
do_bsd_partition(hd, bdev, minor, current_minor, "bsd",
BSD_MAXPARTITIONS);
#endif
}
static void netbsd_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_BSD_DISKLABEL
do_bsd_partition(hd, bdev, minor, current_minor, "netbsd",
BSD_MAXPARTITIONS);
#endif
}
static void openbsd_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_BSD_DISKLABEL
do_bsd_partition(hd, bdev, minor, current_minor,
"openbsd", OPENBSD_MAXPARTITIONS);
#endif
}
/*
* Create devices for Unixware partitions listed in a disklabel, under a
* dos-like partition. See extended_partition() for more information.
*/
static void unixware_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_UNIXWARE_DISKLABEL
long offset = hd->part[minor].start_sect;
Sector sect;
struct unixware_disklabel *l;
struct unixware_slice *p;
int mask = (1 << hd->minor_shift) - 1;
char buf[40];
l = (struct unixware_disklabel *)read_dev_sector(bdev, offset+29, §);
if (!l)
return;
if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
put_dev_sector(sect);
return;
}
printk(" %s: <unixware:", partition_name(hd, minor, buf));
p = &l->vtoc.v_slice[1];
/* I omit the 0th slice as it is the same as whole disk. */
while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
if ((*current_minor & mask) == 0)
break;
if (p->s_label != UNIXWARE_FS_UNUSED) {
add_gd_partition(hd, *current_minor, START_SECT(p),
NR_SECTS(p));
(*current_minor)++;
}
p++;
}
put_dev_sector(sect);
printk(" >\n");
#endif
}
/*
* Minix 2.0.0/2.0.2 subpartition support.
* Anand Krishnamurthy <anandk@wiproge.med.ge.com>
* Rajeev V. Pillai <rajeevvp@yahoo.com>
*/
static void minix_partition(struct gendisk *hd, struct block_device *bdev,
int minor, int *current_minor)
{
#ifdef CONFIG_MINIX_SUBPARTITION
long offset = hd->part[minor].start_sect;
Sector sect;
unsigned char *data;
struct partition *p;
int mask = (1 << hd->minor_shift) - 1;
int i;
char buf[40];
data = read_dev_sector(bdev, offset, §);
if (!data)
return;
p = (struct partition *)(data + 0x1be);
/* The first sector of a Minix partition can have either
* a secondary MBR describing its subpartitions, or
* the normal boot sector. */
if (msdos_magic_present (data + 510) &&
SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
printk(" %s: <minix:", partition_name(hd, minor, buf));
for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
if ((*current_minor & mask) == 0)
break;
/* add each partition in use */
if (SYS_IND(p) == MINIX_PARTITION) {
add_gd_partition(hd, *current_minor,
START_SECT(p), NR_SECTS(p));
(*current_minor)++;
}
}
printk(" >\n");
}
put_dev_sector(sect);
#endif /* CONFIG_MINIX_SUBPARTITION */
}
static struct {
unsigned char id;
void (*parse)(struct gendisk *, struct block_device *, int, int *);
} subtypes[] = {
{BSD_PARTITION, bsd_partition},
{NETBSD_PARTITION, netbsd_partition},
{OPENBSD_PARTITION, openbsd_partition},
{MINIX_PARTITION, minix_partition},
{UNIXWARE_PARTITION, unixware_partition},
{SOLARIS_X86_PARTITION, solaris_x86_partition},
{0, NULL},
};
/*
* Look for various forms of IDE disk geometry translation
*/
static int handle_ide_mess(struct block_device *bdev)
{
#ifdef CONFIG_BLK_DEV_IDE
Sector sect;
unsigned char *data;
kdev_t dev = to_kdev_t(bdev->bd_dev);
unsigned int sig;
int heads = 0;
struct partition *p;
int i;
/*
* The i386 partition handling programs very often
* make partitions end on cylinder boundaries.
* There is no need to do so, and Linux fdisk doesnt always
* do this, and Windows NT on Alpha doesnt do this either,
* but still, this helps to guess #heads.
*/
data = read_dev_sector(bdev, 0, §);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
sig = le16_to_cpu(*(unsigned short *)(data + 2));
p = (struct partition *) (data + 0x1be);
for (i = 0; i < 4; i++) {
struct partition *q = &p[i];
if (NR_SECTS(q)) {
if ((q->sector & 63) == 1 &&
(q->end_sector & 63) == 63)
heads = q->end_head + 1;
break;
}
}
if (SYS_IND(p) == EZD_PARTITION) {
/*
* Accesses to sector 0 must go to sector 1 instead.
*/
if (ide_xlate_1024(dev, -1, heads, " [EZD]"))
goto reread;
} else if (SYS_IND(p) == DM6_PARTITION) {
/*
* Everything on the disk is offset by 63 sectors,
* including a "new" MBR with its own partition table.
*/
if (ide_xlate_1024(dev, 1, heads, " [DM6:DDO]"))
goto reread;
} else if (sig <= 0x1ae &&
data[sig] == 0xAA && data[sig+1] == 0x55 &&
(data[sig+2] & 1)) {
/* DM6 signature in MBR, courtesy of OnTrack */
(void) ide_xlate_1024 (dev, 0, heads, " [DM6:MBR]");
} else if (SYS_IND(p) == DM6_AUX1PARTITION ||
SYS_IND(p) == DM6_AUX3PARTITION) {
/*
* DM6 on other than the first (boot) drive
*/
(void) ide_xlate_1024(dev, 0, heads, " [DM6:AUX]");
} else {
(void) ide_xlate_1024(dev, 2, heads, " [PTBL]");
}
put_dev_sector(sect);
return 1;
reread:
put_dev_sector(sect);
/* Flush the cache */
invalidate_bdev(bdev, 1);
truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
#endif /* CONFIG_BLK_DEV_IDE */
return 1;
}
int msdos_partition(struct gendisk *hd, struct block_device *bdev,
unsigned long first_sector, int first_part_minor)
{
int i, minor = first_part_minor;
Sector sect;
struct partition *p;
unsigned char *data;
int mask = (1 << hd->minor_shift) - 1;
int sector_size = get_hardsect_size(to_kdev_t(bdev->bd_dev)) / 512;
int current_minor = first_part_minor;
int err;
err = handle_ide_mess(bdev);
if (err <= 0)
return err;
data = read_dev_sector(bdev, 0, §);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
p = (struct partition *) (data + 0x1be);
/*
* Look for partitions in two passes:
* First find the primary and DOS-type extended partitions.
* On the second pass look inside *BSD, Unixware and Solaris partitions.
*/
current_minor += 4;
for (i=1 ; i<=4 ; minor++,i++,p++) {
if (!NR_SECTS(p))
continue;
add_gd_partition(hd, minor,
first_sector+START_SECT(p)*sector_size,
NR_SECTS(p)*sector_size);
#if CONFIG_BLK_DEV_MD
if (SYS_IND(p) == LINUX_RAID_PARTITION) {
md_autodetect_dev(MKDEV(hd->major,minor));
}
#endif
if (is_extended_partition(p)) {
unsigned long size = hd->part[minor].nr_sects;
printk(" <");
/* prevent someone doing mkfs or mkswap on an
extended partition, but leave room for LILO */
if (size > 2)
hd->part[minor].nr_sects = 2;
extended_partition(hd, bdev, minor, size, ¤t_minor);
printk(" >");
}
}
/*
* Check for old-style Disk Manager partition table
*/
if (msdos_magic_present(data + 0xfc)) {
p = (struct partition *) (0x1be + data);
for (i = 4 ; i < 16 ; i++, current_minor++) {
p--;
if ((current_minor & mask) == 0)
break;
if (!(START_SECT(p) && NR_SECTS(p)))
continue;
add_gd_partition(hd, current_minor, START_SECT(p), NR_SECTS(p));
}
}
printk("\n");
/* second pass - output for each on a separate line */
minor -= 4;
p = (struct partition *) (0x1be + data);
for (i=1 ; i<=4 ; minor++,i++,p++) {
unsigned char id = SYS_IND(p);
int n;
if (!NR_SECTS(p))
continue;
for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
;
if (subtypes[n].parse)
subtypes[n].parse(hd, bdev, minor, ¤t_minor);
}
put_dev_sector(sect);
return 1;
}
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