linux/fs/partitions/msdos.c
Olaf Hering e1dfa92dca [PATCH] ignore partition table on disks with AIX label
The on-disk data structures from AIX are not known, also the filesystem
layout is not known.  There is a msdos partition signature at the end of
the first block, and the kernel recognizes 3 small (and overlapping)
partitions.  But they are not usable.  Maybe the firmware uses it to find
the bootloader for AIX, but AIX boots also if the first block is cleared.

This is the content of the partition table:
 # dd if=/dev/sdb count=$(( 4 * 16 )) bs=1 skip=$(( 0x1be )) | xxd
0000000: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000010: 80ff ffff 41ff ffff 1b11 0000 381b 0000  ....A.......8...
0000020: 00ff ffff 41ff ffff 0211 0000 1900 0000  ....A...........
0000030: 80ff ffff 41ff ffff 1b11 0000 381b 0000  ....A.......8...

Handle the whole disk as empty disk.

This fixes also YaST which compares the output from parted (and formerly
fdisk) with /proc/partitions.  fdisk recognizes the AIX label since a long
time, SuSE has a patch for parted to handle the disk label as unknown.

dmesg will look like this:
 sda: [AIX]  unknown partition table

Tested on an IBM B50 with AIX V4.3.3.

Signed-off-by: Olaf Hering <olh@suse.de>
Cc: Albert Cahalan <acahalan@gmail.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:09 -07:00

505 lines
13 KiB
C

/*
* 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 "check.h"
#include "msdos.h"
#include "efi.h"
/*
* Many architectures don't like unaligned accesses, while
* the nr_sects and start_sect partition table entries are
* at a 2 (mod 4) address.
*/
#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);
}
#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);
}
/* Value is EBCDIC 'IBMA' */
#define AIX_LABEL_MAGIC1 0xC9
#define AIX_LABEL_MAGIC2 0xC2
#define AIX_LABEL_MAGIC3 0xD4
#define AIX_LABEL_MAGIC4 0xC1
static int aix_magic_present(unsigned char *p, struct block_device *bdev)
{
Sector sect;
unsigned char *d;
int ret = 0;
if (p[0] != AIX_LABEL_MAGIC1 &&
p[1] != AIX_LABEL_MAGIC2 &&
p[2] != AIX_LABEL_MAGIC3 &&
p[3] != AIX_LABEL_MAGIC4)
return 0;
d = read_dev_sector(bdev, 7, &sect);
if (d) {
if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M')
ret = 1;
put_dev_sector(sect);
};
return ret;
}
/*
* 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
parse_extended(struct parsed_partitions *state, struct block_device *bdev,
u32 first_sector, u32 first_size)
{
struct partition *p;
Sector sect;
unsigned char *data;
u32 this_sector, this_size;
int sector_size = bdev_hardsect_size(bdev) / 512;
int loopct = 0; /* number of links followed
without finding a data partition */
int i;
this_sector = first_sector;
this_size = first_size;
while (1) {
if (++loopct > 100)
return;
if (state->next == state->limit)
return;
data = read_dev_sector(bdev, this_sector, &sect);
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++) {
u32 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;
}
put_partition(state, state->next, next, size);
if (SYS_IND(p) == LINUX_RAID_PARTITION)
state->parts[state->next].flags = 1;
loopct = 0;
if (++state->next == state->limit)
goto done;
}
/*
* Next, process the (first) extended partition, if present.
* (So far, there seems to be no reason to make
* parse_extended() recursive and allow a tree
* of extended partitions.)
* It should be a link to the next logical 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;
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
parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_SOLARIS_X86_PARTITION
Sector sect;
struct solaris_x86_vtoc *v;
int i;
v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, &sect);
if (!v)
return;
if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) {
put_dev_sector(sect);
return;
}
printk(" %s%d: <solaris:", state->name, origin);
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 && state->next<state->limit; i++) {
struct solaris_x86_slice *s = &v->v_slice[i];
if (s->s_size == 0)
continue;
printk(" [s%d]", i);
/* solaris partitions are relative to current MS-DOS
* one; must add the offset of the current partition */
put_partition(state, state->next++,
le32_to_cpu(s->s_start)+offset,
le32_to_cpu(s->s_size));
}
put_dev_sector(sect);
printk(" >\n");
#endif
}
#if defined(CONFIG_BSD_DISKLABEL)
/*
* Create devices for BSD partitions listed in a disklabel, under a
* dos-like partition. See parse_extended() for more information.
*/
static void
parse_bsd(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin, char *flavour,
int max_partitions)
{
Sector sect;
struct bsd_disklabel *l;
struct bsd_partition *p;
l = (struct bsd_disklabel *)read_dev_sector(bdev, offset+1, &sect);
if (!l)
return;
if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) {
put_dev_sector(sect);
return;
}
printk(" %s%d: <%s:", state->name, origin, flavour);
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;
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);
if (offset == bsd_start && size == bsd_size)
/* full parent partition, we have it already */
continue;
if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
printk("bad subpartition - ignored\n");
continue;
}
put_partition(state, state->next++, bsd_start, bsd_size);
}
put_dev_sector(sect);
if (le16_to_cpu(l->d_npartitions) > max_partitions)
printk(" (ignored %d more)",
le16_to_cpu(l->d_npartitions) - max_partitions);
printk(" >\n");
}
#endif
static void
parse_freebsd(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, bdev, offset, size, origin,
"bsd", BSD_MAXPARTITIONS);
#endif
}
static void
parse_netbsd(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, bdev, offset, size, origin,
"netbsd", BSD_MAXPARTITIONS);
#endif
}
static void
parse_openbsd(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_BSD_DISKLABEL
parse_bsd(state, bdev, offset, size, origin,
"openbsd", OPENBSD_MAXPARTITIONS);
#endif
}
/*
* Create devices for Unixware partitions listed in a disklabel, under a
* dos-like partition. See parse_extended() for more information.
*/
static void
parse_unixware(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_UNIXWARE_DISKLABEL
Sector sect;
struct unixware_disklabel *l;
struct unixware_slice *p;
l = (struct unixware_disklabel *)read_dev_sector(bdev, offset+29, &sect);
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%d: <unixware:", state->name, origin);
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 (state->next == state->limit)
break;
if (p->s_label != UNIXWARE_FS_UNUSED)
put_partition(state, state->next++,
START_SECT(p), NR_SECTS(p));
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
parse_minix(struct parsed_partitions *state, struct block_device *bdev,
u32 offset, u32 size, int origin)
{
#ifdef CONFIG_MINIX_SUBPARTITION
Sector sect;
unsigned char *data;
struct partition *p;
int i;
data = read_dev_sector(bdev, offset, &sect);
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%d: <minix:", state->name, origin);
for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
if (state->next == state->limit)
break;
/* add each partition in use */
if (SYS_IND(p) == MINIX_PARTITION)
put_partition(state, state->next++,
START_SECT(p), NR_SECTS(p));
}
printk(" >\n");
}
put_dev_sector(sect);
#endif /* CONFIG_MINIX_SUBPARTITION */
}
static struct {
unsigned char id;
void (*parse)(struct parsed_partitions *, struct block_device *,
u32, u32, int);
} subtypes[] = {
{FREEBSD_PARTITION, parse_freebsd},
{NETBSD_PARTITION, parse_netbsd},
{OPENBSD_PARTITION, parse_openbsd},
{MINIX_PARTITION, parse_minix},
{UNIXWARE_PARTITION, parse_unixware},
{SOLARIS_X86_PARTITION, parse_solaris_x86},
{NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
{0, NULL},
};
int msdos_partition(struct parsed_partitions *state, struct block_device *bdev)
{
int sector_size = bdev_hardsect_size(bdev) / 512;
Sector sect;
unsigned char *data;
struct partition *p;
int slot;
data = read_dev_sector(bdev, 0, &sect);
if (!data)
return -1;
if (!msdos_magic_present(data + 510)) {
put_dev_sector(sect);
return 0;
}
if (aix_magic_present(data, bdev)) {
put_dev_sector(sect);
printk( " [AIX]");
return 0;
}
/*
* Now that the 55aa signature is present, this is probably
* either the boot sector of a FAT filesystem or a DOS-type
* partition table. Reject this in case the boot indicator
* is not 0 or 0x80.
*/
p = (struct partition *) (data + 0x1be);
for (slot = 1; slot <= 4; slot++, p++) {
if (p->boot_ind != 0 && p->boot_ind != 0x80) {
put_dev_sector(sect);
return 0;
}
}
#ifdef CONFIG_EFI_PARTITION
p = (struct partition *) (data + 0x1be);
for (slot = 1 ; slot <= 4 ; slot++, p++) {
/* If this is an EFI GPT disk, msdos should ignore it. */
if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
put_dev_sector(sect);
return 0;
}
}
#endif
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.
*/
state->next = 5;
for (slot = 1 ; slot <= 4 ; slot++, p++) {
u32 start = START_SECT(p)*sector_size;
u32 size = NR_SECTS(p)*sector_size;
if (!size)
continue;
if (is_extended_partition(p)) {
/* prevent someone doing mkfs or mkswap on an
extended partition, but leave room for LILO */
put_partition(state, slot, start, size == 1 ? 1 : 2);
printk(" <");
parse_extended(state, bdev, start, size);
printk(" >");
continue;
}
put_partition(state, slot, start, size);
if (SYS_IND(p) == LINUX_RAID_PARTITION)
state->parts[slot].flags = 1;
if (SYS_IND(p) == DM6_PARTITION)
printk("[DM]");
if (SYS_IND(p) == EZD_PARTITION)
printk("[EZD]");
}
printk("\n");
/* second pass - output for each on a separate line */
p = (struct partition *) (0x1be + data);
for (slot = 1 ; slot <= 4 ; slot++, 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)
continue;
subtypes[n].parse(state, bdev, START_SECT(p)*sector_size,
NR_SECTS(p)*sector_size, slot);
}
put_dev_sector(sect);
return 1;
}