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linux/fs/partitions/osf.c
Linus Torvalds 34d211a2d5 Increase OSF partition limit from 8 to 18
It turns out that while a maximum of 8 partitions may be what people
"should" have had, you can actually fit up to 18 entries(*) in a sector.

And some people clearly were taking advantage of that, like Michael
Cree, who had ten partitions on one of his OSF disks.

(*) The OSF partition data starts at byte offset 64 in the first sector,
    and the array of 16-byte partition entries start at offset 148 in
    the on-disk partition structure.

Reported-by: Michael Cree <mcree@orcon.net.nz>
Cc: stable@kernel.org (v2.6.38)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-16 08:04:07 -07:00

87 lines
1.9 KiB
C

/*
* fs/partitions/osf.c
*
* Code extracted from drivers/block/genhd.c
*
* Copyright (C) 1991-1998 Linus Torvalds
* Re-organised Feb 1998 Russell King
*/
#include "check.h"
#include "osf.h"
#define MAX_OSF_PARTITIONS 18
int osf_partition(struct parsed_partitions *state)
{
int i;
int slot = 1;
unsigned int npartitions;
Sector sect;
unsigned char *data;
struct disklabel {
__le32 d_magic;
__le16 d_type,d_subtype;
u8 d_typename[16];
u8 d_packname[16];
__le32 d_secsize;
__le32 d_nsectors;
__le32 d_ntracks;
__le32 d_ncylinders;
__le32 d_secpercyl;
__le32 d_secprtunit;
__le16 d_sparespertrack;
__le16 d_sparespercyl;
__le32 d_acylinders;
__le16 d_rpm, d_interleave, d_trackskew, d_cylskew;
__le32 d_headswitch, d_trkseek, d_flags;
__le32 d_drivedata[5];
__le32 d_spare[5];
__le32 d_magic2;
__le16 d_checksum;
__le16 d_npartitions;
__le32 d_bbsize, d_sbsize;
struct d_partition {
__le32 p_size;
__le32 p_offset;
__le32 p_fsize;
u8 p_fstype;
u8 p_frag;
__le16 p_cpg;
} d_partitions[MAX_OSF_PARTITIONS];
} * label;
struct d_partition * partition;
data = read_part_sector(state, 0, &sect);
if (!data)
return -1;
label = (struct disklabel *) (data+64);
partition = label->d_partitions;
if (le32_to_cpu(label->d_magic) != DISKLABELMAGIC) {
put_dev_sector(sect);
return 0;
}
if (le32_to_cpu(label->d_magic2) != DISKLABELMAGIC) {
put_dev_sector(sect);
return 0;
}
npartitions = le16_to_cpu(label->d_npartitions);
if (npartitions > MAX_OSF_PARTITIONS) {
put_dev_sector(sect);
return 0;
}
for (i = 0 ; i < npartitions; i++, partition++) {
if (slot == state->limit)
break;
if (le32_to_cpu(partition->p_size))
put_partition(state, slot,
le32_to_cpu(partition->p_offset),
le32_to_cpu(partition->p_size));
slot++;
}
strlcat(state->pp_buf, "\n", PAGE_SIZE);
put_dev_sector(sect);
return 1;
}