From 4419d1ac7def3c2f74cab15e4a1c69cffcaadedd Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Sat, 10 Feb 2007 01:45:47 -0800 Subject: [PATCH] relax check for AIX in msdos partition table The patch to identify AIX disks and ignore them has caused at least one machine to fail to find the root partition on 2.6.19. The patch is: http://lkml.org/lkml/2006/7/31/117 The problem is some disk formatters do not blow away the first 4 bytes of the disk. If the disk we are installing to used to have AIX on it, then the first 4 bytes will still have IBMA in EBCDIC. The install in question was debian etch. Im not sure what the best fix is, perhaps the AIX detection code could check more than the first 4 bytes. The whole partition info for primary partitions is in this block: dd if=/dev/sdb count=$(( 4 * 16 )) bs=1 skip=$(( 0x1be )) All other data do not matter, beside the 0x55aa marker at the end of the first block. Signed-off-by: Olaf Hering Cc: OGAWA Hirofumi Cc: Anton Blanchard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/partitions/msdos.c | 12 +++++++++++- include/linux/genhd.h | 2 ++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c index 8c7af177781..dafd3b6b2dc 100644 --- a/fs/partitions/msdos.c +++ b/fs/partitions/msdos.c @@ -63,15 +63,25 @@ msdos_magic_present(unsigned char *p) #define AIX_LABEL_MAGIC4 0xC1 static int aix_magic_present(unsigned char *p, struct block_device *bdev) { + struct partition *pt = (struct partition *) (p + 0x1be); Sector sect; unsigned char *d; - int ret = 0; + int slot, 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; + /* Assume the partition table is valid if Linux partitions exists */ + for (slot = 1; slot <= 4; slot++, pt++) { + if (pt->sys_ind == LINUX_SWAP_PARTITION || + pt->sys_ind == LINUX_RAID_PARTITION || + pt->sys_ind == LINUX_DATA_PARTITION || + pt->sys_ind == LINUX_LVM_PARTITION || + is_extended_partition(pt)) + return 0; + } d = read_dev_sector(bdev, 7, §); if (d) { if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 0a022b2f63f..7a566fad3f7 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -21,6 +21,8 @@ enum { WIN98_EXTENDED_PARTITION = 0x0f, LINUX_SWAP_PARTITION = 0x82, + LINUX_DATA_PARTITION = 0x83, + LINUX_LVM_PARTITION = 0x8e, LINUX_RAID_PARTITION = 0xfd, /* autodetect RAID partition */ SOLARIS_X86_PARTITION = LINUX_SWAP_PARTITION, -- cgit v1.2.3