From 1ad7e89940d5ac411928189e1a4a01901dbf590f Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Thu, 8 Nov 2012 16:12:25 -0800 Subject: block: store partition_meta_info.uuid as a string This will allow other types of UUID to be stored here, aside from true UUIDs. This also simplifies code that uses this field, since it's usually constructed from a, used as a, or compared to other, strings. Note: A simplistic approach here would be to set uuid_str[36]=0 whenever a /PARTNROFF option was found to be present. However, this modifies the input string, and causes subsequent calls to devt_from_partuuid() not to see the /PARTNROFF option, which causes different results. In order to avoid misleading future maintainers, this parameter is marked const. Signed-off-by: Stephen Warren Cc: Tejun Heo Cc: Will Drewry Cc: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe --- block/partitions/efi.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'block/partitions') diff --git a/block/partitions/efi.c b/block/partitions/efi.c index 6296b403c67a..b62fb88b8711 100644 --- a/block/partitions/efi.c +++ b/block/partitions/efi.c @@ -620,7 +620,6 @@ int efi_partition(struct parsed_partitions *state) gpt_entry *ptes = NULL; u32 i; unsigned ssz = bdev_logical_block_size(state->bdev) / 512; - u8 unparsed_guid[37]; if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) { kfree(gpt); @@ -649,11 +648,7 @@ int efi_partition(struct parsed_partitions *state) state->parts[i + 1].flags = ADDPART_FLAG_RAID; info = &state->parts[i + 1].info; - /* Instead of doing a manual swap to big endian, reuse the - * common ASCII hex format as the interim. - */ - efi_guid_unparse(&ptes[i].unique_partition_guid, unparsed_guid); - part_pack_uuid(unparsed_guid, info->uuid); + efi_guid_unparse(&ptes[i].unique_partition_guid, info->uuid); /* Naively convert UTF16-LE to 7 bits. */ label_max = min(sizeof(info->volname) - 1, -- cgit v1.2.3-70-g09d2 From d33b98fc82b0908e91fb05ae081acaed7323f9d2 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Thu, 8 Nov 2012 16:12:28 -0800 Subject: block: partition: msdos: provide UUIDs for partitions The MSDOS/MBR partition table includes a 32-bit unique ID, often referred to as the NT disk signature. When combined with a partition number within the table, this can form a unique ID similar in concept to EFI/GPT's partition UUID. Constructing and recording this value in struct partition_meta_info allows MSDOS partitions to be referred to on the kernel command-line using the following syntax: root=PARTUUID=0002dd75-01 Signed-off-by: Stephen Warren Cc: Tejun Heo Cc: Will Drewry Cc: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe --- block/partitions/msdos.c | 21 +++++++++++++++++++-- init/do_mounts.c | 4 ++++ 2 files changed, 23 insertions(+), 2 deletions(-) (limited to 'block/partitions') diff --git a/block/partitions/msdos.c b/block/partitions/msdos.c index 5f79a6677c69..8752a5d26565 100644 --- a/block/partitions/msdos.c +++ b/block/partitions/msdos.c @@ -94,6 +94,17 @@ static int aix_magic_present(struct parsed_partitions *state, unsigned char *p) return ret; } +static void set_info(struct parsed_partitions *state, int slot, + u32 disksig) +{ + struct partition_meta_info *info = &state->parts[slot].info; + + snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig, + slot); + info->volname[0] = 0; + state->parts[slot].has_info = true; +} + /* * Create devices for each logical partition in an extended partition. * The logical partitions form a linked list, with each entry being @@ -106,7 +117,8 @@ static int aix_magic_present(struct parsed_partitions *state, unsigned char *p) */ static void parse_extended(struct parsed_partitions *state, - sector_t first_sector, sector_t first_size) + sector_t first_sector, sector_t first_size, + u32 disksig) { struct partition *p; Sector sect; @@ -166,6 +178,7 @@ static void parse_extended(struct parsed_partitions *state, } put_partition(state, state->next, next, size); + set_info(state, state->next, disksig); if (SYS_IND(p) == LINUX_RAID_PARTITION) state->parts[state->next].flags = ADDPART_FLAG_RAID; loopct = 0; @@ -437,6 +450,7 @@ int msdos_partition(struct parsed_partitions *state) struct partition *p; struct fat_boot_sector *fb; int slot; + u32 disksig; data = read_part_sector(state, 0, §); if (!data) @@ -491,6 +505,8 @@ int msdos_partition(struct parsed_partitions *state) #endif p = (struct partition *) (data + 0x1be); + disksig = le32_to_cpup((__le32 *)(data + 0x1b8)); + /* * Look for partitions in two passes: * First find the primary and DOS-type extended partitions. @@ -515,11 +531,12 @@ int msdos_partition(struct parsed_partitions *state) put_partition(state, slot, start, n); strlcat(state->pp_buf, " <", PAGE_SIZE); - parse_extended(state, start, size); + parse_extended(state, start, size, disksig); strlcat(state->pp_buf, " >", PAGE_SIZE); continue; } put_partition(state, slot, start, size); + set_info(state, slot, disksig); if (SYS_IND(p) == LINUX_RAID_PARTITION) state->parts[slot].flags = ADDPART_FLAG_RAID; if (SYS_IND(p) == DM6_PARTITION) diff --git a/init/do_mounts.c b/init/do_mounts.c index c950d7c93f98..1d1b6348f903 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -189,6 +189,10 @@ done: * used when disk name of partitioned disk ends on a digit. * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the * unique id of a partition if the partition table provides it. + * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS + * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- + * filled hex representation of the 32-bit "NT disk signature", and PP + * is a zero-filled hex representation of the 1-based partition number. * 7) PARTUUID=/PARTNROFF= to select a partition in relation to * a partition with a known unique id. * -- cgit v1.2.3-70-g09d2