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authorStephen Warren <swarren@nvidia.com>2012-11-08 16:12:28 -0800
committerJens Axboe <axboe@kernel.dk>2012-11-23 14:28:58 +0100
commitd33b98fc82b0908e91fb05ae081acaed7323f9d2 (patch)
treefe5803ac8510ab46f0fcbcc1712343806699a5cb /init/do_mounts.c
parent283f8fc03927b0ef42a2faa60a0df5ec8c612edb (diff)
downloadlinux-aarch64-d33b98fc82b0908e91fb05ae081acaed7323f9d2.tar.gz
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 <swarren@nvidia.com> Cc: Tejun Heo <tj@kernel.org> Cc: Will Drewry <wad@chromium.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'init/do_mounts.c')
-rw-r--r--init/do_mounts.c4
1 files changed, 4 insertions, 0 deletions
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=<UUID>/PARTNROFF=<int> to select a partition in relation to
* a partition with a known unique id.
*