From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Both most common formats have uuid in addition to partition name: GPT: standard uuid xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx DOS: 4 byte disk signature and 1 byte partition xxxxxxxx-xx Tools from util-linux use the same notation for them. Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Reviewed-by: Kyle Fortin <kyle.fortin@xxxxxxxxxx> [dianders: rebased to modern kernels] Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxx> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> --- I found myself needing the PARTUUID from userspace recently and it seems like pretty much all of the solutions involve a lot of code or including some userspace libraries to solve this for you. This is less than ideal when you're running from an initrd and want to keep things simple. Given that the kernel has PARTUUID handling already and needs to keep track of it for using it in "root=" matching, it seems silly not to expose it, so I wrote a patch for it. After I wrote the 2 line patch to expose the UUID, I thought to search the internet and found an old patch where someone had written what amounts to the same two lines [1], so I'm grabbing the old patch and resending as a v2. I'm keeping the Reviewed-by even though I rebased the patch (adjusted for file moves / name changes) since it's a tiny patch and the concept is identical to the old patch. Crossing my fingers that this looks OK to land. [1] https://lore.kernel.org/r/150729013610.744480.1644359289262914898.stgit@buzz Changes in v2: - Rebased block/partitions/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/partitions/core.c b/block/partitions/core.c index 5bd7a603092e..aa54c1f4eaa5 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -253,6 +253,8 @@ static int part_uevent(const struct device *dev, struct kobj_uevent_env *env) add_uevent_var(env, "PARTN=%u", bdev_partno(part)); if (part->bd_meta_info && part->bd_meta_info->volname[0]) add_uevent_var(env, "PARTNAME=%s", part->bd_meta_info->volname); + if (part->bd_meta_info && part->bd_meta_info->uuid[0]) + add_uevent_var(env, "PARTUUID=%s", part->bd_meta_info->uuid); return 0; } -- 2.47.0.rc0.187.ge670bccf7e-goog
