Commit ec164d07 authored by Sebastian Parschauer's avatar Sebastian Parschauer Committed by Song Liu
Browse files

md: register new md sysfs file 'uuid' read-only 



Report the UUID of the MD array in the following format:
xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

This is useful if you don't want to wait for udev to identify array.
And it is also easy for script to monitor it with the format.

Signed-off-by: default avatarSebastian Parschauer <s.parschauer@gmx.de>
[Guoqing: mention the change in md.rst]
Signed-off-by: default avatarGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent d9c0fa50

Documentation/admin-guide/md.rst

+4 −0
Original line number Diff line number Diff line
@@ -426,6 +426,10 @@ All md devices contain: 
     The accepted values when writing to this file are ``ppl`` and ``resync``,

     used to enable and disable PPL.



  uuid

     This indicates the UUID of the array in the following format:

     xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx





As component devices are added to an md array, they appear in the ``md``

directory as new directories named::

drivers/md/md.c

+9 −0
Original line number Diff line number Diff line
@@ -4252,6 +4252,14 @@ out_unlock: 
static struct md_sysfs_entry md_raid_disks =

__ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);



static ssize_t

uuid_show(struct mddev *mddev, char *page)

{

	return sprintf(page, "%pU\n", mddev->uuid);

}

static struct md_sysfs_entry md_uuid =

__ATTR(uuid, S_IRUGO, uuid_show, NULL);



static ssize_t

chunk_size_show(struct mddev *mddev, char *page)

{
@@ -5508,6 +5516,7 @@ static struct attribute *md_default_attrs[] = { 
	&md_level.attr,

	&md_layout.attr,

	&md_raid_disks.attr,

	&md_uuid.attr,

	&md_chunk_size.attr,

	&md_size.attr,

	&md_resync_start.attr,

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