From: Sebastian Parschauer <s.parschauer@xxxxxx>
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: Sebastian Parschauer <s.parschauer@xxxxxx>
[Guoqing: mention the change in md.rst]
Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
---
Documentation/admin-guide/md.rst | 4 ++++
drivers/md/md.c | 9 +++++++++
2 files changed, 13 insertions(+)
diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst
index d973d469ffc4..cc8781b96b4d 100644
--- a/Documentation/admin-guide/md.rst
+++ b/Documentation/admin-guide/md.rst
@@ -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::
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ea48bc25cce1..0c2a0e65b4f1 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4225,6 +4225,14 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
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)
{
@@ -5481,6 +5489,7 @@ 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,
--
2.17.1
