md: expose the degraded status of an assembled array through sysfs
The 'degraded' attribute is useful to quickly determine if the array is
degraded, instead of parsing 'mdadm -D' output or relying on the other
techniques (number of working devices against number of defined devices,
etc.). The md code already keeps track of this attribute, so it's useful to
export it.
Signed-off-by: Iustin Pop <iusty@k1024.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 510625e..c059ae6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2833,6 +2833,12 @@
static struct md_sysfs_entry md_sync_max =
__ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
+static ssize_t
+degraded_show(mddev_t *mddev, char *page)
+{
+ return sprintf(page, "%d\n", mddev->degraded);
+}
+static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
static ssize_t
sync_speed_show(mddev_t *mddev, char *page)
@@ -2976,6 +2982,7 @@
&md_suspend_lo.attr,
&md_suspend_hi.attr,
&md_bitmap.attr,
+ &md_degraded.attr,
NULL,
};
static struct attribute_group md_redundancy_group = {