md: Fix unfortunate interaction with evms
evms configures md arrays by:
open device
send ioctl
close device
for each different ioctl needed.
Since 2.6.29, the device can disappear after the 'close'
unless a significant configuration has happened to the device.
The change made by "SET_ARRAY_INFO" can too minor to stop the device
from disappearing, but important enough that losing the change is bad.
So: make sure SET_ARRAY_INFO sets mddev->ctime, and keep the device
active as long as ctime is non-zero (it gets zeroed with lots of other
things when the array is stopped).
This is suitable for -stable kernels since 2.6.29.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f4f5f82..7862231 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -386,7 +386,9 @@
if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
return;
if (!mddev->raid_disks && list_empty(&mddev->disks) &&
- !mddev->hold_active) {
+ mddev->ctime == 0 && !mddev->hold_active) {
+ /* Array is not configured at all, and not held active,
+ * so destroy it */
list_del(&mddev->all_mddevs);
if (mddev->gendisk) {
/* we did a probe so need to clean up.
@@ -5262,6 +5264,10 @@
mddev->minor_version = info->minor_version;
mddev->patch_version = info->patch_version;
mddev->persistent = !info->not_persistent;
+ /* ensure mddev_put doesn't delete this now that there
+ * is some minimal configuration.
+ */
+ mddev->ctime = get_seconds();
return 0;
}
mddev->major_version = MD_MAJOR_VERSION;