File 0086-Manage-stop-improve-some-comments.patch of Package mdadm.5365
From 932be6276ee6a28ef64f11b260e0c9d3cafd6d4c Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 6 Jul 2015 13:37:19 +1000
Subject: [PATCH 120/359] Manage/stop: improve some comments.
References: bsc#1081910
This code always confuses me - this might help a bit.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Coly Li <colyli@suse.de>
---
Manage.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/Manage.c b/Manage.c
index aeb90dd..3930f4f 100644
--- a/Manage.c
+++ b/Manage.c
@@ -216,9 +216,6 @@ int Manage_stop(char *devname, int fd, int verbose, int will_retry)
return 1;
}
- /* If this is an mdmon managed array, just write 'inactive'
- * to the array state and let mdmon clear up.
- */
strcpy(devnm, fd2devnm(fd));
/* Get EXCL access first. If this fails, then attempting
* to stop is probably a bad idea.
@@ -242,6 +239,10 @@ int Manage_stop(char *devname, int fd, int verbose, int will_retry)
&& container[0]
&& mdmon_running(container)
&& count) {
+ /* Can't open, so something might be wrong. However it
+ * is a container, so we might be racing with mdmon, so
+ * retry for a bit.
+ */
if (fd >= 0)
close(fd);
flush_mdmon(container);
@@ -255,6 +256,9 @@ int Manage_stop(char *devname, int fd, int verbose, int will_retry)
devname);
return 1;
}
+ /* If this is an mdmon managed array, just write 'inactive'
+ * to the array state and let mdmon clear up.
+ */
if (mdi &&
mdi->array.level > 0 &&
is_subarray(mdi->text_version)) {
@@ -262,7 +266,7 @@ int Manage_stop(char *devname, int fd, int verbose, int will_retry)
/* This is mdmon managed. */
close(fd);
- /* As we have an O_EXCL open, any use of the device
+ /* As we had an O_EXCL open, any use of the device
* which blocks STOP_ARRAY is probably a transient use,
* so it is reasonable to retry for a while - 5 seconds.
*/
@@ -375,9 +379,20 @@ int Manage_stop(char *devname, int fd, int verbose, int will_retry)
size &= ~(chunk1-1);
size &= ~(chunk2-1);
/* rd1 must be smaller */
+ /* Reshape may have progressed further backwards than
+ * recorded, so target even further back (hence "-1")
+ */
position = (position / sectors - 1) * sectors;
+ /* rd1 is always the conversion factor between 'sync'
+ * position and 'reshape' position.
+ * We read 1 "new" stripe worth of data from where-ever,
+ * and when write out that full stripe.
+ */
sync_max = size - position/rd1;
} else {
+ /* Reshape will very likely be beyond position, and it may
+ * be too late to stop at '+1', so aim for '+2'
+ */
position = (position / sectors + 2) * sectors;
sync_max = position/rd1;
}
--
2.16.1
