From 23ddff3792f61193695114c68d6ebd57e974c4f8 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 14 Jan 2011 09:14:34 +1100
Subject: [PATCH] md: allow suspend_lo and suspend_hi to decrease as well as
increase.
The sysfs attributes 'suspend_lo' and 'suspend_hi' describe a region
to which read/writes are suspended so that the under lying data can be
manipulated without user-space noticing.
Currently the window they describe can only move forwards along the
device. However this is an unnecessary restriction which will cause
problems with planned developments.
So relax this restriction and allow these endpoints to move
arbitrarily.
Signed-off-by: NeilBrown <neilb@suse.de>
---
drivers/md/md.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 42b1d9ead7f2b..dd64ad30a0fe0 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4016,19 +4016,24 @@ suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
+ unsigned long long old = mddev->suspend_lo;
if (mddev->pers == NULL ||
mddev->pers->quiesce == NULL)
return -EINVAL;
if (buf == e || (*e && *e != '\n'))
return -EINVAL;
- if (new >= mddev->suspend_hi ||
- (new > mddev->suspend_lo && new < mddev->suspend_hi)) {
- mddev->suspend_lo = new;
+
+ mddev->suspend_lo = new;
+ if (new >= old)
+ /* Shrinking suspended region */
mddev->pers->quiesce(mddev, 2);
- return len;
- } else
- return -EINVAL;
+ else {
+ /* Expanding suspended region - need to wait */
+ mddev->pers->quiesce(mddev, 1);
+ mddev->pers->quiesce(mddev, 0);
+ }
+ return len;
}
static struct md_sysfs_entry md_suspend_lo =
__ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
@@ -4045,20 +4050,24 @@ suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
+ unsigned long long old = mddev->suspend_hi;
if (mddev->pers == NULL ||
mddev->pers->quiesce == NULL)
return -EINVAL;
if (buf == e || (*e && *e != '\n'))
return -EINVAL;
- if ((new <= mddev->suspend_lo && mddev->suspend_lo >= mddev->suspend_hi) ||
- (new > mddev->suspend_lo && new > mddev->suspend_hi)) {
- mddev->suspend_hi = new;
+
+ mddev->suspend_hi = new;
+ if (new <= old)
+ /* Shrinking suspended region */
+ mddev->pers->quiesce(mddev, 2);
+ else {
+ /* Expanding suspended region - need to wait */
mddev->pers->quiesce(mddev, 1);
mddev->pers->quiesce(mddev, 0);
- return len;
- } else
- return -EINVAL;
+ }
+ return len;
}
static struct md_sysfs_entry md_suspend_hi =
__ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
--
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