Commit 23ddff37 authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.de>
parent 75d3da43

drivers/md/md.c

+21 −12
Original line number Diff line number Diff line
@@ -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;

	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;

}

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;

	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;

}

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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