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[PATCH] md: Support suspending of IO to regions of an md array

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This allows user-space to access data safely.  This is needed for raid5
reshape as user-space needs to take a backup of the first few stripes before
allowing reshape to commence.

It will also be useful in cluster-aware raid1 configurations so that all
cluster members can leave a section of the array untouched while a
resync/recovery happens.

A 'start' and 'end' of the suspended range are written to 2 sysfs attributes.
Note that only one range can be suspended at a time.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
NeilBrown
2006-03-27 01:18:14 -08:00
committed by Linus Torvalds
parent 16484bf596
commit e464eafdb4
3 changed files with 77 additions and 0 deletions
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59
drivers/md/md.c
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@@ -2365,6 +2365,63 @@ sync_completed_show(mddev_t *mddev, char *page)
static struct md_sysfs_entry
md_sync_completed = __ATTR_RO(sync_completed);
static ssize_t
suspend_lo_show(mddev_t *mddev, char *page)
{
return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
}
static ssize_t
suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
if (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->pers->quiesce(mddev, 2);
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);
static ssize_t
suspend_hi_show(mddev_t *mddev, char *page)
{
return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
}
static ssize_t
suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
if (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->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);
static struct attribute *md_default_attrs[] = {
&md_level.attr,
&md_raid_disks.attr,
@@ -2382,6 +2439,8 @@ static struct attribute *md_redundancy_attrs[] = {
&md_sync_max.attr,
&md_sync_speed.attr,
&md_sync_completed.attr,
&md_suspend_lo.attr,
&md_suspend_hi.attr,
NULL,
};
static struct attribute_group md_redundancy_group = {