From e464eafdb4400c6d6576ba3840d8bd40340f8a96 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 27 Mar 2006 01:18:14 -0800 Subject: [PATCH] md: Support suspending of IO to regions of an md array 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/md.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'drivers/md/md.c') diff --git a/drivers/md/md.c b/drivers/md/md.c index a79dd33d343d..92fd0104fa04 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -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 = { -- cgit v1.2.1