Enable external metadata arrays to manage rebuild checkpointing via a
md/recovery_start attribute that overrides rdev->recovery_offset.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
Documentation/md.txt | 15 +++++++++--
drivers/md/md.c | 69 +++++++++++++++++++++++++++++++++++++++++++-------
drivers/md/md.h | 1 +
3 files changed, 72 insertions(+), 13 deletions(-)
diff --git a/Documentation/md.txt b/Documentation/md.txt
index 4edd39e..2b03814 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -233,9 +233,18 @@ All md devices contain:
resync_start
The point at which resync should start. If no resync is needed,
- this will be a very large number. At array creation it will
- default to 0, though starting the array as 'clean' will
- set it much larger.
+ this will be a very large number (or 'none' since 2.6.30-rc1). At
+ array creation it will default to 0, though starting the array as
+ 'clean' will set it much larger.
+
+ recovery_start
+ The point at which recovery should start when rebuilding a degraded
+ array member. This value overrides the 'recovery_offset' read from
+ the metadata. Setting this value to zero tells md to use/report
+ the default recovery_offset read from the metadata. This value
+ auto-resets itself to zero (default recovery_offset) after it has
+ been consumed by the recovery process. This value cannot be
+ changed while a recovery is in-flight.
new_dev
This file can be written but not read. The value written should
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3e8fb67..5f09d40 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2983,6 +2983,56 @@ resync_start_store(mddev_t *mddev, const char *buf, size_t len)
static struct md_sysfs_entry md_resync_start =
__ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
+static sector_t md_recovery_offset(mddev_t *mddev)
+{
+ /* this is sometimes called outside mddev_lock() hence the
+ * rcu_read_lock()
+ */
+ sector_t recovery_offset = MaxSector;
+ mdk_rdev_t *rdev;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
+ if (rdev->raid_disk >= 0 &&
+ !test_bit(Faulty, &rdev->flags) &&
+ !test_bit(In_sync, &rdev->flags) &&
+ rdev->recovery_offset < recovery_offset)
+ recovery_offset = rdev->recovery_offset;
+ rcu_read_unlock();
+
+ return recovery_offset;
+}
+
+static ssize_t recovery_start_show(mddev_t *mddev, char *page)
+{
+ unsigned long long recovery_start = mddev->recovery_start;
+
+ if (recovery_start == 0)
+ recovery_start = md_recovery_offset(mddev);
+
+ if (recovery_start == MaxSector)
+ return sprintf(page, "none\n");
+
+ return sprintf(page, "%llu\n", recovery_start);
+}
+
+static ssize_t recovery_start_store(mddev_t *mddev, const char *buf, size_t len)
+{
+ unsigned long long recovery_start;
+
+ if (strict_strtoull(buf, 10, &recovery_start))
+ return -EINVAL;
+
+ if (!mddev->ro || !mddev->degraded || md_recovery_offset(mddev) > 0)
+ return -EBUSY;
+
+ mddev->recovery_start = recovery_start;
+ return len;
+}
+
+static struct md_sysfs_entry md_recovery_start =
+__ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
+
/*
* The array state can be:
*
@@ -3788,6 +3838,7 @@ static struct attribute *md_default_attrs[] = {
&md_chunk_size.attr,
&md_size.attr,
&md_resync_start.attr,
+ &md_recovery_start.attr,
&md_metadata.attr,
&md_new_device.attr,
&md_safe_delay.attr,
@@ -4426,6 +4477,7 @@ out:
mddev->dev_sectors = 0;
mddev->raid_disks = 0;
mddev->recovery_cp = 0;
+ mddev->recovery_start = 0;
mddev->resync_min = 0;
mddev->resync_max = MaxSector;
mddev->reshape_position = MaxSector;
@@ -6338,18 +6390,15 @@ void md_do_sync(mddev_t *mddev)
} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
max_sectors = mddev->dev_sectors;
- else {
+ else if (mddev->recovery_start) {
+ /* userspace requested override of rdev->recovery_offset */
+ max_sectors = mddev->dev_sectors;
+ j = mddev->recovery_start;
+ mddev->recovery_start = 0;
+ } else {
/* recovery follows the physical size of devices */
max_sectors = mddev->dev_sectors;
- j = MaxSector;
- rcu_read_lock();
- list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
- if (rdev->raid_disk >= 0 &&
- !test_bit(Faulty, &rdev->flags) &&
- !test_bit(In_sync, &rdev->flags) &&
- rdev->recovery_offset < j)
- j = rdev->recovery_offset;
- rcu_read_unlock();
+ j = md_recovery_offset(mddev);
}
printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
diff --git a/drivers/md/md.h b/drivers/md/md.h
index f184b69..03a18b4 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -252,6 +252,7 @@ struct mddev_s
atomic_t recovery_active; /* blocks scheduled, but not written */
wait_queue_head_t recovery_wait;
sector_t recovery_cp;
+ sector_t recovery_start; /* override rdev->recovery_offset */
sector_t resync_min; /* user requested sync
* starts here */
sector_t resync_max; /* resync should pause
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