dm raid: add write_mostly parameter
Add the write_mostly parameter to RAID1 dm-raid tables.
This allows the user to set the WriteMostly flag on a RAID1 device that
should normally be avoided for read I/O.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index a8a1915..88143a0 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -308,6 +308,7 @@
* [daemon_sleep <ms>] Time between bitmap daemon work to clear bits
* [min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
* [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
+ * [write_mostly <idx>] Indicate a write mostly drive via index
* [max_write_behind <sectors>] See '-write-behind=' (man mdadm)
* [stripe_cache <sectors>] Stripe cache size for higher RAIDs
* [region_size <sectors>] Defines granularity of bitmap
@@ -376,7 +377,21 @@
clear_bit(In_sync, &rs->dev[value].rdev.flags);
rs->dev[value].rdev.recovery_offset = 0;
rs->print_flags |= DMPF_REBUILD;
+ } else if (!strcasecmp(key, "write_mostly")) {
+ if (rs->raid_type->level != 1) {
+ rs->ti->error = "write_mostly option is only valid for RAID1";
+ return -EINVAL;
+ }
+ if (value > rs->md.raid_disks) {
+ rs->ti->error = "Invalid write_mostly drive index given";
+ return -EINVAL;
+ }
+ set_bit(WriteMostly, &rs->dev[value].rdev.flags);
} else if (!strcasecmp(key, "max_write_behind")) {
+ if (rs->raid_type->level != 1) {
+ rs->ti->error = "max_write_behind option is only valid for RAID1";
+ return -EINVAL;
+ }
rs->print_flags |= DMPF_MAX_WRITE_BEHIND;
/*
@@ -621,11 +636,15 @@
break;
case STATUSTYPE_TABLE:
/* The string you would use to construct this array */
- for (i = 0; i < rs->md.raid_disks; i++)
+ for (i = 0; i < rs->md.raid_disks; i++) {
if ((rs->print_flags & DMPF_REBUILD) &&
rs->dev[i].data_dev &&
!test_bit(In_sync, &rs->dev[i].rdev.flags))
raid_param_cnt += 2; /* for rebuilds */
+ if (rs->dev[i].data_dev &&
+ test_bit(WriteMostly, &rs->dev[i].rdev.flags))
+ raid_param_cnt += 2;
+ }
raid_param_cnt += (hweight64(rs->print_flags & ~DMPF_REBUILD) * 2);
if (rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC))
@@ -656,6 +675,11 @@
if (rs->print_flags & DMPF_MAX_RECOVERY_RATE)
DMEMIT(" max_recovery_rate %d", rs->md.sync_speed_max);
+ for (i = 0; i < rs->md.raid_disks; i++)
+ if (rs->dev[i].data_dev &&
+ test_bit(WriteMostly, &rs->dev[i].rdev.flags))
+ DMEMIT(" write_mostly %u", i);
+
if (rs->print_flags & DMPF_MAX_WRITE_BEHIND)
DMEMIT(" max_write_behind %lu",
rs->md.bitmap_info.max_write_behind);