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/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt
index be4419a..a7d1c4a 100644
--- a/Documentation/device-mapper/dm-raid.txt
+++ b/Documentation/device-mapper/dm-raid.txt
@@ -50,6 +50,7 @@
[min_recovery_rate <kB/sec/disk>] Throttle RAID initialization
[max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
+ [write_mostly <idx>] Drive index is write-mostly
[max_write_behind <sectors>] See '-write-behind=' (man mdadm)
[stripe_cache <sectors>] Stripe cache size (higher RAIDs only)
[region_size <sectors>]
@@ -87,9 +88,10 @@
5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81
'dmsetup table' displays the table used to construct the mapping.
-The optional parameters will always be printed in the order listed
+The optional parameters are always printed in the order listed
above with "sync" or "nosync" always output ahead of the other
arguments, regardless of the order used when originally loading the table.
+Arguments that can be repeated are ordered by value.
'dmsetup status' yields information on the state and health of the
array.
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);