dm raid: add region_size parameter
Allow the user to specify the region_size. Ensures that the supplied value meets md's constraints, viz. the number of regions does not exceed 2^21. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow
Alasdair G Kergon
parent
c0a2fa1ef1
commit
c1084561bb
2 changed files with 83 additions and 3 deletions
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@ -52,6 +52,10 @@ The target is named "raid" and it accepts the following parameters:
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[max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
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[max_write_behind <sectors>] See '-write-behind=' (man mdadm)
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[stripe_cache <sectors>] Stripe cache size (higher RAIDs only)
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[region_size <sectors>]
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The region_size multiplied by the number of regions is the
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logical size of the array. The bitmap records the device
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synchronisation state for each region.
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<#raid_devs>: The number of devices composing the array.
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Each device consists of two entries. The first is the device
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@ -52,7 +52,7 @@ struct raid_dev {
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#define DMPF_MAX_RECOVERY_RATE 0x20
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#define DMPF_MAX_WRITE_BEHIND 0x40
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#define DMPF_STRIPE_CACHE 0x80
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#define DMPF_REGION_SIZE 0X100
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struct raid_set {
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struct dm_target *ti;
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@ -236,6 +236,67 @@ static int dev_parms(struct raid_set *rs, char **argv)
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return 0;
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}
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/*
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* validate_region_size
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* @rs
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* @region_size: region size in sectors. If 0, pick a size (4MiB default).
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*
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* Set rs->md.bitmap_info.chunksize (which really refers to 'region size').
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* Ensure that (ti->len/region_size < 2^21) - required by MD bitmap.
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*
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* Returns: 0 on success, -EINVAL on failure.
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*/
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static int validate_region_size(struct raid_set *rs, unsigned long region_size)
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{
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unsigned long min_region_size = rs->ti->len / (1 << 21);
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if (!region_size) {
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/*
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* Choose a reasonable default. All figures in sectors.
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*/
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if (min_region_size > (1 << 13)) {
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DMINFO("Choosing default region size of %lu sectors",
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region_size);
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region_size = min_region_size;
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} else {
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DMINFO("Choosing default region size of 4MiB");
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region_size = 1 << 13; /* sectors */
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}
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} else {
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/*
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* Validate user-supplied value.
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*/
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if (region_size > rs->ti->len) {
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rs->ti->error = "Supplied region size is too large";
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return -EINVAL;
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}
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if (region_size < min_region_size) {
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DMERR("Supplied region_size (%lu sectors) below minimum (%lu)",
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region_size, min_region_size);
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rs->ti->error = "Supplied region size is too small";
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return -EINVAL;
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}
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if (!is_power_of_2(region_size)) {
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rs->ti->error = "Region size is not a power of 2";
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return -EINVAL;
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}
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if (region_size < rs->md.chunk_sectors) {
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rs->ti->error = "Region size is smaller than the chunk size";
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return -EINVAL;
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}
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}
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/*
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* Convert sectors to bytes.
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*/
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rs->md.bitmap_info.chunksize = (region_size << 9);
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return 0;
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}
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/*
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* Possible arguments are...
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* RAID456:
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@ -249,12 +310,13 @@ static int dev_parms(struct raid_set *rs, char **argv)
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* [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization
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* [max_write_behind <sectors>] See '-write-behind=' (man mdadm)
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* [stripe_cache <sectors>] Stripe cache size for higher RAIDs
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* [region_size <sectors>] Defines granularity of bitmap
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*/
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static int parse_raid_params(struct raid_set *rs, char **argv,
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unsigned num_raid_params)
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{
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unsigned i, rebuild_cnt = 0;
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unsigned long value;
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unsigned long value, region_size = 0;
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char *key;
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/*
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@ -365,6 +427,9 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
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return -EINVAL;
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}
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rs->md.sync_speed_max = (int)value;
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} else if (!strcasecmp(key, "region_size")) {
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rs->print_flags |= DMPF_REGION_SIZE;
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region_size = value;
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} else {
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DMERR("Unable to parse RAID parameter: %s", key);
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rs->ti->error = "Unable to parse RAID parameters";
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@ -372,6 +437,14 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
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}
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}
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if (validate_region_size(rs, region_size))
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return -EINVAL;
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if (rs->md.chunk_sectors)
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rs->ti->split_io = rs->md.chunk_sectors;
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else
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rs->ti->split_io = region_size;
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/* Assume there are no metadata devices until the drives are parsed */
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rs->md.persistent = 0;
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rs->md.external = 1;
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@ -469,7 +542,6 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
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goto bad;
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INIT_WORK(&rs->md.event_work, do_table_event);
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ti->split_io = rs->md.chunk_sectors;
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ti->private = rs;
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mutex_lock(&rs->md.reconfig_mutex);
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@ -596,6 +668,10 @@ static int raid_status(struct dm_target *ti, status_type_t type,
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conf ? conf->max_nr_stripes * 2 : 0);
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}
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if (rs->print_flags & DMPF_REGION_SIZE)
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DMEMIT(" region_size %lu",
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rs->md.bitmap_info.chunksize >> 9);
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DMEMIT(" %d", rs->md.raid_disks);
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for (i = 0; i < rs->md.raid_disks; i++) {
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DMEMIT(" -"); /* metadata device */
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