Allow the user to specify region_size. Ensure that the supplied value meets MD's constraints that the number of regions does not exceed 2^21. Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx> Index: linux-2.6/drivers/md/dm-raid.c =================================================================== --- linux-2.6.orig/drivers/md/dm-raid.c +++ linux-2.6/drivers/md/dm-raid.c @@ -51,7 +51,7 @@ struct raid_dev { #define DMPF_MAX_RECOVERY_RATE 0x20 #define DMPF_MAX_WRITE_BEHIND 0x40 #define DMPF_STRIPE_CACHE 0x80 - +#define DMPF_REGION_SIZE 0X100 struct raid_set { struct dm_target *ti; @@ -236,6 +236,65 @@ static int dev_parms(struct raid_set *rs } /* + * validate_region_size + * @rs + * @region_size: region size in sectors. If 0, pick a size (4MiB default) + * + * Set rs->md.bitmap_info.chunksize (which really refers to 'region size') + * Ensure that (ti->len/region_size < 2^21) - required by MD bitmap + * + * Returns: 0 on success, -EINVAL on failure + */ +static int validate_region_size(struct raid_set *rs, unsigned long region_size) +{ + unsigned long min_region_size = rs->ti->len / (1 << 21); + + if (!region_size) { + /* Pick a reasonable default - Math in sectors */ + + if (min_region_size > (1 << 13)) { + DMINFO("Choosing default region size of %lu sectors", + region_size); + rs->md.bitmap_info.chunksize = min_region_size; + } else { + DMINFO("Choosing default region size of 4MiB"); + rs->md.bitmap_info.chunksize = 1 << 13; /* sectors */ + } + } else { + /* User-supplied value - validate it */ + + if (region_size > rs->ti->len) { + rs->ti->error = "Supplied region size is too large"; + return -EINVAL; + } + + if (region_size < min_region_size) { + DMERR("Supplied region_size = %lu (Min = %lu)", + region_size, min_region_size); + rs->ti->error = "Supplied region size is too small"; + return -EINVAL; + } + + if (!is_power_of_2(region_size)) { + rs->ti->error = "Region size is not a power of 2"; + return -EINVAL; + } + + if (region_size < rs->md.chunk_sectors) { + rs->ti->error = "Region size is smaller than the chunk size"; + return -EINVAL; + } + rs->md.bitmap_info.chunksize = region_size; + } + + /* Convert to Bytes */ + rs->md.bitmap_info.chunksize <<= 9; + + return 0; +} + + +/* * Possible arguments are... * RAID456: * <chunk_size> [optional_args] @@ -248,12 +307,13 @@ static int dev_parms(struct raid_set *rs * [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization * [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 */ static int parse_raid_params(struct raid_set *rs, char **argv, unsigned num_raid_params) { unsigned i, rebuild_cnt = 0; - unsigned long value; + unsigned long value, region_size = 0; char *key; /* @@ -364,6 +424,9 @@ static int parse_raid_params(struct raid return -EINVAL; } rs->md.sync_speed_max = (int)value; + } else if (!strcmp(key, "region_size")) { + rs->print_flags |= DMPF_REGION_SIZE; + region_size = value; } else { DMERR("Unable to parse RAID parameter: %s", key); rs->ti->error = "Unable to parse RAID parameters"; @@ -371,6 +434,14 @@ static int parse_raid_params(struct raid } } + if (validate_region_size(rs, region_size)) + return -EINVAL; + + if (rs->md.chunk_sectors) + rs->ti->split_io = rs->md.chunk_sectors; + else + rs->ti->split_io = region_size; + /* Assume there are no metadata devices until the drives are parsed */ rs->md.persistent = 0; rs->md.external = 1; @@ -468,7 +539,6 @@ static int raid_ctr(struct dm_target *ti goto bad; INIT_WORK(&rs->md.event_work, do_table_event); - ti->split_io = rs->md.chunk_sectors; ti->private = rs; mutex_lock(&rs->md.reconfig_mutex); @@ -566,7 +636,6 @@ static int raid_status(struct dm_target DMEMIT(" sync"); if (rs->print_flags & DMPF_NOSYNC) DMEMIT(" nosync"); - for (i = 0; i < rs->md.raid_disks; i++) if ((rs->print_flags & DMPF_REBUILD) && rs->dev[i].data_dev && @@ -594,6 +663,9 @@ static int raid_status(struct dm_target DMEMIT(" stripe_cache %d", conf ? conf->max_nr_stripes * 2 : 0); } + if (rs->print_flags & DMPF_REGION_SIZE) + DMEMIT(" region_size %lu", + rs->md.bitmap_info.chunksize >> 9); DMEMIT(" %d", rs->md.raid_disks); for (i = 0; i < rs->md.raid_disks; i++) { Index: linux-2.6/Documentation/device-mapper/dm-raid.txt =================================================================== --- linux-2.6.orig/Documentation/device-mapper/dm-raid.txt +++ linux-2.6/Documentation/device-mapper/dm-raid.txt @@ -35,6 +35,9 @@ The possible parameters are as follows: [max_recovery_rate <kB/sec/disk>] Throttle RAID initialization [max_write_behind <sectors>] See '-write-behind=' (man mdadm) [stripe_cache <sectors>] Stripe cache size for higher RAIDs + [region_size <sectors>] Array_size / region_size = # of regions. A + region is the granularity at which the bitmap + tracks whether a device is in-sync or not. Line 3 contains the list of devices that compose the array in metadata/data device pairs. If the metadata is stored separately, a '-' -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel