From 63f33b8dda88923487004b20fba825486d009e7b Mon Sep 17 00:00:00 2001 From: Jonathan Brassow Date: Tue, 31 Jul 2012 21:44:26 -0500 Subject: DM RAID: Add support for MD RAID10 Support the MD RAID10 personality through dm-raid.c Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt index 946c733..1c18449 100644 --- a/Documentation/device-mapper/dm-raid.txt +++ b/Documentation/device-mapper/dm-raid.txt @@ -27,6 +27,10 @@ The target is named "raid" and it accepts the following parameters: - rotating parity N (right-to-left) with data restart raid6_nc RAID6 N continue - rotating parity N (right-to-left) with data continuation + raid10 Various RAID10 inspired algorithms chosen by additional params + - RAID10: Striped Mirrors (aka 'Striping on top of mirrors') + - RAID1E: Integrated Adjacent Stripe Mirroring + - and other similar RAID10 variants Reference: Chapter 4 of http://www.snia.org/sites/default/files/SNIA_DDF_Technical_Position_v2.0.pdf @@ -59,6 +63,28 @@ The target is named "raid" and it accepts the following parameters: logical size of the array. The bitmap records the device synchronisation state for each region. + [raid10_copies <# copies>] + [raid10_format near] + These two options are used to alter the default layout of + a RAID10 configuration. The number of copies is can be + specified, but the default is 2. There are other variations + to how the copies are laid down - the default and only current + option is "near". Near copies are what most people think of + with respect to mirroring. If these options are left + unspecified, or 'raid10_copies 2' and/or 'raid10_format near' + are given, then the layouts for 2, 3 and 4 devices are: + 2 drives 3 drives 4 drives + -------- ---------- -------------- + A1 A1 A1 A1 A2 A1 A1 A2 A2 + A2 A2 A2 A3 A3 A3 A3 A4 A4 + A3 A3 A4 A4 A5 A5 A5 A6 A6 + A4 A4 A5 A6 A6 A7 A7 A8 A8 + .. .. .. .. .. .. .. .. .. + The 2-device layout is equivalent 2-way RAID1. The 4-device + layout is what a traditional RAID10 would look like. The + 3-device layout is what might be called a 'RAID1E - Integrated + Adjacent Stripe Mirroring'. + <#raid_devs>: The number of devices composing the array. Each device consists of two entries. The first is the device containing the metadata (if any); the second is the one containing the diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index f4275a8..691b3c5 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -11,6 +11,7 @@ #include "md.h" #include "raid1.h" #include "raid5.h" +#include "raid10.h" #include "bitmap.h" #include @@ -52,7 +53,10 @@ 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 +#define DMPF_REGION_SIZE 0x100 +#define DMPF_RAID10_COPIES 0x200 +#define DMPF_RAID10_FORMAT 0x400 + struct raid_set { struct dm_target *ti; @@ -76,6 +80,7 @@ static struct raid_type { const unsigned algorithm; /* RAID algorithm. */ } raid_types[] = { {"raid1", "RAID1 (mirroring)", 0, 2, 1, 0 /* NONE */}, + {"raid10", "RAID10 (striped mirrors)", 0, 2, 10, UINT_MAX /* Varies */}, {"raid4", "RAID4 (dedicated parity disk)", 1, 2, 5, ALGORITHM_PARITY_0}, {"raid5_la", "RAID5 (left asymmetric)", 1, 2, 5, ALGORITHM_LEFT_ASYMMETRIC}, {"raid5_ra", "RAID5 (right asymmetric)", 1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC}, @@ -86,6 +91,17 @@ static struct raid_type { {"raid6_nc", "RAID6 (N continue)", 2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE} }; +static unsigned raid10_md_layout_to_copies(int layout) +{ + return layout & 0xFF; +} + +static int raid10_format_to_md_layout(char *format, unsigned copies) +{ + /* 1 "far" copy, and 'copies' "near" copies */ + return (1 << 8) | (copies & 0xFF); +} + static struct raid_type *get_raid_type(char *name) { int i; @@ -339,10 +355,16 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size) * [max_write_behind ] See '-write-behind=' (man mdadm) * [stripe_cache ] Stripe cache size for higher RAIDs * [region_size ] Defines granularity of bitmap + * + * RAID10-only options: + * [raid10_copies <# copies>] Number of copies. (Default: 2) + * [raid10_format ] Layout algorithm. (Default: near) */ static int parse_raid_params(struct raid_set *rs, char **argv, unsigned num_raid_params) { + char *raid10_format = "near"; + unsigned raid10_copies = 2; unsigned i, rebuild_cnt = 0; unsigned long value, region_size = 0; sector_t sectors_per_dev = rs->ti->len; @@ -416,11 +438,28 @@ static int parse_raid_params(struct raid_set *rs, char **argv, } key = argv[i++]; + + /* Parameters that take a string value are checked here. */ + if (!strcasecmp(key, "raid10_format")) { + if (rs->raid_type->level != 10) { + rs->ti->error = "'raid10_format' is an invalid parameter for this RAID type"; + return -EINVAL; + } + if (strcmp("near", argv[i])) { + rs->ti->error = "Invalid 'raid10_format' value given"; + return -EINVAL; + } + raid10_format = argv[i]; + rs->print_flags |= DMPF_RAID10_FORMAT; + continue; + } + if (strict_strtoul(argv[i], 10, &value) < 0) { rs->ti->error = "Bad numerical argument given in raid params"; return -EINVAL; } + /* Parameters that take a numeric value are checked here */ if (!strcasecmp(key, "rebuild")) { rebuild_cnt++; @@ -439,6 +478,7 @@ static int parse_raid_params(struct raid_set *rs, char **argv, return -EINVAL; } break; + case 10: default: DMERR("The rebuild parameter is not supported for %s", rs->raid_type->name); rs->ti->error = "Rebuild not supported for this RAID type"; @@ -495,7 +535,8 @@ static int parse_raid_params(struct raid_set *rs, char **argv, */ value /= 2; - if (rs->raid_type->level < 5) { + if ((rs->raid_type->level != 5) && + (rs->raid_type->level != 6)) { rs->ti->error = "Inappropriate argument: stripe_cache"; return -EINVAL; } @@ -520,6 +561,14 @@ static int parse_raid_params(struct raid_set *rs, char **argv, } else if (!strcasecmp(key, "region_size")) { rs->print_flags |= DMPF_REGION_SIZE; region_size = value; + } else if (!strcasecmp(key, "raid10_copies") && + (rs->raid_type->level == 10)) { + if ((value < 2) || (value > 0xFF)) { + rs->ti->error = "Bad value for 'raid10_copies'"; + return -EINVAL; + } + rs->print_flags |= DMPF_RAID10_COPIES; + raid10_copies = value; } else { DMERR("Unable to parse RAID parameter: %s", key); rs->ti->error = "Unable to parse RAID parameters"; @@ -538,8 +587,22 @@ static int parse_raid_params(struct raid_set *rs, char **argv, if (dm_set_target_max_io_len(rs->ti, max_io_len)) return -EINVAL; - if ((rs->raid_type->level > 1) && - sector_div(sectors_per_dev, (rs->md.raid_disks - rs->raid_type->parity_devs))) { + if (rs->raid_type->level == 10) { + if (raid10_copies > rs->md.raid_disks) { + rs->ti->error = "Not enough devices to satisfy specification"; + return -EINVAL; + } + + /* (Len * #mirrors) / #devices */ + sectors_per_dev = rs->ti->len * raid10_copies; + sector_div(sectors_per_dev, rs->md.raid_disks); + + rs->md.layout = raid10_format_to_md_layout(raid10_format, + raid10_copies); + rs->md.new_layout = rs->md.layout; + } else if ((rs->raid_type->level > 1) && + sector_div(sectors_per_dev, + (rs->md.raid_disks - rs->raid_type->parity_devs))) { rs->ti->error = "Target length not divisible by number of data devices"; return -EINVAL; } @@ -566,6 +629,9 @@ static int raid_is_congested(struct dm_target_callbacks *cb, int bits) if (rs->raid_type->level == 1) return md_raid1_congested(&rs->md, bits); + if (rs->raid_type->level == 10) + return md_raid10_congested(&rs->md, bits); + return md_raid5_congested(&rs->md, bits); } @@ -884,6 +950,9 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs) case 6: redundancy = rs->raid_type->parity_devs; break; + case 10: + redundancy = raid10_md_layout_to_copies(mddev->layout) - 1; + break; default: ti->error = "Unknown RAID type"; return -EINVAL; @@ -1049,12 +1118,19 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) goto bad; } + if (ti->len != rs->md.array_sectors) { + ti->error = "Array size does not match requested target length"; + ret = -EINVAL; + goto size_mismatch; + } rs->callbacks.congested_fn = raid_is_congested; dm_table_add_target_callbacks(ti->table, &rs->callbacks); mddev_suspend(&rs->md); return 0; +size_mismatch: + md_stop(&rs->md); bad: context_free(rs); @@ -1203,6 +1279,13 @@ static int raid_status(struct dm_target *ti, status_type_t type, DMEMIT(" region_size %lu", rs->md.bitmap_info.chunksize >> 9); + if (rs->print_flags & DMPF_RAID10_COPIES) + DMEMIT(" raid10_copies %u", + raid10_md_layout_to_copies(rs->md.layout)); + + if (rs->print_flags & DMPF_RAID10_FORMAT) + DMEMIT(" raid10_format near"); + DMEMIT(" %d", rs->md.raid_disks); for (i = 0; i < rs->md.raid_disks; i++) { if (rs->dev[i].meta_dev) @@ -1277,7 +1360,7 @@ static void raid_resume(struct dm_target *ti) static struct target_type raid_target = { .name = "raid", - .version = {1, 2, 0}, + .version = {1, 3, 0}, .module = THIS_MODULE, .ctr = raid_ctr, .dtr = raid_dtr, @@ -1304,6 +1387,8 @@ module_init(dm_raid_init); module_exit(dm_raid_exit); MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target"); +MODULE_ALIAS("dm-raid1"); +MODULE_ALIAS("dm-raid10"); MODULE_ALIAS("dm-raid4"); MODULE_ALIAS("dm-raid5"); MODULE_ALIAS("dm-raid6"); -- cgit v0.10.2