DM RAID: Add support for MD RAID10 (63f33b8d) · Commits · e / devices / android_kernel_fairphone_FP5

Documentation/device-mapper/dm-raid.txt

+26 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/md/dm-raid.c

+90 −5

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#include "md.h"
		#include "raid1.h"
		#include "raid5.h"
		#include "raid10.h"
		#include "bitmap.h"

		#include <linux/device-mapper.h>
		@@ -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 <sectors>] See '-write-behind=' (man mdadm)
		* [stripe_cache <sectors>] Stripe cache size for higher RAIDs
		* [region_size <sectors>] Defines granularity of bitmap
		*
		* RAID10-only options:
		* [raid10_copies <# copies>] Number of copies. (Default: 2)
		* [raid10_format <near>] 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");