1 files changed, 517 insertions, 67 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 86cb7e5d83d..4880b69e2e9 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 <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 +91,46 @@ static struct raid_type {
 	{"raid6_nc", "RAID6 (N continue)",		2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
 };
 
+static char *raid10_md_layout_to_format(int layout)
+{
+	/*
+	 * Bit 16 and 17 stand for "offset" and "use_far_sets"
+	 * Refer to MD's raid10.c for details
+	 */
+	if ((layout & 0x10000) && (layout & 0x20000))
+		return "offset";
+
+	if ((layout & 0xFF) > 1)
+		return "near";
+
+	return "far";
+}
+
+static unsigned raid10_md_layout_to_copies(int layout)
+{
+	if ((layout & 0xFF) > 1)
+		return layout & 0xFF;
+	return (layout >> 8) & 0xFF;
+}
+
+static int raid10_format_to_md_layout(char *format, unsigned copies)
+{
+	unsigned n = 1, f = 1;
+
+	if (!strcmp("near", format))
+		n = copies;
+	else
+		f = copies;
+
+	if (!strcmp("offset", format))
+		return 0x30000 | (f << 8) | n;
+
+	if (!strcmp("far", format))
+		return 0x20000 | (f << 8) | n;
+
+	return (f << 8) | n;
+}
+
 static struct raid_type *get_raid_type(char *name)
 {
 	int i;
@@ -101,20 +146,12 @@ static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *ra
 {
 	unsigned i;
 	struct raid_set *rs;
-	sector_t sectors_per_dev;
 
 	if (raid_devs <= raid_type->parity_devs) {
 		ti->error = "Insufficient number of devices";
 		return ERR_PTR(-EINVAL);
 	}
 
-	sectors_per_dev = ti->len;
-	if ((raid_type->level > 1) &&
-	    sector_div(sectors_per_dev, (raid_devs - raid_type->parity_devs))) {
-		ti->error = "Target length not divisible by number of data devices";
-		return ERR_PTR(-EINVAL);
-	}
-
 	rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]), GFP_KERNEL);
 	if (!rs) {
 		ti->error = "Cannot allocate raid context";
@@ -128,7 +165,6 @@ static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *ra
 	rs->md.raid_disks = raid_devs;
 	rs->md.level = raid_type->level;
 	rs->md.new_level = rs->md.level;
-	rs->md.dev_sectors = sectors_per_dev;
 	rs->md.layout = raid_type->algorithm;
 	rs->md.new_layout = rs->md.layout;
 	rs->md.delta_disks = 0;
@@ -143,6 +179,7 @@ static struct raid_set *context_alloc(struct dm_target *ti, struct raid_type *ra
 	 *  rs->md.external
 	 *  rs->md.chunk_sectors
 	 *  rs->md.new_chunk_sectors
+	 *  rs->md.dev_sectors
 	 */
 
 	return rs;
@@ -155,10 +192,7 @@ static void context_free(struct raid_set *rs)
 	for (i = 0; i < rs->md.raid_disks; i++) {
 		if (rs->dev[i].meta_dev)
 			dm_put_device(rs->ti, rs->dev[i].meta_dev);
-		if (rs->dev[i].rdev.sb_page)
-			put_page(rs->dev[i].rdev.sb_page);
-		rs->dev[i].rdev.sb_page = NULL;
-		rs->dev[i].rdev.sb_loaded = 0;
+		md_rdev_clear(&rs->dev[i].rdev);
 		if (rs->dev[i].data_dev)
 			dm_put_device(rs->ti, rs->dev[i].data_dev);
 	}
@@ -290,9 +324,11 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 		 * Choose a reasonable default.  All figures in sectors.
 		 */
 		if (min_region_size > (1 << 13)) {
+			/* If not a power of 2, make it the next power of 2 */
+			if (min_region_size & (min_region_size - 1))
+				region_size = 1 << fls(region_size);
 			DMINFO("Choosing default region size of %lu sectors",
 			       region_size);
-			region_size = min_region_size;
 		} else {
 			DMINFO("Choosing default region size of 4MiB");
 			region_size = 1 << 13; /* sectors */
@@ -333,6 +369,104 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size)
 }
 
 /*
+ * validate_raid_redundancy
+ * @rs
+ *
+ * Determine if there are enough devices in the array that haven't
+ * failed (or are being rebuilt) to form a usable array.
+ *
+ * Returns: 0 on success, -EINVAL on failure.
+ */
+static int validate_raid_redundancy(struct raid_set *rs)
+{
+	unsigned i, rebuild_cnt = 0;
+	unsigned rebuilds_per_group = 0, copies, d;
+	unsigned group_size, last_group_start;
+
+	for (i = 0; i < rs->md.raid_disks; i++)
+		if (!test_bit(In_sync, &rs->dev[i].rdev.flags) ||
+		    !rs->dev[i].rdev.sb_page)
+			rebuild_cnt++;
+
+	switch (rs->raid_type->level) {
+	case 1:
+		if (rebuild_cnt >= rs->md.raid_disks)
+			goto too_many;
+		break;
+	case 4:
+	case 5:
+	case 6:
+		if (rebuild_cnt > rs->raid_type->parity_devs)
+			goto too_many;
+		break;
+	case 10:
+		copies = raid10_md_layout_to_copies(rs->md.layout);
+		if (rebuild_cnt < copies)
+			break;
+
+		/*
+		 * It is possible to have a higher rebuild count for RAID10,
+		 * as long as the failed devices occur in different mirror
+		 * groups (i.e. different stripes).
+		 *
+		 * When checking "near" format, make sure no adjacent devices
+		 * have failed beyond what can be handled.  In addition to the
+		 * simple case where the number of devices is a multiple of the
+		 * number of copies, we must also handle cases where the number
+		 * of devices is not a multiple of the number of copies.
+		 * E.g.    dev1 dev2 dev3 dev4 dev5
+		 *          A    A    B    B    C
+		 *          C    D    D    E    E
+		 */
+		if (!strcmp("near", raid10_md_layout_to_format(rs->md.layout))) {
+			for (i = 0; i < rs->md.raid_disks * copies; i++) {
+				if (!(i % copies))
+					rebuilds_per_group = 0;
+				d = i % rs->md.raid_disks;
+				if ((!rs->dev[d].rdev.sb_page ||
+				     !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
+				    (++rebuilds_per_group >= copies))
+					goto too_many;
+			}
+			break;
+		}
+
+		/*
+		 * When checking "far" and "offset" formats, we need to ensure
+		 * that the device that holds its copy is not also dead or
+		 * being rebuilt.  (Note that "far" and "offset" formats only
+		 * support two copies right now.  These formats also only ever
+		 * use the 'use_far_sets' variant.)
+		 *
+		 * This check is somewhat complicated by the need to account
+		 * for arrays that are not a multiple of (far) copies.  This
+		 * results in the need to treat the last (potentially larger)
+		 * set differently.
+		 */
+		group_size = (rs->md.raid_disks / copies);
+		last_group_start = (rs->md.raid_disks / group_size) - 1;
+		last_group_start *= group_size;
+		for (i = 0; i < rs->md.raid_disks; i++) {
+			if (!(i % copies) && !(i > last_group_start))
+				rebuilds_per_group = 0;
+			if ((!rs->dev[i].rdev.sb_page ||
+			     !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
+			    (++rebuilds_per_group >= copies))
+					goto too_many;
+		}
+		break;
+	default:
+		if (rebuild_cnt)
+			return -EINVAL;
+	}
+
+	return 0;
+
+too_many:
+	return -EINVAL;
+}
+
+/*
  * Possible arguments are...
  *	<chunk_size> [optional_args]
  *
@@ -350,19 +484,27 @@ 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|far|offset>] Layout algorithm.  (Default: near)
  */
 static int parse_raid_params(struct raid_set *rs, char **argv,
 			     unsigned num_raid_params)
 {
-	unsigned i, rebuild_cnt = 0;
+	char *raid10_format = "near";
+	unsigned raid10_copies = 2;
+	unsigned i;
 	unsigned long value, region_size = 0;
+	sector_t sectors_per_dev = rs->ti->len;
+	sector_t max_io_len;
 	char *key;
 
 	/*
 	 * First, parse the in-order required arguments
 	 * "chunk_size" is the only argument of this type.
 	 */
-	if ((strict_strtoul(argv[0], 10, &value) < 0)) {
+	if ((kstrtoul(argv[0], 10, &value) < 0)) {
 		rs->ti->error = "Bad chunk size";
 		return -EINVAL;
 	} else if (rs->raid_type->level == 1) {
@@ -425,21 +567,32 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 		}
 
 		key = argv[i++];
-		if (strict_strtoul(argv[i], 10, &value) < 0) {
+
+		/* 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]) &&
+			    strcmp("far", argv[i]) &&
+			    strcmp("offset", argv[i])) {
+				rs->ti->error = "Invalid 'raid10_format' value given";
+				return -EINVAL;
+			}
+			raid10_format = argv[i];
+			rs->print_flags |= DMPF_RAID10_FORMAT;
+			continue;
+		}
+
+		if (kstrtoul(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++;
-			if (((rs->raid_type->level != 1) &&
-			     (rebuild_cnt > rs->raid_type->parity_devs)) ||
-			    ((rs->raid_type->level == 1) &&
-			     (rebuild_cnt > (rs->md.raid_disks - 1)))) {
-				rs->ti->error = "Too many rebuild devices specified for given RAID type";
-				return -EINVAL;
-			}
-			if (value > rs->md.raid_disks) {
+			if (value >= rs->md.raid_disks) {
 				rs->ti->error = "Invalid rebuild index given";
 				return -EINVAL;
 			}
@@ -489,7 +642,8 @@ 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;
 			}
@@ -514,6 +668,14 @@ 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";
@@ -525,14 +687,42 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 		return -EINVAL;
 
 	if (rs->md.chunk_sectors)
-		rs->ti->split_io = rs->md.chunk_sectors;
+		max_io_len = rs->md.chunk_sectors;
 	else
-		rs->ti->split_io = region_size;
+		max_io_len = region_size;
 
-	if (rs->md.chunk_sectors)
-		rs->ti->split_io = rs->md.chunk_sectors;
-	else
-		rs->ti->split_io = region_size;
+	if (dm_set_target_max_io_len(rs->ti, max_io_len))
+		return -EINVAL;
+
+	if (rs->raid_type->level == 10) {
+		if (raid10_copies > rs->md.raid_disks) {
+			rs->ti->error = "Not enough devices to satisfy specification";
+			return -EINVAL;
+		}
+
+		/*
+		 * If the format is not "near", we only support
+		 * two copies at the moment.
+		 */
+		if (strcmp("near", raid10_format) && (raid10_copies > 2)) {
+			rs->ti->error = "Too many copies for given RAID10 format.";
+			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;
+	}
+	rs->md.dev_sectors = sectors_per_dev;
 
 	/* Assume there are no metadata devices until the drives are parsed */
 	rs->md.persistent = 0;
@@ -555,6 +745,9 @@ 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);
 }
 
@@ -604,7 +797,9 @@ static int read_disk_sb(struct md_rdev *rdev, int size)
 		return 0;
 
 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
-		DMERR("Failed to read device superblock");
+		DMERR("Failed to read superblock of device at position %d",
+		      rdev->raid_disk);
+		md_error(rdev->mddev, rdev);
 		return -EINVAL;
 	}
 
@@ -615,16 +810,18 @@ static int read_disk_sb(struct md_rdev *rdev, int size)
 
 static void super_sync(struct mddev *mddev, struct md_rdev *rdev)
 {
-	struct md_rdev *r, *t;
+	int i;
 	uint64_t failed_devices;
 	struct dm_raid_superblock *sb;
+	struct raid_set *rs = container_of(mddev, struct raid_set, md);
 
 	sb = page_address(rdev->sb_page);
 	failed_devices = le64_to_cpu(sb->failed_devices);
 
-	rdev_for_each(r, t, mddev)
-		if ((r->raid_disk >= 0) && test_bit(Faulty, &r->flags))
-			failed_devices |= (1ULL << r->raid_disk);
+	for (i = 0; i < mddev->raid_disks; i++)
+		if (!rs->dev[i].data_dev ||
+		    test_bit(Faulty, &(rs->dev[i].rdev.flags)))
+			failed_devices |= (1ULL << i);
 
 	memset(sb, 0, sizeof(*sb));
 
@@ -668,7 +865,14 @@ static int super_load(struct md_rdev *rdev, struct md_rdev *refdev)
 		return ret;
 
 	sb = page_address(rdev->sb_page);
-	if (sb->magic != cpu_to_le32(DM_RAID_MAGIC)) {
+
+	/*
+	 * Two cases that we want to write new superblocks and rebuild:
+	 * 1) New device (no matching magic number)
+	 * 2) Device specified for rebuild (!In_sync w/ offset == 0)
+	 */
+	if ((sb->magic != cpu_to_le32(DM_RAID_MAGIC)) ||
+	    (!test_bit(In_sync, &rdev->flags) && !rdev->recovery_offset)) {
 		super_sync(rdev->mddev, rdev);
 
 		set_bit(FirstUse, &rdev->flags);
@@ -700,7 +904,7 @@ static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 	struct dm_raid_superblock *sb;
 	uint32_t new_devs = 0;
 	uint32_t rebuilds = 0;
-	struct md_rdev *r, *t;
+	struct md_rdev *r;
 	struct dm_raid_superblock *sb2;
 
 	sb = page_address(rdev->sb_page);
@@ -715,17 +919,30 @@ static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 	/*
 	 * Reshaping is not currently allowed
 	 */
-	if ((le32_to_cpu(sb->level) != mddev->level) ||
-	    (le32_to_cpu(sb->layout) != mddev->layout) ||
-	    (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors)) {
-		DMERR("Reshaping arrays not yet supported.");
+	if (le32_to_cpu(sb->level) != mddev->level) {
+		DMERR("Reshaping arrays not yet supported. (RAID level change)");
+		return -EINVAL;
+	}
+	if (le32_to_cpu(sb->layout) != mddev->layout) {
+		DMERR("Reshaping arrays not yet supported. (RAID layout change)");
+		DMERR("  0x%X vs 0x%X", le32_to_cpu(sb->layout), mddev->layout);
+		DMERR("  Old layout: %s w/ %d copies",
+		      raid10_md_layout_to_format(le32_to_cpu(sb->layout)),
+		      raid10_md_layout_to_copies(le32_to_cpu(sb->layout)));
+		DMERR("  New layout: %s w/ %d copies",
+		      raid10_md_layout_to_format(mddev->layout),
+		      raid10_md_layout_to_copies(mddev->layout));
+		return -EINVAL;
+	}
+	if (le32_to_cpu(sb->stripe_sectors) != mddev->chunk_sectors) {
+		DMERR("Reshaping arrays not yet supported. (stripe sectors change)");
 		return -EINVAL;
 	}
 
 	/* We can only change the number of devices in RAID1 right now */
 	if ((rs->raid_type->level != 1) &&
 	    (le32_to_cpu(sb->num_devices) != mddev->raid_disks)) {
-		DMERR("Reshaping arrays not yet supported.");
+		DMERR("Reshaping arrays not yet supported. (device count change)");
 		return -EINVAL;
 	}
 
@@ -743,13 +960,10 @@ static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 	 *    case the In_sync bit will /not/ be set and
 	 *    recovery_cp must be MaxSector.
 	 */
-	rdev_for_each(r, t, mddev) {
+	rdev_for_each(r, mddev) {
 		if (!test_bit(In_sync, &r->flags)) {
-			if (!test_bit(FirstUse, &r->flags))
-				DMERR("Superblock area of "
-				      "rebuild device %d should have been "
-				      "cleared.", r->raid_disk);
-			set_bit(FirstUse, &r->flags);
+			DMINFO("Device %d specified for rebuild: "
+			       "Clearing superblock", r->raid_disk);
 			rebuilds++;
 		} else if (test_bit(FirstUse, &r->flags))
 			new_devs++;
@@ -778,7 +992,7 @@ static int super_init_validation(struct mddev *mddev, struct md_rdev *rdev)
 	 * Now we set the Faulty bit for those devices that are
 	 * recorded in the superblock as failed.
 	 */
-	rdev_for_each(r, t, mddev) {
+	rdev_for_each(r, mddev) {
 		if (!r->sb_page)
 			continue;
 		sb2 = page_address(r->sb_page);
@@ -851,11 +1065,25 @@ static int super_validate(struct mddev *mddev, struct md_rdev *rdev)
 static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 {
 	int ret;
-	struct md_rdev *rdev, *freshest, *tmp;
+	struct raid_dev *dev;
+	struct md_rdev *rdev, *tmp, *freshest;
 	struct mddev *mddev = &rs->md;
 
 	freshest = NULL;
-	rdev_for_each(rdev, tmp, mddev) {
+	rdev_for_each_safe(rdev, tmp, mddev) {
+		/*
+		 * Skipping super_load due to DMPF_SYNC will cause
+		 * the array to undergo initialization again as
+		 * though it were new.  This is the intended effect
+		 * of the "sync" directive.
+		 *
+		 * When reshaping capability is added, we must ensure
+		 * that the "sync" directive is disallowed during the
+		 * reshape.
+		 */
+		if (rs->print_flags & DMPF_SYNC)
+			continue;
+
 		if (!rdev->meta_bdev)
 			continue;
 
@@ -868,14 +1096,44 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 		case 0:
 			break;
 		default:
-			ti->error = "Failed to load superblock";
-			return ret;
+			dev = container_of(rdev, struct raid_dev, rdev);
+			if (dev->meta_dev)
+				dm_put_device(ti, dev->meta_dev);
+
+			dev->meta_dev = NULL;
+			rdev->meta_bdev = NULL;
+
+			if (rdev->sb_page)
+				put_page(rdev->sb_page);
+
+			rdev->sb_page = NULL;
+
+			rdev->sb_loaded = 0;
+
+			/*
+			 * We might be able to salvage the data device
+			 * even though the meta device has failed.  For
+			 * now, we behave as though '- -' had been
+			 * set for this device in the table.
+			 */
+			if (dev->data_dev)
+				dm_put_device(ti, dev->data_dev);
+
+			dev->data_dev = NULL;
+			rdev->bdev = NULL;
+
+			list_del(&rdev->same_set);
 		}
 	}
 
 	if (!freshest)
 		return 0;
 
+	if (validate_raid_redundancy(rs)) {
+		rs->ti->error = "Insufficient redundancy to activate array";
+		return -EINVAL;
+	}
+
 	/*
 	 * Validation of the freshest device provides the source of
 	 * validation for the remaining devices.
@@ -884,7 +1142,7 @@ static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
 	if (super_validate(mddev, freshest))
 		return -EINVAL;
 
-	rdev_for_each(rdev, tmp, mddev)
+	rdev_for_each(rdev, mddev)
 		if ((rdev != freshest) && super_validate(mddev, rdev))
 			return -EINVAL;
 
@@ -923,7 +1181,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	argv++;
 
 	/* number of RAID parameters */
-	if (strict_strtoul(argv[0], 10, &num_raid_params) < 0) {
+	if (kstrtoul(argv[0], 10, &num_raid_params) < 0) {
 		ti->error = "Cannot understand number of RAID parameters";
 		return -EINVAL;
 	}
@@ -936,7 +1194,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		return -EINVAL;
 	}
 
-	if ((strict_strtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
+	if ((kstrtoul(argv[num_raid_params], 10, &num_raid_devs) < 0) ||
 	    (num_raid_devs >= INT_MAX)) {
 		ti->error = "Cannot understand number of raid devices";
 		return -EINVAL;
@@ -971,6 +1229,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
 
 	INIT_WORK(&rs->md.event_work, do_table_event);
 	ti->private = rs;
+	ti->num_flush_bios = 1;
 
 	mutex_lock(&rs->md.reconfig_mutex);
 	ret = md_run(&rs->md);
@@ -982,12 +1241,19 @@ 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);
 
@@ -1003,7 +1269,7 @@ static void raid_dtr(struct dm_target *ti)
 	context_free(rs);
 }
 
-static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
+static int raid_map(struct dm_target *ti, struct bio *bio)
 {
 	struct raid_set *rs = ti->private;
 	struct mddev *mddev = &rs->md;
@@ -1013,8 +1279,33 @@ static int raid_map(struct dm_target *ti, struct bio *bio, union map_info *map_c
 	return DM_MAPIO_SUBMITTED;
 }
 
-static int raid_status(struct dm_target *ti, status_type_t type,
-		       char *result, unsigned maxlen)
+static const char *decipher_sync_action(struct mddev *mddev)
+{
+	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
+		return "frozen";
+
+	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
+		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+			return "reshape";
+
+		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
+				return "resync";
+			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
+				return "check";
+			return "repair";
+		}
+
+		if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
+			return "recover";
+	}
+
+	return "idle";
+}
+
+static void raid_status(struct dm_target *ti, status_type_t type,
+			unsigned status_flags, char *result, unsigned maxlen)
 {
 	struct raid_set *rs = ti->private;
 	unsigned raid_param_cnt = 1; /* at least 1 for chunksize */
@@ -1032,8 +1323,18 @@ static int raid_status(struct dm_target *ti, status_type_t type,
 			sync = rs->md.recovery_cp;
 
 		if (sync >= rs->md.resync_max_sectors) {
+			/*
+			 * Sync complete.
+			 */
 			array_in_sync = 1;
 			sync = rs->md.resync_max_sectors;
+		} else if (test_bit(MD_RECOVERY_REQUESTED, &rs->md.recovery)) {
+			/*
+			 * If "check" or "repair" is occurring, the array has
+			 * undergone and initial sync and the health characters
+			 * should not be 'a' anymore.
+			 */
+			array_in_sync = 1;
 		} else {
 			/*
 			 * The array may be doing an initial sync, or it may
@@ -1045,6 +1346,7 @@ static int raid_status(struct dm_target *ti, status_type_t type,
 				if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
 					array_in_sync = 1;
 		}
+
 		/*
 		 * Status characters:
 		 *  'D' = Dead/Failed device
@@ -1073,6 +1375,22 @@ static int raid_status(struct dm_target *ti, status_type_t type,
 		       (unsigned long long) sync,
 		       (unsigned long long) rs->md.resync_max_sectors);
 
+		/*
+		 * Sync action:
+		 *   See Documentation/device-mapper/dm-raid.c for
+		 *   information on each of these states.
+		 */
+		DMEMIT(" %s", decipher_sync_action(&rs->md));
+
+		/*
+		 * resync_mismatches/mismatch_cnt
+		 *   This field shows the number of discrepancies found when
+		 *   performing a "check" of the array.
+		 */
+		DMEMIT(" %llu",
+		       (strcmp(rs->md.last_sync_action, "check")) ? 0 :
+		       (unsigned long long)
+		       atomic64_read(&rs->md.resync_mismatches));
 		break;
 	case STATUSTYPE_TABLE:
 		/* The string you would use to construct this array */
@@ -1136,6 +1454,14 @@ 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 %s",
+			       raid10_md_layout_to_format(rs->md.layout));
+
 		DMEMIT(" %d", rs->md.raid_disks);
 		for (i = 0; i < rs->md.raid_disks; i++) {
 			if (rs->dev[i].meta_dev)
@@ -1149,11 +1475,64 @@ static int raid_status(struct dm_target *ti, status_type_t type,
 				DMEMIT(" -");
 		}
 	}
+}
+
+static int raid_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+	struct raid_set *rs = ti->private;
+	struct mddev *mddev = &rs->md;
+
+	if (!strcasecmp(argv[0], "reshape")) {
+		DMERR("Reshape not supported.");
+		return -EINVAL;
+	}
+
+	if (!mddev->pers || !mddev->pers->sync_request)
+		return -EINVAL;
+
+	if (!strcasecmp(argv[0], "frozen"))
+		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+	else
+		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+
+	if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
+		if (mddev->sync_thread) {
+			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+			md_reap_sync_thread(mddev);
+		}
+	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+		return -EBUSY;
+	else if (!strcasecmp(argv[0], "resync"))
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	else if (!strcasecmp(argv[0], "recover")) {
+		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	} else {
+		if (!strcasecmp(argv[0], "check"))
+			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
+		else if (!!strcasecmp(argv[0], "repair"))
+			return -EINVAL;
+		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
+		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
+	}
+	if (mddev->ro == 2) {
+		/* A write to sync_action is enough to justify
+		 * canceling read-auto mode
+		 */
+		mddev->ro = 0;
+		if (!mddev->suspended)
+			md_wakeup_thread(mddev->sync_thread);
+	}
+	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	if (!mddev->suspended)
+		md_wakeup_thread(mddev->thread);
 
 	return 0;
 }
 
-static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data)
+static int raid_iterate_devices(struct dm_target *ti,
+				iterate_devices_callout_fn fn, void *data)
 {
 	struct raid_set *rs = ti->private;
 	unsigned i;
@@ -1194,27 +1573,92 @@ static void raid_postsuspend(struct dm_target *ti)
 	mddev_suspend(&rs->md);
 }
 
+static void attempt_restore_of_faulty_devices(struct raid_set *rs)
+{
+	int i;
+	uint64_t failed_devices, cleared_failed_devices = 0;
+	unsigned long flags;
+	struct dm_raid_superblock *sb;
+	struct md_rdev *r;
+
+	for (i = 0; i < rs->md.raid_disks; i++) {
+		r = &rs->dev[i].rdev;
+		if (test_bit(Faulty, &r->flags) && r->sb_page &&
+		    sync_page_io(r, 0, r->sb_size, r->sb_page, READ, 1)) {
+			DMINFO("Faulty %s device #%d has readable super block."
+			       "  Attempting to revive it.",
+			       rs->raid_type->name, i);
+
+			/*
+			 * Faulty bit may be set, but sometimes the array can
+			 * be suspended before the personalities can respond
+			 * by removing the device from the array (i.e. calling
+			 * 'hot_remove_disk').  If they haven't yet removed
+			 * the failed device, its 'raid_disk' number will be
+			 * '>= 0' - meaning we must call this function
+			 * ourselves.
+			 */
+			if ((r->raid_disk >= 0) &&
+			    (r->mddev->pers->hot_remove_disk(r->mddev, r) != 0))
+				/* Failed to revive this device, try next */
+				continue;
+
+			r->raid_disk = i;
+			r->saved_raid_disk = i;
+			flags = r->flags;
+			clear_bit(Faulty, &r->flags);
+			clear_bit(WriteErrorSeen, &r->flags);
+			clear_bit(In_sync, &r->flags);
+			if (r->mddev->pers->hot_add_disk(r->mddev, r)) {
+				r->raid_disk = -1;
+				r->saved_raid_disk = -1;
+				r->flags = flags;
+			} else {
+				r->recovery_offset = 0;
+				cleared_failed_devices |= 1 << i;
+			}
+		}
+	}
+	if (cleared_failed_devices) {
+		rdev_for_each(r, &rs->md) {
+			sb = page_address(r->sb_page);
+			failed_devices = le64_to_cpu(sb->failed_devices);
+			failed_devices &= ~cleared_failed_devices;
+			sb->failed_devices = cpu_to_le64(failed_devices);
+		}
+	}
+}
+
 static void raid_resume(struct dm_target *ti)
 {
 	struct raid_set *rs = ti->private;
 
+	set_bit(MD_CHANGE_DEVS, &rs->md.flags);
 	if (!rs->bitmap_loaded) {
 		bitmap_load(&rs->md);
 		rs->bitmap_loaded = 1;
-	} else
-		md_wakeup_thread(rs->md.thread);
+	} else {
+		/*
+		 * A secondary resume while the device is active.
+		 * Take this opportunity to check whether any failed
+		 * devices are reachable again.
+		 */
+		attempt_restore_of_faulty_devices(rs);
+	}
 
+	clear_bit(MD_RECOVERY_FROZEN, &rs->md.recovery);
 	mddev_resume(&rs->md);
 }
 
 static struct target_type raid_target = {
 	.name = "raid",
-	.version = {1, 1, 0},
+	.version = {1, 5, 2},
 	.module = THIS_MODULE,
 	.ctr = raid_ctr,
 	.dtr = raid_dtr,
 	.map = raid_map,
 	.status = raid_status,
+	.message = raid_message,
 	.iterate_devices = raid_iterate_devices,
 	.io_hints = raid_io_hints,
 	.presuspend = raid_presuspend,
@@ -1224,6 +1668,10 @@ static struct target_type raid_target = {
 
 static int __init dm_raid_init(void)
 {
+	DMINFO("Loading target version %u.%u.%u",
+	       raid_target.version[0],
+	       raid_target.version[1],
+	       raid_target.version[2]);
 	return dm_register_target(&raid_target);
 }
 
@@ -1236,6 +1684,8 @@ 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");