9 files changed, 426 insertions, 219 deletions

diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt
index 946c73342cde..1c1844957166 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 f2f29c526544..982e3e390c45 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 +91,17 @@ 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";