1 files changed, 403 insertions, 16 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 88143a0303d2..69873806c50c 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -16,12 +16,10 @@
 #define DM_MSG_PREFIX "raid"
 
 /*
- * If the MD doesn't support MD_SYNC_STATE_FORCED yet, then
- * make it so the flag doesn't set anything.
+ * The following flags are used by dm-raid.c to set up the array state.
+ * They must be cleared before md_run is called.
  */
-#ifndef MD_SYNC_STATE_FORCED
-#define MD_SYNC_STATE_FORCED 0
-#endif
+#define FirstUse 10             /* rdev flag */
 
 struct raid_dev {
         /*
@@ -149,9 +147,16 @@ static void context_free(struct raid_set *rs)
 {
         int i;
 
-        for (i = 0; i < rs->md.raid_disks; i++)
+        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;
                 if (rs->dev[i].data_dev)
                         dm_put_device(rs->ti, rs->dev[i].data_dev);
+        }
 
         kfree(rs);
 }
@@ -161,7 +166,16 @@ static void context_free(struct raid_set *rs)
  *  <meta_dev>: meta device name or '-' if missing
  *  <data_dev>: data device name or '-' if missing
  *
- * This code parses those words.
+ * The following are permitted:
+ *    - -
+ *    - <data_dev>
+ *    <meta_dev> <data_dev>
+ *
+ * The following is not allowed:
+ *    <meta_dev> -
+ *
+ * This code parses those words.  If there is a failure,
+ * the caller must use context_free to unwind the operations.
  */
 static int dev_parms(struct raid_set *rs, char **argv)
 {
@@ -184,8 +198,16 @@ static int dev_parms(struct raid_set *rs, char **argv)
                 rs->dev[i].rdev.mddev = &rs->md;
 
                 if (strcmp(argv[0], "-")) {
-                        rs->ti->error = "Metadata devices not supported";
-                        return -EINVAL;
+                        ret = dm_get_device(rs->ti, argv[0],
+                                            dm_table_get_mode(rs->ti->table),
+                                            &rs->dev[i].meta_dev);
+                        rs->ti->error = "RAID metadata device lookup failure";
+                        if (ret)
+                                return ret;
+
+                        rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
+                        if (!rs->dev[i].rdev.sb_page)
+                                return -ENOMEM;
                 }
 
                 if (!strcmp(argv[1], "-")) {
@@ -195,6 +217,10 @@ static int dev_parms(struct raid_set *rs, char **argv)
                                 return -EINVAL;
                         }
 
+                        rs->ti->error = "No data device supplied with metadata device";
+                        if (rs->dev[i].meta_dev)
+                                return -EINVAL;
+
                         continue;
                 }
 
@@ -206,6 +232,10 @@ static int dev_parms(struct raid_set *rs, char **argv)
                         return ret;
                 }
 
+                if (rs->dev[i].meta_dev) {
+                        metadata_available = 1;
+                        rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
+                }
                 rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
                 list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
                 if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
@@ -334,22 +364,39 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
         num_raid_params--;
 
         /*
-         * Second, parse the unordered optional arguments
+         * We set each individual device as In_sync with a completed
+         * 'recovery_offset'.  If there has been a device failure or
+         * replacement then one of the following cases applies:
+         *
+         *   1) User specifies 'rebuild'.
+         *      - Device is reset when param is read.
+         *   2) A new device is supplied.
+         *      - No matching superblock found, resets device.
+         *   3) Device failure was transient and returns on reload.
+         *      - Failure noticed, resets device for bitmap replay.
+         *   4) Device hadn't completed recovery after previous failure.
+         *      - Superblock is read and overrides recovery_offset.
+         *
+         * What is found in the superblocks of the devices is always
+         * authoritative, unless 'rebuild' or '[no]sync' was specified.
          */
-        for (i = 0; i < rs->md.raid_disks; i++)
+        for (i = 0; i < rs->md.raid_disks; i++) {
                 set_bit(In_sync, &rs->dev[i].rdev.flags);
+                rs->dev[i].rdev.recovery_offset = MaxSector;
+        }
 
+        /*
+         * Second, parse the unordered optional arguments
+         */
         for (i = 0; i < num_raid_params; i++) {
                 if (!strcasecmp(argv[i], "nosync")) {
                         rs->md.recovery_cp = MaxSector;
                         rs->print_flags |= DMPF_NOSYNC;
-                        rs->md.flags |= MD_SYNC_STATE_FORCED;
                         continue;
                 }
                 if (!strcasecmp(argv[i], "sync")) {
                         rs->md.recovery_cp = 0;
                         rs->print_flags |= DMPF_SYNC;
-                        rs->md.flags |= MD_SYNC_STATE_FORCED;
                         continue;
                 }
 
@@ -482,13 +529,344 @@ static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
 }
 
 /*
+ * This structure is never routinely used by userspace, unlike md superblocks.
+ * Devices with this superblock should only ever be accessed via device-mapper.
+ */
+#define DM_RAID_MAGIC 0x64526D44
+struct dm_raid_superblock {
+        __le32 magic;           /* "DmRd" */
+        __le32 features;        /* Used to indicate possible future changes */
+
+        __le32 num_devices;     /* Number of devices in this array. (Max 64) */
+        __le32 array_position;  /* The position of this drive in the array */
+
+        __le64 events;          /* Incremented by md when superblock updated */
+        __le64 failed_devices;  /* Bit field of devices to indicate failures */
+
+        /*
+         * This offset tracks the progress of the repair or replacement of
+         * an individual drive.
+         */
+        __le64 disk_recovery_offset;
+
+        /*
+         * This offset tracks the progress of the initial array
+         * synchronisation/parity calculation.
+         */
+        __le64 array_resync_offset;
+
+        /*
+         * RAID characteristics
+         */
+        __le32 level;
+        __le32 layout;
+        __le32 stripe_sectors;
+
+        __u8 pad[452];          /* Round struct to 512 bytes. */
+                                /* Always set to 0 when writing. */
+} __packed;
+
+static int read_disk_sb(mdk_rdev_t *rdev, int size)
+{
+        BUG_ON(!rdev->sb_page);
+
+        if (rdev->sb_loaded)
+                return 0;
+
+        if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, 1)) {
+                DMERR("Failed to read device superblock");
+                return -EINVAL;
+        }
+
+        rdev->sb_loaded = 1;
+
+        return 0;
+}
+
+static void super_sync(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+        mdk_rdev_t *r, *t;
+        uint64_t failed_devices;
+        struct dm_raid_superblock *sb;
+
+        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);
+
+        memset(sb, 0, sizeof(*sb));
+
+        sb->magic = cpu_to_le32(DM_RAID_MAGIC);
+        sb->features = cpu_to_le32(0);  /* No features yet */
+
+        sb->num_devices = cpu_to_le32(mddev->raid_disks);
+        sb->array_position = cpu_to_le32(rdev->raid_disk);
+
+        sb->events = cpu_to_le64(mddev->events);
+        sb->failed_devices = cpu_to_le64(failed_devices);
+
+        sb->disk_recovery_offset = cpu_to_le64(rdev->recovery_offset);
+        sb->array_resync_offset = cpu_to_le64(mddev->recovery_cp);
+
+        sb->level = cpu_to_le32(mddev->level);
+        sb->layout = cpu_to_le32(mddev->layout);
+        sb->stripe_sectors = cpu_to_le32(mddev->chunk_sectors);
+}
+
+/*
+ * super_load
+ *
+ * This function creates a superblock if one is not found on the device
+ * and will decide which superblock to use if there's a choice.
+ *
+ * Return: 1 if use rdev, 0 if use refdev, -Exxx otherwise
+ */
+static int super_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev)
+{
+        int ret;
+        struct dm_raid_superblock *sb;
+        struct dm_raid_superblock *refsb;
+        uint64_t events_sb, events_refsb;
+
+        rdev->sb_start = 0;
+        rdev->sb_size = sizeof(*sb);
+
+        ret = read_disk_sb(rdev, rdev->sb_size);
+        if (ret)
+                return ret;
+
+        sb = page_address(rdev->sb_page);
+        if (sb->magic != cpu_to_le32(DM_RAID_MAGIC)) {
+                super_sync(rdev->mddev, rdev);
+
+                set_bit(FirstUse, &rdev->flags);
+
+                /* Force writing of superblocks to disk */
+                set_bit(MD_CHANGE_DEVS, &rdev->mddev->flags);
+
+                /* Any superblock is better than none, choose that if given */
+                return refdev ? 0 : 1;
+        }
+
+        if (!refdev)
+                return 1;
+
+        events_sb = le64_to_cpu(sb->events);
+
+        refsb = page_address(refdev->sb_page);
+        events_refsb = le64_to_cpu(refsb->events);
+
+        return (events_sb > events_refsb) ? 1 : 0;
+}
+
+static int super_init_validation(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+        int role;
+        struct raid_set *rs = container_of(mddev, struct raid_set, md);
+        uint64_t events_sb;
+        uint64_t failed_devices;
+        struct dm_raid_superblock *sb;
+        uint32_t new_devs = 0;
+        uint32_t rebuilds = 0;
+        mdk_rdev_t *r, *t;
+        struct dm_raid_superblock *sb2;
+
+        sb = page_address(rdev->sb_page);
+        events_sb = le64_to_cpu(sb->events);
+        failed_devices = le64_to_cpu(sb->failed_devices);
+
+        /*
+         * Initialise to 1 if this is a new superblock.
+         */
+        mddev->events = events_sb ? : 1;
+
+        /*
+         * 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.");
+                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.");
+                return -EINVAL;
+        }
+
+        if (!(rs->print_flags & (DMPF_SYNC | DMPF_NOSYNC)))
+                mddev->recovery_cp = le64_to_cpu(sb->array_resync_offset);
+
+        /*
+         * During load, we set FirstUse if a new superblock was written.
+         * There are two reasons we might not have a superblock:
+         * 1) The array is brand new - in which case, all of the
+         *    devices must have their In_sync bit set.  Also,
+         *    recovery_cp must be 0, unless forced.
+         * 2) This is a new device being added to an old array
+         *    and the new device needs to be rebuilt - in which
+         *    case the In_sync bit will /not/ be set and
+         *    recovery_cp must be MaxSector.
+         */
+        rdev_for_each(r, t, 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);
+                        rebuilds++;
+                } else if (test_bit(FirstUse, &r->flags))
+                        new_devs++;
+        }
+
+        if (!rebuilds) {
+                if (new_devs == mddev->raid_disks) {
+                        DMINFO("Superblocks created for new array");
+                        set_bit(MD_ARRAY_FIRST_USE, &mddev->flags);
+                } else if (new_devs) {
+                        DMERR("New device injected "
+                              "into existing array without 'rebuild' "
+                              "parameter specified");
+                        return -EINVAL;
+                }
+        } else if (new_devs) {
+                DMERR("'rebuild' devices cannot be "
+                      "injected into an array with other first-time devices");
+                return -EINVAL;
+        } else if (mddev->recovery_cp != MaxSector) {
+                DMERR("'rebuild' specified while array is not in-sync");
+                return -EINVAL;
+        }
+
+        /*
+         * Now we set the Faulty bit for those devices that are
+         * recorded in the superblock as failed.
+         */
+        rdev_for_each(r, t, mddev) {
+                if (!r->sb_page)
+                        continue;
+                sb2 = page_address(r->sb_page);
+                sb2->failed_devices = 0;
+
+                /*
+                 * Check for any device re-ordering.
+                 */
+                if (!test_bit(FirstUse, &r->flags) && (r->raid_disk >= 0)) {
+                        role = le32_to_cpu(sb2->array_position);
+                        if (role != r->raid_disk) {
+                                if (rs->raid_type->level != 1) {
+                                        rs->ti->error = "Cannot change device "
+                                                "positions in RAID array";
+                                        return -EINVAL;
+                                }
+                                DMINFO("RAID1 device #%d now at position #%d",
+                                       role, r->raid_disk);
+                        }
+
+                        /*
+                         * Partial recovery is performed on
+                         * returning failed devices.
+                         */
+                        if (failed_devices & (1 << role))
+                                set_bit(Faulty, &r->flags);
+                }
+        }
+
+        return 0;
+}
+
+static int super_validate(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+        struct dm_raid_superblock *sb = page_address(rdev->sb_page);
+
+        /*
+         * If mddev->events is not set, we know we have not yet initialized
+         * the array.
+         */
+        if (!mddev->events && super_init_validation(mddev, rdev))
+                return -EINVAL;
+
+        mddev->bitmap_info.offset = 4096 >> 9; /* Enable bitmap creation */
+        rdev->mddev->bitmap_info.default_offset = 4096 >> 9;
+        if (!test_bit(FirstUse, &rdev->flags)) {
+                rdev->recovery_offset = le64_to_cpu(sb->disk_recovery_offset);
+                if (rdev->recovery_offset != MaxSector)
+                        clear_bit(In_sync, &rdev->flags);
+        }
+
+        /*
+         * If a device comes back, set it as not In_sync and no longer faulty.
+         */
+        if (test_bit(Faulty, &rdev->flags)) {
+                clear_bit(Faulty, &rdev->flags);
+                clear_bit(In_sync, &rdev->flags);
+                rdev->saved_raid_disk = rdev->raid_disk;
+                rdev->recovery_offset = 0;
+        }
+
+        clear_bit(FirstUse, &rdev->flags);
+
+        return 0;
+}
+
+/*
+ * Analyse superblocks and select the freshest.
+ */
+static int analyse_superblocks(struct dm_target *ti, struct raid_set *rs)
+{
+        int ret;
+        mdk_rdev_t *rdev, *freshest, *tmp;
+        mddev_t *mddev = &rs->md;
+
+        freshest = NULL;
+        rdev_for_each(rdev, tmp, mddev) {
+                if (!rdev->meta_bdev)
+                        continue;
+
+                ret = super_load(rdev, freshest);
+
+                switch (ret) {
+                case 1:
+                        freshest = rdev;
+                        break;
+                case 0:
+                        break;
+                default:
+                        ti->error = "Failed to load superblock";
+                        return ret;
+                }
+        }
+
+        if (!freshest)
+                return 0;
+
+        /*
+         * Validation of the freshest device provides the source of
+         * validation for the remaining devices.
+         */
+        ti->error = "Unable to assemble array: Invalid superblocks";
+        if (super_validate(mddev, freshest))
+                return -EINVAL;
+
+        rdev_for_each(rdev, tmp, mddev)
+                if ((rdev != freshest) && super_validate(mddev, rdev))
+                        return -EINVAL;
+
+        return 0;
+}
+
+/*
  * Construct a RAID4/5/6 mapping:
  * Args:
  *      <raid_type> <#raid_params> <raid_params>                \
  *      <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
  *
- * ** metadata devices are not supported yet, use '-' instead **
- *
  * <raid_params> varies by <raid_type>.  See 'parse_raid_params' for
  * details on possible <raid_params>.
  */
@@ -556,6 +934,11 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
         if (ret)
                 goto bad;
 
+        rs->md.sync_super = super_sync;
+        ret = analyse_superblocks(ti, rs);
+        if (ret)
+                goto bad;
+
         INIT_WORK(&rs->md.event_work, do_table_event);
         ti->private = rs;
 
@@ -698,7 +1081,10 @@ static int raid_status(struct dm_target *ti, status_type_t type,
 
                 DMEMIT(" %d", rs->md.raid_disks);
                 for (i = 0; i < rs->md.raid_disks; i++) {
-                        DMEMIT(" -"); /* metadata device */
+                        if (rs->dev[i].meta_dev)
+                                DMEMIT(" %s", rs->dev[i].meta_dev->name);
+                        else
+                                DMEMIT(" -");
 
                         if (rs->dev[i].data_dev)
                                 DMEMIT(" %s", rs->dev[i].data_dev->name);
@@ -755,6 +1141,7 @@ static void raid_resume(struct dm_target *ti)
 {
         struct raid_set *rs = ti->private;
 
+        bitmap_load(&rs->md);
         mddev_resume(&rs->md);
 }