[dm-devel] [PATCH 07/24] md/dm: create dm-raid456 module using md/raid5
NeilBrown
neilb at suse.de
Tue Jun 1 09:56:19 UTC 2010
Signed-off-by: NeilBrown <neilb at suse.de>
---
drivers/md/Kconfig | 8 +
drivers/md/Makefile | 1
drivers/md/dm-raid456.c | 437 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 446 insertions(+), 0 deletions(-)
create mode 100644 drivers/md/dm-raid456.c
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 4a6feac..3465363 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -256,6 +256,14 @@ config DM_MIRROR
Allow volume managers to mirror logical volumes, also
needed for live data migration tools such as 'pvmove'.
+config DM_RAID456
+ tristate "RAID 4/5/6 target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM && MD_RAID456 && EXPERIMENTAL
+ ---help---
+ A dm target that supports RAID4 RAID5 and RAID6 mapping
+
+ If unsure, say N.
+
config DM_LOG_USERSPACE
tristate "Mirror userspace logging (EXPERIMENTAL)"
depends on DM_MIRROR && EXPERIMENTAL && NET
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index e355e7f..0734fba 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o
obj-$(CONFIG_DM_LOG_USERSPACE) += dm-log-userspace.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
+obj-$(CONFIG_DM_RAID456) += dm-raid456.o
quiet_cmd_unroll = UNROLL $@
cmd_unroll = $(AWK) -f$(srctree)/$(src)/unroll.awk -vN=$(UNROLL) \
diff --git a/drivers/md/dm-raid456.c b/drivers/md/dm-raid456.c
new file mode 100644
index 0000000..5185a8f
--- /dev/null
+++ b/drivers/md/dm-raid456.c
@@ -0,0 +1,437 @@
+
+/*
+ * dm-raid456 - implemented as wrapper for md/raid456
+ *
+ */
+#include <linux/slab.h>
+#include "md.h"
+#include "raid5.h"
+#include "dm.h"
+
+struct raid_dev {
+ struct dm_dev *dev;
+ struct mdk_rdev_s rdev;
+};
+
+struct raid_set {
+ struct dm_target *ti;
+ struct mddev_s md;
+ struct raid_type *raid_type;
+ struct raid_dev dev[0];
+};
+
+/* Supported raid types and properties. */
+static struct raid_type {
+ const char *name; /* RAID algorithm. */
+ const char *descr; /* Descriptor text for logging. */
+ const unsigned parity_devs; /* # of parity devices. */
+ const unsigned minimal_devs; /* minimal # of devices in set. */
+ const unsigned level; /* RAID level. */
+ const unsigned algorithm; /* RAID algorithm. */
+} raid_types[] = {
+ {"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},
+ {"raid5_ls", "RAID5 (left symmetric)", 1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
+ {"raid5_rs", "RAID5 (right symmetric)", 1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
+ {"raid6_zr", "RAID6 (zero restart)", 2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART },
+ {"raid6_nr", "RAID6 (N restart)", 2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
+ {"raid6_nc", "RAID6 (N continue)", 2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
+};
+
+static struct raid_type *get_raid_type(char *name)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(raid_types); i++)
+ if (strcmp(raid_types[i].name, name) == 0)
+ return &raid_types[i];
+ return NULL;
+}
+
+static struct raid_set *
+context_alloc(struct raid_type *raid_type,
+ unsigned long chunk_size,
+ int recovery,
+ long raid_devs, sector_t sectors_per_dev,
+ struct dm_target *ti)
+{
+ struct raid_set *rs;
+
+ rs = kzalloc(sizeof(*rs) + raid_devs * sizeof(rs->dev[0]),
+ GFP_KERNEL);
+ if (!rs) {
+ ti->error = "Cannot allocate raid context";
+ return ERR_PTR(-ENOMEM);
+ }
+
+ mddev_init(&rs->md);
+
+ rs->ti = ti;
+ rs->raid_type = raid_type;
+ rs->md.raid_disks = raid_devs;
+ rs->md.level = raid_type->level;
+ rs->md.dev_sectors = sectors_per_dev;
+ rs->md.persistent = 0;
+ rs->md.external = 1;
+ rs->md.layout = raid_type->algorithm;
+ rs->md.chunk_sectors = chunk_size;
+ rs->md.recovery_cp = recovery ? 0 : MaxSector;
+
+ rs->md.new_level = rs->md.level;
+ rs->md.new_chunk_sectors = rs->md.chunk_sectors;
+ rs->md.new_layout = rs->md.layout;
+ rs->md.delta_disks = 0;
+
+ return rs;
+}
+
+static void context_free(struct raid_set *rs)
+{
+ int i;
+ for (i = 0; i < rs->md.raid_disks; i++)
+ if (rs->dev[i].dev)
+ dm_put_device(rs->ti, rs->dev[i].dev);
+ kfree(rs);
+}
+
+/* For every device we have two words
+ * device name, or "-" if missing
+ * offset from start of devices, in sectors
+ *
+ * This code parses those words.
+ */
+static int dev_parms(struct raid_set *rs, char **argv)
+{
+ int i;
+
+ for (i = 0; i < rs->md.raid_disks; i++, argv += 2) {
+ int err = 0;
+ unsigned long long offset;
+
+ md_rdev_init(&rs->dev[i].rdev);
+ rs->dev[i].rdev.raid_disk = i;
+
+ if (strcmp(argv[0], "-") == 0)
+ rs->dev[i].dev = NULL;
+ else
+ err = dm_get_device(rs->ti, argv[0],
+ dm_table_get_mode(rs->ti->table),
+ &rs->dev[i].dev);
+ if (err) {
+ rs->ti->error = "RAID device lookup failure";
+ return err;
+ }
+ if (strict_strtoull(argv[1], 10, &offset) < 0) {
+ rs->ti->error = "RAID device offset is bad";
+ return -EINVAL;
+ }
+ rs->dev[i].rdev.data_offset = offset;
+
+ set_bit(In_sync, &rs->dev[i].rdev.flags);
+
+ rs->dev[i].rdev.mddev = &rs->md;
+ if (rs->dev[i].dev) {
+ rs->dev[i].rdev.bdev = rs->dev[i].dev->bdev;
+ list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
+ }
+ }
+ return 0;
+}
+
+/*
+ * Construct a RAID4/5/6 mapping:
+ * Args:
+ * log_type #log_params <log_params> \
+ * raid_type #raid_params <raid_params> \
+ * rebuild-drive-A [rebuild-drive-B] \
+ * #raid_devs { <dev_path> <offset> }
+ * (a missing device is identified by dev_path == "-")
+ *
+ * log_type must be 'core'. We ignore region_size and use sync/nosync to
+ * decide if a resync is needed.
+ * raid_type is from "raid_types" above
+ * There are as many 'rebuild-drives' as 'parity_devs' in the raid_type.
+ * -1 means no drive needs rebuilding.
+ * raid_params are:
+ * chunk_size - in sectors, must be power of 2
+ */
+static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+ char *err = NULL;
+ int errnum = -EINVAL;
+ unsigned long cnt;
+ struct raid_type *rt;
+ unsigned long chunk_size;
+ int recovery = 1;
+ long raid_devs;
+ long rebuildA, rebuildB;
+ sector_t sectors_per_dev, chunks;
+ struct raid_set *rs = NULL;
+ int in_sync, i;
+
+ /* log type - core XXX [no]sync */
+ err = "Cannot parse log type";
+ if (argc < 2 ||
+ strcmp(argv[0], "core") != 0 ||
+ strict_strtoul(argv[1], 10, &cnt) < 0 ||
+ cnt + 2 > argc)
+ goto err;
+ if (cnt >= 2 && strcmp(argv[3], "sync") == 0)
+ recovery = 0;
+ argc -= cnt+2;
+ argv += cnt+2;
+
+ /* raid type */
+ err = "Cannot find raid_type";
+ if (argc < 1 ||
+ (rt = get_raid_type(argv[0])) == NULL)
+ goto err;
+ argc--; argv++;
+
+ /* number of parameters */
+ err = "Cannot understand number of RAID parameters";
+ if (argc < 1 ||
+ strict_strtoul(argv[0], 10, &cnt) < 0 ||
+ cnt + 1 > argc)
+ goto err;
+ argc--; argv++;
+
+ /* chunk size */
+ if (cnt) {
+ err = "Bad chunk size";
+ if (strict_strtoul(argv[0], 10, &chunk_size) < 0
+ || !is_power_of_2(chunk_size)
+ || chunk_size < 8
+ )
+ goto err;
+ cnt--; argc--; argv++;
+ }
+ /* Skip any extra args */
+ argc -= cnt;
+ argv += cnt;
+
+ /* drives needing rebuild */
+ err = "Cannot parse rebuild-drives";
+ if (argc < 1 ||
+ strict_strtol(argv[0], 10, &rebuildA) < 0)
+ goto err;
+ argc--; argv++;
+
+ rebuildB = -1;
+ if (rt->parity_devs == 2) {
+ if (argc < 1 ||
+ strict_strtol(argv[0], 10, &rebuildB) < 0)
+ goto err;
+ argc--; argv++;
+ }
+
+ /* number of raid devs */
+ err = "Bad number of raid devices";
+ if (argc < 1 ||
+ strict_strtol(argv[0], 10, &raid_devs) < 0 ||
+ raid_devs < rt->minimal_devs)
+ goto err;
+
+ err = "Bad number for rebuild device";
+ if (rebuildA < -1 || rebuildB < -1 ||
+ rebuildA >= raid_devs || rebuildB >= raid_devs)
+ goto err;
+
+ argc--; argv++;
+ err = "Wrong number of arguments for number of raid devices";
+ if (argc != raid_devs * 2)
+ goto err;
+
+ /* check the sizes all match */
+ sectors_per_dev = ti->len;
+ err = "Target length not divisible by number of data devices";
+ if (sector_div(sectors_per_dev, (raid_devs - rt->parity_devs)))
+ goto err;
+ chunks = sectors_per_dev;
+ err = "Device length not divisible by chunk_size";
+ if (sector_div(chunks, chunk_size))
+ goto err;
+
+
+ /* Now the devices: three words each */
+ rs = context_alloc(rt, chunk_size, recovery,
+ raid_devs, sectors_per_dev,
+ ti);
+ if (IS_ERR(rs))
+ return PTR_ERR(rs);
+
+ errnum = dev_parms(rs, argv);
+ if (errnum) {
+ err = ti->error;
+ goto err;
+ }
+ errnum = EINVAL;
+
+ err = "Rebuild device not present";
+ if (rebuildA >= 0) {
+ if (rs->dev[rebuildA].dev == NULL)
+ goto err;
+ clear_bit(In_sync, &rs->dev[rebuildA].rdev.flags);
+ rs->dev[rebuildA].rdev.recovery_offset = 0;
+ }
+ if (rebuildB >= 0) {
+ if (rs->dev[rebuildB].dev == NULL)
+ goto err;
+ clear_bit(In_sync, &rs->dev[rebuildB].rdev.flags);
+ rs->dev[rebuildB].rdev.recovery_offset = 0;
+ }
+ in_sync = 0;
+ for (i = 0; i < rs->md.raid_disks; i++)
+ if (rs->dev[i].dev &&
+ test_bit(In_sync, &rs->dev[i].rdev.flags))
+ in_sync++;
+ err = "Insufficient active RAID devices";
+ if (rs->md.raid_disks - in_sync > rt->parity_devs)
+ goto err;
+
+ ti->split_io = rs->md.chunk_sectors;
+ ti->private = rs;
+
+ mutex_lock(&rs->md.reconfig_mutex);
+ err = "Fail to run raid array";
+ errnum = md_run(&rs->md);
+ rs->md.in_sync = 0; /* Assume already marked dirty */
+ mutex_unlock(&rs->md.reconfig_mutex);
+
+ if (errnum)
+ goto err;
+ return 0;
+err:
+ if (rs)
+ context_free(rs);
+ ti->error = err;
+ return errnum;
+}
+
+static void raid_dtr(struct dm_target *ti)
+{
+ struct raid_set *rs = ti->private;
+
+ md_stop(&rs->md);
+ context_free(rs);
+}
+
+static int raid_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ struct raid_set *rs = ti->private;
+ mddev_t *mddev = &rs->md;
+
+ mddev->pers->make_request(mddev, bio);
+ return DM_MAPIO_SUBMITTED;
+}
+
+static int raid_status(struct dm_target *ti, status_type_t type,
+ char *result, unsigned maxlen)
+{
+ struct raid_set *rs = ti->private;
+ struct raid5_private_data *conf = rs->md.private;
+ int sz = 0;
+ int rbcnt;
+ int i;
+ sector_t sync;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ DMEMIT("%u ", rs->md.raid_disks);
+ for (i = 0; i < rs->md.raid_disks; i++) {
+ if (rs->dev[i].dev)
+ DMEMIT("%s ", rs->dev[i].dev->name);
+ else
+ DMEMIT("- ");
+ }
+ for (i = 0; i < rs->md.raid_disks; i++) {
+ if (test_bit(Faulty, &rs->dev[i].rdev.flags))
+ DMEMIT("D");
+ else if (test_bit(In_sync, &rs->dev[i].rdev.flags))
+ DMEMIT("A");
+ else
+ DMEMIT("Ai");
+ }
+ DMEMIT(" %u ", conf->max_nr_stripes);
+ if (test_bit(MD_RECOVERY_RUNNING, &rs->md.recovery))
+ sync = rs->md.curr_resync_completed;
+ else
+ sync = rs->md.recovery_cp;
+ if (sync > rs->md.resync_max_sectors)
+ sync = rs->md.resync_max_sectors;
+ DMEMIT("%llu/%llu ",
+ (unsigned long long) sync,
+ (unsigned long long) rs->md.resync_max_sectors);
+ DMEMIT("1 core");
+
+ break;
+ case STATUSTYPE_TABLE:
+ /* The string you would use to construct this array */
+ /* Pretend to use a core log with a region size of 1 sector */
+ DMEMIT("core 2 %u %ssync ", 1,
+ rs->md.recovery_cp == MaxSector ? "" : "no");
+ DMEMIT("%s ", rs->raid_type->name);
+ DMEMIT("1 %u ", rs->md.chunk_sectors);
+
+ /* Print 1 or 2 rebuild_dev numbers */
+ rbcnt = 0;
+ for (i = 0; i < rs->md.raid_disks; i++)
+ if (rs->dev[i].dev &&
+ !test_bit(In_sync, &rs->dev[i].rdev.flags) &&
+ rbcnt < rs->raid_type->parity_devs) {
+ DMEMIT("%u ", i);
+ rbcnt++;
+ }
+ while (rbcnt < rs->raid_type->parity_devs) {
+ DMEMIT("-1 ");
+ rbcnt++;
+ }
+
+ DMEMIT("%u ", rs->md.raid_disks);
+ for (i = 0; i < rs->md.raid_disks; i++) {
+ mdk_rdev_t *rdev = &rs->dev[i].rdev;
+
+ if (rs->dev[i].dev)
+ DMEMIT("%s ", rs->dev[i].dev->name);
+ else
+ DMEMIT("- ");
+
+ DMEMIT("%llu ", (unsigned long long)rdev->data_offset);
+ }
+ break;
+ }
+ return 0;
+}
+
+static struct target_type raid_target = {
+ .name = "raid45",
+ .version = {1, 0, 0},
+ .module = THIS_MODULE,
+ .ctr = raid_ctr,
+ .dtr = raid_dtr,
+ .map = raid_map,
+ .status = raid_status,
+};
+
+static int __init dm_raid_init(void)
+{
+ int r = dm_register_target(&raid_target);
+
+ return r;
+}
+
+static void __exit dm_raid_exit(void)
+{
+ dm_unregister_target(&raid_target);
+}
+
+module_init(dm_raid_init);
+module_exit(dm_raid_exit);
+
+MODULE_DESCRIPTION(DM_NAME " raid4/5/6 target");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("dm-raid4");
+MODULE_ALIAS("dm-raid5");
+MODULE_ALIAS("dm-raid6");
More information about the dm-devel
mailing list