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Message-ID: <20071018191747.GB848@2ka.mipt.ru>
Date: Thu, 18 Oct 2007 23:17:47 +0400
From: Evgeniy Polyakov <johnpol@....mipt.ru>
To: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [1/3] Distributed storage. Core files.
Signed-off-by: Evgeniy Polyakov <johnpol@....mipt.ru>
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index dd88e33..fcf042d 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_VIODASD) += viodasd.o
obj-$(CONFIG_BLK_DEV_SX8) += sx8.o
obj-$(CONFIG_BLK_DEV_UB) += ub.o
+obj-$(CONFIG_DST) += dst/
diff --git a/drivers/block/dst/Kconfig b/drivers/block/dst/Kconfig
new file mode 100644
index 0000000..5bb9de8
--- /dev/null
+++ b/drivers/block/dst/Kconfig
@@ -0,0 +1,20 @@
+config DST
+ tristate "Distributed storage"
+ depends on NET
+ select CONNECTOR
+ ---help---
+ This driver allows to create a distributed storage.
+
+config DST_ALG_LINEAR
+ tristate "Linear distribution algorithm"
+ depends on DST
+ ---help---
+ This module allows to create linear mapping of the nodes
+ in the distributed storage.
+
+config DST_ALG_MIRROR
+ tristate "Mirror distribution algorithm"
+ depends on DST
+ ---help---
+ This module allows to create a mirror of the noes in the
+ distributed storage.
diff --git a/drivers/block/dst/Makefile b/drivers/block/dst/Makefile
new file mode 100644
index 0000000..1400e94
--- /dev/null
+++ b/drivers/block/dst/Makefile
@@ -0,0 +1,6 @@
+obj-$(CONFIG_DST) += dst.o
+
+dst-y := dcore.o kst.o
+
+obj-$(CONFIG_DST_ALG_LINEAR) += alg_linear.o
+obj-$(CONFIG_DST_ALG_MIRROR) += alg_mirror.o
diff --git a/drivers/block/dst/dcore.c b/drivers/block/dst/dcore.c
new file mode 100644
index 0000000..fdbfc7b
--- /dev/null
+++ b/drivers/block/dst/dcore.c
@@ -0,0 +1,1533 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@....mipt.ru>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/connector.h>
+#include <linux/socket.h>
+#include <linux/dst.h>
+#include <linux/device.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/buffer_head.h>
+
+#include <net/sock.h>
+
+static LIST_HEAD(dst_storage_list);
+static LIST_HEAD(dst_alg_list);
+static DEFINE_MUTEX(dst_storage_lock);
+static DEFINE_MUTEX(dst_alg_lock);
+static int dst_major;
+static struct kst_worker *kst_main_worker;
+static struct cb_id cn_dst_id = { CN_DST_IDX, CN_DST_VAL };
+
+struct kmem_cache *dst_request_cache;
+
+/*
+ * DST sysfs tree. For device called 'storage' which is formed
+ * on top of two nodes this looks like this:
+ *
+ * /sys/devices/storage/
+ * /sys/devices/storage/alg : alg_linear
+ * /sys/devices/storage/n-800/type : R: 192.168.4.80:1025
+ * /sys/devices/storage/n-800/size : 800
+ * /sys/devices/storage/n-800/start : 800
+ * /sys/devices/storage/n-0/type : R: 192.168.4.81:1025
+ * /sys/devices/storage/n-0/size : 800
+ * /sys/devices/storage/n-0/start : 0
+ * /sys/devices/storage/remove_all_nodes
+ * /sys/devices/storage/nodes : sectors (start [size]): 0 [800] | 800 [800]
+ * /sys/devices/storage/name : storage
+ */
+
+static int dst_dev_match(struct device *dev, struct device_driver *drv)
+{
+ return 1;
+}
+
+static void dst_dev_release(struct device *dev)
+{
+}
+
+static struct bus_type dst_dev_bus_type = {
+ .name = "dst",
+ .match = &dst_dev_match,
+};
+
+static struct device dst_dev = {
+ .bus = &dst_dev_bus_type,
+ .release = &dst_dev_release
+};
+
+static void dst_node_release(struct device *dev)
+{
+}
+
+static struct device dst_node_dev = {
+ .release = &dst_node_release
+};
+
+static struct bio_set *dst_bio_set;
+
+static void dst_destructor(struct bio *bio)
+{
+ bio_free(bio, dst_bio_set);
+}
+
+/*
+ * Internal callback for local requests (i.e. for local disk),
+ * which are splitted between nodes (part with local node destination
+ * ends up with this ->bi_end_io() callback).
+ */
+static int dst_end_io(struct bio *bio, unsigned int size, int err)
+{
+ struct bio *orig_bio = bio->bi_private;
+
+ if (bio->bi_size)
+ return 0;
+
+ dprintk("%s: bio: %p, orig_bio: %p, size: %u, orig_size: %u.\n",
+ __func__, bio, orig_bio, size, orig_bio->bi_size);
+
+ bio_endio(orig_bio, size, 0);
+ bio_put(bio);
+ return 0;
+}
+
+/*
+ * This function sends processing request down to block layer (for local node)
+ * or to network state machine (for remote node).
+ */
+static int dst_node_push(struct dst_request *req)
+{
+ int err = 0;
+ struct dst_node *n = req->node;
+
+ if (n->bdev) {
+ struct bio *bio = req->bio;
+
+ dprintk("%s: start: %llu, num: %d, idx: %d, offset: %u, "
+ "size: %llu, bi_idx: %d, bi_vcnt: %d.\n",
+ __func__, req->start, req->num, req->idx,
+ req->offset, req->size, bio->bi_idx, bio->bi_vcnt);
+
+ if (likely(bio->bi_idx == req->idx &&
+ bio->bi_vcnt == req->num)) {
+ bio->bi_bdev = n->bdev;
+ bio->bi_sector = req->start;
+ } else {
+ struct bio *clone = bio_alloc_bioset(GFP_NOIO,
+ bio->bi_max_vecs, dst_bio_set);
+ struct bio_vec *bv;
+
+ err = -ENOMEM;
+ if (!clone)
+ goto out_put;
+
+ __bio_clone(clone, bio);
+
+ bv = bio_iovec_idx(clone, req->idx);
+ bv->bv_offset += req->offset;
+ clone->bi_idx = req->idx;
+ clone->bi_vcnt = req->num;
+ clone->bi_bdev = n->bdev;
+ clone->bi_sector = req->start;
+ clone->bi_destructor = dst_destructor;
+ clone->bi_private = bio;
+ clone->bi_size = req->orig_size;
+ clone->bi_end_io = &dst_end_io;
+ req->bio = clone;
+
+ dprintk("%s: start: %llu, num: %d, idx: %d, "
+ "offset: %u, size: %llu, "
+ "bi_idx: %d, bi_vcnt: %d, req: %p, bio: %p.\n",
+ __func__, req->start, req->num, req->idx,
+ req->offset, req->size,
+ clone->bi_idx, clone->bi_vcnt, req, req->bio);
+
+ }
+ }
+
+ err = n->st->alg->ops->remap(req);
+
+out_put:
+ dst_node_put(n);
+ return err;
+}
+
+/*
+ * This function is invoked from block layer request processing function,
+ * its task is to remap block request to different nodes.
+ */
+static int dst_remap(struct dst_storage *st, struct bio *bio)
+{
+ struct dst_node *n;
+ int err = -EINVAL, i, cnt;
+ unsigned int bio_sectors = bio->bi_size>>9;
+ struct bio_vec *bv;
+ struct dst_request req;
+ u64 rest_in_node, start, total_size;
+
+ mutex_lock(&st->tree_lock);
+ n = dst_storage_tree_search(st, bio->bi_sector);
+ mutex_unlock(&st->tree_lock);
+
+ if (!n) {
+ dprintk("%s: failed to find a node for bio: %p, "
+ "sector: %llu.\n",
+ __func__, bio, bio->bi_sector);
+ return -ENODEV;
+ }
+
+ dprintk("%s: bio: %llu-%llu, dev: %llu-%llu, in sectors.\n",
+ __func__, bio->bi_sector, bio->bi_sector+bio_sectors,
+ n->start, n->start+n->size);
+
+ memset(&req, 0, sizeof(struct dst_request));
+
+ start = bio->bi_sector;
+ total_size = bio->bi_size;
+
+ req.flags = (test_bit(DST_NODE_FROZEN, &n->flags))?
+ DST_REQ_ALWAYS_QUEUE:0;
+ req.start = start - n->start;
+ req.offset = 0;
+ req.state = n->state;
+ req.node = n;
+ req.bio = bio;
+
+ req.size = bio->bi_size;
+ req.orig_size = bio->bi_size;
+ req.idx = bio->bi_idx;
+ req.num = bio->bi_vcnt;
+
+ req.bio_endio = &kst_bio_endio;
+
+ /*
+ * Common fast path - block request does not cross
+ * boundaries between nodes.
+ */
+ if (likely(bio->bi_sector + bio_sectors <= n->start + n->size))
+ return dst_node_push(&req);
+
+ req.size = 0;
+ req.idx = 0;
+ req.num = 1;
+
+ cnt = bio->bi_vcnt;
+
+ rest_in_node = to_bytes(n->size - req.start);
+
+ for (i = 0; i < cnt; ++i) {
+ bv = bio_iovec_idx(bio, i);
+
+ if (req.size + bv->bv_len >= rest_in_node) {
+ unsigned int diff = req.size + bv->bv_len -
+ rest_in_node;
+
+ req.size += bv->bv_len - diff;
+ req.start = start - n->start;
+ req.orig_size = req.size;
+ req.bio = bio;
+ req.bio_endio = &kst_bio_endio;
+
+ dprintk("%s: split: start: %llu/%llu, size: %llu, "
+ "total_size: %llu, diff: %u, idx: %d, "
+ "num: %d, bv_len: %u, bv_offset: %u.\n",
+ __func__, start, req.start, req.size,
+ total_size, diff, req.idx, req.num,
+ bv->bv_len, bv->bv_offset);
+
+ err = dst_node_push(&req);
+ if (err)
+ break;
+
+ total_size -= req.orig_size;
+
+ if (!total_size)
+ break;
+
+ start += to_sector(req.orig_size);
+
+ req.flags = (test_bit(DST_NODE_FROZEN, &n->flags))?
+ DST_REQ_ALWAYS_QUEUE:0;
+ req.orig_size = req.size = diff;
+
+ if (diff) {
+ req.offset = bv->bv_len - diff;
+ req.idx = req.num - 1;
+ } else {
+ req.idx = req.num;
+ req.offset = 0;
+ }
+
+ dprintk("%s: next: start: %llu, size: %llu, "
+ "total_size: %llu, diff: %u, idx: %d, "
+ "num: %d, offset: %u, bv_len: %u, "
+ "bv_offset: %u.\n",
+ __func__, start, req.size, total_size, diff,
+ req.idx, req.num, req.offset,
+ bv->bv_len, bv->bv_offset);
+
+ mutex_lock(&st->tree_lock);
+ n = dst_storage_tree_search(st, start);
+ mutex_unlock(&st->tree_lock);
+
+ if (!n) {
+ err = -ENODEV;
+ dprintk("%s: failed to find a split node for "
+ "bio: %p, sector: %llu, start: %llu.\n",
+ __func__, bio, bio->bi_sector,
+ req.start);
+ break;
+ }
+
+ req.state = n->state;
+ req.node = n;
+ req.start = start - n->start;
+ rest_in_node = to_bytes(n->size - req.start);
+
+ dprintk("%s: req.start: %llu, start: %llu, "
+ "dev_start: %llu, dev_size: %llu, "
+ "rest_in_node: %llu.\n",
+ __func__, req.start, start, n->start,
+ n->size, rest_in_node);
+ } else {
+ req.size += bv->bv_len;
+ req.num++;
+ }
+ }
+
+ dprintk("%s: last request: start: %llu, size: %llu, "
+ "total_size: %llu.\n", __func__,
+ req.start, req.size, total_size);
+ if (total_size) {
+ req.orig_size = req.size;
+ req.bio = bio;
+ req.bio_endio = &kst_bio_endio;
+
+ dprintk("%s: last: start: %llu/%llu, size: %llu, "
+ "total_size: %llu, idx: %d, num: %d.\n",
+ __func__, start, req.start, req.size,
+ total_size, req.idx, req.num);
+
+ err = dst_node_push(&req);
+ if (!err) {
+ total_size -= req.orig_size;
+
+ BUG_ON(total_size != 0);
+ }
+ }
+
+ dprintk("%s: end bio: %p, err: %d.\n", __func__, bio, err);
+ return err;
+}
+
+
+/*
+ * Distributed storage erquest processing function.
+ * It calls algorithm spcific remapping code only.
+ */
+static int dst_request(request_queue_t *q, struct bio *bio)
+{
+ struct dst_storage *st = q->queuedata;
+ int err;
+
+ dprintk("\n%s: start: st: %p, bio: %p, cnt: %u.\n",
+ __func__, st, bio, bio->bi_vcnt);
+
+ err = dst_remap(st, bio);
+
+ dprintk("%s: end: st: %p, bio: %p, err: %d.\n",
+ __func__, st, bio, err);
+ return 0;
+}
+
+static void dst_unplug(request_queue_t *q)
+{
+}
+
+static int dst_flush(request_queue_t *q, struct gendisk *disk, sector_t *sec)
+{
+ return 0;
+}
+
+static struct block_device_operations dst_blk_ops = {
+ .owner = THIS_MODULE,
+};
+
+/*
+ * Block layer binding - disk is created when array is fully configured
+ * by userspace request.
+ */
+static int dst_create_disk(struct dst_storage *st)
+{
+ int err = -ENOMEM;
+
+ st->queue = blk_alloc_queue(GFP_KERNEL);
+ if (!st->queue)
+ goto err_out_exit;
+
+ st->queue->queuedata = st;
+ blk_queue_make_request(st->queue, dst_request);
+ blk_queue_bounce_limit(st->queue, BLK_BOUNCE_ANY);
+ st->queue->unplug_fn = dst_unplug;
+ st->queue->issue_flush_fn = dst_flush;
+
+ err = -EINVAL;
+ st->disk = alloc_disk(1);
+ if (!st->disk)
+ goto err_out_free_queue;
+
+ st->disk->major = dst_major;
+ st->disk->first_minor = (((unsigned long)st->disk) ^
+ (((unsigned long)st->disk) >> 31)) & 0xff;
+ st->disk->fops = &dst_blk_ops;
+ st->disk->queue = st->queue;
+ st->disk->private_data = st;
+ snprintf(st->disk->disk_name, sizeof(st->disk->disk_name),
+ "dst-%s-%d", st->name, st->disk->first_minor);
+
+ return 0;
+
+err_out_free_queue:
+ blk_cleanup_queue(st->queue);
+err_out_exit:
+ return err;
+}
+
+static void dst_remove_disk(struct dst_storage *st)
+{
+ del_gendisk(st->disk);
+ put_disk(st->disk);
+ blk_cleanup_queue(st->queue);
+}
+
+/*
+ * Shows node name in sysfs.
+ */
+static ssize_t dst_name_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_storage *st = container_of(dev, struct dst_storage, device);
+
+ return sprintf(buf, "%s\n", st->name);
+}
+
+static void dst_remove_all_nodes(struct dst_storage *st)
+{
+ struct dst_node *n, *node, *tmp;
+ struct rb_node *rb_node;
+
+ mutex_lock(&st->tree_lock);
+ while ((rb_node = rb_first(&st->tree_root)) != NULL) {
+ n = rb_entry(rb_node, struct dst_node, tree_node);
+ dprintk("%s: n: %p, start: %llu, size: %llu.\n",
+ __func__, n, n->start, n->size);
+ rb_erase(&n->tree_node, &st->tree_root);
+ if (!n->shared_head && atomic_read(&n->shared_num)) {
+ list_for_each_entry_safe(node, tmp, &n->shared, shared) {
+ list_del(&node->shared);
+ atomic_dec(&node->shared_head->refcnt);
+ node->shared_head = NULL;
+ dst_node_put(node);
+ }
+ }
+ dst_node_put(n);
+ }
+ mutex_unlock(&st->tree_lock);
+}
+
+/*
+ * Shows node layout in syfs.
+ */
+static ssize_t dst_nodes_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_storage *st = container_of(dev, struct dst_storage, device);
+ int size = PAGE_CACHE_SIZE, sz;
+ struct dst_node *n;
+ struct rb_node *rb_node;
+
+ sz = sprintf(buf, "sectors (start [size]): ");
+ size -= sz;
+ buf += sz;
+
+ mutex_lock(&st->tree_lock);
+ for (rb_node = rb_first(&st->tree_root); rb_node;
+ rb_node = rb_next(rb_node)) {
+ n = rb_entry(rb_node, struct dst_node, tree_node);
+ if (size < 32)
+ break;
+ sz = sprintf(buf, "%llu [%llu]", n->start, n->size);
+ buf += sz;
+ size -= sz;
+
+ if (!rb_next(rb_node))
+ break;
+
+ sz = sprintf(buf, " | ");
+ buf += sz;
+ size -= sz;
+ }
+ mutex_unlock(&st->tree_lock);
+ size -= sprintf(buf, "\n");
+ return PAGE_CACHE_SIZE - size;
+}
+
+/*
+ * Algorithm currently being used by given storage.
+ */
+static ssize_t dst_alg_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_storage *st = container_of(dev, struct dst_storage, device);
+ return sprintf(buf, "%s\n", st->alg->name);
+}
+
+/*
+ * Writing to this sysfs file allows to remove all nodes
+ * and storage itself automatically.
+ */
+static ssize_t dst_remove_nodes(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dst_storage *st = container_of(dev, struct dst_storage, device);
+ dst_remove_all_nodes(st);
+ return count;
+}
+
+static DEVICE_ATTR(name, 0444, dst_name_show, NULL);
+static DEVICE_ATTR(nodes, 0444, dst_nodes_show, NULL);
+static DEVICE_ATTR(alg, 0444, dst_alg_show, NULL);
+static DEVICE_ATTR(remove_all_nodes, 0644, NULL, dst_remove_nodes);
+
+static int dst_create_storage_attributes(struct dst_storage *st)
+{
+ int err;
+
+ err = device_create_file(&st->device, &dev_attr_name);
+ err = device_create_file(&st->device, &dev_attr_nodes);
+ err = device_create_file(&st->device, &dev_attr_alg);
+ err = device_create_file(&st->device, &dev_attr_remove_all_nodes);
+ return 0;
+}
+
+static void dst_remove_storage_attributes(struct dst_storage *st)
+{
+ device_remove_file(&st->device, &dev_attr_name);
+ device_remove_file(&st->device, &dev_attr_nodes);
+ device_remove_file(&st->device, &dev_attr_alg);
+ device_remove_file(&st->device, &dev_attr_remove_all_nodes);
+}
+
+static void dst_storage_sysfs_exit(struct dst_storage *st)
+{
+ dst_remove_storage_attributes(st);
+ device_unregister(&st->device);
+}
+
+static int dst_storage_sysfs_init(struct dst_storage *st)
+{
+ int err;
+
+ memcpy(&st->device, &dst_dev, sizeof(struct device));
+ snprintf(st->device.bus_id, sizeof(st->device.bus_id), "%s", st->name);
+
+ err = device_register(&st->device);
+ if (err) {
+ dprintk(KERN_ERR "Failed to register dst device %s, err: %d.\n",
+ st->name, err);
+ goto err_out_exit;
+ }
+
+ dst_create_storage_attributes(st);
+
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+/*
+ * This functions shows size and start of the appropriate node.
+ * Both are in sectors.
+ */
+static ssize_t dst_show_start(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_node *n = container_of(dev, struct dst_node, device);
+
+ return sprintf(buf, "%llu\n", n->start);
+}
+
+static ssize_t dst_show_size(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_node *n = container_of(dev, struct dst_node, device);
+
+ return sprintf(buf, "%llu\n", n->size);
+}
+
+/*
+ * Shows type of the remote node - device major/minor number
+ * for local nodes and address (af_inet ipv4/ipv6 only) for remote nodes.
+ */
+static ssize_t dst_show_type(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_node *n = container_of(dev, struct dst_node, device);
+ struct sockaddr addr;
+ struct socket *sock;
+ int addrlen;
+
+ if (!n->state && !n->bdev)
+ return 0;
+
+ if (n->bdev)
+ return sprintf(buf, "L: %d:%d\n",
+ MAJOR(n->bdev->bd_dev), MINOR(n->bdev->bd_dev));
+
+ sock = n->state->socket;
+ if (sock->ops->getname(sock, &addr, &addrlen, 2))
+ return 0;
+
+ if (sock->ops->family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
+ return sprintf(buf, "R: %u.%u.%u.%u:%d\n",
+ NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port));
+ } else if (sock->ops->family == AF_INET6) {
+ struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&addr;
+ return sprintf(buf,
+ "R: %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x:%d\n",
+ NIP6(sin->sin6_addr), ntohs(sin->sin6_port));
+ }
+ return 0;
+}
+
+static DEVICE_ATTR(start, 0444, dst_show_start, NULL);
+static DEVICE_ATTR(size, 0444, dst_show_size, NULL);
+static DEVICE_ATTR(type, 0444, dst_show_type, NULL);
+
+static int dst_create_node_attributes(struct dst_node *n)
+{
+ int err;
+
+ err = device_create_file(&n->device, &dev_attr_start);
+ err = device_create_file(&n->device, &dev_attr_size);
+ err = device_create_file(&n->device, &dev_attr_type);
+ return 0;
+}
+
+static void dst_remove_node_attributes(struct dst_node *n)
+{
+ device_remove_file(&n->device, &dev_attr_start);
+ device_remove_file(&n->device, &dev_attr_size);
+ device_remove_file(&n->device, &dev_attr_type);
+}
+
+static void dst_node_sysfs_exit(struct dst_node *n)
+{
+ if (n->device.parent == &n->st->device) {
+ dst_remove_node_attributes(n);
+ device_unregister(&n->device);
+ n->device.parent = NULL;
+ }
+}
+
+static int dst_node_sysfs_init(struct dst_node *n)
+{
+ int err;
+
+ memcpy(&n->device, &dst_node_dev, sizeof(struct device));
+
+ n->device.parent = &n->st->device;
+
+ snprintf(n->device.bus_id, sizeof(n->device.bus_id),
+ "n-%llu-%p", n->start, n);
+ err = device_register(&n->device);
+ if (err) {
+ dprintk(KERN_ERR "Failed to register node, err: %d.\n", err);
+ goto err_out_exit;
+ }
+
+ dst_create_node_attributes(n);
+
+ return 0;
+
+err_out_exit:
+ n->device.parent = NULL;
+ return err;
+}
+
+/*
+ * Gets a reference for given storage, if
+ * storage with given name and algorithm being used
+ * does not exist it is created.
+ */
+static struct dst_storage *dst_get_storage(char *name, char *aname, int alloc)
+{
+ struct dst_storage *st, *rst = NULL;
+ int err;
+ struct dst_alg *alg;
+
+ mutex_lock(&dst_storage_lock);
+ list_for_each_entry(st, &dst_storage_list, entry) {
+ if (!strcmp(name, st->name) && !strcmp(st->alg->name, aname)) {
+ rst = st;
+ atomic_inc(&st->refcnt);
+ break;
+ }
+ }
+ mutex_unlock(&dst_storage_lock);
+
+ if (rst || !alloc)
+ return rst;
+
+ st = kzalloc(sizeof(struct dst_storage), GFP_KERNEL);
+ if (!st)
+ return NULL;
+
+ mutex_init(&st->tree_lock);
+ /*
+ * One for storage itself,
+ * another one for attached node below.
+ */
+ atomic_set(&st->refcnt, 2);
+ snprintf(st->name, DST_NAMELEN, "%s", name);
+ st->tree_root.rb_node = NULL;
+
+ err = dst_storage_sysfs_init(st);
+ if (err)
+ goto err_out_free;
+
+ err = dst_create_disk(st);
+ if (err)
+ goto err_out_sysfs_exit;
+
+ mutex_lock(&dst_alg_lock);
+ list_for_each_entry(alg, &dst_alg_list, entry) {
+ if (!strcmp(alg->name, aname)) {
+ atomic_inc(&alg->refcnt);
+ try_module_get(alg->ops->owner);
+ st->alg = alg;
+ break;
+ }
+ }
+ mutex_unlock(&dst_alg_lock);
+
+ if (!st->alg)
+ goto err_out_disk_remove;
+
+ mutex_lock(&dst_storage_lock);
+ list_add_tail(&st->entry, &dst_storage_list);
+ mutex_unlock(&dst_storage_lock);
+
+ return st;
+
+err_out_disk_remove:
+ dst_remove_disk(st);
+err_out_sysfs_exit:
+ dst_storage_sysfs_init(st);
+err_out_free:
+ kfree(st);
+ return NULL;
+}
+
+/*
+ * Allows to allocate and add new algorithm by external modules.
+ */
+struct dst_alg *dst_alloc_alg(char *name, struct dst_alg_ops *ops)
+{
+ struct dst_alg *alg;
+
+ alg = kzalloc(sizeof(struct dst_alg), GFP_KERNEL);
+ if (!alg)
+ return NULL;
+ snprintf(alg->name, DST_NAMELEN, "%s", name);
+ atomic_set(&alg->refcnt, 1);
+ alg->ops = ops;
+
+ mutex_lock(&dst_alg_lock);
+ list_add_tail(&alg->entry, &dst_alg_list);
+ mutex_unlock(&dst_alg_lock);
+
+ return alg;
+}
+EXPORT_SYMBOL_GPL(dst_alloc_alg);
+
+static void dst_free_alg(struct dst_alg *alg)
+{
+ dprintk("%s: alg: %p.\n", __func__, alg);
+ kfree(alg);
+}
+
+/*
+ * Algorithm is never freed directly,
+ * since its module reference counter is increased
+ * by storage when it is created - just like network protocols.
+ */
+static inline void dst_put_alg(struct dst_alg *alg)
+{
+ dprintk("%s: alg: %p, refcnt: %d.\n",
+ __func__, alg, atomic_read(&alg->refcnt));
+ module_put(alg->ops->owner);
+ if (atomic_dec_and_test(&alg->refcnt))
+ dst_free_alg(alg);
+}
+
+/*
+ * Removing algorithm from main list of supported algorithms.
+ */
+void dst_remove_alg(struct dst_alg *alg)
+{
+ mutex_lock(&dst_alg_lock);
+ list_del_init(&alg->entry);
+ mutex_unlock(&dst_alg_lock);
+
+ dst_put_alg(alg);
+}
+EXPORT_SYMBOL_GPL(dst_remove_alg);
+
+static void dst_cleanup_node(struct dst_node *n)
+{
+ struct dst_storage *st = n->st;
+
+ dprintk("%s: node: %p.\n", __func__, n);
+
+ n->st->alg->ops->del_node(n);
+
+ if (n->shared_head) {
+ mutex_lock(&st->tree_lock);
+ list_del(&n->shared);
+ mutex_unlock(&st->tree_lock);
+
+ atomic_dec(&n->shared_head->refcnt);
+ dst_node_put(n->shared_head);
+ n->shared_head = NULL;
+ }
+
+ if (n->cleanup)
+ n->cleanup(n);
+ dst_node_sysfs_exit(n);
+ kfree(n);
+}
+
+static void dst_free_storage(struct dst_storage *st)
+{
+ dprintk("%s: st: %p.\n", __func__, st);
+
+ BUG_ON(rb_first(&st->tree_root) != NULL);
+
+ dst_put_alg(st->alg);
+ kfree(st);
+}
+
+static inline void dst_put_storage(struct dst_storage *st)
+{
+ dprintk("%s: st: %p, refcnt: %d.\n",
+ __func__, st, atomic_read(&st->refcnt));
+ if (atomic_dec_and_test(&st->refcnt))
+ dst_free_storage(st);
+}
+
+/*
+ * This can deadlock if called under st->tree_lock being held,
+ * so take care to only call this when reference counter can not
+ * hit zero and thus start node freeing.
+ */
+void dst_node_put(struct dst_node *n)
+{
+ dprintk("%s: node: %p, start: %llu, size: %llu, refcnt: %d.\n",
+ __func__, n, n->start, n->size,
+ atomic_read(&n->refcnt));
+
+ if (atomic_dec_and_test(&n->refcnt)) {
+ struct dst_storage *st = n->st;
+
+ dprintk("%s: freeing node: %p, start: %llu, size: %llu, "
+ "refcnt: %d.\n",
+ __func__, n, n->start, n->size,
+ atomic_read(&n->refcnt));
+
+ dst_cleanup_node(n);
+ dst_put_storage(st);
+ }
+}
+EXPORT_SYMBOL_GPL(dst_node_put);
+
+static inline int dst_compare_id(struct dst_node *old, u64 new)
+{
+ if (old->start + old->size <= new)
+ return 1;
+ if (old->start > new)
+ return -1;
+ return 0;
+}
+
+/*
+ * Tree of of the nodes, which form the storage.
+ * Tree is indexed via start of the node and its size.
+ * Comparison function above.
+ */
+struct dst_node *dst_storage_tree_search(struct dst_storage *st, u64 start)
+{
+ struct rb_node *n = st->tree_root.rb_node;
+ struct dst_node *dn;
+ int cmp;
+
+ while (n) {
+ dn = rb_entry(n, struct dst_node, tree_node);
+
+ cmp = dst_compare_id(dn, start);
+ dprintk("%s: tree: %llu-%llu, new: %llu.\n",
+ __func__, dn->start, dn->start+dn->size, start);
+ if (cmp < 0)
+ n = n->rb_left;
+ else if (cmp > 0)
+ n = n->rb_right;
+ else {
+ return dst_node_get(dn);
+ }
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(dst_storage_tree_search);
+
+/*
+ * This function allows to remove a node with given start address
+ * from the storage.
+ */
+static struct dst_node *dst_storage_tree_del(struct dst_storage *st, u64 start)
+{
+ struct dst_node *n = dst_storage_tree_search(st, start);
+
+ if (!n)
+ return NULL;
+
+ rb_erase(&n->tree_node, &st->tree_root);
+ dst_node_put(n);
+ return n;
+}
+
+/*
+ * This function allows to add given node to the storage.
+ * Returns -EEXIST if the same area is already covered by another node.
+ * This is return must be checked for redundancy algorithms.
+ */
+static struct dst_node *dst_storage_tree_add(struct dst_node *new,
+ struct dst_storage *st)
+{
+ struct rb_node **n = &st->tree_root.rb_node, *parent = NULL;
+ struct dst_node *dn;
+ int cmp;
+
+ while (*n) {
+ parent = *n;
+ dn = rb_entry(parent, struct dst_node, tree_node);
+
+ cmp = dst_compare_id(dn, new->start);
+ dprintk("%s: tree: %llu-%llu, new: %llu.\n",
+ __func__, dn->start, dn->start+dn->size,
+ new->start);
+ if (cmp < 0)
+ n = &parent->rb_left;
+ else if (cmp > 0)
+ n = &parent->rb_right;
+ else {
+ return dn;
+ }
+ }
+
+ rb_link_node(&new->tree_node, parent, n);
+ rb_insert_color(&new->tree_node, &st->tree_root);
+
+ return NULL;
+}
+
+/*
+ * This function finds devices major/minor numbers for given pathname.
+ */
+static int dst_lookup_device(const char *path, dev_t *dev)
+{
+ int err;
+ struct nameidata nd;
+ struct inode *inode;
+
+ err = path_lookup(path, LOOKUP_FOLLOW, &nd);
+ if (err)
+ return err;
+
+ inode = nd.dentry->d_inode;
+ if (!inode) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ if (!S_ISBLK(inode->i_mode)) {
+ err = -ENOTBLK;
+ goto out;
+ }
+
+ *dev = inode->i_rdev;
+
+out:
+ path_release(&nd);
+ return err;
+}
+
+/*
+ * Cleanup routings for local, local exporting and remote nodes.
+ */
+static void dst_cleanup_remote(struct dst_node *n)
+{
+ if (n->state) {
+ kst_state_exit(n->state);
+ n->state = NULL;
+ }
+}
+
+static void dst_cleanup_local(struct dst_node *n)
+{
+ if (n->bdev) {
+ sync_blockdev(n->bdev);
+ blkdev_put(n->bdev);
+ n->bdev = NULL;
+ }
+}
+
+static void dst_cleanup_local_export(struct dst_node *n)
+{
+ dst_cleanup_local(n);
+ dst_cleanup_remote(n);
+}
+
+/*
+ * Setup routings for local, local exporting and remote nodes.
+ */
+static int dst_setup_local(struct dst_node *n, struct dst_ctl *ctl,
+ struct dst_local_ctl *l)
+{
+ dev_t dev;
+ int err;
+
+ err = dst_lookup_device(l->name, &dev);
+ if (err)
+ return err;
+
+ n->bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+ if (!n->bdev)
+ return -ENODEV;
+
+ if (!n->size)
+ n->size = get_capacity(n->bdev->bd_disk);
+
+ return 0;
+}
+
+static int dst_setup_local_export(struct dst_node *n, struct dst_ctl *ctl,
+ struct dst_le_template *tmp)
+{
+ int err;
+
+ err = dst_setup_local(n, ctl, &tmp->le->lctl);
+ if (err)
+ goto err_out_exit;
+
+ n->state = kst_listener_state_init(n, tmp);
+ if (IS_ERR(n->state)) {
+ err = PTR_ERR(n->state);
+ goto err_out_cleanup;
+ }
+
+ return 0;
+
+err_out_cleanup:
+ dst_cleanup_local(n);
+err_out_exit:
+ return err;
+}
+
+static int dst_request_remote_config(struct dst_node *n, struct socket *sock)
+{
+ struct dst_remote_request cfg;
+ struct msghdr msg;
+ struct kvec iov;
+ int err;
+
+ memset(&cfg, 0, sizeof(struct dst_remote_request));
+ cfg.cmd = cpu_to_be32(DST_REMOTE_CFG);
+
+ iov.iov_base = &cfg;
+ iov.iov_len = sizeof(struct dst_remote_request);
+
+ msg.msg_iov = (struct iovec *)&iov;
+ msg.msg_iovlen = 1;
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = MSG_WAITALL;
+
+ err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
+ if (err <= 0) {
+ if (err == 0)
+ err = -ECONNRESET;
+ return err;
+ }
+
+ iov.iov_base = &cfg;
+ iov.iov_len = sizeof(struct dst_remote_request);
+
+ msg.msg_iov = (struct iovec *)&iov;
+ msg.msg_iovlen = 1;
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = MSG_WAITALL;
+
+ err = kernel_recvmsg(sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags);
+ if (err <= 0) {
+ if (err == 0)
+ err = -ECONNRESET;
+ return err;
+ }
+
+ if (be32_to_cpu(cfg.cmd) != DST_REMOTE_CFG)
+ return -EINVAL;
+
+ n->size = be64_to_cpu(cfg.sector);
+
+ return 0;
+}
+
+static int dst_setup_remote(struct dst_node *n, struct dst_ctl *ctl,
+ struct dst_remote_ctl *r)
+{
+ int err;
+ struct socket *sock;
+
+ err = sock_create(r->addr.sa_family, r->type, r->proto, &sock);
+ if (err < 0)
+ goto err_out_exit;
+
+ sock->sk->sk_sndtimeo = sock->sk->sk_rcvtimeo =
+ msecs_to_jiffies(DST_DEFAULT_TIMEO);
+
+ err = sock->ops->connect(sock, (struct sockaddr *)&r->addr,
+ r->addr.sa_data_len, 0);
+ if (err)
+ goto err_out_destroy;
+
+ if (!n->size) {
+ err = dst_request_remote_config(n, sock);
+ if (err)
+ goto err_out_destroy;
+ }
+
+ n->state = kst_data_state_init(n, sock);
+ if (IS_ERR(n->state)) {
+ err = PTR_ERR(n->state);
+ goto err_out_destroy;
+ }
+
+ return 0;
+
+err_out_destroy:
+ sock_release(sock);
+err_out_exit:
+ return err;
+}
+
+/*
+ * This function inserts node into storage.
+ */
+static int dst_insert_node(struct dst_node *n)
+{
+ int err;
+ struct dst_storage *st = n->st;
+ struct dst_node *dn;
+
+ err = st->alg->ops->add_node(n);
+ if (err)
+ goto err_out_exit;
+
+ err = dst_node_sysfs_init(n);
+ if (err)
+ goto err_out_remove_node;
+
+ mutex_lock(&st->tree_lock);
+ dn = dst_storage_tree_add(n, st);
+ if (dn) {
+ err = -EINVAL;
+ dn->size = st->disk_size;
+ if (dn->start == n->start) {
+ err = 0;
+ n->shared_head = dst_node_get(dn);
+ atomic_inc(&dn->shared_num);
+ list_add_tail(&n->shared, &dn->shared);
+ }
+ }
+ mutex_unlock(&st->tree_lock);
+ if (err)
+ goto err_out_sysfs_exit;
+
+ if (n->priv_callback)
+ n->priv_callback(n);
+
+ return 0;
+
+err_out_sysfs_exit:
+ dst_node_sysfs_exit(n);
+err_out_remove_node:
+ st->alg->ops->del_node(n);
+err_out_exit:
+ return err;
+}
+
+static struct dst_node *dst_alloc_node(struct dst_ctl *ctl,
+ void (*cleanup)(struct dst_node *))
+{
+ struct dst_storage *st;
+ struct dst_node *n;
+
+ st = dst_get_storage(ctl->st, ctl->alg, 1);
+ if (!st)
+ goto err_out_exit;
+
+ n = kzalloc(sizeof(struct dst_node), GFP_KERNEL);
+ if (!n)
+ goto err_out_put_storage;
+
+ n->w = kst_main_worker;
+ n->st = st;
+ n->cleanup = cleanup;
+ n->start = ctl->start;
+ n->size = ctl->size;
+ INIT_LIST_HEAD(&n->shared);
+ n->shared_head = NULL;
+ atomic_set(&n->shared_num, 0);
+ atomic_set(&n->refcnt, 1);
+
+ return n;
+
+err_out_put_storage:
+ mutex_lock(&dst_storage_lock);
+ list_del_init(&st->entry);
+ mutex_unlock(&dst_storage_lock);
+
+ dst_put_storage(st);
+err_out_exit:
+ return NULL;
+}
+
+/*
+ * Control callback for userspace commands to setup
+ * different nodes and start/stop array.
+ */
+static int dst_add_remote(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_remote_ctl *rctl = data;
+
+ if (len != sizeof(struct dst_remote_ctl))
+ return -EINVAL;
+
+ n = dst_alloc_node(ctl, &dst_cleanup_remote);
+ if (!n)
+ return -ENOMEM;
+
+ err = dst_setup_remote(n, ctl, rctl);
+ if (err < 0)
+ goto err_out_free;
+
+ err = dst_insert_node(n);
+ if (err)
+ goto err_out_free;
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ return err;
+}
+
+static int dst_add_local_export(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_le_template tmp;
+
+ if (len < sizeof(struct dst_local_export_ctl))
+ return -EINVAL;
+
+ tmp.le = data;
+
+ len -= sizeof(struct dst_local_export_ctl);
+ data += sizeof(struct dst_local_export_ctl);
+
+ if (len != tmp.le->secure_attr_num * sizeof(struct dst_secure_user))
+ return -EINVAL;
+
+ tmp.data = data;
+
+ n = dst_alloc_node(ctl, &dst_cleanup_local_export);
+ if (!n)
+ return -EINVAL;
+
+ err = dst_setup_local_export(n, ctl, &tmp);
+ if (err < 0)
+ goto err_out_free;
+
+ err = dst_insert_node(n);
+ if (err)
+ goto err_out_free;
+
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ return err;
+}
+
+static int dst_add_local(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_local_ctl *lctl = data;
+
+ if (len != sizeof(struct dst_local_ctl))
+ return -EINVAL;
+
+ n = dst_alloc_node(ctl, &dst_cleanup_local);
+ if (!n)
+ return -EINVAL;
+
+ err = dst_setup_local(n, ctl, lctl);
+ if (err < 0)
+ goto err_out_free;
+
+ err = dst_insert_node(n);
+ if (err)
+ goto err_out_free;
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ return err;
+}
+
+static int dst_del_node(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_node *n;
+ struct dst_storage *st;
+ int err = -ENODEV;
+
+ if (len)
+ return -EINVAL;
+
+ st = dst_get_storage(ctl->st, ctl->alg, 0);
+ if (!st)
+ goto err_out_exit;
+
+ mutex_lock(&st->tree_lock);
+ n = dst_storage_tree_del(st, ctl->start);
+ mutex_unlock(&st->tree_lock);
+ if (!n)
+ goto err_out_put;
+
+ dst_node_put(n);
+ dst_put_storage(st);
+
+ return 0;
+
+err_out_put:
+ dst_put_storage(st);
+err_out_exit:
+ return err;
+}
+
+static int dst_start_storage(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_storage *st;
+
+ if (len)
+ return -EINVAL;
+
+ st = dst_get_storage(ctl->st, ctl->alg, 0);
+ if (!st)
+ return -ENODEV;
+
+ mutex_lock(&st->tree_lock);
+ if (!(st->flags & DST_ST_STARTED)) {
+ set_capacity(st->disk, st->disk_size);
+ add_disk(st->disk);
+ st->flags |= DST_ST_STARTED;
+ dprintk("%s: STARTED st: %p, disk_size: %llu.\n",
+ __func__, st, st->disk_size);
+ }
+ mutex_unlock(&st->tree_lock);
+
+ dst_put_storage(st);
+
+ return 0;
+}
+
+static int dst_stop_storage(struct dst_ctl *ctl, void *data, unsigned int len)
+{
+ struct dst_storage *st;
+
+ if (len)
+ return -EINVAL;
+
+ st = dst_get_storage(ctl->st, ctl->alg, 0);
+ if (!st)
+ return -ENODEV;
+
+ dprintk("%s: STOPPED storage: %s.\n", __func__, st->name);
+
+ dst_storage_sysfs_exit(st);
+
+ mutex_lock(&dst_storage_lock);
+ list_del_init(&st->entry);
+ mutex_unlock(&dst_storage_lock);
+
+ if (st->flags & DST_ST_STARTED)
+ dst_remove_disk(st);
+
+ dst_remove_all_nodes(st);
+ dst_put_storage(st); /* One reference got above */
+ dst_put_storage(st); /* Another reference set during initialization */
+
+ return 0;
+}
+
+typedef int (*dst_command_func)(struct dst_ctl *ctl, void *data, unsigned int len);
+
+/*
+ * List of userspace commands.
+ */
+static dst_command_func dst_commands[] = {
+ [DST_ADD_REMOTE] = &dst_add_remote,
+ [DST_ADD_LOCAL] = &dst_add_local,
+ [DST_ADD_LOCAL_EXPORT] = &dst_add_local_export,
+ [DST_DEL_NODE] = &dst_del_node,
+ [DST_START_STORAGE] = &dst_start_storage,
+ [DST_STOP_STORAGE] = &dst_stop_storage,
+};
+
+/*
+ * Configuration parser.
+ */
+static void cn_dst_callback(void *data)
+{
+ struct dst_ctl *ctl;
+ struct cn_msg *msg = data;
+
+ if (msg->len < sizeof(struct dst_ctl))
+ return;
+
+ ctl = (struct dst_ctl *)msg->data;
+
+ if (ctl->cmd >= DST_CMD_MAX)
+ return;
+
+ dst_commands[ctl->cmd](ctl, msg->data + sizeof(struct dst_ctl),
+ msg->len - sizeof(struct dst_ctl));
+}
+
+static int dst_sysfs_init(void)
+{
+ return bus_register(&dst_dev_bus_type);
+}
+
+static void dst_sysfs_exit(void)
+{
+ bus_unregister(&dst_dev_bus_type);
+}
+
+static int __init dst_sys_init(void)
+{
+ int err = -ENOMEM;
+
+ dst_request_cache = kmem_cache_create("dst", sizeof(struct dst_request),
+ 0, 0, NULL, NULL);
+ if (!dst_request_cache)
+ return -ENOMEM;
+
+ dst_bio_set = bioset_create(32, 32);
+ if (!dst_bio_set)
+ goto err_out_destroy;
+
+ err = register_blkdev(dst_major, DST_NAME);
+ if (err < 0)
+ goto err_out_destroy_bioset;
+ if (err)
+ dst_major = err;
+
+ err = dst_sysfs_init();
+ if (err)
+ goto err_out_unregister;
+
+ kst_main_worker = kst_worker_init(0);
+ if (IS_ERR(kst_main_worker)) {
+ err = PTR_ERR(kst_main_worker);
+ goto err_out_sysfs_exit;
+ }
+
+ err = cn_add_callback(&cn_dst_id, "DST", cn_dst_callback);
+ if (err)
+ goto err_out_worker_exit;
+
+ return 0;
+
+err_out_worker_exit:
+ kst_worker_exit(kst_main_worker);
+err_out_sysfs_exit:
+ dst_sysfs_exit();
+err_out_unregister:
+ unregister_blkdev(dst_major, DST_NAME);
+err_out_destroy_bioset:
+ bioset_free(dst_bio_set);
+err_out_destroy:
+ kmem_cache_destroy(dst_request_cache);
+ return err;
+}
+
+static void __exit dst_sys_exit(void)
+{
+ cn_del_callback(&cn_dst_id);
+ dst_sysfs_exit();
+ unregister_blkdev(dst_major, DST_NAME);
+ kst_exit_all();
+ bioset_free(dst_bio_set);
+ kmem_cache_destroy(dst_request_cache);
+}
+
+module_init(dst_sys_init);
+module_exit(dst_sys_exit);
+
+MODULE_DESCRIPTION("Distributed storage");
+MODULE_AUTHOR("Evgeniy Polyakov <johnpol@....mipt.ru>");
+MODULE_LICENSE("GPL");
--
Evgeniy Polyakov
-
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