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SubjectDistributed storage.
Hi.

I'm pleased to announce first release of the distributed storage
subsystem, which allows to form a storage on top of remote and local
nodes, which in turn can be exported to another storage as a node to
form tree-like storages.

There is number of main features, this device supports:
* zero additional allocations in the common fast path (only one per node if
network queue is full) not counting network alocations
* zero-copy sending (except header) if supported by device using sendpage()
* ability to use any implemented algorithm (linear algo implemented)
* plugable mapping algorithms
* failover recovery in case of broken link (reconnection if remote node
is down)
* ability to suspend remote node for maintenance without breaking dataflow
to another nodes (if supported by algorithm and block layer) and
without turning down main node
* initial autoconfiguration (ability to request remote node size and use
that dynamic data during array setup time)
* non-blocking network data processing (except headers, which are
sent/received in blocking mode, can be simply changed to non-blocking
too by increasing request size to store state) without busy loops
checking return valu of processing functions. Non-blocking data
processing is based on ->poll() state machine with only one working
thread per storage.
* support for any kind of network media (not limited to tcp or inet
protocols) higher MAC layer (socket layer), data consistensy must be
part of the protocol (i.e. will lose data with UDP in favour of
performance)
* no need for any special tools for data processing (like special
userspace applications) except for configuration
* userspace and kernelspace targets. Userspace target can work on top of
usual files. (Windows or any other OS userspace target support can be
trivially added on request)

Compared to other similar approaches namely iSCSI and NBD,
there are following advantages:
* non-blocking processing without busy loops (compared to both above)
* small, plugable architecture
* failover recovery (reconnect to remote target)
* autoconfiguration (full absence in NBD and/or device mapper on top of it)
* no additional allocatins (not including network part) - at least two in
device mapper for fast path
* very simple - try to compare with iSCSI
* works with different network protocols
* storage can be formed on top of remote nodes and be exported
simultaneously (iSCSI is peer-to-peer only, NBD requires device
mapper and is synchronous)

TODO list currently includes following main items:
* redundancy algorithm (drop me a request of your own, but it is highly
unlikley that Reed-Solomon based will ever be used - it is too slow
for distributed RAID, I consider WEAVER codes)
* extended autoconfiguration
* move away from ioctl based configuration

Patch, userspace configuration utility and userspace target can be found
on project homepage:

http://tservice.net.ru/~s0mbre/old/?section=projects&item=dst

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

drivers/block/Kconfig | 2 +
drivers/block/Makefile | 1 +
drivers/block/dst/Kconfig | 12 +
drivers/block/dst/Makefile | 5 +
drivers/block/dst/alg_linear.c | 348 ++++++++++
drivers/block/dst/dcore.c | 1222 ++++++++++++++++++++++++++++++++++
drivers/block/dst/kst.c | 1437 ++++++++++++++++++++++++++++++++++++++++
include/linux/dst.h | 282 ++++++++
8 files changed, 3309 insertions(+), 0 deletions(-)
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index b4c8319..ca6592d 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -451,6 +451,8 @@ config ATA_OVER_ETH
This driver provides Support for ATA over Ethernet block
devices like the Coraid EtherDrive (R) Storage Blade.

+source "drivers/block/dst/Kconfig"
+
source "drivers/s390/block/Kconfig"

endmenu
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-$(CONFIG_DST) += dst/
diff --git a/drivers/block/dst/Kconfig b/drivers/block/dst/Kconfig
new file mode 100644
index 0000000..874d2e4
--- /dev/null
+++ b/drivers/block/dst/Kconfig
@@ -0,0 +1,12 @@
+config DST
+ tristate "Distributed storage"
+ depends on NET
+ ---help---
+ This driver allows to create a distributed storage.
+
+config DST_ALG_LINEAR
+ tristate "Linear distribution algorithm"
+ depends on DST
+ ---help---
+ This module allows to create linear mapping of the nodes
+ in the distributed storage.
diff --git a/drivers/block/dst/Makefile b/drivers/block/dst/Makefile
new file mode 100644
index 0000000..48b7777
--- /dev/null
+++ b/drivers/block/dst/Makefile
@@ -0,0 +1,5 @@
+obj-$(CONFIG_DST) += dst.o
+
+dst-y := dcore.o kst.o
+
+obj-$(CONFIG_DST_ALG_LINEAR) += alg_linear.o
diff --git a/drivers/block/dst/alg_linear.c b/drivers/block/dst/alg_linear.c
new file mode 100644
index 0000000..9a134fc
--- /dev/null
+++ b/drivers/block/dst/alg_linear.c
@@ -0,0 +1,348 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@2ka.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/dst.h>
+
+static struct dst_alg *alg_linear;
+static struct bio_set *dst_linear_bio_set;
+
+/*
+ * This callback is invoked when node is removed from storage.
+ */
+static void dst_linear_del_node(struct dst_node *n)
+{
+}
+
+/*
+ * This callback is invoked when node is added to storage.
+ */
+static int dst_linear_add_node(struct dst_node *n)
+{
+ struct dst_storage *st = n->st;
+
+ n->start = st->disk_size;
+ st->disk_size += n->size;
+
+ return 0;
+}
+
+/*
+ * 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_linear_end_io(struct bio *bio, unsigned int size, int err)
+{
+ struct bio *orig_bio = bio->bi_private;
+
+ if (err)
+ printk("%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;
+}
+
+static void dst_linear_destructor(struct bio *bio)
+{
+ bio_free(bio, dst_linear_bio_set);
+}
+
+/*
+ * This function sends processing request down to block layer (for local node)
+ * or to network state machine (for remote node).
+ */
+static int dst_linear_node_push(struct dst_request *req)
+{
+ int err = 0;
+
+ if (req->state->node->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 = req->state->node->bdev;
+ bio->bi_sector = req->start;
+ generic_make_request(bio);
+ goto out_put;
+ } else {
+ struct bio *clone = bio_alloc_bioset(GFP_NOIO,
+ bio->bi_max_vecs, dst_linear_bio_set);
+ struct bio_vec *bv;
+
+ err = -ENOMEM;
+ if (!clone)
+ goto out_put;
+
+ 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);
+
+ __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 = req->state->node->bdev;
+ clone->bi_sector = req->start;
+ clone->bi_destructor = dst_linear_destructor;
+ clone->bi_private = bio;
+ clone->bi_size = req->orig_size;
+ clone->bi_end_io = &dst_linear_end_io;
+
+ generic_make_request(clone);
+ err = 0;
+ goto out_put;
+ }
+ }
+
+ err = req->state->node->state->ops->push(req);
+
+out_put:
+ dst_node_put(req->state->node);
+ return err;
+}
+
+/*
+ * This callback is invoked from block layer request processing function,
+ * its task is to remap block request to different nodes.
+ */
+static int dst_linear_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.bio = bio;
+
+ req.size = bio->bi_size;
+ req.orig_size = bio->bi_size;
+ req.idx = 0;
+ req.num = bio->bi_vcnt;
+
+ /*
+ * Common fast path - block request does not cross
+ * boundaries between nodes.
+ */
+ if (likely(bio->bi_sector + bio_sectors <= n->start + n->size))
+ return dst_linear_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;
+
+ 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_linear_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.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;
+
+ 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_linear_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;
+}
+
+/*
+ * Failover callback - it is invoked each time error happens during
+ * request processing.
+ */
+static int dst_linear_error(struct kst_state *st, int err)
+{
+ if (!err)
+ return 0;
+
+ if (err == -ECONNRESET || err == -EPIPE) {
+ if (st->ops->recovery(st, err)) {
+ err = st->ops->recovery(st, err);
+ if (err) {
+ set_bit(DST_NODE_FROZEN, &st->node->flags);
+ } else {
+ clear_bit(DST_NODE_FROZEN, &st->node->flags);
+ }
+ err = 0;
+ }
+ }
+
+ return err;
+}
+
+static struct dst_alg_ops alg_linear_ops = {
+ .remap = dst_linear_remap,
+ .add_node = dst_linear_add_node,
+ .del_node = dst_linear_del_node,
+ .error = dst_linear_error,
+ .owner = THIS_MODULE,
+};
+
+static int __devinit alg_linear_init(void)
+{
+ dst_linear_bio_set = bioset_create(32, 32);
+ if (!dst_linear_bio_set)
+ panic("bio: can't allocate bios\n");
+
+ alg_linear = dst_alloc_alg("alg_linear", &alg_linear_ops);
+ if (!alg_linear)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __devexit alg_linear_exit(void)
+{
+ dst_remove_alg(alg_linear);
+ bioset_free(dst_linear_bio_set);
+}
+
+module_init(alg_linear_init);
+module_exit(alg_linear_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
+MODULE_DESCRIPTION("Linear distributed algorithm.");
diff --git a/drivers/block/dst/dcore.c b/drivers/block/dst/dcore.c
new file mode 100644
index 0000000..fd11f86
--- /dev/null
+++ b/drivers/block/dst/dcore.c
@@ -0,0 +1,1222 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@2ka.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/miscdevice.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;
+
+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
+};
+
+/*
+ * 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 = st->alg->ops->remap(st, bio);
+
+ dprintk("%s: end: st: %p, bio: %p, err: %d.\n",
+ __func__, st, bio, err);
+
+ if (err) {
+ printk("%s: remap failed: bio: %p, err: %d.\n",
+ __func__, bio, err);
+ bio_endio(bio, bio->bi_size, -EIO);
+ }
+ 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;
+
+ 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 = 0;
+ 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;
+ 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);
+ 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", n->start);
+ 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:
+ 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)
+{
+ dprintk("%s: node: %p.\n", __func__, n);
+ n->st->alg->ops->del_node(n);
+ 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);
+}
+
+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 {
+ atomic_inc(&dn->refcnt);
+ return 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 int 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 -EEXIST;
+ }
+
+ rb_link_node(&new->tree_node, parent, n);
+ rb_insert_color(&new->tree_node, &st->tree_root);
+
+ return 0;
+}
+
+/*
+ * 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_local_export_ctl *le)
+{
+ int err;
+
+ err = dst_setup_local(n, ctl, &le->lctl);
+ if (err)
+ goto err_out_exit;
+
+ n->state = kst_listener_state_init(kst_main_worker, n, le);
+ 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;
+ }
+
+ 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(kst_main_worker, 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;
+
+ err = st->alg->ops->add_node(n);
+ if (err)
+ return err;
+
+ err = dst_node_sysfs_init(n);
+ if (err)
+ goto err_out_remove_node;
+
+ mutex_lock(&st->tree_lock);
+ err = dst_storage_tree_add(n, st);
+ mutex_unlock(&st->tree_lock);
+ if (err)
+ goto err_out_sysfs_exit;
+
+ return 0;
+
+err_out_sysfs_exit:
+ dst_node_sysfs_exit(n);
+err_out_remove_node:
+ st->alg->ops->del_node(n);
+ 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->st = st;
+ n->cleanup = cleanup;
+ n->start = ctl->start;
+ n->size = ctl->size;
+ 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 __user *data)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_remote_ctl rctl;
+
+ if (copy_from_user(&rctl, data, sizeof(struct dst_remote_ctl)))
+ return -EFAULT;
+
+ 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 __user *data)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_local_export_ctl le;
+
+ if (copy_from_user(&le, data, sizeof(struct dst_local_export_ctl)))
+ return -EFAULT;
+
+ n = dst_alloc_node(ctl, &dst_cleanup_local_export);
+ if (!n)
+ return -EINVAL;
+
+ err = dst_setup_local_export(n, ctl, &le);
+ 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 __user *data)
+{
+ struct dst_node *n;
+ int err;
+ struct dst_local_ctl lctl;
+
+ if (copy_from_user(&lctl, data, sizeof(struct dst_local_ctl)))
+ return -EFAULT;
+
+ 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 __user *data)
+{
+ struct dst_node *n;
+ struct dst_storage *st;
+ int err = -ENODEV;
+
+ 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 __user *data)
+{
+ struct dst_storage *st;
+
+ 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 __user *data)
+{
+ struct dst_storage *st;
+
+ 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 __user *data);
+
+/*
+ * 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,
+};
+
+/*
+ * Move to connector for configuration is in TODO list.
+ */
+static int dst_ioctl(struct inode *inode, struct file *file,
+ unsigned int command, unsigned long data)
+{
+ struct dst_ctl ctl;
+ unsigned int cmd = _IOC_NR(command);
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (_IOC_TYPE(command) != DST_IOCTL)
+ return -ENOTTY;
+
+ if (cmd >= DST_CMD_MAX)
+ return -EINVAL;
+
+ if (copy_from_user(&ctl, (void __user *)data, sizeof(struct dst_ctl)))
+ return -EFAULT;
+
+ data += sizeof(struct dst_ctl);
+
+ return dst_commands[cmd](&ctl, (void __user *)data);
+}
+
+static const struct file_operations dst_fops = {
+ .ioctl = dst_ioctl,
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice dst_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = DST_NAME,
+ .fops = &dst_fops
+};
+
+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 __devinit dst_sys_init(void)
+{
+ int err;
+
+ dst_request_cache = kmem_cache_create("dst", sizeof(struct dst_request),
+ 0, 0, NULL, NULL);
+ if (!dst_request_cache)
+ return -ENOMEM;
+
+ err = register_blkdev(dst_major, DST_NAME);
+ if (err < 0)
+ goto err_out_destroy;
+ 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 = misc_register(&dst_misc);
+ 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:
+ kmem_cache_destroy(dst_request_cache);
+ return err;
+}
+
+static void __devexit dst_sys_exit(void)
+{
+ misc_deregister(&dst_misc);
+ dst_sysfs_exit();
+ unregister_blkdev(dst_major, DST_NAME);
+ kst_exit_all();
+ 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@2ka.mipt.ru>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/block/dst/kst.c b/drivers/block/dst/kst.c
new file mode 100644
index 0000000..7193d4c
--- /dev/null
+++ b/drivers/block/dst/kst.c
@@ -0,0 +1,1437 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@2ka.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/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/socket.h>
+#include <linux/kthread.h>
+#include <linux/net.h>
+#include <linux/in.h>
+#include <linux/poll.h>
+#include <linux/bio.h>
+#include <linux/dst.h>
+
+#include <net/sock.h>
+
+struct kst_poll_helper
+{
+ poll_table pt;
+ struct kst_state *st;
+};
+
+static LIST_HEAD(kst_worker_list);
+static DEFINE_MUTEX(kst_worker_mutex);
+
+/*
+ * This function creates bound socket for local export node.
+ */
+static int kst_sock_create(struct kst_state *st, struct saddr *addr,
+ int type, int proto, int backlog)
+{
+ int err;
+
+ err = sock_create(addr->sa_family, type, proto, &st->socket);
+ if (err)
+ goto err_out_exit;
+
+ err = st->socket->ops->bind(st->socket, (struct sockaddr *)addr,
+ addr->sa_data_len);
+
+ err = st->socket->ops->listen(st->socket, backlog);
+ if (err)
+ goto err_out_release;
+
+ st->socket->sk->sk_allocation = GFP_NOIO;
+
+ return 0;
+
+err_out_release:
+ sock_release(st->socket);
+err_out_exit:
+ return err;
+}
+
+static void kst_sock_release(struct kst_state *st)
+{
+ if (st->socket) {
+ sock_release(st->socket);
+ st->socket = NULL;
+ }
+}
+
+static void kst_wake(struct kst_state *st)
+{
+ struct kst_worker *w = st->w;
+ unsigned long flags;
+
+ spin_lock_irqsave(&w->ready_lock, flags);
+ if (list_empty(&st->ready_entry))
+ list_add_tail(&st->ready_entry, &w->ready_list);
+ spin_unlock_irqrestore(&w->ready_lock, flags);
+
+ wake_up(&w->wait);
+}
+
+/*
+ * Polling machinery.
+ */
+static int kst_state_wake_callback(wait_queue_t *wait, unsigned mode,
+ int sync, void *key)
+{
+ struct kst_state *st = container_of(wait, struct kst_state, wait);
+ kst_wake(st);
+ return 1;
+}
+
+static void kst_queue_func(struct file *file, wait_queue_head_t *whead,
+ poll_table *pt)
+{
+ struct kst_state *st = container_of(pt, struct kst_poll_helper, pt)->st;
+
+ st->whead = whead;
+ init_waitqueue_func_entry(&st->wait, kst_state_wake_callback);
+ add_wait_queue(whead, &st->wait);
+}
+
+static void kst_poll_exit(struct kst_state *st)
+{
+ if (st->whead) {
+ remove_wait_queue(st->whead, &st->wait);
+ st->whead = NULL;
+ }
+}
+
+/*
+ * This function removes request from state tree and ordering list.
+ */
+static void kst_del_req(struct dst_request *req)
+{
+ struct kst_state *st = req->state;
+
+ rb_erase(&req->request_entry, &st->request_root);
+ RB_CLEAR_NODE(&req->request_entry);
+ list_del_init(&req->request_list_entry);
+}
+
+static struct dst_request *kst_req_first(struct kst_state *st)
+{
+ struct dst_request *req = NULL;
+
+ if (!list_empty(&st->request_list))
+ req = list_entry(st->request_list.next, struct dst_request,
+ request_list_entry);
+ return req;
+}
+
+/*
+ * This function dequeues first request from the queue and tree.
+ */
+static struct dst_request *kst_dequeue_req(struct kst_state *st)
+{
+ struct dst_request *req;
+
+ mutex_lock(&st->request_lock);
+ req = kst_req_first(st);
+ if (req)
+ kst_del_req(req);
+ mutex_unlock(&st->request_lock);
+ return req;
+}
+
+static inline int dst_compare_request_id(struct dst_request *old,
+ struct dst_request *new)
+{
+ int cmd = 0;
+
+ if (old->start + to_sector(old->orig_size) <= new->start)
+ cmd = 1;
+ if (old->start >= new->start + to_sector(new->orig_size))
+ cmd = -1;
+
+ dprintk("%s: old: op: %lu, start: %llu, size: %llu, off: %u, "
+ "new: op: %lu, start: %llu, size: %llu, off: %u, cmp: %d.\n",
+ __func__, bio_rw(old->bio), old->start, old->orig_size,
+ old->offset,
+ bio_rw(new->bio), new->start, new->orig_size,
+ new->offset, cmd);
+
+ return cmd;
+}
+
+/*
+ * This function enqueues request into tree, indexed by start of the request,
+ * and also puts request into ordered queue.
+ */
+static int kst_enqueue_req(struct kst_state *st, struct dst_request *req)
+{
+ struct rb_node **n = &st->request_root.rb_node, *parent = NULL;
+ struct dst_request *old = NULL;
+ int cmp;
+
+ while (*n) {
+ parent = *n;
+ old = rb_entry(parent, struct dst_request, request_entry);
+
+ cmp = dst_compare_request_id(old, req);
+ if (cmp < 0)
+ n = &parent->rb_left;
+ else if (cmp > 0)
+ n = &parent->rb_right;
+ else
+ return -EEXIST;
+ }
+
+ rb_link_node(&req->request_entry, parent, n);
+ rb_insert_color(&req->request_entry, &st->request_root);
+
+ if (req->size != req->orig_size)
+ list_add(&req->request_list_entry, &st->request_list);
+ else
+ list_add_tail(&req->request_list_entry, &st->request_list);
+ return 0;
+}
+
+/*
+ * BIOs for local exporting node are freed via this function.
+ */
+static void kst_export_put_bio(struct bio *bio)
+{
+ int i;
+ struct bio_vec *bv;
+
+ dprintk("%s: bio: %p, size: %u, idx: %d, num: %d.\n",
+ __func__, bio, bio->bi_size, bio->bi_idx,
+ bio->bi_vcnt);
+
+ bio_for_each_segment(bv, bio, i)
+ __free_page(bv->bv_page);
+ bio_put(bio);
+}
+
+/*
+ * This is a generic request completion function.
+ * If it is local export node, state machine is different,
+ * see details below.
+ */
+static void kst_complete_req(struct dst_request *req, int err)
+{
+ if (err)
+ printk("%s: freeing bio: %p, req: %p, size: %llu, "
+ "orig_size: %llu, bi_size: %u, err: %d, flags: %u.\n",
+ __func__, req->bio, req, req->size, req->orig_size,
+ req->bio->bi_size, err, req->flags);
+
+ if (req->flags & DST_REQ_EXPORT) {
+ if (req->flags & DST_REQ_EXPORT_WRITE) {
+ req->bio->bi_rw = WRITE;
+ generic_make_request(req->bio);
+ } else
+ kst_export_put_bio(req->bio);
+ } else {
+ bio_endio(req->bio, req->orig_size, (err)?-EIO:0);
+ }
+ dprintk("%s: free req: %p, pool: %p.\n",
+ __func__, req, req->state->w->req_pool);
+ mempool_free(req, req->state->w->req_pool);
+}
+
+static void kst_flush_requests(struct kst_state *st)
+{
+ struct dst_request *req;
+
+ while ((req = kst_dequeue_req(st)) != NULL)
+ kst_complete_req(req, -EIO);
+}
+
+static int kst_poll_init(struct kst_state *st)
+{
+ struct kst_poll_helper ph;
+
+ ph.st = st;
+ init_poll_funcptr(&ph.pt, &kst_queue_func);
+
+ st->socket->ops->poll(NULL, st->socket, &ph.pt);
+ return 0;
+}
+
+/*
+ * Main state creation function.
+ * It creates new state according to given operations
+ * and links it into worker structure and node.
+ */
+struct kst_state *kst_state_init(struct kst_worker *w, struct dst_node *node,
+ struct kst_state_ops *ops, void *data)
+{
+ struct kst_state *st;
+ int err;
+
+ st = kzalloc(sizeof(struct kst_state), GFP_KERNEL);
+ if (!st)
+ return ERR_PTR(-ENOMEM);
+
+ st->node = node;
+ st->ops = ops;
+ st->w = w;
+ INIT_LIST_HEAD(&st->ready_entry);
+ INIT_LIST_HEAD(&st->entry);
+ st->request_root.rb_node = NULL;
+ INIT_LIST_HEAD(&st->request_list);
+ mutex_init(&st->request_lock);
+
+ err = st->ops->init(st, data);
+ if (err)
+ goto err_out_free;
+ mutex_lock(&w->state_mutex);
+ list_add_tail(&st->entry, &w->state_list);
+ mutex_unlock(&w->state_mutex);
+
+ kst_wake(st);
+
+ return st;
+
+err_out_free:
+ kfree(st);
+ return ERR_PTR(err);
+}
+
+/*
+ * This function is called when node is removed,
+ * or when state is destroyed for connected to local exporting
+ * node client.
+ */
+void kst_state_exit(struct kst_state *st)
+{
+ struct kst_worker *w = st->w;
+
+ dprintk("%s: st: %p.\n", __func__, st);
+
+ mutex_lock(&w->state_mutex);
+ list_del_init(&st->entry);
+ mutex_unlock(&w->state_mutex);
+
+ st->ops->exit(st);
+ kfree(st);
+}
+
+/*
+ * This is main state processing function.
+ * It tries to complete request and invoke appropriate
+ * callbacks in case of errors or successfull operation finish.
+ */
+static int kst_thread_process_state(struct kst_state *st)
+{
+ int err, empty;
+ unsigned int revents;
+ struct dst_request *req, *tmp;
+
+ mutex_lock(&st->request_lock);
+ if (st->ops->ready) {
+ err = st->ops->ready(st);
+ if (err) {
+ mutex_unlock(&st->request_lock);
+ if (err < 0)
+ kst_state_exit(st);
+ return err;
+ }
+ }
+
+ err = 0;
+ empty = 1;
+ req = NULL;
+ list_for_each_entry_safe(req, tmp, &st->request_list,
+ request_list_entry) {
+ empty = 0;
+ revents = st->socket->ops->poll(st->socket->file,
+ st->socket, NULL);
+ dprintk("\n%s: st: %p, revents: %x.\n", __func__, st, revents);
+ if (!revents)
+ break;
+ err = req->callback(req, revents);
+ dprintk("%s: callback returned, st: %p, err: %d.\n",
+ __func__, st, err);
+ if (err)
+ break;
+ }
+ mutex_unlock(&st->request_lock);
+
+ dprintk("%s: req: %p, err: %d.\n", __func__, req, err);
+ if (err < 0) {
+ err = st->node->st->alg->ops->error(st, err);
+ if (err && (st != st->node->state)) {
+ dprintk("%s: err: %d, st: %p, node->state: %p.\n",
+ __func__, err, st, st->node->state);
+ /*
+ * Accepted client has state not related to storage
+ * node, so it must be freed explicitely.
+ */
+
+ kst_state_exit(st);
+ return err;
+ }
+
+ kst_wake(st);
+ }
+
+ if (list_empty(&st->request_list) && !empty)
+ kst_wake(st);
+
+ return err;
+}
+
+/*
+ * Main worker thread - one per storage.
+ */
+static int kst_thread_func(void *data)
+{
+ struct kst_worker *w = data;
+ struct kst_state *st;
+ unsigned long flags;
+ int err = 0;
+
+ while (!kthread_should_stop()) {
+ wait_event_interruptible_timeout(w->wait,
+ !list_empty(&w->ready_list) ||
+ kthread_should_stop(),
+ HZ);
+
+ st = NULL;
+ spin_lock_irqsave(&w->ready_lock, flags);
+ if (!list_empty(&w->ready_list)) {
+ st = list_entry(w->ready_list.next, struct kst_state,
+ ready_entry);
+ list_del_init(&st->ready_entry);
+ }
+ spin_unlock_irqrestore(&w->ready_lock, flags);
+
+ if (!st)
+ continue;
+
+ err = kst_thread_process_state(st);
+ }
+
+ return err;
+}
+
+/*
+ * Worker initialization - this object will host andprocess all states,
+ * which in turn host requests for remote targets.
+ */
+struct kst_worker *kst_worker_init(int id)
+{
+ struct kst_worker *w;
+ int err;
+
+ w = kzalloc(sizeof(struct kst_worker), GFP_KERNEL);
+ if (!w)
+ return ERR_PTR(-ENOMEM);
+
+ w->id = id;
+ init_waitqueue_head(&w->wait);
+ spin_lock_init(&w->ready_lock);
+ mutex_init(&w->state_mutex);
+
+ INIT_LIST_HEAD(&w->ready_list);
+ INIT_LIST_HEAD(&w->state_list);
+
+ w->req_pool = mempool_create_slab_pool(256, dst_request_cache);
+ if (!w->req_pool) {
+ err = -ENOMEM;
+ goto err_out_free;
+ }
+
+ w->thread = kthread_run(&kst_thread_func, w, "kst%d", w->id);
+ if (IS_ERR(w->thread)) {
+ err = PTR_ERR(w->thread);
+ goto err_out_destroy;
+ }
+
+ mutex_lock(&kst_worker_mutex);
+ list_add_tail(&w->entry, &kst_worker_list);
+ mutex_unlock(&kst_worker_mutex);
+
+ return w;
+
+err_out_destroy:
+ mempool_destroy(w->req_pool);
+err_out_free:
+ kfree(w);
+ return ERR_PTR(err);
+}
+
+void kst_worker_exit(struct kst_worker *w)
+{
+ struct kst_state *st, *n;
+
+ mutex_lock(&kst_worker_mutex);
+ list_del(&w->entry);
+ mutex_unlock(&kst_worker_mutex);
+
+ kthread_stop(w->thread);
+
+ list_for_each_entry_safe(st, n, &w->state_list, entry) {
+ kst_state_exit(st);
+ }
+
+ mempool_destroy(w->req_pool);
+ kfree(w);
+}
+
+/*
+ * Common state exit callback.
+ * Removes itself from worker's list of states,
+ * releases socket and flushes all requests.
+ */
+static void kst_common_exit(struct kst_state *st)
+{
+ unsigned long flags;
+
+ dprintk("%s: st: %p.\n", __func__, st);
+ kst_poll_exit(st);
+
+ spin_lock_irqsave(&st->w->ready_lock, flags);
+ list_del_init(&st->ready_entry);
+ spin_unlock_irqrestore(&st->w->ready_lock, flags);
+
+ kst_sock_release(st);
+ kst_flush_requests(st);
+}
+
+/*
+ * Header sending function - may block.
+ */
+static int kst_data_send_header(struct kst_state *st,
+ struct dst_remote_request *r)
+{
+ struct msghdr msg;
+ struct kvec iov;
+
+ iov.iov_base = r;
+ 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 | MSG_NOSIGNAL;
+
+ return kernel_sendmsg(st->socket, &msg, &iov, 1, iov.iov_len);
+}
+
+/*
+ * BIO vector receiving function - does not block, but may sleep because
+ * of scheduling policy.
+ */
+static int kst_data_recv_bio_vec(struct kst_state *st, struct bio_vec *bv,
+ unsigned int offset, unsigned int size)
+{
+ struct msghdr msg;
+ struct kvec iov;
+ void *kaddr;
+ int err;
+
+ kaddr = kmap(bv->bv_page);
+
+ iov.iov_base = kaddr + bv->bv_offset + offset;
+ iov.iov_len = size;
+
+ 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_DONTWAIT | MSG_NOSIGNAL;
+
+ err = kernel_recvmsg(st->socket, &msg, &iov, 1, iov.iov_len,
+ msg.msg_flags);
+ kunmap(bv->bv_page);
+
+ return err;
+}
+
+/*
+ * BIO vector sending function - does not block, but may sleep because
+ * of scheduling policy.
+ */
+static int kst_data_send_bio_vec(struct kst_state *st, struct bio_vec *bv,
+ unsigned int offset, unsigned int size)
+{
+ return kernel_sendpage(st->socket, bv->bv_page,
+ bv->bv_offset + offset, size,
+ MSG_DONTWAIT | MSG_NOSIGNAL);
+}
+
+typedef int (*kst_data_process_bio_vec_t)(struct kst_state *st,
+ struct bio_vec *bv, unsigned int offset, unsigned int size);
+
+/*
+ * @req: processing request.
+ * Contains BIO and all related to its processing info.
+ *
+ * This function sends or receives requested number of pages from given BIO.
+ *
+ * In case of errors negative return value is returned and @size,
+ * @index and @off are set to the:
+ * - number of bytes not yet processed (i.e. the rest of the bytes to be
+ * processed).
+ * - index of the last bio_vec started to be processed (header sent).
+ * - offset of the first byte to be processed in the bio_vec.
+ *
+ * If there are no errors, zero is returned.
+ * -EAGAIN is not an error and is transformed into zero return value,
+ * called must check if @size is zero, in that case whole BIO is processed
+ * and thus bio_endio() can be called, othervise new request must be allocated
+ * to be processed later.
+ */
+static int kst_data_process_bio(struct dst_request *req)
+{
+ int err = -ENOSPC, partial = (req->size != req->orig_size);
+ struct dst_remote_request r;
+ kst_data_process_bio_vec_t func;
+ unsigned int cur_size;
+
+ r.flags = cpu_to_be32(((unsigned long)req->bio) & 0xffffffff);
+
+ if (bio_rw(req->bio) == WRITE) {
+ r.cmd = cpu_to_be32(DST_WRITE);
+ func = kst_data_send_bio_vec;
+ } else {
+ r.cmd = cpu_to_be32(DST_READ);
+ func = kst_data_recv_bio_vec;
+ }
+
+ dprintk("%s: start: [%c], start: %llu, idx: %d, num: %d, "
+ "size: %llu, offset: %u.\n",
+ __func__, (bio_rw(req->bio) == WRITE)?'W':'R',
+ req->start, req->idx, req->num, req->size, req->offset);
+
+ while (req->idx < req->num) {
+ struct bio_vec *bv = bio_iovec_idx(req->bio, req->idx);
+
+ cur_size = min_t(u64, bv->bv_len - req->offset, req->size);
+
+ BUG_ON(cur_size == 0);
+
+ if (!(req->flags & DST_REQ_HEADER_SENT)) {
+ r.sector = cpu_to_be64(req->start);
+ r.offset = cpu_to_be32(bv->bv_offset + req->offset);
+ r.size = cpu_to_be32(cur_size);
+
+ err = kst_data_send_header(req->state, &r);
+ if (err != sizeof(struct dst_remote_request)) {
+ dprintk("%s: %d/%d: header: start: %llu, "
+ "bv_offset: %u, bv_len: %u, "
+ "a offset: %u, offset: %u, "
+ "cur_size: %u, err: %d.\n",
+ __func__, req->idx, req->num,
+ req->start, bv->bv_offset, bv->bv_len,
+ bv->bv_offset + req->offset,
+ req->offset, cur_size, err);
+ if (err >= 0)
+ err = -EINVAL;
+ break;
+ }
+
+ req->flags |= DST_REQ_HEADER_SENT;
+ }
+
+ err = func(req->state, bv, req->offset, cur_size);
+ if (err <= 0)
+ break;
+
+ req->offset += err;
+ req->size -= err;
+ req->start += to_sector(err);
+
+ if (req->offset != bv->bv_len) {
+ dprintk("%s: %d/%d: this: start: %llu, bv_offset: %u, "
+ "bv_len: %u, a offset: %u, offset: %u, "
+ "cur_size: %u, err: %d.\n",
+ __func__, req->idx, req->num, req->start,
+ bv->bv_offset, bv->bv_len,
+ bv->bv_offset + req->offset,
+ req->offset, cur_size, err);
+ err = -EAGAIN;
+ break;
+ }
+ req->offset = 0;
+ req->idx++;
+ req->flags &= ~DST_REQ_HEADER_SENT;
+ }
+
+ if (err <= 0 && err != -EAGAIN) {
+ if (err == 0)
+ err = -ECONNRESET;
+ } else
+ err = 0;
+
+ if (req->size) {
+ req->state->flags |= KST_FLAG_PARTIAL;
+ } else if (partial) {
+ req->state->flags &= ~KST_FLAG_PARTIAL;
+ }
+
+ if (err < 0 || (req->idx == req->num && req->size)) {
+ dprintk("%s: return: idx: %d, num: %d, offset: %u, "
+ "size: %llu, err: %d.\n",
+ __func__, req->idx, req->num, req->offset,
+ req->size, err);
+ }
+ dprintk("%s: end: start: %llu, idx: %d, num: %d, "
+ "size: %llu, offset: %u.\n",
+ __func__, req->start, req->idx, req->num,
+ req->size, req->offset);
+
+
+ return err;
+}
+
+/*
+ * This callback is invoked by worker thread to process given request.
+ */
+static int kst_data_callback(struct dst_request *req, unsigned int revents)
+{
+ int err;
+
+ dprintk("%s: req: %p, num: %d, idx: %d, bio: %p, "
+ "revents: %x, flags: %x.\n",
+ __func__, req, req->num, req->idx, req->bio,
+ revents, req->flags);
+
+ if (req->flags & DST_REQ_EXPORT_READ)
+ return 1;
+
+ err = kst_data_process_bio(req);
+ if (err < 0)
+ goto err_out;
+
+ if (!req->size) {
+ dprintk("%s: complete: req: %p, bio: %p.\n",
+ __func__, req, req->bio);
+ kst_del_req(req);
+ kst_complete_req(req, 0);
+ return 0;
+ }
+
+ if (revents & (POLLERR | POLLHUP | POLLRDHUP)) {
+ err = -EPIPE;
+ goto err_out;
+ }
+
+ return 1;
+
+err_out:
+ return err;
+}
+
+#define KST_CONG_COMPLETED (0)
+#define KST_CONG_NOT_FOUND (1)
+#define KST_CONG_QUEUE (-1)
+
+/*
+ * kst_congestion - checks for data congestion, i.e. the case, when given
+ * block request crosses an area of the another block request which
+ * is not yet sent to the remote node.
+ *
+ * @req: dst request containing block io related information.
+ *
+ * Return value:
+ * %KST_CONG_COMPLETED - congestion was found and processed,
+ * bio must be ended, request is completed.
+ * %KST_CONG_NOT_FOUND - no congestion found,
+ * request must be processed as usual
+ * %KST_CONG_QUEUE - congestion has been found, but bio is not completed,
+ * new request must be allocated and processed.
+ */
+static int kst_congestion(struct dst_request *req)
+{
+ int cmp, i;
+ struct kst_state *st = req->state;
+ struct rb_node *n = st->request_root.rb_node;
+ struct dst_request *old = NULL, *dst_req, *src_req;
+
+ while (n) {
+ src_req = rb_entry(n, struct dst_request, request_entry);
+ cmp = dst_compare_request_id(src_req, req);
+
+ if (cmp < 0)
+ n = n->rb_left;
+ else if (cmp > 0)
+ n = n->rb_right;
+ else {
+ old = src_req;
+ break;
+ }
+ }
+
+ if (likely(!old))
+ return KST_CONG_NOT_FOUND;
+
+ dprintk("%s: old: op: %lu, start: %llu, size: %llu, off: %u, "
+ "new: op: %lu, start: %llu, size: %llu, off: %u.\n",
+ __func__, bio_rw(old->bio), old->start, old->orig_size,
+ old->offset,
+ bio_rw(req->bio), req->start, req->orig_size, req->offset);
+
+ if ((bio_rw(old->bio) != WRITE) && (bio_rw(req->bio) != WRITE)) {
+ return KST_CONG_QUEUE;
+ }
+
+ if (unlikely(req->offset != old->offset))
+ return KST_CONG_QUEUE;
+
+ src_req = old;
+ dst_req = req;
+ if (bio_rw(req->bio) == WRITE) {
+ dst_req = old;
+ src_req = req;
+ }
+
+ /* Actually we could partially complete new request by copying
+ * part of the first one, but not now, consider this as a
+ * (low-priority) todo item.
+ */
+ if (src_req->start + src_req->orig_size <
+ dst_req->start + dst_req->orig_size)
+ return KST_CONG_QUEUE;
+
+ /*
+ * So, only process if new request is differnt from old one,
+ * or subsequent write, i.e.:
+ * - not completed write and request to read
+ * - not completed read and request to write
+ * - not completed write and request to (over)write
+ */
+ for (i=old->idx; i<old->num; ++i) {
+ struct bio_vec *bv_src, *bv_dst;
+ void *src, *dst;
+ u64 len;
+
+ bv_src = bio_iovec_idx(src_req->bio, i);
+ bv_dst = bio_iovec_idx(dst_req->bio, i);
+
+ if (unlikely(bv_dst->bv_offset != bv_src->bv_offset))
+ return KST_CONG_QUEUE;
+
+ if (unlikely(bv_dst->bv_len != bv_src->bv_len))
+ return KST_CONG_QUEUE;
+
+ src = kmap_atomic(bv_src->bv_page, KM_USER0);
+ dst = kmap_atomic(bv_dst->bv_page, KM_USER1);
+
+ len = min_t(u64, bv_dst->bv_len, dst_req->size);
+
+ memcpy(dst + bv_dst->bv_offset, src + bv_src->bv_offset, len);
+
+ kunmap_atomic(src, KM_USER0);
+ kunmap_atomic(dst, KM_USER1);
+
+ dst_req->idx++;
+ dst_req->size -= len;
+ dst_req->offset = 0;
+ dst_req->start += to_sector(len);
+
+ if (!dst_req->size)
+ break;
+ }
+
+ if (req == dst_req)
+ return KST_CONG_COMPLETED;
+
+ kst_del_req(dst_req);
+ kst_complete_req(dst_req, 0);
+
+ return KST_CONG_NOT_FOUND;
+}
+
+static struct dst_request *dst_clone_request(struct dst_request *req)
+{
+ struct dst_request *new_req;
+
+ new_req = mempool_alloc(req->state->w->req_pool, GFP_NOIO);
+ if (!new_req)
+ return NULL;
+
+ dprintk("%s: req: %p, new_req: %p, bio: %p.\n",
+ __func__, req, new_req, req->bio);
+
+ RB_CLEAR_NODE(&new_req->request_entry);
+
+ new_req->bio = req->bio;
+ new_req->state = req->state;
+ new_req->idx = req->idx;
+ new_req->num = req->num;
+ new_req->size = req->size;
+ new_req->orig_size = req->orig_size;
+ new_req->offset = req->offset;
+ new_req->start = req->start;
+ new_req->flags = req->flags;
+
+ return new_req;
+}
+
+/*
+ * This is main data processing function, eventually invoked from block layer.
+ * It tries to complte request, but if it is about to block, it allocates
+ * new request and queues it to main worker to be processed when events allow.
+ */
+static int kst_data_push(struct dst_request *req)
+{
+ struct kst_state *st = req->state;
+ struct dst_request *new_req;
+ unsigned int revents;
+ int err, locked = 0;
+
+ dprintk("%s: start: %llu, size: %llu, bio: %p.\n",
+ __func__, req->start, req->size, req->bio);
+
+ if (mutex_trylock(&st->request_lock)) {
+ locked = 1;
+
+ if (st->flags & (KST_FLAG_PARTIAL | DST_REQ_ALWAYS_QUEUE))
+ goto alloc_new_req;
+
+ err = kst_congestion(req);
+ if (err == KST_CONG_COMPLETED)
+ goto out_bio_endio;
+
+ if (err == KST_CONG_NOT_FOUND) {
+ revents = st->socket->ops->poll(NULL, st->socket, NULL);
+ dprintk("%s: st: %p, bio: %p, revents: %x.\n",
+ __func__, st, req->bio, revents);
+ if (revents & POLLOUT) {
+ err = kst_data_process_bio(req);
+ if (err < 0)
+ goto out_unlock;
+
+ if (!req->size) {
+ err = 0;
+ goto out_bio_endio;
+ }
+ }
+ }
+ }
+
+alloc_new_req:
+ err = -ENOMEM;
+ new_req = dst_clone_request(req);
+ if (!new_req)
+ goto out_unlock;
+
+ new_req->callback = &kst_data_callback;
+
+ if (!locked)
+ mutex_lock(&st->request_lock);
+ locked = 1;
+
+ err = kst_enqueue_req(st, new_req);
+ mutex_unlock(&st->request_lock);
+ if (err) {
+ printk("%s: free req: %p, pool: %p.\n",
+ __func__, new_req, st->w->req_pool);
+ printk("%s: free [%c], start: %llu, idx: %d, "
+ "num: %d, size: %llu, offset: %u, err: %d.\n",
+ __func__, (bio_rw(req->bio) == WRITE)?'W':'R',
+ req->start, req->idx, req->num, req->size,
+ req->offset, err);
+ mempool_free(new_req, st->w->req_pool);
+ goto err_out;
+ }
+
+ kst_wake(st);
+
+ return 0;
+
+out_bio_endio:
+ if (err)
+ printk("%s: freeing bio: %p, bi_size: %u, orig_size: %llu.\n",
+ __func__, req->bio, req->bio->bi_size, req->orig_size);
+ bio_endio(req->bio, req->orig_size, err);
+out_unlock:
+ mutex_unlock(&st->request_lock);
+ locked = 0;
+err_out:
+ if (err) {
+ err = st->node->st->alg->ops->error(st, err);
+ if (!err)
+ goto alloc_new_req;
+ }
+
+ if (err)
+ printk("%s: [%c], start: %llu, idx: %d, num: %d, "
+ "size: %llu, offset: %u, err: %d.\n",
+ __func__, (bio_rw(req->bio) == WRITE)?'W':'R',
+ req->start, req->idx, req->num, req->size,
+ req->offset, err);
+ kst_wake(st);
+ return err;
+}
+
+/*
+ * Remote node initialization callback.
+ */
+static int kst_data_init(struct kst_state *st, void *data)
+{
+ int err;
+
+ st->socket = data;
+ st->socket->sk->sk_allocation = GFP_NOIO;
+ /*
+ * Why not?
+ */
+ st->socket->sk->sk_sndbuf = st->socket->sk->sk_sndbuf = 1024*1024*10;
+
+ err = kst_poll_init(st);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+/*
+ * Remote node recovery function - tries to reconnect to given target.
+ */
+static int kst_data_recovery(struct kst_state *st, int err)
+{
+ struct socket *sock;
+ struct sockaddr addr;
+ int addrlen;
+ struct dst_request *req;
+
+ if (err != -ECONNRESET && err != -EPIPE) {
+ dprintk("%s: state %p does not know how "
+ "to recover from error %d.\n",
+ __func__, st, err);
+ return err;
+ }
+
+ err = sock_create(st->socket->ops->family, st->socket->type,
+ st->socket->sk->sk_protocol, &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->getname(st->socket, &addr, &addrlen, 2);
+ if (err)
+ goto err_out_destroy;
+
+ err = sock->ops->connect(sock, &addr, addrlen, 0);
+ if (err)
+ goto err_out_destroy;
+
+ kst_poll_exit(st);
+ kst_sock_release(st);
+
+ mutex_lock(&st->request_lock);
+ err = st->ops->init(st, sock);
+ if (!err) {
+ /*
+ * After reconnection is completed all requests
+ * must be resent from the state they were finished previously,
+ * but with new headers.
+ */
+ list_for_each_entry(req, &st->request_list, request_list_entry)
+ req->flags &= ~DST_REQ_HEADER_SENT;
+ }
+ mutex_unlock(&st->request_lock);
+ if (err < 0)
+ goto err_out_destroy;
+
+ kst_wake(st);
+ printk("%s: recovery completed.\n", __func__);
+
+ return 0;
+
+err_out_destroy:
+ sock_release(sock);
+err_out_exit:
+ dprintk("%s: reovery failed: st: %p, err: %d.\n", __func__, st, err);
+ return err;
+}
+
+static inline void kst_convert_header(struct dst_remote_request *r)
+{
+ r->cmd = be32_to_cpu(r->cmd);
+ r->sector = be64_to_cpu(r->sector);
+ r->offset = be32_to_cpu(r->offset);
+ r->size = be32_to_cpu(r->size);
+ r->flags = be32_to_cpu(r->flags);
+}
+
+/*
+ * Local exporting node end IO callbacks.
+ */
+static int kst_export_write_end_io(struct bio *bio, unsigned int size, int err)
+{
+ dprintk("%s: bio: %p, size: %u, idx: %d, num: %d, err: %d.\n",
+ __func__, bio, bio->bi_size, bio->bi_idx, bio->bi_vcnt, err);
+
+ if (bio->bi_size)
+ return 1;
+
+ kst_export_put_bio(bio);
+ return 0;
+}
+
+static int kst_export_read_end_io(struct bio *bio, unsigned int size, int err)
+{
+ struct dst_request *req = bio->bi_private;
+ struct kst_state *st = req->state;
+
+ dprintk("%s: bio: %p, req: %p, size: %u, idx: %d, num: %d, err: %d.\n",
+ __func__, bio, req, bio->bi_size, bio->bi_idx,
+ bio->bi_vcnt, err);
+
+ if (bio->bi_size)
+ return 1;
+
+ bio->bi_size = req->size = req->orig_size;
+ bio->bi_rw = WRITE;
+ req->flags &= ~DST_REQ_EXPORT_READ;
+ kst_wake(st);
+ return 0;
+}
+
+/*
+ * This callback is invoked each time new request from remote
+ * node to given local export node is received.
+ * It allocates new block IO request and queues it for processing.
+ */
+static int kst_export_ready(struct kst_state *st)
+{
+ struct dst_remote_request r;
+ struct msghdr msg;
+ struct kvec iov;
+ struct bio *bio;
+ int err, nr, i;
+ struct dst_request *req;
+ sector_t data_size;
+ unsigned int revents = st->socket->ops->poll(NULL, st->socket, NULL);
+
+ if (revents & (POLLERR | POLLHUP)) {
+ err = -EPIPE;
+ goto err_out_exit;
+ }
+
+ if (!(revents & POLLIN) || !list_empty(&st->request_list))
+ return 0;
+
+ iov.iov_base = &r;
+ 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 | MSG_NOSIGNAL;
+
+ err = kernel_recvmsg(st->socket, &msg, &iov, 1,
+ iov.iov_len, msg.msg_flags);
+ if (err != sizeof(struct dst_remote_request)) {
+ err = -EINVAL;
+ goto err_out_exit;
+ }
+
+ kst_convert_header(&r);
+
+ dprintk("\n%s: cmd: %u, sector: %llu, size: %u, "
+ "flags: %x, offset: %u.\n",
+ __func__, r.cmd, r.sector, r.size, r.flags, r.offset);
+
+ /*
+ * Does not support autoconfig yet.
+ */
+ err = -EINVAL;
+ if (r.cmd != DST_READ && r.cmd != DST_WRITE)
+ goto err_out_exit;
+
+ data_size = get_capacity(st->node->bdev->bd_disk);
+ if ((signed)(r.sector + to_sector(r.size)) < 0 ||
+ (signed)(r.sector + to_sector(r.size)) > data_size ||
+ (signed)r.sector > data_size)
+ goto err_out_exit;
+
+ nr = r.size/PAGE_SIZE + 1;
+
+ while (r.size) {
+ int nr_pages = min(BIO_MAX_PAGES, nr);
+ unsigned int size;
+ struct page *page;
+
+ err = -ENOMEM;
+ req = mempool_alloc(st->w->req_pool, GFP_NOIO);
+ if (!req)
+ goto err_out_exit;
+
+ dprintk("%s: alloc req: %p, pool: %p.\n",
+ __func__, req, st->w->req_pool);
+
+ bio = bio_alloc(GFP_NOIO, nr_pages);
+ if (!bio)
+ goto err_out_free_req;
+
+ req->flags = DST_REQ_EXPORT | DST_REQ_HEADER_SENT;
+ req->bio = bio;
+ req->state = st;
+ req->callback = &kst_data_callback;
+
+ /*
+ * Yes, looks a bit weird.
+ * Logic is simple - for local exporting node all operations
+ * are reversed compared to usual nodes, since usual nodes
+ * process remote data and local export node process remote
+ * requests, so that writing data means sending data to
+ * remote node and receiving on the local export one.
+ *
+ * So, to process writing to the exported node we need first to
+ * receive data from the net (i.e. to perform READ operation
+ * in terms of usual node), and then put it to the storage
+ * (WRITE command, so it will be changed before calling
+ * generic_make_request()).
+ *
+ * To process read request from the exported node we need
+ * first to read it from storage (READ command for BIO)
+ * and then send it over the net (perform WRITE operation
+ * in terms of network).
+ */
+ if (r.cmd == DST_WRITE) {
+ req->flags |= DST_REQ_EXPORT_WRITE;
+ bio->bi_end_io = kst_export_write_end_io;
+ } else {
+ req->flags |= DST_REQ_EXPORT_READ;
+ bio->bi_end_io = kst_export_read_end_io;
+ }
+ bio->bi_rw = READ;
+ bio->bi_private = req;
+ bio->bi_sector = r.sector;
+ bio->bi_bdev = st->node->bdev;
+
+ for (i=0; i<nr_pages; ++i) {
+ page = alloc_page(GFP_NOIO);
+ if (!page)
+ break;
+
+ size = min_t(u32, PAGE_SIZE, r.size);
+
+ err = bio_add_page(bio, page, size, r.offset);
+ dprintk("%s: %d/%d: page: %p, size: %u, offset: %u, "
+ "err: %d.\n",
+ __func__, i, nr_pages, page, size,
+ r.offset, err);
+ if (err <= 0)
+ break;
+
+ if (err == size) {
+ r.offset = 0;
+ nr--;
+ } else {
+ r.offset += err;
+ }
+
+ r.size -= err;
+ r.sector += to_sector(err);
+
+ if (!r.size)
+ break;
+ }
+
+ if (!bio->bi_vcnt) {
+ err = -ENOMEM;
+ goto err_out_put;
+ }
+
+ req->size = req->orig_size = bio->bi_size;
+ req->start = bio->bi_sector;
+ req->idx = 0;
+ req->num = bio->bi_vcnt;
+
+ dprintk("%s: submitting: bio: %p, req: %p, start: %llu, "
+ "size: %llu, idx: %d, num: %d, offset: %u, err: %d.\n",
+ __func__, bio, req, req->start, req->size,
+ req->idx, req->num, req->offset, err);
+
+ err = kst_enqueue_req(st, req);
+ if (err)
+ goto err_out_put;
+
+ if (r.cmd == DST_READ) {
+ generic_make_request(bio);
+ }
+ }
+
+ kst_wake(st);
+ return 0;
+
+err_out_put:
+ bio_put(bio);
+err_out_free_req:
+ dprintk("%s: free req: %p, pool: %p.\n",
+ __func__, req, st->w->req_pool);
+ mempool_free(req, st->w->req_pool);
+err_out_exit:
+ dprintk("%s: error: %d.\n", __func__, err);
+ return err;
+}
+
+static void kst_export_exit(struct kst_state *st)
+{
+ struct dst_node *n = st->node;
+
+ dprintk("%s: st: %p.\n", __func__, st);
+
+ kst_common_exit(st);
+ dst_node_put(n);
+}
+
+static struct kst_state_ops kst_data_export_ops = {
+ .init = &kst_data_init,
+ .push = &kst_data_push,
+ .exit = &kst_export_exit,
+ .ready = &kst_export_ready,
+};
+
+/*
+ * This callback is invoked each time listening socket for
+ * given local export node becomes ready.
+ * It creates new state for connected client and queues for processing.
+ */
+static int kst_listen_ready(struct kst_state *st)
+{
+ struct socket *newsock;
+ struct saddr addr;
+ struct kst_state *newst;
+ int err;
+ unsigned int revents;
+
+ revents = st->socket->ops->poll(NULL, st->socket, NULL);
+ if (!(revents & POLLIN))
+ return 1;
+
+ err = sock_create(st->socket->ops->family, st->socket->type,
+ st->socket->sk->sk_protocol, &newsock);
+ if (err)
+ goto err_out_exit;
+
+ err = st->socket->ops->accept(st->socket, newsock, 0);
+ if (err)
+ goto err_out_put;
+
+ if (newsock->ops->getname(newsock, (struct sockaddr *)&addr,
+ (int *)&addr.sa_data_len, 2) < 0) {
+ err = -ECONNABORTED;
+ goto err_out_put;
+ }
+
+ if (st->socket->ops->family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
+ printk("%s: Client: %u.%u.%u.%u:%d.\n", __func__,
+ NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port));
+ } else if (st->socket->ops->family == AF_INET6) {
+ struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&addr;
+ printk("%s: Client: %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x:%d",
+ __func__, NIP6(sin->sin6_addr), ntohs(sin->sin6_port));
+ }
+
+ atomic_inc(&st->node->refcnt);
+ newst = kst_state_init(st->w, st->node, &kst_data_export_ops, newsock);
+ if (IS_ERR(newst)) {
+ err = PTR_ERR(newst);
+ goto err_out_put;
+ }
+
+ return 0;
+
+err_out_put:
+ dst_node_put(st->node);
+ sock_release(newsock);
+err_out_exit:
+ return err;
+}
+
+static int kst_listen_init(struct kst_state *st, void *data)
+{
+ int err;
+ struct dst_local_export_ctl *le = data;
+
+ err = kst_sock_create(st, &le->rctl.addr, le->rctl.type,
+ le->rctl.proto, le->backlog);
+ if (err)
+ goto err_out_exit;
+
+ err = kst_poll_init(st);
+ if (err)
+ goto err_out_release;
+
+ return 0;
+
+err_out_release:
+ kst_sock_release(st);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Operations for different types of states.
+ * There are three:
+ * data state - created for remote node, when distributed storage connects
+ * to remote node, which contain data.
+ * listen state - created for local export node, when remote distributed
+ * storage's node connects to given node to get/put data.
+ * data export state - created for each client connected to above listen
+ * state.
+ */
+static struct kst_state_ops kst_listen_ops = {
+ .init = &kst_listen_init,
+ .exit = &kst_common_exit,
+ .ready = &kst_listen_ready,
+};
+static struct kst_state_ops kst_data_ops = {
+ .init = &kst_data_init,
+ .push = &kst_data_push,
+ .exit = &kst_common_exit,
+ .recovery = &kst_data_recovery,
+};
+
+struct kst_state *kst_listener_state_init(struct kst_worker *w,
+ struct dst_node *node, struct dst_local_export_ctl *le)
+{
+ return kst_state_init(w, node, &kst_listen_ops, le);
+}
+
+struct kst_state *kst_data_state_init(struct kst_worker *w,
+ struct dst_node *node, struct socket *newsock)
+{
+ return kst_state_init(w, node, &kst_data_ops, newsock);
+}
+
+/*
+ * Remove all workers and associated states.
+ */
+void kst_exit_all(void)
+{
+ struct kst_worker *w, *n;
+
+ list_for_each_entry_safe(w, n, &kst_worker_list, entry) {
+ kst_worker_exit(w);
+ }
+}
diff --git a/include/linux/dst.h b/include/linux/dst.h
new file mode 100644
index 0000000..b92fb55
--- /dev/null
+++ b/include/linux/dst.h
@@ -0,0 +1,282 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <johnpol@2ka.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.
+ */
+
+#ifndef __DST_H
+#define __DST_H
+
+#include <linux/types.h>
+
+#define DST_NAMELEN 32
+#define DST_NAME "dst"
+#define DST_IOCTL 0xba
+
+enum {
+ DST_DEL_NODE = 0, /* Remove node with given id from storage */
+ DST_ADD_REMOTE, /* Add remote node with given id to the storage */
+ DST_ADD_LOCAL, /* Add local node with given id to the storage */
+ DST_ADD_LOCAL_EXPORT, /* Add local node with given id to the storage to be exported and used by remote peers */
+ DST_START_STORAGE, /* Array is ready and storage can be started, if there will be new nodes
+ * added to the storage, they will be checked against existing size and
+ * probably be dropped (for example in mirror format when new node has smaller
+ * size than array created) or inserted.
+ */
+ DST_STOP_STORAGE, /* Remove array and all nodes. */
+ DST_CMD_MAX
+};
+
+#define DST_CTL_FLAGS_REMOTE (1<<0)
+#define DST_CTL_FLAGS_EXPORT (1<<1)
+
+struct dst_ctl
+{
+ char st[DST_NAMELEN];
+ char alg[DST_NAMELEN];
+ __u32 flags;
+ __u64 start, size;
+};
+
+struct dst_local_ctl
+{
+ char name[DST_NAMELEN];
+};
+
+#define SADDR_MAX_DATA 128
+
+struct saddr {
+ unsigned short sa_family; /* address family, AF_xxx */
+ char sa_data[SADDR_MAX_DATA]; /* 14 bytes of protocol address */
+ unsigned short sa_data_len; /* Number of bytes used in sa_data */
+};
+
+struct dst_remote_ctl
+{
+ __u16 type;
+ __u16 proto;
+ struct saddr addr;
+};
+
+struct dst_local_export_ctl
+{
+ __u32 backlog;
+ struct dst_local_ctl lctl;
+ struct dst_remote_ctl rctl;
+};
+
+
+enum {
+ DST_REMOTE_CFG = 1, /* Request remote configuration */
+ DST_WRITE, /* Writing */
+ DST_READ, /* Reading */
+ DST_NCMD_MAX,
+};
+
+struct dst_remote_request
+{
+ __u32 cmd;
+ __u32 flags;
+ __u64 sector;
+ __u32 offset;
+ __u32 size;
+};
+
+#ifdef __KERNEL__
+
+#include <linux/rbtree.h>
+#include <linux/net.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/mempool.h>
+#include <linux/device.h>
+
+//#define DST_DEBUG
+
+#ifdef DST_DEBUG
+#define dprintk(f, a...) printk(f, ##a)
+#else
+#define dprintk(f, a...) do {} while (0)
+#endif
+
+struct kst_worker
+{
+ struct list_head entry;
+
+ struct list_head state_list;
+ struct mutex state_mutex;
+
+ struct list_head ready_list;
+ spinlock_t ready_lock;
+
+ mempool_t *req_pool;
+
+ struct task_struct *thread;
+
+ wait_queue_head_t wait;
+
+ int id;
+};
+
+struct kst_state;
+struct dst_node;
+
+#define DST_REQ_HEADER_SENT (1<<0)
+#define DST_REQ_EXPORT (1<<1)
+#define DST_REQ_EXPORT_WRITE (1<<2)
+#define DST_REQ_EXPORT_READ (1<<3)
+#define DST_REQ_ALWAYS_QUEUE (1<<4)
+
+struct dst_request
+{
+ struct rb_node request_entry;
+ struct list_head request_list_entry;
+ struct bio *bio;
+ struct kst_state *state;
+
+ u32 flags;
+
+ int (*callback)(struct dst_request *, unsigned int);
+
+ u64 size, orig_size, start;
+ int idx, num;
+ u32 offset;
+};
+
+struct kst_state_ops
+{
+ int (*init)(struct kst_state *, void *);
+ int (*push)(struct dst_request *req);
+ int (*ready)(struct kst_state *);
+ int (*recovery)(struct kst_state *, int err);
+ void (*exit)(struct kst_state *);
+};
+
+#define KST_FLAG_PARTIAL (1<<0)
+
+struct kst_state
+{
+ struct list_head entry;
+ struct list_head ready_entry;
+
+ wait_queue_t wait;
+ wait_queue_head_t *whead;
+
+ struct dst_node *node;
+ struct kst_worker *w;
+ struct socket *socket;
+
+ u32 flags;
+
+ struct rb_root request_root;
+ struct mutex request_lock;
+ struct list_head request_list;
+
+ struct kst_state_ops *ops;
+};
+
+#define DST_DEFAULT_TIMEO 2000
+
+struct dst_storage;
+
+struct dst_alg_ops
+{
+ int (*add_node)(struct dst_node *n);
+ void (*del_node)(struct dst_node *n);
+ int (*remap)(struct dst_storage *st, struct bio *bio);
+ int (*error)(struct kst_state *state, int err);
+ struct module *owner;
+};
+
+struct dst_alg
+{
+ struct list_head entry;
+ char name[DST_NAMELEN];
+ atomic_t refcnt;
+ struct dst_alg_ops *ops;
+};
+
+#define DST_ST_STARTED (1<<0)
+
+struct dst_storage
+{
+ struct list_head entry;
+ char name[DST_NAMELEN];
+ struct dst_alg *alg;
+ atomic_t refcnt;
+ struct mutex tree_lock;
+ struct rb_root tree_root;
+
+ request_queue_t *queue;
+ struct gendisk *disk;
+
+ long flags;
+ u64 disk_size;
+
+ struct device device;
+};
+
+#define DST_NODE_FROZEN 0
+
+struct dst_node
+{
+ struct rb_node tree_node;
+ struct block_device *bdev;
+ struct dst_storage *st;
+ struct kst_state *state;
+
+ atomic_t refcnt;
+
+ void (*cleanup)(struct dst_node *);
+
+ long flags;
+
+ u64 start, size;
+
+ struct device device;
+};
+
+struct kst_state *kst_state_init(struct kst_worker *w, struct dst_node *node,
+ struct kst_state_ops *ops, void *data);
+void kst_state_exit(struct kst_state *st);
+
+struct kst_worker *kst_worker_init(int id);
+void kst_worker_exit(struct kst_worker *w);
+
+struct kst_state *kst_listener_state_init(struct kst_worker *w, struct dst_node *node,
+ struct dst_local_export_ctl *le);
+struct kst_state *kst_data_state_init(struct kst_worker *w, struct dst_node *node,
+ struct socket *newsock);
+
+void kst_exit_all(void);
+
+struct dst_alg *dst_alloc_alg(char *name, struct dst_alg_ops *ops);
+void dst_remove_alg(struct dst_alg *alg);
+
+struct dst_node *dst_storage_tree_search(struct dst_storage *st, u64 start);
+
+void dst_node_put(struct dst_node *n);
+
+extern struct kmem_cache *dst_request_cache;
+
+static inline sector_t to_sector(unsigned long n)
+{
+ return (n >> 9);
+}
+
+static inline unsigned long to_bytes(sector_t n)
+{
+ return (n << 9);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __DST_H */

--
Evgeniy Polyakov
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