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Message-ID: <20071018191755.GC848@2ka.mipt.ru>
Date: Thu, 18 Oct 2007 23:17:55 +0400
From: Evgeniy Polyakov <johnpol@....mipt.ru>
To: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [2/3] Distributed storage. Network state machine.
Signed-off-by: Evgeniy Polyakov <johnpol@....mipt.ru>
diff --git a/drivers/block/dst/kst.c b/drivers/block/dst/kst.c
new file mode 100644
index 0000000..b0608c9
--- /dev/null
+++ b/drivers/block/dst/kst.c
@@ -0,0 +1,1606 @@
+/*
+ * 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/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;
+ }
+}
+
+void kst_wake(struct kst_state *st)
+{
+ if (st) {
+ struct kst_worker *w = st->node->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);
+ }
+}
+EXPORT_SYMBOL_GPL(kst_wake);
+
+/*
+ * 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.
+ */
+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);
+}
+EXPORT_SYMBOL_GPL(kst_del_req);
+
+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.
+ */
+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, err = 0;
+
+ 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 {
+ printk("%s: [%c] old_req: %p, start: %llu, "
+ "size: %llu.\n",
+ __func__,
+ (bio_rw(old->bio) == WRITE)?'W':'R',
+ old, old->start, old->orig_size);
+ err = -EEXIST;
+ break;
+ }
+ }
+
+ if (!err) {
+ 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 err;
+}
+EXPORT_SYMBOL_GPL(kst_enqueue_req);
+
+/*
+ * 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 for requests,
+ * queued for async processing.
+ * If it is local export node, state machine is different,
+ * see details below.
+ */
+void kst_complete_req(struct dst_request *req, int err)
+{
+ dprintk("%s: 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 {
+ req->bio_endio(req, err);
+ }
+ dst_free_request(req);
+}
+EXPORT_SYMBOL_GPL(kst_complete_req);
+
+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.
+ */
+static struct kst_state *kst_state_init(struct dst_node *node,
+ unsigned int permissions,
+ 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->permissions = permissions;
+ st->node = node;
+ st->ops = ops;
+ 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(&node->w->state_mutex);
+ list_add_tail(&st->entry, &node->w->state_list);
+ mutex_unlock(&node->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->node->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);
+
+ st->node->state = NULL;
+
+ kfree(st);
+}
+
+static int kst_error(struct kst_state *st, int err)
+{
+ if ((err == -ECONNRESET || err == -EPIPE) && st->ops->recovery(st, err))
+ err = st->ops->recovery(st, err);
+
+ return st->node->st->alg->ops->error(st, err);
+}
+
+/*
+ * 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 = kst_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->node->w->ready_lock, flags);
+ list_del_init(&st->ready_entry);
+ spin_unlock_irqrestore(&st->node->w->ready_lock, flags);
+
+ kst_sock_release(st);
+ kst_flush_requests(st);
+}
+
+/*
+ * Listen socket contains security attributes in request_list,
+ * so it can not be flushed via usual way.
+ */
+static void kst_listen_flush(struct kst_state *st)
+{
+ struct dst_secure *s, *tmp;
+
+ list_for_each_entry_safe(s, tmp, &st->request_list, sec_entry) {
+ list_del(&s->sec_entry);
+ kfree(s);
+ }
+}
+
+static void kst_listen_exit(struct kst_state *st)
+{
+ kst_listen_flush(st);
+ kst_common_exit(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 req->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);
+
+ if (cur_size == 0) {
+ printk("%s: %d/%d: start: %llu, "
+ "bv_offset: %u, bv_len: %u, "
+ "req_offset: %u, req_size: %llu, "
+ "req: %p, bio: %p, err: %d.\n",
+ __func__, req->idx, req->num, req->start,
+ bv->bv_offset, bv->bv_len,
+ req->offset, req->size,
+ req, req->bio, err);
+ BUG();
+ }
+
+ 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;
+
+ 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;
+
+ req->start += to_sector(bv->bv_len);
+ }
+
+ 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;
+}
+
+void kst_bio_endio(struct dst_request *req, int err)
+{
+ if (err)
+ printk("%s: freeing bio: %p, bi_size: %u, "
+ "orig_size: %llu, req: %p.\n",
+ __func__, req->bio, req->bio->bi_size, req->orig_size, req);
+ bio_endio(req->bio, req->orig_size, err);
+}
+EXPORT_SYMBOL_GPL(kst_bio_endio);
+
+/*
+ * This callback is invoked by worker thread to process given request.
+ */
+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;
+}
+EXPORT_SYMBOL_GPL(kst_data_callback);
+
+#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;
+}
+
+struct dst_request *dst_clone_request(struct dst_request *req, mempool_t *pool)
+{
+ struct dst_request *new_req;
+
+ new_req = mempool_alloc(pool, GFP_NOIO);
+ if (!new_req)
+ return NULL;
+
+ memset(new_req, 0, sizeof(struct dst_request));
+
+ dprintk("%s: req: %p, new_req: %p, bio: %p.\n",
+ __func__, req, new_req, req->bio);
+
+ RB_CLEAR_NODE(&new_req->request_entry);
+
+ if (req) {
+ new_req->bio = req->bio;
+ new_req->state = req->state;
+ new_req->node = req->node;
+ 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;
+ new_req->bio_endio = req->bio_endio;
+ new_req->priv = req->priv;
+ }
+
+ return new_req;
+}
+EXPORT_SYMBOL_GPL(dst_clone_request);
+
+void dst_free_request(struct dst_request *req)
+{
+ dprintk("%s: free req: %p, pool: %p, bio: %p, state: %p, node: %p.\n",
+ __func__, req, req->node->w->req_pool,
+ req->bio, req->state, req->node);
+ mempool_free(req, req->node->w->req_pool);
+}
+EXPORT_SYMBOL_GPL(dst_free_request);
+
+/*
+ * 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) {
+ err = 0;
+ 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, req->node->w->req_pool);
+ 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);
+ locked = 0;
+ if (err) {
+ printk(KERN_NOTICE "%s: congestion [%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 0;
+
+out_bio_endio:
+ req->bio_endio(req, err);
+out_unlock:
+ if (locked)
+ mutex_unlock(&st->request_lock);
+ locked = 0;
+
+ if (err) {
+ err = kst_error(st, err);
+ if (!err)
+ goto alloc_new_req;
+ }
+
+ if (err) {
+ printk("%s: error [%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);
+ req->bio_endio(req, 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);
+ dprintk("%s: recovery completed.\n", __func__);
+
+ return 0;
+
+err_out_destroy:
+ sock_release(sock);
+err_out_exit:
+ dprintk("%s: revovery 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);
+
+ err = -EINVAL;
+ if (r.cmd != DST_READ && r.cmd != DST_WRITE && r.cmd != DST_REMOTE_CFG)
+ 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;
+
+ if (r.cmd == DST_REMOTE_CFG) {
+ r.sector = data_size;
+ kst_convert_header(&r);
+
+ 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_sendmsg(st->socket, &msg, &iov, 1, iov.iov_len);
+ if (err != sizeof(struct dst_remote_request)) {
+ err = -EINVAL;
+ goto err_out_exit;
+ }
+ kst_wake(st);
+ return 0;
+ }
+
+ 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 = dst_clone_request(NULL, st->node->w->req_pool);
+ if (!req)
+ goto err_out_exit;
+
+ dprintk("%s: alloc req: %p, pool: %p.\n",
+ __func__, req, st->node->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->node = st->node;
+ req->callback = &kst_data_callback;
+ req->bio_endio = &kst_bio_endio;
+
+ /*
+ * 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
+ * operationin 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:
+ dst_free_request(req);
+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, permissions = 0;
+ struct dst_secure *s;
+
+ 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;
+ }
+
+ list_for_each_entry(s, &st->request_list, sec_entry) {
+ void *sec_addr, *new_addr;
+
+ sec_addr = ((void *)&s->sec.addr) + s->sec.check_offset;
+ new_addr = ((void *)&addr) + s->sec.check_offset;
+
+ if (!memcmp(sec_addr, new_addr,
+ addr.sa_data_len - s->sec.check_offset)) {
+ permissions = s->sec.permissions;
+ break;
+ }
+ }
+
+ /*
+ * So far only reading and writing are supported.
+ * Block device does not know about anything else,
+ * but as far as I recall, there was a prognosis,
+ * that computer will never require more than 640kb of RAM.
+ */
+ if (permissions == 0) {
+ err = -EPERM;
+ goto err_out_put;
+ }
+
+ if (st->socket->ops->family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)&addr;
+ printk(KERN_INFO "%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(KERN_INFO "%s: Client: "
+ "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x:%d",
+ __func__,
+ NIP6(sin->sin6_addr), ntohs(sin->sin6_port));
+ }
+
+ dst_node_get(st->node);
+ newst = kst_state_init(st->node, permissions,
+ &kst_data_export_ops, newsock);
+ if (IS_ERR(newst)) {
+ err = PTR_ERR(newst);
+ goto err_out_put;
+ }
+
+ /*
+ * Negative return value means error, positive - stop this state
+ * processing. Zero allows to check state for pending requests.
+ * Listening socket contains security objects in request list,
+ * since it does not have any requests.
+ */
+ return 1;
+
+err_out_put:
+ sock_release(newsock);
+err_out_exit:
+ return 1;
+}
+
+static int kst_listen_init(struct kst_state *st, void *data)
+{
+ int err = -ENOMEM, i;
+ struct dst_le_template *tmp = data;
+ struct dst_secure *s;
+
+ for (i=0; i<tmp->le->secure_attr_num; ++i) {
+ s = kmalloc(sizeof(struct dst_secure), GFP_KERNEL);
+ if (!s)
+ goto err_out_exit;
+
+ memcpy(&s->sec, tmp->data, sizeof(struct dst_secure_user));
+
+ list_add_tail(&s->sec_entry, &st->request_list);
+ tmp->data += sizeof(struct dst_secure_user);
+
+ if (s->sec.addr.sa_family == AF_INET) {
+ struct sockaddr_in *sin =
+ (struct sockaddr_in *)&s->sec.addr;
+ printk(KERN_INFO "%s: Client: %u.%u.%u.%u:%d, "
+ "permissions: %x.\n",
+ __func__, NIPQUAD(sin->sin_addr.s_addr),
+ ntohs(sin->sin_port), s->sec.permissions);
+ } else if (s->sec.addr.sa_family == AF_INET6) {
+ struct sockaddr_in6 *sin =
+ (struct sockaddr_in6 *)&s->sec.addr;
+ printk(KERN_INFO "%s: Client: "
+ "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x:%d, "
+ "permissions: %x.\n",
+ __func__, NIP6(sin->sin6_addr),
+ ntohs(sin->sin6_port), s->sec.permissions);
+ }
+ }
+
+ err = kst_sock_create(st, &tmp->le->rctl.addr, tmp->le->rctl.type,
+ tmp->le->rctl.proto, tmp->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:
+ kst_listen_flush(st);
+ 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_listen_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 dst_node *node,
+ struct dst_le_template *tmp)
+{
+ return kst_state_init(node, DST_PERM_READ | DST_PERM_WRITE,
+ &kst_listen_ops, tmp);
+}
+
+struct kst_state *kst_data_state_init(struct dst_node *node,
+ struct socket *newsock)
+{
+ return kst_state_init(node, DST_PERM_READ | DST_PERM_WRITE,
+ &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/connector.h b/include/linux/connector.h
index 10eb56b..9e67d58 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -36,9 +36,11 @@
#define CN_VAL_CIFS 0x1
#define CN_W1_IDX 0x3 /* w1 communication */
#define CN_W1_VAL 0x1
+#define CN_DST_IDX 0x4 /* Distributed storage */
+#define CN_DST_VAL 0x1
-#define CN_NETLINK_USERS 4
+#define CN_NETLINK_USERS 5
/*
* Maximum connector's message size.
diff --git a/include/linux/dst.h b/include/linux/dst.h
new file mode 100644
index 0000000..3fd41dd
--- /dev/null
+++ b/include/linux/dst.h
@@ -0,0 +1,354 @@
+/*
+ * 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.
+ */
+
+#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, cmd;
+ __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;
+};
+
+#define DST_PERM_READ (1<<0)
+#define DST_PERM_WRITE (1<<1)
+
+/*
+ * Right now it is simple model, where each remote address
+ * is assigned to set of permissions it is allowed to perform.
+ * In real world block device does not know anything but
+ * reading and writing, so it should be more than enough.
+ */
+struct dst_secure_user
+{
+ unsigned int permissions;
+ unsigned short check_offset;
+ struct saddr addr;
+};
+
+struct dst_local_export_ctl
+{
+ __u32 backlog;
+ int secure_attr_num;
+ 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(KERN_NOTICE 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;
+ struct dst_node *node;
+
+ u32 flags;
+
+ int (*callback)(struct dst_request *dst,
+ unsigned int revents);
+ void (*bio_endio)(struct dst_request *dst,
+ int err);
+
+ void *priv;
+ atomic_t refcnt;
+
+ 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 socket *socket;
+
+ u32 flags, permissions;
+
+ 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_request *req);
+ 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
+#define DST_NODE_NOTSYNC 1
+
+struct dst_node
+{
+ struct rb_node tree_node;
+
+ struct list_head shared;
+ struct dst_node *shared_head;
+
+ struct block_device *bdev;
+ struct dst_storage *st;
+ struct kst_state *state;
+ struct kst_worker *w;
+
+ atomic_t refcnt;
+ atomic_t shared_num;
+
+ void (*cleanup)(struct dst_node *);
+
+ long flags;
+
+ u64 start, size;
+
+ void (*priv_callback)(struct dst_node *);
+ void *priv;
+
+ struct device device;
+};
+
+struct dst_le_template
+{
+ struct dst_local_export_ctl *le;
+ void *data;
+};
+
+struct dst_secure
+{
+ struct list_head sec_entry;
+ struct dst_secure_user sec;
+};
+
+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 dst_node *node,
+ struct dst_le_template *tmp);
+struct kst_state *kst_data_state_init(struct dst_node *node,
+ struct socket *newsock);
+
+void kst_wake(struct kst_state *st);
+
+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);
+
+static inline struct dst_node *dst_node_get(struct dst_node *n)
+{
+ atomic_inc(&n->refcnt);
+ return n;
+}
+
+struct dst_request *dst_clone_request(struct dst_request *req, mempool_t *pool);
+void dst_free_request(struct dst_request *req);
+
+void kst_complete_req(struct dst_request *req, int err);
+void kst_bio_endio(struct dst_request *req, int err);
+void kst_del_req(struct dst_request *req);
+int kst_enqueue_req(struct kst_state *st, struct dst_request *req);
+
+int kst_data_callback(struct dst_request *req, unsigned int revents);
+
+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);
+}
+
+/*
+ * Checks state's permissions.
+ * Returns -EPERM if check failed.
+ */
+static inline int kst_check_permissions(struct kst_state *st, struct bio *bio)
+{
+ if ((bio_rw(bio) == WRITE) && !(st->permissions & DST_PERM_WRITE))
+ return -EPERM;
+
+ return 0;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __DST_H */
--
Evgeniy Polyakov
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