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Subject[resend take 3 1/4] DST core files.
Date
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>

diff --git a/drivers/block/dst/dcore.c b/drivers/block/dst/dcore.c
new file mode 100644
index 0000000..fea201b
--- /dev/null
+++ b/drivers/block/dst/dcore.c
@@ -0,0 +1,972 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
+ * 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/blkdev.h>
+#include <linux/bio.h>
+#include <linux/buffer_head.h>
+#include <linux/connector.h>
+#include <linux/dst.h>
+#include <linux/device.h>
+#include <linux/jhash.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/socket.h>
+
+#include <linux/in.h>
+#include <linux/in6.h>
+
+#include <net/sock.h>
+
+static int dst_major;
+
+static DEFINE_MUTEX(dst_hash_lock);
+static struct list_head *dst_hashtable;
+static unsigned int dst_hashtable_size = 128;
+module_param(dst_hashtable_size, uint, 0644);
+
+static char dst_name[] = "Sik tee or kunem kez";
+
+static DEFINE_IDR(dst_index_idr);
+static struct cb_id cn_dst_id = { CN_DST_IDX, CN_DST_VAL };
+
+/*
+ * DST sysfs tree for device called 'storage':
+ *
+ * /sys/bus/dst/devices/storage/
+ * /sys/bus/dst/devices/storage/type : 192.168.4.80:1025
+ * /sys/bus/dst/devices/storage/size : 800
+ * /sys/bus/dst/devices/storage/name : storage
+ */
+
+static int dst_dev_match(struct device *dev, struct device_driver *drv)
+{
+ return 1;
+}
+
+static struct bus_type dst_dev_bus_type = {
+ .name = "dst",
+ .match = &dst_dev_match,
+};
+
+static void dst_node_release(struct device *dev)
+{
+ struct dst_info *info = container_of(dev, struct dst_info, device);
+
+ kfree(info);
+}
+
+static struct device dst_node_dev = {
+ .bus = &dst_dev_bus_type,
+ .release = &dst_node_release
+};
+
+/*
+ * Setting size of the node after it was changed.
+ */
+static void dst_node_set_size(struct dst_node *n)
+{
+ struct block_device *bdev;
+
+ set_capacity(n->disk, n->size >> 9);
+
+ bdev = bdget_disk(n->disk, 0);
+ if (bdev) {
+ mutex_lock(&bdev->bd_inode->i_mutex);
+ i_size_write(bdev->bd_inode, n->size);
+ mutex_unlock(&bdev->bd_inode->i_mutex);
+ bdput(bdev);
+ }
+}
+
+/*
+ * Distributed storage request processing function.
+ */
+static int dst_request(struct request_queue *q, struct bio *bio)
+{
+ struct dst_node *n = q->queuedata;
+
+ bio_get(bio);
+
+ return dst_process_bio(n, bio);
+}
+
+/*
+ * Open/close callbacks for appropriate block device.
+ */
+static int dst_bdev_open(struct inode *inode, struct file *filp)
+{
+ struct dst_node *n = inode->i_bdev->bd_disk->private_data;
+
+ dst_node_get(n);
+ return 0;
+}
+
+static int dst_bdev_release(struct inode *inode, struct file *filp)
+{
+ struct dst_node *n = inode->i_bdev->bd_disk->private_data;
+
+ dst_node_put(n);
+ return 0;
+}
+
+static struct block_device_operations dst_blk_ops = {
+ .open = dst_bdev_open,
+ .release = dst_bdev_release,
+ .owner = THIS_MODULE,
+};
+
+/*
+ * Block layer binding - disk is created when array is fully configured
+ * by userspace request.
+ */
+static int dst_node_create_disk(struct dst_node *n)
+{
+ int err = -ENOMEM;
+ u32 index = 0;
+
+ n->queue = blk_alloc_queue(GFP_KERNEL);
+ if (!n->queue)
+ goto err_out_exit;
+
+ n->queue->queuedata = n;
+ blk_queue_make_request(n->queue, dst_request);
+ blk_queue_max_phys_segments(n->queue, n->max_pages);
+ blk_queue_max_hw_segments(n->queue, n->max_pages);
+
+ err = -ENOMEM;
+ n->disk = alloc_disk(1);
+ if (!n->disk)
+ goto err_out_free_queue;
+
+ if (!(n->state->permissions & DST_PERM_WRITE)) {
+ printk(KERN_INFO "DST node %s attached read-only.\n", n->name);
+ set_disk_ro(n->disk, 1);
+ }
+
+ if (!idr_pre_get(&dst_index_idr, GFP_KERNEL))
+ goto err_out_put;
+
+ mutex_lock(&dst_hash_lock);
+ err = idr_get_new(&dst_index_idr, NULL, &index);
+ mutex_unlock(&dst_hash_lock);
+ if (err)
+ goto err_out_put;
+
+ n->disk->major = dst_major;
+ n->disk->first_minor = index;
+ n->disk->fops = &dst_blk_ops;
+ n->disk->queue = n->queue;
+ n->disk->private_data = n;
+ snprintf(n->disk->disk_name, sizeof(n->disk->disk_name), "dst-%s", n->name);
+
+ return 0;
+
+err_out_put:
+ put_disk(n->disk);
+err_out_free_queue:
+ blk_cleanup_queue(n->queue);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Sysfs machinery: show device's size.
+ */
+static ssize_t dst_show_size(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_info *info = container_of(dev, struct dst_info, device);
+
+ return sprintf(buf, "%llu\n", info->size);
+}
+
+/*
+ * Show local exported device.
+ */
+static ssize_t dst_show_local(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dst_info *info = container_of(dev, struct dst_info, device);
+
+ return sprintf(buf, "%s\n", info->local);
+}
+
+/*
+ * 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_info *info = container_of(dev, struct dst_info, device);
+ int family = info->net.addr.sa_family;
+
+ if (family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)&info->net.addr;
+ return sprintf(buf, "%u.%u.%u.%u:%d\n",
+ NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port));
+ } else if (family == AF_INET6) {
+ struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&info->net.addr;
+ return sprintf(buf,
+ "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x:%d\n",
+ NIP6(sin->sin6_addr), ntohs(sin->sin6_port));
+ } else {
+ int i, sz = PAGE_SIZE - 2; /* 0 symbol and '\n' below */
+ int size, addrlen = info->net.addr.sa_data_len;
+ unsigned char *a = (unsigned char *)&info->net.addr.sa_data;
+ char *buf_orig = buf;
+
+ size = snprintf(buf, sz, "family: %d, addrlen: %u, addr: ",
+ family, addrlen);
+ sz -= size;
+ buf += size;
+
+ for (i=0; i<addrlen; ++i) {
+ if (sz < 3)
+ break;
+
+ size = snprintf(buf, sz, "%02x ", a[i]);
+ sz -= size;
+ buf += size;
+ }
+ buf += sprintf(buf, "\n");
+
+ return buf - buf_orig;
+ }
+ return 0;
+}
+
+static struct device_attribute dst_node_attrs[] = {
+ __ATTR(size, 0444, dst_show_size, NULL),
+ __ATTR(type, 0444, dst_show_type, NULL),
+ __ATTR(local, 0444, dst_show_local, NULL),
+};
+
+static int dst_create_node_attributes(struct dst_node *n)
+{
+ int err, i;
+
+ for (i=0; i<ARRAY_SIZE(dst_node_attrs); ++i) {
+ err = device_create_file(&n->info->device,
+ &dst_node_attrs[i]);
+ if (err)
+ goto err_out_remove_all;
+ }
+ return 0;
+
+err_out_remove_all:
+ while (--i >= 0)
+ device_remove_file(&n->info->device,
+ &dst_node_attrs[i]);
+
+ return err;
+}
+
+static void dst_remove_node_attributes(struct dst_node *n)
+{
+ int i;
+
+ for (i=0; i<ARRAY_SIZE(dst_node_attrs); ++i)
+ device_remove_file(&n->info->device,
+ &dst_node_attrs[i]);
+}
+
+/*
+ * Sysfs cleanup and initialization.
+ * Shows number of useful parameters.
+ */
+static void dst_node_sysfs_exit(struct dst_node *n)
+{
+ if (n->info) {
+ dst_remove_node_attributes(n);
+ device_unregister(&n->info->device);
+ n->info = NULL;
+ }
+}
+
+static int dst_node_sysfs_init(struct dst_node *n)
+{
+ int err;
+
+ n->info = kzalloc(sizeof(struct dst_info), GFP_KERNEL);
+ if (!n->info)
+ return -ENOMEM;
+
+ memcpy(&n->info->device, &dst_node_dev, sizeof(struct device));
+ n->info->size = n->size;
+
+ snprintf(n->info->device.bus_id, sizeof(n->info->device.bus_id), "dst-%s", n->name);
+ err = device_register(&n->info->device);
+ if (err) {
+ dprintk(KERN_ERR "Failed to register node '%s', err: %d.\n",
+ n->name, err);
+ goto err_out_exit;
+ }
+
+ dst_create_node_attributes(n);
+
+ return 0;
+
+err_out_exit:
+ kfree(n->info);
+ n->info = NULL;
+ return err;
+}
+
+/*
+ * DST node hash tables machinery.
+ */
+static inline unsigned int dst_hash(char *str, unsigned int size)
+{
+ return (jhash(str, size, 0) % dst_hashtable_size);
+}
+
+static void dst_node_remove(struct dst_node *n)
+{
+ mutex_lock(&dst_hash_lock);
+ list_del_init(&n->node_entry);
+ mutex_unlock(&dst_hash_lock);
+}
+
+static void dst_node_add(struct dst_node *n)
+{
+ unsigned hash = dst_hash(n->name, sizeof(n->name));
+
+ mutex_lock(&dst_hash_lock);
+ list_add_tail(&n->node_entry, &dst_hashtable[hash]);
+ mutex_unlock(&dst_hash_lock);
+}
+
+/*
+ * Cleaning node when it is about to be freed.
+ * There are still users of the socket though,
+ * so connection cleanup should be protected.
+ */
+static void dst_node_cleanup(struct dst_node *n)
+{
+ struct dst_state *st = n->state;
+
+ if (!st)
+ return;
+
+ if (n->queue) {
+ blk_cleanup_queue(n->queue);
+
+ mutex_lock(&dst_hash_lock);
+ idr_remove(&dst_index_idr, n->disk->first_minor);
+ mutex_unlock(&dst_hash_lock);
+
+ put_disk(n->disk);
+ }
+
+ if (n->bdev) {
+ sync_blockdev(n->bdev);
+ blkdev_put(n->bdev);
+ }
+
+ dst_state_lock(st);
+ st->need_exit = 1;
+ dst_state_exit_connected(st);
+ dst_state_unlock(st);
+
+ wake_up(&st->thread_wait);
+
+ dst_state_put(st);
+ n->state = NULL;
+}
+
+/*
+ * Free security attributes attached to given node.
+ */
+static void dst_security_exit(struct dst_node *n)
+{
+ struct dst_secure *s, *tmp;
+
+ list_for_each_entry_safe(s, tmp, &n->security_list, sec_entry) {
+ list_del(&s->sec_entry);
+ kfree(s);
+ }
+}
+
+/*
+ * Free node when there are no more users.
+ * Actually node has to be freed on behalf od userspace process,
+ * since there are number of threads, which are embedded in the
+ * node, so they can not exit and free node from there, that is
+ * why there is a wakeup if reference counter is not equal to zero.
+ */
+void dst_node_put(struct dst_node *n)
+{
+ if (unlikely(!n))
+ return;
+
+ dprintk("%s: n: %p, refcnt: %d.\n",
+ __func__, n, atomic_read(&n->refcnt));
+
+ if (atomic_dec_and_test(&n->refcnt)) {
+ dst_node_remove(n);
+ n->trans_scan_timeout = 0;
+ dst_node_cleanup(n);
+ thread_pool_destroy(n->pool);
+ dst_node_sysfs_exit(n);
+ dst_node_crypto_exit(n);
+ dst_security_exit(n);
+ dst_node_trans_exit(n);
+
+ kfree(n);
+
+ dprintk("%s: freed n: %p.\n", __func__, n);
+ } else {
+ wake_up(&n->wait);
+ }
+}
+
+/*
+ * 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.path.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_put(&nd.path);
+ return err;
+}
+
+/*
+ * Setting up export device: lookup by the name, get its size
+ * and setup listening socket, which will accept clients, which
+ * will submit IO for given storage.
+ */
+static int dst_setup_export(struct dst_node *n, struct dst_ctl *ctl,
+ struct dst_export_ctl *le)
+{
+ int err;
+ dev_t dev = 0; /* gcc likes to scream here */
+
+ snprintf(n->info->local, sizeof(n->info->local), "%s", le->device);
+
+ err = dst_lookup_device(le->device, &dev);
+ if (err)
+ return err;
+
+ n->bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+ if (!n->bdev)
+ return -ENODEV;
+
+ if (n->size != 0)
+ n->size = min_t(loff_t, n->bdev->bd_inode->i_size, n->size);
+ else
+ n->size = n->bdev->bd_inode->i_size;
+
+ n->info->size = n->size;
+ err = dst_node_init_listened(n, le);
+ if (err)
+ goto err_out_cleanup;
+
+ return 0;
+
+err_out_cleanup:
+ blkdev_put(n->bdev);
+ n->bdev = NULL;
+
+ return err;
+}
+
+/* Empty thread pool callbacks for the network processing threads. */
+static inline void *dst_thread_network_init(void *data)
+{
+ dprintk("%s: data: %p.\n", __func__, data);
+ return data;
+}
+
+static inline void dst_thread_network_cleanup(void *data)
+{
+ dprintk("%s: data: %p.\n", __func__, data);
+}
+
+/*
+ * Allocate DST node and initialize some of its parameters.
+ */
+static struct dst_node *dst_alloc_node(struct dst_ctl *ctl,
+ int (*start)(struct dst_node *),
+ int num)
+{
+ struct dst_node *n;
+ int err;
+
+ n = kzalloc(sizeof(struct dst_node), GFP_KERNEL);
+ if (!n)
+ return NULL;
+
+ INIT_LIST_HEAD(&n->node_entry);
+
+ INIT_LIST_HEAD(&n->security_list);
+ mutex_init(&n->security_lock);
+
+ init_waitqueue_head(&n->wait);
+
+ n->trans_scan_timeout = msecs_to_jiffies(ctl->trans_scan_timeout);
+ if (!n->trans_scan_timeout)
+ n->trans_scan_timeout = HZ;
+
+ n->trans_max_retries = ctl->trans_max_retries;
+ if (!n->trans_max_retries)
+ n->trans_max_retries = 10;
+
+ /*
+ * Pretty much arbitrary default numbers.
+ * 32 matches maximum number of pages in bio originated from ext3 (31).
+ */
+ n->max_pages = ctl->max_pages;
+ if (!n->max_pages)
+ n->max_pages = 32;
+
+ if (n->max_pages > 1024)
+ n->max_pages = 1024;
+
+ n->start = start;
+ n->size = ctl->size;
+
+ atomic_set(&n->refcnt, 1);
+ atomic_long_set(&n->gen, 0);
+ snprintf(n->name, sizeof(n->name), "%s", ctl->name);
+
+ err = dst_node_sysfs_init(n);
+ if (err)
+ goto err_out_free;
+
+ n->pool = thread_pool_create(num, n->name, dst_thread_network_init,
+ dst_thread_network_cleanup, n);
+ if (IS_ERR(n->pool)) {
+ err = PTR_ERR(n->pool);
+ goto err_out_sysfs_exit;
+ }
+
+ dprintk("%s: n: %p, name: %s.\n", __func__, n, n->name);
+
+ return n;
+
+err_out_sysfs_exit:
+ dst_node_sysfs_exit(n);
+err_out_free:
+ kfree(n);
+ return NULL;
+}
+
+/*
+ * Starting a node, connected to the remote server:
+ * register block device and initialize transaction mechanism.
+ * In revers order though.
+ *
+ * It will autonegotiate some parameters with the remote node
+ * and update local if needed.
+ *
+ * Transaction initialization should be the last thing before
+ * starting the node, since transaction should include not only
+ * block IO, but also crypto related data (if any), which are
+ * initialized separately.
+ */
+static int dst_start_remote(struct dst_node *n)
+{
+ int err;
+
+ err = dst_node_trans_init(n, sizeof(struct dst_trans));
+ if (err)
+ return err;
+
+ err = dst_node_create_disk(n);
+ if (err)
+ return err;
+
+ dst_node_set_size(n);
+ add_disk(n->disk);
+
+ dprintk("DST: started remote node '%s', minor: %d.\n", n->name, n->disk->first_minor);
+
+ return 0;
+}
+
+/*
+ * Adding remote node and initialize connection.
+ */
+static int dst_add_remote(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ int err;
+ struct dst_network_ctl *rctl = data;
+
+ if (n)
+ return -EEXIST;
+
+ if (size != sizeof(struct dst_network_ctl))
+ return -EINVAL;
+
+ n = dst_alloc_node(ctl, dst_start_remote, 1);
+ if (!n)
+ return -ENOMEM;
+
+ memcpy(&n->info->net, rctl, sizeof(struct dst_network_ctl));
+ err = dst_node_init_connected(n, rctl);
+ if (err)
+ goto err_out_free;
+
+ dst_node_add(n);
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ return err;
+}
+
+/*
+ * Adding export node: initializing block device and listening socket.
+ */
+static int dst_add_export(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ int err;
+ struct dst_export_ctl *le = data;
+
+ if (n)
+ return -EEXIST;
+
+ if (size != sizeof(struct dst_export_ctl))
+ return -EINVAL;
+
+ n = dst_alloc_node(ctl, dst_start_export, 2);
+ if (!n)
+ return -EINVAL;
+
+ err = dst_setup_export(n, ctl, le);
+ if (err)
+ goto err_out_free;
+
+ dst_node_add(n);
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ return err;
+}
+
+static int dst_node_remove_unload(struct dst_node *n)
+{
+ printk(KERN_INFO "STOPPED name: '%s', size: %llu.\n",
+ n->name, n->size);
+
+ if (n->disk)
+ del_gendisk(n->disk);
+
+ dst_node_remove(n);
+ dst_node_sysfs_exit(n);
+
+ /*
+ * This is not a hack. Really.
+ * Node's reference counter allows to implement fine grained
+ * node freeing, but since all transactions (which hold node's
+ * reference counter) are processed in the dedicated thread,
+ * it is possible that reference will hit zero in that thread,
+ * so we will not be able to exit thread and cleanup the node.
+ *
+ * So, we remove disk, so no new activity is possible, and
+ * wait until all pending transaction are completed (either
+ * in receiving thread or by timeout in workqueue), in this
+ * case reference counter will be less or equal to 2 (once set in
+ * dst_alloc_node() and then in connector message parser;
+ * or when we force module unloading, and connector message
+ * parser does not hold a reference, in this case reference
+ * counter will be equal to 1),
+ * and subsequent dst_node_put() calls will free the node.
+ */
+ dprintk("%s: going to sleep with %d refcnt.\n", __func__, atomic_read(&n->refcnt));
+ wait_event(n->wait, atomic_read(&n->refcnt) <= 2);
+
+ dst_node_put(n);
+ return 0;
+}
+
+/*
+ * Remove node from the hash table.
+ */
+static int dst_del_node(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ if (!n)
+ return -ENODEV;
+
+ return dst_node_remove_unload(n);
+}
+
+/*
+ * Initialize crypto processing for given node.
+ */
+static int dst_crypto_init(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ struct dst_crypto_ctl *crypto = data;
+
+ if (!n)
+ return -ENODEV;
+
+ if (size != sizeof(struct dst_crypto_ctl) + crypto->hash_keysize +
+ crypto->cipher_keysize)
+ return -EINVAL;
+
+ if (n->trans_cache)
+ return -EEXIST;
+
+ return dst_node_crypto_init(n, crypto);
+}
+
+/*
+ * Security attributes for given node.
+ */
+static int dst_security_init(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ struct dst_secure *s;
+
+ if (!n)
+ return -ENODEV;
+
+ if (size != sizeof(struct dst_secure_user))
+ return -EINVAL;
+
+ s = kmalloc(sizeof(struct dst_secure), GFP_KERNEL);
+ if (!s)
+ return -ENOMEM;
+
+ memcpy(&s->sec, data, size);
+
+ mutex_lock(&n->security_lock);
+ list_add_tail(&s->sec_entry, &n->security_list);
+ mutex_unlock(&n->security_lock);
+
+ return 0;
+}
+
+/*
+ * Kill'em all!
+ */
+static int dst_start_node(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size)
+{
+ int err;
+
+ if (!n)
+ return -ENODEV;
+
+ if (n->trans_cache)
+ return 0;
+
+ err = n->start(n);
+ if (err)
+ return err;
+
+ printk(KERN_INFO "STARTED name: '%s', size: %llu.\n", n->name, n->size);
+ return 0;
+}
+
+typedef int (*dst_command_func)(struct dst_node *n, struct dst_ctl *ctl,
+ void *data, unsigned int size);
+
+/*
+ * List of userspace commands.
+ */
+static dst_command_func dst_commands[] = {
+ [DST_ADD_REMOTE] = &dst_add_remote,
+ [DST_ADD_EXPORT] = &dst_add_export,
+ [DST_DEL_NODE] = &dst_del_node,
+ [DST_CRYPTO] = &dst_crypto_init,
+ [DST_SECURITY] = &dst_security_init,
+ [DST_START] = &dst_start_node,
+};
+
+/*
+ * Configuration parser.
+ */
+static void cn_dst_callback(void *data)
+{
+ struct dst_ctl *ctl;
+ struct cn_msg *msg = data;
+ int err;
+ struct dst_ctl_ack ack;
+ struct dst_node *n = NULL, *tmp;
+ unsigned int hash;
+
+ if (msg->len < sizeof(struct dst_ctl)) {
+ err = -EBADMSG;
+ goto out;
+ }
+
+ ctl = (struct dst_ctl *)msg->data;
+
+ if (ctl->cmd >= DST_CMD_MAX) {
+ err = -EINVAL;
+ goto out;
+ }
+ hash = dst_hash(ctl->name, sizeof(ctl->name));
+
+ mutex_lock(&dst_hash_lock);
+ list_for_each_entry(tmp, &dst_hashtable[hash], node_entry) {
+ if (!memcmp(tmp->name, ctl->name, sizeof(tmp->name))) {
+ n = tmp;
+ dst_node_get(n);
+ break;
+ }
+ }
+ mutex_unlock(&dst_hash_lock);
+
+ err = dst_commands[ctl->cmd](n, ctl, msg->data + sizeof(struct dst_ctl),
+ msg->len - sizeof(struct dst_ctl));
+
+ dst_node_put(n);
+out:
+ memcpy(&ack.msg, msg, sizeof(struct cn_msg));
+
+ ack.msg.ack = msg->ack + 1;
+ ack.msg.len = sizeof(struct dst_ctl_ack) - sizeof(struct cn_msg);
+
+ ack.error = err;
+
+ cn_netlink_send(&ack.msg, 0, GFP_KERNEL);
+}
+
+/*
+ * Global initialization: sysfs, hash table, block device registration,
+ * connector and various caches.
+ */
+static int __init dst_sysfs_init(void)
+{
+ return bus_register(&dst_dev_bus_type);
+}
+
+static void dst_sysfs_exit(void)
+{
+ bus_unregister(&dst_dev_bus_type);
+}
+
+static int __init dst_hashtable_init(void)
+{
+ unsigned int i;
+
+ dst_hashtable = kcalloc(dst_hashtable_size, sizeof(struct list_head),
+ GFP_KERNEL);
+ if (!dst_hashtable)
+ return -ENOMEM;
+
+ for (i=0; i<dst_hashtable_size; ++i)
+ INIT_LIST_HEAD(&dst_hashtable[i]);
+
+ return 0;
+}
+
+static void dst_hashtable_exit(void)
+{
+ unsigned int i;
+ struct dst_node *n, *tmp;
+
+ for (i=0; i<dst_hashtable_size; ++i) {
+ list_for_each_entry_safe(n, tmp, &dst_hashtable[i], node_entry) {
+ dst_node_remove_unload(n);
+ }
+ }
+
+ kfree(dst_hashtable);
+}
+
+static int __init dst_sys_init(void)
+{
+ int err = -ENOMEM;
+
+ err = dst_hashtable_init();
+ if (err)
+ goto err_out_exit;
+
+ err = dst_export_init();
+ if (err)
+ goto err_out_hashtable_exit;
+
+ err = register_blkdev(dst_major, DST_NAME);
+ if (err < 0)
+ goto err_out_export_exit;
+ if (err)
+ dst_major = err;
+
+ err = dst_sysfs_init();
+ if (err)
+ goto err_out_unregister;
+
+ err = cn_add_callback(&cn_dst_id, "DST", cn_dst_callback);
+ if (err)
+ goto err_out_sysfs_exit;
+
+ printk(KERN_INFO "Distributed storage, '%s' release.\n", dst_name);
+
+ return 0;
+
+err_out_sysfs_exit:
+ dst_sysfs_exit();
+err_out_unregister:
+ unregister_blkdev(dst_major, DST_NAME);
+err_out_export_exit:
+ dst_export_exit();
+err_out_hashtable_exit:
+ dst_hashtable_exit();
+err_out_exit:
+ return err;
+}
+
+static void __exit dst_sys_exit(void)
+{
+ cn_del_callback(&cn_dst_id);
+ unregister_blkdev(dst_major, DST_NAME);
+ dst_hashtable_exit();
+ dst_sysfs_exit();
+ dst_export_exit();
+}
+
+module_init(dst_sys_init);
+module_exit(dst_sys_exit);
+
+MODULE_DESCRIPTION("Distributed storage");
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/block/dst/trans.c b/drivers/block/dst/trans.c
new file mode 100644
index 0000000..557d372
--- /dev/null
+++ b/drivers/block/dst/trans.c
@@ -0,0 +1,335 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
+ * 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/bio.h>
+#include <linux/dst.h>
+#include <linux/slab.h>
+#include <linux/mempool.h>
+
+/*
+ * Transaction memory pool size.
+ */
+static int dst_mempool_num = 32;
+module_param(dst_mempool_num, int, 0644);
+
+/*
+ * Transaction tree management.
+ */
+static inline int dst_trans_cmp(dst_gen_t gen, dst_gen_t new)
+{
+ if (gen < new)
+ return 1;
+ if (gen > new)
+ return -1;
+ return 0;
+}
+
+struct dst_trans *dst_trans_search(struct dst_node *node, dst_gen_t gen)
+{
+ struct rb_root *root = &node->trans_root;
+ struct rb_node *n = root->rb_node;
+ struct dst_trans *t, *ret = NULL;
+ int cmp;
+
+ while (n) {
+ t = rb_entry(n, struct dst_trans, trans_entry);
+
+ cmp = dst_trans_cmp(t->gen, gen);
+ if (cmp < 0)
+ n = n->rb_left;
+ else if (cmp > 0)
+ n = n->rb_right;
+ else {
+ ret = t;
+ break;
+ }
+ }
+
+ dprintk("%s: %s transaction: id: %llu.\n", __func__,
+ (ret)?"found":"not found", gen);
+
+ return ret;
+}
+
+static int dst_trans_insert(struct dst_trans *new)
+{
+ struct rb_root *root = &new->n->trans_root;
+ struct rb_node **n = &root->rb_node, *parent = NULL;
+ struct dst_trans *ret = NULL, *t;
+ int cmp;
+
+ while (*n) {
+ parent = *n;
+
+ t = rb_entry(parent, struct dst_trans, trans_entry);
+
+ cmp = dst_trans_cmp(t->gen, new->gen);
+ if (cmp < 0)
+ n = &parent->rb_left;
+ else if (cmp > 0)
+ n = &parent->rb_right;
+ else {
+ ret = t;
+ break;
+ }
+ }
+
+ new->send_time = jiffies;
+ if (ret) {
+ printk("%s: exist: old: gen: %llu, bio: %llu/%u, send_time: %lu, "
+ "new: gen: %llu, bio: %llu/%u, send_time: %lu.\n",
+ __func__,
+ ret->gen, (u64)ret->bio->bi_sector,
+ ret->bio->bi_size, ret->send_time,
+ new->gen, (u64)new->bio->bi_sector,
+ new->bio->bi_size, new->send_time);
+ return -EEXIST;
+ }
+
+ rb_link_node(&new->trans_entry, parent, n);
+ rb_insert_color(&new->trans_entry, root);
+
+ dprintk("%s: inserted: gen: %llu, bio: %llu/%u, send_time: %lu.\n",
+ __func__, new->gen, (u64)new->bio->bi_sector,
+ new->bio->bi_size, new->send_time);
+
+ return 0;
+}
+
+int dst_trans_remove_nolock(struct dst_trans *t)
+{
+ struct dst_node *n = t->n;
+
+ if (t->trans_entry.rb_parent_color) {
+ rb_erase(&t->trans_entry, &n->trans_root);
+ t->trans_entry.rb_parent_color = 0;
+ }
+ return 0;
+}
+
+int dst_trans_remove(struct dst_trans *t)
+{
+ int ret;
+ struct dst_node *n = t->n;
+
+ mutex_lock(&n->trans_lock);
+ ret = dst_trans_remove_nolock(t);
+ mutex_unlock(&n->trans_lock);
+
+ return ret;
+}
+
+/*
+ * When transaction is completed and there are no more users,
+ * we complete appriate block IO request with given error status.
+ */
+void dst_trans_put(struct dst_trans *t)
+{
+ if (atomic_dec_and_test(&t->refcnt)) {
+ struct bio *bio = t->bio;
+
+ dprintk("%s: completed t: %p, gen: %llu, bio: %p.\n",
+ __func__, t, t->gen, bio);
+
+ bio_endio(bio, t->error);
+ bio_put(bio);
+
+ dst_node_put(t->n);
+ mempool_free(t, t->n->trans_pool);
+ }
+}
+
+/*
+ * Process given block IO request: allocate transaction, insert it into the tree
+ * and send/schedule crypto processing.
+ */
+int dst_process_bio(struct dst_node *n, struct bio *bio)
+{
+ struct dst_trans *t;
+ int err = -ENOMEM;
+
+ t = mempool_alloc(n->trans_pool, GFP_NOFS);
+ if (!t)
+ goto err_out_exit;
+
+ t->n = dst_node_get(n);
+ t->bio = bio;
+ t->error = 0;
+ t->retries = 0;
+ atomic_set(&t->refcnt, 1);
+ t->gen = atomic_long_inc_return(&n->gen);
+
+ t->enc = bio_data_dir(bio);
+ dst_bio_to_cmd(bio, &t->cmd, DST_IO, t->gen);
+
+ mutex_lock(&n->trans_lock);
+ err = dst_trans_insert(t);
+ mutex_unlock(&n->trans_lock);
+ if (err)
+ goto err_out_free;
+
+ dprintk("%s: gen: %llu, bio: %llu/%u, dir/enc: %d, need_crypto: %d.\n",
+ __func__, t->gen, (u64)bio->bi_sector,
+ bio->bi_size, t->enc, dst_need_crypto(n));
+
+ if (dst_need_crypto(n) && t->enc)
+ dst_trans_crypto(t);
+ else
+ dst_trans_send(t);
+
+ return 0;
+
+err_out_free:
+ dst_node_put(n);
+ mempool_free(t, n->trans_pool);
+err_out_exit:
+ bio_endio(bio, err);
+ bio_put(bio);
+ return err;
+}
+
+/*
+ * Scan for timeout/stale transactions.
+ * Each transaction is being resent multiple times before error completion.
+ */
+static void dst_trans_scan(struct work_struct *work)
+{
+ struct dst_node *n = container_of(work, struct dst_node, trans_work.work);
+ struct rb_node *rb_node;
+ struct dst_trans *t;
+ unsigned long timeout = n->trans_scan_timeout;
+ int num = 10 * n->trans_max_retries;
+
+ mutex_lock(&n->trans_lock);
+
+ for (rb_node = rb_first(&n->trans_root); rb_node; ) {
+ t = rb_entry(rb_node, struct dst_trans, trans_entry);
+
+ if (timeout && time_after(t->send_time + timeout, jiffies)
+ && t->retries == 0)
+ break;
+#if 0
+ dprintk("%s: t: %p, gen: %llu, n: %s, retries: %u, max: %u.\n",
+ __func__, t, t->gen, n->name,
+ t->retries, n->trans_max_retries);
+#endif
+ if (--num == 0)
+ break;
+
+ dst_trans_get(t);
+
+ rb_node = rb_next(rb_node);
+
+ if (timeout && (++t->retries < n->trans_max_retries)) {
+ dst_trans_send(t);
+ } else {
+ t->error = -ETIMEDOUT;
+ dst_trans_remove_nolock(t);
+ dst_trans_put(t);
+ }
+
+ dst_trans_put(t);
+ }
+
+ mutex_unlock(&n->trans_lock);
+
+ /*
+ * If no timeout specified then system is in the middle of exiting process,
+ * so no need to reschedule scanning process again.
+ */
+ if (timeout) {
+ if (!num)
+ timeout = HZ;
+ schedule_delayed_work(&n->trans_work, timeout);
+ }
+}
+
+/*
+ * Flush all transactions and mark them as timed out.
+ * Destroy transaction pools.
+ */
+void dst_node_trans_exit(struct dst_node *n)
+{
+ struct dst_trans *t;
+ struct rb_node *rb_node;
+
+ if (!n->trans_cache)
+ return;
+
+ dprintk("%s: n: %p, cancelling the work.\n", __func__, n);
+ cancel_delayed_work_sync(&n->trans_work);
+ flush_scheduled_work();
+ dprintk("%s: n: %p, work has been cancelled.\n", __func__, n);
+
+ for (rb_node = rb_first(&n->trans_root); rb_node; ) {
+ t = rb_entry(rb_node, struct dst_trans, trans_entry);
+
+ dprintk("%s: t: %p, gen: %llu, n: %s.\n",
+ __func__, t, t->gen, n->name);
+
+ rb_node = rb_next(rb_node);
+
+ t->error = -ETIMEDOUT;
+ dst_trans_remove_nolock(t);
+ dst_trans_put(t);
+ }
+
+ mempool_destroy(n->trans_pool);
+ kmem_cache_destroy(n->trans_cache);
+}
+
+/*
+ * Initialize transaction storage for given node.
+ * Transaction stores not only control information,
+ * but also network command and crypto data (if needed)
+ * to reduce number of allocations. Thus transaction size
+ * differs from node to node.
+ */
+int dst_node_trans_init(struct dst_node *n, unsigned int size)
+{
+ /*
+ * We need this, since node with given name can be dropped from the
+ * hash table, but be still alive, so subsequent creation of the node
+ * with the same name may collide with existing cache name.
+ */
+
+ snprintf(n->cache_name, sizeof(n->cache_name), "%s-%p", n->name, n);
+
+ n->trans_cache = kmem_cache_create(n->cache_name,
+ size + n->crypto.crypto_attached_size,
+ 0, 0, NULL);
+ if (!n->trans_cache)
+ goto err_out_exit;
+
+ n->trans_pool = mempool_create_slab_pool(dst_mempool_num, n->trans_cache);
+ if (!n->trans_pool)
+ goto err_out_cache_destroy;
+
+ mutex_init(&n->trans_lock);
+ n->trans_root = RB_ROOT;
+
+ INIT_DELAYED_WORK(&n->trans_work, dst_trans_scan);
+ schedule_delayed_work(&n->trans_work, n->trans_scan_timeout);
+
+ dprintk("%s: n: %p, size: %u, crypto: %u.\n",
+ __func__, n, size, n->crypto.crypto_attached_size);
+
+ return 0;
+
+err_out_cache_destroy:
+ kmem_cache_destroy(n->trans_cache);
+err_out_exit:
+ return -ENOMEM;
+}
diff --git a/include/linux/connector.h b/include/linux/connector.h
index 5c7f946..1980f08 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -39,8 +39,10 @@
#define CN_IDX_V86D 0x4
#define CN_VAL_V86D_UVESAFB 0x1
#define CN_IDX_BB 0x5 /* BlackBoard, from the TSP GPL sampling framework */
+#define CN_DST_IDX 0x6
+#define CN_DST_VAL 0x1

-#define CN_NETLINK_USERS 6
+#define CN_NETLINK_USERS 7

/*
* Maximum connector's message size.
diff --git a/include/linux/dst.h b/include/linux/dst.h
new file mode 100644
index 0000000..83b2ba0
--- /dev/null
+++ b/include/linux/dst.h
@@ -0,0 +1,587 @@
+/*
+ * 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>
+#include <linux/connector.h>
+
+#define DST_NAMELEN 32
+#define DST_NAME "dst"
+
+enum {
+ /* Remove node with given id from storage */
+ DST_DEL_NODE = 0,
+ /* Add remote node with given id to the storage */
+ DST_ADD_REMOTE,
+ /* Add local node with given id to the storage to be exported and used by remote peers */
+ DST_ADD_EXPORT,
+ /* Crypto initialization command (hash/cipher used to protect the connection) */
+ DST_CRYPTO,
+ /* Security attributes for given connection (permissions for example) */
+ DST_SECURITY,
+ /* Register given node in the block layer subsystem */
+ DST_START,
+ DST_CMD_MAX
+};
+
+struct dst_ctl
+{
+ /* Storage name */
+ char name[DST_NAMELEN];
+ /* Command flags */
+ __u32 flags;
+ /* Command itself (see above) */
+ __u32 cmd;
+ /* Maximum number of pages per single request in this device */
+ __u32 max_pages;
+ /* Stale/error transaction scanning timeout in milliseconds */
+ __u32 trans_scan_timeout;
+ /* Maximum number of retry sends before completing transaction as broken */
+ __u32 trans_max_retries;
+ /* Storage size */
+ __u64 size;
+};
+
+/* Reply command carries completion status */
+struct dst_ctl_ack
+{
+ struct cn_msg msg;
+ int error;
+ int unused[3];
+};
+
+/*
+ * Unfortunaltely socket address structure is not exported to userspace
+ * and is redefined there.
+ */
+#define SADDR_MAX_DATA 128
+
+struct saddr {
+ /* address family, AF_xxx */
+ unsigned short sa_family;
+ /* 14 bytes of protocol address */
+ char sa_data[SADDR_MAX_DATA];
+ /* Number of bytes used in sa_data */
+ unsigned short sa_data_len;
+};
+
+/* Address structure */
+struct dst_network_ctl
+{
+ /* Socket type: datagram, stream...*/
+ unsigned int type;
+ /* Let me guess, is it a Jupiter diameter? */
+ unsigned int proto;
+ /* Peer's address */
+ struct saddr addr;
+};
+
+struct dst_crypto_ctl
+{
+ /* Cipher and hash names */
+ char cipher_algo[DST_NAMELEN];
+ char hash_algo[DST_NAMELEN];
+
+ /* Key sizes. Can be zero for digest for example */
+ unsigned int cipher_keysize, hash_keysize;
+ /* Alignment. Calculated by the DST itself. */
+ unsigned int crypto_attached_size;
+ /* Number of threads to perform crypto operations */
+ int thread_num;
+};
+
+/* Export security attributes have this bits checked in when client connects */
+#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;
+ struct saddr addr;
+};
+
+/*
+ * Export control command: device to export and network address to accept
+ * clients to work with given device
+ */
+struct dst_export_ctl
+{
+ char device[DST_NAMELEN];
+ struct dst_network_ctl ctl;
+};
+
+enum {
+ DST_CFG = 1, /* Request remote configuration */
+ DST_IO, /* IO command */
+ DST_IO_RESPONSE, /* IO response */
+ DST_PING, /* Keepalive message */
+ DST_NCMD_MAX,
+};
+
+struct dst_cmd
+{
+ /* Network command itself, see above */
+ __u32 cmd;
+ /*
+ * Size of the attached data
+ * (in most cases, for READ command it means how many bytes were requested)
+ */
+ __u32 size;
+ /* Crypto size: number of attached bytes with digest/hmac */
+ __u32 csize;
+ /* Here we can carry secret data */
+ __u32 reserved;
+ /* Read/write bits, see how they are encoded in bio structure */
+ __u64 rw;
+ /* BIO flags */
+ __u64 flags;
+ /* Unique command id (like transaction ID) */
+ __u64 id;
+ /* Sector to start IO from */
+ __u64 sector;
+ /* Hash data is placed after this header */
+ __u8 hash[0];
+};
+
+/*
+ * Convert command to/from network byte order.
+ * We do not use hton*() functions, since there is
+ * no 64-bit implementation.
+ */
+static inline void dst_convert_cmd(struct dst_cmd *c)
+{
+ c->cmd = __cpu_to_be32(c->cmd);
+ c->csize = __cpu_to_be32(c->csize);
+ c->size = __cpu_to_be32(c->size);
+ c->sector = __cpu_to_be64(c->sector);
+ c->id = __cpu_to_be64(c->id);
+ c->flags = __cpu_to_be64(c->flags);
+ c->rw = __cpu_to_be64(c->rw);
+}
+
+/* Transaction id */
+typedef __u64 dst_gen_t;
+
+#ifdef __KERNEL__
+
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/device.h>
+#include <linux/mempool.h>
+#include <linux/net.h>
+#include <linux/poll.h>
+#include <linux/rbtree.h>
+
+#ifdef CONFIG_DST_DEBUG
+#define dprintk(f, a...) printk(KERN_NOTICE f, ##a)
+#else
+static inline void __attribute__ ((format (printf, 1, 2)))
+ dprintk(const char *fmt, ...) {}
+#endif
+
+struct dst_node;
+
+struct dst_trans
+{
+ /* DST node we are working with */
+ struct dst_node *n;
+
+ /* Entry inside transaction tree */
+ struct rb_node trans_entry;
+
+ /* Merlin kills this transaction when this memory cell equals zero */
+ atomic_t refcnt;
+
+ /* How this transaction should be processed by crypto engine */
+ short enc;
+ /* How many times this transaction was resent */
+ short retries;
+ /* Completion status */
+ int error;
+
+ /* When did we send it to the remote peer */
+ long send_time;
+
+ /* My name is...
+ * Well, computers does not speak, they have unique id instead */
+ dst_gen_t gen;
+
+ /* Block IO we are working with */
+ struct bio *bio;
+
+ /* Network command for above block IO request */
+ struct dst_cmd cmd;
+};
+
+struct dst_crypto_engine
+{
+ /* What should we do with all block requests */
+ struct crypto_hash *hash;
+ struct crypto_ablkcipher *cipher;
+
+ /* Pool of pages used to encrypt data into before sending */
+ int page_num;
+ struct page **pages;
+
+ /* What to do with current request */
+ int enc;
+ /* Who we are and where do we go */
+ struct scatterlist *src, *dst;
+
+ /* Maximum timeout waiting for encryption to be completed */
+ long timeout;
+ /* IV is a 64-bit sequential counter */
+ u64 iv;
+
+ /* Secret data */
+ void *private;
+
+ /* Cached temporary data lives here */
+ int size;
+ void *data;
+};
+
+struct dst_state
+{
+ /* The main state protection */
+ struct mutex state_lock;
+
+ /* Polling machinery for sockets */
+ wait_queue_t wait;
+ wait_queue_head_t *whead;
+ /* Most of events are being waited here */
+ wait_queue_head_t thread_wait;
+
+ /* Who owns this? */
+ struct dst_node *node;
+
+ /* Network address for this state */
+ struct dst_network_ctl ctl;
+
+ /* Permissions to work with: read-only or rw connection */
+ u32 permissions;
+
+ /* Called when we need to clean private data */
+ void (* cleanup)(struct dst_state *st);
+
+ /* Used by the server: BIO completion queues BIOs here */
+ struct list_head request_list;
+ spinlock_t request_lock;
+
+ /* Guess what? No, it is not number of planets */
+ atomic_t refcnt;
+
+ /* This flags is set when connection should be dropped */
+ int need_exit;
+
+ /*
+ * Socket to work with. Second pointer is used for
+ * lockless check if socket was changed before performing
+ * next action (like working with cached polling result)
+ */
+ struct socket *socket, *read_socket;
+
+ /* Cached preallocated data */
+ void *data;
+ unsigned int size;
+
+ /* Currently processed command */
+ struct dst_cmd cmd;
+};
+
+struct dst_info
+{
+ /* Device size */
+ u64 size;
+
+ /* Local device name for export devices */
+ char local[DST_NAMELEN];
+
+ /* Network setup */
+ struct dst_network_ctl net;
+
+ /* Sysfs bits use this */
+ struct device device;
+};
+
+struct dst_node
+{
+ struct list_head node_entry;
+
+ /* Hi, my name is stored here */
+ char name[DST_NAMELEN];
+ /* My cache name is stored here */
+ char cache_name[DST_NAMELEN];
+
+ /* Block device attached to given node.
+ * Only valid for exporting nodes */
+ struct block_device *bdev;
+ /* Network state machine for given peer */
+ struct dst_state *state;
+
+ /* Block IO machinery */
+ struct request_queue *queue;
+ struct gendisk *disk;
+
+ /* Number of threads in processing pool */
+ int thread_num;
+ /* Maximum number of pages in single IO */
+ int max_pages;
+
+ /* I'm that big in bytes */
+ loff_t size;
+
+ /* Exported to userspace node information */
+ struct dst_info *info;
+
+ /*
+ * Security attribute list.
+ * Used only by exporting node currently.
+ */
+ struct list_head security_list;
+ struct mutex security_lock;
+
+ /*
+ * When this unerflows below zero, university collapses.
+ * But this will not happen, since node will be freed,
+ * when reference counter reaches zero.
+ */
+ atomic_t refcnt;
+
+ /* How precisely should I be started? */
+ int (*start)(struct dst_node *);
+
+ /* Crypto capabilities */
+ struct dst_crypto_ctl crypto;
+ u8 *hash_key;
+ u8 *cipher_key;
+
+ /* Pool of processing thread */
+ struct thread_pool *pool;
+
+ /* Transaction IDs live here */
+ atomic_long_t gen;
+
+ /*
+ * How frequently and how many times transaction
+ * tree should be scanned to drop stale objects.
+ */
+ long trans_scan_timeout;
+ int trans_max_retries;
+
+ /* Small gnomes live here */
+ struct rb_root trans_root;
+ struct mutex trans_lock;
+
+ /*
+ * Transaction cache/memory pool.
+ * It is big enough to contain not only transaction
+ * itself, but additional crypto data (digest/hmac).
+ */
+ struct kmem_cache *trans_cache;
+ mempool_t *trans_pool;
+
+ /* This entity scans transaction tree */
+ struct delayed_work trans_work;
+
+ wait_queue_head_t wait;
+};
+
+/* Kernel representation of the security attribute */
+struct dst_secure
+{
+ struct list_head sec_entry;
+ struct dst_secure_user sec;
+};
+
+int dst_process_bio(struct dst_node *n, struct bio *bio);
+
+int dst_node_init_connected(struct dst_node *n, struct dst_network_ctl *r);
+int dst_node_init_listened(struct dst_node *n, struct dst_export_ctl *le);
+
+static inline struct dst_state *dst_state_get(struct dst_state *st)
+{
+ BUG_ON(atomic_read(&st->refcnt) == 0);
+ atomic_inc(&st->refcnt);
+ return st;
+}
+
+void dst_state_put(struct dst_state *st);
+
+struct dst_state *dst_state_alloc(struct dst_node *n);
+int dst_state_socket_create(struct dst_state *st);
+void dst_state_socket_release(struct dst_state *st);
+
+void dst_state_exit_connected(struct dst_state *st);
+
+int dst_state_schedule_receiver(struct dst_state *st);
+
+void dst_dump_addr(struct socket *sk, struct sockaddr *sa, char *str);
+
+static inline void dst_state_lock(struct dst_state *st)
+{
+ mutex_lock(&st->state_lock);
+}
+
+static inline void dst_state_unlock(struct dst_state *st)
+{
+ mutex_unlock(&st->state_lock);
+}
+
+void dst_poll_exit(struct dst_state *st);
+int dst_poll_init(struct dst_state *st);
+
+static inline unsigned int dst_state_poll(struct dst_state *st)
+{
+ unsigned int revents = POLLHUP | POLLERR;
+
+ dst_state_lock(st);
+ if (st->socket)
+ revents = st->socket->ops->poll(NULL, st->socket, NULL);
+ dst_state_unlock(st);
+
+ return revents;
+}
+
+static inline int dst_thread_setup(void *private, void *data)
+{
+ return 0;
+}
+
+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;
+}
+
+int dst_data_recv(struct dst_state *st, void *data, unsigned int size);
+int dst_recv_cdata(struct dst_state *st, void *cdata);
+int dst_data_send_header(struct socket *sock,
+ void *data, unsigned int size, int more);
+
+int dst_send_bio(struct dst_state *st, struct dst_cmd *cmd, struct bio *bio);
+
+int dst_process_io(struct dst_state *st);
+int dst_export_crypto(struct dst_node *n, struct bio *bio);
+int dst_export_send_bio(struct bio *bio);
+int dst_start_export(struct dst_node *n);
+
+int __init dst_export_init(void);
+void dst_export_exit(void);
+
+/* Private structure for export block IO requests */
+struct dst_export_priv
+{
+ struct list_head request_entry;
+ struct dst_state *state;
+ struct bio *bio;
+ struct dst_cmd cmd;
+};
+
+static inline void dst_trans_get(struct dst_trans *t)
+{
+ atomic_inc(&t->refcnt);
+}
+
+struct dst_trans *dst_trans_search(struct dst_node *node, dst_gen_t gen);
+int dst_trans_remove(struct dst_trans *t);
+int dst_trans_remove_nolock(struct dst_trans *t);
+void dst_trans_put(struct dst_trans *t);
+
+/*
+ * Convert bio into network command.
+ */
+static inline void dst_bio_to_cmd(struct bio *bio, struct dst_cmd *cmd,
+ u32 command, u64 id)
+{
+ cmd->cmd = command;
+ cmd->flags = (bio->bi_flags << BIO_POOL_BITS) >> BIO_POOL_BITS;
+ cmd->rw = bio->bi_rw;
+ cmd->size = bio->bi_size;
+ cmd->csize = 0;
+ cmd->id = id;
+ cmd->sector = bio->bi_sector;
+};
+
+int dst_trans_send(struct dst_trans *t);
+int dst_trans_crypto(struct dst_trans *t);
+
+int dst_node_crypto_init(struct dst_node *n, struct dst_crypto_ctl *ctl);
+void dst_node_crypto_exit(struct dst_node *n);
+
+static inline int dst_need_crypto(struct dst_node *n)
+{
+ struct dst_crypto_ctl *c = &n->crypto;
+ /*
+ * Logical OR is appropriate here, but boolean one produces
+ * more optimal code, so it is used instead.
+ */
+ return (c->hash_algo[0] | c->cipher_algo[0]);
+}
+
+int dst_node_trans_init(struct dst_node *n, unsigned int size);
+void dst_node_trans_exit(struct dst_node *n);
+
+/*
+ * Pool of threads.
+ * Ready list contains threads currently free to be used,
+ * active one contains threads with some work scheduled for them.
+ * Caller can wait in given queue when thread is ready.
+ */
+struct thread_pool
+{
+ int thread_num;
+ struct mutex thread_lock;
+ struct list_head ready_list, active_list;
+
+ wait_queue_head_t wait;
+};
+
+void thread_pool_del_worker(struct thread_pool *p);
+void thread_pool_del_worker_id(struct thread_pool *p, unsigned int id);
+int thread_pool_add_worker(struct thread_pool *p,
+ char *name,
+ unsigned int id,
+ void *(* init)(void *data),
+ void (* cleanup)(void *data),
+ void *data);
+
+void thread_pool_destroy(struct thread_pool *p);
+struct thread_pool *thread_pool_create(int num, char *name,
+ void *(* init)(void *data),
+ void (* cleanup)(void *data),
+ void *data);
+
+int thread_pool_schedule(struct thread_pool *p,
+ int (* setup)(void *stored_private, void *setup_data),
+ int (* action)(void *stored_private, void *setup_data),
+ void *setup_data, long timeout);
+int thread_pool_schedule_private(struct thread_pool *p,
+ int (* setup)(void *private, void *data),
+ int (* action)(void *private, void *data),
+ void *data, long timeout, void *id);
+
+#endif /* __KERNEL__ */
+#endif /* __DST_H */

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  Last update: 2008-11-25 15:53    [from the cache]
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