Hi.
DST is a network block device storage, which can be used to organize
exported storages on the remote nodes into the local block device.
Its main goal of the project is to allow creation of the block devices
on top of different network media and connect physically distributed devices
into the single storage using existing network infrastructure and not
introducing new limitations into the protocol and network usage model.
DST works on top of any network media and protocol, it is just a matter
of configuration utility to understand the correct addresses. The most
common example is TCP over IP allows to pass through firewalls and
created remote backup storage in the different datacenter. DST requires
single port to be enabled on the exporting node and outgoing connections
on the local node.
DST works with in-kernel client and server, which improves the performance
eliminating unneded data copies and allows not to depend on the version
of the external IO components. It requires userspace configuration utility
though.
DST uses transaction model, when each store has to be explicitly acked
from the remote node to be considered as successfully written. There
may be lots of in-flight transactions. When remote host does not ack
the transaction it will be resent predefined number of times with specified
timeouts between them. All those parameters are configurable. Transactions
are marked as failed after all resends completed unsuccessfully, having
long enough resend timeout and/or large number of resends allows not to
return error to the higher (FS usually) layer in case of short network
problems or remote node outages. In case of network RAID setup this means
that storage will not degrade until transactions are marked as failed, and
thus will not force checksum recalculation and data rebuild. In case of
connection failure DST will try to reconnect to the remote node automatically.
DST sends ping commands at idle time to detect if remote node is alive.
Because of transactional model it is possible to use zero-copy sending
without worry of data corruption (which in turn could be detected by the
strong checksums though).
DST may fully encrypt the data channel in case of untrusted channel and implement
strong checksum of the transferred data. It is possible to configure algorithms
and crypto keys, they should match on both sides of the network channel.
Crypto processing does not introduce noticeble performance overhead, since DST
uses configurable pool of threads to perform crypto processing.
Kernel does not yet support pool of threads, so this part is embedded into the DST.
DST utilizes memory pool model of all its transaction allocations (it is the
only additional allocation on the client) and server allocations (bio pools,
while pages are allocated from the slab).
At startup DST performs a simple negotiation with the export node to determine
access permissions and size of the exported storage. It can be extended if
new parameters should be autonegotiated.
DST carries block IO flags in the protocol, which allows to transparently implement
barriers and sync/flush operations. Those flags are used in the export node where
IO against the local storage is performed, which means that sync write will be sync
on the remote node too, which in turn improves data integrity and improved resistance
to errors and data corruption during power outages or storage damages.
Patches were split on per-file basis, so tree in the middle of the series will not
compile, which should not be a problem, since kconfig/makefile changes are introduced
in the latest patch.
There is an open maillist for DST development and discussion at dst @ ioremap.net
Short list of supported features:
* Kernel-side client and server. No need for any special tools for data processing
(like special userspace applications) except for configuration.
* Bullet-proof memory allocations via memory pools for all temporary objects
(transaction and so on). All clients structures are allocated as single transaction
from the memory pool and except this there is no allocation overhead. Network adds
own though. Server uses memory pools too, but number of allocations is higher
(bio, transaction and pages for IO).
* Zero-copy sending (except header) if supported by device using sendpage().
* Failover recovery in case of broken link (reconnection if remote node is down).
* Full transaction support (resending of the failed transactions on timeout of after
reconnect to failed node).
* Dynamically resizeable pool of threads used for data receiving and crypto processing.
* Initial autoconfiguration. Ability to extend it with additional attributes if needed.
* Support for barriers and other block io request flags.
* Support for any kind of network media (not limited to tcp or inet protocols) higher
MAC layer (socket layer). Out of the box kernel-side IPv6 support (needs to extend
configuration utility, check how it was done in POHMELFS).
* Security attributes for local export nodes (list of allowed to connect addresses with
permissions). Read-only connections.
* Ability to use any supported cryptographically strong checksums.
Ability to encrypt data channel.
* Keepalive messages to early detect failed nodes.
1. DST homepage.
http://www.ioremap.net/projects/dst
2. DST archive.
http://www.ioremap.net/archive/dst/
3. GIT trees.
http://www.ioremap.net/cgi-bin/gitweb.cgi
4. DST mail list.
[email protected]
Signed-off-by: Evgeniy Polyakov <[email protected]>
drivers/staging/Kconfig | 2 +
drivers/staging/Makefile | 2 +
drivers/block/dst/Kconfig | 71 +++
drivers/block/dst/Makefile | 3 +
drivers/block/dst/crypto.c | 731 +++++++++++++++++++++++++++++
drivers/block/dst/dcore.c | 972 +++++++++++++++++++++++++++++++++++++++
drivers/block/dst/export.c | 664 ++++++++++++++++++++++++++
drivers/block/dst/state.c | 839 +++++++++++++++++++++++++++++++++
drivers/block/dst/thread_pool.c | 345 ++++++++++++++
drivers/block/dst/trans.c | 335 ++++++++++++++
include/linux/connector.h | 4 +-
include/linux/dst.h | 587 +++++++++++++++++++++++
12 files changed, 4554 insertions(+), 1 deletions(-)
On Wed, Jan 14, 2009 at 02:05:33AM +0300, Evgeniy Polyakov ([email protected]) wrote:
> --- /dev/null
> +++ b/drivers/staging/dst/Kconfig
> @@ -0,0 +1,71 @@
> +config DST
> + tristate "Distributed storage"
> + depends on NET && CRYPTO && SYSFS
> + select CONNECTOR
> + select LIBCRC32C
Above is not needed.
--- ./drivers/staging/dst/Kconfig.old 2009-01-14 02:09:52.000000000 +0300
+++ ./drivers/staging/dst/Kconfig 2009-01-14 02:10:02.000000000 +0300
@@ -2,14 +2,10 @@
tristate "Distributed storage"
depends on NET && CRYPTO && SYSFS
select CONNECTOR
- select LIBCRC32C
---help---
DST is a network block device storage, which can be used to organize
exported storages on the remote nodes into the local block device.
- DST is a network block device storage, which can be used to organize
- exported storages on the remote nodes into the local block device.
-
DST works on top of any network media and protocol, it is just a matter
of configuration utility to understand the correct addresses. The most
common example is TCP over IP allows to pass through firewalls and
--
Evgeniy Polyakov
Kernel currently does not allow to queue work into some entity which
will perform it in the process context and have simple way to extend
number of worker and work with them not as separate objects, but with
pool as a whole. So thread pool model was implemented in the DST.
Thread pool abstraction allows to schedule a work to be performed
on behalf of kernel thread. One does not operate with threads itself,
instead user provides setup and cleanup callbacks for thread pool itself,
and action and cleanup callbacks for each submitted work.
Each worker has private data initialized at creation time and data,
provided by user at scheduling time.
When action is being performed, thread can not be used by other users,
instead they will sleep until there is free thread to pick their work.
Thread pool is used for crypto processing of incoming and outgoing IO
requests to reduce the overall overhead.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/thread_pool.c b/drivers/staging/dst/thread_pool.c
new file mode 100644
index 0000000..c35754d
--- /dev/null
+++ b/drivers/staging/dst/thread_pool.c
@@ -0,0 +1,345 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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/dst.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+
+/*
+ * Thread pool abstraction allows to schedule a work to be performed
+ * on behalf of kernel thread. One does not operate with threads itself,
+ * instead user provides setup and cleanup callbacks for thread pool itself,
+ * and action and cleanup callbacks for each submitted work.
+ *
+ * Each worker has private data initialized at creation time and data,
+ * provided by user at scheduling time.
+ *
+ * When action is being performed, thread can not be used by other users,
+ * instead they will sleep until there is free thread to pick their work.
+ */
+struct thread_pool_worker
+{
+ struct list_head worker_entry;
+
+ struct task_struct *thread;
+
+ struct thread_pool *pool;
+
+ int error;
+ int has_data;
+ int need_exit;
+ unsigned int id;
+
+ wait_queue_head_t wait;
+
+ void *private;
+ void *schedule_data;
+
+ int (* action)(void *private, void *schedule_data);
+ void (* cleanup)(void *private);
+};
+
+static void thread_pool_exit_worker(struct thread_pool_worker *w)
+{
+ kthread_stop(w->thread);
+
+ w->cleanup(w->private);
+ kfree(w);
+}
+
+/*
+ * Called to mark thread as ready and allow users to schedule new work.
+ */
+static void thread_pool_worker_make_ready(struct thread_pool_worker *w)
+{
+ struct thread_pool *p = w->pool;
+
+ mutex_lock(&p->thread_lock);
+
+ if (!w->need_exit) {
+ list_move_tail(&w->worker_entry, &p->ready_list);
+ w->has_data = 0;
+ mutex_unlock(&p->thread_lock);
+
+ wake_up(&p->wait);
+ } else {
+ p->thread_num--;
+ list_del(&w->worker_entry);
+ mutex_unlock(&p->thread_lock);
+
+ thread_pool_exit_worker(w);
+ }
+}
+
+/*
+ * Thread action loop: waits until there is new work.
+ */
+static int thread_pool_worker_func(void *data)
+{
+ struct thread_pool_worker *w = data;
+
+ while (!kthread_should_stop()) {
+ wait_event_interruptible(w->wait,
+ kthread_should_stop() || w->has_data);
+
+ if (kthread_should_stop())
+ break;
+
+ if (!w->has_data)
+ continue;
+
+ w->action(w->private, w->schedule_data);
+ thread_pool_worker_make_ready(w);
+ }
+
+ return 0;
+}
+
+/*
+ * Remove single worker without specifying which one.
+ */
+void thread_pool_del_worker(struct thread_pool *p)
+{
+ struct thread_pool_worker *w = NULL;
+
+ while (!w) {
+ wait_event(p->wait, !list_empty(&p->ready_list) || !p->thread_num);
+
+ dprintk("%s: locking list_empty: %d, thread_num: %d.\n",
+ __func__, list_empty(&p->ready_list), p->thread_num);
+
+ mutex_lock(&p->thread_lock);
+ if (!list_empty(&p->ready_list)) {
+ w = list_first_entry(&p->ready_list,
+ struct thread_pool_worker,
+ worker_entry);
+
+ dprintk("%s: deleting w: %p, thread_num: %d, list: %p [%p.%p].\n",
+ __func__, w, p->thread_num, &p->ready_list,
+ p->ready_list.prev, p->ready_list.next);
+
+ p->thread_num--;
+ list_del(&w->worker_entry);
+ }
+ mutex_unlock(&p->thread_lock);
+ }
+
+ if (w)
+ thread_pool_exit_worker(w);
+ dprintk("%s: deleted w: %p, thread_num: %d.\n",
+ __func__, w, p->thread_num);
+}
+
+/*
+ * Remove a worker with given ID.
+ */
+void thread_pool_del_worker_id(struct thread_pool *p, unsigned int id)
+{
+ struct thread_pool_worker *w;
+ int found = 0;
+
+ mutex_lock(&p->thread_lock);
+ list_for_each_entry(w, &p->ready_list, worker_entry) {
+ if (w->id == id) {
+ found = 1;
+ p->thread_num--;
+ list_del(&w->worker_entry);
+ break;
+ }
+ }
+
+ if (!found) {
+ list_for_each_entry(w, &p->active_list, worker_entry) {
+ if (w->id == id) {
+ w->need_exit = 1;
+ break;
+ }
+ }
+ }
+ mutex_unlock(&p->thread_lock);
+
+ if (found)
+ thread_pool_exit_worker(w);
+}
+
+/*
+ * Add new worker thread with given parameters.
+ * If initialization callback fails, return error.
+ */
+int thread_pool_add_worker(struct thread_pool *p,
+ char *name,
+ unsigned int id,
+ void *(* init)(void *private),
+ void (* cleanup)(void *private),
+ void *private)
+{
+ struct thread_pool_worker *w;
+ int err = -ENOMEM;
+
+ w = kzalloc(sizeof(struct thread_pool_worker), GFP_KERNEL);
+ if (!w)
+ goto err_out_exit;
+
+ w->pool = p;
+ init_waitqueue_head(&w->wait);
+ w->cleanup = cleanup;
+ w->id = id;
+
+ w->thread = kthread_run(thread_pool_worker_func, w, "%s", name);
+ if (IS_ERR(w->thread)) {
+ err = PTR_ERR(w->thread);
+ goto err_out_free;
+ }
+
+ w->private = init(private);
+ if (IS_ERR(w->private)) {
+ err = PTR_ERR(w->private);
+ goto err_out_stop_thread;
+ }
+
+ mutex_lock(&p->thread_lock);
+ list_add_tail(&w->worker_entry, &p->ready_list);
+ p->thread_num++;
+ mutex_unlock(&p->thread_lock);
+
+ return 0;
+
+err_out_stop_thread:
+ kthread_stop(w->thread);
+err_out_free:
+ kfree(w);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Destroy the whole pool.
+ */
+void thread_pool_destroy(struct thread_pool *p)
+{
+ while (p->thread_num) {
+ dprintk("%s: num: %d.\n", __func__, p->thread_num);
+ thread_pool_del_worker(p);
+ }
+
+ kfree(p);
+}
+
+/*
+ * Create a pool with given number of threads.
+ * They will have sequential IDs started from zero.
+ */
+struct thread_pool *thread_pool_create(int num, char *name,
+ void *(* init)(void *private),
+ void (* cleanup)(void *private),
+ void *private)
+{
+ struct thread_pool_worker *w, *tmp;
+ struct thread_pool *p;
+ int err = -ENOMEM;
+ int i;
+
+ p = kzalloc(sizeof(struct thread_pool), GFP_KERNEL);
+ if (!p)
+ goto err_out_exit;
+
+ init_waitqueue_head(&p->wait);
+ mutex_init(&p->thread_lock);
+ INIT_LIST_HEAD(&p->ready_list);
+ INIT_LIST_HEAD(&p->active_list);
+ p->thread_num = 0;
+
+ for (i=0; i<num; ++i) {
+ err = thread_pool_add_worker(p, name, i, init,
+ cleanup, private);
+ if (err)
+ goto err_out_free_all;
+ }
+
+ return p;
+
+err_out_free_all:
+ list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) {
+ list_del(&w->worker_entry);
+ thread_pool_exit_worker(w);
+ }
+ kfree(p);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+/*
+ * Schedule execution of the action on a given thread,
+ * provided ID pointer has to match previously stored
+ * private data.
+ */
+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)
+{
+ struct thread_pool_worker *w, *tmp, *worker = NULL;
+ int err = 0;
+
+ while (!worker && !err) {
+ timeout = wait_event_interruptible_timeout(p->wait,
+ !list_empty(&p->ready_list),
+ timeout);
+
+ if (!timeout) {
+ err = -ETIMEDOUT;
+ break;
+ }
+
+ worker = NULL;
+ mutex_lock(&p->thread_lock);
+ list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) {
+ if (id && id != w->private)
+ continue;
+
+ worker = w;
+
+ list_move_tail(&w->worker_entry, &p->active_list);
+
+ err = setup(w->private, data);
+ if (!err) {
+ w->schedule_data = data;
+ w->action = action;
+ w->has_data = 1;
+ wake_up(&w->wait);
+ } else {
+ list_move_tail(&w->worker_entry, &p->ready_list);
+ }
+
+ break;
+ }
+ mutex_unlock(&p->thread_lock);
+ }
+
+ return err;
+}
+
+/*
+ * Schedule execution on arbitrary thread from the pool.
+ */
+int thread_pool_schedule(struct thread_pool *p,
+ int (* setup)(void *private, void *data),
+ int (* action)(void *private, void *data),
+ void *data, long timeout)
+{
+ return thread_pool_schedule_private(p, setup,
+ action, data, timeout, NULL);
+}
DST uses transaction model, when each store has to be explicitly acked
from the remote node to be considered as successfully written. There
may be lots of in-flight transactions. When remote host does not ack
the transaction it will be resent predefined number of times with specified
timeouts between them. All those parameters are configurable. Transactions
are marked as failed after all resends completed unsuccessfully, having
long enough resend timeout and/or large number of resends allows not to
return error to the higher (FS usually) layer in case of short network
problems or remote node outages. In case of network RAID setup this means
that storage will not degrade until transactions are marked as failed, and
thus will not force checksum recalculation and data rebuild. In case of
connection failure DST will try to reconnect to the remote node automatically.
DST sends ping commands at idle time to detect if remote node is alive.
Because of transactional model it is possible to use zero-copy sending
without worry of data corruption (which in turn could be detected by the
strong checksums though).
Transactions are handled in this patch: allocation/freeing/completion,
scanning for stall and to-be-resent transactions and overall management
of the storing tree.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/trans.c b/drivers/staging/dst/trans.c
new file mode 100644
index 0000000..557d372
--- /dev/null
+++ b/drivers/staging/dst/trans.c
@@ -0,0 +1,335 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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;
+}
This patch introduces remote (export) node machinery: initialization
address/port (and other socket parameters), export block device (can be
another DST storage for example or local device like /dev/sda1), local
IO processing engine (BIO state machines, receiving/submitting logic).
Network management for the export node like accepting new client, scheduling
its command processing thread, receiving/sending IO requests, all are placed
here.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/export.c b/drivers/staging/dst/export.c
new file mode 100644
index 0000000..122fe75
--- /dev/null
+++ b/drivers/staging/dst/export.c
@@ -0,0 +1,664 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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/blkdev.h>
+#include <linux/bio.h>
+#include <linux/dst.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/socket.h>
+
+#include <net/sock.h>
+
+/*
+ * Export bioset is used for server block IO requests.
+ */
+static struct bio_set *dst_bio_set;
+
+int __init dst_export_init(void)
+{
+ int err = -ENOMEM;
+
+ dst_bio_set = bioset_create(32, 32);
+ if (!dst_bio_set)
+ goto err_out_exit;
+
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+void dst_export_exit(void)
+{
+ bioset_free(dst_bio_set);
+}
+
+/*
+ * When client connects and autonegotiates with the server node,
+ * its permissions are checked in a security attributes and sent
+ * back.
+ */
+static unsigned int dst_check_permissions(struct dst_state *main, struct dst_state *st)
+{
+ struct dst_node *n = main->node;
+ struct dst_secure *sentry;
+ struct dst_secure_user *s;
+ struct saddr *sa = &st->ctl.addr;
+ unsigned int perm = 0;
+
+ mutex_lock(&n->security_lock);
+ list_for_each_entry(sentry, &n->security_list, sec_entry) {
+ s = &sentry->sec;
+
+ if (s->addr.sa_family != sa->sa_family)
+ continue;
+
+ if (s->addr.sa_data_len != sa->sa_data_len)
+ continue;
+
+ /*
+ * This '2' below is a port field. This may be very wrong to do
+ * in atalk for example though. If there will be any need to extent
+ * protocol to something else, I can create per-family helpers and
+ * use them instead of this memcmp.
+ */
+ if (memcmp(s->addr.sa_data + 2, sa->sa_data + 2,
+ sa->sa_data_len - 2))
+ continue;
+
+ perm = s->permissions;
+ }
+ mutex_unlock(&n->security_lock);
+
+ return perm;
+}
+
+/*
+ * Accept new client: allocate appropriate network state and check permissions.
+ */
+static struct dst_state *dst_accept_client(struct dst_state *st)
+{
+ unsigned int revents = 0;
+ unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP;
+ unsigned int mask = err_mask | POLLIN;
+ struct dst_node *n = st->node;
+ int err = 0;
+ struct socket *sock = NULL;
+ struct dst_state *new;
+
+ while (!err && !sock) {
+ revents = dst_state_poll(st);
+
+ if (!(revents & mask)) {
+ DEFINE_WAIT(wait);
+
+ for (;;) {
+ prepare_to_wait(&st->thread_wait,
+ &wait, TASK_INTERRUPTIBLE);
+ if (!n->trans_scan_timeout || st->need_exit)
+ break;
+
+ revents = dst_state_poll(st);
+
+ if (revents & mask)
+ break;
+
+ if (signal_pending(current))
+ break;
+
+ /*
+ * Magic HZ? Polling check above is not safe in
+ * all cases (like socket reset in BH context),
+ * so it is simpler just to postpone it to the
+ * process context instead of implementing special
+ * locking there.
+ */
+ schedule_timeout(HZ);
+ }
+ finish_wait(&st->thread_wait, &wait);
+ }
+
+ err = -ECONNRESET;
+ dst_state_lock(st);
+
+ dprintk("%s: st: %p, revents: %x [err: %d, in: %d].\n",
+ __func__, st, revents, revents & err_mask,
+ revents & POLLIN);
+
+ if (revents & err_mask) {
+ dprintk("%s: revents: %x, socket: %p, err: %d.\n",
+ __func__, revents, st->socket, err);
+ err = -ECONNRESET;
+ }
+
+ if (!n->trans_scan_timeout || st->need_exit)
+ err = -ENODEV;
+
+ if (st->socket && (revents & POLLIN))
+ err = kernel_accept(st->socket, &sock, 0);
+
+ dst_state_unlock(st);
+ }
+
+ if (err)
+ goto err_out_exit;
+
+ new = dst_state_alloc(st->node);
+ if (!new) {
+ err = -ENOMEM;
+ goto err_out_release;
+ }
+ new->socket = sock;
+
+ new->ctl.addr.sa_data_len = sizeof(struct sockaddr);
+ err = kernel_getpeername(sock, (struct sockaddr *)&new->ctl.addr,
+ (int *)&new->ctl.addr.sa_data_len);
+ if (err)
+ goto err_out_put;
+
+ new->permissions = dst_check_permissions(st, new);
+ if (new->permissions == 0) {
+ err = -EPERM;
+ dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr,
+ "Client is not allowed to connect");
+ goto err_out_put;
+ }
+
+ err = dst_poll_init(new);
+ if (err)
+ goto err_out_put;
+
+ dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr,
+ "Connected client");
+
+ return new;
+
+err_out_put:
+ dst_state_put(new);
+err_out_release:
+ sock_release(sock);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+/*
+ * Each server's block request sometime finishes.
+ * Usually it happens in hard irq context of the appropriate controller,
+ * so to play good with all cases we just queue BIO into the queue
+ * and wake up processing thread, which gets completed request and
+ * send (encrypting if needed) it back to the client (if it was a read
+ * request), or sends back reply that writing succesfully completed.
+ */
+static int dst_export_process_request_queue(struct dst_state *st)
+{
+ unsigned long flags;
+ struct dst_export_priv *p = NULL;
+ struct bio *bio;
+ int err = 0;
+
+ while (!list_empty(&st->request_list)) {
+ spin_lock_irqsave(&st->request_lock, flags);
+ if (!list_empty(&st->request_list)) {
+ p = list_first_entry(&st->request_list,
+ struct dst_export_priv, request_entry);
+ list_del(&p->request_entry);
+ }
+ spin_unlock_irqrestore(&st->request_lock, flags);
+
+ if (!p)
+ break;
+
+ bio = p->bio;
+
+ if (dst_need_crypto(st->node) && (bio_data_dir(bio) == READ))
+ err = dst_export_crypto(st->node, bio);
+ else
+ err = dst_export_send_bio(bio);
+
+ if (err)
+ break;
+ }
+
+ return err;
+}
+
+/*
+ * Cleanup export state.
+ * It has to wait until all requests are finished,
+ * and then free them all.
+ */
+static void dst_state_cleanup_export(struct dst_state *st)
+{
+ struct dst_export_priv *p;
+ unsigned long flags;
+
+ /*
+ * This loop waits for all pending bios to be completed and freed.
+ */
+ while (atomic_read(&st->refcnt) > 1) {
+ dprintk("%s: st: %p, refcnt: %d, list_empty: %d.\n",
+ __func__, st, atomic_read(&st->refcnt),
+ list_empty(&st->request_list));
+ wait_event_timeout(st->thread_wait,
+ (atomic_read(&st->refcnt) == 1) ||
+ !list_empty(&st->request_list),
+ HZ/2);
+
+ while (!list_empty(&st->request_list)) {
+ p = NULL;
+ spin_lock_irqsave(&st->request_lock, flags);
+ if (!list_empty(&st->request_list)) {
+ p = list_first_entry(&st->request_list,
+ struct dst_export_priv, request_entry);
+ list_del(&p->request_entry);
+ }
+ spin_unlock_irqrestore(&st->request_lock, flags);
+
+ if (p)
+ bio_put(p->bio);
+
+ dprintk("%s: st: %p, refcnt: %d, list_empty: %d, p: %p.\n",
+ __func__, st, atomic_read(&st->refcnt),
+ list_empty(&st->request_list), p);
+ }
+ }
+
+ dst_state_put(st);
+}
+
+/*
+ * Client accepting thread.
+ * Not only accepts new connection, but also schedules receiving thread
+ * and performs request completion described above.
+ */
+static int dst_accept(void *init_data, void *schedule_data)
+{
+ struct dst_state *main_st = schedule_data;
+ struct dst_node *n = init_data;
+ struct dst_state *st;
+ int err;
+
+ while (n->trans_scan_timeout && !main_st->need_exit) {
+ dprintk("%s: main_st: %p, n: %p.\n", __func__, main_st, n);
+ st = dst_accept_client(main_st);
+ if (IS_ERR(st))
+ continue;
+
+ err = dst_state_schedule_receiver(st);
+ if (!err) {
+ while (n->trans_scan_timeout) {
+ err = wait_event_interruptible_timeout(st->thread_wait,
+ !list_empty(&st->request_list) ||
+ !n->trans_scan_timeout ||
+ st->need_exit,
+ HZ);
+
+ if (!n->trans_scan_timeout || st->need_exit)
+ break;
+
+ if (list_empty(&st->request_list))
+ continue;
+
+ err = dst_export_process_request_queue(st);
+ if (err)
+ break;
+ }
+
+ st->need_exit = 1;
+ wake_up(&st->thread_wait);
+ }
+
+ dst_state_cleanup_export(st);
+ }
+
+ dprintk("%s: freeing listening socket st: %p.\n", __func__, main_st);
+
+ dst_state_lock(main_st);
+ dst_poll_exit(main_st);
+ dst_state_socket_release(main_st);
+ dst_state_unlock(main_st);
+ dst_state_put(main_st);
+ dprintk("%s: freed listening socket st: %p.\n", __func__, main_st);
+
+ return 0;
+}
+
+int dst_start_export(struct dst_node *n)
+{
+ if (list_empty(&n->security_list)) {
+ printk(KERN_ERR "You are trying to export node '%s' without security attributes.\n"
+ "No clients will be allowed to connect. Exiting.\n", n->name);
+ return -EINVAL;
+ }
+ return dst_node_trans_init(n, sizeof(struct dst_export_priv));
+}
+
+/*
+ * Initialize listening state and schedule accepting thread.
+ */
+int dst_node_init_listened(struct dst_node *n, struct dst_export_ctl *le)
+{
+ struct dst_state *st;
+ int err = -ENOMEM;
+ struct dst_network_ctl *ctl = &le->ctl;
+
+ memcpy(&n->info->net, ctl, sizeof(struct dst_network_ctl));
+
+ st = dst_state_alloc(n);
+ if (IS_ERR(st)) {
+ err = PTR_ERR(st);
+ goto err_out_exit;
+ }
+ memcpy(&st->ctl, ctl, sizeof(struct dst_network_ctl));
+
+ err = dst_state_socket_create(st);
+ if (err)
+ goto err_out_put;
+
+ st->socket->sk->sk_reuse = 1;
+
+ err = kernel_bind(st->socket, (struct sockaddr *)&ctl->addr,
+ ctl->addr.sa_data_len);
+ if (err)
+ goto err_out_socket_release;
+
+ err = kernel_listen(st->socket, 1024);
+ if (err)
+ goto err_out_socket_release;
+ n->state = st;
+
+ err = dst_poll_init(st);
+ if (err)
+ goto err_out_socket_release;
+
+ dst_state_get(st);
+
+ err = thread_pool_schedule(n->pool, dst_thread_setup,
+ dst_accept, st, MAX_SCHEDULE_TIMEOUT);
+ if (err)
+ goto err_out_poll_exit;
+
+ return 0;
+
+err_out_poll_exit:
+ dst_poll_exit(st);
+err_out_socket_release:
+ dst_state_socket_release(st);
+err_out_put:
+ dst_state_put(st);
+err_out_exit:
+ n->state = NULL;
+ return err;
+}
+
+/*
+ * Free bio and related private data.
+ * Also drop a reference counter for appropriate state,
+ * which waits when there are no more block IOs in-flight.
+ */
+static void dst_bio_destructor(struct bio *bio)
+{
+ struct bio_vec *bv;
+ struct dst_export_priv *priv = bio->bi_private;
+ int i;
+
+ bio_for_each_segment(bv, bio, i) {
+ if (!bv->bv_page)
+ break;
+
+ __free_page(bv->bv_page);
+ }
+
+ if (priv) {
+ struct dst_node *n = priv->state->node;
+
+ dst_state_put(priv->state);
+ mempool_free(priv, n->trans_pool);
+ }
+ bio_free(bio, dst_bio_set);
+}
+
+/*
+ * Block IO completion. Queue request to be sent back to
+ * the client (or just confirmation).
+ */
+static void dst_bio_end_io(struct bio *bio, int err)
+{
+ struct dst_export_priv *p = bio->bi_private;
+ struct dst_state *st = p->state;
+ unsigned long flags;
+
+ spin_lock_irqsave(&st->request_lock, flags);
+ list_add_tail(&p->request_entry, &st->request_list);
+ spin_unlock_irqrestore(&st->request_lock, flags);
+
+ wake_up(&st->thread_wait);
+}
+
+/*
+ * Allocate read request for the server.
+ */
+static int dst_export_read_request(struct bio *bio, unsigned int total_size)
+{
+ unsigned int size;
+ struct page *page;
+ int err;
+
+ while (total_size) {
+ err = -ENOMEM;
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ goto err_out_exit;
+
+ size = min_t(unsigned int, PAGE_SIZE, total_size);
+
+ err = bio_add_page(bio, page, size, 0);
+ dprintk("%s: bio: %llu/%u, size: %u, err: %d.\n",
+ __func__, (u64)bio->bi_sector, bio->bi_size,
+ size, err);
+ if (err <= 0)
+ goto err_out_free_page;
+
+ total_size -= size;
+ }
+
+ return 0;
+
+err_out_free_page:
+ __free_page(page);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Allocate write request for the server.
+ * Should not only get pages, but also read data from the network.
+ */
+static int dst_export_write_request(struct dst_state *st,
+ struct bio *bio, unsigned int total_size)
+{
+ unsigned int size;
+ struct page *page;
+ void *data;
+ int err;
+
+ while (total_size) {
+ err = -ENOMEM;
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ goto err_out_exit;
+
+ data = kmap(page);
+ if (!data)
+ goto err_out_free_page;
+
+ size = min_t(unsigned int, PAGE_SIZE, total_size);
+
+ err = dst_data_recv(st, data, size);
+ if (err)
+ goto err_out_unmap_page;
+
+ err = bio_add_page(bio, page, size, 0);
+ if (err <= 0)
+ goto err_out_unmap_page;
+
+ kunmap(page);
+
+ total_size -= size;
+ }
+
+ return 0;
+
+err_out_unmap_page:
+ kunmap(page);
+err_out_free_page:
+ __free_page(page);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Groovy, we've gotten an IO request from the client.
+ * Allocate BIO from the bioset, private data from the mempool
+ * and lots of pages for IO.
+ */
+int dst_process_io(struct dst_state *st)
+{
+ struct dst_node *n = st->node;
+ struct dst_cmd *cmd = st->data;
+ struct bio *bio;
+ struct dst_export_priv *priv;
+ int err = -ENOMEM;
+
+ if (unlikely(!n->bdev)) {
+ err = -EINVAL;
+ goto err_out_exit;
+ }
+
+ bio = bio_alloc_bioset(GFP_KERNEL,
+ PAGE_ALIGN(cmd->size) >> PAGE_SHIFT,
+ dst_bio_set);
+ if (!bio)
+ goto err_out_exit;
+ bio->bi_private = NULL;
+
+ priv = mempool_alloc(st->node->trans_pool, GFP_KERNEL);
+ if (!priv)
+ goto err_out_free;
+
+ priv->state = dst_state_get(st);
+ priv->bio = bio;
+
+ bio->bi_private = priv;
+ bio->bi_end_io = dst_bio_end_io;
+ bio->bi_destructor = dst_bio_destructor;
+ bio->bi_bdev = n->bdev;
+
+ /*
+ * Server side is only interested in two low bits:
+ * uptodate (set by itself actually) and rw block
+ */
+ bio->bi_flags |= cmd->flags & 3;
+
+ bio->bi_rw = cmd->rw;
+ bio->bi_size = 0;
+ bio->bi_sector = cmd->sector;
+
+ dst_bio_to_cmd(bio, &priv->cmd, DST_IO_RESPONSE, cmd->id);
+
+ priv->cmd.flags = 0;
+ priv->cmd.size = cmd->size;
+
+ if (bio_data_dir(bio) == WRITE) {
+ err = dst_recv_cdata(st, priv->cmd.hash);
+ if (err)
+ goto err_out_free;
+
+ err = dst_export_write_request(st, bio, cmd->size);
+ if (err)
+ goto err_out_free;
+
+ if (dst_need_crypto(n))
+ return dst_export_crypto(n, bio);
+ } else {
+ err = dst_export_read_request(bio, cmd->size);
+ if (err)
+ goto err_out_free;
+ }
+
+ dprintk("%s: bio: %llu/%u, rw: %lu, dir: %lu, flags: %lx, phys: %d.\n",
+ __func__, (u64)bio->bi_sector, bio->bi_size,
+ bio->bi_rw, bio_data_dir(bio),
+ bio->bi_flags, bio->bi_phys_segments);
+
+ generic_make_request(bio);
+
+ return 0;
+
+err_out_free:
+ bio_put(bio);
+err_out_exit:
+ return err;
+}
+
+/*
+ * Ok, block IO is ready, let's send it back to the client...
+ */
+int dst_export_send_bio(struct bio *bio)
+{
+ struct dst_export_priv *p = bio->bi_private;
+ struct dst_state *st = p->state;
+ struct dst_cmd *cmd = &p->cmd;
+ int err;
+
+ dprintk("%s: id: %llu, bio: %llu/%u, csize: %u, flags: %lu, rw: %lu.\n",
+ __func__, cmd->id, (u64)bio->bi_sector, bio->bi_size,
+ cmd->csize, bio->bi_flags, bio->bi_rw);
+
+ dst_convert_cmd(cmd);
+
+ dst_state_lock(st);
+ if (!st->socket) {
+ err = -ECONNRESET;
+ goto err_out_unlock;
+ }
+
+ if (bio_data_dir(bio) == WRITE) {
+ /* ... or just confirmation that writing has completed. */
+ cmd->size = cmd->csize = 0;
+ err = dst_data_send_header(st->socket, cmd,
+ sizeof(struct dst_cmd), 0);
+ if (err)
+ goto err_out_unlock;
+ } else {
+ err = dst_send_bio(st, cmd, bio);
+ if (err)
+ goto err_out_unlock;
+ }
+
+ dst_state_unlock(st);
+
+ bio_put(bio);
+ return 0;
+
+err_out_unlock:
+ dst_state_unlock(st);
+
+ bio_put(bio);
+ return err;
+}
DST may fully encrypt the data channel in case of untrusted channel and implement
strong checksum of the transferred data. It is possible to configure algorithms
and crypto keys, they should match on both sides of the network channel.
Crypto processing does not introduce noticeble performance overhead, since DST
uses configurable pool of threads to perform crypto processing.
This patch introduces crypto processing helpers and crypto engine initialization:
glueing with the crypto layer, allocation and initialization of the crypto
processing thread pool, allocation of the cached pages, which are used to temporary
encrypt data into, since it is forbidden to encrypt data in-place, since pages
are used by the higher layers.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/crypto.c b/drivers/staging/dst/crypto.c
new file mode 100644
index 0000000..7250f90
--- /dev/null
+++ b/drivers/staging/dst/crypto.c
@@ -0,0 +1,731 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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/crypto.h>
+#include <linux/dst.h>
+#include <linux/kernel.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+/*
+ * Tricky bastard, but IV can be more complex with time...
+ */
+static inline u64 dst_gen_iv(struct dst_trans *t)
+{
+ return t->gen;
+}
+
+/*
+ * Crypto machinery: hash/cipher support for the given crypto controls.
+ */
+static struct crypto_hash *dst_init_hash(struct dst_crypto_ctl *ctl, u8 *key)
+{
+ int err;
+ struct crypto_hash *hash;
+
+ hash = crypto_alloc_hash(ctl->hash_algo, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hash)) {
+ err = PTR_ERR(hash);
+ dprintk("%s: failed to allocate hash '%s', err: %d.\n",
+ __func__, ctl->hash_algo, err);
+ goto err_out_exit;
+ }
+
+ ctl->crypto_attached_size = crypto_hash_digestsize(hash);
+
+ if (!ctl->hash_keysize)
+ return hash;
+
+ err = crypto_hash_setkey(hash, key, ctl->hash_keysize);
+ if (err) {
+ dprintk("%s: failed to set key for hash '%s', err: %d.\n",
+ __func__, ctl->hash_algo, err);
+ goto err_out_free;
+ }
+
+ return hash;
+
+err_out_free:
+ crypto_free_hash(hash);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+static struct crypto_ablkcipher *dst_init_cipher(struct dst_crypto_ctl *ctl, u8 *key)
+{
+ int err = -EINVAL;
+ struct crypto_ablkcipher *cipher;
+
+ if (!ctl->cipher_keysize)
+ goto err_out_exit;
+
+ cipher = crypto_alloc_ablkcipher(ctl->cipher_algo, 0, 0);
+ if (IS_ERR(cipher)) {
+ err = PTR_ERR(cipher);
+ dprintk("%s: failed to allocate cipher '%s', err: %d.\n",
+ __func__, ctl->cipher_algo, err);
+ goto err_out_exit;
+ }
+
+ crypto_ablkcipher_clear_flags(cipher, ~0);
+
+ err = crypto_ablkcipher_setkey(cipher, key, ctl->cipher_keysize);
+ if (err) {
+ dprintk("%s: failed to set key for cipher '%s', err: %d.\n",
+ __func__, ctl->cipher_algo, err);
+ goto err_out_free;
+ }
+
+ return cipher;
+
+err_out_free:
+ crypto_free_ablkcipher(cipher);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+/*
+ * Crypto engine has a pool of pages to encrypt data into before sending
+ * it over the network. This pool is freed/allocated here.
+ */
+static void dst_crypto_pages_free(struct dst_crypto_engine *e)
+{
+ unsigned int i;
+
+ for (i=0; i<e->page_num; ++i)
+ __free_page(e->pages[i]);
+ kfree(e->pages);
+}
+
+static int dst_crypto_pages_alloc(struct dst_crypto_engine *e, int num)
+{
+ int i;
+
+ e->pages = kmalloc(num * sizeof(struct page **), GFP_KERNEL);
+ if (!e->pages)
+ return -ENOMEM;
+
+ for (i=0; i<num; ++i) {
+ e->pages[i] = alloc_page(GFP_KERNEL);
+ if (!e->pages[i])
+ goto err_out_free_pages;
+ }
+
+ e->page_num = num;
+ return 0;
+
+err_out_free_pages:
+ while (--i >= 0)
+ __free_page(e->pages[i]);
+
+ kfree(e->pages);
+ return -ENOMEM;
+}
+
+/*
+ * Initialize crypto engine for given node.
+ * Setup cipher/hash, keys, pool of threads and private data.
+ */
+static int dst_crypto_engine_init(struct dst_crypto_engine *e, struct dst_node *n)
+{
+ int err;
+ struct dst_crypto_ctl *ctl = &n->crypto;
+
+ err = dst_crypto_pages_alloc(e, n->max_pages);
+ if (err)
+ goto err_out_exit;
+
+ e->size = PAGE_SIZE;
+ e->data = kmalloc(e->size, GFP_KERNEL);
+ if (!e->data) {
+ err = -ENOMEM;
+ goto err_out_free_pages;
+ }
+
+ if (ctl->hash_algo[0]) {
+ e->hash = dst_init_hash(ctl, n->hash_key);
+ if (IS_ERR(e->hash)) {
+ err = PTR_ERR(e->hash);
+ e->hash = NULL;
+ goto err_out_free;
+ }
+ }
+
+ if (ctl->cipher_algo[0]) {
+ e->cipher = dst_init_cipher(ctl, n->cipher_key);
+ if (IS_ERR(e->cipher)) {
+ err = PTR_ERR(e->cipher);
+ e->cipher = NULL;
+ goto err_out_free_hash;
+ }
+ }
+
+ return 0;
+
+err_out_free_hash:
+ crypto_free_hash(e->hash);
+err_out_free:
+ kfree(e->data);
+err_out_free_pages:
+ dst_crypto_pages_free(e);
+err_out_exit:
+ return err;
+}
+
+static void dst_crypto_engine_exit(struct dst_crypto_engine *e)
+{
+ if (e->hash)
+ crypto_free_hash(e->hash);
+ if (e->cipher)
+ crypto_free_ablkcipher(e->cipher);
+ dst_crypto_pages_free(e);
+ kfree(e->data);
+}
+
+/*
+ * Waiting for cipher processing to be completed.
+ */
+struct dst_crypto_completion
+{
+ struct completion complete;
+ int error;
+};
+
+static void dst_crypto_complete(struct crypto_async_request *req, int err)
+{
+ struct dst_crypto_completion *c = req->data;
+
+ if (err == -EINPROGRESS)
+ return;
+
+ dprintk("%s: req: %p, err: %d.\n", __func__, req, err);
+ c->error = err;
+ complete(&c->complete);
+}
+
+static int dst_crypto_process(struct ablkcipher_request *req,
+ struct scatterlist *sg_dst, struct scatterlist *sg_src,
+ void *iv, int enc, unsigned long timeout)
+{
+ struct dst_crypto_completion c;
+ int err;
+
+ init_completion(&c.complete);
+ c.error = -EINPROGRESS;
+
+ ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ dst_crypto_complete, &c);
+
+ ablkcipher_request_set_crypt(req, sg_src, sg_dst, sg_src->length, iv);
+
+ if (enc)
+ err = crypto_ablkcipher_encrypt(req);
+ else
+ err = crypto_ablkcipher_decrypt(req);
+
+ switch (err) {
+ case -EINPROGRESS:
+ case -EBUSY:
+ err = wait_for_completion_interruptible_timeout(&c.complete,
+ timeout);
+ if (!err)
+ err = -ETIMEDOUT;
+ else
+ err = c.error;
+ break;
+ default:
+ break;
+ }
+
+ return err;
+}
+
+/*
+ * DST uses generic iteration approach for data crypto processing.
+ * Single block IO request is switched into array of scatterlists,
+ * which are submitted to the crypto processing iterator.
+ *
+ * Input and output iterator initialization are different, since
+ * in output case we can not encrypt data in-place and need a
+ * temporary storage, which is then being sent to the remote peer.
+ */
+static int dst_trans_iter_out(struct bio *bio, struct dst_crypto_engine *e,
+ int (* iterator) (struct dst_crypto_engine *e,
+ struct scatterlist *dst,
+ struct scatterlist *src))
+{
+ struct bio_vec *bv;
+ int err, i;
+
+ sg_init_table(e->src, bio->bi_vcnt);
+ sg_init_table(e->dst, bio->bi_vcnt);
+
+ bio_for_each_segment(bv, bio, i) {
+ sg_set_page(&e->src[i], bv->bv_page, bv->bv_len, bv->bv_offset);
+ sg_set_page(&e->dst[i], e->pages[i], bv->bv_len, bv->bv_offset);
+
+ err = iterator(e, &e->dst[i], &e->src[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int dst_trans_iter_in(struct bio *bio, struct dst_crypto_engine *e,
+ int (* iterator) (struct dst_crypto_engine *e,
+ struct scatterlist *dst,
+ struct scatterlist *src))
+{
+ struct bio_vec *bv;
+ int err, i;
+
+ sg_init_table(e->src, bio->bi_vcnt);
+ sg_init_table(e->dst, bio->bi_vcnt);
+
+ bio_for_each_segment(bv, bio, i) {
+ sg_set_page(&e->src[i], bv->bv_page, bv->bv_len, bv->bv_offset);
+ sg_set_page(&e->dst[i], bv->bv_page, bv->bv_len, bv->bv_offset);
+
+ err = iterator(e, &e->dst[i], &e->src[i]);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int dst_crypt_iterator(struct dst_crypto_engine *e,
+ struct scatterlist *sg_dst, struct scatterlist *sg_src)
+{
+ struct ablkcipher_request *req = e->data;
+ u8 iv[32];
+
+ memset(iv, 0, sizeof(iv));
+
+ memcpy(iv, &e->iv, sizeof(e->iv));
+
+ return dst_crypto_process(req, sg_dst, sg_src, iv, e->enc, e->timeout);
+}
+
+static int dst_crypt(struct dst_crypto_engine *e, struct bio *bio)
+{
+ struct ablkcipher_request *req = e->data;
+
+ memset(req, 0, sizeof(struct ablkcipher_request));
+ ablkcipher_request_set_tfm(req, e->cipher);
+
+ if (e->enc)
+ return dst_trans_iter_out(bio, e, dst_crypt_iterator);
+ else
+ return dst_trans_iter_in(bio, e, dst_crypt_iterator);
+}
+
+static int dst_hash_iterator(struct dst_crypto_engine *e,
+ struct scatterlist *sg_dst, struct scatterlist *sg_src)
+{
+ return crypto_hash_update(e->data, sg_src, sg_src->length);
+}
+
+static int dst_hash(struct dst_crypto_engine *e, struct bio *bio, void *dst)
+{
+ struct hash_desc *desc = e->data;
+ int err;
+
+ desc->tfm = e->hash;
+ desc->flags = 0;
+
+ err = crypto_hash_init(desc);
+ if (err)
+ return err;
+
+ err = dst_trans_iter_in(bio, e, dst_hash_iterator);
+ if (err)
+ return err;
+
+ err = crypto_hash_final(desc, dst);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+/*
+ * Initialize/cleanup a crypto thread. The only thing it should
+ * do is to allocate a pool of pages as temporary storage.
+ * And to setup cipher and/or hash.
+ */
+static void *dst_crypto_thread_init(void *data)
+{
+ struct dst_node *n = data;
+ struct dst_crypto_engine *e;
+ int err = -ENOMEM;
+
+ e = kzalloc(sizeof(struct dst_crypto_engine), GFP_KERNEL);
+ if (!e)
+ goto err_out_exit;
+ e->src = kcalloc(2 * n->max_pages, sizeof(struct scatterlist),
+ GFP_KERNEL);
+ if (!e->src)
+ goto err_out_free;
+
+ e->dst = e->src + n->max_pages;
+
+ err = dst_crypto_engine_init(e, n);
+ if (err)
+ goto err_out_free_all;
+
+ return e;
+
+err_out_free_all:
+ kfree(e->src);
+err_out_free:
+ kfree(e);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+static void dst_crypto_thread_cleanup(void *private)
+{
+ struct dst_crypto_engine *e = private;
+
+ dst_crypto_engine_exit(e);
+ kfree(e->src);
+ kfree(e);
+}
+
+/*
+ * Initialize crypto engine for given node: store keys, create pool
+ * of threads, initialize each one.
+ *
+ * Each thread has unique ID, but 0 and 1 are reserved for receiving and accepting
+ * threads (if export node), so IDs could start from 2, but starting them
+ * from 10 allows easily understand what this thread is for.
+ */
+int dst_node_crypto_init(struct dst_node *n, struct dst_crypto_ctl *ctl)
+{
+ void *key = (ctl + 1);
+ int err = -ENOMEM, i;
+ char name[32];
+
+ if (ctl->hash_keysize) {
+ n->hash_key = kmalloc(ctl->hash_keysize, GFP_KERNEL);
+ if (!n->hash_key)
+ goto err_out_exit;
+ memcpy(n->hash_key, key, ctl->hash_keysize);
+ }
+
+ if (ctl->cipher_keysize) {
+ n->cipher_key = kmalloc(ctl->cipher_keysize, GFP_KERNEL);
+ if (!n->cipher_key)
+ goto err_out_free_hash;
+ memcpy(n->cipher_key, key, ctl->cipher_keysize);
+ }
+ memcpy(&n->crypto, ctl, sizeof(struct dst_crypto_ctl));
+
+ for (i=0; i<ctl->thread_num; ++i) {
+ snprintf(name, sizeof(name), "%s-crypto-%d", n->name, i);
+ /* Unique ids... */
+ err = thread_pool_add_worker(n->pool, name, i+10,
+ dst_crypto_thread_init, dst_crypto_thread_cleanup, n);
+ if (err)
+ goto err_out_free_threads;
+ }
+
+ return 0;
+
+err_out_free_threads:
+ while (--i >= 0)
+ thread_pool_del_worker_id(n->pool, i+10);
+
+ if (ctl->cipher_keysize)
+ kfree(n->cipher_key);
+ ctl->cipher_keysize = 0;
+err_out_free_hash:
+ if (ctl->hash_keysize)
+ kfree(n->hash_key);
+ ctl->hash_keysize = 0;
+err_out_exit:
+ return err;
+}
+
+void dst_node_crypto_exit(struct dst_node *n)
+{
+ struct dst_crypto_ctl *ctl = &n->crypto;
+
+ if (ctl->cipher_algo[0] || ctl->hash_algo[0]) {
+ kfree(n->hash_key);
+ kfree(n->cipher_key);
+ }
+}
+
+/*
+ * Thrad pool setup callback. Just stores a transaction in private data.
+ */
+static int dst_trans_crypto_setup(void *crypto_engine, void *trans)
+{
+ struct dst_crypto_engine *e = crypto_engine;
+
+ e->private = trans;
+ return 0;
+}
+
+#if 0
+static void dst_dump_bio(struct bio *bio)
+{
+ u8 *p;
+ struct bio_vec *bv;
+ int i;
+
+ bio_for_each_segment(bv, bio, i) {
+ dprintk("%s: %llu/%u: size: %u, offset: %u, data: ",
+ __func__, bio->bi_sector, bio->bi_size,
+ bv->bv_len, bv->bv_offset);
+
+ p = kmap(bv->bv_page) + bv->bv_offset;
+ for (i=0; i<bv->bv_len; ++i)
+ printk("%02x ", p[i]);
+ kunmap(bv->bv_page);
+ printk("\n");
+ }
+}
+#endif
+
+/*
+ * Encrypt/hash data and send it to the network.
+ */
+static int dst_crypto_process_sending(struct dst_crypto_engine *e,
+ struct bio *bio, u8 *hash)
+{
+ int err;
+
+ if (e->cipher) {
+ err = dst_crypt(e, bio);
+ if (err)
+ goto err_out_exit;
+ }
+
+ if (e->hash) {
+ err = dst_hash(e, bio, hash);
+ if (err)
+ goto err_out_exit;
+
+#ifdef CONFIG_DST_DEBUG
+ {
+ unsigned int i;
+
+ /* dst_dump_bio(bio); */
+
+ printk(KERN_DEBUG "%s: bio: %llu/%u, rw: %lu, hash: ",
+ __func__, (u64)bio->bi_sector,
+ bio->bi_size, bio_data_dir(bio));
+ for (i=0; i<crypto_hash_digestsize(e->hash); ++i)
+ printk("%02x ", hash[i]);
+ printk("\n");
+ }
+#endif
+ }
+
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+/*
+ * Check if received data is valid. Decipher if it is.
+ */
+static int dst_crypto_process_receiving(struct dst_crypto_engine *e,
+ struct bio *bio, u8 *hash, u8 *recv_hash)
+{
+ int err;
+
+ if (e->hash) {
+ int mismatch;
+
+ err = dst_hash(e, bio, hash);
+ if (err)
+ goto err_out_exit;
+
+ mismatch = !!memcmp(recv_hash, hash,
+ crypto_hash_digestsize(e->hash));
+#ifdef CONFIG_DST_DEBUG
+ /* dst_dump_bio(bio); */
+
+ printk(KERN_DEBUG "%s: bio: %llu/%u, rw: %lu, hash mismatch: %d",
+ __func__, (u64)bio->bi_sector, bio->bi_size,
+ bio_data_dir(bio), mismatch);
+ if (mismatch) {
+ unsigned int i;
+
+ printk(", recv/calc: ");
+ for (i=0; i<crypto_hash_digestsize(e->hash); ++i) {
+ printk("%02x/%02x ", recv_hash[i], hash[i]);
+ }
+ }
+ printk("\n");
+#endif
+ err = -1;
+ if (mismatch)
+ goto err_out_exit;
+ }
+
+ if (e->cipher) {
+ err = dst_crypt(e, bio);
+ if (err)
+ goto err_out_exit;
+ }
+
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+/*
+ * Thread pool callback to encrypt data and send it to the netowork.
+ */
+static int dst_trans_crypto_action(void *crypto_engine, void *schedule_data)
+{
+ struct dst_crypto_engine *e = crypto_engine;
+ struct dst_trans *t = schedule_data;
+ struct bio *bio = t->bio;
+ int err;
+
+ dprintk("%s: t: %p, gen: %llu, cipher: %p, hash: %p.\n",
+ __func__, t, t->gen, e->cipher, e->hash);
+
+ e->enc = t->enc;
+ e->iv = dst_gen_iv(t);
+
+ if (bio_data_dir(bio) == WRITE) {
+ err = dst_crypto_process_sending(e, bio, t->cmd.hash);
+ if (err)
+ goto err_out_exit;
+
+ if (e->hash) {
+ t->cmd.csize = crypto_hash_digestsize(e->hash);
+ t->cmd.size += t->cmd.csize;
+ }
+
+ return dst_trans_send(t);
+ } else {
+ u8 *hash = e->data + e->size/2;
+
+ err = dst_crypto_process_receiving(e, bio, hash, t->cmd.hash);
+ if (err)
+ goto err_out_exit;
+
+ dst_trans_remove(t);
+ dst_trans_put(t);
+ }
+
+ return 0;
+
+err_out_exit:
+ t->error = err;
+ dst_trans_put(t);
+ return err;
+}
+
+/*
+ * Schedule crypto processing for given transaction.
+ */
+int dst_trans_crypto(struct dst_trans *t)
+{
+ struct dst_node *n = t->n;
+ int err;
+
+ err = thread_pool_schedule(n->pool,
+ dst_trans_crypto_setup, dst_trans_crypto_action,
+ t, MAX_SCHEDULE_TIMEOUT);
+ if (err)
+ goto err_out_exit;
+
+ return 0;
+
+err_out_exit:
+ dst_trans_put(t);
+ return err;
+}
+
+/*
+ * Crypto machinery for the export node.
+ */
+static int dst_export_crypto_setup(void *crypto_engine, void *bio)
+{
+ struct dst_crypto_engine *e = crypto_engine;
+
+ e->private = bio;
+ return 0;
+}
+
+static int dst_export_crypto_action(void *crypto_engine, void *schedule_data)
+{
+ struct dst_crypto_engine *e = crypto_engine;
+ struct bio *bio = schedule_data;
+ struct dst_export_priv *p = bio->bi_private;
+ int err;
+
+ dprintk("%s: e: %p, data: %p, bio: %llu/%u, dir: %lu.\n", __func__,
+ e, e->data, (u64)bio->bi_sector, bio->bi_size, bio_data_dir(bio));
+
+ e->enc = (bio_data_dir(bio) == READ);
+ e->iv = p->cmd.id;
+
+ if (bio_data_dir(bio) == WRITE) {
+ u8 *hash = e->data + e->size/2;
+
+ err = dst_crypto_process_receiving(e, bio, hash, p->cmd.hash);
+ if (err)
+ goto err_out_exit;
+
+ generic_make_request(bio);
+ } else {
+ err = dst_crypto_process_sending(e, bio, p->cmd.hash);
+ if (err)
+ goto err_out_exit;
+
+ if (e->hash) {
+ p->cmd.csize = crypto_hash_digestsize(e->hash);
+ p->cmd.size += p->cmd.csize;
+ }
+
+ err = dst_export_send_bio(bio);
+ }
+ return 0;
+
+err_out_exit:
+ bio_put(bio);
+ return err;
+}
+
+int dst_export_crypto(struct dst_node *n, struct bio *bio)
+{
+ int err;
+
+ err = thread_pool_schedule(n->pool,
+ dst_export_crypto_setup, dst_export_crypto_action,
+ bio, MAX_SCHEDULE_TIMEOUT);
+ if (err)
+ goto err_out_exit;
+
+ return 0;
+
+err_out_exit:
+ bio_put(bio);
+ return err;
+}
Each DST device contains of two nodes: local and remote (called also as export node).
This patch contains local node processing engine: network state storage,
socket processing loops and state machine, socket polling machinery, reconnection
logic, send/receive basic helpers, related IO commands and so on.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/state.c b/drivers/staging/dst/state.c
new file mode 100644
index 0000000..7243d37
--- /dev/null
+++ b/drivers/staging/dst/state.c
@@ -0,0 +1,839 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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/buffer_head.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/connector.h>
+#include <linux/dst.h>
+#include <linux/device.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/socket.h>
+#include <linux/slab.h>
+
+#include <net/sock.h>
+
+/*
+ * Polling machinery.
+ */
+
+struct dst_poll_helper
+{
+ poll_table pt;
+ struct dst_state *st;
+};
+
+static int dst_queue_wake(wait_queue_t *wait, unsigned mode, int sync, void *key)
+{
+ struct dst_state *st = container_of(wait, struct dst_state, wait);
+
+ wake_up(&st->thread_wait);
+ return 1;
+}
+
+static void dst_queue_func(struct file *file, wait_queue_head_t *whead,
+ poll_table *pt)
+{
+ struct dst_state *st = container_of(pt, struct dst_poll_helper, pt)->st;
+
+ st->whead = whead;
+ init_waitqueue_func_entry(&st->wait, dst_queue_wake);
+ add_wait_queue(whead, &st->wait);
+}
+
+void dst_poll_exit(struct dst_state *st)
+{
+ if (st->whead) {
+ remove_wait_queue(st->whead, &st->wait);
+ st->whead = NULL;
+ }
+}
+
+int dst_poll_init(struct dst_state *st)
+{
+ struct dst_poll_helper ph;
+
+ ph.st = st;
+ init_poll_funcptr(&ph.pt, &dst_queue_func);
+
+ st->socket->ops->poll(NULL, st->socket, &ph.pt);
+ return 0;
+}
+
+/*
+ * Header receiving function - may block.
+ */
+static int dst_data_recv_header(struct socket *sock,
+ void *data, unsigned int size, int block)
+{
+ struct msghdr msg;
+ struct kvec iov;
+ int err;
+
+ iov.iov_base = data;
+ 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 = (block)?MSG_WAITALL:MSG_DONTWAIT;
+
+ err = kernel_recvmsg(sock, &msg, &iov, 1, iov.iov_len,
+ msg.msg_flags);
+ if (err != size)
+ return -1;
+
+ return 0;
+}
+
+/*
+ * Header sending function - may block.
+ */
+int dst_data_send_header(struct socket *sock,
+ void *data, unsigned int size, int more)
+{
+ struct msghdr msg;
+ struct kvec iov;
+ int err;
+
+ iov.iov_base = data;
+ 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_WAITALL | (more)?MSG_MORE:0;
+
+ err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
+ if (err != size) {
+ dprintk("%s: size: %u, more: %d, err: %d.\n",
+ __func__, size, more, err);
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Block autoconfiguration: request size of the storage and permissions.
+ */
+static int dst_request_remote_config(struct dst_state *st)
+{
+ struct dst_node *n = st->node;
+ int err = -EINVAL;
+ struct dst_cmd *cmd = st->data;
+
+ memset(cmd, 0, sizeof(struct dst_cmd));
+ cmd->cmd = DST_CFG;
+
+ dst_convert_cmd(cmd);
+
+ err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
+ if (err)
+ goto out;
+
+ err = dst_data_recv_header(st->socket, cmd, sizeof(struct dst_cmd), 1);
+ if (err)
+ goto out;
+
+ dst_convert_cmd(cmd);
+
+ if (cmd->cmd != DST_CFG) {
+ err = -EINVAL;
+ dprintk("%s: checking result: cmd: %d, size reported: %llu.\n",
+ __func__, cmd->cmd, cmd->sector);
+ goto out;
+ }
+
+ if (n->size != 0)
+ n->size = min_t(loff_t, n->size, cmd->sector);
+ else
+ n->size = cmd->sector;
+
+ n->info->size = n->size;
+ st->permissions = cmd->rw;
+
+out:
+ dprintk("%s: n: %p, err: %d, size: %llu, permission: %x.\n",
+ __func__, n, err, n->size, st->permissions);
+ return err;
+}
+
+/*
+ * Socket machinery.
+ */
+
+#define DST_DEFAULT_TIMEO 20000
+
+int dst_state_socket_create(struct dst_state *st)
+{
+ int err;
+ struct socket *sock;
+ struct dst_network_ctl *ctl = &st->ctl;
+
+ err = sock_create(ctl->addr.sa_family, ctl->type, ctl->proto, &sock);
+ if (err < 0)
+ return err;
+
+ sock->sk->sk_sndtimeo = sock->sk->sk_rcvtimeo =
+ msecs_to_jiffies(DST_DEFAULT_TIMEO);
+ sock->sk->sk_allocation = GFP_NOIO;
+
+ st->socket = st->read_socket = sock;
+ return 0;
+}
+
+void dst_state_socket_release(struct dst_state *st)
+{
+ dprintk("%s: st: %p, socket: %p, n: %p.\n",
+ __func__, st, st->socket, st->node);
+ if (st->socket) {
+ sock_release(st->socket);
+ st->socket = NULL;
+ st->read_socket = NULL;
+ }
+}
+
+void dst_dump_addr(struct socket *sk, struct sockaddr *sa, char *str)
+{
+ if (sk->ops->family == AF_INET) {
+ struct sockaddr_in *sin = (struct sockaddr_in *)sa;
+ printk(KERN_INFO "%s %u.%u.%u.%u:%d.\n",
+ str, NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port));
+ } else if (sk->ops->family == AF_INET6) {
+ struct sockaddr_in6 *sin = (struct sockaddr_in6 *)sa;
+ printk(KERN_INFO "%s %pi6:%d",
+ str, &sin->sin6_addr, ntohs(sin->sin6_port));
+ }
+}
+
+void dst_state_exit_connected(struct dst_state *st)
+{
+ if (st->socket) {
+ dst_poll_exit(st);
+ st->socket->ops->shutdown(st->socket, 2);
+
+ dst_dump_addr(st->socket, (struct sockaddr *)&st->ctl.addr,
+ "Disconnected peer");
+ dst_state_socket_release(st);
+ }
+}
+
+static int dst_state_init_connected(struct dst_state *st)
+{
+ int err;
+ struct dst_network_ctl *ctl = &st->ctl;
+
+ err = dst_state_socket_create(st);
+ if (err)
+ goto err_out_exit;
+
+ err = kernel_connect(st->socket, (struct sockaddr *)&st->ctl.addr,
+ st->ctl.addr.sa_data_len, 0);
+ if (err)
+ goto err_out_release;
+
+ err = dst_poll_init(st);
+ if (err)
+ goto err_out_release;
+
+ dst_dump_addr(st->socket, (struct sockaddr *)&ctl->addr,
+ "Connected to peer");
+
+ return 0;
+
+err_out_release:
+ dst_state_socket_release(st);
+err_out_exit:
+ return err;
+}
+
+/*
+ * State reset is used to reconnect to the remote peer.
+ * May fail, but who cares, we will try again later.
+ */
+static void inline dst_state_reset_nolock(struct dst_state *st)
+{
+ dst_state_exit_connected(st);
+ dst_state_init_connected(st);
+}
+
+static void inline dst_state_reset(struct dst_state *st)
+{
+ dst_state_lock(st);
+ dst_state_reset_nolock(st);
+ dst_state_unlock(st);
+}
+
+/*
+ * Basic network sending/receiving functions.
+ * Blocked mode is used.
+ */
+static int dst_data_recv_raw(struct dst_state *st, void *buf, u64 size)
+{
+ struct msghdr msg;
+ struct kvec iov;
+ int err;
+
+ BUG_ON(!size);
+
+ iov.iov_base = buf;
+ 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;
+
+ err = kernel_recvmsg(st->socket, &msg, &iov, 1, iov.iov_len,
+ msg.msg_flags);
+ if (err <= 0) {
+ dprintk("%s: failed to recv data: size: %llu, err: %d.\n",
+ __func__, size, err);
+ if (err == 0)
+ err = -ECONNRESET;
+
+ dst_state_exit_connected(st);
+ }
+
+ return err;
+}
+
+/*
+ * Ping command to early detect failed nodes.
+ */
+static int dst_send_ping(struct dst_state *st)
+{
+ struct dst_cmd *cmd = st->data;
+ int err = -ECONNRESET;
+
+ dst_state_lock(st);
+ if (st->socket) {
+ memset(cmd, 0, sizeof(struct dst_cmd));
+
+ cmd->cmd = __cpu_to_be32(DST_PING);
+
+ err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
+ }
+ dprintk("%s: st: %p, socket: %p, err: %d.\n", __func__, st, st->socket, err);
+ dst_state_unlock(st);
+
+ return err;
+}
+
+/*
+ * Receiving function, which should either return error or read
+ * whole block request. If there was no traffic for a one second,
+ * send a ping, since remote node may die.
+ */
+int dst_data_recv(struct dst_state *st, void *data, unsigned int size)
+{
+ unsigned int revents = 0;
+ unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP;
+ unsigned int mask = err_mask | POLLIN;
+ struct dst_node *n = st->node;
+ int err = 0;
+
+ while (size && !err) {
+ revents = dst_state_poll(st);
+
+ if (!(revents & mask)) {
+ DEFINE_WAIT(wait);
+
+ for (;;) {
+ prepare_to_wait(&st->thread_wait, &wait,
+ TASK_INTERRUPTIBLE);
+ if (!n->trans_scan_timeout || st->need_exit)
+ break;
+
+ revents = dst_state_poll(st);
+
+ if (revents & mask)
+ break;
+
+ if (signal_pending(current))
+ break;
+
+ if (!schedule_timeout(HZ)) {
+ err = dst_send_ping(st);
+ if (err)
+ return err;
+ }
+
+ continue;
+ }
+ finish_wait(&st->thread_wait, &wait);
+ }
+
+ err = -ECONNRESET;
+ dst_state_lock(st);
+
+ if ( st->socket &&
+ (st->read_socket == st->socket) &&
+ (revents & POLLIN)) {
+ err = dst_data_recv_raw(st, data, size);
+ if (err > 0) {
+ data += err;
+ size -= err;
+ err = 0;
+ }
+ }
+
+ if (revents & err_mask || !st->socket) {
+ dprintk("%s: revents: %x, socket: %p, size: %u, err: %d.\n",
+ __func__, revents, st->socket, size, err);
+ err = -ECONNRESET;
+ }
+
+ dst_state_unlock(st);
+
+ if (!n->trans_scan_timeout)
+ err = -ENODEV;
+ }
+
+ return err;
+}
+
+/*
+ * Send block autoconf reply.
+ */
+static int dst_process_cfg(struct dst_state *st)
+{
+ struct dst_node *n = st->node;
+ struct dst_cmd *cmd = st->data;
+ int err;
+
+ cmd->sector = n->size;
+ cmd->rw = st->permissions;
+
+ dst_convert_cmd(cmd);
+
+ dst_state_lock(st);
+ err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0);
+ dst_state_unlock(st);
+
+ return err;
+}
+
+/*
+ * Receive block IO from the network.
+ */
+static int dst_recv_bio(struct dst_state *st, struct bio *bio, unsigned int total_size)
+{
+ struct bio_vec *bv;
+ int i, err;
+ void *data;
+ unsigned int sz;
+
+ bio_for_each_segment(bv, bio, i) {
+ sz = min(total_size, bv->bv_len);
+
+ dprintk("%s: bio: %llu/%u, total: %u, len: %u, sz: %u, off: %u.\n",
+ __func__, (u64)bio->bi_sector, bio->bi_size, total_size,
+ bv->bv_len, sz, bv->bv_offset);
+
+ data = kmap(bv->bv_page) + bv->bv_offset;
+ err = dst_data_recv(st, data, sz);
+ kunmap(bv->bv_page);
+
+ bv->bv_len = sz;
+
+ if (err)
+ return err;
+
+ total_size -= sz;
+ if (total_size == 0)
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * Our block IO has just completed and arrived: get it.
+ */
+static int dst_process_io_response(struct dst_state *st)
+{
+ struct dst_node *n = st->node;
+ struct dst_cmd *cmd = st->data;
+ struct dst_trans *t;
+ int err = 0;
+ struct bio *bio;
+
+ mutex_lock(&n->trans_lock);
+ t = dst_trans_search(n, cmd->id);
+ mutex_unlock(&n->trans_lock);
+
+ if (!t)
+ goto err_out_exit;
+
+ bio = t->bio;
+
+ dprintk("%s: bio: %llu/%u, cmd_size: %u, csize: %u, dir: %lu.\n",
+ __func__, (u64)bio->bi_sector, bio->bi_size, cmd->size,
+ cmd->csize, bio_data_dir(bio));
+
+ if (bio_data_dir(bio) == READ) {
+ if (bio->bi_size != cmd->size - cmd->csize)
+ goto err_out_exit;
+
+ if (dst_need_crypto(n)) {
+ err = dst_recv_cdata(st, t->cmd.hash);
+ if (err)
+ goto err_out_exit;
+ }
+
+ err = dst_recv_bio(st, t->bio, bio->bi_size);
+ if (err)
+ goto err_out_exit;
+
+ if (dst_need_crypto(n))
+ return dst_trans_crypto(t);
+ } else {
+ err = -EBADMSG;
+ if (cmd->size || cmd->csize)
+ goto err_out_exit;
+ }
+
+ dst_trans_remove(t);
+ dst_trans_put(t);
+
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+/*
+ * Receive crypto data.
+ */
+int dst_recv_cdata(struct dst_state *st, void *cdata)
+{
+ struct dst_cmd *cmd = st->data;
+ struct dst_node *n = st->node;
+ struct dst_crypto_ctl *c = &n->crypto;
+ int err;
+
+ if (cmd->csize != c->crypto_attached_size) {
+ dprintk("%s: cmd: cmd: %u, sector: %llu, size: %u, "
+ "csize: %u != digest size %u.\n",
+ __func__, cmd->cmd, cmd->sector, cmd->size,
+ cmd->csize, c->crypto_attached_size);
+ err = -EINVAL;
+ goto err_out_exit;
+ }
+
+ err = dst_data_recv(st, cdata, cmd->csize);
+ if (err)
+ goto err_out_exit;
+
+ cmd->size -= cmd->csize;
+ return 0;
+
+err_out_exit:
+ return err;
+}
+
+/*
+ * Receive the command and start its processing.
+ */
+static int dst_recv_processing(struct dst_state *st)
+{
+ int err = -EINTR;
+ struct dst_cmd *cmd = st->data;
+
+ /*
+ * If socket will be reset after this statement, then
+ * dst_data_recv() will just fail and loop will
+ * start again, so it can be done without any locks.
+ *
+ * st->read_socket is needed to prevents state machine
+ * breaking between this data reading and subsequent one
+ * in protocol specific functions during connection reset.
+ * In case of reset we have to read next command and do
+ * not expect data for old command to magically appear in
+ * new connection.
+ */
+ st->read_socket = st->socket;
+ err = dst_data_recv(st, cmd, sizeof(struct dst_cmd));
+ if (err)
+ goto out_exit;
+
+ dst_convert_cmd(cmd);
+
+ dprintk("%s: cmd: %u, size: %u, csize: %u, id: %llu, "
+ "sector: %llu, flags: %llx, rw: %llx.\n",
+ __func__, cmd->cmd, cmd->size,
+ cmd->csize, cmd->id, cmd->sector,
+ cmd->flags, cmd->rw);
+
+ /*
+ * This should catch protocol breakage and random garbage instead of commands.
+ */
+ if (unlikely(cmd->csize > st->size - sizeof(struct dst_cmd))) {
+ err = -EBADMSG;
+ goto out_exit;
+ }
+
+ err = -EPROTO;
+ switch (cmd->cmd) {
+ case DST_IO_RESPONSE:
+ err = dst_process_io_response(st);
+ break;
+ case DST_IO:
+ err = dst_process_io(st);
+ break;
+ case DST_CFG:
+ err = dst_process_cfg(st);
+ break;
+ case DST_PING:
+ err = 0;
+ break;
+ default:
+ break;
+ }
+
+out_exit:
+ return err;
+}
+
+/*
+ * Receiving thread. For the client node we should try to reconnect,
+ * for accepted client we just drop the state and expect it to reconnect.
+ */
+static int dst_recv(void *init_data, void *schedule_data)
+{
+ struct dst_state *st = schedule_data;
+ struct dst_node *n = init_data;
+ int err = 0;
+
+ dprintk("%s: start st: %p, n: %p, scan: %lu, need_exit: %d.\n",
+ __func__, st, n, n->trans_scan_timeout, st->need_exit);
+
+ while (n->trans_scan_timeout && !st->need_exit) {
+ err = dst_recv_processing(st);
+ if (err < 0) {
+ if (!st->ctl.type)
+ break;
+
+ if (!n->trans_scan_timeout || st->need_exit)
+ break;
+
+ dst_state_reset(st);
+ msleep(1000);
+ }
+ }
+
+ st->need_exit = 1;
+ wake_up(&st->thread_wait);
+
+ dprintk("%s: freeing receiving socket st: %p.\n", __func__, st);
+ dst_state_lock(st);
+ dst_state_exit_connected(st);
+ dst_state_unlock(st);
+ dst_state_put(st);
+
+ dprintk("%s: freed receiving socket st: %p.\n", __func__, st);
+
+ return err;
+}
+
+/*
+ * Network state dies here and borns couple of lines below.
+ * This object is the main network state processing engine:
+ * sending, receiving, reconnections, all network related
+ * tasks are handled on behalf of the state.
+ */
+static void dst_state_free(struct dst_state *st)
+{
+ dprintk("%s: st: %p.\n", __func__, st);
+ if (st->cleanup)
+ st->cleanup(st);
+ kfree(st->data);
+ kfree(st);
+}
+
+struct dst_state *dst_state_alloc(struct dst_node *n)
+{
+ struct dst_state *st;
+ int err = -ENOMEM;
+
+ st = kzalloc(sizeof(struct dst_state), GFP_KERNEL);
+ if (!st)
+ goto err_out_exit;
+
+ st->node = n;
+ st->need_exit = 0;
+
+ st->size = PAGE_SIZE;
+ st->data = kmalloc(st->size, GFP_KERNEL);
+ if (!st->data)
+ goto err_out_free;
+
+ spin_lock_init(&st->request_lock);
+ INIT_LIST_HEAD(&st->request_list);
+
+ mutex_init(&st->state_lock);
+ init_waitqueue_head(&st->thread_wait);
+
+ /*
+ * One for processing thread, another one for node itself.
+ */
+ atomic_set(&st->refcnt, 2);
+
+ dprintk("%s: st: %p, n: %p.\n", __func__, st, st->node);
+
+ return st;
+
+err_out_free:
+ kfree(st);
+err_out_exit:
+ return ERR_PTR(err);
+}
+
+int dst_state_schedule_receiver(struct dst_state *st)
+{
+ return thread_pool_schedule_private(st->node->pool, dst_thread_setup,
+ dst_recv, st, MAX_SCHEDULE_TIMEOUT, st->node);
+}
+
+/*
+ * Initialize client's connection to the remote peer: allocate state,
+ * connect and perform block IO autoconfiguration.
+ */
+int dst_node_init_connected(struct dst_node *n, struct dst_network_ctl *r)
+{
+ struct dst_state *st;
+ int err = -ENOMEM;
+
+ st = dst_state_alloc(n);
+ if (IS_ERR(st)) {
+ err = PTR_ERR(st);
+ goto err_out_exit;
+ }
+ memcpy(&st->ctl, r, sizeof(struct dst_network_ctl));
+
+ err = dst_state_init_connected(st);
+ if (err)
+ goto err_out_free_data;
+
+ err = dst_request_remote_config(st);
+ if (err)
+ goto err_out_exit_connected;
+ n->state = st;
+
+ err = dst_state_schedule_receiver(st);
+ if (err)
+ goto err_out_exit_connected;
+
+ return 0;
+
+err_out_exit_connected:
+ dst_state_exit_connected(st);
+err_out_free_data:
+ dst_state_free(st);
+err_out_exit:
+ n->state = NULL;
+ return err;
+}
+
+void dst_state_put(struct dst_state *st)
+{
+ dprintk("%s: st: %p, refcnt: %d.\n",
+ __func__, st, atomic_read(&st->refcnt));
+ if (atomic_dec_and_test(&st->refcnt))
+ dst_state_free(st);
+}
+
+/*
+ * Send block IO to the network one by one using zero-copy ->sendpage().
+ */
+int dst_send_bio(struct dst_state *st, struct dst_cmd *cmd, struct bio *bio)
+{
+ struct bio_vec *bv;
+ struct dst_crypto_ctl *c = &st->node->crypto;
+ int err, i = 0;
+ int flags = MSG_WAITALL;
+
+ err = dst_data_send_header(st->socket, cmd,
+ sizeof(struct dst_cmd) + c->crypto_attached_size, bio->bi_vcnt);
+ if (err)
+ goto err_out_exit;
+
+ bio_for_each_segment(bv, bio, i) {
+ if (i < bio->bi_vcnt - 1)
+ flags |= MSG_MORE;
+
+ err = kernel_sendpage(st->socket, bv->bv_page, bv->bv_offset,
+ bv->bv_len, flags);
+ if (err <= 0)
+ goto err_out_exit;
+ }
+
+ return 0;
+
+err_out_exit:
+ dprintk("%s: %d/%d, flags: %x, err: %d.\n",
+ __func__, i, bio->bi_vcnt, flags, err);
+ return err;
+}
+
+/*
+ * Send transaction to the remote peer.
+ */
+int dst_trans_send(struct dst_trans *t)
+{
+ int err;
+ struct dst_state *st = t->n->state;
+ struct bio *bio = t->bio;
+
+ dst_convert_cmd(&t->cmd);
+
+ dst_state_lock(st);
+ if (!st->socket) {
+ err = dst_state_init_connected(st);
+ if (err)
+ goto err_out_unlock;
+ }
+
+ if (bio_data_dir(bio) == WRITE) {
+ err = dst_send_bio(st, &t->cmd, t->bio);
+ } else {
+ err = dst_data_send_header(st->socket, &t->cmd,
+ sizeof(struct dst_cmd), 0);
+ }
+ if (err)
+ goto err_out_reset;
+
+ dst_state_unlock(st);
+ return 0;
+
+err_out_reset:
+ dst_state_reset_nolock(st);
+err_out_unlock:
+ dst_state_unlock(st);
+
+ return err;
+}
This patch contains DST core files, which introduce
block layer, connector and sysfs registration glue and main headers.
Connector is used for the configuration of the node (its type, address,
device name and so on). Sysfs provides bits of information about running
devices in the following format:
+/*
+ * 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
+ */
DST header contains structure definitions and protocol command description.
Signed-off-by: Evgeniy Polyakov <[email protected]>
diff --git a/drivers/staging/dst/dcore.c b/drivers/staging/dst/dcore.c
new file mode 100644
index 0000000..82aa9c2
--- /dev/null
+++ b/drivers/staging/dst/dcore.c
@@ -0,0 +1,972 @@
+/*
+ * 2007+ Copyright (c) Evgeniy Polyakov <[email protected]>
+ * 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[] = "Dementianting goldfish";
+
+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 block_device *bdev, fmode_t mode)
+{
+ struct dst_node *n = bdev->bd_disk->private_data;
+
+ dst_node_get(n);
+ return 0;
+}
+
+static int dst_bdev_release(struct gendisk *disk, fmode_t mode)
+{
+ struct dst_node *n = 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_init_queue(NULL, NULL);
+ 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,
+ "%pi6:%d\n",
+ &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, FMODE_READ|FMODE_WRITE);
+ }
+
+ 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, FMODE_READ|FMODE_WRITE);
+ 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 <[email protected]>");
+MODULE_LICENSE("GPL");
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 <[email protected]>
+ * 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 */
Signed-off-by: Evgeniy Polaykov <[email protected]>
index 0000000..12ffa37
--- /dev/null
+++ b/drivers/staging/dst/Kconfig
@@ -0,0 +1,71 @@
+config DST
+ tristate "Distributed storage"
+ depends on NET && CRYPTO && SYSFS
+ select CONNECTOR
+ select LIBCRC32C
+ ---help---
+ DST is a network block device storage, which can be used to organize
+ exported storages on the remote nodes into the local block device.
+
+ DST is a network block device storage, which can be used to organize
+ exported storages on the remote nodes into the local block device.
+
+ DST works on top of any network media and protocol, it is just a matter
+ of configuration utility to understand the correct addresses. The most
+ common example is TCP over IP allows to pass through firewalls and
+ created remote backup storage in the different datacenter. DST requires
+ single port to be enabled on the exporting node and outgoing connections
+ on the local node.
+
+ DST works with in-kernel client and server, which improves the performance
+ eliminating unneded data copies and allows not to depend on the version
+ of the external IO components. It requires userspace configuration utility
+ though.
+
+ DST uses transaction model, when each store has to be explicitly acked
+ from the remote node to be considered as successfully written. There
+ may be lots of in-flight transactions. When remote host does not ack
+ the transaction it will be resent predefined number of times with specified
+ timeouts between them. All those parameters are configurable. Transactions
+ are marked as failed after all resends completed unsuccessfully, having
+ long enough resend timeout and/or large number of resends allows not to
+ return error to the higher (FS usually) layer in case of short network
+ problems or remote node outages. In case of network RAID setup this means
+ that storage will not degrade until transactions are marked as failed, and
+ thus will not force checksum recalculation and data rebuild. In case of
+ connection failure DST will try to reconnect to the remote node automatically.
+ DST sends ping commands at idle time to detect if remote node is alive.
+
+ Because of transactional model it is possible to use zero-copy sending
+ without worry of data corruption (which in turn could be detected by the
+ strong checksums though).
+
+ DST may fully encrypt the data channel in case of untrusted channel and implement
+ strong checksum of the transferred data. It is possible to configure algorithms
+ and crypto keys, they should match on both sides of the network channel.
+ Crypto processing does not introduce noticeble performance overhead, since DST
+ uses configurable pool of threads to perform crypto processing.
+
+ DST utilizes memory pool model of all its transaction allocations (it is the
+ only additional allocation on the client) and server allocations (bio pools,
+ while pages are allocated from the slab).
+
+ At startup DST performs a simple negotiation with the export node to determine
+ access permissions and size of the exported storage. It can be extended if
+ new parameters should be autonegotiated.
+
+ DST carries block IO flags in the protocol, which allows to transparently implement
+ barriers and sync/flush operations. Those flags are used in the export node where
+ IO against the local storage is performed, which means that sync write will be sync
+ on the remote node too, which in turn improves data integrity and improved resistance
+ to errors and data corruption during power outages or storage damages.
+
+ Homepage: http://www.ioremap.net/projects/dst
+ Userspace configuration utility and the latest releases: http://www.ioremap.net/archive/dst/
+
+config DST_DEBUG
+ bool "DST debug"
+ depends on DST
+ ---help---
+ This option will turn HEAVY debugging of the DST.
+ Turn it on ONLY if you have to debug some really obscure problem.
diff --git a/drivers/staging/dst/Makefile b/drivers/staging/dst/Makefile
new file mode 100644
index 0000000..3a8b0cf
--- /dev/null
+++ b/drivers/staging/dst/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_DST) += nst.o
+
+nst-y := dcore.o state.o export.o thread_pool.o crypto.o trans.o
diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index ce6badd..9de9ad5 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -95,5 +95,7 @@ source "drivers/staging/epl/Kconfig"
source "drivers/staging/android/Kconfig"
+source "drivers/staging/dst/Kconfig"
+
endif # !STAGING_EXCLUDE_BUILD
endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index 9ddcc2b..14a89fa 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_INPUT_MIMIO) += mimio/
obj-$(CONFIG_TRANZPORT) += frontier/
obj-$(CONFIG_EPL) += epl/
obj-$(CONFIG_ANDROID) += android/
+obj-$(CONFIG_DST) += dst/
On Wed, Jan 14, 2009 at 02:05:26AM +0300, Evgeniy Polyakov wrote:
> Patches were split on per-file basis, so tree in the middle of the series will not
> compile, which should not be a problem, since kconfig/makefile changes are introduced
> in the latest patch.
Looks good to me, but do we need the "export these symbols" patch to get
this to work properly as well?
Also, can you send me a patch with a TODO file in the
drivers/staging/dst/ directory, detailing what needs to be done on it to
move it over to the main portion of the kernel?
thanks,
greg k-h
On Tue, Jan 13, 2009 at 03:39:32PM -0800, Greg KH ([email protected]) wrote:
> On Wed, Jan 14, 2009 at 02:05:26AM +0300, Evgeniy Polyakov wrote:
> > Patches were split on per-file basis, so tree in the middle of the series will not
> > compile, which should not be a problem, since kconfig/makefile changes are introduced
> > in the latest patch.
>
> Looks good to me, but do we need the "export these symbols" patch to get
> this to work properly as well?
No, exports are needed for POHMELFS which I'm waiting a reply from
Andrew or Linus.
> Also, can you send me a patch with a TODO file in the
> drivers/staging/dst/ directory, detailing what needs to be done on it to
> move it over to the main portion of the kernel?
Nothing :)
Really. I implemented all the suggestions I got from the previous
reviews (including spaces and documentations, which btw were the only
ones :) way too long ago and did not get any other complaints. Actually
the tree I sent to you does not contain documentation update I have in
the own tree (pointed during review), so this can be added as todo entry :)
My fault I found that too late.
--
Evgeniy Polyakov
On Wed, Jan 14, 2009 at 02:47:34AM +0300, Evgeniy Polyakov wrote:
> On Tue, Jan 13, 2009 at 03:39:32PM -0800, Greg KH ([email protected]) wrote:
> > On Wed, Jan 14, 2009 at 02:05:26AM +0300, Evgeniy Polyakov wrote:
> > > Patches were split on per-file basis, so tree in the middle of the series will not
> > > compile, which should not be a problem, since kconfig/makefile changes are introduced
> > > in the latest patch.
> >
> > Looks good to me, but do we need the "export these symbols" patch to get
> > this to work properly as well?
>
> No, exports are needed for POHMELFS which I'm waiting a reply from
> Andrew or Linus.
Ah, sorry, got the two confused :)
> > Also, can you send me a patch with a TODO file in the
> > drivers/staging/dst/ directory, detailing what needs to be done on it to
> > move it over to the main portion of the kernel?
>
> Nothing :)
Great!
> Really. I implemented all the suggestions I got from the previous
> reviews (including spaces and documentations, which btw were the only
> ones :) way too long ago and did not get any other complaints. Actually
> the tree I sent to you does not contain documentation update I have in
> the own tree (pointed during review), so this can be added as todo entry :)
> My fault I found that too late.
Hm, then why can't this whole thing just go into fs/dst/ right now?
It's self-contained, so there shouldn't be any special "must live in
staging" rule for filesystems before adding them.
We take new drivers at almost any point in the release cycle, why should
filesystems be any different?
Linus, Andrew, any objections?
thanks,
greg k-h
On Tue, Jan 13, 2009 at 04:01:30PM -0800, Greg KH ([email protected]) wrote:
> > Really. I implemented all the suggestions I got from the previous
> > reviews (including spaces and documentations, which btw were the only
> > ones :) way too long ago and did not get any other complaints. Actually
> > the tree I sent to you does not contain documentation update I have in
> > the own tree (pointed during review), so this can be added as todo entry :)
> > My fault I found that too late.
>
> Hm, then why can't this whole thing just go into fs/dst/ right now?
> It's self-contained, so there shouldn't be any special "must live in
> staging" rule for filesystems before adding them.
Its a block device not a filesystem, so it is more like a driver.
All original patches placed it into the drivers/block/dst without touch
any external files except makefile and kconfig.
> We take new drivers at almost any point in the release cycle, why should
> filesystems be any different?
I suppose this is a rethorical question, since there is no answer :)
> Linus, Andrew, any objections?
Hi there!
--
Evgeniy Polyakov
On Tue, 13 Jan 2009 16:01:30 -0800
Greg KH <[email protected]> wrote:
> > Really. I implemented all the suggestions I got from the previous
> > reviews (including spaces and documentations, which btw were the only
> > ones :) way too long ago and did not get any other complaints. Actually
> > the tree I sent to you does not contain documentation update I have in
> > the own tree (pointed during review), so this can be added as todo entry :)
> > My fault I found that too late.
>
> Hm, then why can't this whole thing just go into fs/dst/ right now?
> It's self-contained, so there shouldn't be any special "must live in
> staging" rule for filesystems before adding them.
>
> We take new drivers at almost any point in the release cycle, why should
> filesystems be any different?
Well... the case for merging drivers is usually pretty simple - the
hardware exists, so we need the driver.
Whereas the "do we need this" case for new filesystems isn't this simple.
On Tue, Jan 13, 2009 at 04:12:21PM -0800, Andrew Morton ([email protected]) wrote:
> > Hm, then why can't this whole thing just go into fs/dst/ right now?
> > It's self-contained, so there shouldn't be any special "must live in
> > staging" rule for filesystems before adding them.
> >
> > We take new drivers at almost any point in the release cycle, why should
> > filesystems be any different?
>
> Well... the case for merging drivers is usually pretty simple - the
> hardware exists, so we need the driver.
>
> Whereas the "do we need this" case for new filesystems isn't this simple.
More on this, it is a block device which does not work with hardware.
And yes, question is serious. And you may not believe, but it is not me
to answer this. I'm happy to provide any needed information.
In a nutshell, it is a network block device on really huge steroids.
--
Evgeniy Polyakov
On Wed, Jan 14, 2009 at 03:15:46AM +0300, Evgeniy Polyakov ([email protected]) wrote:
> > Whereas the "do we need this" case for new filesystems isn't this simple.
>
> More on this, it is a block device which does not work with hardware.
> And yes, question is serious. And you may not believe, but it is not me
> to answer this. I'm happy to provide any needed information.
> In a nutshell, it is a network block device on really huge steroids.
And according to POHMELFS which is a parallel very high-performance
(forget nfs) network filesystem with coherent local cache of data
and metadata.
The only change expected to be done is one additional network command
to parse the data currently sent via netlink. We want to connect to the
new servers by another server request and not by admin steps.
Patch will be somewhat 10-50 lines. And while you at it, please shed a
light on this exports for POHMELFS:
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -513,6 +513,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
}
return ret;
}
+EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
#ifdef CONFIG_NUMA
struct page *__page_cache_alloc(gfp_t gfp)
@@ -627,6 +628,7 @@ int __lock_page_killable(struct page *page)
return __wait_on_bit_lock(page_waitqueue(page), &wait,
sync_page_killable, TASK_KILLABLE);
}
+EXPORT_SYMBOL_GPL(__lock_page_killable);
/**
* __lock_page_nosync - get a lock on the page, without calling sync_page()
--
Evgeniy Polyakov
On Wed, 14 Jan 2009 03:20:08 +0300
Evgeniy Polyakov <[email protected]> wrote:
> And while you at it, please shed a
> light on this exports for POHMELFS:
>
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -513,6 +513,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
> }
> return ret;
> }
> +EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
OK by me.
> #ifdef CONFIG_NUMA
> struct page *__page_cache_alloc(gfp_t gfp)
> @@ -627,6 +628,7 @@ int __lock_page_killable(struct page *page)
> return __wait_on_bit_lock(page_waitqueue(page), &wait,
> sync_page_killable, TASK_KILLABLE);
> }
> +EXPORT_SYMBOL_GPL(__lock_page_killable);
Needed for modular use of lock_page_killable() - makes sense.
Please maintain these alongside the pohmelfs patchset.
On Tue, Jan 13, 2009 at 04:23:07PM -0800, Andrew Morton ([email protected]) wrote:
> Please maintain these alongside the pohmelfs patchset.
Yes, thank you.
I will send them together.
--
Evgeniy Polyakov
On Wed, 14 Jan 2009 02:05:33 +0300 Evgeniy Polyakov wrote:
> Signed-off-by: Evgeniy Polaykov <[email protected]>
>
> index 0000000..12ffa37
> --- /dev/null
> +++ b/drivers/staging/dst/Kconfig
> @@ -0,0 +1,71 @@
> +config DST
> + tristate "Distributed storage"
> + depends on NET && CRYPTO && SYSFS
> + select CONNECTOR
> + select LIBCRC32C
> + ---help---
> + DST is a network block device storage, which can be used to organize
> + exported storages on the remote nodes into the local block device.
> +
> + DST is a network block device storage, which can be used to organize
> + exported storages on the remote nodes into the local block device.
> +
argh. That paragraph above is still duplicated. :(
I suppose that you want to emphasize it.
> + DST works on top of any network media and protocol, it is just a matter
> + of configuration utility to understand the correct addresses. The most
> + common example is TCP over IP allows to pass through firewalls and
> + created remote backup storage in the different datacenter. DST requires
> + single port to be enabled on the exporting node and outgoing connections
> + on the local node.
---
~Randy
On Wed, 14 Jan 2009 02:09:43 +0300 Evgeniy Polyakov wrote:
> On Wed, Jan 14, 2009 at 02:05:33AM +0300, Evgeniy Polyakov ([email protected]) wrote:
> > --- /dev/null
> > +++ b/drivers/staging/dst/Kconfig
> > @@ -0,0 +1,71 @@
> > +config DST
> > + tristate "Distributed storage"
> > + depends on NET && CRYPTO && SYSFS
> > + select CONNECTOR
> > + select LIBCRC32C
>
> Above is not needed.
>
> --- ./drivers/staging/dst/Kconfig.old 2009-01-14 02:09:52.000000000 +0300
> +++ ./drivers/staging/dst/Kconfig 2009-01-14 02:10:02.000000000 +0300
> @@ -2,14 +2,10 @@
> tristate "Distributed storage"
> depends on NET && CRYPTO && SYSFS
> select CONNECTOR
> - select LIBCRC32C
> ---help---
> DST is a network block device storage, which can be used to organize
> exported storages on the remote nodes into the local block device.
>
> - DST is a network block device storage, which can be used to organize
> - exported storages on the remote nodes into the local block device.
> -
> DST works on top of any network media and protocol, it is just a matter
> of configuration utility to understand the correct addresses. The most
> common example is TCP over IP allows to pass through firewalls and
ah, i see.
---
~Randy
On Tue, Jan 13, 2009 at 06:22:51PM -0800, Randy Dunlap ([email protected]) wrote:
> > ---help---
> > DST is a network block device storage, which can be used to organize
> > exported storages on the remote nodes into the local block device.
> >
> > - DST is a network block device storage, which can be used to organize
> > - exported storages on the remote nodes into the local block device.
> > -
> > DST works on top of any network media and protocol, it is just a matter
> > of configuration utility to understand the correct addresses. The most
> > common example is TCP over IP allows to pass through firewalls and
>
> ah, i see.
I created patches against wrong tree, so it does not contain your
excellent language fixes and above paragraph was just a small part of
the needed patch :)
It exists in the exported git tree, but not this patch series.
--
Evgeniy Polyakov
Andrew Morton wrote:
> On Wed, 14 Jan 2009 03:20:08 +0300
> Evgeniy Polyakov <[email protected]> wrote:
>
>> And while you at it, please shed a
>> light on this exports for POHMELFS:
>>
>> --- a/mm/filemap.c
>> +++ b/mm/filemap.c
>> @@ -513,6 +513,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
>> }
>> return ret;
>> }
>> +EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
>
> OK by me.
>
>> #ifdef CONFIG_NUMA
>> struct page *__page_cache_alloc(gfp_t gfp)
>> @@ -627,6 +628,7 @@ int __lock_page_killable(struct page *page)
>> return __wait_on_bit_lock(page_waitqueue(page), &wait,
>> sync_page_killable, TASK_KILLABLE);
>> }
>> +EXPORT_SYMBOL_GPL(__lock_page_killable);
>
> Needed for modular use of lock_page_killable() - makes sense.
>
> Please maintain these alongside the pohmelfs patchset.
FWIW we definitely want pohmelfs in staging...
(yes, I realize we are discussing dst not pohmelfs)
Jeff
Hi Evgeniy,
On Wed, Jan 14, 2009 at 02:05:30AM +0300, Evgeniy Polyakov wrote:
[...]
> +void thread_pool_del_worker(struct thread_pool *p)
> +{
> + struct thread_pool_worker *w = NULL;
> +
> + while (!w) {
> + wait_event(p->wait, !list_empty(&p->ready_list) || !p->thread_num);
^^^^^^^^^^^^^^
What's the purpose of !p->thread_num here? Is there an exit case missing
in the loop below?
> +
> + dprintk("%s: locking list_empty: %d, thread_num: %d.\n",
> + __func__, list_empty(&p->ready_list), p->thread_num);
> +
> + mutex_lock(&p->thread_lock);
> + if (!list_empty(&p->ready_list)) {
> + w = list_first_entry(&p->ready_list,
> + struct thread_pool_worker,
> + worker_entry);
> +
> + dprintk("%s: deleting w: %p, thread_num: %d, list: %p [%p.%p].\n",
> + __func__, w, p->thread_num, &p->ready_list,
> + p->ready_list.prev, p->ready_list.next);
> +
> + p->thread_num--;
> + list_del(&w->worker_entry);
> + }
> + mutex_unlock(&p->thread_lock);
> + }
> +
> + if (w)
> + thread_pool_exit_worker(w);
> + dprintk("%s: deleted w: %p, thread_num: %d.\n",
> + __func__, w, p->thread_num);
> +}
On Wed, Jan 14 2009, Evgeniy Polyakov wrote:
> + bio = bio_alloc_bioset(GFP_KERNEL,
> + PAGE_ALIGN(cmd->size) >> PAGE_SHIFT,
> + dst_bio_set);
> + if (!bio)
> + goto err_out_exit;
> + bio->bi_private = NULL;
> +
> + priv = mempool_alloc(st->node->trans_pool, GFP_KERNEL);
> + if (!priv)
> + goto err_out_free;
Did you know that you can now set the appropriate extra size for your
private bio set, thus getting rid of this extra 'priv' allocation and
free for each bio?
See bioset_create().
--
Jens Axboe
Hi Frederik.
Thanks for the comment!
On Wed, Jan 14, 2009 at 03:46:02PM +0100, Frederik Deweerdt ([email protected]) wrote:
> On Wed, Jan 14, 2009 at 02:05:30AM +0300, Evgeniy Polyakov wrote:
> [...]
> > +void thread_pool_del_worker(struct thread_pool *p)
> > +{
> > + struct thread_pool_worker *w = NULL;
> > +
> > + while (!w) {
> > + wait_event(p->wait, !list_empty(&p->ready_list) || !p->thread_num);
> ^^^^^^^^^^^^^^
> What's the purpose of !p->thread_num here? Is there an exit case missing
> in the loop below?
It is needed if thread was not in the ready_list but existed because of
some global flag. Current code does not use simultaneous exit and this
function is entered only when there are threads in the pool, so it
should be correct. But if called by several threads, it should be an
exit condition. I will put it into the loop termination check for the
completeness.
--
Evgeniy Polyakov
On Wed, Jan 14, 2009 at 03:52:05PM +0100, Jens Axboe ([email protected]) wrote:
> On Wed, Jan 14 2009, Evgeniy Polyakov wrote:
> > + bio = bio_alloc_bioset(GFP_KERNEL,
> > + PAGE_ALIGN(cmd->size) >> PAGE_SHIFT,
> > + dst_bio_set);
> > + if (!bio)
> > + goto err_out_exit;
> > + bio->bi_private = NULL;
> > +
> > + priv = mempool_alloc(st->node->trans_pool, GFP_KERNEL);
> > + if (!priv)
> > + goto err_out_free;
>
> Did you know that you can now set the appropriate extra size for your
> private bio set, thus getting rid of this extra 'priv' allocation and
> free for each bio?
>
> See bioset_create().
Yes, that's a good idea, I will update the patch with that changes in
mind. Thanks Jens.
--
Evgeniy Polyakov
On Wed, 14 Jan 2009 02:05:30 +0300 Evgeniy Polyakov <[email protected]> wrote:
> Kernel currently does not allow to queue work into some entity which
> will perform it in the process context and have simple way to extend
> number of worker and work with them not as separate objects, but with
> pool as a whole. So thread pool model was implemented in the DST.
>
> Thread pool abstraction allows to schedule a work to be performed
> on behalf of kernel thread. One does not operate with threads itself,
> instead user provides setup and cleanup callbacks for thread pool itself,
> and action and cleanup callbacks for each submitted work.
>
> Each worker has private data initialized at creation time and data,
> provided by user at scheduling time.
>
> When action is being performed, thread can not be used by other users,
> instead they will sleep until there is free thread to pick their work.
>
> Thread pool is used for crypto processing of incoming and outgoing IO
> requests to reduce the overall overhead.
This is at least our fourth thread pool implementation, not counting
kernel/workqueue.c:
1: pdflush
2: David Howells' "slow work" infrastructure
3: Arjan van de Ven's kernel/async.c
4: Your "dst thread pool"
Guys, please. Let's get our act together here.
Hi Andrew.
On Wed, Jan 14, 2009 at 09:58:10PM -0800, Andrew Morton ([email protected]) wrote:
> > Kernel currently does not allow to queue work into some entity which
> > will perform it in the process context and have simple way to extend
> > number of worker and work with them not as separate objects, but with
> > pool as a whole. So thread pool model was implemented in the DST.
> >
> > Thread pool abstraction allows to schedule a work to be performed
> > on behalf of kernel thread. One does not operate with threads itself,
> > instead user provides setup and cleanup callbacks for thread pool itself,
> > and action and cleanup callbacks for each submitted work.
> >
> > Each worker has private data initialized at creation time and data,
> > provided by user at scheduling time.
> >
> > When action is being performed, thread can not be used by other users,
> > instead they will sleep until there is free thread to pick their work.
> >
> > Thread pool is used for crypto processing of incoming and outgoing IO
> > requests to reduce the overall overhead.
>
> This is at least our fourth thread pool implementation, not counting
> kernel/workqueue.c:
>
> 1: pdflush
It is not really a pool of threads. But its works is somewhat similar.
> 2: David Howells' "slow work" infrastructure
I did not check it, it was not sent to fsdevel and only couple of
replies sneaked, according to them there are questionable cases (like
lots of global variables), but overall I can not say more.
> 3: Arjan van de Ven's kernel/async.c
Arjan does not answer to the mails. I sent him a review with
constructive critics, but it got lost in the void :)
> 4: Your "dst thread pool"
This one is rather simple case: set of thrads and blocking callbacks to
add the work.
--
Evgeniy Polyakov
On Wed, 14 Jan 2009 21:58:10 -0800
Andrew Morton <[email protected]> wrote:
> > Thread pool is used for crypto processing of incoming and outgoing
> > IO requests to reduce the overall overhead.
>
> This is at least our fourth thread pool implementation, not counting
> kernel/workqueue.c:
>
> 1: pdflush
I will look at moving pdflush to async function calls.. sounds like a
good "get over jetlag" project
>
> 2: David Howells' "slow work" infrastructure
this one is *weird*. The infrastructure deals with object refcounting
somehow.
>
> 4: Your "dst thread pool"
from the context... I wouldn't be surprised if this can just use async
function calls as well... it's simple enough on first sight.
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
Hi.
On Sun, Jan 18, 2009 at 04:10:41PM -0800, Arjan van de Ven ([email protected]) wrote:
> > 4: Your "dst thread pool"
>
> from the context... I wouldn't be surprised if this can just use async
> function calls as well... it's simple enough on first sight.
No it can't. Since async function call requires additional allocation
which if failed fallbacks to the sync execution. This defeats the whole
purpose of the kernel thread. And this was already pointed to you Arjan,
but apparently you like to hide this.
Allocation in this path is very dangerous and even in case of atomic one
(which is used in the patch) this is a way heavy and unneded additional
overhead.
So neither DST nor pdflush should use such approach.
Arjan, please update your patch to met the feedback I gave in the
fsdevel mail list and do not allow to sneak the implementation if you do
not like the author :)
The only way to work with your async threads in the described cases is
to have a way to embed the needed event structure into the existing
objects like inode (which will be nacked by the fsdevel community for
reasone) or dst transaction (this may work). But existing size is
actually too big.
--
Evgeniy Polyakov