diff --git a/drivers/staging/dst/export.c b/drivers/staging/dst/export.c new file mode 100644 index 000000000000..122fe7577dcb --- /dev/null +++ b/drivers/staging/dst/export.c @@ -0,0 +1,664 @@ +/* + * 2007+ Copyright (c) Evgeniy Polyakov + * 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 +#include +#include +#include +#include +#include +#include +#include + +#include + +/* + * 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; +}