![Evgeniy Polyakov](/assets/img/avatar_default.png)
Use bio prepend feature as suggested by Jens Axboe. Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
658 lines
14 KiB
C
658 lines
14 KiB
C
/*
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* 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/blkdev.h>
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#include <linux/bio.h>
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#include <linux/dst.h>
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/socket.h>
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#include <net/sock.h>
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/*
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* Export bioset is used for server block IO requests.
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*/
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static struct bio_set *dst_bio_set;
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int __init dst_export_init(void)
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{
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int err = -ENOMEM;
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dst_bio_set = bioset_create(32, sizeof(struct dst_export_priv));
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if (!dst_bio_set)
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goto err_out_exit;
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return 0;
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err_out_exit:
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return err;
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}
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void dst_export_exit(void)
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{
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bioset_free(dst_bio_set);
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}
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/*
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* When client connects and autonegotiates with the server node,
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* its permissions are checked in a security attributes and sent
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* back.
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*/
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static unsigned int dst_check_permissions(struct dst_state *main, struct dst_state *st)
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{
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struct dst_node *n = main->node;
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struct dst_secure *sentry;
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struct dst_secure_user *s;
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struct saddr *sa = &st->ctl.addr;
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unsigned int perm = 0;
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mutex_lock(&n->security_lock);
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list_for_each_entry(sentry, &n->security_list, sec_entry) {
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s = &sentry->sec;
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if (s->addr.sa_family != sa->sa_family)
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continue;
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if (s->addr.sa_data_len != sa->sa_data_len)
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continue;
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/*
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* This '2' below is a port field. This may be very wrong to do
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* in atalk for example though. If there will be any need to extent
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* protocol to something else, I can create per-family helpers and
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* use them instead of this memcmp.
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*/
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if (memcmp(s->addr.sa_data + 2, sa->sa_data + 2,
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sa->sa_data_len - 2))
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continue;
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perm = s->permissions;
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}
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mutex_unlock(&n->security_lock);
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return perm;
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}
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/*
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* Accept new client: allocate appropriate network state and check permissions.
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*/
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static struct dst_state *dst_accept_client(struct dst_state *st)
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{
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unsigned int revents = 0;
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unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP;
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unsigned int mask = err_mask | POLLIN;
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struct dst_node *n = st->node;
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int err = 0;
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struct socket *sock = NULL;
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struct dst_state *new;
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while (!err && !sock) {
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revents = dst_state_poll(st);
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if (!(revents & mask)) {
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DEFINE_WAIT(wait);
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for (;;) {
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prepare_to_wait(&st->thread_wait,
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&wait, TASK_INTERRUPTIBLE);
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if (!n->trans_scan_timeout || st->need_exit)
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break;
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revents = dst_state_poll(st);
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if (revents & mask)
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break;
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if (signal_pending(current))
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break;
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/*
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* Magic HZ? Polling check above is not safe in
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* all cases (like socket reset in BH context),
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* so it is simpler just to postpone it to the
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* process context instead of implementing special
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* locking there.
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*/
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schedule_timeout(HZ);
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}
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finish_wait(&st->thread_wait, &wait);
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}
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err = -ECONNRESET;
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dst_state_lock(st);
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dprintk("%s: st: %p, revents: %x [err: %d, in: %d].\n",
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__func__, st, revents, revents & err_mask,
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revents & POLLIN);
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if (revents & err_mask) {
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dprintk("%s: revents: %x, socket: %p, err: %d.\n",
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__func__, revents, st->socket, err);
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err = -ECONNRESET;
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}
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if (!n->trans_scan_timeout || st->need_exit)
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err = -ENODEV;
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if (st->socket && (revents & POLLIN))
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err = kernel_accept(st->socket, &sock, 0);
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dst_state_unlock(st);
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}
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if (err)
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goto err_out_exit;
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new = dst_state_alloc(st->node);
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if (!new) {
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err = -ENOMEM;
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goto err_out_release;
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}
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new->socket = sock;
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new->ctl.addr.sa_data_len = sizeof(struct sockaddr);
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err = kernel_getpeername(sock, (struct sockaddr *)&new->ctl.addr,
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(int *)&new->ctl.addr.sa_data_len);
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if (err)
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goto err_out_put;
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new->permissions = dst_check_permissions(st, new);
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if (new->permissions == 0) {
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err = -EPERM;
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dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr,
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"Client is not allowed to connect");
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goto err_out_put;
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}
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err = dst_poll_init(new);
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if (err)
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goto err_out_put;
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dst_dump_addr(sock, (struct sockaddr *)&new->ctl.addr,
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"Connected client");
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return new;
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err_out_put:
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dst_state_put(new);
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err_out_release:
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sock_release(sock);
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err_out_exit:
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return ERR_PTR(err);
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}
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/*
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* Each server's block request sometime finishes.
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* Usually it happens in hard irq context of the appropriate controller,
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* so to play good with all cases we just queue BIO into the queue
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* and wake up processing thread, which gets completed request and
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* send (encrypting if needed) it back to the client (if it was a read
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* request), or sends back reply that writing succesfully completed.
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*/
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static int dst_export_process_request_queue(struct dst_state *st)
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{
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unsigned long flags;
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struct dst_export_priv *p = NULL;
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struct bio *bio;
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int err = 0;
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while (!list_empty(&st->request_list)) {
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spin_lock_irqsave(&st->request_lock, flags);
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if (!list_empty(&st->request_list)) {
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p = list_first_entry(&st->request_list,
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struct dst_export_priv, request_entry);
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list_del(&p->request_entry);
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}
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spin_unlock_irqrestore(&st->request_lock, flags);
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if (!p)
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break;
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bio = p->bio;
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if (dst_need_crypto(st->node) && (bio_data_dir(bio) == READ))
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err = dst_export_crypto(st->node, bio);
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else
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err = dst_export_send_bio(bio);
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if (err)
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break;
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}
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return err;
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}
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/*
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* Cleanup export state.
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* It has to wait until all requests are finished,
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* and then free them all.
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*/
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static void dst_state_cleanup_export(struct dst_state *st)
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{
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struct dst_export_priv *p;
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unsigned long flags;
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/*
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* This loop waits for all pending bios to be completed and freed.
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*/
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while (atomic_read(&st->refcnt) > 1) {
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dprintk("%s: st: %p, refcnt: %d, list_empty: %d.\n",
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__func__, st, atomic_read(&st->refcnt),
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list_empty(&st->request_list));
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wait_event_timeout(st->thread_wait,
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(atomic_read(&st->refcnt) == 1) ||
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!list_empty(&st->request_list),
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HZ/2);
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while (!list_empty(&st->request_list)) {
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p = NULL;
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spin_lock_irqsave(&st->request_lock, flags);
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if (!list_empty(&st->request_list)) {
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p = list_first_entry(&st->request_list,
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struct dst_export_priv, request_entry);
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list_del(&p->request_entry);
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}
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spin_unlock_irqrestore(&st->request_lock, flags);
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if (p)
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bio_put(p->bio);
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dprintk("%s: st: %p, refcnt: %d, list_empty: %d, p: %p.\n",
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__func__, st, atomic_read(&st->refcnt),
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list_empty(&st->request_list), p);
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}
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}
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dst_state_put(st);
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}
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/*
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* Client accepting thread.
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* Not only accepts new connection, but also schedules receiving thread
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* and performs request completion described above.
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*/
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static int dst_accept(void *init_data, void *schedule_data)
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{
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struct dst_state *main_st = schedule_data;
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struct dst_node *n = init_data;
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struct dst_state *st;
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int err;
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while (n->trans_scan_timeout && !main_st->need_exit) {
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dprintk("%s: main_st: %p, n: %p.\n", __func__, main_st, n);
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st = dst_accept_client(main_st);
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if (IS_ERR(st))
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continue;
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err = dst_state_schedule_receiver(st);
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if (!err) {
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while (n->trans_scan_timeout) {
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err = wait_event_interruptible_timeout(st->thread_wait,
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!list_empty(&st->request_list) ||
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!n->trans_scan_timeout ||
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st->need_exit,
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HZ);
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if (!n->trans_scan_timeout || st->need_exit)
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break;
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if (list_empty(&st->request_list))
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continue;
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err = dst_export_process_request_queue(st);
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if (err)
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break;
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}
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st->need_exit = 1;
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wake_up(&st->thread_wait);
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}
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dst_state_cleanup_export(st);
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}
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dprintk("%s: freeing listening socket st: %p.\n", __func__, main_st);
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dst_state_lock(main_st);
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dst_poll_exit(main_st);
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dst_state_socket_release(main_st);
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dst_state_unlock(main_st);
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dst_state_put(main_st);
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dprintk("%s: freed listening socket st: %p.\n", __func__, main_st);
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return 0;
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}
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int dst_start_export(struct dst_node *n)
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{
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if (list_empty(&n->security_list)) {
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printk(KERN_ERR "You are trying to export node '%s' without security attributes.\n"
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"No clients will be allowed to connect. Exiting.\n", n->name);
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return -EINVAL;
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}
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return dst_node_trans_init(n, sizeof(struct dst_export_priv));
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}
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/*
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* Initialize listening state and schedule accepting thread.
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*/
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int dst_node_init_listened(struct dst_node *n, struct dst_export_ctl *le)
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{
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struct dst_state *st;
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int err = -ENOMEM;
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struct dst_network_ctl *ctl = &le->ctl;
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memcpy(&n->info->net, ctl, sizeof(struct dst_network_ctl));
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st = dst_state_alloc(n);
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if (IS_ERR(st)) {
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err = PTR_ERR(st);
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goto err_out_exit;
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}
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memcpy(&st->ctl, ctl, sizeof(struct dst_network_ctl));
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err = dst_state_socket_create(st);
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if (err)
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goto err_out_put;
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st->socket->sk->sk_reuse = 1;
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err = kernel_bind(st->socket, (struct sockaddr *)&ctl->addr,
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ctl->addr.sa_data_len);
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if (err)
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goto err_out_socket_release;
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err = kernel_listen(st->socket, 1024);
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if (err)
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goto err_out_socket_release;
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n->state = st;
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err = dst_poll_init(st);
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if (err)
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goto err_out_socket_release;
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dst_state_get(st);
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err = thread_pool_schedule(n->pool, dst_thread_setup,
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dst_accept, st, MAX_SCHEDULE_TIMEOUT);
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if (err)
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goto err_out_poll_exit;
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return 0;
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err_out_poll_exit:
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dst_poll_exit(st);
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err_out_socket_release:
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dst_state_socket_release(st);
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err_out_put:
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dst_state_put(st);
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err_out_exit:
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n->state = NULL;
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return err;
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}
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/*
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* Free bio and related private data.
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* Also drop a reference counter for appropriate state,
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* which waits when there are no more block IOs in-flight.
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*/
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static void dst_bio_destructor(struct bio *bio)
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{
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struct bio_vec *bv;
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struct dst_export_priv *priv = bio->bi_private;
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int i;
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bio_for_each_segment(bv, bio, i) {
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if (!bv->bv_page)
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break;
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__free_page(bv->bv_page);
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}
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if (priv)
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dst_state_put(priv->state);
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bio_free(bio, dst_bio_set);
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}
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/*
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* Block IO completion. Queue request to be sent back to
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* the client (or just confirmation).
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*/
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static void dst_bio_end_io(struct bio *bio, int err)
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{
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struct dst_export_priv *p = bio->bi_private;
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struct dst_state *st = p->state;
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unsigned long flags;
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spin_lock_irqsave(&st->request_lock, flags);
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list_add_tail(&p->request_entry, &st->request_list);
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spin_unlock_irqrestore(&st->request_lock, flags);
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wake_up(&st->thread_wait);
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}
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/*
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* Allocate read request for the server.
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*/
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static int dst_export_read_request(struct bio *bio, unsigned int total_size)
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{
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unsigned int size;
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struct page *page;
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int err;
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while (total_size) {
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err = -ENOMEM;
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page = alloc_page(GFP_KERNEL);
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if (!page)
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goto err_out_exit;
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size = min_t(unsigned int, PAGE_SIZE, total_size);
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err = bio_add_page(bio, page, size, 0);
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dprintk("%s: bio: %llu/%u, size: %u, err: %d.\n",
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__func__, (u64)bio->bi_sector, bio->bi_size,
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size, err);
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if (err <= 0)
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goto err_out_free_page;
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total_size -= size;
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}
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return 0;
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err_out_free_page:
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__free_page(page);
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err_out_exit:
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return err;
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}
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/*
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* Allocate write request for the server.
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* Should not only get pages, but also read data from the network.
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*/
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static int dst_export_write_request(struct dst_state *st,
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struct bio *bio, unsigned int total_size)
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{
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unsigned int size;
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struct page *page;
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void *data;
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int err;
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while (total_size) {
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err = -ENOMEM;
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page = alloc_page(GFP_KERNEL);
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if (!page)
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goto err_out_exit;
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data = kmap(page);
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if (!data)
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goto err_out_free_page;
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size = min_t(unsigned int, PAGE_SIZE, total_size);
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err = dst_data_recv(st, data, size);
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if (err)
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goto err_out_unmap_page;
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err = bio_add_page(bio, page, size, 0);
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if (err <= 0)
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goto err_out_unmap_page;
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kunmap(page);
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total_size -= size;
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}
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return 0;
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err_out_unmap_page:
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kunmap(page);
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err_out_free_page:
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__free_page(page);
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err_out_exit:
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return err;
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}
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/*
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* Groovy, we've gotten an IO request from the client.
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* Allocate BIO from the bioset, private data from the mempool
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* and lots of pages for IO.
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*/
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int dst_process_io(struct dst_state *st)
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{
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struct dst_node *n = st->node;
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struct dst_cmd *cmd = st->data;
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struct bio *bio;
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struct dst_export_priv *priv;
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int err = -ENOMEM;
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if (unlikely(!n->bdev)) {
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err = -EINVAL;
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goto err_out_exit;
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}
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bio = bio_alloc_bioset(GFP_KERNEL,
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PAGE_ALIGN(cmd->size) >> PAGE_SHIFT,
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dst_bio_set);
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if (!bio)
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goto err_out_exit;
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|
|
priv = (struct dst_export_priv *)(((void *)bio) - sizeof (struct dst_export_priv));
|
|
|
|
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;
|
|
}
|