drivers/staging/pohmelfs/net.c

   1 /*
   2  * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
   3  * All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/fsnotify.h>
  17 #include <linux/jhash.h>
  18 #include <linux/in.h>
  19 #include <linux/in6.h>
  20 #include <linux/kthread.h>
  21 #include <linux/pagemap.h>
  22 #include <linux/poll.h>
  23 #include <linux/slab.h>
  24 #include <linux/swap.h>
  25 #include <linux/syscalls.h>
  26 #include <linux/vmalloc.h>
  27
  28 #include "netfs.h"
  29
  30 /*
  31  * Async machinery lives here.
  32  * All commands being sent to server do _not_ require sync reply,
  33  * instead, if it is really needed, like readdir or readpage, caller
  34  * sleeps waiting for data, which will be placed into provided buffer
  35  * and caller will be awakened.
  36  *
  37  * Every command response can come without some listener. For example
  38  * readdir response will add new objects into cache without appropriate
  39  * request from userspace. This is used in cache coherency.
  40  *
  41  * If object is not found for given data, it is discarded.
  42  *
  43  * All requests are received by dedicated kernel thread.
  44  */
  45
  46 /*
  47  * Basic network sending/receiving functions.
  48  * Blocked mode is used.
  49  */
  50 static int netfs_data_recv(struct netfs_state *st, void *buf, u64 size)
  51 {
  52         struct msghdr msg;
  53         struct kvec iov;
  54         int err;
  55
  56         BUG_ON(!size);
  57
  58         iov.iov_base = buf;
  59         iov.iov_len = size;
  60
  61         msg.msg_iov = (struct iovec *)&iov;
  62         msg.msg_iovlen = 1;
  63         msg.msg_name = NULL;
  64         msg.msg_namelen = 0;
  65         msg.msg_control = NULL;
  66         msg.msg_controllen = 0;
  67         msg.msg_flags = MSG_DONTWAIT;
  68
  69         err = kernel_recvmsg(st->socket, &msg, &iov, 1, iov.iov_len,
  70                         msg.msg_flags);
  71         if (err <= 0) {
  72                 printk("%s: failed to recv data: size: %llu, err: %d.\n", __func__, size, err);
  73                 if (err == 0)
  74                         err = -ECONNRESET;
  75         }
  76
  77         return err;
  78 }
  79
  80 static int pohmelfs_data_recv(struct netfs_state *st, void *data, unsigned int size)
  81 {
  82         unsigned int revents = 0;
  83         unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP;
  84         unsigned int mask = err_mask | POLLIN;
  85         int err = 0;
  86
  87         while (size && !err) {
  88                 revents = netfs_state_poll(st);
  89
  90                 if (!(revents & mask)) {
  91                         DEFINE_WAIT(wait);
  92
  93                         for (;;) {
  94                                 prepare_to_wait(&st->thread_wait, &wait, TASK_INTERRUPTIBLE);
  95                                 if (kthread_should_stop())
  96                                         break;
  97
  98                                 revents = netfs_state_poll(st);
  99
 100                                 if (revents & mask)
 101                                         break;
 102
 103                                 if (signal_pending(current))
 104                                         break;
 105
 106                                 schedule();
 107                                 continue;
 108                         }
 109                         finish_wait(&st->thread_wait, &wait);
 110                 }
 111
 112                 err = 0;
 113                 netfs_state_lock(st);
 114                 if (st->socket && (st->read_socket == st->socket) && (revents & POLLIN)) {
 115                         err = netfs_data_recv(st, data, size);
 116                         if (err > 0) {
 117                                 data += err;
 118                                 size -= err;
 119                                 err = 0;
 120                         } else if (err == 0)
 121                                 err = -ECONNRESET;
 122                 }
 123
 124                 if (revents & err_mask) {
 125                         printk("%s: revents: %x, socket: %p, size: %u, err: %d.\n",
 126                                         __func__, revents, st->socket, size, err);
 127                         err = -ECONNRESET;
 128                 }
 129                 netfs_state_unlock(st);
 130
 131                 if (err < 0) {
 132                         if (netfs_state_trylock_send(st)) {
 133                                 netfs_state_exit(st);
 134                                 err = netfs_state_init(st);
 135                                 if (!err)
 136                                         err = -EAGAIN;
 137                                 netfs_state_unlock_send(st);
 138                         } else {
 139                                 st->need_reset = 1;
 140                         }
 141                 }
 142
 143                 if (kthread_should_stop())
 144                         err = -ENODEV;
 145
 146                 if (err)
 147                         printk("%s: socket: %p, read_socket: %p, revents: %x, rev_error: %d, "
 148                                         "should_stop: %d, size: %u, err: %d.\n",
 149                                 __func__, st->socket, st->read_socket,
 150                                 revents, revents & err_mask, kthread_should_stop(), size, err);
 151         }
 152
 153         return err;
 154 }
 155
 156 int pohmelfs_data_recv_and_check(struct netfs_state *st, void *data, unsigned int size)
 157 {
 158         struct netfs_cmd *cmd = &st->cmd;
 159         int err;
 160
 161         err = pohmelfs_data_recv(st, data, size);
 162         if (err)
 163                 return err;
 164
 165         return pohmelfs_crypto_process_input_data(&st->eng, cmd->iv, data, NULL, size);
 166 }
 167
 168 /*
 169  * Polling machinery.
 170  */
 171
 172 struct netfs_poll_helper {
 173         poll_table              pt;
 174         struct netfs_state      *st;
 175 };
 176
 177 static int netfs_queue_wake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 178 {
 179         struct netfs_state *st = container_of(wait, struct netfs_state, wait);
 180
 181         wake_up(&st->thread_wait);
 182         return 1;
 183 }
 184
 185 static void netfs_queue_func(struct file *file, wait_queue_head_t *whead,
 186                                  poll_table *pt)
 187 {
 188         struct netfs_state *st = container_of(pt, struct netfs_poll_helper, pt)->st;
 189
 190         st->whead = whead;
 191         init_waitqueue_func_entry(&st->wait, netfs_queue_wake);
 192         add_wait_queue(whead, &st->wait);
 193 }
 194
 195 static void netfs_poll_exit(struct netfs_state *st)
 196 {
 197         if (st->whead) {
 198                 remove_wait_queue(st->whead, &st->wait);
 199                 st->whead = NULL;
 200         }
 201 }
 202
 203 static int netfs_poll_init(struct netfs_state *st)
 204 {
 205         struct netfs_poll_helper ph;
 206
 207         ph.st = st;
 208         init_poll_funcptr(&ph.pt, &netfs_queue_func);
 209
 210         st->socket->ops->poll(NULL, st->socket, &ph.pt);
 211         return 0;
 212 }
 213
 214 /*
 215  * Get response for readpage command. We search inode and page in its mapping
 216  * and copy data into. If it was async request, then we queue page into shared
 217  * data and wakeup listener, who will copy it to userspace.
 218  *
 219  * There is a work in progress of allowing to call copy_to_user() directly from
 220  * async receiving kernel thread.
 221  */
 222 static int pohmelfs_read_page_response(struct netfs_state *st)
 223 {
 224         struct pohmelfs_sb *psb = st->psb;
 225         struct netfs_cmd *cmd = &st->cmd;
 226         struct inode *inode;
 227         struct page *page;
 228         int err = 0;
 229
 230         if (cmd->size > PAGE_CACHE_SIZE) {
 231                 err = -EINVAL;
 232                 goto err_out_exit;
 233         }
 234
 235         inode = ilookup(st->psb->sb, cmd->id);
 236         if (!inode) {
 237                 printk("%s: failed to find inode: id: %llu.\n", __func__, cmd->id);
 238                 err = -ENOENT;
 239                 goto err_out_exit;
 240         }
 241
 242         page = find_get_page(inode->i_mapping, cmd->start >> PAGE_CACHE_SHIFT);
 243         if (!page || !PageLocked(page)) {
 244                 printk("%s: failed to find/lock page: page: %p, id: %llu, start: %llu, index: %llu.\n",
 245                                 __func__, page, cmd->id, cmd->start, cmd->start >> PAGE_CACHE_SHIFT);
 246
 247                 while (cmd->size) {
 248                         unsigned int sz = min(cmd->size, st->size);
 249
 250                         err = pohmelfs_data_recv(st, st->data, sz);
 251                         if (err)
 252                                 break;
 253
 254                         cmd->size -= sz;
 255                 }
 256
 257                 err = -ENODEV;
 258                 if (page)
 259                         goto err_out_page_put;
 260                 goto err_out_put;
 261         }
 262
 263         if (cmd->size) {
 264                 void *addr;
 265
 266                 addr = kmap(page);
 267                 err = pohmelfs_data_recv(st, addr, cmd->size);
 268                 kunmap(page);
 269
 270                 if (err)
 271                         goto err_out_page_unlock;
 272         }
 273
 274         dprintk("%s: page: %p, start: %llu, size: %u, locked: %d.\n",
 275                 __func__, page, cmd->start, cmd->size, PageLocked(page));
 276
 277         SetPageChecked(page);
 278         if ((psb->hash_string || psb->cipher_string) && psb->perform_crypto && cmd->size) {
 279                 err = pohmelfs_crypto_process_input_page(&st->eng, page, cmd->size, cmd->iv);
 280                 if (err < 0)
 281                         goto err_out_page_unlock;
 282         } else {
 283                 SetPageUptodate(page);
 284                 unlock_page(page);
 285                 page_cache_release(page);
 286         }
 287
 288         pohmelfs_put_inode(POHMELFS_I(inode));
 289         wake_up(&st->psb->wait);
 290
 291         return 0;
 292
 293 err_out_page_unlock:
 294         SetPageError(page);
 295         unlock_page(page);
 296 err_out_page_put:
 297         page_cache_release(page);
 298 err_out_put:
 299         pohmelfs_put_inode(POHMELFS_I(inode));
 300 err_out_exit:
 301         wake_up(&st->psb->wait);
 302         return err;
 303 }
 304
 305 static int pohmelfs_check_name(struct pohmelfs_inode *parent, struct qstr *str,
 306                 struct netfs_inode_info *info)
 307 {
 308         struct inode *inode;
 309         struct pohmelfs_name *n;
 310         int err = 0;
 311         u64 ino = 0;
 312
 313         mutex_lock(&parent->offset_lock);
 314         n = pohmelfs_search_hash(parent, str->hash);
 315         if (n)
 316                 ino = n->ino;
 317         mutex_unlock(&parent->offset_lock);
 318
 319         if (!ino)
 320                 goto out;
 321
 322         inode = ilookup(parent->vfs_inode.i_sb, ino);
 323         if (!inode)
 324                 goto out;
 325
 326         dprintk("%s: parent: %llu, inode: %llu.\n", __func__, parent->ino, ino);
 327
 328         pohmelfs_fill_inode(inode, info);
 329         pohmelfs_put_inode(POHMELFS_I(inode));
 330         err = -EEXIST;
 331 out:
 332         return err;
 333 }
 334
 335 /*
 336  * Readdir response from server. If special field is set, we wakeup
 337  * listener (readdir() call), which will copy data to userspace.
 338  */
 339 static int pohmelfs_readdir_response(struct netfs_state *st)
 340 {
 341         struct inode *inode;
 342         struct netfs_cmd *cmd = &st->cmd;
 343         struct netfs_inode_info *info;
 344         struct pohmelfs_inode *parent = NULL, *npi;
 345         int err = 0, last = cmd->ext;
 346         struct qstr str;
 347
 348         if (cmd->size > st->size)
 349                 return -EINVAL;
 350
 351         inode = ilookup(st->psb->sb, cmd->id);
 352         if (!inode) {
 353                 printk("%s: failed to find inode: id: %llu.\n", __func__, cmd->id);
 354                 return -ENOENT;
 355         }
 356         parent = POHMELFS_I(inode);
 357
 358         if (!cmd->size && cmd->start) {
 359                 err = -cmd->start;
 360                 goto out;
 361         }
 362
 363         if (cmd->size) {
 364                 char *name;
 365
 366                 err = pohmelfs_data_recv_and_check(st, st->data, cmd->size);
 367                 if (err)
 368                         goto err_out_put;
 369
 370                 info = (struct netfs_inode_info *)(st->data);
 371
 372                 name = (char *)(info + 1);
 373                 str.len = cmd->size - sizeof(struct netfs_inode_info) - 1 - cmd->cpad;
 374                 name[str.len] = 0;
 375                 str.name = name;
 376                 str.hash = jhash(str.name, str.len, 0);
 377
 378                 netfs_convert_inode_info(info);
 379
 380                 if (parent) {
 381                         err = pohmelfs_check_name(parent, &str, info);
 382                         if (err) {
 383                                 if (err == -EEXIST)
 384                                         err = 0;
 385                                 goto out;
 386                         }
 387                 }
 388
 389                 info->ino = cmd->start;
 390                 if (!info->ino)
 391                         info->ino = pohmelfs_new_ino(st->psb);
 392
 393                 dprintk("%s: parent: %llu, ino: %llu, name: '%s', hash: %x, len: %u, mode: %o.\n",
 394                                 __func__, parent->ino, info->ino, str.name, str.hash, str.len,
 395                                 info->mode);
 396
 397                 npi = pohmelfs_new_inode(st->psb, parent, &str, info, 0);
 398                 if (IS_ERR(npi)) {
 399                         err = PTR_ERR(npi);
 400
 401                         if (err != -EEXIST)
 402                                 goto err_out_put;
 403                 } else {
 404                         struct dentry *dentry, *alias, *pd;
 405
 406                         set_bit(NETFS_INODE_REMOTE_SYNCED, &npi->state);
 407                         clear_bit(NETFS_INODE_OWNED, &npi->state);
 408
 409                         pd = d_find_alias(&parent->vfs_inode);
 410                         if (pd) {
 411                                 str.hash = full_name_hash(str.name, str.len);
 412                                 dentry = d_alloc(pd, &str);
 413                                 if (dentry) {
 414                                         alias = d_materialise_unique(dentry, &npi->vfs_inode);
 415                                         if (alias)
 416                                                 dput(dentry);
 417                                 }
 418
 419                                 dput(dentry);
 420                                 dput(pd);
 421                         }
 422                 }
 423         }
 424 out:
 425         if (last) {
 426                 set_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &parent->state);
 427                 set_bit(NETFS_INODE_REMOTE_SYNCED, &parent->state);
 428                 wake_up(&st->psb->wait);
 429         }
 430         pohmelfs_put_inode(parent);
 431
 432         return err;
 433
 434 err_out_put:
 435         clear_bit(NETFS_INODE_REMOTE_DIR_SYNCED, &parent->state);
 436         printk("%s: parent: %llu, ino: %llu, cmd_id: %llu.\n", __func__, parent->ino, cmd->start, cmd->id);
 437         pohmelfs_put_inode(parent);
 438         wake_up(&st->psb->wait);
 439         return err;
 440 }
 441
 442 /*
 443  * Lookup command response.
 444  * It searches for inode to be looked at (if it exists) and substitutes
 445  * its inode information (size, permission, mode and so on), if inode does
 446  * not exist, new one will be created and inserted into caches.
 447  */
 448 static int pohmelfs_lookup_response(struct netfs_state *st)
 449 {
 450         struct inode *inode = NULL;
 451         struct netfs_cmd *cmd = &st->cmd;
 452         struct netfs_inode_info *info;
 453         struct pohmelfs_inode *parent = NULL, *npi;
 454         int err = -EINVAL;
 455         char *name;
 456
 457         inode = ilookup(st->psb->sb, cmd->id);
 458         if (!inode) {
 459                 printk("%s: lookup response: id: %llu, start: %llu, size: %u.\n",
 460                                 __func__, cmd->id, cmd->start, cmd->size);
 461                 err = -ENOENT;
 462                 goto err_out_exit;
 463         }
 464         parent = POHMELFS_I(inode);
 465
 466         if (!cmd->size) {
 467                 err = -cmd->start;
 468                 goto err_out_put;
 469         }
 470
 471         if (cmd->size < sizeof(struct netfs_inode_info)) {
 472                 printk("%s: broken lookup response: id: %llu, start: %llu, size: %u.\n",
 473                                 __func__, cmd->id, cmd->start, cmd->size);
 474                 err = -EINVAL;
 475                 goto err_out_put;
 476         }
 477
 478         err = pohmelfs_data_recv_and_check(st, st->data, cmd->size);
 479         if (err)
 480                 goto err_out_put;
 481
 482         info = (struct netfs_inode_info *)(st->data);
 483         name = (char *)(info + 1);
 484
 485         netfs_convert_inode_info(info);
 486
 487         info->ino = cmd->start;
 488         if (!info->ino)
 489                 info->ino = pohmelfs_new_ino(st->psb);
 490
 491         dprintk("%s: parent: %llu, ino: %llu, name: '%s', start: %llu.\n",
 492                         __func__, parent->ino, info->ino, name, cmd->start);
 493
 494         if (cmd->start)
 495                 npi = pohmelfs_new_inode(st->psb, parent, NULL, info, 0);
 496         else {
 497                 struct qstr str;
 498
 499                 str.name = name;
 500                 str.len = cmd->size - sizeof(struct netfs_inode_info) - 1 - cmd->cpad;
 501                 str.hash = jhash(name, str.len, 0);
 502
 503                 npi = pohmelfs_new_inode(st->psb, parent, &str, info, 0);
 504         }
 505         if (IS_ERR(npi)) {
 506                 err = PTR_ERR(npi);
 507
 508                 if (err != -EEXIST)
 509                         goto err_out_put;
 510         } else {
 511                 set_bit(NETFS_INODE_REMOTE_SYNCED, &npi->state);
 512                 clear_bit(NETFS_INODE_OWNED, &npi->state);
 513         }
 514
 515         clear_bit(NETFS_COMMAND_PENDING, &parent->state);
 516         pohmelfs_put_inode(parent);
 517
 518         wake_up(&st->psb->wait);
 519
 520         return 0;
 521
 522 err_out_put:
 523         pohmelfs_put_inode(parent);
 524 err_out_exit:
 525         clear_bit(NETFS_COMMAND_PENDING, &parent->state);
 526         wake_up(&st->psb->wait);
 527         printk("%s: inode: %p, id: %llu, start: %llu, size: %u, err: %d.\n",
 528                         __func__, inode, cmd->id, cmd->start, cmd->size, err);
 529         return err;
 530 }
 531
 532 /*
 533  * Create response, just marks local inode as 'created', so that writeback
 534  * for any of its children (or own) would not try to sync it again.
 535  */
 536 static int pohmelfs_create_response(struct netfs_state *st)
 537 {
 538         struct inode *inode;
 539         struct netfs_cmd *cmd = &st->cmd;
 540         struct pohmelfs_inode *pi;
 541
 542         inode = ilookup(st->psb->sb, cmd->id);
 543         if (!inode) {
 544                 printk("%s: failed to find inode: id: %llu, start: %llu.\n",
 545                                 __func__, cmd->id, cmd->start);
 546                 goto err_out_exit;
 547         }
 548
 549         pi = POHMELFS_I(inode);
 550
 551         /*
 552          * To lock or not to lock?
 553          * We actually do not care if it races...
 554          */
 555         if (cmd->start)
 556                 make_bad_inode(inode);
 557         set_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state);
 558
 559         pohmelfs_put_inode(pi);
 560
 561         wake_up(&st->psb->wait);
 562         return 0;
 563
 564 err_out_exit:
 565         wake_up(&st->psb->wait);
 566         return -ENOENT;
 567 }
 568
 569 /*
 570  * Object remove response. Just says that remove request has been received.
 571  * Used in cache coherency protocol.
 572  */
 573 static int pohmelfs_remove_response(struct netfs_state *st)
 574 {
 575         struct netfs_cmd *cmd = &st->cmd;
 576         int err;
 577
 578         err = pohmelfs_data_recv_and_check(st, st->data, cmd->size);
 579         if (err)
 580                 return err;
 581
 582         dprintk("%s: parent: %llu, path: '%s'.\n", __func__, cmd->id, (char *)st->data);
 583
 584         return 0;
 585 }
 586
 587 /*
 588  * Transaction reply processing.
 589  *
 590  * Find transaction based on its generation number, bump its reference counter,
 591  * so that none could free it under us, drop from the trees and lists and
 592  * drop reference counter. When it hits zero (when all destinations replied
 593  * and all timeout handled by async scanning code), completion will be called
 594  * and transaction will be freed.
 595  */
 596 static int pohmelfs_transaction_response(struct netfs_state *st)
 597 {
 598         struct netfs_trans_dst *dst;
 599         struct netfs_trans *t = NULL;
 600         struct netfs_cmd *cmd = &st->cmd;
 601         short err = (signed)cmd->ext;
 602
 603         mutex_lock(&st->trans_lock);
 604         dst = netfs_trans_search(st, cmd->start);
 605         if (dst) {
 606                 netfs_trans_remove_nolock(dst, st);
 607                 t = dst->trans;
 608         }
 609         mutex_unlock(&st->trans_lock);
 610
 611         if (!t) {
 612                 printk("%s: failed to find transaction: start: %llu: id: %llu, size: %u, ext: %u.\n",
 613                                 __func__, cmd->start, cmd->id, cmd->size, cmd->ext);
 614                 err = -EINVAL;
 615                 goto out;
 616         }
 617
 618         t->result = err;
 619         netfs_trans_drop_dst_nostate(dst);
 620
 621 out:
 622         wake_up(&st->psb->wait);
 623         return err;
 624 }
 625
 626 /*
 627  * Inode metadata cache coherency message.
 628  */
 629 static int pohmelfs_page_cache_response(struct netfs_state *st)
 630 {
 631         struct netfs_cmd *cmd = &st->cmd;
 632         struct inode *inode;
 633
 634         dprintk("%s: st: %p, id: %llu, start: %llu, size: %u.\n", __func__, st, cmd->id, cmd->start, cmd->size);
 635
 636         inode = ilookup(st->psb->sb, cmd->id);
 637         if (!inode) {
 638                 printk("%s: failed to find inode: id: %llu.\n", __func__, cmd->id);
 639                 return -ENOENT;
 640         }
 641
 642         set_bit(NETFS_INODE_NEED_FLUSH, &POHMELFS_I(inode)->state);
 643         pohmelfs_put_inode(POHMELFS_I(inode));
 644
 645         return 0;
 646 }
 647
 648 /*
 649  * Root capabilities response: export statistics
 650  * like used and available size, number of files and dirs,
 651  * permissions.
 652  */
 653 static int pohmelfs_root_cap_response(struct netfs_state *st)
 654 {
 655         struct netfs_cmd *cmd = &st->cmd;
 656         struct netfs_root_capabilities *cap;
 657         struct pohmelfs_sb *psb = st->psb;
 658
 659         if (cmd->size != sizeof(struct netfs_root_capabilities)) {
 660                 psb->flags = EPROTO;
 661                 wake_up(&psb->wait);
 662                 return -EPROTO;
 663         }
 664
 665         cap = st->data;
 666
 667         netfs_convert_root_capabilities(cap);
 668
 669         if (psb->total_size < cap->used + cap->avail)
 670                 psb->total_size = cap->used + cap->avail;
 671         if (cap->avail)
 672                 psb->avail_size = cap->avail;
 673         psb->state_flags = cap->flags;
 674
 675         if (psb->state_flags & POHMELFS_FLAGS_RO) {
 676                 psb->sb->s_flags |= MS_RDONLY;
 677                 printk(KERN_INFO "Mounting POHMELFS (%d) read-only.\n", psb->idx);
 678         }
 679
 680         if (psb->state_flags & POHMELFS_FLAGS_XATTR)
 681                 printk(KERN_INFO "Mounting POHMELFS (%d) "
 682                         "with extended attributes support.\n", psb->idx);
 683
 684         if (atomic_long_read(&psb->total_inodes) <= 1)
 685                 atomic_long_set(&psb->total_inodes, cap->nr_files);
 686
 687         dprintk("%s: total: %llu, avail: %llu, flags: %llx, inodes: %llu.\n",
 688                 __func__, psb->total_size, psb->avail_size, psb->state_flags, cap->nr_files);
 689
 690         psb->flags = 0;
 691         wake_up(&psb->wait);
 692         return 0;
 693 }
 694
 695 /*
 696  * Crypto capabilities of the server, where it says that
 697  * it supports or does not requested hash/cipher algorithms.
 698  */
 699 static int pohmelfs_crypto_cap_response(struct netfs_state *st)
 700 {
 701         struct netfs_cmd *cmd = &st->cmd;
 702         struct netfs_crypto_capabilities *cap;
 703         struct pohmelfs_sb *psb = st->psb;
 704         int err = 0;
 705
 706         if (cmd->size != sizeof(struct netfs_crypto_capabilities)) {
 707                 psb->flags = EPROTO;
 708                 wake_up(&psb->wait);
 709                 return -EPROTO;
 710         }
 711
 712         cap = st->data;
 713
 714         dprintk("%s: cipher '%s': %s, hash: '%s': %s.\n",
 715                         __func__,
 716                         psb->cipher_string, (cap->cipher_strlen) ? "SUPPORTED" : "NOT SUPPORTED",
 717                         psb->hash_string, (cap->hash_strlen) ? "SUPPORTED" : "NOT SUPPORTED");
 718
 719         if (!cap->hash_strlen) {
 720                 if (psb->hash_strlen && psb->crypto_fail_unsupported)
 721                         err = -ENOTSUPP;
 722                 psb->hash_strlen = 0;
 723                 kfree(psb->hash_string);
 724                 psb->hash_string = NULL;
 725         }
 726
 727         if (!cap->cipher_strlen) {
 728                 if (psb->cipher_strlen && psb->crypto_fail_unsupported)
 729                         err = -ENOTSUPP;
 730                 psb->cipher_strlen = 0;
 731                 kfree(psb->cipher_string);
 732                 psb->cipher_string = NULL;
 733         }
 734
 735         return err;
 736 }
 737
 738 /*
 739  * Capabilities handshake response.
 740  */
 741 static int pohmelfs_capabilities_response(struct netfs_state *st)
 742 {
 743         struct netfs_cmd *cmd = &st->cmd;
 744         int err = 0;
 745
 746         err = pohmelfs_data_recv(st, st->data, cmd->size);
 747         if (err)
 748                 return err;
 749
 750         switch (cmd->id) {
 751         case POHMELFS_CRYPTO_CAPABILITIES:
 752                         return pohmelfs_crypto_cap_response(st);
 753         case POHMELFS_ROOT_CAPABILITIES:
 754                         return pohmelfs_root_cap_response(st);
 755         default:
 756                         break;
 757         }
 758         return -EINVAL;
 759 }
 760
 761 /*
 762  * Receiving extended attribute.
 763  * Does not work properly if received size is more than requested one,
 764  * it should not happen with current request/reply model though.
 765  */
 766 static int pohmelfs_getxattr_response(struct netfs_state *st)
 767 {
 768         struct pohmelfs_sb *psb = st->psb;
 769         struct netfs_cmd *cmd = &st->cmd;
 770         struct pohmelfs_mcache *m;
 771         short error = (signed short)cmd->ext, err;
 772         unsigned int sz, total_size;
 773
 774         m = pohmelfs_mcache_search(psb, cmd->id);
 775
 776         dprintk("%s: id: %llu, gen: %llu, err: %d.\n",
 777                 __func__, cmd->id, (m) ? m->gen : 0, error);
 778
 779         if (!m) {
 780                 printk("%s: failed to find getxattr cache entry: id: %llu.\n", __func__, cmd->id);
 781                 return -ENOENT;
 782         }
 783
 784         if (cmd->size) {
 785                 sz = min_t(unsigned int, cmd->size, m->size);
 786                 err = pohmelfs_data_recv_and_check(st, m->data, sz);
 787                 if (err) {
 788                         error = err;
 789                         goto out;
 790                 }
 791
 792                 m->size = sz;
 793                 total_size = cmd->size - sz;
 794
 795                 while (total_size) {
 796                         sz = min(total_size, st->size);
 797
 798                         err = pohmelfs_data_recv_and_check(st, st->data, sz);
 799                         if (err) {
 800                                 error = err;
 801                                 break;
 802                         }
 803
 804                         total_size -= sz;
 805                 }
 806         }
 807
 808 out:
 809         m->err = error;
 810         complete(&m->complete);
 811         pohmelfs_mcache_put(psb, m);
 812
 813         return error;
 814 }
 815
 816 int pohmelfs_data_lock_response(struct netfs_state *st)
 817 {
 818         struct pohmelfs_sb *psb = st->psb;
 819         struct netfs_cmd *cmd = &st->cmd;
 820         struct pohmelfs_mcache *m;
 821         short err = (signed short)cmd->ext;
 822         u64 id = cmd->id;
 823
 824         m = pohmelfs_mcache_search(psb, id);
 825
 826         dprintk("%s: id: %llu, gen: %llu, err: %d.\n",
 827                 __func__, cmd->id, (m) ? m->gen : 0, err);
 828
 829         if (!m) {
 830                 pohmelfs_data_recv(st, st->data, cmd->size);
 831                 printk("%s: failed to find data lock response: id: %llu.\n", __func__, cmd->id);
 832                 return -ENOENT;
 833         }
 834
 835         if (cmd->size)
 836                 err = pohmelfs_data_recv_and_check(st, &m->info, cmd->size);
 837
 838         m->err = err;
 839         complete(&m->complete);
 840         pohmelfs_mcache_put(psb, m);
 841
 842         return err;
 843 }
 844
 845 static void __inline__ netfs_state_reset(struct netfs_state *st)
 846 {
 847         netfs_state_lock_send(st);
 848         netfs_state_exit(st);
 849         netfs_state_init(st);
 850         netfs_state_unlock_send(st);
 851 }
 852
 853 /*
 854  * Main receiving function, called from dedicated kernel thread.
 855  */
 856 static int pohmelfs_recv(void *data)
 857 {
 858         int err = -EINTR;
 859         struct netfs_state *st = data;
 860         struct netfs_cmd *cmd = &st->cmd;
 861
 862         while (!kthread_should_stop()) {
 863                 /*
 864                  * If socket will be reset after this statement, then
 865                  * pohmelfs_data_recv() will just fail and loop will
 866                  * start again, so it can be done without any locks.
 867                  *
 868                  * st->read_socket is needed to prevents state machine
 869                  * breaking between this data reading and subsequent one
 870                  * in protocol specific functions during connection reset.
 871                  * In case of reset we have to read next command and do
 872                  * not expect data for old command to magically appear in
 873                  * new connection.
 874                  */
 875                 st->read_socket = st->socket;
 876                 err = pohmelfs_data_recv(st, cmd, sizeof(struct netfs_cmd));
 877                 if (err) {
 878                         msleep(1000);
 879                         continue;
 880                 }
 881
 882                 netfs_convert_cmd(cmd);
 883
 884                 dprintk("%s: cmd: %u, id: %llu, start: %llu, size: %u, "
 885                                 "ext: %u, csize: %u, cpad: %u.\n",
 886                                 __func__, cmd->cmd, cmd->id, cmd->start,
 887                                 cmd->size, cmd->ext, cmd->csize, cmd->cpad);
 888
 889                 if (cmd->csize) {
 890                         struct pohmelfs_crypto_engine *e = &st->eng;
 891
 892                         if (unlikely(cmd->csize > e->size/2)) {
 893                                 netfs_state_reset(st);
 894                                 continue;
 895                         }
 896
 897                         if (e->hash && unlikely(cmd->csize != st->psb->crypto_attached_size)) {
 898                                 dprintk("%s: cmd: cmd: %u, id: %llu, start: %llu, size: %u, "
 899                                                 "csize: %u != digest size %u.\n",
 900                                                 __func__, cmd->cmd, cmd->id, cmd->start, cmd->size,
 901                                                 cmd->csize, st->psb->crypto_attached_size);
 902                                 netfs_state_reset(st);
 903                                 continue;
 904                         }
 905
 906                         err = pohmelfs_data_recv(st, e->data, cmd->csize);
 907                         if (err) {
 908                                 netfs_state_reset(st);
 909                                 continue;
 910                         }
 911
 912 #ifdef CONFIG_POHMELFS_DEBUG
 913                         {
 914                                 unsigned int i;
 915                                 unsigned char *hash = e->data;
 916
 917                                 dprintk("%s: received hash: ", __func__);
 918                                 for (i = 0; i < cmd->csize; ++i)
 919                                         printk("%02x ", hash[i]);
 920
 921                                 printk("\n");
 922                         }
 923 #endif
 924                         cmd->size -= cmd->csize;
 925                 }
 926
 927                 /*
 928                  * This should catch protocol breakage and random garbage instead of commands.
 929                  */
 930                 if (unlikely((cmd->size > st->size) && (cmd->cmd != NETFS_XATTR_GET))) {
 931                         netfs_state_reset(st);
 932                         continue;
 933                 }
 934
 935                 switch (cmd->cmd) {
 936                 case NETFS_READ_PAGE:
 937                                 err = pohmelfs_read_page_response(st);
 938                                 break;
 939                 case NETFS_READDIR:
 940                                 err = pohmelfs_readdir_response(st);
 941                                 break;
 942                 case NETFS_LOOKUP:
 943                                 err = pohmelfs_lookup_response(st);
 944                                 break;
 945                 case NETFS_CREATE:
 946                                 err = pohmelfs_create_response(st);
 947                                 break;
 948                 case NETFS_REMOVE:
 949                                 err = pohmelfs_remove_response(st);
 950                                 break;
 951                 case NETFS_TRANS:
 952                                 err = pohmelfs_transaction_response(st);
 953                                 break;
 954                 case NETFS_PAGE_CACHE:
 955                                 err = pohmelfs_page_cache_response(st);
 956                                 break;
 957                 case NETFS_CAPABILITIES:
 958                                 err = pohmelfs_capabilities_response(st);
 959                                 break;
 960                 case NETFS_LOCK:
 961                                 err = pohmelfs_data_lock_response(st);
 962                                 break;
 963                 case NETFS_XATTR_GET:
 964                                 err = pohmelfs_getxattr_response(st);
 965                                 break;
 966                 default:
 967                                 printk("%s: wrong cmd: %u, id: %llu, start: %llu, size: %u, ext: %u.\n",
 968                                         __func__, cmd->cmd, cmd->id, cmd->start, cmd->size, cmd->ext);
 969                                 netfs_state_reset(st);
 970                                 break;
 971                 }
 972         }
 973
 974         while (!kthread_should_stop())
 975                 schedule_timeout_uninterruptible(msecs_to_jiffies(10));
 976
 977         return err;
 978 }
 979
 980 int netfs_state_init(struct netfs_state *st)
 981 {
 982         int err;
 983         struct pohmelfs_ctl *ctl = &st->ctl;
 984
 985         err = sock_create(ctl->addr.sa_family, ctl->type, ctl->proto, &st->socket);
 986         if (err) {
 987                 printk("%s: failed to create a socket: family: %d, type: %d, proto: %d, err: %d.\n",
 988                                 __func__, ctl->addr.sa_family, ctl->type, ctl->proto, err);
 989                 goto err_out_exit;
 990         }
 991
 992         st->socket->sk->sk_allocation = GFP_NOIO;
 993         st->socket->sk->sk_sndtimeo = st->socket->sk->sk_rcvtimeo = msecs_to_jiffies(60000);
 994
 995         err = kernel_connect(st->socket, (struct sockaddr *)&ctl->addr, ctl->addrlen, 0);
 996         if (err) {
 997                 printk("%s: failed to connect to server: idx: %u, err: %d.\n",
 998                                 __func__, st->psb->idx, err);
 999                 goto err_out_release;
1000         }
1001         st->socket->sk->sk_sndtimeo = st->socket->sk->sk_rcvtimeo = msecs_to_jiffies(60000);
1002
1003         err = netfs_poll_init(st);
1004         if (err)
1005                 goto err_out_release;
1006
1007         if (st->socket->ops->family == AF_INET) {
1008                 struct sockaddr_in *sin = (struct sockaddr_in *)&ctl->addr;
1009                 printk(KERN_INFO "%s: (re)connected to peer %pi4:%d.\n", __func__,
1010                         &sin->sin_addr.s_addr, ntohs(sin->sin_port));
1011         } else if (st->socket->ops->family == AF_INET6) {
1012                 struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&ctl->addr;
1013                 printk(KERN_INFO "%s: (re)connected to peer %pi6:%d", __func__,
1014                                 &sin->sin6_addr, ntohs(sin->sin6_port));
1015         }
1016
1017         return 0;
1018
1019 err_out_release:
1020         sock_release(st->socket);
1021 err_out_exit:
1022         st->socket = NULL;
1023         return err;
1024 }
1025
1026 void netfs_state_exit(struct netfs_state *st)
1027 {
1028         if (st->socket) {
1029                 netfs_poll_exit(st);
1030                 st->socket->ops->shutdown(st->socket, 2);
1031
1032                 if (st->socket->ops->family == AF_INET) {
1033                         struct sockaddr_in *sin = (struct sockaddr_in *)&st->ctl.addr;
1034                         printk(KERN_INFO "%s: disconnected from peer %pi4:%d.\n", __func__,
1035                                 &sin->sin_addr.s_addr, ntohs(sin->sin_port));
1036                 } else if (st->socket->ops->family == AF_INET6) {
1037                         struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&st->ctl.addr;
1038                         printk(KERN_INFO "%s: disconnected from peer %pi6:%d", __func__,
1039                                 &sin->sin6_addr, ntohs(sin->sin6_port));
1040                 }
1041
1042                 sock_release(st->socket);
1043                 st->socket = NULL;
1044                 st->read_socket = NULL;
1045                 st->need_reset = 0;
1046         }
1047 }
1048
1049 int pohmelfs_state_init_one(struct pohmelfs_sb *psb, struct pohmelfs_config *conf)
1050 {
1051         struct netfs_state *st = &conf->state;
1052         int err = -ENOMEM;
1053
1054         mutex_init(&st->__state_lock);
1055         mutex_init(&st->__state_send_lock);
1056         init_waitqueue_head(&st->thread_wait);
1057
1058         st->psb = psb;
1059         st->trans_root = RB_ROOT;
1060         mutex_init(&st->trans_lock);
1061
1062         st->size = psb->trans_data_size;
1063         st->data = kmalloc(st->size, GFP_KERNEL);
1064         if (!st->data)
1065                 goto err_out_exit;
1066
1067         if (psb->perform_crypto) {
1068                 err = pohmelfs_crypto_engine_init(&st->eng, psb);
1069                 if (err)
1070                         goto err_out_free_data;
1071         }
1072
1073         err = netfs_state_init(st);
1074         if (err)
1075                 goto err_out_free_engine;
1076
1077         st->thread = kthread_run(pohmelfs_recv, st, "pohmelfs/%u", psb->idx);
1078         if (IS_ERR(st->thread)) {
1079                 err = PTR_ERR(st->thread);
1080                 goto err_out_netfs_exit;
1081         }
1082
1083         if (!psb->active_state)
1084                 psb->active_state = conf;
1085
1086         dprintk("%s: conf: %p, st: %p, socket: %p.\n",
1087                         __func__, conf, st, st->socket);
1088         return 0;
1089
1090 err_out_netfs_exit:
1091         netfs_state_exit(st);
1092 err_out_free_engine:
1093         pohmelfs_crypto_engine_exit(&st->eng);
1094 err_out_free_data:
1095         kfree(st->data);
1096 err_out_exit:
1097         return err;
1098
1099 }
1100
1101 void pohmelfs_state_flush_transactions(struct netfs_state *st)
1102 {
1103         struct rb_node *rb_node;
1104         struct netfs_trans_dst *dst;
1105
1106         mutex_lock(&st->trans_lock);
1107         for (rb_node = rb_first(&st->trans_root); rb_node; ) {
1108                 dst = rb_entry(rb_node, struct netfs_trans_dst, state_entry);
1109                 rb_node = rb_next(rb_node);
1110
1111                 dst->trans->result = -EINVAL;
1112                 netfs_trans_remove_nolock(dst, st);
1113                 netfs_trans_drop_dst_nostate(dst);
1114         }
1115         mutex_unlock(&st->trans_lock);
1116 }
1117
1118 static void pohmelfs_state_exit_one(struct pohmelfs_config *c)
1119 {
1120         struct netfs_state *st = &c->state;
1121
1122         dprintk("%s: exiting, st: %p.\n", __func__, st);
1123         if (st->thread) {
1124                 kthread_stop(st->thread);
1125                 st->thread = NULL;
1126         }
1127
1128         netfs_state_lock_send(st);
1129         netfs_state_exit(st);
1130         netfs_state_unlock_send(st);
1131
1132         pohmelfs_state_flush_transactions(st);
1133
1134         pohmelfs_crypto_engine_exit(&st->eng);
1135         kfree(st->data);
1136
1137         kfree(c);
1138 }
1139
1140 /*
1141  * Initialize network stack. It searches for given ID in global
1142  * configuration table, this contains information of the remote server
1143  * (address (any supported by socket interface) and port, protocol and so on).
1144  */
1145 int pohmelfs_state_init(struct pohmelfs_sb *psb)
1146 {
1147         int err = -ENOMEM;
1148
1149         err = pohmelfs_copy_config(psb);
1150         if (err) {
1151                 pohmelfs_state_exit(psb);
1152                 return err;
1153         }
1154
1155         return 0;
1156 }
1157
1158 void pohmelfs_state_exit(struct pohmelfs_sb *psb)
1159 {
1160         struct pohmelfs_config *c, *tmp;
1161
1162         list_for_each_entry_safe(c, tmp, &psb->state_list, config_entry) {
1163                 list_del(&c->config_entry);
1164                 pohmelfs_state_exit_one(c);
1165         }
1166 }
1167
1168 void pohmelfs_switch_active(struct pohmelfs_sb *psb)
1169 {
1170         struct pohmelfs_config *c = psb->active_state;
1171
1172         if (!list_empty(&psb->state_list)) {
1173                 if (c->config_entry.next != &psb->state_list) {
1174                         psb->active_state = list_entry(c->config_entry.next,
1175                                 struct pohmelfs_config, config_entry);
1176                 } else {
1177                         psb->active_state = list_entry(psb->state_list.next,
1178                                 struct pohmelfs_config, config_entry);
1179                 }
1180
1181                 dprintk("%s: empty: %d, active %p -> %p.\n",
1182                         __func__, list_empty(&psb->state_list), c,
1183                         psb->active_state);
1184         } else
1185                 psb->active_state = NULL;
1186 }
1187
1188 void pohmelfs_check_states(struct pohmelfs_sb *psb)
1189 {
1190         struct pohmelfs_config *c, *tmp;
1191         LIST_HEAD(delete_list);
1192
1193         mutex_lock(&psb->state_lock);
1194         list_for_each_entry_safe(c, tmp, &psb->state_list, config_entry) {
1195                 if (pohmelfs_config_check(c, psb->idx)) {
1196
1197                         if (psb->active_state == c)
1198                                 pohmelfs_switch_active(psb);
1199                         list_move(&c->config_entry, &delete_list);
1200                 }
1201         }
1202         pohmelfs_copy_config(psb);
1203         mutex_unlock(&psb->state_lock);
1204
1205         list_for_each_entry_safe(c, tmp, &delete_list, config_entry) {
1206                 list_del(&c->config_entry);
1207                 pohmelfs_state_exit_one(c);
1208         }
1209 }