drivers/block/rnbd/rnbd-srv.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RDMA Network Block Driver
   4  *
   5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
   6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
   7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
   8  */
   9 #undef pr_fmt
  10 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
  11
  12 #include <linux/module.h>
  13 #include <linux/blkdev.h>
  14
  15 #include "rnbd-srv.h"
  16 #include "rnbd-srv-trace.h"
  17
  18 MODULE_DESCRIPTION("RDMA Network Block Device Server");
  19 MODULE_LICENSE("GPL");
  20
  21 static u16 port_nr = RTRS_PORT;
  22
  23 module_param_named(port_nr, port_nr, ushort, 0444);
  24 MODULE_PARM_DESC(port_nr,
  25                  "The port number the server is listening on (default: "
  26                  __stringify(RTRS_PORT)")");
  27
  28 #define DEFAULT_DEV_SEARCH_PATH "/"
  29
  30 static char dev_search_path[PATH_MAX] = DEFAULT_DEV_SEARCH_PATH;
  31
  32 static int dev_search_path_set(const char *val, const struct kernel_param *kp)
  33 {
  34         const char *p = strrchr(val, '\n') ? : val + strlen(val);
  35
  36         if (strlen(val) >= sizeof(dev_search_path))
  37                 return -EINVAL;
  38
  39         snprintf(dev_search_path, sizeof(dev_search_path), "%.*s",
  40                  (int)(p - val), val);
  41
  42         pr_info("dev_search_path changed to '%s'\n", dev_search_path);
  43
  44         return 0;
  45 }
  46
  47 static struct kparam_string dev_search_path_kparam_str = {
  48         .maxlen = sizeof(dev_search_path),
  49         .string = dev_search_path
  50 };
  51
  52 static const struct kernel_param_ops dev_search_path_ops = {
  53         .set    = dev_search_path_set,
  54         .get    = param_get_string,
  55 };
  56
  57 module_param_cb(dev_search_path, &dev_search_path_ops,
  58                 &dev_search_path_kparam_str, 0444);
  59 MODULE_PARM_DESC(dev_search_path,
  60                  "Sets the dev_search_path. When a device is mapped this path is prepended to the device path from the map device operation.  If %SESSNAME% is specified in a path, then device will be searched in a session namespace. (default: "
  61                  DEFAULT_DEV_SEARCH_PATH ")");
  62
  63 static DEFINE_MUTEX(sess_lock);
  64 static DEFINE_SPINLOCK(dev_lock);
  65
  66 static LIST_HEAD(sess_list);
  67 static LIST_HEAD(dev_list);
  68
  69 struct rnbd_io_private {
  70         struct rtrs_srv_op              *id;
  71         struct rnbd_srv_sess_dev        *sess_dev;
  72 };
  73
  74 static void rnbd_sess_dev_release(struct kref *kref)
  75 {
  76         struct rnbd_srv_sess_dev *sess_dev;
  77
  78         sess_dev = container_of(kref, struct rnbd_srv_sess_dev, kref);
  79         complete(sess_dev->destroy_comp);
  80 }
  81
  82 static inline void rnbd_put_sess_dev(struct rnbd_srv_sess_dev *sess_dev)
  83 {
  84         kref_put(&sess_dev->kref, rnbd_sess_dev_release);
  85 }
  86
  87 static struct rnbd_srv_sess_dev *
  88 rnbd_get_sess_dev(int dev_id, struct rnbd_srv_session *srv_sess)
  89 {
  90         struct rnbd_srv_sess_dev *sess_dev;
  91         int ret = 0;
  92
  93         rcu_read_lock();
  94         sess_dev = xa_load(&srv_sess->index_idr, dev_id);
  95         if (sess_dev)
  96                 ret = kref_get_unless_zero(&sess_dev->kref);
  97         rcu_read_unlock();
  98
  99         if (!ret)
 100                 return ERR_PTR(-ENXIO);
 101
 102         return sess_dev;
 103 }
 104
 105 static void rnbd_dev_bi_end_io(struct bio *bio)
 106 {
 107         struct rnbd_io_private *rnbd_priv = bio->bi_private;
 108         struct rnbd_srv_sess_dev *sess_dev = rnbd_priv->sess_dev;
 109
 110         rnbd_put_sess_dev(sess_dev);
 111         rtrs_srv_resp_rdma(rnbd_priv->id, blk_status_to_errno(bio->bi_status));
 112
 113         kfree(rnbd_priv);
 114         bio_put(bio);
 115 }
 116
 117 static int process_rdma(struct rnbd_srv_session *srv_sess,
 118                         struct rtrs_srv_op *id, void *data, u32 datalen,
 119                         const void *usr, size_t usrlen)
 120 {
 121         const struct rnbd_msg_io *msg = usr;
 122         struct rnbd_io_private *priv;
 123         struct rnbd_srv_sess_dev *sess_dev;
 124         u32 dev_id;
 125         int err;
 126         struct bio *bio;
 127         short prio;
 128
 129         trace_process_rdma(srv_sess, msg, id, datalen, usrlen);
 130
 131         priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 132         if (!priv)
 133                 return -ENOMEM;
 134
 135         dev_id = le32_to_cpu(msg->device_id);
 136
 137         sess_dev = rnbd_get_sess_dev(dev_id, srv_sess);
 138         if (IS_ERR(sess_dev)) {
 139                 pr_err_ratelimited("Got I/O request on session %s for unknown device id %d: %pe\n",
 140                                    srv_sess->sessname, dev_id, sess_dev);
 141                 err = -ENOTCONN;
 142                 goto err;
 143         }
 144
 145         priv->sess_dev = sess_dev;
 146         priv->id = id;
 147
 148         bio = bio_alloc(file_bdev(sess_dev->bdev_file), 1,
 149                         rnbd_to_bio_flags(le32_to_cpu(msg->rw)), GFP_KERNEL);
 150         if (bio_add_page(bio, virt_to_page(data), datalen,
 151                         offset_in_page(data)) != datalen) {
 152                 rnbd_srv_err_rl(sess_dev, "Failed to map data to bio\n");
 153                 err = -EINVAL;
 154                 goto bio_put;
 155         }
 156
 157         bio->bi_opf = rnbd_to_bio_flags(le32_to_cpu(msg->rw));
 158         if (bio_has_data(bio) &&
 159             bio->bi_iter.bi_size != le32_to_cpu(msg->bi_size)) {
 160                 rnbd_srv_err_rl(sess_dev, "Datalen mismatch:  bio bi_size (%u), bi_size (%u)\n",
 161                                 bio->bi_iter.bi_size, msg->bi_size);
 162                 err = -EINVAL;
 163                 goto bio_put;
 164         }
 165         bio->bi_end_io = rnbd_dev_bi_end_io;
 166         bio->bi_private = priv;
 167         bio->bi_iter.bi_sector = le64_to_cpu(msg->sector);
 168         prio = srv_sess->ver < RNBD_PROTO_VER_MAJOR ||
 169                usrlen < sizeof(*msg) ? 0 : le16_to_cpu(msg->prio);
 170         bio_set_prio(bio, prio);
 171
 172         submit_bio(bio);
 173
 174         return 0;
 175
 176 bio_put:
 177         bio_put(bio);
 178         rnbd_put_sess_dev(sess_dev);
 179 err:
 180         kfree(priv);
 181         return err;
 182 }
 183
 184 static void destroy_device(struct kref *kref)
 185 {
 186         struct rnbd_srv_dev *dev = container_of(kref, struct rnbd_srv_dev, kref);
 187
 188         WARN_ONCE(!list_empty(&dev->sess_dev_list),
 189                   "Device %s is being destroyed but still in use!\n",
 190                   dev->name);
 191
 192         spin_lock(&dev_lock);
 193         list_del(&dev->list);
 194         spin_unlock(&dev_lock);
 195
 196         mutex_destroy(&dev->lock);
 197         if (dev->dev_kobj.state_in_sysfs)
 198                 /*
 199                  * Destroy kobj only if it was really created.
 200                  */
 201                 rnbd_srv_destroy_dev_sysfs(dev);
 202         else
 203                 kfree(dev);
 204 }
 205
 206 static void rnbd_put_srv_dev(struct rnbd_srv_dev *dev)
 207 {
 208         kref_put(&dev->kref, destroy_device);
 209 }
 210
 211 void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id)
 212 {
 213         DECLARE_COMPLETION_ONSTACK(dc);
 214
 215         if (keep_id)
 216                 /* free the resources for the id but don't  */
 217                 /* allow to re-use the id itself because it */
 218                 /* is still used by the client              */
 219                 xa_cmpxchg(&sess_dev->sess->index_idr, sess_dev->device_id,
 220                            sess_dev, NULL, 0);
 221         else
 222                 xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
 223         synchronize_rcu();
 224
 225         sess_dev->destroy_comp = &dc;
 226         rnbd_put_sess_dev(sess_dev);
 227         wait_for_completion(&dc); /* wait for inflights to drop to zero */
 228
 229         fput(sess_dev->bdev_file);
 230         mutex_lock(&sess_dev->dev->lock);
 231         list_del(&sess_dev->dev_list);
 232         if (!sess_dev->readonly)
 233                 sess_dev->dev->open_write_cnt--;
 234         mutex_unlock(&sess_dev->dev->lock);
 235
 236         rnbd_put_srv_dev(sess_dev->dev);
 237
 238         rnbd_srv_info(sess_dev, "Device closed\n");
 239         kfree(sess_dev);
 240 }
 241
 242 static void destroy_sess(struct rnbd_srv_session *srv_sess)
 243 {
 244         struct rnbd_srv_sess_dev *sess_dev;
 245         unsigned long index;
 246
 247         if (xa_empty(&srv_sess->index_idr))
 248                 goto out;
 249
 250         trace_destroy_sess(srv_sess);
 251
 252         mutex_lock(&srv_sess->lock);
 253         xa_for_each(&srv_sess->index_idr, index, sess_dev)
 254                 rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 255         mutex_unlock(&srv_sess->lock);
 256
 257 out:
 258         xa_destroy(&srv_sess->index_idr);
 259
 260         pr_info("RTRS Session %s disconnected\n", srv_sess->sessname);
 261
 262         mutex_lock(&sess_lock);
 263         list_del(&srv_sess->list);
 264         mutex_unlock(&sess_lock);
 265
 266         mutex_destroy(&srv_sess->lock);
 267         kfree(srv_sess);
 268 }
 269
 270 static int create_sess(struct rtrs_srv_sess *rtrs)
 271 {
 272         struct rnbd_srv_session *srv_sess;
 273         char pathname[NAME_MAX];
 274         int err;
 275
 276         err = rtrs_srv_get_path_name(rtrs, pathname, sizeof(pathname));
 277         if (err) {
 278                 pr_err("rtrs_srv_get_path_name(%s): %d\n", pathname, err);
 279
 280                 return err;
 281         }
 282         srv_sess = kzalloc(sizeof(*srv_sess), GFP_KERNEL);
 283         if (!srv_sess)
 284                 return -ENOMEM;
 285
 286         srv_sess->queue_depth = rtrs_srv_get_queue_depth(rtrs);
 287         xa_init_flags(&srv_sess->index_idr, XA_FLAGS_ALLOC);
 288         mutex_init(&srv_sess->lock);
 289         mutex_lock(&sess_lock);
 290         list_add(&srv_sess->list, &sess_list);
 291         mutex_unlock(&sess_lock);
 292
 293         srv_sess->rtrs = rtrs;
 294         strscpy(srv_sess->sessname, pathname, sizeof(srv_sess->sessname));
 295
 296         rtrs_srv_set_sess_priv(rtrs, srv_sess);
 297
 298         trace_create_sess(srv_sess);
 299
 300         return 0;
 301 }
 302
 303 static int rnbd_srv_link_ev(struct rtrs_srv_sess *rtrs,
 304                              enum rtrs_srv_link_ev ev, void *priv)
 305 {
 306         struct rnbd_srv_session *srv_sess = priv;
 307
 308         switch (ev) {
 309         case RTRS_SRV_LINK_EV_CONNECTED:
 310                 return create_sess(rtrs);
 311
 312         case RTRS_SRV_LINK_EV_DISCONNECTED:
 313                 if (WARN_ON_ONCE(!srv_sess))
 314                         return -EINVAL;
 315
 316                 destroy_sess(srv_sess);
 317                 return 0;
 318
 319         default:
 320                 pr_warn("Received unknown RTRS session event %d from session %s\n",
 321                         ev, srv_sess->sessname);
 322                 return -EINVAL;
 323         }
 324 }
 325
 326 void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
 327                                    struct kobj_attribute *attr)
 328 {
 329         struct rnbd_srv_session *sess = sess_dev->sess;
 330
 331         /* It is already started to close by client's close message. */
 332         if (!mutex_trylock(&sess->lock))
 333                 return;
 334
 335         sess_dev->keep_id = true;
 336         /* first remove sysfs itself to avoid deadlock */
 337         sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
 338         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 339         mutex_unlock(&sess->lock);
 340 }
 341
 342 static void process_msg_close(struct rnbd_srv_session *srv_sess,
 343                              void *data, size_t datalen, const void *usr,
 344                              size_t usrlen)
 345 {
 346         const struct rnbd_msg_close *close_msg = usr;
 347         struct rnbd_srv_sess_dev *sess_dev;
 348
 349         trace_process_msg_close(srv_sess, close_msg);
 350
 351         sess_dev = rnbd_get_sess_dev(le32_to_cpu(close_msg->device_id),
 352                                       srv_sess);
 353         if (IS_ERR(sess_dev))
 354                 return;
 355
 356         rnbd_put_sess_dev(sess_dev);
 357         mutex_lock(&srv_sess->lock);
 358         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 359         mutex_unlock(&srv_sess->lock);
 360 }
 361
 362 static int process_msg_open(struct rnbd_srv_session *srv_sess,
 363                             const void *msg, size_t len,
 364                             void *data, size_t datalen);
 365
 366 static void process_msg_sess_info(struct rnbd_srv_session *srv_sess,
 367                                  const void *msg, size_t len,
 368                                  void *data, size_t datalen);
 369
 370 static int rnbd_srv_rdma_ev(void *priv, struct rtrs_srv_op *id,
 371                             void *data, size_t datalen,
 372                             const void *usr, size_t usrlen)
 373 {
 374         struct rnbd_srv_session *srv_sess = priv;
 375         const struct rnbd_msg_hdr *hdr = usr;
 376         int ret = 0;
 377         u16 type;
 378
 379         if (WARN_ON_ONCE(!srv_sess))
 380                 return -ENODEV;
 381
 382         type = le16_to_cpu(hdr->type);
 383
 384         switch (type) {
 385         case RNBD_MSG_IO:
 386                 return process_rdma(srv_sess, id, data, datalen, usr, usrlen);
 387         case RNBD_MSG_CLOSE:
 388                 process_msg_close(srv_sess, data, datalen, usr, usrlen);
 389                 break;
 390         case RNBD_MSG_OPEN:
 391                 ret = process_msg_open(srv_sess, usr, usrlen, data, datalen);
 392                 break;
 393         case RNBD_MSG_SESS_INFO:
 394                 process_msg_sess_info(srv_sess, usr, usrlen, data, datalen);
 395                 break;
 396         default:
 397                 pr_warn("Received unexpected message type %d from session %s\n",
 398                         type, srv_sess->sessname);
 399                 return -EINVAL;
 400         }
 401
 402         /*
 403          * Since ret is passed to rtrs to handle the failure case, we
 404          * just return 0 at the end otherwise callers in rtrs would call
 405          * send_io_resp_imm again to print redundant err message.
 406          */
 407         rtrs_srv_resp_rdma(id, ret);
 408         return 0;
 409 }
 410
 411 static struct rnbd_srv_sess_dev
 412 *rnbd_sess_dev_alloc(struct rnbd_srv_session *srv_sess)
 413 {
 414         struct rnbd_srv_sess_dev *sess_dev;
 415         int error;
 416
 417         sess_dev = kzalloc(sizeof(*sess_dev), GFP_KERNEL);
 418         if (!sess_dev)
 419                 return ERR_PTR(-ENOMEM);
 420
 421         error = xa_alloc(&srv_sess->index_idr, &sess_dev->device_id, sess_dev,
 422                          xa_limit_32b, GFP_NOWAIT);
 423         if (error < 0) {
 424                 pr_warn("Allocating idr failed, err: %d\n", error);
 425                 kfree(sess_dev);
 426                 return ERR_PTR(error);
 427         }
 428
 429         return sess_dev;
 430 }
 431
 432 static struct rnbd_srv_dev *rnbd_srv_init_srv_dev(struct block_device *bdev)
 433 {
 434         struct rnbd_srv_dev *dev;
 435
 436         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 437         if (!dev)
 438                 return ERR_PTR(-ENOMEM);
 439
 440         snprintf(dev->name, sizeof(dev->name), "%pg", bdev);
 441         kref_init(&dev->kref);
 442         INIT_LIST_HEAD(&dev->sess_dev_list);
 443         mutex_init(&dev->lock);
 444
 445         return dev;
 446 }
 447
 448 static struct rnbd_srv_dev *
 449 rnbd_srv_find_or_add_srv_dev(struct rnbd_srv_dev *new_dev)
 450 {
 451         struct rnbd_srv_dev *dev;
 452
 453         spin_lock(&dev_lock);
 454         list_for_each_entry(dev, &dev_list, list) {
 455                 if (!strncmp(dev->name, new_dev->name, sizeof(dev->name))) {
 456                         if (!kref_get_unless_zero(&dev->kref))
 457                                 /*
 458                                  * We lost the race, device is almost dead.
 459                                  *  Continue traversing to find a valid one.
 460                                  */
 461                                 continue;
 462                         spin_unlock(&dev_lock);
 463                         return dev;
 464                 }
 465         }
 466         list_add(&new_dev->list, &dev_list);
 467         spin_unlock(&dev_lock);
 468
 469         return new_dev;
 470 }
 471
 472 static int rnbd_srv_check_update_open_perm(struct rnbd_srv_dev *srv_dev,
 473                                             struct rnbd_srv_session *srv_sess,
 474                                             enum rnbd_access_mode access_mode)
 475 {
 476         int ret = 0;
 477
 478         mutex_lock(&srv_dev->lock);
 479
 480         switch (access_mode) {
 481         case RNBD_ACCESS_RO:
 482                 break;
 483         case RNBD_ACCESS_RW:
 484                 if (srv_dev->open_write_cnt == 0)  {
 485                         srv_dev->open_write_cnt++;
 486                 } else {
 487                         pr_err("Mapping device '%s' for session %s with RW permissions failed. Device already opened as 'RW' by %d client(s), access mode %s.\n",
 488                                srv_dev->name, srv_sess->sessname,
 489                                srv_dev->open_write_cnt,
 490                                rnbd_access_modes[access_mode].str);
 491                         ret = -EPERM;
 492                 }
 493                 break;
 494         case RNBD_ACCESS_MIGRATION:
 495                 if (srv_dev->open_write_cnt < 2) {
 496                         srv_dev->open_write_cnt++;
 497                 } else {
 498                         pr_err("Mapping device '%s' for session %s with migration permissions failed. Device already opened as 'RW' by %d client(s), access mode %s.\n",
 499                                srv_dev->name, srv_sess->sessname,
 500                                srv_dev->open_write_cnt,
 501                                rnbd_access_modes[access_mode].str);
 502                         ret = -EPERM;
 503                 }
 504                 break;
 505         default:
 506                 pr_err("Received mapping request for device '%s' on session %s with invalid access mode: %d\n",
 507                        srv_dev->name, srv_sess->sessname, access_mode);
 508                 ret = -EINVAL;
 509         }
 510
 511         mutex_unlock(&srv_dev->lock);
 512
 513         return ret;
 514 }
 515
 516 static struct rnbd_srv_dev *
 517 rnbd_srv_get_or_create_srv_dev(struct block_device *bdev,
 518                                 struct rnbd_srv_session *srv_sess,
 519                                 enum rnbd_access_mode access_mode)
 520 {
 521         int ret;
 522         struct rnbd_srv_dev *new_dev, *dev;
 523
 524         new_dev = rnbd_srv_init_srv_dev(bdev);
 525         if (IS_ERR(new_dev))
 526                 return new_dev;
 527
 528         dev = rnbd_srv_find_or_add_srv_dev(new_dev);
 529         if (dev != new_dev)
 530                 kfree(new_dev);
 531
 532         ret = rnbd_srv_check_update_open_perm(dev, srv_sess, access_mode);
 533         if (ret) {
 534                 rnbd_put_srv_dev(dev);
 535                 return ERR_PTR(ret);
 536         }
 537
 538         return dev;
 539 }
 540
 541 static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
 542                                         struct rnbd_srv_sess_dev *sess_dev)
 543 {
 544         struct block_device *bdev = file_bdev(sess_dev->bdev_file);
 545
 546         rsp->hdr.type = cpu_to_le16(RNBD_MSG_OPEN_RSP);
 547         rsp->device_id = cpu_to_le32(sess_dev->device_id);
 548         rsp->nsectors = cpu_to_le64(bdev_nr_sectors(bdev));
 549         rsp->logical_block_size = cpu_to_le16(bdev_logical_block_size(bdev));
 550         rsp->physical_block_size = cpu_to_le16(bdev_physical_block_size(bdev));
 551         rsp->max_segments = cpu_to_le16(bdev_max_segments(bdev));
 552         rsp->max_hw_sectors =
 553                 cpu_to_le32(queue_max_hw_sectors(bdev_get_queue(bdev)));
 554         rsp->max_write_zeroes_sectors =
 555                 cpu_to_le32(bdev_write_zeroes_sectors(bdev));
 556         rsp->max_discard_sectors = cpu_to_le32(bdev_max_discard_sectors(bdev));
 557         rsp->discard_granularity = cpu_to_le32(bdev_discard_granularity(bdev));
 558         rsp->discard_alignment = cpu_to_le32(bdev_discard_alignment(bdev));
 559         rsp->secure_discard = cpu_to_le16(bdev_max_secure_erase_sectors(bdev));
 560         rsp->cache_policy = 0;
 561         if (bdev_write_cache(bdev))
 562                 rsp->cache_policy |= RNBD_WRITEBACK;
 563         if (bdev_fua(bdev))
 564                 rsp->cache_policy |= RNBD_FUA;
 565 }
 566
 567 static struct rnbd_srv_sess_dev *
 568 rnbd_srv_create_set_sess_dev(struct rnbd_srv_session *srv_sess,
 569                               const struct rnbd_msg_open *open_msg,
 570                               struct file *bdev_file, bool readonly,
 571                               struct rnbd_srv_dev *srv_dev)
 572 {
 573         struct rnbd_srv_sess_dev *sdev = rnbd_sess_dev_alloc(srv_sess);
 574
 575         if (IS_ERR(sdev))
 576                 return sdev;
 577
 578         kref_init(&sdev->kref);
 579
 580         strscpy(sdev->pathname, open_msg->dev_name, sizeof(sdev->pathname));
 581
 582         sdev->bdev_file         = bdev_file;
 583         sdev->sess              = srv_sess;
 584         sdev->dev               = srv_dev;
 585         sdev->readonly          = readonly;
 586         sdev->access_mode       = open_msg->access_mode;
 587
 588         return sdev;
 589 }
 590
 591 static char *rnbd_srv_get_full_path(struct rnbd_srv_session *srv_sess,
 592                                      const char *dev_name)
 593 {
 594         char *full_path;
 595         char *a, *b;
 596         int len;
 597
 598         full_path = kmalloc(PATH_MAX, GFP_KERNEL);
 599         if (!full_path)
 600                 return ERR_PTR(-ENOMEM);
 601
 602         /*
 603          * Replace %SESSNAME% with a real session name in order to
 604          * create device namespace.
 605          */
 606         a = strnstr(dev_search_path, "%SESSNAME%", sizeof(dev_search_path));
 607         if (a) {
 608                 len = a - dev_search_path;
 609
 610                 len = snprintf(full_path, PATH_MAX, "%.*s/%s/%s", len,
 611                                dev_search_path, srv_sess->sessname, dev_name);
 612         } else {
 613                 len = snprintf(full_path, PATH_MAX, "%s/%s",
 614                                dev_search_path, dev_name);
 615         }
 616         if (len >= PATH_MAX) {
 617                 pr_err("Too long path: %s, %s, %s\n",
 618                        dev_search_path, srv_sess->sessname, dev_name);
 619                 kfree(full_path);
 620                 return ERR_PTR(-EINVAL);
 621         }
 622
 623         /* eliminitate duplicated slashes */
 624         a = strchr(full_path, '/');
 625         b = a;
 626         while (*b != '\0') {
 627                 if (*b == '/' && *a == '/') {
 628                         b++;
 629                 } else {
 630                         a++;
 631                         *a = *b;
 632                         b++;
 633                 }
 634         }
 635         a++;
 636         *a = '\0';
 637
 638         return full_path;
 639 }
 640
 641 static void process_msg_sess_info(struct rnbd_srv_session *srv_sess,
 642                                  const void *msg, size_t len,
 643                                  void *data, size_t datalen)
 644 {
 645         const struct rnbd_msg_sess_info *sess_info_msg = msg;
 646         struct rnbd_msg_sess_info_rsp *rsp = data;
 647
 648         srv_sess->ver = min_t(u8, sess_info_msg->ver, RNBD_PROTO_VER_MAJOR);
 649
 650         trace_process_msg_sess_info(srv_sess, sess_info_msg);
 651
 652         rsp->hdr.type = cpu_to_le16(RNBD_MSG_SESS_INFO_RSP);
 653         rsp->ver = srv_sess->ver;
 654 }
 655
 656 /**
 657  * find_srv_sess_dev() - a dev is already opened by this name
 658  * @srv_sess:   the session to search.
 659  * @dev_name:   string containing the name of the device.
 660  *
 661  * Return struct rnbd_srv_sess_dev if srv_sess already opened the dev_name
 662  * NULL if the session didn't open the device yet.
 663  */
 664 static struct rnbd_srv_sess_dev *
 665 find_srv_sess_dev(struct rnbd_srv_session *srv_sess, const char *dev_name)
 666 {
 667         struct rnbd_srv_sess_dev *sess_dev;
 668         unsigned long index;
 669
 670         if (xa_empty(&srv_sess->index_idr))
 671                 return NULL;
 672
 673         xa_for_each(&srv_sess->index_idr, index, sess_dev)
 674                 if (!strcmp(sess_dev->pathname, dev_name))
 675                         return sess_dev;
 676
 677         return NULL;
 678 }
 679
 680 static int process_msg_open(struct rnbd_srv_session *srv_sess,
 681                             const void *msg, size_t len,
 682                             void *data, size_t datalen)
 683 {
 684         int ret;
 685         struct rnbd_srv_dev *srv_dev;
 686         struct rnbd_srv_sess_dev *srv_sess_dev;
 687         const struct rnbd_msg_open *open_msg = msg;
 688         struct file *bdev_file;
 689         blk_mode_t open_flags = BLK_OPEN_READ;
 690         char *full_path;
 691         struct rnbd_msg_open_rsp *rsp = data;
 692
 693         trace_process_msg_open(srv_sess, open_msg);
 694
 695         if (open_msg->access_mode != RNBD_ACCESS_RO)
 696                 open_flags |= BLK_OPEN_WRITE;
 697
 698         mutex_lock(&srv_sess->lock);
 699
 700         srv_sess_dev = find_srv_sess_dev(srv_sess, open_msg->dev_name);
 701         if (srv_sess_dev)
 702                 goto fill_response;
 703
 704         if ((strlen(dev_search_path) + strlen(open_msg->dev_name))
 705             >= PATH_MAX) {
 706                 pr_err("Opening device for session %s failed, device path too long. '%s/%s' is longer than PATH_MAX (%d)\n",
 707                        srv_sess->sessname, dev_search_path, open_msg->dev_name,
 708                        PATH_MAX);
 709                 ret = -EINVAL;
 710                 goto reject;
 711         }
 712         if (strstr(open_msg->dev_name, "..")) {
 713                 pr_err("Opening device for session %s failed, device path %s contains relative path ..\n",
 714                        srv_sess->sessname, open_msg->dev_name);
 715                 ret = -EINVAL;
 716                 goto reject;
 717         }
 718         full_path = rnbd_srv_get_full_path(srv_sess, open_msg->dev_name);
 719         if (IS_ERR(full_path)) {
 720                 ret = PTR_ERR(full_path);
 721                 pr_err("Opening device '%s' for client %s failed, failed to get device full path, err: %pe\n",
 722                        open_msg->dev_name, srv_sess->sessname, full_path);
 723                 goto reject;
 724         }
 725
 726         bdev_file = bdev_file_open_by_path(full_path, open_flags, NULL, NULL);
 727         if (IS_ERR(bdev_file)) {
 728                 ret = PTR_ERR(bdev_file);
 729                 pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %pe\n",
 730                        full_path, srv_sess->sessname, bdev_file);
 731                 goto free_path;
 732         }
 733
 734         srv_dev = rnbd_srv_get_or_create_srv_dev(file_bdev(bdev_file), srv_sess,
 735                                                   open_msg->access_mode);
 736         if (IS_ERR(srv_dev)) {
 737                 pr_err("Opening device '%s' on session %s failed, creating srv_dev failed, err: %pe\n",
 738                        full_path, srv_sess->sessname, srv_dev);
 739                 ret = PTR_ERR(srv_dev);
 740                 goto blkdev_put;
 741         }
 742
 743         srv_sess_dev = rnbd_srv_create_set_sess_dev(srv_sess, open_msg,
 744                                 bdev_file,
 745                                 open_msg->access_mode == RNBD_ACCESS_RO,
 746                                 srv_dev);
 747         if (IS_ERR(srv_sess_dev)) {
 748                 pr_err("Opening device '%s' on session %s failed, creating sess_dev failed, err: %pe\n",
 749                        full_path, srv_sess->sessname, srv_sess_dev);
 750                 ret = PTR_ERR(srv_sess_dev);
 751                 goto srv_dev_put;
 752         }
 753
 754         /* Create the srv_dev sysfs files if they haven't been created yet. The
 755          * reason to delay the creation is not to create the sysfs files before
 756          * we are sure the device can be opened.
 757          */
 758         mutex_lock(&srv_dev->lock);
 759         if (!srv_dev->dev_kobj.state_in_sysfs) {
 760                 ret = rnbd_srv_create_dev_sysfs(srv_dev, file_bdev(bdev_file));
 761                 if (ret) {
 762                         mutex_unlock(&srv_dev->lock);
 763                         rnbd_srv_err(srv_sess_dev,
 764                                       "Opening device failed, failed to create device sysfs files, err: %d\n",
 765                                       ret);
 766                         goto free_srv_sess_dev;
 767                 }
 768         }
 769
 770         ret = rnbd_srv_create_dev_session_sysfs(srv_sess_dev);
 771         if (ret) {
 772                 mutex_unlock(&srv_dev->lock);
 773                 rnbd_srv_err(srv_sess_dev,
 774                               "Opening device failed, failed to create dev client sysfs files, err: %d\n",
 775                               ret);
 776                 goto free_srv_sess_dev;
 777         }
 778
 779         list_add(&srv_sess_dev->dev_list, &srv_dev->sess_dev_list);
 780         mutex_unlock(&srv_dev->lock);
 781
 782         rnbd_srv_info(srv_sess_dev, "Opened device '%s'\n", srv_dev->name);
 783
 784         kfree(full_path);
 785
 786 fill_response:
 787         rnbd_srv_fill_msg_open_rsp(rsp, srv_sess_dev);
 788         mutex_unlock(&srv_sess->lock);
 789         return 0;
 790
 791 free_srv_sess_dev:
 792         xa_erase(&srv_sess->index_idr, srv_sess_dev->device_id);
 793         synchronize_rcu();
 794         kfree(srv_sess_dev);
 795 srv_dev_put:
 796         if (open_msg->access_mode != RNBD_ACCESS_RO) {
 797                 mutex_lock(&srv_dev->lock);
 798                 srv_dev->open_write_cnt--;
 799                 mutex_unlock(&srv_dev->lock);
 800         }
 801         rnbd_put_srv_dev(srv_dev);
 802 blkdev_put:
 803         fput(bdev_file);
 804 free_path:
 805         kfree(full_path);
 806 reject:
 807         mutex_unlock(&srv_sess->lock);
 808         return ret;
 809 }
 810
 811 static struct rtrs_srv_ctx *rtrs_ctx;
 812
 813 static struct rtrs_srv_ops rtrs_ops;
 814 static int __init rnbd_srv_init_module(void)
 815 {
 816         int err = 0;
 817
 818         BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
 819         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
 820         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
 821         BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
 822         BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
 823         BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
 824         rtrs_ops = (struct rtrs_srv_ops) {
 825                 .rdma_ev = rnbd_srv_rdma_ev,
 826                 .link_ev = rnbd_srv_link_ev,
 827         };
 828         rtrs_ctx = rtrs_srv_open(&rtrs_ops, port_nr);
 829         if (IS_ERR(rtrs_ctx)) {
 830                 pr_err("rtrs_srv_open(), err: %pe\n", rtrs_ctx);
 831                 return PTR_ERR(rtrs_ctx);
 832         }
 833
 834         err = rnbd_srv_create_sysfs_files();
 835         if (err) {
 836                 pr_err("rnbd_srv_create_sysfs_files(), err: %d\n", err);
 837                 rtrs_srv_close(rtrs_ctx);
 838         }
 839
 840         return err;
 841 }
 842
 843 static void __exit rnbd_srv_cleanup_module(void)
 844 {
 845         rtrs_srv_close(rtrs_ctx);
 846         WARN_ON(!list_empty(&sess_list));
 847         rnbd_srv_destroy_sysfs_files();
 848 }
 849
 850 module_init(rnbd_srv_init_module);
 851 module_exit(rnbd_srv_cleanup_module);