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-dev.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 void rnbd_endio(void *priv, int error)
  88 {
  89         struct rnbd_io_private *rnbd_priv = priv;
  90         struct rnbd_srv_sess_dev *sess_dev = rnbd_priv->sess_dev;
  91
  92         rnbd_put_sess_dev(sess_dev);
  93
  94         rtrs_srv_resp_rdma(rnbd_priv->id, error);
  95
  96         kfree(priv);
  97 }
  98
  99 static struct rnbd_srv_sess_dev *
 100 rnbd_get_sess_dev(int dev_id, struct rnbd_srv_session *srv_sess)
 101 {
 102         struct rnbd_srv_sess_dev *sess_dev;
 103         int ret = 0;
 104
 105         rcu_read_lock();
 106         sess_dev = xa_load(&srv_sess->index_idr, dev_id);
 107         if (likely(sess_dev))
 108                 ret = kref_get_unless_zero(&sess_dev->kref);
 109         rcu_read_unlock();
 110
 111         if (!sess_dev || !ret)
 112                 return ERR_PTR(-ENXIO);
 113
 114         return sess_dev;
 115 }
 116
 117 static int process_rdma(struct rtrs_srv *sess,
 118                         struct rnbd_srv_session *srv_sess,
 119                         struct rtrs_srv_op *id, void *data, u32 datalen,
 120                         const void *usr, size_t usrlen)
 121 {
 122         const struct rnbd_msg_io *msg = usr;
 123         struct rnbd_io_private *priv;
 124         struct rnbd_srv_sess_dev *sess_dev;
 125         u32 dev_id;
 126         int err;
 127         struct rnbd_dev_blk_io *io;
 128         struct bio *bio;
 129         short prio;
 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\n",
 140                                    srv_sess->sessname, dev_id);
 141                 err = -ENOTCONN;
 142                 goto err;
 143         }
 144
 145         priv->sess_dev = sess_dev;
 146         priv->id = id;
 147
 148         /* Generate bio with pages pointing to the rdma buffer */
 149         bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
 150         if (IS_ERR(bio)) {
 151                 err = PTR_ERR(bio);
 152                 rnbd_srv_err(sess_dev, "Failed to generate bio, err: %d\n", err);
 153                 goto sess_dev_put;
 154         }
 155
 156         io = container_of(bio, struct rnbd_dev_blk_io, bio);
 157         io->dev = sess_dev->rnbd_dev;
 158         io->priv = priv;
 159
 160         bio->bi_end_io = rnbd_dev_bi_end_io;
 161         bio->bi_private = io;
 162         bio->bi_opf = rnbd_to_bio_flags(le32_to_cpu(msg->rw));
 163         bio->bi_iter.bi_sector = le64_to_cpu(msg->sector);
 164         bio->bi_iter.bi_size = le32_to_cpu(msg->bi_size);
 165         prio = srv_sess->ver < RNBD_PROTO_VER_MAJOR ||
 166                usrlen < sizeof(*msg) ? 0 : le16_to_cpu(msg->prio);
 167         bio_set_prio(bio, prio);
 168         bio_set_dev(bio, sess_dev->rnbd_dev->bdev);
 169
 170         submit_bio(bio);
 171
 172         return 0;
 173
 174 sess_dev_put:
 175         rnbd_put_sess_dev(sess_dev);
 176 err:
 177         kfree(priv);
 178         return err;
 179 }
 180
 181 static void destroy_device(struct rnbd_srv_dev *dev)
 182 {
 183         WARN_ONCE(!list_empty(&dev->sess_dev_list),
 184                   "Device %s is being destroyed but still in use!\n",
 185                   dev->id);
 186
 187         spin_lock(&dev_lock);
 188         list_del(&dev->list);
 189         spin_unlock(&dev_lock);
 190
 191         mutex_destroy(&dev->lock);
 192         if (dev->dev_kobj.state_in_sysfs)
 193                 /*
 194                  * Destroy kobj only if it was really created.
 195                  */
 196                 rnbd_srv_destroy_dev_sysfs(dev);
 197         else
 198                 kfree(dev);
 199 }
 200
 201 static void destroy_device_cb(struct kref *kref)
 202 {
 203         struct rnbd_srv_dev *dev;
 204
 205         dev = container_of(kref, struct rnbd_srv_dev, kref);
 206
 207         destroy_device(dev);
 208 }
 209
 210 static void rnbd_put_srv_dev(struct rnbd_srv_dev *dev)
 211 {
 212         kref_put(&dev->kref, destroy_device_cb);
 213 }
 214
 215 void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev)
 216 {
 217         DECLARE_COMPLETION_ONSTACK(dc);
 218
 219         xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
 220         synchronize_rcu();
 221         sess_dev->destroy_comp = &dc;
 222         rnbd_put_sess_dev(sess_dev);
 223         wait_for_completion(&dc); /* wait for inflights to drop to zero */
 224
 225         rnbd_dev_close(sess_dev->rnbd_dev);
 226         list_del(&sess_dev->sess_list);
 227         mutex_lock(&sess_dev->dev->lock);
 228         list_del(&sess_dev->dev_list);
 229         if (sess_dev->open_flags & FMODE_WRITE)
 230                 sess_dev->dev->open_write_cnt--;
 231         mutex_unlock(&sess_dev->dev->lock);
 232
 233         rnbd_put_srv_dev(sess_dev->dev);
 234
 235         rnbd_srv_info(sess_dev, "Device closed\n");
 236         kfree(sess_dev);
 237 }
 238
 239 static void destroy_sess(struct rnbd_srv_session *srv_sess)
 240 {
 241         struct rnbd_srv_sess_dev *sess_dev, *tmp;
 242
 243         if (list_empty(&srv_sess->sess_dev_list))
 244                 goto out;
 245
 246         mutex_lock(&srv_sess->lock);
 247         list_for_each_entry_safe(sess_dev, tmp, &srv_sess->sess_dev_list,
 248                                  sess_list)
 249                 rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 250         mutex_unlock(&srv_sess->lock);
 251
 252 out:
 253         xa_destroy(&srv_sess->index_idr);
 254         bioset_exit(&srv_sess->sess_bio_set);
 255
 256         pr_info("RTRS Session %s disconnected\n", srv_sess->sessname);
 257
 258         mutex_lock(&sess_lock);
 259         list_del(&srv_sess->list);
 260         mutex_unlock(&sess_lock);
 261
 262         mutex_destroy(&srv_sess->lock);
 263         kfree(srv_sess);
 264 }
 265
 266 static int create_sess(struct rtrs_srv *rtrs)
 267 {
 268         struct rnbd_srv_session *srv_sess;
 269         char sessname[NAME_MAX];
 270         int err;
 271
 272         err = rtrs_srv_get_sess_name(rtrs, sessname, sizeof(sessname));
 273         if (err) {
 274                 pr_err("rtrs_srv_get_sess_name(%s): %d\n", sessname, err);
 275
 276                 return err;
 277         }
 278         srv_sess = kzalloc(sizeof(*srv_sess), GFP_KERNEL);
 279         if (!srv_sess)
 280                 return -ENOMEM;
 281
 282         srv_sess->queue_depth = rtrs_srv_get_queue_depth(rtrs);
 283         err = bioset_init(&srv_sess->sess_bio_set, srv_sess->queue_depth,
 284                           offsetof(struct rnbd_dev_blk_io, bio),
 285                           BIOSET_NEED_BVECS);
 286         if (err) {
 287                 pr_err("Allocating srv_session for session %s failed\n",
 288                        sessname);
 289                 kfree(srv_sess);
 290                 return err;
 291         }
 292
 293         xa_init_flags(&srv_sess->index_idr, XA_FLAGS_ALLOC);
 294         INIT_LIST_HEAD(&srv_sess->sess_dev_list);
 295         mutex_init(&srv_sess->lock);
 296         mutex_lock(&sess_lock);
 297         list_add(&srv_sess->list, &sess_list);
 298         mutex_unlock(&sess_lock);
 299
 300         srv_sess->rtrs = rtrs;
 301         strlcpy(srv_sess->sessname, sessname, sizeof(srv_sess->sessname));
 302
 303         rtrs_srv_set_sess_priv(rtrs, srv_sess);
 304
 305         return 0;
 306 }
 307
 308 static int rnbd_srv_link_ev(struct rtrs_srv *rtrs,
 309                              enum rtrs_srv_link_ev ev, void *priv)
 310 {
 311         struct rnbd_srv_session *srv_sess = priv;
 312
 313         switch (ev) {
 314         case RTRS_SRV_LINK_EV_CONNECTED:
 315                 return create_sess(rtrs);
 316
 317         case RTRS_SRV_LINK_EV_DISCONNECTED:
 318                 if (WARN_ON_ONCE(!srv_sess))
 319                         return -EINVAL;
 320
 321                 destroy_sess(srv_sess);
 322                 return 0;
 323
 324         default:
 325                 pr_warn("Received unknown RTRS session event %d from session %s\n",
 326                         ev, srv_sess->sessname);
 327                 return -EINVAL;
 328         }
 329 }
 330
 331 static int process_msg_close(struct rtrs_srv *rtrs,
 332                              struct rnbd_srv_session *srv_sess,
 333                              void *data, size_t datalen, const void *usr,
 334                              size_t usrlen)
 335 {
 336         const struct rnbd_msg_close *close_msg = usr;
 337         struct rnbd_srv_sess_dev *sess_dev;
 338
 339         sess_dev = rnbd_get_sess_dev(le32_to_cpu(close_msg->device_id),
 340                                       srv_sess);
 341         if (IS_ERR(sess_dev))
 342                 return 0;
 343
 344         rnbd_put_sess_dev(sess_dev);
 345         mutex_lock(&srv_sess->lock);
 346         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 347         mutex_unlock(&srv_sess->lock);
 348         return 0;
 349 }
 350
 351 static int process_msg_open(struct rtrs_srv *rtrs,
 352                             struct rnbd_srv_session *srv_sess,
 353                             const void *msg, size_t len,
 354                             void *data, size_t datalen);
 355
 356 static int process_msg_sess_info(struct rtrs_srv *rtrs,
 357                                  struct rnbd_srv_session *srv_sess,
 358                                  const void *msg, size_t len,
 359                                  void *data, size_t datalen);
 360
 361 static int rnbd_srv_rdma_ev(struct rtrs_srv *rtrs, void *priv,
 362                              struct rtrs_srv_op *id, int dir,
 363                              void *data, size_t datalen, const void *usr,
 364                              size_t usrlen)
 365 {
 366         struct rnbd_srv_session *srv_sess = priv;
 367         const struct rnbd_msg_hdr *hdr = usr;
 368         int ret = 0;
 369         u16 type;
 370
 371         if (WARN_ON_ONCE(!srv_sess))
 372                 return -ENODEV;
 373
 374         type = le16_to_cpu(hdr->type);
 375
 376         switch (type) {
 377         case RNBD_MSG_IO:
 378                 return process_rdma(rtrs, srv_sess, id, data, datalen, usr,
 379                                     usrlen);
 380         case RNBD_MSG_CLOSE:
 381                 ret = process_msg_close(rtrs, srv_sess, data, datalen,
 382                                         usr, usrlen);
 383                 break;
 384         case RNBD_MSG_OPEN:
 385                 ret = process_msg_open(rtrs, srv_sess, usr, usrlen,
 386                                        data, datalen);
 387                 break;
 388         case RNBD_MSG_SESS_INFO:
 389                 ret = process_msg_sess_info(rtrs, srv_sess, usr, usrlen,
 390                                             data, datalen);
 391                 break;
 392         default:
 393                 pr_warn("Received unexpected message type %d with dir %d from session %s\n",
 394                         type, dir, srv_sess->sessname);
 395                 return -EINVAL;
 396         }
 397
 398         rtrs_srv_resp_rdma(id, ret);
 399         return 0;
 400 }
 401
 402 static struct rnbd_srv_sess_dev
 403 *rnbd_sess_dev_alloc(struct rnbd_srv_session *srv_sess)
 404 {
 405         struct rnbd_srv_sess_dev *sess_dev;
 406         int error;
 407
 408         sess_dev = kzalloc(sizeof(*sess_dev), GFP_KERNEL);
 409         if (!sess_dev)
 410                 return ERR_PTR(-ENOMEM);
 411
 412         error = xa_alloc(&srv_sess->index_idr, &sess_dev->device_id, sess_dev,
 413                          xa_limit_32b, GFP_NOWAIT);
 414         if (error < 0) {
 415                 pr_warn("Allocating idr failed, err: %d\n", error);
 416                 kfree(sess_dev);
 417                 return ERR_PTR(error);
 418         }
 419
 420         return sess_dev;
 421 }
 422
 423 static struct rnbd_srv_dev *rnbd_srv_init_srv_dev(const char *id)
 424 {
 425         struct rnbd_srv_dev *dev;
 426
 427         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 428         if (!dev)
 429                 return ERR_PTR(-ENOMEM);
 430
 431         strlcpy(dev->id, id, sizeof(dev->id));
 432         kref_init(&dev->kref);
 433         INIT_LIST_HEAD(&dev->sess_dev_list);
 434         mutex_init(&dev->lock);
 435
 436         return dev;
 437 }
 438
 439 static struct rnbd_srv_dev *
 440 rnbd_srv_find_or_add_srv_dev(struct rnbd_srv_dev *new_dev)
 441 {
 442         struct rnbd_srv_dev *dev;
 443
 444         spin_lock(&dev_lock);
 445         list_for_each_entry(dev, &dev_list, list) {
 446                 if (!strncmp(dev->id, new_dev->id, sizeof(dev->id))) {
 447                         if (!kref_get_unless_zero(&dev->kref))
 448                                 /*
 449                                  * We lost the race, device is almost dead.
 450                                  *  Continue traversing to find a valid one.
 451                                  */
 452                                 continue;
 453                         spin_unlock(&dev_lock);
 454                         return dev;
 455                 }
 456         }
 457         list_add(&new_dev->list, &dev_list);
 458         spin_unlock(&dev_lock);
 459
 460         return new_dev;
 461 }
 462
 463 static int rnbd_srv_check_update_open_perm(struct rnbd_srv_dev *srv_dev,
 464                                             struct rnbd_srv_session *srv_sess,
 465                                             enum rnbd_access_mode access_mode)
 466 {
 467         int ret = -EPERM;
 468
 469         mutex_lock(&srv_dev->lock);
 470
 471         switch (access_mode) {
 472         case RNBD_ACCESS_RO:
 473                 ret = 0;
 474                 break;
 475         case RNBD_ACCESS_RW:
 476                 if (srv_dev->open_write_cnt == 0)  {
 477                         srv_dev->open_write_cnt++;
 478                         ret = 0;
 479                 } else {
 480                         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",
 481                                srv_dev->id, srv_sess->sessname,
 482                                srv_dev->open_write_cnt,
 483                                rnbd_access_mode_str(access_mode));
 484                 }
 485                 break;
 486         case RNBD_ACCESS_MIGRATION:
 487                 if (srv_dev->open_write_cnt < 2) {
 488                         srv_dev->open_write_cnt++;
 489                         ret = 0;
 490                 } else {
 491                         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",
 492                                srv_dev->id, srv_sess->sessname,
 493                                srv_dev->open_write_cnt,
 494                                rnbd_access_mode_str(access_mode));
 495                 }
 496                 break;
 497         default:
 498                 pr_err("Received mapping request for device '%s' on session %s with invalid access mode: %d\n",
 499                        srv_dev->id, srv_sess->sessname, access_mode);
 500                 ret = -EINVAL;
 501         }
 502
 503         mutex_unlock(&srv_dev->lock);
 504
 505         return ret;
 506 }
 507
 508 static struct rnbd_srv_dev *
 509 rnbd_srv_get_or_create_srv_dev(struct rnbd_dev *rnbd_dev,
 510                                 struct rnbd_srv_session *srv_sess,
 511                                 enum rnbd_access_mode access_mode)
 512 {
 513         int ret;
 514         struct rnbd_srv_dev *new_dev, *dev;
 515
 516         new_dev = rnbd_srv_init_srv_dev(rnbd_dev->name);
 517         if (IS_ERR(new_dev))
 518                 return new_dev;
 519
 520         dev = rnbd_srv_find_or_add_srv_dev(new_dev);
 521         if (dev != new_dev)
 522                 kfree(new_dev);
 523
 524         ret = rnbd_srv_check_update_open_perm(dev, srv_sess, access_mode);
 525         if (ret) {
 526                 rnbd_put_srv_dev(dev);
 527                 return ERR_PTR(ret);
 528         }
 529
 530         return dev;
 531 }
 532
 533 static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
 534                                         struct rnbd_srv_sess_dev *sess_dev)
 535 {
 536         struct rnbd_dev *rnbd_dev = sess_dev->rnbd_dev;
 537
 538         rsp->hdr.type = cpu_to_le16(RNBD_MSG_OPEN_RSP);
 539         rsp->device_id =
 540                 cpu_to_le32(sess_dev->device_id);
 541         rsp->nsectors =
 542                 cpu_to_le64(get_capacity(rnbd_dev->bdev->bd_disk));
 543         rsp->logical_block_size =
 544                 cpu_to_le16(bdev_logical_block_size(rnbd_dev->bdev));
 545         rsp->physical_block_size =
 546                 cpu_to_le16(bdev_physical_block_size(rnbd_dev->bdev));
 547         rsp->max_segments =
 548                 cpu_to_le16(rnbd_dev_get_max_segs(rnbd_dev));
 549         rsp->max_hw_sectors =
 550                 cpu_to_le32(rnbd_dev_get_max_hw_sects(rnbd_dev));
 551         rsp->max_write_same_sectors =
 552                 cpu_to_le32(bdev_write_same(rnbd_dev->bdev));
 553         rsp->max_discard_sectors =
 554                 cpu_to_le32(rnbd_dev_get_max_discard_sects(rnbd_dev));
 555         rsp->discard_granularity =
 556                 cpu_to_le32(rnbd_dev_get_discard_granularity(rnbd_dev));
 557         rsp->discard_alignment =
 558                 cpu_to_le32(rnbd_dev_get_discard_alignment(rnbd_dev));
 559         rsp->secure_discard =
 560                 cpu_to_le16(rnbd_dev_get_secure_discard(rnbd_dev));
 561         rsp->rotational =
 562                 !blk_queue_nonrot(bdev_get_queue(rnbd_dev->bdev));
 563 }
 564
 565 static struct rnbd_srv_sess_dev *
 566 rnbd_srv_create_set_sess_dev(struct rnbd_srv_session *srv_sess,
 567                               const struct rnbd_msg_open *open_msg,
 568                               struct rnbd_dev *rnbd_dev, fmode_t open_flags,
 569                               struct rnbd_srv_dev *srv_dev)
 570 {
 571         struct rnbd_srv_sess_dev *sdev = rnbd_sess_dev_alloc(srv_sess);
 572
 573         if (IS_ERR(sdev))
 574                 return sdev;
 575
 576         kref_init(&sdev->kref);
 577
 578         strlcpy(sdev->pathname, open_msg->dev_name, sizeof(sdev->pathname));
 579
 580         sdev->rnbd_dev          = rnbd_dev;
 581         sdev->sess              = srv_sess;
 582         sdev->dev               = srv_dev;
 583         sdev->open_flags        = open_flags;
 584         sdev->access_mode       = open_msg->access_mode;
 585
 586         return sdev;
 587 }
 588
 589 static char *rnbd_srv_get_full_path(struct rnbd_srv_session *srv_sess,
 590                                      const char *dev_name)
 591 {
 592         char *full_path;
 593         char *a, *b;
 594
 595         full_path = kmalloc(PATH_MAX, GFP_KERNEL);
 596         if (!full_path)
 597                 return ERR_PTR(-ENOMEM);
 598
 599         /*
 600          * Replace %SESSNAME% with a real session name in order to
 601          * create device namespace.
 602          */
 603         a = strnstr(dev_search_path, "%SESSNAME%", sizeof(dev_search_path));
 604         if (a) {
 605                 int len = a - dev_search_path;
 606
 607                 len = snprintf(full_path, PATH_MAX, "%.*s/%s/%s", len,
 608                                dev_search_path, srv_sess->sessname, dev_name);
 609                 if (len >= PATH_MAX) {
 610                         pr_err("Too long path: %s, %s, %s\n",
 611                                dev_search_path, srv_sess->sessname, dev_name);
 612                         kfree(full_path);
 613                         return ERR_PTR(-EINVAL);
 614                 }
 615         } else {
 616                 snprintf(full_path, PATH_MAX, "%s/%s",
 617                          dev_search_path, dev_name);
 618         }
 619
 620         /* eliminitate duplicated slashes */
 621         a = strchr(full_path, '/');
 622         b = a;
 623         while (*b != '\0') {
 624                 if (*b == '/' && *a == '/') {
 625                         b++;
 626                 } else {
 627                         a++;
 628                         *a = *b;
 629                         b++;
 630                 }
 631         }
 632         a++;
 633         *a = '\0';
 634
 635         return full_path;
 636 }
 637
 638 static int process_msg_sess_info(struct rtrs_srv *rtrs,
 639                                  struct rnbd_srv_session *srv_sess,
 640                                  const void *msg, size_t len,
 641                                  void *data, size_t datalen)
 642 {
 643         const struct rnbd_msg_sess_info *sess_info_msg = msg;
 644         struct rnbd_msg_sess_info_rsp *rsp = data;
 645
 646         srv_sess->ver = min_t(u8, sess_info_msg->ver, RNBD_PROTO_VER_MAJOR);
 647         pr_debug("Session %s using protocol version %d (client version: %d, server version: %d)\n",
 648                  srv_sess->sessname, srv_sess->ver,
 649                  sess_info_msg->ver, RNBD_PROTO_VER_MAJOR);
 650
 651         rsp->hdr.type = cpu_to_le16(RNBD_MSG_SESS_INFO_RSP);
 652         rsp->ver = srv_sess->ver;
 653
 654         return 0;
 655 }
 656
 657 /**
 658  * find_srv_sess_dev() - a dev is already opened by this name
 659  * @srv_sess:   the session to search.
 660  * @dev_name:   string containing the name of the device.
 661  *
 662  * Return struct rnbd_srv_sess_dev if srv_sess already opened the dev_name
 663  * NULL if the session didn't open the device yet.
 664  */
 665 static struct rnbd_srv_sess_dev *
 666 find_srv_sess_dev(struct rnbd_srv_session *srv_sess, const char *dev_name)
 667 {
 668         struct rnbd_srv_sess_dev *sess_dev;
 669
 670         if (list_empty(&srv_sess->sess_dev_list))
 671                 return NULL;
 672
 673         list_for_each_entry(sess_dev, &srv_sess->sess_dev_list, sess_list)
 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 rtrs_srv *rtrs,
 681                             struct rnbd_srv_session *srv_sess,
 682                             const void *msg, size_t len,
 683                             void *data, size_t datalen)
 684 {
 685         int ret;
 686         struct rnbd_srv_dev *srv_dev;
 687         struct rnbd_srv_sess_dev *srv_sess_dev;
 688         const struct rnbd_msg_open *open_msg = msg;
 689         fmode_t open_flags;
 690         char *full_path;
 691         struct rnbd_dev *rnbd_dev;
 692         struct rnbd_msg_open_rsp *rsp = data;
 693
 694         pr_debug("Open message received: session='%s' path='%s' access_mode=%d\n",
 695                  srv_sess->sessname, open_msg->dev_name,
 696                  open_msg->access_mode);
 697         open_flags = FMODE_READ;
 698         if (open_msg->access_mode != RNBD_ACCESS_RO)
 699                 open_flags |= FMODE_WRITE;
 700
 701         mutex_lock(&srv_sess->lock);
 702
 703         srv_sess_dev = find_srv_sess_dev(srv_sess, open_msg->dev_name);
 704         if (srv_sess_dev)
 705                 goto fill_response;
 706
 707         if ((strlen(dev_search_path) + strlen(open_msg->dev_name))
 708             >= PATH_MAX) {
 709                 pr_err("Opening device for session %s failed, device path too long. '%s/%s' is longer than PATH_MAX (%d)\n",
 710                        srv_sess->sessname, dev_search_path, open_msg->dev_name,
 711                        PATH_MAX);
 712                 ret = -EINVAL;
 713                 goto reject;
 714         }
 715         if (strstr(open_msg->dev_name, "..")) {
 716                 pr_err("Opening device for session %s failed, device path %s contains relative path ..\n",
 717                        srv_sess->sessname, open_msg->dev_name);
 718                 ret = -EINVAL;
 719                 goto reject;
 720         }
 721         full_path = rnbd_srv_get_full_path(srv_sess, open_msg->dev_name);
 722         if (IS_ERR(full_path)) {
 723                 ret = PTR_ERR(full_path);
 724                 pr_err("Opening device '%s' for client %s failed, failed to get device full path, err: %d\n",
 725                        open_msg->dev_name, srv_sess->sessname, ret);
 726                 goto reject;
 727         }
 728
 729         rnbd_dev = rnbd_dev_open(full_path, open_flags,
 730                                  &srv_sess->sess_bio_set);
 731         if (IS_ERR(rnbd_dev)) {
 732                 pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %ld\n",
 733                        full_path, srv_sess->sessname, PTR_ERR(rnbd_dev));
 734                 ret = PTR_ERR(rnbd_dev);
 735                 goto free_path;
 736         }
 737
 738         srv_dev = rnbd_srv_get_or_create_srv_dev(rnbd_dev, srv_sess,
 739                                                   open_msg->access_mode);
 740         if (IS_ERR(srv_dev)) {
 741                 pr_err("Opening device '%s' on session %s failed, creating srv_dev failed, err: %ld\n",
 742                        full_path, srv_sess->sessname, PTR_ERR(srv_dev));
 743                 ret = PTR_ERR(srv_dev);
 744                 goto rnbd_dev_close;
 745         }
 746
 747         srv_sess_dev = rnbd_srv_create_set_sess_dev(srv_sess, open_msg,
 748                                                      rnbd_dev, open_flags,
 749                                                      srv_dev);
 750         if (IS_ERR(srv_sess_dev)) {
 751                 pr_err("Opening device '%s' on session %s failed, creating sess_dev failed, err: %ld\n",
 752                        full_path, srv_sess->sessname, PTR_ERR(srv_sess_dev));
 753                 ret = PTR_ERR(srv_sess_dev);
 754                 goto srv_dev_put;
 755         }
 756
 757         /* Create the srv_dev sysfs files if they haven't been created yet. The
 758          * reason to delay the creation is not to create the sysfs files before
 759          * we are sure the device can be opened.
 760          */
 761         mutex_lock(&srv_dev->lock);
 762         if (!srv_dev->dev_kobj.state_in_sysfs) {
 763                 ret = rnbd_srv_create_dev_sysfs(srv_dev, rnbd_dev->bdev,
 764                                                  rnbd_dev->name);
 765                 if (ret) {
 766                         mutex_unlock(&srv_dev->lock);
 767                         rnbd_srv_err(srv_sess_dev,
 768                                       "Opening device failed, failed to create device sysfs files, err: %d\n",
 769                                       ret);
 770                         goto free_srv_sess_dev;
 771                 }
 772         }
 773
 774         ret = rnbd_srv_create_dev_session_sysfs(srv_sess_dev);
 775         if (ret) {
 776                 mutex_unlock(&srv_dev->lock);
 777                 rnbd_srv_err(srv_sess_dev,
 778                               "Opening device failed, failed to create dev client sysfs files, err: %d\n",
 779                               ret);
 780                 goto free_srv_sess_dev;
 781         }
 782
 783         list_add(&srv_sess_dev->dev_list, &srv_dev->sess_dev_list);
 784         mutex_unlock(&srv_dev->lock);
 785
 786         list_add(&srv_sess_dev->sess_list, &srv_sess->sess_dev_list);
 787
 788         rnbd_srv_info(srv_sess_dev, "Opened device '%s'\n", srv_dev->id);
 789
 790         kfree(full_path);
 791
 792 fill_response:
 793         rnbd_srv_fill_msg_open_rsp(rsp, srv_sess_dev);
 794         mutex_unlock(&srv_sess->lock);
 795         return 0;
 796
 797 free_srv_sess_dev:
 798         xa_erase(&srv_sess->index_idr, srv_sess_dev->device_id);
 799         synchronize_rcu();
 800         kfree(srv_sess_dev);
 801 srv_dev_put:
 802         if (open_msg->access_mode != RNBD_ACCESS_RO) {
 803                 mutex_lock(&srv_dev->lock);
 804                 srv_dev->open_write_cnt--;
 805                 mutex_unlock(&srv_dev->lock);
 806         }
 807         rnbd_put_srv_dev(srv_dev);
 808 rnbd_dev_close:
 809         rnbd_dev_close(rnbd_dev);
 810 free_path:
 811         kfree(full_path);
 812 reject:
 813         mutex_unlock(&srv_sess->lock);
 814         return ret;
 815 }
 816
 817 static struct rtrs_srv_ctx *rtrs_ctx;
 818
 819 static struct rtrs_srv_ops rtrs_ops;
 820 static int __init rnbd_srv_init_module(void)
 821 {
 822         int err;
 823
 824         BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
 825         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
 826         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
 827         BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
 828         BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
 829         BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
 830         rtrs_ops = (struct rtrs_srv_ops) {
 831                 .rdma_ev = rnbd_srv_rdma_ev,
 832                 .link_ev = rnbd_srv_link_ev,
 833         };
 834         rtrs_ctx = rtrs_srv_open(&rtrs_ops, port_nr);
 835         if (IS_ERR(rtrs_ctx)) {
 836                 err = PTR_ERR(rtrs_ctx);
 837                 pr_err("rtrs_srv_open(), err: %d\n", err);
 838                 return err;
 839         }
 840
 841         err = rnbd_srv_create_sysfs_files();
 842         if (err) {
 843                 pr_err("rnbd_srv_create_sysfs_files(), err: %d\n", err);
 844                 rtrs_srv_close(rtrs_ctx);
 845                 return err;
 846         }
 847
 848         return 0;
 849 }
 850
 851 static void __exit rnbd_srv_cleanup_module(void)
 852 {
 853         rtrs_srv_close(rtrs_ctx);
 854         WARN_ON(!list_empty(&sess_list));
 855         rnbd_srv_destroy_sysfs_files();
 856 }
 857
 858 module_init(rnbd_srv_init_module);
 859 module_exit(rnbd_srv_cleanup_module);