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 (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 void rnbd_dev_bi_end_io(struct bio *bio)
 118 {
 119         rnbd_endio(bio->bi_private, blk_status_to_errno(bio->bi_status));
 120         bio_put(bio);
 121 }
 122
 123 static int process_rdma(struct rnbd_srv_session *srv_sess,
 124                         struct rtrs_srv_op *id, void *data, u32 datalen,
 125                         const void *usr, size_t usrlen)
 126 {
 127         const struct rnbd_msg_io *msg = usr;
 128         struct rnbd_io_private *priv;
 129         struct rnbd_srv_sess_dev *sess_dev;
 130         u32 dev_id;
 131         int err;
 132         struct bio *bio;
 133         short prio;
 134
 135         priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 136         if (!priv)
 137                 return -ENOMEM;
 138
 139         dev_id = le32_to_cpu(msg->device_id);
 140
 141         sess_dev = rnbd_get_sess_dev(dev_id, srv_sess);
 142         if (IS_ERR(sess_dev)) {
 143                 pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
 144                                    srv_sess->sessname, dev_id);
 145                 err = -ENOTCONN;
 146                 goto err;
 147         }
 148
 149         priv->sess_dev = sess_dev;
 150         priv->id = id;
 151
 152         bio = bio_alloc(sess_dev->rnbd_dev->bdev, 1,
 153                         rnbd_to_bio_flags(le32_to_cpu(msg->rw)), GFP_KERNEL);
 154         if (bio_add_page(bio, virt_to_page(data), datalen,
 155                         offset_in_page(data)) != datalen) {
 156                 rnbd_srv_err(sess_dev, "Failed to map data to bio\n");
 157                 err = -EINVAL;
 158                 goto bio_put;
 159         }
 160
 161         bio->bi_end_io = rnbd_dev_bi_end_io;
 162         bio->bi_private = priv;
 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
 169         submit_bio(bio);
 170
 171         return 0;
 172
 173 bio_put:
 174         bio_put(bio);
 175         rnbd_put_sess_dev(sess_dev);
 176 err:
 177         kfree(priv);
 178         return err;
 179 }
 180
 181 static void destroy_device(struct kref *kref)
 182 {
 183         struct rnbd_srv_dev *dev = container_of(kref, struct rnbd_srv_dev, kref);
 184
 185         WARN_ONCE(!list_empty(&dev->sess_dev_list),
 186                   "Device %s is being destroyed but still in use!\n",
 187                   dev->id);
 188
 189         spin_lock(&dev_lock);
 190         list_del(&dev->list);
 191         spin_unlock(&dev_lock);
 192
 193         mutex_destroy(&dev->lock);
 194         if (dev->dev_kobj.state_in_sysfs)
 195                 /*
 196                  * Destroy kobj only if it was really created.
 197                  */
 198                 rnbd_srv_destroy_dev_sysfs(dev);
 199         else
 200                 kfree(dev);
 201 }
 202
 203 static void rnbd_put_srv_dev(struct rnbd_srv_dev *dev)
 204 {
 205         kref_put(&dev->kref, destroy_device);
 206 }
 207
 208 void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id)
 209 {
 210         DECLARE_COMPLETION_ONSTACK(dc);
 211
 212         if (keep_id)
 213                 /* free the resources for the id but don't  */
 214                 /* allow to re-use the id itself because it */
 215                 /* is still used by the client              */
 216                 xa_cmpxchg(&sess_dev->sess->index_idr, sess_dev->device_id,
 217                            sess_dev, NULL, 0);
 218         else
 219                 xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
 220         synchronize_rcu();
 221
 222         sess_dev->destroy_comp = &dc;
 223         rnbd_put_sess_dev(sess_dev);
 224         wait_for_completion(&dc); /* wait for inflights to drop to zero */
 225
 226         rnbd_dev_close(sess_dev->rnbd_dev);
 227         list_del(&sess_dev->sess_list);
 228         mutex_lock(&sess_dev->dev->lock);
 229         list_del(&sess_dev->dev_list);
 230         if (sess_dev->open_flags & FMODE_WRITE)
 231                 sess_dev->dev->open_write_cnt--;
 232         mutex_unlock(&sess_dev->dev->lock);
 233
 234         rnbd_put_srv_dev(sess_dev->dev);
 235
 236         rnbd_srv_info(sess_dev, "Device closed\n");
 237         kfree(sess_dev);
 238 }
 239
 240 static void destroy_sess(struct rnbd_srv_session *srv_sess)
 241 {
 242         struct rnbd_srv_sess_dev *sess_dev, *tmp;
 243
 244         if (list_empty(&srv_sess->sess_dev_list))
 245                 goto out;
 246
 247         mutex_lock(&srv_sess->lock);
 248         list_for_each_entry_safe(sess_dev, tmp, &srv_sess->sess_dev_list,
 249                                  sess_list)
 250                 rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 251         mutex_unlock(&srv_sess->lock);
 252
 253 out:
 254         xa_destroy(&srv_sess->index_idr);
 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_sess *rtrs)
 267 {
 268         struct rnbd_srv_session *srv_sess;
 269         char pathname[NAME_MAX];
 270         int err;
 271
 272         err = rtrs_srv_get_path_name(rtrs, pathname, sizeof(pathname));
 273         if (err) {
 274                 pr_err("rtrs_srv_get_path_name(%s): %d\n", pathname, 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         xa_init_flags(&srv_sess->index_idr, XA_FLAGS_ALLOC);
 284         INIT_LIST_HEAD(&srv_sess->sess_dev_list);
 285         mutex_init(&srv_sess->lock);
 286         mutex_lock(&sess_lock);
 287         list_add(&srv_sess->list, &sess_list);
 288         mutex_unlock(&sess_lock);
 289
 290         srv_sess->rtrs = rtrs;
 291         strscpy(srv_sess->sessname, pathname, sizeof(srv_sess->sessname));
 292
 293         rtrs_srv_set_sess_priv(rtrs, srv_sess);
 294
 295         return 0;
 296 }
 297
 298 static int rnbd_srv_link_ev(struct rtrs_srv_sess *rtrs,
 299                              enum rtrs_srv_link_ev ev, void *priv)
 300 {
 301         struct rnbd_srv_session *srv_sess = priv;
 302
 303         switch (ev) {
 304         case RTRS_SRV_LINK_EV_CONNECTED:
 305                 return create_sess(rtrs);
 306
 307         case RTRS_SRV_LINK_EV_DISCONNECTED:
 308                 if (WARN_ON_ONCE(!srv_sess))
 309                         return -EINVAL;
 310
 311                 destroy_sess(srv_sess);
 312                 return 0;
 313
 314         default:
 315                 pr_warn("Received unknown RTRS session event %d from session %s\n",
 316                         ev, srv_sess->sessname);
 317                 return -EINVAL;
 318         }
 319 }
 320
 321 void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
 322                                    struct kobj_attribute *attr)
 323 {
 324         struct rnbd_srv_session *sess = sess_dev->sess;
 325
 326         sess_dev->keep_id = true;
 327         /* It is already started to close by client's close message. */
 328         if (!mutex_trylock(&sess->lock))
 329                 return;
 330         /* first remove sysfs itself to avoid deadlock */
 331         sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
 332         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 333         mutex_unlock(&sess->lock);
 334 }
 335
 336 static int process_msg_close(struct rnbd_srv_session *srv_sess,
 337                              void *data, size_t datalen, const void *usr,
 338                              size_t usrlen)
 339 {
 340         const struct rnbd_msg_close *close_msg = usr;
 341         struct rnbd_srv_sess_dev *sess_dev;
 342
 343         sess_dev = rnbd_get_sess_dev(le32_to_cpu(close_msg->device_id),
 344                                       srv_sess);
 345         if (IS_ERR(sess_dev))
 346                 return 0;
 347
 348         rnbd_put_sess_dev(sess_dev);
 349         mutex_lock(&srv_sess->lock);
 350         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 351         mutex_unlock(&srv_sess->lock);
 352         return 0;
 353 }
 354
 355 static int process_msg_open(struct rnbd_srv_session *srv_sess,
 356                             const void *msg, size_t len,
 357                             void *data, size_t datalen);
 358
 359 static int process_msg_sess_info(struct rnbd_srv_session *srv_sess,
 360                                  const void *msg, size_t len,
 361                                  void *data, size_t datalen);
 362
 363 static int rnbd_srv_rdma_ev(void *priv,
 364                             struct rtrs_srv_op *id, int dir,
 365                             void *data, size_t datalen, const void *usr,
 366                             size_t usrlen)
 367 {
 368         struct rnbd_srv_session *srv_sess = priv;
 369         const struct rnbd_msg_hdr *hdr = usr;
 370         int ret = 0;
 371         u16 type;
 372
 373         if (WARN_ON_ONCE(!srv_sess))
 374                 return -ENODEV;
 375
 376         type = le16_to_cpu(hdr->type);
 377
 378         switch (type) {
 379         case RNBD_MSG_IO:
 380                 return process_rdma(srv_sess, id, data, datalen, usr, usrlen);
 381         case RNBD_MSG_CLOSE:
 382                 ret = process_msg_close(srv_sess, data, datalen, usr, usrlen);
 383                 break;
 384         case RNBD_MSG_OPEN:
 385                 ret = process_msg_open(srv_sess, usr, usrlen, data, datalen);
 386                 break;
 387         case RNBD_MSG_SESS_INFO:
 388                 ret = process_msg_sess_info(srv_sess, usr, usrlen, data,
 389                                             datalen);
 390                 break;
 391         default:
 392                 pr_warn("Received unexpected message type %d with dir %d from session %s\n",
 393                         type, dir, srv_sess->sessname);
 394                 return -EINVAL;
 395         }
 396
 397         rtrs_srv_resp_rdma(id, ret);
 398         return 0;
 399 }
 400
 401 static struct rnbd_srv_sess_dev
 402 *rnbd_sess_dev_alloc(struct rnbd_srv_session *srv_sess)
 403 {
 404         struct rnbd_srv_sess_dev *sess_dev;
 405         int error;
 406
 407         sess_dev = kzalloc(sizeof(*sess_dev), GFP_KERNEL);
 408         if (!sess_dev)
 409                 return ERR_PTR(-ENOMEM);
 410
 411         error = xa_alloc(&srv_sess->index_idr, &sess_dev->device_id, sess_dev,
 412                          xa_limit_32b, GFP_NOWAIT);
 413         if (error < 0) {
 414                 pr_warn("Allocating idr failed, err: %d\n", error);
 415                 kfree(sess_dev);
 416                 return ERR_PTR(error);
 417         }
 418
 419         return sess_dev;
 420 }
 421
 422 static struct rnbd_srv_dev *rnbd_srv_init_srv_dev(const char *id)
 423 {
 424         struct rnbd_srv_dev *dev;
 425
 426         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 427         if (!dev)
 428                 return ERR_PTR(-ENOMEM);
 429
 430         strscpy(dev->id, id, sizeof(dev->id));
 431         kref_init(&dev->kref);
 432         INIT_LIST_HEAD(&dev->sess_dev_list);
 433         mutex_init(&dev->lock);
 434
 435         return dev;
 436 }
 437
 438 static struct rnbd_srv_dev *
 439 rnbd_srv_find_or_add_srv_dev(struct rnbd_srv_dev *new_dev)
 440 {
 441         struct rnbd_srv_dev *dev;
 442
 443         spin_lock(&dev_lock);
 444         list_for_each_entry(dev, &dev_list, list) {
 445                 if (!strncmp(dev->id, new_dev->id, sizeof(dev->id))) {
 446                         if (!kref_get_unless_zero(&dev->kref))
 447                                 /*
 448                                  * We lost the race, device is almost dead.
 449                                  *  Continue traversing to find a valid one.
 450                                  */
 451                                 continue;
 452                         spin_unlock(&dev_lock);
 453                         return dev;
 454                 }
 455         }
 456         list_add(&new_dev->list, &dev_list);
 457         spin_unlock(&dev_lock);
 458
 459         return new_dev;
 460 }
 461
 462 static int rnbd_srv_check_update_open_perm(struct rnbd_srv_dev *srv_dev,
 463                                             struct rnbd_srv_session *srv_sess,
 464                                             enum rnbd_access_mode access_mode)
 465 {
 466         int ret = -EPERM;
 467
 468         mutex_lock(&srv_dev->lock);
 469
 470         switch (access_mode) {
 471         case RNBD_ACCESS_RO:
 472                 ret = 0;
 473                 break;
 474         case RNBD_ACCESS_RW:
 475                 if (srv_dev->open_write_cnt == 0)  {
 476                         srv_dev->open_write_cnt++;
 477                         ret = 0;
 478                 } else {
 479                         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",
 480                                srv_dev->id, srv_sess->sessname,
 481                                srv_dev->open_write_cnt,
 482                                rnbd_access_mode_str(access_mode));
 483                 }
 484                 break;
 485         case RNBD_ACCESS_MIGRATION:
 486                 if (srv_dev->open_write_cnt < 2) {
 487                         srv_dev->open_write_cnt++;
 488                         ret = 0;
 489                 } else {
 490                         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",
 491                                srv_dev->id, srv_sess->sessname,
 492                                srv_dev->open_write_cnt,
 493                                rnbd_access_mode_str(access_mode));
 494                 }
 495                 break;
 496         default:
 497                 pr_err("Received mapping request for device '%s' on session %s with invalid access mode: %d\n",
 498                        srv_dev->id, srv_sess->sessname, access_mode);
 499                 ret = -EINVAL;
 500         }
 501
 502         mutex_unlock(&srv_dev->lock);
 503
 504         return ret;
 505 }
 506
 507 static struct rnbd_srv_dev *
 508 rnbd_srv_get_or_create_srv_dev(struct rnbd_dev *rnbd_dev,
 509                                 struct rnbd_srv_session *srv_sess,
 510                                 enum rnbd_access_mode access_mode)
 511 {
 512         int ret;
 513         struct rnbd_srv_dev *new_dev, *dev;
 514
 515         new_dev = rnbd_srv_init_srv_dev(rnbd_dev->name);
 516         if (IS_ERR(new_dev))
 517                 return new_dev;
 518
 519         dev = rnbd_srv_find_or_add_srv_dev(new_dev);
 520         if (dev != new_dev)
 521                 kfree(new_dev);
 522
 523         ret = rnbd_srv_check_update_open_perm(dev, srv_sess, access_mode);
 524         if (ret) {
 525                 rnbd_put_srv_dev(dev);
 526                 return ERR_PTR(ret);
 527         }
 528
 529         return dev;
 530 }
 531
 532 static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
 533                                         struct rnbd_srv_sess_dev *sess_dev)
 534 {
 535         struct rnbd_dev *rnbd_dev = sess_dev->rnbd_dev;
 536
 537         rsp->hdr.type = cpu_to_le16(RNBD_MSG_OPEN_RSP);
 538         rsp->device_id =
 539                 cpu_to_le32(sess_dev->device_id);
 540         rsp->nsectors =
 541                 cpu_to_le64(get_capacity(rnbd_dev->bdev->bd_disk));
 542         rsp->logical_block_size =
 543                 cpu_to_le16(bdev_logical_block_size(rnbd_dev->bdev));
 544         rsp->physical_block_size =
 545                 cpu_to_le16(bdev_physical_block_size(rnbd_dev->bdev));
 546         rsp->max_segments =
 547                 cpu_to_le16(rnbd_dev_get_max_segs(rnbd_dev));
 548         rsp->max_hw_sectors =
 549                 cpu_to_le32(rnbd_dev_get_max_hw_sects(rnbd_dev));
 550         rsp->max_write_same_sectors = 0;
 551         rsp->max_discard_sectors =
 552                 cpu_to_le32(rnbd_dev_get_max_discard_sects(rnbd_dev));
 553         rsp->discard_granularity =
 554                 cpu_to_le32(rnbd_dev_get_discard_granularity(rnbd_dev));
 555         rsp->discard_alignment =
 556                 cpu_to_le32(rnbd_dev_get_discard_alignment(rnbd_dev));
 557         rsp->secure_discard =
 558                 cpu_to_le16(rnbd_dev_get_secure_discard(rnbd_dev));
 559         rsp->cache_policy = 0;
 560         if (bdev_write_cache(rnbd_dev->bdev))
 561                 rsp->cache_policy |= RNBD_WRITEBACK;
 562         if (bdev_fua(rnbd_dev->bdev))
 563                 rsp->cache_policy |= RNBD_FUA;
 564 }
 565
 566 static struct rnbd_srv_sess_dev *
 567 rnbd_srv_create_set_sess_dev(struct rnbd_srv_session *srv_sess,
 568                               const struct rnbd_msg_open *open_msg,
 569                               struct rnbd_dev *rnbd_dev, fmode_t open_flags,
 570                               struct rnbd_srv_dev *srv_dev)
 571 {
 572         struct rnbd_srv_sess_dev *sdev = rnbd_sess_dev_alloc(srv_sess);
 573
 574         if (IS_ERR(sdev))
 575                 return sdev;
 576
 577         kref_init(&sdev->kref);
 578
 579         strscpy(sdev->pathname, open_msg->dev_name, sizeof(sdev->pathname));
 580
 581         sdev->rnbd_dev          = rnbd_dev;
 582         sdev->sess              = srv_sess;
 583         sdev->dev               = srv_dev;
 584         sdev->open_flags        = open_flags;
 585         sdev->access_mode       = open_msg->access_mode;
 586
 587         return sdev;
 588 }
 589
 590 static char *rnbd_srv_get_full_path(struct rnbd_srv_session *srv_sess,
 591                                      const char *dev_name)
 592 {
 593         char *full_path;
 594         char *a, *b;
 595
 596         full_path = kmalloc(PATH_MAX, GFP_KERNEL);
 597         if (!full_path)
 598                 return ERR_PTR(-ENOMEM);
 599
 600         /*
 601          * Replace %SESSNAME% with a real session name in order to
 602          * create device namespace.
 603          */
 604         a = strnstr(dev_search_path, "%SESSNAME%", sizeof(dev_search_path));
 605         if (a) {
 606                 int len = a - dev_search_path;
 607
 608                 len = snprintf(full_path, PATH_MAX, "%.*s/%s/%s", len,
 609                                dev_search_path, srv_sess->sessname, dev_name);
 610                 if (len >= PATH_MAX) {
 611                         pr_err("Too long path: %s, %s, %s\n",
 612                                dev_search_path, srv_sess->sessname, dev_name);
 613                         kfree(full_path);
 614                         return ERR_PTR(-EINVAL);
 615                 }
 616         } else {
 617                 snprintf(full_path, PATH_MAX, "%s/%s",
 618                          dev_search_path, dev_name);
 619         }
 620
 621         /* eliminitate duplicated slashes */
 622         a = strchr(full_path, '/');
 623         b = a;
 624         while (*b != '\0') {
 625                 if (*b == '/' && *a == '/') {
 626                         b++;
 627                 } else {
 628                         a++;
 629                         *a = *b;
 630                         b++;
 631                 }
 632         }
 633         a++;
 634         *a = '\0';
 635
 636         return full_path;
 637 }
 638
 639 static int process_msg_sess_info(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 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         fmode_t open_flags;
 689         char *full_path;
 690         struct rnbd_dev *rnbd_dev;
 691         struct rnbd_msg_open_rsp *rsp = data;
 692
 693         pr_debug("Open message received: session='%s' path='%s' access_mode=%d\n",
 694                  srv_sess->sessname, open_msg->dev_name,
 695                  open_msg->access_mode);
 696         open_flags = FMODE_READ;
 697         if (open_msg->access_mode != RNBD_ACCESS_RO)
 698                 open_flags |= FMODE_WRITE;
 699
 700         mutex_lock(&srv_sess->lock);
 701
 702         srv_sess_dev = find_srv_sess_dev(srv_sess, open_msg->dev_name);
 703         if (srv_sess_dev)
 704                 goto fill_response;
 705
 706         if ((strlen(dev_search_path) + strlen(open_msg->dev_name))
 707             >= PATH_MAX) {
 708                 pr_err("Opening device for session %s failed, device path too long. '%s/%s' is longer than PATH_MAX (%d)\n",
 709                        srv_sess->sessname, dev_search_path, open_msg->dev_name,
 710                        PATH_MAX);
 711                 ret = -EINVAL;
 712                 goto reject;
 713         }
 714         if (strstr(open_msg->dev_name, "..")) {
 715                 pr_err("Opening device for session %s failed, device path %s contains relative path ..\n",
 716                        srv_sess->sessname, open_msg->dev_name);
 717                 ret = -EINVAL;
 718                 goto reject;
 719         }
 720         full_path = rnbd_srv_get_full_path(srv_sess, open_msg->dev_name);
 721         if (IS_ERR(full_path)) {
 722                 ret = PTR_ERR(full_path);
 723                 pr_err("Opening device '%s' for client %s failed, failed to get device full path, err: %d\n",
 724                        open_msg->dev_name, srv_sess->sessname, ret);
 725                 goto reject;
 726         }
 727
 728         rnbd_dev = rnbd_dev_open(full_path, open_flags);
 729         if (IS_ERR(rnbd_dev)) {
 730                 pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %ld\n",
 731                        full_path, srv_sess->sessname, PTR_ERR(rnbd_dev));
 732                 ret = PTR_ERR(rnbd_dev);
 733                 goto free_path;
 734         }
 735
 736         srv_dev = rnbd_srv_get_or_create_srv_dev(rnbd_dev, srv_sess,
 737                                                   open_msg->access_mode);
 738         if (IS_ERR(srv_dev)) {
 739                 pr_err("Opening device '%s' on session %s failed, creating srv_dev failed, err: %ld\n",
 740                        full_path, srv_sess->sessname, PTR_ERR(srv_dev));
 741                 ret = PTR_ERR(srv_dev);
 742                 goto rnbd_dev_close;
 743         }
 744
 745         srv_sess_dev = rnbd_srv_create_set_sess_dev(srv_sess, open_msg,
 746                                                      rnbd_dev, open_flags,
 747                                                      srv_dev);
 748         if (IS_ERR(srv_sess_dev)) {
 749                 pr_err("Opening device '%s' on session %s failed, creating sess_dev failed, err: %ld\n",
 750                        full_path, srv_sess->sessname, PTR_ERR(srv_sess_dev));
 751                 ret = PTR_ERR(srv_sess_dev);
 752                 goto srv_dev_put;
 753         }
 754
 755         /* Create the srv_dev sysfs files if they haven't been created yet. The
 756          * reason to delay the creation is not to create the sysfs files before
 757          * we are sure the device can be opened.
 758          */
 759         mutex_lock(&srv_dev->lock);
 760         if (!srv_dev->dev_kobj.state_in_sysfs) {
 761                 ret = rnbd_srv_create_dev_sysfs(srv_dev, rnbd_dev->bdev,
 762                                                  rnbd_dev->name);
 763                 if (ret) {
 764                         mutex_unlock(&srv_dev->lock);
 765                         rnbd_srv_err(srv_sess_dev,
 766                                       "Opening device failed, failed to create device sysfs files, err: %d\n",
 767                                       ret);
 768                         goto free_srv_sess_dev;
 769                 }
 770         }
 771
 772         ret = rnbd_srv_create_dev_session_sysfs(srv_sess_dev);
 773         if (ret) {
 774                 mutex_unlock(&srv_dev->lock);
 775                 rnbd_srv_err(srv_sess_dev,
 776                               "Opening device failed, failed to create dev client sysfs files, err: %d\n",
 777                               ret);
 778                 goto free_srv_sess_dev;
 779         }
 780
 781         list_add(&srv_sess_dev->dev_list, &srv_dev->sess_dev_list);
 782         mutex_unlock(&srv_dev->lock);
 783
 784         list_add(&srv_sess_dev->sess_list, &srv_sess->sess_dev_list);
 785
 786         rnbd_srv_info(srv_sess_dev, "Opened device '%s'\n", srv_dev->id);
 787
 788         kfree(full_path);
 789
 790 fill_response:
 791         rnbd_srv_fill_msg_open_rsp(rsp, srv_sess_dev);
 792         mutex_unlock(&srv_sess->lock);
 793         return 0;
 794
 795 free_srv_sess_dev:
 796         xa_erase(&srv_sess->index_idr, srv_sess_dev->device_id);
 797         synchronize_rcu();
 798         kfree(srv_sess_dev);
 799 srv_dev_put:
 800         if (open_msg->access_mode != RNBD_ACCESS_RO) {
 801                 mutex_lock(&srv_dev->lock);
 802                 srv_dev->open_write_cnt--;
 803                 mutex_unlock(&srv_dev->lock);
 804         }
 805         rnbd_put_srv_dev(srv_dev);
 806 rnbd_dev_close:
 807         rnbd_dev_close(rnbd_dev);
 808 free_path:
 809         kfree(full_path);
 810 reject:
 811         mutex_unlock(&srv_sess->lock);
 812         return ret;
 813 }
 814
 815 static struct rtrs_srv_ctx *rtrs_ctx;
 816
 817 static struct rtrs_srv_ops rtrs_ops;
 818 static int __init rnbd_srv_init_module(void)
 819 {
 820         int err;
 821
 822         BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
 823         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
 824         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
 825         BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
 826         BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
 827         BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
 828         rtrs_ops = (struct rtrs_srv_ops) {
 829                 .rdma_ev = rnbd_srv_rdma_ev,
 830                 .link_ev = rnbd_srv_link_ev,
 831         };
 832         rtrs_ctx = rtrs_srv_open(&rtrs_ops, port_nr);
 833         if (IS_ERR(rtrs_ctx)) {
 834                 err = PTR_ERR(rtrs_ctx);
 835                 pr_err("rtrs_srv_open(), err: %d\n", err);
 836                 return err;
 837         }
 838
 839         err = rnbd_srv_create_sysfs_files();
 840         if (err) {
 841                 pr_err("rnbd_srv_create_sysfs_files(), err: %d\n", err);
 842                 rtrs_srv_close(rtrs_ctx);
 843                 return err;
 844         }
 845
 846         return 0;
 847 }
 848
 849 static void __exit rnbd_srv_cleanup_module(void)
 850 {
 851         rtrs_srv_close(rtrs_ctx);
 852         WARN_ON(!list_empty(&sess_list));
 853         rnbd_srv_destroy_sysfs_files();
 854 }
 855
 856 module_init(rnbd_srv_init_module);
 857 module_exit(rnbd_srv_cleanup_module);