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 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 rnbd_dev_blk_io *io;
 127         struct bio *bio;
 128         short prio;
 129
 130         priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 131         if (!priv)
 132                 return -ENOMEM;
 133
 134         dev_id = le32_to_cpu(msg->device_id);
 135
 136         sess_dev = rnbd_get_sess_dev(dev_id, srv_sess);
 137         if (IS_ERR(sess_dev)) {
 138                 pr_err_ratelimited("Got I/O request on session %s for unknown device id %d\n",
 139                                    srv_sess->sessname, dev_id);
 140                 err = -ENOTCONN;
 141                 goto err;
 142         }
 143
 144         priv->sess_dev = sess_dev;
 145         priv->id = id;
 146
 147         /* Generate bio with pages pointing to the rdma buffer */
 148         bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, GFP_KERNEL);
 149         if (IS_ERR(bio)) {
 150                 err = PTR_ERR(bio);
 151                 rnbd_srv_err(sess_dev, "Failed to generate bio, err: %d\n", err);
 152                 goto sess_dev_put;
 153         }
 154
 155         io = container_of(bio, struct rnbd_dev_blk_io, bio);
 156         io->dev = sess_dev->rnbd_dev;
 157         io->priv = priv;
 158
 159         bio->bi_end_io = rnbd_dev_bi_end_io;
 160         bio->bi_private = io;
 161         bio->bi_opf = rnbd_to_bio_flags(le32_to_cpu(msg->rw));
 162         bio->bi_iter.bi_sector = le64_to_cpu(msg->sector);
 163         bio->bi_iter.bi_size = le32_to_cpu(msg->bi_size);
 164         prio = srv_sess->ver < RNBD_PROTO_VER_MAJOR ||
 165                usrlen < sizeof(*msg) ? 0 : le16_to_cpu(msg->prio);
 166         bio_set_prio(bio, prio);
 167         bio_set_dev(bio, sess_dev->rnbd_dev->bdev);
 168
 169         submit_bio(bio);
 170
 171         return 0;
 172
 173 sess_dev_put:
 174         rnbd_put_sess_dev(sess_dev);
 175 err:
 176         kfree(priv);
 177         return err;
 178 }
 179
 180 static void destroy_device(struct kref *kref)
 181 {
 182         struct rnbd_srv_dev *dev = container_of(kref, struct rnbd_srv_dev, kref);
 183
 184         WARN_ONCE(!list_empty(&dev->sess_dev_list),
 185                   "Device %s is being destroyed but still in use!\n",
 186                   dev->id);
 187
 188         spin_lock(&dev_lock);
 189         list_del(&dev->list);
 190         spin_unlock(&dev_lock);
 191
 192         mutex_destroy(&dev->lock);
 193         if (dev->dev_kobj.state_in_sysfs)
 194                 /*
 195                  * Destroy kobj only if it was really created.
 196                  */
 197                 rnbd_srv_destroy_dev_sysfs(dev);
 198         else
 199                 kfree(dev);
 200 }
 201
 202 static void rnbd_put_srv_dev(struct rnbd_srv_dev *dev)
 203 {
 204         kref_put(&dev->kref, destroy_device);
 205 }
 206
 207 void rnbd_destroy_sess_dev(struct rnbd_srv_sess_dev *sess_dev, bool keep_id)
 208 {
 209         DECLARE_COMPLETION_ONSTACK(dc);
 210
 211         if (keep_id)
 212                 /* free the resources for the id but don't  */
 213                 /* allow to re-use the id itself because it */
 214                 /* is still used by the client              */
 215                 xa_cmpxchg(&sess_dev->sess->index_idr, sess_dev->device_id,
 216                            sess_dev, NULL, 0);
 217         else
 218                 xa_erase(&sess_dev->sess->index_idr, sess_dev->device_id);
 219         synchronize_rcu();
 220
 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         strscpy(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 void rnbd_srv_sess_dev_force_close(struct rnbd_srv_sess_dev *sess_dev,
 332                                    struct kobj_attribute *attr)
 333 {
 334         struct rnbd_srv_session *sess = sess_dev->sess;
 335
 336         sess_dev->keep_id = true;
 337         /* It is already started to close by client's close message. */
 338         if (!mutex_trylock(&sess->lock))
 339                 return;
 340         /* first remove sysfs itself to avoid deadlock */
 341         sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
 342         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 343         mutex_unlock(&sess->lock);
 344 }
 345
 346 static int process_msg_close(struct rnbd_srv_session *srv_sess,
 347                              void *data, size_t datalen, const void *usr,
 348                              size_t usrlen)
 349 {
 350         const struct rnbd_msg_close *close_msg = usr;
 351         struct rnbd_srv_sess_dev *sess_dev;
 352
 353         sess_dev = rnbd_get_sess_dev(le32_to_cpu(close_msg->device_id),
 354                                       srv_sess);
 355         if (IS_ERR(sess_dev))
 356                 return 0;
 357
 358         rnbd_put_sess_dev(sess_dev);
 359         mutex_lock(&srv_sess->lock);
 360         rnbd_srv_destroy_dev_session_sysfs(sess_dev);
 361         mutex_unlock(&srv_sess->lock);
 362         return 0;
 363 }
 364
 365 static int process_msg_open(struct rnbd_srv_session *srv_sess,
 366                             const void *msg, size_t len,
 367                             void *data, size_t datalen);
 368
 369 static int process_msg_sess_info(struct rnbd_srv_session *srv_sess,
 370                                  const void *msg, size_t len,
 371                                  void *data, size_t datalen);
 372
 373 static int rnbd_srv_rdma_ev(void *priv,
 374                             struct rtrs_srv_op *id, int dir,
 375                             void *data, size_t datalen, const void *usr,
 376                             size_t usrlen)
 377 {
 378         struct rnbd_srv_session *srv_sess = priv;
 379         const struct rnbd_msg_hdr *hdr = usr;
 380         int ret = 0;
 381         u16 type;
 382
 383         if (WARN_ON_ONCE(!srv_sess))
 384                 return -ENODEV;
 385
 386         type = le16_to_cpu(hdr->type);
 387
 388         switch (type) {
 389         case RNBD_MSG_IO:
 390                 return process_rdma(srv_sess, id, data, datalen, usr, usrlen);
 391         case RNBD_MSG_CLOSE:
 392                 ret = process_msg_close(srv_sess, data, datalen, usr, usrlen);
 393                 break;
 394         case RNBD_MSG_OPEN:
 395                 ret = process_msg_open(srv_sess, usr, usrlen, data, datalen);
 396                 break;
 397         case RNBD_MSG_SESS_INFO:
 398                 ret = process_msg_sess_info(srv_sess, usr, usrlen, data,
 399                                             datalen);
 400                 break;
 401         default:
 402                 pr_warn("Received unexpected message type %d with dir %d from session %s\n",
 403                         type, dir, srv_sess->sessname);
 404                 return -EINVAL;
 405         }
 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(const char *id)
 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         strscpy(dev->id, id, sizeof(dev->id));
 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->id, new_dev->id, sizeof(dev->id))) {
 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 = -EPERM;
 477
 478         mutex_lock(&srv_dev->lock);
 479
 480         switch (access_mode) {
 481         case RNBD_ACCESS_RO:
 482                 ret = 0;
 483                 break;
 484         case RNBD_ACCESS_RW:
 485                 if (srv_dev->open_write_cnt == 0)  {
 486                         srv_dev->open_write_cnt++;
 487                         ret = 0;
 488                 } else {
 489                         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",
 490                                srv_dev->id, srv_sess->sessname,
 491                                srv_dev->open_write_cnt,
 492                                rnbd_access_mode_str(access_mode));
 493                 }
 494                 break;
 495         case RNBD_ACCESS_MIGRATION:
 496                 if (srv_dev->open_write_cnt < 2) {
 497                         srv_dev->open_write_cnt++;
 498                         ret = 0;
 499                 } else {
 500                         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",
 501                                srv_dev->id, srv_sess->sessname,
 502                                srv_dev->open_write_cnt,
 503                                rnbd_access_mode_str(access_mode));
 504                 }
 505                 break;
 506         default:
 507                 pr_err("Received mapping request for device '%s' on session %s with invalid access mode: %d\n",
 508                        srv_dev->id, srv_sess->sessname, access_mode);
 509                 ret = -EINVAL;
 510         }
 511
 512         mutex_unlock(&srv_dev->lock);
 513
 514         return ret;
 515 }
 516
 517 static struct rnbd_srv_dev *
 518 rnbd_srv_get_or_create_srv_dev(struct rnbd_dev *rnbd_dev,
 519                                 struct rnbd_srv_session *srv_sess,
 520                                 enum rnbd_access_mode access_mode)
 521 {
 522         int ret;
 523         struct rnbd_srv_dev *new_dev, *dev;
 524
 525         new_dev = rnbd_srv_init_srv_dev(rnbd_dev->name);
 526         if (IS_ERR(new_dev))
 527                 return new_dev;
 528
 529         dev = rnbd_srv_find_or_add_srv_dev(new_dev);
 530         if (dev != new_dev)
 531                 kfree(new_dev);
 532
 533         ret = rnbd_srv_check_update_open_perm(dev, srv_sess, access_mode);
 534         if (ret) {
 535                 rnbd_put_srv_dev(dev);
 536                 return ERR_PTR(ret);
 537         }
 538
 539         return dev;
 540 }
 541
 542 static void rnbd_srv_fill_msg_open_rsp(struct rnbd_msg_open_rsp *rsp,
 543                                         struct rnbd_srv_sess_dev *sess_dev)
 544 {
 545         struct rnbd_dev *rnbd_dev = sess_dev->rnbd_dev;
 546         struct request_queue *q = bdev_get_queue(rnbd_dev->bdev);
 547
 548         rsp->hdr.type = cpu_to_le16(RNBD_MSG_OPEN_RSP);
 549         rsp->device_id =
 550                 cpu_to_le32(sess_dev->device_id);
 551         rsp->nsectors =
 552                 cpu_to_le64(get_capacity(rnbd_dev->bdev->bd_disk));
 553         rsp->logical_block_size =
 554                 cpu_to_le16(bdev_logical_block_size(rnbd_dev->bdev));
 555         rsp->physical_block_size =
 556                 cpu_to_le16(bdev_physical_block_size(rnbd_dev->bdev));
 557         rsp->max_segments =
 558                 cpu_to_le16(rnbd_dev_get_max_segs(rnbd_dev));
 559         rsp->max_hw_sectors =
 560                 cpu_to_le32(rnbd_dev_get_max_hw_sects(rnbd_dev));
 561         rsp->max_write_same_sectors =
 562                 cpu_to_le32(bdev_write_same(rnbd_dev->bdev));
 563         rsp->max_discard_sectors =
 564                 cpu_to_le32(rnbd_dev_get_max_discard_sects(rnbd_dev));
 565         rsp->discard_granularity =
 566                 cpu_to_le32(rnbd_dev_get_discard_granularity(rnbd_dev));
 567         rsp->discard_alignment =
 568                 cpu_to_le32(rnbd_dev_get_discard_alignment(rnbd_dev));
 569         rsp->secure_discard =
 570                 cpu_to_le16(rnbd_dev_get_secure_discard(rnbd_dev));
 571         rsp->rotational = !blk_queue_nonrot(q);
 572         rsp->cache_policy = 0;
 573         if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
 574                 rsp->cache_policy |= RNBD_WRITEBACK;
 575         if (blk_queue_fua(q))
 576                 rsp->cache_policy |= RNBD_FUA;
 577 }
 578
 579 static struct rnbd_srv_sess_dev *
 580 rnbd_srv_create_set_sess_dev(struct rnbd_srv_session *srv_sess,
 581                               const struct rnbd_msg_open *open_msg,
 582                               struct rnbd_dev *rnbd_dev, fmode_t open_flags,
 583                               struct rnbd_srv_dev *srv_dev)
 584 {
 585         struct rnbd_srv_sess_dev *sdev = rnbd_sess_dev_alloc(srv_sess);
 586
 587         if (IS_ERR(sdev))
 588                 return sdev;
 589
 590         kref_init(&sdev->kref);
 591
 592         strscpy(sdev->pathname, open_msg->dev_name, sizeof(sdev->pathname));
 593
 594         sdev->rnbd_dev          = rnbd_dev;
 595         sdev->sess              = srv_sess;
 596         sdev->dev               = srv_dev;
 597         sdev->open_flags        = open_flags;
 598         sdev->access_mode       = open_msg->access_mode;
 599
 600         return sdev;
 601 }
 602
 603 static char *rnbd_srv_get_full_path(struct rnbd_srv_session *srv_sess,
 604                                      const char *dev_name)
 605 {
 606         char *full_path;
 607         char *a, *b;
 608
 609         full_path = kmalloc(PATH_MAX, GFP_KERNEL);
 610         if (!full_path)
 611                 return ERR_PTR(-ENOMEM);
 612
 613         /*
 614          * Replace %SESSNAME% with a real session name in order to
 615          * create device namespace.
 616          */
 617         a = strnstr(dev_search_path, "%SESSNAME%", sizeof(dev_search_path));
 618         if (a) {
 619                 int len = a - dev_search_path;
 620
 621                 len = snprintf(full_path, PATH_MAX, "%.*s/%s/%s", len,
 622                                dev_search_path, srv_sess->sessname, dev_name);
 623                 if (len >= PATH_MAX) {
 624                         pr_err("Too long path: %s, %s, %s\n",
 625                                dev_search_path, srv_sess->sessname, dev_name);
 626                         kfree(full_path);
 627                         return ERR_PTR(-EINVAL);
 628                 }
 629         } else {
 630                 snprintf(full_path, PATH_MAX, "%s/%s",
 631                          dev_search_path, dev_name);
 632         }
 633
 634         /* eliminitate duplicated slashes */
 635         a = strchr(full_path, '/');
 636         b = a;
 637         while (*b != '\0') {
 638                 if (*b == '/' && *a == '/') {
 639                         b++;
 640                 } else {
 641                         a++;
 642                         *a = *b;
 643                         b++;
 644                 }
 645         }
 646         a++;
 647         *a = '\0';
 648
 649         return full_path;
 650 }
 651
 652 static int process_msg_sess_info(struct rnbd_srv_session *srv_sess,
 653                                  const void *msg, size_t len,
 654                                  void *data, size_t datalen)
 655 {
 656         const struct rnbd_msg_sess_info *sess_info_msg = msg;
 657         struct rnbd_msg_sess_info_rsp *rsp = data;
 658
 659         srv_sess->ver = min_t(u8, sess_info_msg->ver, RNBD_PROTO_VER_MAJOR);
 660         pr_debug("Session %s using protocol version %d (client version: %d, server version: %d)\n",
 661                  srv_sess->sessname, srv_sess->ver,
 662                  sess_info_msg->ver, RNBD_PROTO_VER_MAJOR);
 663
 664         rsp->hdr.type = cpu_to_le16(RNBD_MSG_SESS_INFO_RSP);
 665         rsp->ver = srv_sess->ver;
 666
 667         return 0;
 668 }
 669
 670 /**
 671  * find_srv_sess_dev() - a dev is already opened by this name
 672  * @srv_sess:   the session to search.
 673  * @dev_name:   string containing the name of the device.
 674  *
 675  * Return struct rnbd_srv_sess_dev if srv_sess already opened the dev_name
 676  * NULL if the session didn't open the device yet.
 677  */
 678 static struct rnbd_srv_sess_dev *
 679 find_srv_sess_dev(struct rnbd_srv_session *srv_sess, const char *dev_name)
 680 {
 681         struct rnbd_srv_sess_dev *sess_dev;
 682
 683         if (list_empty(&srv_sess->sess_dev_list))
 684                 return NULL;
 685
 686         list_for_each_entry(sess_dev, &srv_sess->sess_dev_list, sess_list)
 687                 if (!strcmp(sess_dev->pathname, dev_name))
 688                         return sess_dev;
 689
 690         return NULL;
 691 }
 692
 693 static int process_msg_open(struct rnbd_srv_session *srv_sess,
 694                             const void *msg, size_t len,
 695                             void *data, size_t datalen)
 696 {
 697         int ret;
 698         struct rnbd_srv_dev *srv_dev;
 699         struct rnbd_srv_sess_dev *srv_sess_dev;
 700         const struct rnbd_msg_open *open_msg = msg;
 701         fmode_t open_flags;
 702         char *full_path;
 703         struct rnbd_dev *rnbd_dev;
 704         struct rnbd_msg_open_rsp *rsp = data;
 705
 706         pr_debug("Open message received: session='%s' path='%s' access_mode=%d\n",
 707                  srv_sess->sessname, open_msg->dev_name,
 708                  open_msg->access_mode);
 709         open_flags = FMODE_READ;
 710         if (open_msg->access_mode != RNBD_ACCESS_RO)
 711                 open_flags |= FMODE_WRITE;
 712
 713         mutex_lock(&srv_sess->lock);
 714
 715         srv_sess_dev = find_srv_sess_dev(srv_sess, open_msg->dev_name);
 716         if (srv_sess_dev)
 717                 goto fill_response;
 718
 719         if ((strlen(dev_search_path) + strlen(open_msg->dev_name))
 720             >= PATH_MAX) {
 721                 pr_err("Opening device for session %s failed, device path too long. '%s/%s' is longer than PATH_MAX (%d)\n",
 722                        srv_sess->sessname, dev_search_path, open_msg->dev_name,
 723                        PATH_MAX);
 724                 ret = -EINVAL;
 725                 goto reject;
 726         }
 727         if (strstr(open_msg->dev_name, "..")) {
 728                 pr_err("Opening device for session %s failed, device path %s contains relative path ..\n",
 729                        srv_sess->sessname, open_msg->dev_name);
 730                 ret = -EINVAL;
 731                 goto reject;
 732         }
 733         full_path = rnbd_srv_get_full_path(srv_sess, open_msg->dev_name);
 734         if (IS_ERR(full_path)) {
 735                 ret = PTR_ERR(full_path);
 736                 pr_err("Opening device '%s' for client %s failed, failed to get device full path, err: %d\n",
 737                        open_msg->dev_name, srv_sess->sessname, ret);
 738                 goto reject;
 739         }
 740
 741         rnbd_dev = rnbd_dev_open(full_path, open_flags,
 742                                  &srv_sess->sess_bio_set);
 743         if (IS_ERR(rnbd_dev)) {
 744                 pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %ld\n",
 745                        full_path, srv_sess->sessname, PTR_ERR(rnbd_dev));
 746                 ret = PTR_ERR(rnbd_dev);
 747                 goto free_path;
 748         }
 749
 750         srv_dev = rnbd_srv_get_or_create_srv_dev(rnbd_dev, srv_sess,
 751                                                   open_msg->access_mode);
 752         if (IS_ERR(srv_dev)) {
 753                 pr_err("Opening device '%s' on session %s failed, creating srv_dev failed, err: %ld\n",
 754                        full_path, srv_sess->sessname, PTR_ERR(srv_dev));
 755                 ret = PTR_ERR(srv_dev);
 756                 goto rnbd_dev_close;
 757         }
 758
 759         srv_sess_dev = rnbd_srv_create_set_sess_dev(srv_sess, open_msg,
 760                                                      rnbd_dev, open_flags,
 761                                                      srv_dev);
 762         if (IS_ERR(srv_sess_dev)) {
 763                 pr_err("Opening device '%s' on session %s failed, creating sess_dev failed, err: %ld\n",
 764                        full_path, srv_sess->sessname, PTR_ERR(srv_sess_dev));
 765                 ret = PTR_ERR(srv_sess_dev);
 766                 goto srv_dev_put;
 767         }
 768
 769         /* Create the srv_dev sysfs files if they haven't been created yet. The
 770          * reason to delay the creation is not to create the sysfs files before
 771          * we are sure the device can be opened.
 772          */
 773         mutex_lock(&srv_dev->lock);
 774         if (!srv_dev->dev_kobj.state_in_sysfs) {
 775                 ret = rnbd_srv_create_dev_sysfs(srv_dev, rnbd_dev->bdev,
 776                                                  rnbd_dev->name);
 777                 if (ret) {
 778                         mutex_unlock(&srv_dev->lock);
 779                         rnbd_srv_err(srv_sess_dev,
 780                                       "Opening device failed, failed to create device sysfs files, err: %d\n",
 781                                       ret);
 782                         goto free_srv_sess_dev;
 783                 }
 784         }
 785
 786         ret = rnbd_srv_create_dev_session_sysfs(srv_sess_dev);
 787         if (ret) {
 788                 mutex_unlock(&srv_dev->lock);
 789                 rnbd_srv_err(srv_sess_dev,
 790                               "Opening device failed, failed to create dev client sysfs files, err: %d\n",
 791                               ret);
 792                 goto free_srv_sess_dev;
 793         }
 794
 795         list_add(&srv_sess_dev->dev_list, &srv_dev->sess_dev_list);
 796         mutex_unlock(&srv_dev->lock);
 797
 798         list_add(&srv_sess_dev->sess_list, &srv_sess->sess_dev_list);
 799
 800         rnbd_srv_info(srv_sess_dev, "Opened device '%s'\n", srv_dev->id);
 801
 802         kfree(full_path);
 803
 804 fill_response:
 805         rnbd_srv_fill_msg_open_rsp(rsp, srv_sess_dev);
 806         mutex_unlock(&srv_sess->lock);
 807         return 0;
 808
 809 free_srv_sess_dev:
 810         xa_erase(&srv_sess->index_idr, srv_sess_dev->device_id);
 811         synchronize_rcu();
 812         kfree(srv_sess_dev);
 813 srv_dev_put:
 814         if (open_msg->access_mode != RNBD_ACCESS_RO) {
 815                 mutex_lock(&srv_dev->lock);
 816                 srv_dev->open_write_cnt--;
 817                 mutex_unlock(&srv_dev->lock);
 818         }
 819         rnbd_put_srv_dev(srv_dev);
 820 rnbd_dev_close:
 821         rnbd_dev_close(rnbd_dev);
 822 free_path:
 823         kfree(full_path);
 824 reject:
 825         mutex_unlock(&srv_sess->lock);
 826         return ret;
 827 }
 828
 829 static struct rtrs_srv_ctx *rtrs_ctx;
 830
 831 static struct rtrs_srv_ops rtrs_ops;
 832 static int __init rnbd_srv_init_module(void)
 833 {
 834         int err;
 835
 836         BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
 837         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
 838         BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
 839         BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
 840         BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
 841         BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
 842         rtrs_ops = (struct rtrs_srv_ops) {
 843                 .rdma_ev = rnbd_srv_rdma_ev,
 844                 .link_ev = rnbd_srv_link_ev,
 845         };
 846         rtrs_ctx = rtrs_srv_open(&rtrs_ops, port_nr);
 847         if (IS_ERR(rtrs_ctx)) {
 848                 err = PTR_ERR(rtrs_ctx);
 849                 pr_err("rtrs_srv_open(), err: %d\n", err);
 850                 return err;
 851         }
 852
 853         err = rnbd_srv_create_sysfs_files();
 854         if (err) {
 855                 pr_err("rnbd_srv_create_sysfs_files(), err: %d\n", err);
 856                 rtrs_srv_close(rtrs_ctx);
 857                 return err;
 858         }
 859
 860         return 0;
 861 }
 862
 863 static void __exit rnbd_srv_cleanup_module(void)
 864 {
 865         rtrs_srv_close(rtrs_ctx);
 866         WARN_ON(!list_empty(&sess_list));
 867         rnbd_srv_destroy_sysfs_files();
 868 }
 869
 870 module_init(rnbd_srv_init_module);
 871 module_exit(rnbd_srv_cleanup_module);