block/nfs.c

   1 /*
   2  * QEMU Block driver for native access to files on NFS shares
   3  *
   4  * Copyright (c) 2014-2017 Peter Lieven <pl@kamp.de>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu/osdep.h"
  26
  27 #if !defined(_WIN32)
  28 #include <poll.h>
  29 #endif
  30 #include "qemu/config-file.h"
  31 #include "qemu/error-report.h"
  32 #include "qapi/error.h"
  33 #include "block/block-io.h"
  34 #include "block/block_int.h"
  35 #include "block/qdict.h"
  36 #include "trace.h"
  37 #include "qemu/iov.h"
  38 #include "qemu/main-loop.h"
  39 #include "qemu/module.h"
  40 #include "qemu/option.h"
  41 #include "qemu/cutils.h"
  42 #include "sysemu/replay.h"
  43 #include "qapi/qapi-visit-block-core.h"
  44 #include "qapi/qmp/qdict.h"
  45 #include "qapi/qmp/qstring.h"
  46 #include "qapi/qobject-input-visitor.h"
  47 #include "qapi/qobject-output-visitor.h"
  48 #include <nfsc/libnfs.h>
  49
  50
  51 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  52 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  53 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  54
  55 typedef struct NFSClient {
  56     struct nfs_context *context;
  57     struct nfsfh *fh;
  58     int events;
  59     bool has_zero_init;
  60     AioContext *aio_context;
  61     QemuMutex mutex;
  62     uint64_t st_blocks;
  63     bool cache_used;
  64     NFSServer *server;
  65     char *path;
  66     int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug;
  67 } NFSClient;
  68
  69 typedef struct NFSRPC {
  70     BlockDriverState *bs;
  71     int ret;
  72     int complete;
  73     QEMUIOVector *iov;
  74     struct stat *st;
  75     Coroutine *co;
  76     NFSClient *client;
  77 } NFSRPC;
  78
  79 static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
  80 {
  81     g_autoptr(GUri) uri = g_uri_parse(filename, G_URI_FLAGS_NONE, NULL);
  82     GUriParamsIter qp;
  83     const char *uri_server, *uri_path, *uri_query;
  84     char *qp_name, *qp_value;
  85     GError *gerror = NULL;
  86
  87     if (!uri) {
  88         error_setg(errp, "Invalid URI specified");
  89         return -EINVAL;
  90     }
  91     if (!g_str_equal(g_uri_get_scheme(uri), "nfs")) {
  92         error_setg(errp, "URI scheme must be 'nfs'");
  93         return -EINVAL;
  94     }
  95
  96     uri_server = g_uri_get_host(uri);
  97     if (!uri_server || !uri_server[0]) {
  98         error_setg(errp, "missing hostname in URI");
  99         return -EINVAL;
 100     }
 101
 102     uri_path = g_uri_get_path(uri);
 103     if (!uri_path || !uri_path[0]) {
 104         error_setg(errp, "missing file path in URI");
 105         return -EINVAL;
 106     }
 107
 108     qdict_put_str(options, "server.host", uri_server);
 109     qdict_put_str(options, "server.type", "inet");
 110     qdict_put_str(options, "path", uri_path);
 111
 112     uri_query = g_uri_get_query(uri);
 113     if (uri_query) {
 114         g_uri_params_iter_init(&qp, uri_query, -1, "&", G_URI_PARAMS_NONE);
 115         while (g_uri_params_iter_next(&qp, &qp_name, &qp_value, &gerror)) {
 116             uint64_t val;
 117             if (!qp_name || gerror) {
 118                 error_setg(errp, "Failed to parse NFS parameter");
 119                 return -EINVAL;
 120             }
 121             if (!qp_value) {
 122                 error_setg(errp, "Value for NFS parameter expected: %s",
 123                            qp_name);
 124                 return -EINVAL;
 125             }
 126             if (parse_uint_full(qp_value, 0, &val)) {
 127                 error_setg(errp, "Invalid value for NFS parameter: %s",
 128                            qp_name);
 129                 return -EINVAL;
 130             }
 131             if (g_str_equal(qp_name, "uid")) {
 132                 qdict_put_str(options, "user", qp_value);
 133             } else if (g_str_equal(qp_name, "gid")) {
 134                 qdict_put_str(options, "group", qp_value);
 135             } else if (g_str_equal(qp_name, "tcp-syncnt")) {
 136                 qdict_put_str(options, "tcp-syn-count", qp_value);
 137             } else if (g_str_equal(qp_name, "readahead")) {
 138                 qdict_put_str(options, "readahead-size", qp_value);
 139             } else if (g_str_equal(qp_name, "pagecache")) {
 140                 qdict_put_str(options, "page-cache-size", qp_value);
 141             } else if (g_str_equal(qp_name, "debug")) {
 142                 qdict_put_str(options, "debug", qp_value);
 143             } else {
 144                 error_setg(errp, "Unknown NFS parameter name: %s", qp_name);
 145                 return -EINVAL;
 146             }
 147         }
 148     }
 149
 150     return 0;
 151 }
 152
 153 static bool nfs_has_filename_options_conflict(QDict *options, Error **errp)
 154 {
 155     const QDictEntry *qe;
 156
 157     for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
 158         if (!strcmp(qe->key, "host") ||
 159             !strcmp(qe->key, "path") ||
 160             !strcmp(qe->key, "user") ||
 161             !strcmp(qe->key, "group") ||
 162             !strcmp(qe->key, "tcp-syn-count") ||
 163             !strcmp(qe->key, "readahead-size") ||
 164             !strcmp(qe->key, "page-cache-size") ||
 165             !strcmp(qe->key, "debug") ||
 166             strstart(qe->key, "server.", NULL))
 167         {
 168             error_setg(errp, "Option %s cannot be used with a filename",
 169                        qe->key);
 170             return true;
 171         }
 172     }
 173
 174     return false;
 175 }
 176
 177 static void nfs_parse_filename(const char *filename, QDict *options,
 178                                Error **errp)
 179 {
 180     if (nfs_has_filename_options_conflict(options, errp)) {
 181         return;
 182     }
 183
 184     nfs_parse_uri(filename, options, errp);
 185 }
 186
 187 static void nfs_process_read(void *arg);
 188 static void nfs_process_write(void *arg);
 189
 190 /* Called with QemuMutex held.  */
 191 static void nfs_set_events(NFSClient *client)
 192 {
 193     int ev = nfs_which_events(client->context);
 194     if (ev != client->events) {
 195         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 196                            (ev & POLLIN) ? nfs_process_read : NULL,
 197                            (ev & POLLOUT) ? nfs_process_write : NULL,
 198                            NULL, NULL, client);
 199
 200     }
 201     client->events = ev;
 202 }
 203
 204 static void nfs_process_read(void *arg)
 205 {
 206     NFSClient *client = arg;
 207
 208     qemu_mutex_lock(&client->mutex);
 209     nfs_service(client->context, POLLIN);
 210     nfs_set_events(client);
 211     qemu_mutex_unlock(&client->mutex);
 212 }
 213
 214 static void nfs_process_write(void *arg)
 215 {
 216     NFSClient *client = arg;
 217
 218     qemu_mutex_lock(&client->mutex);
 219     nfs_service(client->context, POLLOUT);
 220     nfs_set_events(client);
 221     qemu_mutex_unlock(&client->mutex);
 222 }
 223
 224 static void coroutine_fn nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 225 {
 226     *task = (NFSRPC) {
 227         .co             = qemu_coroutine_self(),
 228         .bs             = bs,
 229         .client         = bs->opaque,
 230     };
 231 }
 232
 233 static void nfs_co_generic_bh_cb(void *opaque)
 234 {
 235     NFSRPC *task = opaque;
 236
 237     task->complete = 1;
 238     aio_co_wake(task->co);
 239 }
 240
 241 /* Called (via nfs_service) with QemuMutex held.  */
 242 static void
 243 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 244                   void *private_data)
 245 {
 246     NFSRPC *task = private_data;
 247     task->ret = ret;
 248     assert(!task->st);
 249     if (task->ret > 0 && task->iov) {
 250         if (task->ret <= task->iov->size) {
 251             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 252         } else {
 253             task->ret = -EIO;
 254         }
 255     }
 256     if (task->ret < 0) {
 257         error_report("NFS Error: %s", nfs_get_error(nfs));
 258     }
 259     replay_bh_schedule_oneshot_event(task->client->aio_context,
 260                                      nfs_co_generic_bh_cb, task);
 261 }
 262
 263 static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset,
 264                                       int64_t bytes, QEMUIOVector *iov,
 265                                       BdrvRequestFlags flags)
 266 {
 267     NFSClient *client = bs->opaque;
 268     NFSRPC task;
 269
 270     nfs_co_init_task(bs, &task);
 271     task.iov = iov;
 272
 273     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 274         if (nfs_pread_async(client->context, client->fh,
 275                             offset, bytes, nfs_co_generic_cb, &task) != 0) {
 276             return -ENOMEM;
 277         }
 278
 279         nfs_set_events(client);
 280     }
 281     while (!task.complete) {
 282         qemu_coroutine_yield();
 283     }
 284
 285     if (task.ret < 0) {
 286         return task.ret;
 287     }
 288
 289     /* zero pad short reads */
 290     if (task.ret < iov->size) {
 291         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 292     }
 293
 294     return 0;
 295 }
 296
 297 static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, int64_t offset,
 298                                        int64_t bytes, QEMUIOVector *iov,
 299                                        BdrvRequestFlags flags)
 300 {
 301     NFSClient *client = bs->opaque;
 302     NFSRPC task;
 303     char *buf = NULL;
 304     bool my_buffer = false;
 305
 306     nfs_co_init_task(bs, &task);
 307
 308     if (iov->niov != 1) {
 309         buf = g_try_malloc(bytes);
 310         if (bytes && buf == NULL) {
 311             return -ENOMEM;
 312         }
 313         qemu_iovec_to_buf(iov, 0, buf, bytes);
 314         my_buffer = true;
 315     } else {
 316         buf = iov->iov[0].iov_base;
 317     }
 318
 319     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 320         if (nfs_pwrite_async(client->context, client->fh,
 321                              offset, bytes, buf,
 322                              nfs_co_generic_cb, &task) != 0) {
 323             if (my_buffer) {
 324                 g_free(buf);
 325             }
 326             return -ENOMEM;
 327         }
 328
 329         nfs_set_events(client);
 330     }
 331     while (!task.complete) {
 332         qemu_coroutine_yield();
 333     }
 334
 335     if (my_buffer) {
 336         g_free(buf);
 337     }
 338
 339     if (task.ret != bytes) {
 340         return task.ret < 0 ? task.ret : -EIO;
 341     }
 342
 343     return 0;
 344 }
 345
 346 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 347 {
 348     NFSClient *client = bs->opaque;
 349     NFSRPC task;
 350
 351     nfs_co_init_task(bs, &task);
 352
 353     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 354         if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 355                             &task) != 0) {
 356             return -ENOMEM;
 357         }
 358
 359         nfs_set_events(client);
 360     }
 361     while (!task.complete) {
 362         qemu_coroutine_yield();
 363     }
 364
 365     return task.ret;
 366 }
 367
 368 static void nfs_detach_aio_context(BlockDriverState *bs)
 369 {
 370     NFSClient *client = bs->opaque;
 371
 372     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 373                        NULL, NULL, NULL, NULL, NULL);
 374     client->events = 0;
 375 }
 376
 377 static void nfs_attach_aio_context(BlockDriverState *bs,
 378                                    AioContext *new_context)
 379 {
 380     NFSClient *client = bs->opaque;
 381
 382     client->aio_context = new_context;
 383     nfs_set_events(client);
 384 }
 385
 386 static void nfs_client_close(NFSClient *client)
 387 {
 388     if (client->context) {
 389         qemu_mutex_lock(&client->mutex);
 390         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 391                            NULL, NULL, NULL, NULL, NULL);
 392         qemu_mutex_unlock(&client->mutex);
 393         if (client->fh) {
 394             nfs_close(client->context, client->fh);
 395             client->fh = NULL;
 396         }
 397 #ifdef LIBNFS_FEATURE_UMOUNT
 398         nfs_umount(client->context);
 399 #endif
 400         nfs_destroy_context(client->context);
 401         client->context = NULL;
 402     }
 403     g_free(client->path);
 404     qemu_mutex_destroy(&client->mutex);
 405     qapi_free_NFSServer(client->server);
 406     client->server = NULL;
 407 }
 408
 409 static void nfs_file_close(BlockDriverState *bs)
 410 {
 411     NFSClient *client = bs->opaque;
 412     nfs_client_close(client);
 413 }
 414
 415 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 416                                int flags, int open_flags, Error **errp)
 417 {
 418     int64_t ret = -EINVAL;
 419 #ifdef _WIN32
 420     struct __stat64 st;
 421 #else
 422     struct stat st;
 423 #endif
 424     char *file = NULL, *strp = NULL;
 425
 426     qemu_mutex_init(&client->mutex);
 427
 428     client->path = g_strdup(opts->path);
 429
 430     strp = strrchr(client->path, '/');
 431     if (strp == NULL) {
 432         error_setg(errp, "Invalid URL specified");
 433         goto fail;
 434     }
 435     file = g_strdup(strp);
 436     *strp = 0;
 437
 438     /* Steal the NFSServer object from opts; set the original pointer to NULL
 439      * to avoid use after free and double free. */
 440     client->server = opts->server;
 441     opts->server = NULL;
 442
 443     client->context = nfs_init_context();
 444     if (client->context == NULL) {
 445         error_setg(errp, "Failed to init NFS context");
 446         goto fail;
 447     }
 448
 449     if (opts->has_user) {
 450         client->uid = opts->user;
 451         nfs_set_uid(client->context, client->uid);
 452     }
 453
 454     if (opts->has_group) {
 455         client->gid = opts->group;
 456         nfs_set_gid(client->context, client->gid);
 457     }
 458
 459     if (opts->has_tcp_syn_count) {
 460         client->tcp_syncnt = opts->tcp_syn_count;
 461         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 462     }
 463
 464 #ifdef LIBNFS_FEATURE_READAHEAD
 465     if (opts->has_readahead_size) {
 466         if (open_flags & BDRV_O_NOCACHE) {
 467             error_setg(errp, "Cannot enable NFS readahead "
 468                              "if cache.direct = on");
 469             goto fail;
 470         }
 471         client->readahead = opts->readahead_size;
 472         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 473             warn_report("Truncating NFS readahead size to %d",
 474                         QEMU_NFS_MAX_READAHEAD_SIZE);
 475             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 476         }
 477         nfs_set_readahead(client->context, client->readahead);
 478 #ifdef LIBNFS_FEATURE_PAGECACHE
 479         nfs_set_pagecache_ttl(client->context, 0);
 480 #endif
 481         client->cache_used = true;
 482     }
 483 #endif
 484
 485 #ifdef LIBNFS_FEATURE_PAGECACHE
 486     if (opts->has_page_cache_size) {
 487         if (open_flags & BDRV_O_NOCACHE) {
 488             error_setg(errp, "Cannot enable NFS pagecache "
 489                              "if cache.direct = on");
 490             goto fail;
 491         }
 492         client->pagecache = opts->page_cache_size;
 493         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 494             warn_report("Truncating NFS pagecache size to %d pages",
 495                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 496             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 497         }
 498         nfs_set_pagecache(client->context, client->pagecache);
 499         nfs_set_pagecache_ttl(client->context, 0);
 500         client->cache_used = true;
 501     }
 502 #endif
 503
 504 #ifdef LIBNFS_FEATURE_DEBUG
 505     if (opts->has_debug) {
 506         client->debug = opts->debug;
 507         /* limit the maximum debug level to avoid potential flooding
 508          * of our log files. */
 509         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 510             warn_report("Limiting NFS debug level to %d",
 511                         QEMU_NFS_MAX_DEBUG_LEVEL);
 512             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 513         }
 514         nfs_set_debug(client->context, client->debug);
 515     }
 516 #endif
 517
 518     ret = nfs_mount(client->context, client->server->host, client->path);
 519     if (ret < 0) {
 520         error_setg(errp, "Failed to mount nfs share: %s",
 521                    nfs_get_error(client->context));
 522         goto fail;
 523     }
 524
 525     if (flags & O_CREAT) {
 526         ret = nfs_creat(client->context, file, 0600, &client->fh);
 527         if (ret < 0) {
 528             error_setg(errp, "Failed to create file: %s",
 529                        nfs_get_error(client->context));
 530             goto fail;
 531         }
 532     } else {
 533         ret = nfs_open(client->context, file, flags, &client->fh);
 534         if (ret < 0) {
 535             error_setg(errp, "Failed to open file : %s",
 536                        nfs_get_error(client->context));
 537             goto fail;
 538         }
 539     }
 540
 541     ret = nfs_fstat(client->context, client->fh, &st);
 542     if (ret < 0) {
 543         error_setg(errp, "Failed to fstat file: %s",
 544                    nfs_get_error(client->context));
 545         goto fail;
 546     }
 547
 548     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 549 #if !defined(_WIN32)
 550     client->st_blocks = st.st_blocks;
 551 #endif
 552     client->has_zero_init = S_ISREG(st.st_mode);
 553     *strp = '/';
 554     goto out;
 555
 556 fail:
 557     nfs_client_close(client);
 558 out:
 559     g_free(file);
 560     return ret;
 561 }
 562
 563 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 564                                                      Error **errp)
 565 {
 566     BlockdevOptionsNfs *opts = NULL;
 567     Visitor *v;
 568     const QDictEntry *e;
 569
 570     v = qobject_input_visitor_new_flat_confused(options, errp);
 571     if (!v) {
 572         return NULL;
 573     }
 574
 575     visit_type_BlockdevOptionsNfs(v, NULL, &opts, errp);
 576     visit_free(v);
 577     if (!opts) {
 578         return NULL;
 579     }
 580
 581     /* Remove the processed options from the QDict (the visitor processes
 582      * _all_ options in the QDict) */
 583     while ((e = qdict_first(options))) {
 584         qdict_del(options, e->key);
 585     }
 586
 587     return opts;
 588 }
 589
 590 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 591                                      int flags, int open_flags, Error **errp)
 592 {
 593     BlockdevOptionsNfs *opts;
 594     int64_t ret;
 595
 596     opts = nfs_options_qdict_to_qapi(options, errp);
 597     if (opts == NULL) {
 598         ret = -EINVAL;
 599         goto fail;
 600     }
 601
 602     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 603 fail:
 604     qapi_free_BlockdevOptionsNfs(opts);
 605     return ret;
 606 }
 607
 608 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 609                          Error **errp) {
 610     NFSClient *client = bs->opaque;
 611     int64_t ret;
 612
 613     client->aio_context = bdrv_get_aio_context(bs);
 614
 615     ret = nfs_client_open_qdict(client, options,
 616                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 617                                 bs->open_flags, errp);
 618     if (ret < 0) {
 619         return ret;
 620     }
 621
 622     bs->total_sectors = ret;
 623     if (client->has_zero_init) {
 624         bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 625     }
 626     return 0;
 627 }
 628
 629 static QemuOptsList nfs_create_opts = {
 630     .name = "nfs-create-opts",
 631     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 632     .desc = {
 633         {
 634             .name = BLOCK_OPT_SIZE,
 635             .type = QEMU_OPT_SIZE,
 636             .help = "Virtual disk size"
 637         },
 638         { /* end of list */ }
 639     }
 640 };
 641
 642 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 643 {
 644     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 645     NFSClient *client = g_new0(NFSClient, 1);
 646     int ret;
 647
 648     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 649
 650     client->aio_context = qemu_get_aio_context();
 651
 652     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 653     if (ret < 0) {
 654         goto out;
 655     }
 656     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 657     nfs_client_close(client);
 658
 659 out:
 660     g_free(client);
 661     return ret;
 662 }
 663
 664 static int coroutine_fn nfs_file_co_create_opts(BlockDriver *drv,
 665                                                 const char *url,
 666                                                 QemuOpts *opts,
 667                                                 Error **errp)
 668 {
 669     BlockdevCreateOptions *create_options;
 670     BlockdevCreateOptionsNfs *nfs_opts;
 671     QDict *options;
 672     int ret;
 673
 674     create_options = g_new0(BlockdevCreateOptions, 1);
 675     create_options->driver = BLOCKDEV_DRIVER_NFS;
 676     nfs_opts = &create_options->u.nfs;
 677
 678     /* Read out options */
 679     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 680                               BDRV_SECTOR_SIZE);
 681
 682     options = qdict_new();
 683     ret = nfs_parse_uri(url, options, errp);
 684     if (ret < 0) {
 685         goto out;
 686     }
 687
 688     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 689     if (nfs_opts->location == NULL) {
 690         ret = -EINVAL;
 691         goto out;
 692     }
 693
 694     ret = nfs_file_co_create(create_options, errp);
 695     if (ret < 0) {
 696         goto out;
 697     }
 698
 699     ret = 0;
 700 out:
 701     qobject_unref(options);
 702     qapi_free_BlockdevCreateOptions(create_options);
 703     return ret;
 704 }
 705
 706 static int nfs_has_zero_init(BlockDriverState *bs)
 707 {
 708     NFSClient *client = bs->opaque;
 709     return client->has_zero_init;
 710 }
 711
 712 #if !defined(_WIN32)
 713 /* Called (via nfs_service) with QemuMutex held.  */
 714 static void
 715 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 716                                void *private_data)
 717 {
 718     NFSRPC *task = private_data;
 719     task->ret = ret;
 720     if (task->ret == 0) {
 721         memcpy(task->st, data, sizeof(struct stat));
 722     }
 723     if (task->ret < 0) {
 724         error_report("NFS Error: %s", nfs_get_error(nfs));
 725     }
 726     replay_bh_schedule_oneshot_event(task->client->aio_context,
 727                                      nfs_co_generic_bh_cb, task);
 728 }
 729
 730 static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs)
 731 {
 732     NFSClient *client = bs->opaque;
 733     NFSRPC task = {0};
 734     struct stat st;
 735
 736     if (bdrv_is_read_only(bs) &&
 737         !(bs->open_flags & BDRV_O_NOCACHE)) {
 738         return client->st_blocks * 512;
 739     }
 740
 741     nfs_co_init_task(bs, &task);
 742     task.st = &st;
 743     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 744         if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 745                             &task) != 0) {
 746             return -ENOMEM;
 747         }
 748
 749         nfs_set_events(client);
 750     }
 751     while (!task.complete) {
 752         qemu_coroutine_yield();
 753     }
 754
 755     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 756 }
 757 #endif
 758
 759 static int coroutine_fn
 760 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 761                      PreallocMode prealloc, BdrvRequestFlags flags,
 762                      Error **errp)
 763 {
 764     NFSClient *client = bs->opaque;
 765     int ret;
 766
 767     if (prealloc != PREALLOC_MODE_OFF) {
 768         error_setg(errp, "Unsupported preallocation mode '%s'",
 769                    PreallocMode_str(prealloc));
 770         return -ENOTSUP;
 771     }
 772
 773     ret = nfs_ftruncate(client->context, client->fh, offset);
 774     if (ret < 0) {
 775         error_setg_errno(errp, -ret, "Failed to truncate file");
 776         return ret;
 777     }
 778
 779     return 0;
 780 }
 781
 782 /* Note that this will not re-establish a connection with the NFS server
 783  * - it is effectively a NOP.  */
 784 static int nfs_reopen_prepare(BDRVReopenState *state,
 785                               BlockReopenQueue *queue, Error **errp)
 786 {
 787     NFSClient *client = state->bs->opaque;
 788 #ifdef _WIN32
 789     struct __stat64 st;
 790 #else
 791     struct stat st;
 792 #endif
 793     int ret = 0;
 794
 795     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 796         error_setg(errp, "Cannot open a read-only mount as read-write");
 797         return -EACCES;
 798     }
 799
 800     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 801         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 802                          " pagecache is enabled");
 803         return -EINVAL;
 804     }
 805
 806     /* Update cache for read-only reopens */
 807     if (!(state->flags & BDRV_O_RDWR)) {
 808         ret = nfs_fstat(client->context, client->fh, &st);
 809         if (ret < 0) {
 810             error_setg(errp, "Failed to fstat file: %s",
 811                        nfs_get_error(client->context));
 812             return ret;
 813         }
 814 #if !defined(_WIN32)
 815         client->st_blocks = st.st_blocks;
 816 #endif
 817     }
 818
 819     return 0;
 820 }
 821
 822 static void nfs_refresh_filename(BlockDriverState *bs)
 823 {
 824     NFSClient *client = bs->opaque;
 825
 826     if (client->uid && !client->gid) {
 827         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 828                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 829                  client->uid);
 830     } else if (!client->uid && client->gid) {
 831         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 832                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 833                  client->gid);
 834     } else if (client->uid && client->gid) {
 835         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 836                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 837                  client->server->host, client->path, client->uid, client->gid);
 838     } else {
 839         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 840                  "nfs://%s%s", client->server->host, client->path);
 841     }
 842 }
 843
 844 static char * GRAPH_RDLOCK nfs_dirname(BlockDriverState *bs, Error **errp)
 845 {
 846     NFSClient *client = bs->opaque;
 847
 848     if (client->uid || client->gid) {
 849         bdrv_refresh_filename(bs);
 850         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 851                    bs->filename);
 852         return NULL;
 853     }
 854
 855     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 856 }
 857
 858 #ifdef LIBNFS_FEATURE_PAGECACHE
 859 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 860                                                  Error **errp)
 861 {
 862     NFSClient *client = bs->opaque;
 863     nfs_pagecache_invalidate(client->context, client->fh);
 864 }
 865 #endif
 866
 867 static const char *nfs_strong_runtime_opts[] = {
 868     "path",
 869     "user",
 870     "group",
 871     "server.",
 872
 873     NULL
 874 };
 875
 876 static BlockDriver bdrv_nfs = {
 877     .format_name                    = "nfs",
 878     .protocol_name                  = "nfs",
 879
 880     .instance_size                  = sizeof(NFSClient),
 881     .bdrv_parse_filename            = nfs_parse_filename,
 882     .create_opts                    = &nfs_create_opts,
 883
 884     .bdrv_has_zero_init             = nfs_has_zero_init,
 885 /* libnfs does not provide the allocated filesize of a file on win32. */
 886 #if !defined(_WIN32)
 887     .bdrv_co_get_allocated_file_size = nfs_co_get_allocated_file_size,
 888 #endif
 889     .bdrv_co_truncate               = nfs_file_co_truncate,
 890
 891     .bdrv_open                      = nfs_file_open,
 892     .bdrv_close                     = nfs_file_close,
 893     .bdrv_co_create                 = nfs_file_co_create,
 894     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 895     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 896
 897     .bdrv_co_preadv                 = nfs_co_preadv,
 898     .bdrv_co_pwritev                = nfs_co_pwritev,
 899     .bdrv_co_flush_to_disk          = nfs_co_flush,
 900
 901     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 902     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 903     .bdrv_refresh_filename          = nfs_refresh_filename,
 904     .bdrv_dirname                   = nfs_dirname,
 905
 906     .strong_runtime_opts            = nfs_strong_runtime_opts,
 907
 908 #ifdef LIBNFS_FEATURE_PAGECACHE
 909     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 910 #endif
 911 };
 912
 913 static void nfs_block_init(void)
 914 {
 915     bdrv_register(&bdrv_nfs);
 916 }
 917
 918 block_init(nfs_block_init);