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_int.h"
  34 #include "block/qdict.h"
  35 #include "trace.h"
  36 #include "qemu/iov.h"
  37 #include "qemu/main-loop.h"
  38 #include "qemu/module.h"
  39 #include "qemu/option.h"
  40 #include "qemu/uri.h"
  41 #include "qemu/cutils.h"
  42 #include "sysemu/sysemu.h"
  43 #include "sysemu/replay.h"
  44 #include "qapi/qapi-visit-block-core.h"
  45 #include "qapi/qmp/qdict.h"
  46 #include "qapi/qmp/qstring.h"
  47 #include "qapi/qobject-input-visitor.h"
  48 #include "qapi/qobject-output-visitor.h"
  49 #include <nfsc/libnfs.h>
  50
  51
  52 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  53 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  54 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  55
  56 typedef struct NFSClient {
  57     struct nfs_context *context;
  58     struct nfsfh *fh;
  59     int events;
  60     bool has_zero_init;
  61     AioContext *aio_context;
  62     QemuMutex mutex;
  63     uint64_t st_blocks;
  64     bool cache_used;
  65     NFSServer *server;
  66     char *path;
  67     int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug;
  68 } NFSClient;
  69
  70 typedef struct NFSRPC {
  71     BlockDriverState *bs;
  72     int ret;
  73     int complete;
  74     QEMUIOVector *iov;
  75     struct stat *st;
  76     Coroutine *co;
  77     NFSClient *client;
  78 } NFSRPC;
  79
  80 static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
  81 {
  82     URI *uri = NULL;
  83     QueryParams *qp = NULL;
  84     int ret = -EINVAL, i;
  85
  86     uri = uri_parse(filename);
  87     if (!uri) {
  88         error_setg(errp, "Invalid URI specified");
  89         goto out;
  90     }
  91     if (g_strcmp0(uri->scheme, "nfs") != 0) {
  92         error_setg(errp, "URI scheme must be 'nfs'");
  93         goto out;
  94     }
  95
  96     if (!uri->server) {
  97         error_setg(errp, "missing hostname in URI");
  98         goto out;
  99     }
 100
 101     if (!uri->path) {
 102         error_setg(errp, "missing file path in URI");
 103         goto out;
 104     }
 105
 106     qp = query_params_parse(uri->query);
 107     if (!qp) {
 108         error_setg(errp, "could not parse query parameters");
 109         goto out;
 110     }
 111
 112     qdict_put_str(options, "server.host", uri->server);
 113     qdict_put_str(options, "server.type", "inet");
 114     qdict_put_str(options, "path", uri->path);
 115
 116     for (i = 0; i < qp->n; i++) {
 117         unsigned long long val;
 118         if (!qp->p[i].value) {
 119             error_setg(errp, "Value for NFS parameter expected: %s",
 120                        qp->p[i].name);
 121             goto out;
 122         }
 123         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 124             error_setg(errp, "Illegal value for NFS parameter: %s",
 125                        qp->p[i].name);
 126             goto out;
 127         }
 128         if (!strcmp(qp->p[i].name, "uid")) {
 129             qdict_put_str(options, "user", qp->p[i].value);
 130         } else if (!strcmp(qp->p[i].name, "gid")) {
 131             qdict_put_str(options, "group", qp->p[i].value);
 132         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 133             qdict_put_str(options, "tcp-syn-count", qp->p[i].value);
 134         } else if (!strcmp(qp->p[i].name, "readahead")) {
 135             qdict_put_str(options, "readahead-size", qp->p[i].value);
 136         } else if (!strcmp(qp->p[i].name, "pagecache")) {
 137             qdict_put_str(options, "page-cache-size", qp->p[i].value);
 138         } else if (!strcmp(qp->p[i].name, "debug")) {
 139             qdict_put_str(options, "debug", qp->p[i].value);
 140         } else {
 141             error_setg(errp, "Unknown NFS parameter name: %s",
 142                        qp->p[i].name);
 143             goto out;
 144         }
 145     }
 146     ret = 0;
 147 out:
 148     if (qp) {
 149         query_params_free(qp);
 150     }
 151     if (uri) {
 152         uri_free(uri);
 153     }
 154     return ret;
 155 }
 156
 157 static bool nfs_has_filename_options_conflict(QDict *options, Error **errp)
 158 {
 159     const QDictEntry *qe;
 160
 161     for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
 162         if (!strcmp(qe->key, "host") ||
 163             !strcmp(qe->key, "path") ||
 164             !strcmp(qe->key, "user") ||
 165             !strcmp(qe->key, "group") ||
 166             !strcmp(qe->key, "tcp-syn-count") ||
 167             !strcmp(qe->key, "readahead-size") ||
 168             !strcmp(qe->key, "page-cache-size") ||
 169             !strcmp(qe->key, "debug") ||
 170             strstart(qe->key, "server.", NULL))
 171         {
 172             error_setg(errp, "Option %s cannot be used with a filename",
 173                        qe->key);
 174             return true;
 175         }
 176     }
 177
 178     return false;
 179 }
 180
 181 static void nfs_parse_filename(const char *filename, QDict *options,
 182                                Error **errp)
 183 {
 184     if (nfs_has_filename_options_conflict(options, errp)) {
 185         return;
 186     }
 187
 188     nfs_parse_uri(filename, options, errp);
 189 }
 190
 191 static void nfs_process_read(void *arg);
 192 static void nfs_process_write(void *arg);
 193
 194 /* Called with QemuMutex held.  */
 195 static void nfs_set_events(NFSClient *client)
 196 {
 197     int ev = nfs_which_events(client->context);
 198     if (ev != client->events) {
 199         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 200                            false,
 201                            (ev & POLLIN) ? nfs_process_read : NULL,
 202                            (ev & POLLOUT) ? nfs_process_write : NULL,
 203                            NULL, client);
 204
 205     }
 206     client->events = ev;
 207 }
 208
 209 static void nfs_process_read(void *arg)
 210 {
 211     NFSClient *client = arg;
 212
 213     qemu_mutex_lock(&client->mutex);
 214     nfs_service(client->context, POLLIN);
 215     nfs_set_events(client);
 216     qemu_mutex_unlock(&client->mutex);
 217 }
 218
 219 static void nfs_process_write(void *arg)
 220 {
 221     NFSClient *client = arg;
 222
 223     qemu_mutex_lock(&client->mutex);
 224     nfs_service(client->context, POLLOUT);
 225     nfs_set_events(client);
 226     qemu_mutex_unlock(&client->mutex);
 227 }
 228
 229 static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 230 {
 231     *task = (NFSRPC) {
 232         .co             = qemu_coroutine_self(),
 233         .bs             = bs,
 234         .client         = bs->opaque,
 235     };
 236 }
 237
 238 static void nfs_co_generic_bh_cb(void *opaque)
 239 {
 240     NFSRPC *task = opaque;
 241
 242     task->complete = 1;
 243     aio_co_wake(task->co);
 244 }
 245
 246 /* Called (via nfs_service) with QemuMutex held.  */
 247 static void
 248 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 249                   void *private_data)
 250 {
 251     NFSRPC *task = private_data;
 252     task->ret = ret;
 253     assert(!task->st);
 254     if (task->ret > 0 && task->iov) {
 255         if (task->ret <= task->iov->size) {
 256             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 257         } else {
 258             task->ret = -EIO;
 259         }
 260     }
 261     if (task->ret < 0) {
 262         error_report("NFS Error: %s", nfs_get_error(nfs));
 263     }
 264     replay_bh_schedule_oneshot_event(task->client->aio_context,
 265                                      nfs_co_generic_bh_cb, task);
 266 }
 267
 268 static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, uint64_t offset,
 269                                       uint64_t bytes, QEMUIOVector *iov,
 270                                       int flags)
 271 {
 272     NFSClient *client = bs->opaque;
 273     NFSRPC task;
 274
 275     nfs_co_init_task(bs, &task);
 276     task.iov = iov;
 277
 278     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 279         if (nfs_pread_async(client->context, client->fh,
 280                             offset, bytes, nfs_co_generic_cb, &task) != 0) {
 281             return -ENOMEM;
 282         }
 283
 284         nfs_set_events(client);
 285     }
 286     while (!task.complete) {
 287         qemu_coroutine_yield();
 288     }
 289
 290     if (task.ret < 0) {
 291         return task.ret;
 292     }
 293
 294     /* zero pad short reads */
 295     if (task.ret < iov->size) {
 296         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 297     }
 298
 299     return 0;
 300 }
 301
 302 static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset,
 303                                        uint64_t bytes, QEMUIOVector *iov,
 304                                        int flags)
 305 {
 306     NFSClient *client = bs->opaque;
 307     NFSRPC task;
 308     char *buf = NULL;
 309     bool my_buffer = false;
 310
 311     nfs_co_init_task(bs, &task);
 312
 313     if (iov->niov != 1) {
 314         buf = g_try_malloc(bytes);
 315         if (bytes && buf == NULL) {
 316             return -ENOMEM;
 317         }
 318         qemu_iovec_to_buf(iov, 0, buf, bytes);
 319         my_buffer = true;
 320     } else {
 321         buf = iov->iov[0].iov_base;
 322     }
 323
 324     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 325         if (nfs_pwrite_async(client->context, client->fh,
 326                              offset, bytes, buf,
 327                              nfs_co_generic_cb, &task) != 0) {
 328             if (my_buffer) {
 329                 g_free(buf);
 330             }
 331             return -ENOMEM;
 332         }
 333
 334         nfs_set_events(client);
 335     }
 336     while (!task.complete) {
 337         qemu_coroutine_yield();
 338     }
 339
 340     if (my_buffer) {
 341         g_free(buf);
 342     }
 343
 344     if (task.ret != bytes) {
 345         return task.ret < 0 ? task.ret : -EIO;
 346     }
 347
 348     return 0;
 349 }
 350
 351 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 352 {
 353     NFSClient *client = bs->opaque;
 354     NFSRPC task;
 355
 356     nfs_co_init_task(bs, &task);
 357
 358     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 359         if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 360                             &task) != 0) {
 361             return -ENOMEM;
 362         }
 363
 364         nfs_set_events(client);
 365     }
 366     while (!task.complete) {
 367         qemu_coroutine_yield();
 368     }
 369
 370     return task.ret;
 371 }
 372
 373 static void nfs_detach_aio_context(BlockDriverState *bs)
 374 {
 375     NFSClient *client = bs->opaque;
 376
 377     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 378                        false, NULL, NULL, NULL, NULL);
 379     client->events = 0;
 380 }
 381
 382 static void nfs_attach_aio_context(BlockDriverState *bs,
 383                                    AioContext *new_context)
 384 {
 385     NFSClient *client = bs->opaque;
 386
 387     client->aio_context = new_context;
 388     nfs_set_events(client);
 389 }
 390
 391 static void nfs_client_close(NFSClient *client)
 392 {
 393     if (client->context) {
 394         qemu_mutex_lock(&client->mutex);
 395         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 396                            false, NULL, NULL, NULL, NULL);
 397         qemu_mutex_unlock(&client->mutex);
 398         if (client->fh) {
 399             nfs_close(client->context, client->fh);
 400             client->fh = NULL;
 401         }
 402 #ifdef LIBNFS_FEATURE_UMOUNT
 403         nfs_umount(client->context);
 404 #endif
 405         nfs_destroy_context(client->context);
 406         client->context = NULL;
 407     }
 408     g_free(client->path);
 409     qemu_mutex_destroy(&client->mutex);
 410     qapi_free_NFSServer(client->server);
 411     client->server = NULL;
 412 }
 413
 414 static void nfs_file_close(BlockDriverState *bs)
 415 {
 416     NFSClient *client = bs->opaque;
 417     nfs_client_close(client);
 418 }
 419
 420 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 421                                int flags, int open_flags, Error **errp)
 422 {
 423     int64_t ret = -EINVAL;
 424     struct stat st;
 425     char *file = NULL, *strp = NULL;
 426
 427     qemu_mutex_init(&client->mutex);
 428
 429     client->path = g_strdup(opts->path);
 430
 431     strp = strrchr(client->path, '/');
 432     if (strp == NULL) {
 433         error_setg(errp, "Invalid URL specified");
 434         goto fail;
 435     }
 436     file = g_strdup(strp);
 437     *strp = 0;
 438
 439     /* Steal the NFSServer object from opts; set the original pointer to NULL
 440      * to avoid use after free and double free. */
 441     client->server = opts->server;
 442     opts->server = NULL;
 443
 444     client->context = nfs_init_context();
 445     if (client->context == NULL) {
 446         error_setg(errp, "Failed to init NFS context");
 447         goto fail;
 448     }
 449
 450     if (opts->has_user) {
 451         client->uid = opts->user;
 452         nfs_set_uid(client->context, client->uid);
 453     }
 454
 455     if (opts->has_group) {
 456         client->gid = opts->group;
 457         nfs_set_gid(client->context, client->gid);
 458     }
 459
 460     if (opts->has_tcp_syn_count) {
 461         client->tcp_syncnt = opts->tcp_syn_count;
 462         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 463     }
 464
 465 #ifdef LIBNFS_FEATURE_READAHEAD
 466     if (opts->has_readahead_size) {
 467         if (open_flags & BDRV_O_NOCACHE) {
 468             error_setg(errp, "Cannot enable NFS readahead "
 469                              "if cache.direct = on");
 470             goto fail;
 471         }
 472         client->readahead = opts->readahead_size;
 473         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 474             warn_report("Truncating NFS readahead size to %d",
 475                         QEMU_NFS_MAX_READAHEAD_SIZE);
 476             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 477         }
 478         nfs_set_readahead(client->context, client->readahead);
 479 #ifdef LIBNFS_FEATURE_PAGECACHE
 480         nfs_set_pagecache_ttl(client->context, 0);
 481 #endif
 482         client->cache_used = true;
 483     }
 484 #endif
 485
 486 #ifdef LIBNFS_FEATURE_PAGECACHE
 487     if (opts->has_page_cache_size) {
 488         if (open_flags & BDRV_O_NOCACHE) {
 489             error_setg(errp, "Cannot enable NFS pagecache "
 490                              "if cache.direct = on");
 491             goto fail;
 492         }
 493         client->pagecache = opts->page_cache_size;
 494         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 495             warn_report("Truncating NFS pagecache size to %d pages",
 496                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 497             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 498         }
 499         nfs_set_pagecache(client->context, client->pagecache);
 500         nfs_set_pagecache_ttl(client->context, 0);
 501         client->cache_used = true;
 502     }
 503 #endif
 504
 505 #ifdef LIBNFS_FEATURE_DEBUG
 506     if (opts->has_debug) {
 507         client->debug = opts->debug;
 508         /* limit the maximum debug level to avoid potential flooding
 509          * of our log files. */
 510         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 511             warn_report("Limiting NFS debug level to %d",
 512                         QEMU_NFS_MAX_DEBUG_LEVEL);
 513             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 514         }
 515         nfs_set_debug(client->context, client->debug);
 516     }
 517 #endif
 518
 519     ret = nfs_mount(client->context, client->server->host, client->path);
 520     if (ret < 0) {
 521         error_setg(errp, "Failed to mount nfs share: %s",
 522                    nfs_get_error(client->context));
 523         goto fail;
 524     }
 525
 526     if (flags & O_CREAT) {
 527         ret = nfs_creat(client->context, file, 0600, &client->fh);
 528         if (ret < 0) {
 529             error_setg(errp, "Failed to create file: %s",
 530                        nfs_get_error(client->context));
 531             goto fail;
 532         }
 533     } else {
 534         ret = nfs_open(client->context, file, flags, &client->fh);
 535         if (ret < 0) {
 536             error_setg(errp, "Failed to open file : %s",
 537                        nfs_get_error(client->context));
 538             goto fail;
 539         }
 540     }
 541
 542     ret = nfs_fstat(client->context, client->fh, &st);
 543     if (ret < 0) {
 544         error_setg(errp, "Failed to fstat file: %s",
 545                    nfs_get_error(client->context));
 546         goto fail;
 547     }
 548
 549     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 550 #if !defined(_WIN32)
 551     client->st_blocks = st.st_blocks;
 552 #endif
 553     client->has_zero_init = S_ISREG(st.st_mode);
 554     *strp = '/';
 555     goto out;
 556
 557 fail:
 558     nfs_client_close(client);
 559 out:
 560     g_free(file);
 561     return ret;
 562 }
 563
 564 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 565                                                      Error **errp)
 566 {
 567     BlockdevOptionsNfs *opts = NULL;
 568     Visitor *v;
 569     const QDictEntry *e;
 570
 571     v = qobject_input_visitor_new_flat_confused(options, errp);
 572     if (!v) {
 573         return NULL;
 574     }
 575
 576     visit_type_BlockdevOptionsNfs(v, NULL, &opts, errp);
 577     visit_free(v);
 578     if (!opts) {
 579         return NULL;
 580     }
 581
 582     /* Remove the processed options from the QDict (the visitor processes
 583      * _all_ options in the QDict) */
 584     while ((e = qdict_first(options))) {
 585         qdict_del(options, e->key);
 586     }
 587
 588     return opts;
 589 }
 590
 591 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 592                                      int flags, int open_flags, Error **errp)
 593 {
 594     BlockdevOptionsNfs *opts;
 595     int64_t ret;
 596
 597     opts = nfs_options_qdict_to_qapi(options, errp);
 598     if (opts == NULL) {
 599         ret = -EINVAL;
 600         goto fail;
 601     }
 602
 603     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 604 fail:
 605     qapi_free_BlockdevOptionsNfs(opts);
 606     return ret;
 607 }
 608
 609 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 610                          Error **errp) {
 611     NFSClient *client = bs->opaque;
 612     int64_t ret;
 613
 614     client->aio_context = bdrv_get_aio_context(bs);
 615
 616     ret = nfs_client_open_qdict(client, options,
 617                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 618                                 bs->open_flags, errp);
 619     if (ret < 0) {
 620         return ret;
 621     }
 622
 623     bs->total_sectors = ret;
 624     if (client->has_zero_init) {
 625         bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 626     }
 627     return 0;
 628 }
 629
 630 static QemuOptsList nfs_create_opts = {
 631     .name = "nfs-create-opts",
 632     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 633     .desc = {
 634         {
 635             .name = BLOCK_OPT_SIZE,
 636             .type = QEMU_OPT_SIZE,
 637             .help = "Virtual disk size"
 638         },
 639         { /* end of list */ }
 640     }
 641 };
 642
 643 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 644 {
 645     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 646     NFSClient *client = g_new0(NFSClient, 1);
 647     int ret;
 648
 649     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 650
 651     client->aio_context = qemu_get_aio_context();
 652
 653     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 654     if (ret < 0) {
 655         goto out;
 656     }
 657     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 658     nfs_client_close(client);
 659
 660 out:
 661     g_free(client);
 662     return ret;
 663 }
 664
 665 static int coroutine_fn nfs_file_co_create_opts(BlockDriver *drv,
 666                                                 const char *url,
 667                                                 QemuOpts *opts,
 668                                                 Error **errp)
 669 {
 670     BlockdevCreateOptions *create_options;
 671     BlockdevCreateOptionsNfs *nfs_opts;
 672     QDict *options;
 673     int ret;
 674
 675     create_options = g_new0(BlockdevCreateOptions, 1);
 676     create_options->driver = BLOCKDEV_DRIVER_NFS;
 677     nfs_opts = &create_options->u.nfs;
 678
 679     /* Read out options */
 680     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 681                               BDRV_SECTOR_SIZE);
 682
 683     options = qdict_new();
 684     ret = nfs_parse_uri(url, options, errp);
 685     if (ret < 0) {
 686         goto out;
 687     }
 688
 689     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 690     if (nfs_opts->location == NULL) {
 691         ret = -EINVAL;
 692         goto out;
 693     }
 694
 695     ret = nfs_file_co_create(create_options, errp);
 696     if (ret < 0) {
 697         goto out;
 698     }
 699
 700     ret = 0;
 701 out:
 702     qobject_unref(options);
 703     qapi_free_BlockdevCreateOptions(create_options);
 704     return ret;
 705 }
 706
 707 static int nfs_has_zero_init(BlockDriverState *bs)
 708 {
 709     NFSClient *client = bs->opaque;
 710     return client->has_zero_init;
 711 }
 712
 713 #if !defined(_WIN32)
 714 /* Called (via nfs_service) with QemuMutex held.  */
 715 static void
 716 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 717                                void *private_data)
 718 {
 719     NFSRPC *task = private_data;
 720     task->ret = ret;
 721     if (task->ret == 0) {
 722         memcpy(task->st, data, sizeof(struct stat));
 723     }
 724     if (task->ret < 0) {
 725         error_report("NFS Error: %s", nfs_get_error(nfs));
 726     }
 727
 728     /* Set task->complete before reading bs->wakeup.  */
 729     qatomic_mb_set(&task->complete, 1);
 730     bdrv_wakeup(task->bs);
 731 }
 732
 733 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 734 {
 735     NFSClient *client = bs->opaque;
 736     NFSRPC task = {0};
 737     struct stat st;
 738
 739     if (bdrv_is_read_only(bs) &&
 740         !(bs->open_flags & BDRV_O_NOCACHE)) {
 741         return client->st_blocks * 512;
 742     }
 743
 744     task.bs = bs;
 745     task.st = &st;
 746     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 747                         &task) != 0) {
 748         return -ENOMEM;
 749     }
 750
 751     nfs_set_events(client);
 752     BDRV_POLL_WHILE(bs, !task.complete);
 753
 754     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 755 }
 756 #endif
 757
 758 static int coroutine_fn
 759 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 760                      PreallocMode prealloc, BdrvRequestFlags flags,
 761                      Error **errp)
 762 {
 763     NFSClient *client = bs->opaque;
 764     int ret;
 765
 766     if (prealloc != PREALLOC_MODE_OFF) {
 767         error_setg(errp, "Unsupported preallocation mode '%s'",
 768                    PreallocMode_str(prealloc));
 769         return -ENOTSUP;
 770     }
 771
 772     ret = nfs_ftruncate(client->context, client->fh, offset);
 773     if (ret < 0) {
 774         error_setg_errno(errp, -ret, "Failed to truncate file");
 775         return ret;
 776     }
 777
 778     return 0;
 779 }
 780
 781 /* Note that this will not re-establish a connection with the NFS server
 782  * - it is effectively a NOP.  */
 783 static int nfs_reopen_prepare(BDRVReopenState *state,
 784                               BlockReopenQueue *queue, Error **errp)
 785 {
 786     NFSClient *client = state->bs->opaque;
 787     struct stat st;
 788     int ret = 0;
 789
 790     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 791         error_setg(errp, "Cannot open a read-only mount as read-write");
 792         return -EACCES;
 793     }
 794
 795     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 796         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 797                          " pagecache is enabled");
 798         return -EINVAL;
 799     }
 800
 801     /* Update cache for read-only reopens */
 802     if (!(state->flags & BDRV_O_RDWR)) {
 803         ret = nfs_fstat(client->context, client->fh, &st);
 804         if (ret < 0) {
 805             error_setg(errp, "Failed to fstat file: %s",
 806                        nfs_get_error(client->context));
 807             return ret;
 808         }
 809 #if !defined(_WIN32)
 810         client->st_blocks = st.st_blocks;
 811 #endif
 812     }
 813
 814     return 0;
 815 }
 816
 817 static void nfs_refresh_filename(BlockDriverState *bs)
 818 {
 819     NFSClient *client = bs->opaque;
 820
 821     if (client->uid && !client->gid) {
 822         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 823                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 824                  client->uid);
 825     } else if (!client->uid && client->gid) {
 826         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 827                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 828                  client->gid);
 829     } else if (client->uid && client->gid) {
 830         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 831                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 832                  client->server->host, client->path, client->uid, client->gid);
 833     } else {
 834         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 835                  "nfs://%s%s", client->server->host, client->path);
 836     }
 837 }
 838
 839 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 840 {
 841     NFSClient *client = bs->opaque;
 842
 843     if (client->uid || client->gid) {
 844         bdrv_refresh_filename(bs);
 845         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 846                    bs->filename);
 847         return NULL;
 848     }
 849
 850     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 851 }
 852
 853 #ifdef LIBNFS_FEATURE_PAGECACHE
 854 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 855                                                  Error **errp)
 856 {
 857     NFSClient *client = bs->opaque;
 858     nfs_pagecache_invalidate(client->context, client->fh);
 859 }
 860 #endif
 861
 862 static const char *nfs_strong_runtime_opts[] = {
 863     "path",
 864     "user",
 865     "group",
 866     "server.",
 867
 868     NULL
 869 };
 870
 871 static BlockDriver bdrv_nfs = {
 872     .format_name                    = "nfs",
 873     .protocol_name                  = "nfs",
 874
 875     .instance_size                  = sizeof(NFSClient),
 876     .bdrv_parse_filename            = nfs_parse_filename,
 877     .create_opts                    = &nfs_create_opts,
 878
 879     .bdrv_has_zero_init             = nfs_has_zero_init,
 880 /* libnfs does not provide the allocated filesize of a file on win32. */
 881 #if !defined(_WIN32)
 882     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 883 #endif
 884     .bdrv_co_truncate               = nfs_file_co_truncate,
 885
 886     .bdrv_file_open                 = nfs_file_open,
 887     .bdrv_close                     = nfs_file_close,
 888     .bdrv_co_create                 = nfs_file_co_create,
 889     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 890     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 891
 892     .bdrv_co_preadv                 = nfs_co_preadv,
 893     .bdrv_co_pwritev                = nfs_co_pwritev,
 894     .bdrv_co_flush_to_disk          = nfs_co_flush,
 895
 896     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 897     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 898     .bdrv_refresh_filename          = nfs_refresh_filename,
 899     .bdrv_dirname                   = nfs_dirname,
 900
 901     .strong_runtime_opts            = nfs_strong_runtime_opts,
 902
 903 #ifdef LIBNFS_FEATURE_PAGECACHE
 904     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 905 #endif
 906 };
 907
 908 static void nfs_block_init(void)
 909 {
 910     bdrv_register(&bdrv_nfs);
 911 }
 912
 913 block_init(nfs_block_init);