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