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/uri.h"
  42 #include "qemu/cutils.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     uri_free(uri);
 152     return ret;
 153 }
 154
 155 static bool nfs_has_filename_options_conflict(QDict *options, Error **errp)
 156 {
 157     const QDictEntry *qe;
 158
 159     for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
 160         if (!strcmp(qe->key, "host") ||
 161             !strcmp(qe->key, "path") ||
 162             !strcmp(qe->key, "user") ||
 163             !strcmp(qe->key, "group") ||
 164             !strcmp(qe->key, "tcp-syn-count") ||
 165             !strcmp(qe->key, "readahead-size") ||
 166             !strcmp(qe->key, "page-cache-size") ||
 167             !strcmp(qe->key, "debug") ||
 168             strstart(qe->key, "server.", NULL))
 169         {
 170             error_setg(errp, "Option %s cannot be used with a filename",
 171                        qe->key);
 172             return true;
 173         }
 174     }
 175
 176     return false;
 177 }
 178
 179 static void nfs_parse_filename(const char *filename, QDict *options,
 180                                Error **errp)
 181 {
 182     if (nfs_has_filename_options_conflict(options, errp)) {
 183         return;
 184     }
 185
 186     nfs_parse_uri(filename, options, errp);
 187 }
 188
 189 static void nfs_process_read(void *arg);
 190 static void nfs_process_write(void *arg);
 191
 192 /* Called with QemuMutex held.  */
 193 static void nfs_set_events(NFSClient *client)
 194 {
 195     int ev = nfs_which_events(client->context);
 196     if (ev != client->events) {
 197         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 198                            false,
 199                            (ev & POLLIN) ? nfs_process_read : NULL,
 200                            (ev & POLLOUT) ? nfs_process_write : NULL,
 201                            NULL, NULL, client);
 202
 203     }
 204     client->events = ev;
 205 }
 206
 207 static void nfs_process_read(void *arg)
 208 {
 209     NFSClient *client = arg;
 210
 211     qemu_mutex_lock(&client->mutex);
 212     nfs_service(client->context, POLLIN);
 213     nfs_set_events(client);
 214     qemu_mutex_unlock(&client->mutex);
 215 }
 216
 217 static void nfs_process_write(void *arg)
 218 {
 219     NFSClient *client = arg;
 220
 221     qemu_mutex_lock(&client->mutex);
 222     nfs_service(client->context, POLLOUT);
 223     nfs_set_events(client);
 224     qemu_mutex_unlock(&client->mutex);
 225 }
 226
 227 static void coroutine_fn nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 228 {
 229     *task = (NFSRPC) {
 230         .co             = qemu_coroutine_self(),
 231         .bs             = bs,
 232         .client         = bs->opaque,
 233     };
 234 }
 235
 236 static void nfs_co_generic_bh_cb(void *opaque)
 237 {
 238     NFSRPC *task = opaque;
 239
 240     task->complete = 1;
 241     aio_co_wake(task->co);
 242 }
 243
 244 /* Called (via nfs_service) with QemuMutex held.  */
 245 static void
 246 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 247                   void *private_data)
 248 {
 249     NFSRPC *task = private_data;
 250     task->ret = ret;
 251     assert(!task->st);
 252     if (task->ret > 0 && task->iov) {
 253         if (task->ret <= task->iov->size) {
 254             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 255         } else {
 256             task->ret = -EIO;
 257         }
 258     }
 259     if (task->ret < 0) {
 260         error_report("NFS Error: %s", nfs_get_error(nfs));
 261     }
 262     replay_bh_schedule_oneshot_event(task->client->aio_context,
 263                                      nfs_co_generic_bh_cb, task);
 264 }
 265
 266 static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, int64_t offset,
 267                                       int64_t bytes, QEMUIOVector *iov,
 268                                       BdrvRequestFlags flags)
 269 {
 270     NFSClient *client = bs->opaque;
 271     NFSRPC task;
 272
 273     nfs_co_init_task(bs, &task);
 274     task.iov = iov;
 275
 276     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 277         if (nfs_pread_async(client->context, client->fh,
 278                             offset, bytes, nfs_co_generic_cb, &task) != 0) {
 279             return -ENOMEM;
 280         }
 281
 282         nfs_set_events(client);
 283     }
 284     while (!task.complete) {
 285         qemu_coroutine_yield();
 286     }
 287
 288     if (task.ret < 0) {
 289         return task.ret;
 290     }
 291
 292     /* zero pad short reads */
 293     if (task.ret < iov->size) {
 294         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 295     }
 296
 297     return 0;
 298 }
 299
 300 static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, int64_t offset,
 301                                        int64_t bytes, QEMUIOVector *iov,
 302                                        BdrvRequestFlags flags)
 303 {
 304     NFSClient *client = bs->opaque;
 305     NFSRPC task;
 306     char *buf = NULL;
 307     bool my_buffer = false;
 308
 309     nfs_co_init_task(bs, &task);
 310
 311     if (iov->niov != 1) {
 312         buf = g_try_malloc(bytes);
 313         if (bytes && buf == NULL) {
 314             return -ENOMEM;
 315         }
 316         qemu_iovec_to_buf(iov, 0, buf, bytes);
 317         my_buffer = true;
 318     } else {
 319         buf = iov->iov[0].iov_base;
 320     }
 321
 322     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 323         if (nfs_pwrite_async(client->context, client->fh,
 324                              offset, bytes, buf,
 325                              nfs_co_generic_cb, &task) != 0) {
 326             if (my_buffer) {
 327                 g_free(buf);
 328             }
 329             return -ENOMEM;
 330         }
 331
 332         nfs_set_events(client);
 333     }
 334     while (!task.complete) {
 335         qemu_coroutine_yield();
 336     }
 337
 338     if (my_buffer) {
 339         g_free(buf);
 340     }
 341
 342     if (task.ret != bytes) {
 343         return task.ret < 0 ? task.ret : -EIO;
 344     }
 345
 346     return 0;
 347 }
 348
 349 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 350 {
 351     NFSClient *client = bs->opaque;
 352     NFSRPC task;
 353
 354     nfs_co_init_task(bs, &task);
 355
 356     WITH_QEMU_LOCK_GUARD(&client->mutex) {
 357         if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 358                             &task) != 0) {
 359             return -ENOMEM;
 360         }
 361
 362         nfs_set_events(client);
 363     }
 364     while (!task.complete) {
 365         qemu_coroutine_yield();
 366     }
 367
 368     return task.ret;
 369 }
 370
 371 static void nfs_detach_aio_context(BlockDriverState *bs)
 372 {
 373     NFSClient *client = bs->opaque;
 374
 375     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 376                        false, NULL, NULL, NULL, NULL, NULL);
 377     client->events = 0;
 378 }
 379
 380 static void nfs_attach_aio_context(BlockDriverState *bs,
 381                                    AioContext *new_context)
 382 {
 383     NFSClient *client = bs->opaque;
 384
 385     client->aio_context = new_context;
 386     nfs_set_events(client);
 387 }
 388
 389 static void nfs_client_close(NFSClient *client)
 390 {
 391     if (client->context) {
 392         qemu_mutex_lock(&client->mutex);
 393         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 394                            false, NULL, NULL, NULL, NULL, NULL);
 395         qemu_mutex_unlock(&client->mutex);
 396         if (client->fh) {
 397             nfs_close(client->context, client->fh);
 398             client->fh = NULL;
 399         }
 400 #ifdef LIBNFS_FEATURE_UMOUNT
 401         nfs_umount(client->context);
 402 #endif
 403         nfs_destroy_context(client->context);
 404         client->context = NULL;
 405     }
 406     g_free(client->path);
 407     qemu_mutex_destroy(&client->mutex);
 408     qapi_free_NFSServer(client->server);
 409     client->server = NULL;
 410 }
 411
 412 static void nfs_file_close(BlockDriverState *bs)
 413 {
 414     NFSClient *client = bs->opaque;
 415     nfs_client_close(client);
 416 }
 417
 418 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 419                                int flags, int open_flags, Error **errp)
 420 {
 421     int64_t ret = -EINVAL;
 422 #ifdef _WIN32
 423     struct __stat64 st;
 424 #else
 425     struct stat st;
 426 #endif
 427     char *file = NULL, *strp = NULL;
 428
 429     qemu_mutex_init(&client->mutex);
 430
 431     client->path = g_strdup(opts->path);
 432
 433     strp = strrchr(client->path, '/');
 434     if (strp == NULL) {
 435         error_setg(errp, "Invalid URL specified");
 436         goto fail;
 437     }
 438     file = g_strdup(strp);
 439     *strp = 0;
 440
 441     /* Steal the NFSServer object from opts; set the original pointer to NULL
 442      * to avoid use after free and double free. */
 443     client->server = opts->server;
 444     opts->server = NULL;
 445
 446     client->context = nfs_init_context();
 447     if (client->context == NULL) {
 448         error_setg(errp, "Failed to init NFS context");
 449         goto fail;
 450     }
 451
 452     if (opts->has_user) {
 453         client->uid = opts->user;
 454         nfs_set_uid(client->context, client->uid);
 455     }
 456
 457     if (opts->has_group) {
 458         client->gid = opts->group;
 459         nfs_set_gid(client->context, client->gid);
 460     }
 461
 462     if (opts->has_tcp_syn_count) {
 463         client->tcp_syncnt = opts->tcp_syn_count;
 464         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 465     }
 466
 467 #ifdef LIBNFS_FEATURE_READAHEAD
 468     if (opts->has_readahead_size) {
 469         if (open_flags & BDRV_O_NOCACHE) {
 470             error_setg(errp, "Cannot enable NFS readahead "
 471                              "if cache.direct = on");
 472             goto fail;
 473         }
 474         client->readahead = opts->readahead_size;
 475         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 476             warn_report("Truncating NFS readahead size to %d",
 477                         QEMU_NFS_MAX_READAHEAD_SIZE);
 478             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 479         }
 480         nfs_set_readahead(client->context, client->readahead);
 481 #ifdef LIBNFS_FEATURE_PAGECACHE
 482         nfs_set_pagecache_ttl(client->context, 0);
 483 #endif
 484         client->cache_used = true;
 485     }
 486 #endif
 487
 488 #ifdef LIBNFS_FEATURE_PAGECACHE
 489     if (opts->has_page_cache_size) {
 490         if (open_flags & BDRV_O_NOCACHE) {
 491             error_setg(errp, "Cannot enable NFS pagecache "
 492                              "if cache.direct = on");
 493             goto fail;
 494         }
 495         client->pagecache = opts->page_cache_size;
 496         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 497             warn_report("Truncating NFS pagecache size to %d pages",
 498                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 499             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 500         }
 501         nfs_set_pagecache(client->context, client->pagecache);
 502         nfs_set_pagecache_ttl(client->context, 0);
 503         client->cache_used = true;
 504     }
 505 #endif
 506
 507 #ifdef LIBNFS_FEATURE_DEBUG
 508     if (opts->has_debug) {
 509         client->debug = opts->debug;
 510         /* limit the maximum debug level to avoid potential flooding
 511          * of our log files. */
 512         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 513             warn_report("Limiting NFS debug level to %d",
 514                         QEMU_NFS_MAX_DEBUG_LEVEL);
 515             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 516         }
 517         nfs_set_debug(client->context, client->debug);
 518     }
 519 #endif
 520
 521     ret = nfs_mount(client->context, client->server->host, client->path);
 522     if (ret < 0) {
 523         error_setg(errp, "Failed to mount nfs share: %s",
 524                    nfs_get_error(client->context));
 525         goto fail;
 526     }
 527
 528     if (flags & O_CREAT) {
 529         ret = nfs_creat(client->context, file, 0600, &client->fh);
 530         if (ret < 0) {
 531             error_setg(errp, "Failed to create file: %s",
 532                        nfs_get_error(client->context));
 533             goto fail;
 534         }
 535     } else {
 536         ret = nfs_open(client->context, file, flags, &client->fh);
 537         if (ret < 0) {
 538             error_setg(errp, "Failed to open file : %s",
 539                        nfs_get_error(client->context));
 540             goto fail;
 541         }
 542     }
 543
 544     ret = nfs_fstat(client->context, client->fh, &st);
 545     if (ret < 0) {
 546         error_setg(errp, "Failed to fstat file: %s",
 547                    nfs_get_error(client->context));
 548         goto fail;
 549     }
 550
 551     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 552 #if !defined(_WIN32)
 553     client->st_blocks = st.st_blocks;
 554 #endif
 555     client->has_zero_init = S_ISREG(st.st_mode);
 556     *strp = '/';
 557     goto out;
 558
 559 fail:
 560     nfs_client_close(client);
 561 out:
 562     g_free(file);
 563     return ret;
 564 }
 565
 566 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 567                                                      Error **errp)
 568 {
 569     BlockdevOptionsNfs *opts = NULL;
 570     Visitor *v;
 571     const QDictEntry *e;
 572
 573     v = qobject_input_visitor_new_flat_confused(options, errp);
 574     if (!v) {
 575         return NULL;
 576     }
 577
 578     visit_type_BlockdevOptionsNfs(v, NULL, &opts, errp);
 579     visit_free(v);
 580     if (!opts) {
 581         return NULL;
 582     }
 583
 584     /* Remove the processed options from the QDict (the visitor processes
 585      * _all_ options in the QDict) */
 586     while ((e = qdict_first(options))) {
 587         qdict_del(options, e->key);
 588     }
 589
 590     return opts;
 591 }
 592
 593 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 594                                      int flags, int open_flags, Error **errp)
 595 {
 596     BlockdevOptionsNfs *opts;
 597     int64_t ret;
 598
 599     opts = nfs_options_qdict_to_qapi(options, errp);
 600     if (opts == NULL) {
 601         ret = -EINVAL;
 602         goto fail;
 603     }
 604
 605     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 606 fail:
 607     qapi_free_BlockdevOptionsNfs(opts);
 608     return ret;
 609 }
 610
 611 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 612                          Error **errp) {
 613     NFSClient *client = bs->opaque;
 614     int64_t ret;
 615
 616     client->aio_context = bdrv_get_aio_context(bs);
 617
 618     ret = nfs_client_open_qdict(client, options,
 619                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 620                                 bs->open_flags, errp);
 621     if (ret < 0) {
 622         return ret;
 623     }
 624
 625     bs->total_sectors = ret;
 626     if (client->has_zero_init) {
 627         bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 628     }
 629     return 0;
 630 }
 631
 632 static QemuOptsList nfs_create_opts = {
 633     .name = "nfs-create-opts",
 634     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 635     .desc = {
 636         {
 637             .name = BLOCK_OPT_SIZE,
 638             .type = QEMU_OPT_SIZE,
 639             .help = "Virtual disk size"
 640         },
 641         { /* end of list */ }
 642     }
 643 };
 644
 645 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 646 {
 647     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 648     NFSClient *client = g_new0(NFSClient, 1);
 649     int ret;
 650
 651     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 652
 653     client->aio_context = qemu_get_aio_context();
 654
 655     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 656     if (ret < 0) {
 657         goto out;
 658     }
 659     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 660     nfs_client_close(client);
 661
 662 out:
 663     g_free(client);
 664     return ret;
 665 }
 666
 667 static int coroutine_fn nfs_file_co_create_opts(BlockDriver *drv,
 668                                                 const char *url,
 669                                                 QemuOpts *opts,
 670                                                 Error **errp)
 671 {
 672     BlockdevCreateOptions *create_options;
 673     BlockdevCreateOptionsNfs *nfs_opts;
 674     QDict *options;
 675     int ret;
 676
 677     create_options = g_new0(BlockdevCreateOptions, 1);
 678     create_options->driver = BLOCKDEV_DRIVER_NFS;
 679     nfs_opts = &create_options->u.nfs;
 680
 681     /* Read out options */
 682     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 683                               BDRV_SECTOR_SIZE);
 684
 685     options = qdict_new();
 686     ret = nfs_parse_uri(url, options, errp);
 687     if (ret < 0) {
 688         goto out;
 689     }
 690
 691     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 692     if (nfs_opts->location == NULL) {
 693         ret = -EINVAL;
 694         goto out;
 695     }
 696
 697     ret = nfs_file_co_create(create_options, errp);
 698     if (ret < 0) {
 699         goto out;
 700     }
 701
 702     ret = 0;
 703 out:
 704     qobject_unref(options);
 705     qapi_free_BlockdevCreateOptions(create_options);
 706     return ret;
 707 }
 708
 709 static int nfs_has_zero_init(BlockDriverState *bs)
 710 {
 711     NFSClient *client = bs->opaque;
 712     return client->has_zero_init;
 713 }
 714
 715 #if !defined(_WIN32)
 716 /* Called (via nfs_service) with QemuMutex held.  */
 717 static void
 718 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 719                                void *private_data)
 720 {
 721     NFSRPC *task = private_data;
 722     task->ret = ret;
 723     if (task->ret == 0) {
 724         memcpy(task->st, data, sizeof(struct stat));
 725     }
 726     if (task->ret < 0) {
 727         error_report("NFS Error: %s", nfs_get_error(nfs));
 728     }
 729
 730     /* Set task->complete before reading bs->wakeup.  */
 731     qatomic_mb_set(&task->complete, 1);
 732     bdrv_wakeup(task->bs);
 733 }
 734
 735 static int64_t coroutine_fn nfs_co_get_allocated_file_size(BlockDriverState *bs)
 736 {
 737     NFSClient *client = bs->opaque;
 738     NFSRPC task = {0};
 739     struct stat st;
 740
 741     if (bdrv_is_read_only(bs) &&
 742         !(bs->open_flags & BDRV_O_NOCACHE)) {
 743         return client->st_blocks * 512;
 744     }
 745
 746     task.bs = bs;
 747     task.st = &st;
 748     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 749                         &task) != 0) {
 750         return -ENOMEM;
 751     }
 752
 753     nfs_set_events(client);
 754     BDRV_POLL_WHILE(bs, !task.complete);
 755
 756     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 757 }
 758 #endif
 759
 760 static int coroutine_fn
 761 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 762                      PreallocMode prealloc, BdrvRequestFlags flags,
 763                      Error **errp)
 764 {
 765     NFSClient *client = bs->opaque;
 766     int ret;
 767
 768     if (prealloc != PREALLOC_MODE_OFF) {
 769         error_setg(errp, "Unsupported preallocation mode '%s'",
 770                    PreallocMode_str(prealloc));
 771         return -ENOTSUP;
 772     }
 773
 774     ret = nfs_ftruncate(client->context, client->fh, offset);
 775     if (ret < 0) {
 776         error_setg_errno(errp, -ret, "Failed to truncate file");
 777         return ret;
 778     }
 779
 780     return 0;
 781 }
 782
 783 /* Note that this will not re-establish a connection with the NFS server
 784  * - it is effectively a NOP.  */
 785 static int nfs_reopen_prepare(BDRVReopenState *state,
 786                               BlockReopenQueue *queue, Error **errp)
 787 {
 788     NFSClient *client = state->bs->opaque;
 789 #ifdef _WIN32
 790     struct __stat64 st;
 791 #else
 792     struct stat st;
 793 #endif
 794     int ret = 0;
 795
 796     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 797         error_setg(errp, "Cannot open a read-only mount as read-write");
 798         return -EACCES;
 799     }
 800
 801     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 802         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 803                          " pagecache is enabled");
 804         return -EINVAL;
 805     }
 806
 807     /* Update cache for read-only reopens */
 808     if (!(state->flags & BDRV_O_RDWR)) {
 809         ret = nfs_fstat(client->context, client->fh, &st);
 810         if (ret < 0) {
 811             error_setg(errp, "Failed to fstat file: %s",
 812                        nfs_get_error(client->context));
 813             return ret;
 814         }
 815 #if !defined(_WIN32)
 816         client->st_blocks = st.st_blocks;
 817 #endif
 818     }
 819
 820     return 0;
 821 }
 822
 823 static void nfs_refresh_filename(BlockDriverState *bs)
 824 {
 825     NFSClient *client = bs->opaque;
 826
 827     if (client->uid && !client->gid) {
 828         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 829                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 830                  client->uid);
 831     } else if (!client->uid && client->gid) {
 832         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 833                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 834                  client->gid);
 835     } else if (client->uid && client->gid) {
 836         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 837                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 838                  client->server->host, client->path, client->uid, client->gid);
 839     } else {
 840         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 841                  "nfs://%s%s", client->server->host, client->path);
 842     }
 843 }
 844
 845 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 846 {
 847     NFSClient *client = bs->opaque;
 848
 849     if (client->uid || client->gid) {
 850         bdrv_refresh_filename(bs);
 851         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 852                    bs->filename);
 853         return NULL;
 854     }
 855
 856     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 857 }
 858
 859 #ifdef LIBNFS_FEATURE_PAGECACHE
 860 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 861                                                  Error **errp)
 862 {
 863     NFSClient *client = bs->opaque;
 864     nfs_pagecache_invalidate(client->context, client->fh);
 865 }
 866 #endif
 867
 868 static const char *nfs_strong_runtime_opts[] = {
 869     "path",
 870     "user",
 871     "group",
 872     "server.",
 873
 874     NULL
 875 };
 876
 877 static BlockDriver bdrv_nfs = {
 878     .format_name                    = "nfs",
 879     .protocol_name                  = "nfs",
 880
 881     .instance_size                  = sizeof(NFSClient),
 882     .bdrv_parse_filename            = nfs_parse_filename,
 883     .create_opts                    = &nfs_create_opts,
 884
 885     .bdrv_has_zero_init             = nfs_has_zero_init,
 886 /* libnfs does not provide the allocated filesize of a file on win32. */
 887 #if !defined(_WIN32)
 888     .bdrv_co_get_allocated_file_size = nfs_co_get_allocated_file_size,
 889 #endif
 890     .bdrv_co_truncate               = nfs_file_co_truncate,
 891
 892     .bdrv_file_open                 = nfs_file_open,
 893     .bdrv_close                     = nfs_file_close,
 894     .bdrv_co_create                 = nfs_file_co_create,
 895     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 896     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 897
 898     .bdrv_co_preadv                 = nfs_co_preadv,
 899     .bdrv_co_pwritev                = nfs_co_pwritev,
 900     .bdrv_co_flush_to_disk          = nfs_co_flush,
 901
 902     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 903     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 904     .bdrv_refresh_filename          = nfs_refresh_filename,
 905     .bdrv_dirname                   = nfs_dirname,
 906
 907     .strong_runtime_opts            = nfs_strong_runtime_opts,
 908
 909 #ifdef LIBNFS_FEATURE_PAGECACHE
 910     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 911 #endif
 912 };
 913
 914 static void nfs_block_init(void)
 915 {
 916     bdrv_register(&bdrv_nfs);
 917 }
 918
 919 block_init(nfs_block_init);