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 #include <poll.h>
  28 #include "qemu/config-file.h"
  29 #include "qemu/error-report.h"
  30 #include "qapi/error.h"
  31 #include "block/block_int.h"
  32 #include "block/qdict.h"
  33 #include "trace.h"
  34 #include "qemu/iov.h"
  35 #include "qemu/main-loop.h"
  36 #include "qemu/module.h"
  37 #include "qemu/option.h"
  38 #include "qemu/uri.h"
  39 #include "qemu/cutils.h"
  40 #include "sysemu/sysemu.h"
  41 #include "sysemu/replay.h"
  42 #include "qapi/qapi-visit-block-core.h"
  43 #include "qapi/qmp/qdict.h"
  44 #include "qapi/qmp/qstring.h"
  45 #include "qapi/qobject-input-visitor.h"
  46 #include "qapi/qobject-output-visitor.h"
  47 #include <nfsc/libnfs.h>
  48
  49
  50 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  51 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  52 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  53
  54 typedef struct NFSClient {
  55     struct nfs_context *context;
  56     struct nfsfh *fh;
  57     int events;
  58     bool has_zero_init;
  59     AioContext *aio_context;
  60     QemuMutex mutex;
  61     blkcnt_t st_blocks;
  62     bool cache_used;
  63     NFSServer *server;
  64     char *path;
  65     int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug;
  66 } NFSClient;
  67
  68 typedef struct NFSRPC {
  69     BlockDriverState *bs;
  70     int ret;
  71     int complete;
  72     QEMUIOVector *iov;
  73     struct stat *st;
  74     Coroutine *co;
  75     NFSClient *client;
  76 } NFSRPC;
  77
  78 static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
  79 {
  80     URI *uri = NULL;
  81     QueryParams *qp = NULL;
  82     int ret = -EINVAL, i;
  83
  84     uri = uri_parse(filename);
  85     if (!uri) {
  86         error_setg(errp, "Invalid URI specified");
  87         goto out;
  88     }
  89     if (g_strcmp0(uri->scheme, "nfs") != 0) {
  90         error_setg(errp, "URI scheme must be 'nfs'");
  91         goto out;
  92     }
  93
  94     if (!uri->server) {
  95         error_setg(errp, "missing hostname in URI");
  96         goto out;
  97     }
  98
  99     if (!uri->path) {
 100         error_setg(errp, "missing file path in URI");
 101         goto out;
 102     }
 103
 104     qp = query_params_parse(uri->query);
 105     if (!qp) {
 106         error_setg(errp, "could not parse query parameters");
 107         goto out;
 108     }
 109
 110     qdict_put_str(options, "server.host", uri->server);
 111     qdict_put_str(options, "server.type", "inet");
 112     qdict_put_str(options, "path", uri->path);
 113
 114     for (i = 0; i < qp->n; i++) {
 115         unsigned long long val;
 116         if (!qp->p[i].value) {
 117             error_setg(errp, "Value for NFS parameter expected: %s",
 118                        qp->p[i].name);
 119             goto out;
 120         }
 121         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 122             error_setg(errp, "Illegal value for NFS parameter: %s",
 123                        qp->p[i].name);
 124             goto out;
 125         }
 126         if (!strcmp(qp->p[i].name, "uid")) {
 127             qdict_put_str(options, "user", qp->p[i].value);
 128         } else if (!strcmp(qp->p[i].name, "gid")) {
 129             qdict_put_str(options, "group", qp->p[i].value);
 130         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 131             qdict_put_str(options, "tcp-syn-count", qp->p[i].value);
 132         } else if (!strcmp(qp->p[i].name, "readahead")) {
 133             qdict_put_str(options, "readahead-size", qp->p[i].value);
 134         } else if (!strcmp(qp->p[i].name, "pagecache")) {
 135             qdict_put_str(options, "page-cache-size", qp->p[i].value);
 136         } else if (!strcmp(qp->p[i].name, "debug")) {
 137             qdict_put_str(options, "debug", qp->p[i].value);
 138         } else {
 139             error_setg(errp, "Unknown NFS parameter name: %s",
 140                        qp->p[i].name);
 141             goto out;
 142         }
 143     }
 144     ret = 0;
 145 out:
 146     if (qp) {
 147         query_params_free(qp);
 148     }
 149     if (uri) {
 150         uri_free(uri);
 151     }
 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, 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 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, uint64_t offset,
 267                                       uint64_t bytes, QEMUIOVector *iov,
 268                                       int flags)
 269 {
 270     NFSClient *client = bs->opaque;
 271     NFSRPC task;
 272
 273     nfs_co_init_task(bs, &task);
 274     task.iov = iov;
 275
 276     qemu_mutex_lock(&client->mutex);
 277     if (nfs_pread_async(client->context, client->fh,
 278                         offset, bytes, nfs_co_generic_cb, &task) != 0) {
 279         qemu_mutex_unlock(&client->mutex);
 280         return -ENOMEM;
 281     }
 282
 283     nfs_set_events(client);
 284     qemu_mutex_unlock(&client->mutex);
 285     while (!task.complete) {
 286         qemu_coroutine_yield();
 287     }
 288
 289     if (task.ret < 0) {
 290         return task.ret;
 291     }
 292
 293     /* zero pad short reads */
 294     if (task.ret < iov->size) {
 295         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 296     }
 297
 298     return 0;
 299 }
 300
 301 static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset,
 302                                        uint64_t bytes, QEMUIOVector *iov,
 303                                        int flags)
 304 {
 305     NFSClient *client = bs->opaque;
 306     NFSRPC task;
 307     char *buf = NULL;
 308     bool my_buffer = false;
 309
 310     nfs_co_init_task(bs, &task);
 311
 312     if (iov->niov != 1) {
 313         buf = g_try_malloc(bytes);
 314         if (bytes && buf == NULL) {
 315             return -ENOMEM;
 316         }
 317         qemu_iovec_to_buf(iov, 0, buf, bytes);
 318         my_buffer = true;
 319     } else {
 320         buf = iov->iov[0].iov_base;
 321     }
 322
 323     qemu_mutex_lock(&client->mutex);
 324     if (nfs_pwrite_async(client->context, client->fh,
 325                          offset, bytes, buf,
 326                          nfs_co_generic_cb, &task) != 0) {
 327         qemu_mutex_unlock(&client->mutex);
 328         if (my_buffer) {
 329             g_free(buf);
 330         }
 331         return -ENOMEM;
 332     }
 333
 334     nfs_set_events(client);
 335     qemu_mutex_unlock(&client->mutex);
 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     qemu_mutex_lock(&client->mutex);
 359     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 360                         &task) != 0) {
 361         qemu_mutex_unlock(&client->mutex);
 362         return -ENOMEM;
 363     }
 364
 365     nfs_set_events(client);
 366     qemu_mutex_unlock(&client->mutex);
 367     while (!task.complete) {
 368         qemu_coroutine_yield();
 369     }
 370
 371     return task.ret;
 372 }
 373
 374 static void nfs_detach_aio_context(BlockDriverState *bs)
 375 {
 376     NFSClient *client = bs->opaque;
 377
 378     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 379                        false, NULL, NULL, NULL, NULL);
 380     client->events = 0;
 381 }
 382
 383 static void nfs_attach_aio_context(BlockDriverState *bs,
 384                                    AioContext *new_context)
 385 {
 386     NFSClient *client = bs->opaque;
 387
 388     client->aio_context = new_context;
 389     nfs_set_events(client);
 390 }
 391
 392 static void nfs_client_close(NFSClient *client)
 393 {
 394     if (client->context) {
 395         qemu_mutex_lock(&client->mutex);
 396         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 397                            false, NULL, NULL, NULL, NULL);
 398         qemu_mutex_unlock(&client->mutex);
 399         if (client->fh) {
 400             nfs_close(client->context, client->fh);
 401             client->fh = NULL;
 402         }
 403 #ifdef LIBNFS_FEATURE_UMOUNT
 404         nfs_umount(client->context);
 405 #endif
 406         nfs_destroy_context(client->context);
 407         client->context = NULL;
 408     }
 409     g_free(client->path);
 410     qemu_mutex_destroy(&client->mutex);
 411     qapi_free_NFSServer(client->server);
 412     client->server = NULL;
 413 }
 414
 415 static void nfs_file_close(BlockDriverState *bs)
 416 {
 417     NFSClient *client = bs->opaque;
 418     nfs_client_close(client);
 419 }
 420
 421 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 422                                int flags, int open_flags, Error **errp)
 423 {
 424     int64_t ret = -EINVAL;
 425     struct stat st;
 426     char *file = NULL, *strp = NULL;
 427
 428     qemu_mutex_init(&client->mutex);
 429
 430     client->path = g_strdup(opts->path);
 431
 432     strp = strrchr(client->path, '/');
 433     if (strp == NULL) {
 434         error_setg(errp, "Invalid URL specified");
 435         goto fail;
 436     }
 437     file = g_strdup(strp);
 438     *strp = 0;
 439
 440     /* Steal the NFSServer object from opts; set the original pointer to NULL
 441      * to avoid use after free and double free. */
 442     client->server = opts->server;
 443     opts->server = NULL;
 444
 445     client->context = nfs_init_context();
 446     if (client->context == NULL) {
 447         error_setg(errp, "Failed to init NFS context");
 448         goto fail;
 449     }
 450
 451     if (opts->has_user) {
 452         client->uid = opts->user;
 453         nfs_set_uid(client->context, client->uid);
 454     }
 455
 456     if (opts->has_group) {
 457         client->gid = opts->group;
 458         nfs_set_gid(client->context, client->gid);
 459     }
 460
 461     if (opts->has_tcp_syn_count) {
 462         client->tcp_syncnt = opts->tcp_syn_count;
 463         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 464     }
 465
 466 #ifdef LIBNFS_FEATURE_READAHEAD
 467     if (opts->has_readahead_size) {
 468         if (open_flags & BDRV_O_NOCACHE) {
 469             error_setg(errp, "Cannot enable NFS readahead "
 470                              "if cache.direct = on");
 471             goto fail;
 472         }
 473         client->readahead = opts->readahead_size;
 474         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 475             warn_report("Truncating NFS readahead size to %d",
 476                         QEMU_NFS_MAX_READAHEAD_SIZE);
 477             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 478         }
 479         nfs_set_readahead(client->context, client->readahead);
 480 #ifdef LIBNFS_FEATURE_PAGECACHE
 481         nfs_set_pagecache_ttl(client->context, 0);
 482 #endif
 483         client->cache_used = true;
 484     }
 485 #endif
 486
 487 #ifdef LIBNFS_FEATURE_PAGECACHE
 488     if (opts->has_page_cache_size) {
 489         if (open_flags & BDRV_O_NOCACHE) {
 490             error_setg(errp, "Cannot enable NFS pagecache "
 491                              "if cache.direct = on");
 492             goto fail;
 493         }
 494         client->pagecache = opts->page_cache_size;
 495         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 496             warn_report("Truncating NFS pagecache size to %d pages",
 497                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 498             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 499         }
 500         nfs_set_pagecache(client->context, client->pagecache);
 501         nfs_set_pagecache_ttl(client->context, 0);
 502         client->cache_used = true;
 503     }
 504 #endif
 505
 506 #ifdef LIBNFS_FEATURE_DEBUG
 507     if (opts->has_debug) {
 508         client->debug = opts->debug;
 509         /* limit the maximum debug level to avoid potential flooding
 510          * of our log files. */
 511         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 512             warn_report("Limiting NFS debug level to %d",
 513                         QEMU_NFS_MAX_DEBUG_LEVEL);
 514             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 515         }
 516         nfs_set_debug(client->context, client->debug);
 517     }
 518 #endif
 519
 520     ret = nfs_mount(client->context, client->server->host, client->path);
 521     if (ret < 0) {
 522         error_setg(errp, "Failed to mount nfs share: %s",
 523                    nfs_get_error(client->context));
 524         goto fail;
 525     }
 526
 527     if (flags & O_CREAT) {
 528         ret = nfs_creat(client->context, file, 0600, &client->fh);
 529         if (ret < 0) {
 530             error_setg(errp, "Failed to create file: %s",
 531                        nfs_get_error(client->context));
 532             goto fail;
 533         }
 534     } else {
 535         ret = nfs_open(client->context, file, flags, &client->fh);
 536         if (ret < 0) {
 537             error_setg(errp, "Failed to open file : %s",
 538                        nfs_get_error(client->context));
 539             goto fail;
 540         }
 541     }
 542
 543     ret = nfs_fstat(client->context, client->fh, &st);
 544     if (ret < 0) {
 545         error_setg(errp, "Failed to fstat file: %s",
 546                    nfs_get_error(client->context));
 547         goto fail;
 548     }
 549
 550     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 551     client->st_blocks = st.st_blocks;
 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     Error *local_err = NULL;
 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, &local_err);
 577     visit_free(v);
 578
 579     if (local_err) {
 580         error_propagate(errp, local_err);
 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     int 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     ret = 0;
 627     return ret;
 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(const char *url, QemuOpts *opts,
 666                                                 Error **errp)
 667 {
 668     BlockdevCreateOptions *create_options;
 669     BlockdevCreateOptionsNfs *nfs_opts;
 670     QDict *options;
 671     int ret;
 672
 673     create_options = g_new0(BlockdevCreateOptions, 1);
 674     create_options->driver = BLOCKDEV_DRIVER_NFS;
 675     nfs_opts = &create_options->u.nfs;
 676
 677     /* Read out options */
 678     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 679                               BDRV_SECTOR_SIZE);
 680
 681     options = qdict_new();
 682     ret = nfs_parse_uri(url, options, errp);
 683     if (ret < 0) {
 684         goto out;
 685     }
 686
 687     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 688     if (nfs_opts->location == NULL) {
 689         ret = -EINVAL;
 690         goto out;
 691     }
 692
 693     ret = nfs_file_co_create(create_options, errp);
 694     if (ret < 0) {
 695         goto out;
 696     }
 697
 698     ret = 0;
 699 out:
 700     qobject_unref(options);
 701     qapi_free_BlockdevCreateOptions(create_options);
 702     return ret;
 703 }
 704
 705 static int nfs_has_zero_init(BlockDriverState *bs)
 706 {
 707     NFSClient *client = bs->opaque;
 708     return client->has_zero_init;
 709 }
 710
 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     atomic_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
 754 static int coroutine_fn
 755 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 756                      PreallocMode prealloc, Error **errp)
 757 {
 758     NFSClient *client = bs->opaque;
 759     int ret;
 760
 761     if (prealloc != PREALLOC_MODE_OFF) {
 762         error_setg(errp, "Unsupported preallocation mode '%s'",
 763                    PreallocMode_str(prealloc));
 764         return -ENOTSUP;
 765     }
 766
 767     ret = nfs_ftruncate(client->context, client->fh, offset);
 768     if (ret < 0) {
 769         error_setg_errno(errp, -ret, "Failed to truncate file");
 770         return ret;
 771     }
 772
 773     return 0;
 774 }
 775
 776 /* Note that this will not re-establish a connection with the NFS server
 777  * - it is effectively a NOP.  */
 778 static int nfs_reopen_prepare(BDRVReopenState *state,
 779                               BlockReopenQueue *queue, Error **errp)
 780 {
 781     NFSClient *client = state->bs->opaque;
 782     struct stat st;
 783     int ret = 0;
 784
 785     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 786         error_setg(errp, "Cannot open a read-only mount as read-write");
 787         return -EACCES;
 788     }
 789
 790     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 791         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 792                          " pagecache is enabled");
 793         return -EINVAL;
 794     }
 795
 796     /* Update cache for read-only reopens */
 797     if (!(state->flags & BDRV_O_RDWR)) {
 798         ret = nfs_fstat(client->context, client->fh, &st);
 799         if (ret < 0) {
 800             error_setg(errp, "Failed to fstat file: %s",
 801                        nfs_get_error(client->context));
 802             return ret;
 803         }
 804         client->st_blocks = st.st_blocks;
 805     }
 806
 807     return 0;
 808 }
 809
 810 static void nfs_refresh_filename(BlockDriverState *bs)
 811 {
 812     NFSClient *client = bs->opaque;
 813
 814     if (client->uid && !client->gid) {
 815         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 816                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 817                  client->uid);
 818     } else if (!client->uid && client->gid) {
 819         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 820                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 821                  client->gid);
 822     } else if (client->uid && client->gid) {
 823         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 824                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 825                  client->server->host, client->path, client->uid, client->gid);
 826     } else {
 827         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 828                  "nfs://%s%s", client->server->host, client->path);
 829     }
 830 }
 831
 832 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 833 {
 834     NFSClient *client = bs->opaque;
 835
 836     if (client->uid || client->gid) {
 837         bdrv_refresh_filename(bs);
 838         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 839                    bs->filename);
 840         return NULL;
 841     }
 842
 843     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 844 }
 845
 846 #ifdef LIBNFS_FEATURE_PAGECACHE
 847 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 848                                                  Error **errp)
 849 {
 850     NFSClient *client = bs->opaque;
 851     nfs_pagecache_invalidate(client->context, client->fh);
 852 }
 853 #endif
 854
 855 static const char *nfs_strong_runtime_opts[] = {
 856     "path",
 857     "user",
 858     "group",
 859     "server.",
 860
 861     NULL
 862 };
 863
 864 static BlockDriver bdrv_nfs = {
 865     .format_name                    = "nfs",
 866     .protocol_name                  = "nfs",
 867
 868     .instance_size                  = sizeof(NFSClient),
 869     .bdrv_parse_filename            = nfs_parse_filename,
 870     .create_opts                    = &nfs_create_opts,
 871
 872     .bdrv_has_zero_init             = nfs_has_zero_init,
 873     .bdrv_has_zero_init_truncate    = nfs_has_zero_init,
 874     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 875     .bdrv_co_truncate               = nfs_file_co_truncate,
 876
 877     .bdrv_file_open                 = nfs_file_open,
 878     .bdrv_close                     = nfs_file_close,
 879     .bdrv_co_create                 = nfs_file_co_create,
 880     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 881     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 882
 883     .bdrv_co_preadv                 = nfs_co_preadv,
 884     .bdrv_co_pwritev                = nfs_co_pwritev,
 885     .bdrv_co_flush_to_disk          = nfs_co_flush,
 886
 887     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 888     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 889     .bdrv_refresh_filename          = nfs_refresh_filename,
 890     .bdrv_dirname                   = nfs_dirname,
 891
 892     .strong_runtime_opts            = nfs_strong_runtime_opts,
 893
 894 #ifdef LIBNFS_FEATURE_PAGECACHE
 895     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 896 #endif
 897 };
 898
 899 static void nfs_block_init(void)
 900 {
 901     bdrv_register(&bdrv_nfs);
 902 }
 903
 904 block_init(nfs_block_init);