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