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 "qapi/qapi-visit-block-core.h"
  41 #include "qapi/qmp/qdict.h"
  42 #include "qapi/qmp/qstring.h"
  43 #include "qapi/qobject-input-visitor.h"
  44 #include "qapi/qobject-output-visitor.h"
  45 #include <nfsc/libnfs.h>
  46
  47
  48 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  49 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  50 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  51
  52 typedef struct NFSClient {
  53     struct nfs_context *context;
  54     struct nfsfh *fh;
  55     int events;
  56     bool has_zero_init;
  57     AioContext *aio_context;
  58     QemuMutex mutex;
  59     blkcnt_t st_blocks;
  60     bool cache_used;
  61     NFSServer *server;
  62     char *path;
  63     int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug;
  64 } NFSClient;
  65
  66 typedef struct NFSRPC {
  67     BlockDriverState *bs;
  68     int ret;
  69     int complete;
  70     QEMUIOVector *iov;
  71     struct stat *st;
  72     Coroutine *co;
  73     NFSClient *client;
  74 } NFSRPC;
  75
  76 static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
  77 {
  78     URI *uri = NULL;
  79     QueryParams *qp = NULL;
  80     int ret = -EINVAL, i;
  81
  82     uri = uri_parse(filename);
  83     if (!uri) {
  84         error_setg(errp, "Invalid URI specified");
  85         goto out;
  86     }
  87     if (g_strcmp0(uri->scheme, "nfs") != 0) {
  88         error_setg(errp, "URI scheme must be 'nfs'");
  89         goto out;
  90     }
  91
  92     if (!uri->server) {
  93         error_setg(errp, "missing hostname in URI");
  94         goto out;
  95     }
  96
  97     if (!uri->path) {
  98         error_setg(errp, "missing file path in URI");
  99         goto out;
 100     }
 101
 102     qp = query_params_parse(uri->query);
 103     if (!qp) {
 104         error_setg(errp, "could not parse query parameters");
 105         goto out;
 106     }
 107
 108     qdict_put_str(options, "server.host", uri->server);
 109     qdict_put_str(options, "server.type", "inet");
 110     qdict_put_str(options, "path", uri->path);
 111
 112     for (i = 0; i < qp->n; i++) {
 113         unsigned long long val;
 114         if (!qp->p[i].value) {
 115             error_setg(errp, "Value for NFS parameter expected: %s",
 116                        qp->p[i].name);
 117             goto out;
 118         }
 119         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 120             error_setg(errp, "Illegal value for NFS parameter: %s",
 121                        qp->p[i].name);
 122             goto out;
 123         }
 124         if (!strcmp(qp->p[i].name, "uid")) {
 125             qdict_put_str(options, "user", qp->p[i].value);
 126         } else if (!strcmp(qp->p[i].name, "gid")) {
 127             qdict_put_str(options, "group", qp->p[i].value);
 128         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 129             qdict_put_str(options, "tcp-syn-count", qp->p[i].value);
 130         } else if (!strcmp(qp->p[i].name, "readahead")) {
 131             qdict_put_str(options, "readahead-size", qp->p[i].value);
 132         } else if (!strcmp(qp->p[i].name, "pagecache")) {
 133             qdict_put_str(options, "page-cache-size", qp->p[i].value);
 134         } else if (!strcmp(qp->p[i].name, "debug")) {
 135             qdict_put_str(options, "debug", qp->p[i].value);
 136         } else {
 137             error_setg(errp, "Unknown NFS parameter name: %s",
 138                        qp->p[i].name);
 139             goto out;
 140         }
 141     }
 142     ret = 0;
 143 out:
 144     if (qp) {
 145         query_params_free(qp);
 146     }
 147     if (uri) {
 148         uri_free(uri);
 149     }
 150     return ret;
 151 }
 152
 153 static bool nfs_has_filename_options_conflict(QDict *options, Error **errp)
 154 {
 155     const QDictEntry *qe;
 156
 157     for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
 158         if (!strcmp(qe->key, "host") ||
 159             !strcmp(qe->key, "path") ||
 160             !strcmp(qe->key, "user") ||
 161             !strcmp(qe->key, "group") ||
 162             !strcmp(qe->key, "tcp-syn-count") ||
 163             !strcmp(qe->key, "readahead-size") ||
 164             !strcmp(qe->key, "page-cache-size") ||
 165             !strcmp(qe->key, "debug") ||
 166             strstart(qe->key, "server.", NULL))
 167         {
 168             error_setg(errp, "Option %s cannot be used with a filename",
 169                        qe->key);
 170             return true;
 171         }
 172     }
 173
 174     return false;
 175 }
 176
 177 static void nfs_parse_filename(const char *filename, QDict *options,
 178                                Error **errp)
 179 {
 180     if (nfs_has_filename_options_conflict(options, errp)) {
 181         return;
 182     }
 183
 184     nfs_parse_uri(filename, options, errp);
 185 }
 186
 187 static void nfs_process_read(void *arg);
 188 static void nfs_process_write(void *arg);
 189
 190 /* Called with QemuMutex held.  */
 191 static void nfs_set_events(NFSClient *client)
 192 {
 193     int ev = nfs_which_events(client->context);
 194     if (ev != client->events) {
 195         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 196                            false,
 197                            (ev & POLLIN) ? nfs_process_read : NULL,
 198                            (ev & POLLOUT) ? nfs_process_write : NULL,
 199                            NULL, client);
 200
 201     }
 202     client->events = ev;
 203 }
 204
 205 static void nfs_process_read(void *arg)
 206 {
 207     NFSClient *client = arg;
 208
 209     qemu_mutex_lock(&client->mutex);
 210     nfs_service(client->context, POLLIN);
 211     nfs_set_events(client);
 212     qemu_mutex_unlock(&client->mutex);
 213 }
 214
 215 static void nfs_process_write(void *arg)
 216 {
 217     NFSClient *client = arg;
 218
 219     qemu_mutex_lock(&client->mutex);
 220     nfs_service(client->context, POLLOUT);
 221     nfs_set_events(client);
 222     qemu_mutex_unlock(&client->mutex);
 223 }
 224
 225 static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 226 {
 227     *task = (NFSRPC) {
 228         .co             = qemu_coroutine_self(),
 229         .bs             = bs,
 230         .client         = bs->opaque,
 231     };
 232 }
 233
 234 static void nfs_co_generic_bh_cb(void *opaque)
 235 {
 236     NFSRPC *task = opaque;
 237
 238     task->complete = 1;
 239     aio_co_wake(task->co);
 240 }
 241
 242 /* Called (via nfs_service) with QemuMutex held.  */
 243 static void
 244 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 245                   void *private_data)
 246 {
 247     NFSRPC *task = private_data;
 248     task->ret = ret;
 249     assert(!task->st);
 250     if (task->ret > 0 && task->iov) {
 251         if (task->ret <= task->iov->size) {
 252             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 253         } else {
 254             task->ret = -EIO;
 255         }
 256     }
 257     if (task->ret < 0) {
 258         error_report("NFS Error: %s", nfs_get_error(nfs));
 259     }
 260     aio_bh_schedule_oneshot(task->client->aio_context,
 261                             nfs_co_generic_bh_cb, task);
 262 }
 263
 264 static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, uint64_t offset,
 265                                       uint64_t bytes, QEMUIOVector *iov,
 266                                       int flags)
 267 {
 268     NFSClient *client = bs->opaque;
 269     NFSRPC task;
 270
 271     nfs_co_init_task(bs, &task);
 272     task.iov = iov;
 273
 274     qemu_mutex_lock(&client->mutex);
 275     if (nfs_pread_async(client->context, client->fh,
 276                         offset, bytes, nfs_co_generic_cb, &task) != 0) {
 277         qemu_mutex_unlock(&client->mutex);
 278         return -ENOMEM;
 279     }
 280
 281     nfs_set_events(client);
 282     qemu_mutex_unlock(&client->mutex);
 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, uint64_t offset,
 300                                        uint64_t bytes, QEMUIOVector *iov,
 301                                        int 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     qemu_mutex_lock(&client->mutex);
 322     if (nfs_pwrite_async(client->context, client->fh,
 323                          offset, bytes, buf,
 324                          nfs_co_generic_cb, &task) != 0) {
 325         qemu_mutex_unlock(&client->mutex);
 326         if (my_buffer) {
 327             g_free(buf);
 328         }
 329         return -ENOMEM;
 330     }
 331
 332     nfs_set_events(client);
 333     qemu_mutex_unlock(&client->mutex);
 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     qemu_mutex_lock(&client->mutex);
 357     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 358                         &task) != 0) {
 359         qemu_mutex_unlock(&client->mutex);
 360         return -ENOMEM;
 361     }
 362
 363     nfs_set_events(client);
 364     qemu_mutex_unlock(&client->mutex);
 365     while (!task.complete) {
 366         qemu_coroutine_yield();
 367     }
 368
 369     return task.ret;
 370 }
 371
 372 static void nfs_detach_aio_context(BlockDriverState *bs)
 373 {
 374     NFSClient *client = bs->opaque;
 375
 376     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 377                        false, NULL, NULL, NULL, NULL);
 378     client->events = 0;
 379 }
 380
 381 static void nfs_attach_aio_context(BlockDriverState *bs,
 382                                    AioContext *new_context)
 383 {
 384     NFSClient *client = bs->opaque;
 385
 386     client->aio_context = new_context;
 387     nfs_set_events(client);
 388 }
 389
 390 static void nfs_client_close(NFSClient *client)
 391 {
 392     if (client->context) {
 393         qemu_mutex_lock(&client->mutex);
 394         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 395                            false, NULL, NULL, NULL, NULL);
 396         qemu_mutex_unlock(&client->mutex);
 397         if (client->fh) {
 398             nfs_close(client->context, client->fh);
 399             client->fh = NULL;
 400         }
 401         nfs_destroy_context(client->context);
 402         client->context = NULL;
 403     }
 404     g_free(client->path);
 405     qemu_mutex_destroy(&client->mutex);
 406     qapi_free_NFSServer(client->server);
 407     client->server = NULL;
 408 }
 409
 410 static void nfs_file_close(BlockDriverState *bs)
 411 {
 412     NFSClient *client = bs->opaque;
 413     nfs_client_close(client);
 414 }
 415
 416 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 417                                int flags, int open_flags, Error **errp)
 418 {
 419     int64_t ret = -EINVAL;
 420     struct stat st;
 421     char *file = NULL, *strp = NULL;
 422
 423     qemu_mutex_init(&client->mutex);
 424
 425     client->path = g_strdup(opts->path);
 426
 427     strp = strrchr(client->path, '/');
 428     if (strp == NULL) {
 429         error_setg(errp, "Invalid URL specified");
 430         goto fail;
 431     }
 432     file = g_strdup(strp);
 433     *strp = 0;
 434
 435     /* Steal the NFSServer object from opts; set the original pointer to NULL
 436      * to avoid use after free and double free. */
 437     client->server = opts->server;
 438     opts->server = NULL;
 439
 440     client->context = nfs_init_context();
 441     if (client->context == NULL) {
 442         error_setg(errp, "Failed to init NFS context");
 443         goto fail;
 444     }
 445
 446     if (opts->has_user) {
 447         client->uid = opts->user;
 448         nfs_set_uid(client->context, client->uid);
 449     }
 450
 451     if (opts->has_group) {
 452         client->gid = opts->group;
 453         nfs_set_gid(client->context, client->gid);
 454     }
 455
 456     if (opts->has_tcp_syn_count) {
 457         client->tcp_syncnt = opts->tcp_syn_count;
 458         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 459     }
 460
 461 #ifdef LIBNFS_FEATURE_READAHEAD
 462     if (opts->has_readahead_size) {
 463         if (open_flags & BDRV_O_NOCACHE) {
 464             error_setg(errp, "Cannot enable NFS readahead "
 465                              "if cache.direct = on");
 466             goto fail;
 467         }
 468         client->readahead = opts->readahead_size;
 469         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 470             warn_report("Truncating NFS readahead size to %d",
 471                         QEMU_NFS_MAX_READAHEAD_SIZE);
 472             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 473         }
 474         nfs_set_readahead(client->context, client->readahead);
 475 #ifdef LIBNFS_FEATURE_PAGECACHE
 476         nfs_set_pagecache_ttl(client->context, 0);
 477 #endif
 478         client->cache_used = true;
 479     }
 480 #endif
 481
 482 #ifdef LIBNFS_FEATURE_PAGECACHE
 483     if (opts->has_page_cache_size) {
 484         if (open_flags & BDRV_O_NOCACHE) {
 485             error_setg(errp, "Cannot enable NFS pagecache "
 486                              "if cache.direct = on");
 487             goto fail;
 488         }
 489         client->pagecache = opts->page_cache_size;
 490         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 491             warn_report("Truncating NFS pagecache size to %d pages",
 492                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 493             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 494         }
 495         nfs_set_pagecache(client->context, client->pagecache);
 496         nfs_set_pagecache_ttl(client->context, 0);
 497         client->cache_used = true;
 498     }
 499 #endif
 500
 501 #ifdef LIBNFS_FEATURE_DEBUG
 502     if (opts->has_debug) {
 503         client->debug = opts->debug;
 504         /* limit the maximum debug level to avoid potential flooding
 505          * of our log files. */
 506         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 507             warn_report("Limiting NFS debug level to %d",
 508                         QEMU_NFS_MAX_DEBUG_LEVEL);
 509             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 510         }
 511         nfs_set_debug(client->context, client->debug);
 512     }
 513 #endif
 514
 515     ret = nfs_mount(client->context, client->server->host, client->path);
 516     if (ret < 0) {
 517         error_setg(errp, "Failed to mount nfs share: %s",
 518                    nfs_get_error(client->context));
 519         goto fail;
 520     }
 521
 522     if (flags & O_CREAT) {
 523         ret = nfs_creat(client->context, file, 0600, &client->fh);
 524         if (ret < 0) {
 525             error_setg(errp, "Failed to create file: %s",
 526                        nfs_get_error(client->context));
 527             goto fail;
 528         }
 529     } else {
 530         ret = nfs_open(client->context, file, flags, &client->fh);
 531         if (ret < 0) {
 532             error_setg(errp, "Failed to open file : %s",
 533                        nfs_get_error(client->context));
 534             goto fail;
 535         }
 536     }
 537
 538     ret = nfs_fstat(client->context, client->fh, &st);
 539     if (ret < 0) {
 540         error_setg(errp, "Failed to fstat file: %s",
 541                    nfs_get_error(client->context));
 542         goto fail;
 543     }
 544
 545     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 546     client->st_blocks = st.st_blocks;
 547     client->has_zero_init = S_ISREG(st.st_mode);
 548     *strp = '/';
 549     goto out;
 550
 551 fail:
 552     nfs_client_close(client);
 553 out:
 554     g_free(file);
 555     return ret;
 556 }
 557
 558 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 559                                                      Error **errp)
 560 {
 561     BlockdevOptionsNfs *opts = NULL;
 562     Visitor *v;
 563     const QDictEntry *e;
 564     Error *local_err = NULL;
 565
 566     v = qobject_input_visitor_new_flat_confused(options, errp);
 567     if (!v) {
 568         return NULL;
 569     }
 570
 571     visit_type_BlockdevOptionsNfs(v, NULL, &opts, &local_err);
 572     visit_free(v);
 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 coroutine_fn
 750 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset,
 751                      PreallocMode prealloc, Error **errp)
 752 {
 753     NFSClient *client = bs->opaque;
 754     int ret;
 755
 756     if (prealloc != PREALLOC_MODE_OFF) {
 757         error_setg(errp, "Unsupported preallocation mode '%s'",
 758                    PreallocMode_str(prealloc));
 759         return -ENOTSUP;
 760     }
 761
 762     ret = nfs_ftruncate(client->context, client->fh, offset);
 763     if (ret < 0) {
 764         error_setg_errno(errp, -ret, "Failed to truncate file");
 765         return ret;
 766     }
 767
 768     return 0;
 769 }
 770
 771 /* Note that this will not re-establish a connection with the NFS server
 772  * - it is effectively a NOP.  */
 773 static int nfs_reopen_prepare(BDRVReopenState *state,
 774                               BlockReopenQueue *queue, Error **errp)
 775 {
 776     NFSClient *client = state->bs->opaque;
 777     struct stat st;
 778     int ret = 0;
 779
 780     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 781         error_setg(errp, "Cannot open a read-only mount as read-write");
 782         return -EACCES;
 783     }
 784
 785     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 786         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 787                          " pagecache is enabled");
 788         return -EINVAL;
 789     }
 790
 791     /* Update cache for read-only reopens */
 792     if (!(state->flags & BDRV_O_RDWR)) {
 793         ret = nfs_fstat(client->context, client->fh, &st);
 794         if (ret < 0) {
 795             error_setg(errp, "Failed to fstat file: %s",
 796                        nfs_get_error(client->context));
 797             return ret;
 798         }
 799         client->st_blocks = st.st_blocks;
 800     }
 801
 802     return 0;
 803 }
 804
 805 static void nfs_refresh_filename(BlockDriverState *bs)
 806 {
 807     NFSClient *client = bs->opaque;
 808
 809     if (client->uid && !client->gid) {
 810         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 811                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 812                  client->uid);
 813     } else if (!client->uid && client->gid) {
 814         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 815                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 816                  client->gid);
 817     } else if (client->uid && client->gid) {
 818         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 819                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 820                  client->server->host, client->path, client->uid, client->gid);
 821     } else {
 822         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 823                  "nfs://%s%s", client->server->host, client->path);
 824     }
 825 }
 826
 827 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 828 {
 829     NFSClient *client = bs->opaque;
 830
 831     if (client->uid || client->gid) {
 832         bdrv_refresh_filename(bs);
 833         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 834                    bs->filename);
 835         return NULL;
 836     }
 837
 838     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 839 }
 840
 841 #ifdef LIBNFS_FEATURE_PAGECACHE
 842 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 843                                                  Error **errp)
 844 {
 845     NFSClient *client = bs->opaque;
 846     nfs_pagecache_invalidate(client->context, client->fh);
 847 }
 848 #endif
 849
 850 static const char *nfs_strong_runtime_opts[] = {
 851     "path",
 852     "user",
 853     "group",
 854     "server.",
 855
 856     NULL
 857 };
 858
 859 static BlockDriver bdrv_nfs = {
 860     .format_name                    = "nfs",
 861     .protocol_name                  = "nfs",
 862
 863     .instance_size                  = sizeof(NFSClient),
 864     .bdrv_parse_filename            = nfs_parse_filename,
 865     .create_opts                    = &nfs_create_opts,
 866
 867     .bdrv_has_zero_init             = nfs_has_zero_init,
 868     .bdrv_has_zero_init_truncate    = nfs_has_zero_init,
 869     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 870     .bdrv_co_truncate               = nfs_file_co_truncate,
 871
 872     .bdrv_file_open                 = nfs_file_open,
 873     .bdrv_close                     = nfs_file_close,
 874     .bdrv_co_create                 = nfs_file_co_create,
 875     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 876     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 877
 878     .bdrv_co_preadv                 = nfs_co_preadv,
 879     .bdrv_co_pwritev                = nfs_co_pwritev,
 880     .bdrv_co_flush_to_disk          = nfs_co_flush,
 881
 882     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 883     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 884     .bdrv_refresh_filename          = nfs_refresh_filename,
 885     .bdrv_dirname                   = nfs_dirname,
 886
 887     .strong_runtime_opts            = nfs_strong_runtime_opts,
 888
 889 #ifdef LIBNFS_FEATURE_PAGECACHE
 890     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 891 #endif
 892 };
 893
 894 static void nfs_block_init(void)
 895 {
 896     bdrv_register(&bdrv_nfs);
 897 }
 898
 899 block_init(nfs_block_init);