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     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, uint64_t offset,
 301                                        uint64_t bytes, QEMUIOVector *iov,
 302                                        int 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);
 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);
 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     struct stat st;
 423     char *file = NULL, *strp = NULL;
 424
 425     qemu_mutex_init(&client->mutex);
 426
 427     client->path = g_strdup(opts->path);
 428
 429     strp = strrchr(client->path, '/');
 430     if (strp == NULL) {
 431         error_setg(errp, "Invalid URL specified");
 432         goto fail;
 433     }
 434     file = g_strdup(strp);
 435     *strp = 0;
 436
 437     /* Steal the NFSServer object from opts; set the original pointer to NULL
 438      * to avoid use after free and double free. */
 439     client->server = opts->server;
 440     opts->server = NULL;
 441
 442     client->context = nfs_init_context();
 443     if (client->context == NULL) {
 444         error_setg(errp, "Failed to init NFS context");
 445         goto fail;
 446     }
 447
 448     if (opts->has_user) {
 449         client->uid = opts->user;
 450         nfs_set_uid(client->context, client->uid);
 451     }
 452
 453     if (opts->has_group) {
 454         client->gid = opts->group;
 455         nfs_set_gid(client->context, client->gid);
 456     }
 457
 458     if (opts->has_tcp_syn_count) {
 459         client->tcp_syncnt = opts->tcp_syn_count;
 460         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 461     }
 462
 463 #ifdef LIBNFS_FEATURE_READAHEAD
 464     if (opts->has_readahead_size) {
 465         if (open_flags & BDRV_O_NOCACHE) {
 466             error_setg(errp, "Cannot enable NFS readahead "
 467                              "if cache.direct = on");
 468             goto fail;
 469         }
 470         client->readahead = opts->readahead_size;
 471         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 472             warn_report("Truncating NFS readahead size to %d",
 473                         QEMU_NFS_MAX_READAHEAD_SIZE);
 474             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 475         }
 476         nfs_set_readahead(client->context, client->readahead);
 477 #ifdef LIBNFS_FEATURE_PAGECACHE
 478         nfs_set_pagecache_ttl(client->context, 0);
 479 #endif
 480         client->cache_used = true;
 481     }
 482 #endif
 483
 484 #ifdef LIBNFS_FEATURE_PAGECACHE
 485     if (opts->has_page_cache_size) {
 486         if (open_flags & BDRV_O_NOCACHE) {
 487             error_setg(errp, "Cannot enable NFS pagecache "
 488                              "if cache.direct = on");
 489             goto fail;
 490         }
 491         client->pagecache = opts->page_cache_size;
 492         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 493             warn_report("Truncating NFS pagecache size to %d pages",
 494                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 495             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 496         }
 497         nfs_set_pagecache(client->context, client->pagecache);
 498         nfs_set_pagecache_ttl(client->context, 0);
 499         client->cache_used = true;
 500     }
 501 #endif
 502
 503 #ifdef LIBNFS_FEATURE_DEBUG
 504     if (opts->has_debug) {
 505         client->debug = opts->debug;
 506         /* limit the maximum debug level to avoid potential flooding
 507          * of our log files. */
 508         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 509             warn_report("Limiting NFS debug level to %d",
 510                         QEMU_NFS_MAX_DEBUG_LEVEL);
 511             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 512         }
 513         nfs_set_debug(client->context, client->debug);
 514     }
 515 #endif
 516
 517     ret = nfs_mount(client->context, client->server->host, client->path);
 518     if (ret < 0) {
 519         error_setg(errp, "Failed to mount nfs share: %s",
 520                    nfs_get_error(client->context));
 521         goto fail;
 522     }
 523
 524     if (flags & O_CREAT) {
 525         ret = nfs_creat(client->context, file, 0600, &client->fh);
 526         if (ret < 0) {
 527             error_setg(errp, "Failed to create file: %s",
 528                        nfs_get_error(client->context));
 529             goto fail;
 530         }
 531     } else {
 532         ret = nfs_open(client->context, file, flags, &client->fh);
 533         if (ret < 0) {
 534             error_setg(errp, "Failed to open file : %s",
 535                        nfs_get_error(client->context));
 536             goto fail;
 537         }
 538     }
 539
 540     ret = nfs_fstat(client->context, client->fh, &st);
 541     if (ret < 0) {
 542         error_setg(errp, "Failed to fstat file: %s",
 543                    nfs_get_error(client->context));
 544         goto fail;
 545     }
 546
 547     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 548     client->st_blocks = st.st_blocks;
 549     client->has_zero_init = S_ISREG(st.st_mode);
 550     *strp = '/';
 551     goto out;
 552
 553 fail:
 554     nfs_client_close(client);
 555 out:
 556     g_free(file);
 557     return ret;
 558 }
 559
 560 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 561                                                      Error **errp)
 562 {
 563     BlockdevOptionsNfs *opts = NULL;
 564     Visitor *v;
 565     const QDictEntry *e;
 566     Error *local_err = NULL;
 567
 568     v = qobject_input_visitor_new_flat_confused(options, errp);
 569     if (!v) {
 570         return NULL;
 571     }
 572
 573     visit_type_BlockdevOptionsNfs(v, NULL, &opts, &local_err);
 574     visit_free(v);
 575
 576     if (local_err) {
 577         error_propagate(errp, local_err);
 578         return NULL;
 579     }
 580
 581     /* Remove the processed options from the QDict (the visitor processes
 582      * _all_ options in the QDict) */
 583     while ((e = qdict_first(options))) {
 584         qdict_del(options, e->key);
 585     }
 586
 587     return opts;
 588 }
 589
 590 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 591                                      int flags, int open_flags, Error **errp)
 592 {
 593     BlockdevOptionsNfs *opts;
 594     int ret;
 595
 596     opts = nfs_options_qdict_to_qapi(options, errp);
 597     if (opts == NULL) {
 598         ret = -EINVAL;
 599         goto fail;
 600     }
 601
 602     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 603 fail:
 604     qapi_free_BlockdevOptionsNfs(opts);
 605     return ret;
 606 }
 607
 608 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 609                          Error **errp) {
 610     NFSClient *client = bs->opaque;
 611     int64_t ret;
 612
 613     client->aio_context = bdrv_get_aio_context(bs);
 614
 615     ret = nfs_client_open_qdict(client, options,
 616                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 617                                 bs->open_flags, errp);
 618     if (ret < 0) {
 619         return ret;
 620     }
 621
 622     bs->total_sectors = ret;
 623     if (client->has_zero_init) {
 624         bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 625     }
 626     return 0;
 627 }
 628
 629 static QemuOptsList nfs_create_opts = {
 630     .name = "nfs-create-opts",
 631     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 632     .desc = {
 633         {
 634             .name = BLOCK_OPT_SIZE,
 635             .type = QEMU_OPT_SIZE,
 636             .help = "Virtual disk size"
 637         },
 638         { /* end of list */ }
 639     }
 640 };
 641
 642 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 643 {
 644     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 645     NFSClient *client = g_new0(NFSClient, 1);
 646     int ret;
 647
 648     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 649
 650     client->aio_context = qemu_get_aio_context();
 651
 652     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 653     if (ret < 0) {
 654         goto out;
 655     }
 656     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 657     nfs_client_close(client);
 658
 659 out:
 660     g_free(client);
 661     return ret;
 662 }
 663
 664 static int coroutine_fn nfs_file_co_create_opts(BlockDriver *drv,
 665                                                 const char *url,
 666                                                 QemuOpts *opts,
 667                                                 Error **errp)
 668 {
 669     BlockdevCreateOptions *create_options;
 670     BlockdevCreateOptionsNfs *nfs_opts;
 671     QDict *options;
 672     int ret;
 673
 674     create_options = g_new0(BlockdevCreateOptions, 1);
 675     create_options->driver = BLOCKDEV_DRIVER_NFS;
 676     nfs_opts = &create_options->u.nfs;
 677
 678     /* Read out options */
 679     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 680                               BDRV_SECTOR_SIZE);
 681
 682     options = qdict_new();
 683     ret = nfs_parse_uri(url, options, errp);
 684     if (ret < 0) {
 685         goto out;
 686     }
 687
 688     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 689     if (nfs_opts->location == NULL) {
 690         ret = -EINVAL;
 691         goto out;
 692     }
 693
 694     ret = nfs_file_co_create(create_options, errp);
 695     if (ret < 0) {
 696         goto out;
 697     }
 698
 699     ret = 0;
 700 out:
 701     qobject_unref(options);
 702     qapi_free_BlockdevCreateOptions(create_options);
 703     return ret;
 704 }
 705
 706 static int nfs_has_zero_init(BlockDriverState *bs)
 707 {
 708     NFSClient *client = bs->opaque;
 709     return client->has_zero_init;
 710 }
 711
 712 /* Called (via nfs_service) with QemuMutex held.  */
 713 static void
 714 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 715                                void *private_data)
 716 {
 717     NFSRPC *task = private_data;
 718     task->ret = ret;
 719     if (task->ret == 0) {
 720         memcpy(task->st, data, sizeof(struct stat));
 721     }
 722     if (task->ret < 0) {
 723         error_report("NFS Error: %s", nfs_get_error(nfs));
 724     }
 725
 726     /* Set task->complete before reading bs->wakeup.  */
 727     atomic_mb_set(&task->complete, 1);
 728     bdrv_wakeup(task->bs);
 729 }
 730
 731 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 732 {
 733     NFSClient *client = bs->opaque;
 734     NFSRPC task = {0};
 735     struct stat st;
 736
 737     if (bdrv_is_read_only(bs) &&
 738         !(bs->open_flags & BDRV_O_NOCACHE)) {
 739         return client->st_blocks * 512;
 740     }
 741
 742     task.bs = bs;
 743     task.st = &st;
 744     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 745                         &task) != 0) {
 746         return -ENOMEM;
 747     }
 748
 749     nfs_set_events(client);
 750     BDRV_POLL_WHILE(bs, !task.complete);
 751
 752     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 753 }
 754
 755 static int coroutine_fn
 756 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 757                      PreallocMode prealloc, BdrvRequestFlags flags,
 758                      Error **errp)
 759 {
 760     NFSClient *client = bs->opaque;
 761     int ret;
 762
 763     if (prealloc != PREALLOC_MODE_OFF) {
 764         error_setg(errp, "Unsupported preallocation mode '%s'",
 765                    PreallocMode_str(prealloc));
 766         return -ENOTSUP;
 767     }
 768
 769     ret = nfs_ftruncate(client->context, client->fh, offset);
 770     if (ret < 0) {
 771         error_setg_errno(errp, -ret, "Failed to truncate file");
 772         return ret;
 773     }
 774
 775     return 0;
 776 }
 777
 778 /* Note that this will not re-establish a connection with the NFS server
 779  * - it is effectively a NOP.  */
 780 static int nfs_reopen_prepare(BDRVReopenState *state,
 781                               BlockReopenQueue *queue, Error **errp)
 782 {
 783     NFSClient *client = state->bs->opaque;
 784     struct stat st;
 785     int ret = 0;
 786
 787     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 788         error_setg(errp, "Cannot open a read-only mount as read-write");
 789         return -EACCES;
 790     }
 791
 792     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 793         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 794                          " pagecache is enabled");
 795         return -EINVAL;
 796     }
 797
 798     /* Update cache for read-only reopens */
 799     if (!(state->flags & BDRV_O_RDWR)) {
 800         ret = nfs_fstat(client->context, client->fh, &st);
 801         if (ret < 0) {
 802             error_setg(errp, "Failed to fstat file: %s",
 803                        nfs_get_error(client->context));
 804             return ret;
 805         }
 806         client->st_blocks = st.st_blocks;
 807     }
 808
 809     return 0;
 810 }
 811
 812 static void nfs_refresh_filename(BlockDriverState *bs)
 813 {
 814     NFSClient *client = bs->opaque;
 815
 816     if (client->uid && !client->gid) {
 817         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 818                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 819                  client->uid);
 820     } else if (!client->uid && client->gid) {
 821         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 822                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 823                  client->gid);
 824     } else if (client->uid && client->gid) {
 825         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 826                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 827                  client->server->host, client->path, client->uid, client->gid);
 828     } else {
 829         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 830                  "nfs://%s%s", client->server->host, client->path);
 831     }
 832 }
 833
 834 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 835 {
 836     NFSClient *client = bs->opaque;
 837
 838     if (client->uid || client->gid) {
 839         bdrv_refresh_filename(bs);
 840         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 841                    bs->filename);
 842         return NULL;
 843     }
 844
 845     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 846 }
 847
 848 #ifdef LIBNFS_FEATURE_PAGECACHE
 849 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 850                                                  Error **errp)
 851 {
 852     NFSClient *client = bs->opaque;
 853     nfs_pagecache_invalidate(client->context, client->fh);
 854 }
 855 #endif
 856
 857 static const char *nfs_strong_runtime_opts[] = {
 858     "path",
 859     "user",
 860     "group",
 861     "server.",
 862
 863     NULL
 864 };
 865
 866 static BlockDriver bdrv_nfs = {
 867     .format_name                    = "nfs",
 868     .protocol_name                  = "nfs",
 869
 870     .instance_size                  = sizeof(NFSClient),
 871     .bdrv_parse_filename            = nfs_parse_filename,
 872     .create_opts                    = &nfs_create_opts,
 873
 874     .bdrv_has_zero_init             = nfs_has_zero_init,
 875     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 876     .bdrv_co_truncate               = nfs_file_co_truncate,
 877
 878     .bdrv_file_open                 = nfs_file_open,
 879     .bdrv_close                     = nfs_file_close,
 880     .bdrv_co_create                 = nfs_file_co_create,
 881     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 882     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 883
 884     .bdrv_co_preadv                 = nfs_co_preadv,
 885     .bdrv_co_pwritev                = nfs_co_pwritev,
 886     .bdrv_co_flush_to_disk          = nfs_co_flush,
 887
 888     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 889     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 890     .bdrv_refresh_filename          = nfs_refresh_filename,
 891     .bdrv_dirname                   = nfs_dirname,
 892
 893     .strong_runtime_opts            = nfs_strong_runtime_opts,
 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);