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 #ifdef LIBNFS_FEATURE_UMOUNT
 402         nfs_umount(client->context);
 403 #endif
 404         nfs_destroy_context(client->context);
 405         client->context = NULL;
 406     }
 407     g_free(client->path);
 408     qemu_mutex_destroy(&client->mutex);
 409     qapi_free_NFSServer(client->server);
 410     client->server = NULL;
 411 }
 412
 413 static void nfs_file_close(BlockDriverState *bs)
 414 {
 415     NFSClient *client = bs->opaque;
 416     nfs_client_close(client);
 417 }
 418
 419 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 420                                int flags, int open_flags, Error **errp)
 421 {
 422     int64_t ret = -EINVAL;
 423     struct stat st;
 424     char *file = NULL, *strp = NULL;
 425
 426     qemu_mutex_init(&client->mutex);
 427
 428     client->path = g_strdup(opts->path);
 429
 430     strp = strrchr(client->path, '/');
 431     if (strp == NULL) {
 432         error_setg(errp, "Invalid URL specified");
 433         goto fail;
 434     }
 435     file = g_strdup(strp);
 436     *strp = 0;
 437
 438     /* Steal the NFSServer object from opts; set the original pointer to NULL
 439      * to avoid use after free and double free. */
 440     client->server = opts->server;
 441     opts->server = NULL;
 442
 443     client->context = nfs_init_context();
 444     if (client->context == NULL) {
 445         error_setg(errp, "Failed to init NFS context");
 446         goto fail;
 447     }
 448
 449     if (opts->has_user) {
 450         client->uid = opts->user;
 451         nfs_set_uid(client->context, client->uid);
 452     }
 453
 454     if (opts->has_group) {
 455         client->gid = opts->group;
 456         nfs_set_gid(client->context, client->gid);
 457     }
 458
 459     if (opts->has_tcp_syn_count) {
 460         client->tcp_syncnt = opts->tcp_syn_count;
 461         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 462     }
 463
 464 #ifdef LIBNFS_FEATURE_READAHEAD
 465     if (opts->has_readahead_size) {
 466         if (open_flags & BDRV_O_NOCACHE) {
 467             error_setg(errp, "Cannot enable NFS readahead "
 468                              "if cache.direct = on");
 469             goto fail;
 470         }
 471         client->readahead = opts->readahead_size;
 472         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 473             warn_report("Truncating NFS readahead size to %d",
 474                         QEMU_NFS_MAX_READAHEAD_SIZE);
 475             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 476         }
 477         nfs_set_readahead(client->context, client->readahead);
 478 #ifdef LIBNFS_FEATURE_PAGECACHE
 479         nfs_set_pagecache_ttl(client->context, 0);
 480 #endif
 481         client->cache_used = true;
 482     }
 483 #endif
 484
 485 #ifdef LIBNFS_FEATURE_PAGECACHE
 486     if (opts->has_page_cache_size) {
 487         if (open_flags & BDRV_O_NOCACHE) {
 488             error_setg(errp, "Cannot enable NFS pagecache "
 489                              "if cache.direct = on");
 490             goto fail;
 491         }
 492         client->pagecache = opts->page_cache_size;
 493         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 494             warn_report("Truncating NFS pagecache size to %d pages",
 495                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 496             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 497         }
 498         nfs_set_pagecache(client->context, client->pagecache);
 499         nfs_set_pagecache_ttl(client->context, 0);
 500         client->cache_used = true;
 501     }
 502 #endif
 503
 504 #ifdef LIBNFS_FEATURE_DEBUG
 505     if (opts->has_debug) {
 506         client->debug = opts->debug;
 507         /* limit the maximum debug level to avoid potential flooding
 508          * of our log files. */
 509         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 510             warn_report("Limiting NFS debug level to %d",
 511                         QEMU_NFS_MAX_DEBUG_LEVEL);
 512             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 513         }
 514         nfs_set_debug(client->context, client->debug);
 515     }
 516 #endif
 517
 518     ret = nfs_mount(client->context, client->server->host, client->path);
 519     if (ret < 0) {
 520         error_setg(errp, "Failed to mount nfs share: %s",
 521                    nfs_get_error(client->context));
 522         goto fail;
 523     }
 524
 525     if (flags & O_CREAT) {
 526         ret = nfs_creat(client->context, file, 0600, &client->fh);
 527         if (ret < 0) {
 528             error_setg(errp, "Failed to create file: %s",
 529                        nfs_get_error(client->context));
 530             goto fail;
 531         }
 532     } else {
 533         ret = nfs_open(client->context, file, flags, &client->fh);
 534         if (ret < 0) {
 535             error_setg(errp, "Failed to open file : %s",
 536                        nfs_get_error(client->context));
 537             goto fail;
 538         }
 539     }
 540
 541     ret = nfs_fstat(client->context, client->fh, &st);
 542     if (ret < 0) {
 543         error_setg(errp, "Failed to fstat file: %s",
 544                    nfs_get_error(client->context));
 545         goto fail;
 546     }
 547
 548     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 549     client->st_blocks = st.st_blocks;
 550     client->has_zero_init = S_ISREG(st.st_mode);
 551     *strp = '/';
 552     goto out;
 553
 554 fail:
 555     nfs_client_close(client);
 556 out:
 557     g_free(file);
 558     return ret;
 559 }
 560
 561 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 562                                                      Error **errp)
 563 {
 564     BlockdevOptionsNfs *opts = NULL;
 565     Visitor *v;
 566     const QDictEntry *e;
 567     Error *local_err = NULL;
 568
 569     v = qobject_input_visitor_new_flat_confused(options, errp);
 570     if (!v) {
 571         return NULL;
 572     }
 573
 574     visit_type_BlockdevOptionsNfs(v, NULL, &opts, &local_err);
 575     visit_free(v);
 576
 577     if (local_err) {
 578         error_propagate(errp, local_err);
 579         return NULL;
 580     }
 581
 582     /* Remove the processed options from the QDict (the visitor processes
 583      * _all_ options in the QDict) */
 584     while ((e = qdict_first(options))) {
 585         qdict_del(options, e->key);
 586     }
 587
 588     return opts;
 589 }
 590
 591 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 592                                      int flags, int open_flags, Error **errp)
 593 {
 594     BlockdevOptionsNfs *opts;
 595     int ret;
 596
 597     opts = nfs_options_qdict_to_qapi(options, errp);
 598     if (opts == NULL) {
 599         ret = -EINVAL;
 600         goto fail;
 601     }
 602
 603     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 604 fail:
 605     qapi_free_BlockdevOptionsNfs(opts);
 606     return ret;
 607 }
 608
 609 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 610                          Error **errp) {
 611     NFSClient *client = bs->opaque;
 612     int64_t ret;
 613
 614     client->aio_context = bdrv_get_aio_context(bs);
 615
 616     ret = nfs_client_open_qdict(client, options,
 617                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 618                                 bs->open_flags, errp);
 619     if (ret < 0) {
 620         return ret;
 621     }
 622
 623     bs->total_sectors = ret;
 624     ret = 0;
 625     return ret;
 626 }
 627
 628 static QemuOptsList nfs_create_opts = {
 629     .name = "nfs-create-opts",
 630     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 631     .desc = {
 632         {
 633             .name = BLOCK_OPT_SIZE,
 634             .type = QEMU_OPT_SIZE,
 635             .help = "Virtual disk size"
 636         },
 637         { /* end of list */ }
 638     }
 639 };
 640
 641 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 642 {
 643     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 644     NFSClient *client = g_new0(NFSClient, 1);
 645     int ret;
 646
 647     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 648
 649     client->aio_context = qemu_get_aio_context();
 650
 651     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 652     if (ret < 0) {
 653         goto out;
 654     }
 655     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 656     nfs_client_close(client);
 657
 658 out:
 659     g_free(client);
 660     return ret;
 661 }
 662
 663 static int coroutine_fn nfs_file_co_create_opts(const char *url, QemuOpts *opts,
 664                                                 Error **errp)
 665 {
 666     BlockdevCreateOptions *create_options;
 667     BlockdevCreateOptionsNfs *nfs_opts;
 668     QDict *options;
 669     int ret;
 670
 671     create_options = g_new0(BlockdevCreateOptions, 1);
 672     create_options->driver = BLOCKDEV_DRIVER_NFS;
 673     nfs_opts = &create_options->u.nfs;
 674
 675     /* Read out options */
 676     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 677                               BDRV_SECTOR_SIZE);
 678
 679     options = qdict_new();
 680     ret = nfs_parse_uri(url, options, errp);
 681     if (ret < 0) {
 682         goto out;
 683     }
 684
 685     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 686     if (nfs_opts->location == NULL) {
 687         ret = -EINVAL;
 688         goto out;
 689     }
 690
 691     ret = nfs_file_co_create(create_options, errp);
 692     if (ret < 0) {
 693         goto out;
 694     }
 695
 696     ret = 0;
 697 out:
 698     qobject_unref(options);
 699     qapi_free_BlockdevCreateOptions(create_options);
 700     return ret;
 701 }
 702
 703 static int nfs_has_zero_init(BlockDriverState *bs)
 704 {
 705     NFSClient *client = bs->opaque;
 706     return client->has_zero_init;
 707 }
 708
 709 /* Called (via nfs_service) with QemuMutex held.  */
 710 static void
 711 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 712                                void *private_data)
 713 {
 714     NFSRPC *task = private_data;
 715     task->ret = ret;
 716     if (task->ret == 0) {
 717         memcpy(task->st, data, sizeof(struct stat));
 718     }
 719     if (task->ret < 0) {
 720         error_report("NFS Error: %s", nfs_get_error(nfs));
 721     }
 722
 723     /* Set task->complete before reading bs->wakeup.  */
 724     atomic_mb_set(&task->complete, 1);
 725     bdrv_wakeup(task->bs);
 726 }
 727
 728 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 729 {
 730     NFSClient *client = bs->opaque;
 731     NFSRPC task = {0};
 732     struct stat st;
 733
 734     if (bdrv_is_read_only(bs) &&
 735         !(bs->open_flags & BDRV_O_NOCACHE)) {
 736         return client->st_blocks * 512;
 737     }
 738
 739     task.bs = bs;
 740     task.st = &st;
 741     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 742                         &task) != 0) {
 743         return -ENOMEM;
 744     }
 745
 746     nfs_set_events(client);
 747     BDRV_POLL_WHILE(bs, !task.complete);
 748
 749     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 750 }
 751
 752 static int coroutine_fn
 753 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset,
 754                      PreallocMode prealloc, Error **errp)
 755 {
 756     NFSClient *client = bs->opaque;
 757     int ret;
 758
 759     if (prealloc != PREALLOC_MODE_OFF) {
 760         error_setg(errp, "Unsupported preallocation mode '%s'",
 761                    PreallocMode_str(prealloc));
 762         return -ENOTSUP;
 763     }
 764
 765     ret = nfs_ftruncate(client->context, client->fh, offset);
 766     if (ret < 0) {
 767         error_setg_errno(errp, -ret, "Failed to truncate file");
 768         return ret;
 769     }
 770
 771     return 0;
 772 }
 773
 774 /* Note that this will not re-establish a connection with the NFS server
 775  * - it is effectively a NOP.  */
 776 static int nfs_reopen_prepare(BDRVReopenState *state,
 777                               BlockReopenQueue *queue, Error **errp)
 778 {
 779     NFSClient *client = state->bs->opaque;
 780     struct stat st;
 781     int ret = 0;
 782
 783     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 784         error_setg(errp, "Cannot open a read-only mount as read-write");
 785         return -EACCES;
 786     }
 787
 788     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 789         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 790                          " pagecache is enabled");
 791         return -EINVAL;
 792     }
 793
 794     /* Update cache for read-only reopens */
 795     if (!(state->flags & BDRV_O_RDWR)) {
 796         ret = nfs_fstat(client->context, client->fh, &st);
 797         if (ret < 0) {
 798             error_setg(errp, "Failed to fstat file: %s",
 799                        nfs_get_error(client->context));
 800             return ret;
 801         }
 802         client->st_blocks = st.st_blocks;
 803     }
 804
 805     return 0;
 806 }
 807
 808 static void nfs_refresh_filename(BlockDriverState *bs)
 809 {
 810     NFSClient *client = bs->opaque;
 811
 812     if (client->uid && !client->gid) {
 813         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 814                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 815                  client->uid);
 816     } else if (!client->uid && client->gid) {
 817         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 818                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 819                  client->gid);
 820     } else if (client->uid && client->gid) {
 821         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 822                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 823                  client->server->host, client->path, client->uid, client->gid);
 824     } else {
 825         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 826                  "nfs://%s%s", client->server->host, client->path);
 827     }
 828 }
 829
 830 static char *nfs_dirname(BlockDriverState *bs, Error **errp)
 831 {
 832     NFSClient *client = bs->opaque;
 833
 834     if (client->uid || client->gid) {
 835         bdrv_refresh_filename(bs);
 836         error_setg(errp, "Cannot generate a base directory for NFS node '%s'",
 837                    bs->filename);
 838         return NULL;
 839     }
 840
 841     return g_strdup_printf("nfs://%s%s/", client->server->host, client->path);
 842 }
 843
 844 #ifdef LIBNFS_FEATURE_PAGECACHE
 845 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 846                                                  Error **errp)
 847 {
 848     NFSClient *client = bs->opaque;
 849     nfs_pagecache_invalidate(client->context, client->fh);
 850 }
 851 #endif
 852
 853 static const char *nfs_strong_runtime_opts[] = {
 854     "path",
 855     "user",
 856     "group",
 857     "server.",
 858
 859     NULL
 860 };
 861
 862 static BlockDriver bdrv_nfs = {
 863     .format_name                    = "nfs",
 864     .protocol_name                  = "nfs",
 865
 866     .instance_size                  = sizeof(NFSClient),
 867     .bdrv_parse_filename            = nfs_parse_filename,
 868     .create_opts                    = &nfs_create_opts,
 869
 870     .bdrv_has_zero_init             = nfs_has_zero_init,
 871     .bdrv_has_zero_init_truncate    = nfs_has_zero_init,
 872     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 873     .bdrv_co_truncate               = nfs_file_co_truncate,
 874
 875     .bdrv_file_open                 = nfs_file_open,
 876     .bdrv_close                     = nfs_file_close,
 877     .bdrv_co_create                 = nfs_file_co_create,
 878     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 879     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 880
 881     .bdrv_co_preadv                 = nfs_co_preadv,
 882     .bdrv_co_pwritev                = nfs_co_pwritev,
 883     .bdrv_co_flush_to_disk          = nfs_co_flush,
 884
 885     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 886     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 887     .bdrv_refresh_filename          = nfs_refresh_filename,
 888     .bdrv_dirname                   = nfs_dirname,
 889
 890     .strong_runtime_opts            = nfs_strong_runtime_opts,
 891
 892 #ifdef LIBNFS_FEATURE_PAGECACHE
 893     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 894 #endif
 895 };
 896
 897 static void nfs_block_init(void)
 898 {
 899     bdrv_register(&bdrv_nfs);
 900 }
 901
 902 block_init(nfs_block_init);