block/nfs.c

   1 /*
   2  * QEMU Block driver for native access to files on NFS shares
   3  *
   4  * Copyright (c) 2014-2016 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-common.h"
  29 #include "qemu/config-file.h"
  30 #include "qemu/error-report.h"
  31 #include "qapi/error.h"
  32 #include "block/block_int.h"
  33 #include "trace.h"
  34 #include "qemu/iov.h"
  35 #include "qemu/uri.h"
  36 #include "qemu/cutils.h"
  37 #include "sysemu/sysemu.h"
  38 #include "qapi/qmp/qdict.h"
  39 #include "qapi/qmp/qstring.h"
  40 #include "qapi-visit.h"
  41 #include "qapi/qobject-input-visitor.h"
  42 #include "qapi/qobject-output-visitor.h"
  43 #include <nfsc/libnfs.h>
  44
  45
  46 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  47 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  48 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  49
  50 typedef struct NFSClient {
  51     struct nfs_context *context;
  52     struct nfsfh *fh;
  53     int events;
  54     bool has_zero_init;
  55     AioContext *aio_context;
  56     QemuMutex mutex;
  57     blkcnt_t st_blocks;
  58     bool cache_used;
  59     NFSServer *server;
  60     char *path;
  61     int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug;
  62 } NFSClient;
  63
  64 typedef struct NFSRPC {
  65     BlockDriverState *bs;
  66     int ret;
  67     int complete;
  68     QEMUIOVector *iov;
  69     struct stat *st;
  70     Coroutine *co;
  71     NFSClient *client;
  72 } NFSRPC;
  73
  74 static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
  75 {
  76     URI *uri = NULL;
  77     QueryParams *qp = NULL;
  78     int ret = -EINVAL, i;
  79
  80     uri = uri_parse(filename);
  81     if (!uri) {
  82         error_setg(errp, "Invalid URI specified");
  83         goto out;
  84     }
  85     if (g_strcmp0(uri->scheme, "nfs") != 0) {
  86         error_setg(errp, "URI scheme must be 'nfs'");
  87         goto out;
  88     }
  89
  90     if (!uri->server) {
  91         error_setg(errp, "missing hostname in URI");
  92         goto out;
  93     }
  94
  95     if (!uri->path) {
  96         error_setg(errp, "missing file path in URI");
  97         goto out;
  98     }
  99
 100     qp = query_params_parse(uri->query);
 101     if (!qp) {
 102         error_setg(errp, "could not parse query parameters");
 103         goto out;
 104     }
 105
 106     qdict_put_str(options, "server.host", uri->server);
 107     qdict_put_str(options, "server.type", "inet");
 108     qdict_put_str(options, "path", uri->path);
 109
 110     for (i = 0; i < qp->n; i++) {
 111         unsigned long long val;
 112         if (!qp->p[i].value) {
 113             error_setg(errp, "Value for NFS parameter expected: %s",
 114                        qp->p[i].name);
 115             goto out;
 116         }
 117         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 118             error_setg(errp, "Illegal value for NFS parameter: %s",
 119                        qp->p[i].name);
 120             goto out;
 121         }
 122         if (!strcmp(qp->p[i].name, "uid")) {
 123             qdict_put_str(options, "user", qp->p[i].value);
 124         } else if (!strcmp(qp->p[i].name, "gid")) {
 125             qdict_put_str(options, "group", qp->p[i].value);
 126         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 127             qdict_put_str(options, "tcp-syn-count", qp->p[i].value);
 128         } else if (!strcmp(qp->p[i].name, "readahead")) {
 129             qdict_put_str(options, "readahead-size", qp->p[i].value);
 130         } else if (!strcmp(qp->p[i].name, "pagecache")) {
 131             qdict_put_str(options, "page-cache-size", qp->p[i].value);
 132         } else if (!strcmp(qp->p[i].name, "debug")) {
 133             qdict_put_str(options, "debug", qp->p[i].value);
 134         } else {
 135             error_setg(errp, "Unknown NFS parameter name: %s",
 136                        qp->p[i].name);
 137             goto out;
 138         }
 139     }
 140     ret = 0;
 141 out:
 142     if (qp) {
 143         query_params_free(qp);
 144     }
 145     if (uri) {
 146         uri_free(uri);
 147     }
 148     return ret;
 149 }
 150
 151 static bool nfs_has_filename_options_conflict(QDict *options, Error **errp)
 152 {
 153     const QDictEntry *qe;
 154
 155     for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
 156         if (!strcmp(qe->key, "host") ||
 157             !strcmp(qe->key, "path") ||
 158             !strcmp(qe->key, "user") ||
 159             !strcmp(qe->key, "group") ||
 160             !strcmp(qe->key, "tcp-syn-count") ||
 161             !strcmp(qe->key, "readahead-size") ||
 162             !strcmp(qe->key, "page-cache-size") ||
 163             !strcmp(qe->key, "debug") ||
 164             strstart(qe->key, "server.", NULL))
 165         {
 166             error_setg(errp, "Option %s cannot be used with a filename",
 167                        qe->key);
 168             return true;
 169         }
 170     }
 171
 172     return false;
 173 }
 174
 175 static void nfs_parse_filename(const char *filename, QDict *options,
 176                                Error **errp)
 177 {
 178     if (nfs_has_filename_options_conflict(options, errp)) {
 179         return;
 180     }
 181
 182     nfs_parse_uri(filename, options, errp);
 183 }
 184
 185 static void nfs_process_read(void *arg);
 186 static void nfs_process_write(void *arg);
 187
 188 /* Called with QemuMutex held.  */
 189 static void nfs_set_events(NFSClient *client)
 190 {
 191     int ev = nfs_which_events(client->context);
 192     if (ev != client->events) {
 193         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 194                            false,
 195                            (ev & POLLIN) ? nfs_process_read : NULL,
 196                            (ev & POLLOUT) ? nfs_process_write : NULL,
 197                            NULL, client);
 198
 199     }
 200     client->events = ev;
 201 }
 202
 203 static void nfs_process_read(void *arg)
 204 {
 205     NFSClient *client = arg;
 206
 207     qemu_mutex_lock(&client->mutex);
 208     nfs_service(client->context, POLLIN);
 209     nfs_set_events(client);
 210     qemu_mutex_unlock(&client->mutex);
 211 }
 212
 213 static void nfs_process_write(void *arg)
 214 {
 215     NFSClient *client = arg;
 216
 217     qemu_mutex_lock(&client->mutex);
 218     nfs_service(client->context, POLLOUT);
 219     nfs_set_events(client);
 220     qemu_mutex_unlock(&client->mutex);
 221 }
 222
 223 static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 224 {
 225     *task = (NFSRPC) {
 226         .co             = qemu_coroutine_self(),
 227         .bs             = bs,
 228         .client         = bs->opaque,
 229     };
 230 }
 231
 232 static void nfs_co_generic_bh_cb(void *opaque)
 233 {
 234     NFSRPC *task = opaque;
 235
 236     task->complete = 1;
 237     aio_co_wake(task->co);
 238 }
 239
 240 /* Called (via nfs_service) with QemuMutex held.  */
 241 static void
 242 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 243                   void *private_data)
 244 {
 245     NFSRPC *task = private_data;
 246     task->ret = ret;
 247     assert(!task->st);
 248     if (task->ret > 0 && task->iov) {
 249         if (task->ret <= task->iov->size) {
 250             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 251         } else {
 252             task->ret = -EIO;
 253         }
 254     }
 255     if (task->ret < 0) {
 256         error_report("NFS Error: %s", nfs_get_error(nfs));
 257     }
 258     aio_bh_schedule_oneshot(task->client->aio_context,
 259                             nfs_co_generic_bh_cb, task);
 260 }
 261
 262 static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, uint64_t offset,
 263                                       uint64_t bytes, QEMUIOVector *iov,
 264                                       int flags)
 265 {
 266     NFSClient *client = bs->opaque;
 267     NFSRPC task;
 268
 269     nfs_co_init_task(bs, &task);
 270     task.iov = iov;
 271
 272     qemu_mutex_lock(&client->mutex);
 273     if (nfs_pread_async(client->context, client->fh,
 274                         offset, bytes, nfs_co_generic_cb, &task) != 0) {
 275         qemu_mutex_unlock(&client->mutex);
 276         return -ENOMEM;
 277     }
 278
 279     nfs_set_events(client);
 280     qemu_mutex_unlock(&client->mutex);
 281     while (!task.complete) {
 282         qemu_coroutine_yield();
 283     }
 284
 285     if (task.ret < 0) {
 286         return task.ret;
 287     }
 288
 289     /* zero pad short reads */
 290     if (task.ret < iov->size) {
 291         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 292     }
 293
 294     return 0;
 295 }
 296
 297 static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset,
 298                                        uint64_t bytes, QEMUIOVector *iov,
 299                                        int flags)
 300 {
 301     NFSClient *client = bs->opaque;
 302     NFSRPC task;
 303     char *buf = NULL;
 304     bool my_buffer = false;
 305
 306     nfs_co_init_task(bs, &task);
 307
 308     if (iov->niov != 1) {
 309         buf = g_try_malloc(bytes);
 310         if (bytes && buf == NULL) {
 311             return -ENOMEM;
 312         }
 313         qemu_iovec_to_buf(iov, 0, buf, bytes);
 314         my_buffer = true;
 315     } else {
 316         buf = iov->iov[0].iov_base;
 317     }
 318
 319     qemu_mutex_lock(&client->mutex);
 320     if (nfs_pwrite_async(client->context, client->fh,
 321                          offset, bytes, buf,
 322                          nfs_co_generic_cb, &task) != 0) {
 323         qemu_mutex_unlock(&client->mutex);
 324         if (my_buffer) {
 325             g_free(buf);
 326         }
 327         return -ENOMEM;
 328     }
 329
 330     nfs_set_events(client);
 331     qemu_mutex_unlock(&client->mutex);
 332     while (!task.complete) {
 333         qemu_coroutine_yield();
 334     }
 335
 336     if (my_buffer) {
 337         g_free(buf);
 338     }
 339
 340     if (task.ret != bytes) {
 341         return task.ret < 0 ? task.ret : -EIO;
 342     }
 343
 344     return 0;
 345 }
 346
 347 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 348 {
 349     NFSClient *client = bs->opaque;
 350     NFSRPC task;
 351
 352     nfs_co_init_task(bs, &task);
 353
 354     qemu_mutex_lock(&client->mutex);
 355     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 356                         &task) != 0) {
 357         qemu_mutex_unlock(&client->mutex);
 358         return -ENOMEM;
 359     }
 360
 361     nfs_set_events(client);
 362     qemu_mutex_unlock(&client->mutex);
 363     while (!task.complete) {
 364         qemu_coroutine_yield();
 365     }
 366
 367     return task.ret;
 368 }
 369
 370 static QemuOptsList runtime_opts = {
 371     .name = "nfs",
 372     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 373     .desc = {
 374         {
 375             .name = "path",
 376             .type = QEMU_OPT_STRING,
 377             .help = "Path of the image on the host",
 378         },
 379         {
 380             .name = "user",
 381             .type = QEMU_OPT_NUMBER,
 382             .help = "UID value to use when talking to the server",
 383         },
 384         {
 385             .name = "group",
 386             .type = QEMU_OPT_NUMBER,
 387             .help = "GID value to use when talking to the server",
 388         },
 389         {
 390             .name = "tcp-syn-count",
 391             .type = QEMU_OPT_NUMBER,
 392             .help = "Number of SYNs to send during the session establish",
 393         },
 394         {
 395             .name = "readahead-size",
 396             .type = QEMU_OPT_NUMBER,
 397             .help = "Set the readahead size in bytes",
 398         },
 399         {
 400             .name = "page-cache-size",
 401             .type = QEMU_OPT_NUMBER,
 402             .help = "Set the pagecache size in bytes",
 403         },
 404         {
 405             .name = "debug",
 406             .type = QEMU_OPT_NUMBER,
 407             .help = "Set the NFS debug level (max 2)",
 408         },
 409         { /* end of list */ }
 410     },
 411 };
 412
 413 static void nfs_detach_aio_context(BlockDriverState *bs)
 414 {
 415     NFSClient *client = bs->opaque;
 416
 417     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 418                        false, NULL, NULL, NULL, NULL);
 419     client->events = 0;
 420 }
 421
 422 static void nfs_attach_aio_context(BlockDriverState *bs,
 423                                    AioContext *new_context)
 424 {
 425     NFSClient *client = bs->opaque;
 426
 427     client->aio_context = new_context;
 428     nfs_set_events(client);
 429 }
 430
 431 static void nfs_client_close(NFSClient *client)
 432 {
 433     if (client->context) {
 434         if (client->fh) {
 435             nfs_close(client->context, client->fh);
 436         }
 437         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 438                            false, NULL, NULL, NULL, NULL);
 439         nfs_destroy_context(client->context);
 440     }
 441     memset(client, 0, sizeof(NFSClient));
 442 }
 443
 444 static void nfs_file_close(BlockDriverState *bs)
 445 {
 446     NFSClient *client = bs->opaque;
 447     nfs_client_close(client);
 448     qemu_mutex_destroy(&client->mutex);
 449 }
 450
 451 static NFSServer *nfs_config(QDict *options, Error **errp)
 452 {
 453     NFSServer *server = NULL;
 454     QDict *addr = NULL;
 455     QObject *crumpled_addr = NULL;
 456     Visitor *iv = NULL;
 457     Error *local_error = NULL;
 458
 459     qdict_extract_subqdict(options, &addr, "server.");
 460     if (!qdict_size(addr)) {
 461         error_setg(errp, "NFS server address missing");
 462         goto out;
 463     }
 464
 465     crumpled_addr = qdict_crumple(addr, errp);
 466     if (!crumpled_addr) {
 467         goto out;
 468     }
 469
 470     /*
 471      * Caution: this works only because all scalar members of
 472      * NFSServer are QString in @crumpled_addr.  The visitor expects
 473      * @crumpled_addr to be typed according to the QAPI schema.  It
 474      * is when @options come from -blockdev or blockdev_add.  But when
 475      * they come from -drive, they're all QString.
 476      */
 477     iv = qobject_input_visitor_new(crumpled_addr);
 478     visit_type_NFSServer(iv, NULL, &server, &local_error);
 479     if (local_error) {
 480         error_propagate(errp, local_error);
 481         goto out;
 482     }
 483
 484 out:
 485     QDECREF(addr);
 486     qobject_decref(crumpled_addr);
 487     visit_free(iv);
 488     return server;
 489 }
 490
 491
 492 static int64_t nfs_client_open(NFSClient *client, QDict *options,
 493                                int flags, int open_flags, Error **errp)
 494 {
 495     int ret = -EINVAL;
 496     QemuOpts *opts = NULL;
 497     Error *local_err = NULL;
 498     struct stat st;
 499     char *file = NULL, *strp = NULL;
 500
 501     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 502     qemu_opts_absorb_qdict(opts, options, &local_err);
 503     if (local_err) {
 504         error_propagate(errp, local_err);
 505         ret = -EINVAL;
 506         goto fail;
 507     }
 508
 509     client->path = g_strdup(qemu_opt_get(opts, "path"));
 510     if (!client->path) {
 511         ret = -EINVAL;
 512         error_setg(errp, "No path was specified");
 513         goto fail;
 514     }
 515
 516     strp = strrchr(client->path, '/');
 517     if (strp == NULL) {
 518         error_setg(errp, "Invalid URL specified");
 519         goto fail;
 520     }
 521     file = g_strdup(strp);
 522     *strp = 0;
 523
 524     /* Pop the config into our state object, Exit if invalid */
 525     client->server = nfs_config(options, errp);
 526     if (!client->server) {
 527         ret = -EINVAL;
 528         goto fail;
 529     }
 530
 531     client->context = nfs_init_context();
 532     if (client->context == NULL) {
 533         error_setg(errp, "Failed to init NFS context");
 534         goto fail;
 535     }
 536
 537     if (qemu_opt_get(opts, "user")) {
 538         client->uid = qemu_opt_get_number(opts, "user", 0);
 539         nfs_set_uid(client->context, client->uid);
 540     }
 541
 542     if (qemu_opt_get(opts, "group")) {
 543         client->gid = qemu_opt_get_number(opts, "group", 0);
 544         nfs_set_gid(client->context, client->gid);
 545     }
 546
 547     if (qemu_opt_get(opts, "tcp-syn-count")) {
 548         client->tcp_syncnt = qemu_opt_get_number(opts, "tcp-syn-count", 0);
 549         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 550     }
 551
 552 #ifdef LIBNFS_FEATURE_READAHEAD
 553     if (qemu_opt_get(opts, "readahead-size")) {
 554         if (open_flags & BDRV_O_NOCACHE) {
 555             error_setg(errp, "Cannot enable NFS readahead "
 556                              "if cache.direct = on");
 557             goto fail;
 558         }
 559         client->readahead = qemu_opt_get_number(opts, "readahead-size", 0);
 560         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 561             warn_report("Truncating NFS readahead size to %d",
 562                         QEMU_NFS_MAX_READAHEAD_SIZE);
 563             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 564         }
 565         nfs_set_readahead(client->context, client->readahead);
 566 #ifdef LIBNFS_FEATURE_PAGECACHE
 567         nfs_set_pagecache_ttl(client->context, 0);
 568 #endif
 569         client->cache_used = true;
 570     }
 571 #endif
 572
 573 #ifdef LIBNFS_FEATURE_PAGECACHE
 574     if (qemu_opt_get(opts, "page-cache-size")) {
 575         if (open_flags & BDRV_O_NOCACHE) {
 576             error_setg(errp, "Cannot enable NFS pagecache "
 577                              "if cache.direct = on");
 578             goto fail;
 579         }
 580         client->pagecache = qemu_opt_get_number(opts, "page-cache-size", 0);
 581         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 582             warn_report("Truncating NFS pagecache size to %d pages",
 583                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 584             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 585         }
 586         nfs_set_pagecache(client->context, client->pagecache);
 587         nfs_set_pagecache_ttl(client->context, 0);
 588         client->cache_used = true;
 589     }
 590 #endif
 591
 592 #ifdef LIBNFS_FEATURE_DEBUG
 593     if (qemu_opt_get(opts, "debug")) {
 594         client->debug = qemu_opt_get_number(opts, "debug", 0);
 595         /* limit the maximum debug level to avoid potential flooding
 596          * of our log files. */
 597         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 598             warn_report("Limiting NFS debug level to %d",
 599                         QEMU_NFS_MAX_DEBUG_LEVEL);
 600             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 601         }
 602         nfs_set_debug(client->context, client->debug);
 603     }
 604 #endif
 605
 606     ret = nfs_mount(client->context, client->server->host, client->path);
 607     if (ret < 0) {
 608         error_setg(errp, "Failed to mount nfs share: %s",
 609                    nfs_get_error(client->context));
 610         goto fail;
 611     }
 612
 613     if (flags & O_CREAT) {
 614         ret = nfs_creat(client->context, file, 0600, &client->fh);
 615         if (ret < 0) {
 616             error_setg(errp, "Failed to create file: %s",
 617                        nfs_get_error(client->context));
 618             goto fail;
 619         }
 620     } else {
 621         ret = nfs_open(client->context, file, flags, &client->fh);
 622         if (ret < 0) {
 623             error_setg(errp, "Failed to open file : %s",
 624                        nfs_get_error(client->context));
 625             goto fail;
 626         }
 627     }
 628
 629     ret = nfs_fstat(client->context, client->fh, &st);
 630     if (ret < 0) {
 631         error_setg(errp, "Failed to fstat file: %s",
 632                    nfs_get_error(client->context));
 633         goto fail;
 634     }
 635
 636     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 637     client->st_blocks = st.st_blocks;
 638     client->has_zero_init = S_ISREG(st.st_mode);
 639     *strp = '/';
 640     goto out;
 641
 642 fail:
 643     nfs_client_close(client);
 644 out:
 645     qemu_opts_del(opts);
 646     g_free(file);
 647     return ret;
 648 }
 649
 650 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 651                          Error **errp) {
 652     NFSClient *client = bs->opaque;
 653     int64_t ret;
 654
 655     client->aio_context = bdrv_get_aio_context(bs);
 656
 657     ret = nfs_client_open(client, options,
 658                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 659                           bs->open_flags, errp);
 660     if (ret < 0) {
 661         return ret;
 662     }
 663     qemu_mutex_init(&client->mutex);
 664     bs->total_sectors = ret;
 665     ret = 0;
 666     return ret;
 667 }
 668
 669 static QemuOptsList nfs_create_opts = {
 670     .name = "nfs-create-opts",
 671     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 672     .desc = {
 673         {
 674             .name = BLOCK_OPT_SIZE,
 675             .type = QEMU_OPT_SIZE,
 676             .help = "Virtual disk size"
 677         },
 678         { /* end of list */ }
 679     }
 680 };
 681
 682 static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
 683 {
 684     int ret = 0;
 685     int64_t total_size = 0;
 686     NFSClient *client = g_new0(NFSClient, 1);
 687     QDict *options = NULL;
 688
 689     client->aio_context = qemu_get_aio_context();
 690
 691     /* Read out options */
 692     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 693                           BDRV_SECTOR_SIZE);
 694
 695     options = qdict_new();
 696     ret = nfs_parse_uri(url, options, errp);
 697     if (ret < 0) {
 698         goto out;
 699     }
 700
 701     ret = nfs_client_open(client, options, O_CREAT, 0, errp);
 702     if (ret < 0) {
 703         goto out;
 704     }
 705     ret = nfs_ftruncate(client->context, client->fh, total_size);
 706     nfs_client_close(client);
 707 out:
 708     QDECREF(options);
 709     g_free(client);
 710     return ret;
 711 }
 712
 713 static int nfs_has_zero_init(BlockDriverState *bs)
 714 {
 715     NFSClient *client = bs->opaque;
 716     return client->has_zero_init;
 717 }
 718
 719 /* Called (via nfs_service) with QemuMutex held.  */
 720 static void
 721 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 722                                void *private_data)
 723 {
 724     NFSRPC *task = private_data;
 725     task->ret = ret;
 726     if (task->ret == 0) {
 727         memcpy(task->st, data, sizeof(struct stat));
 728     }
 729     if (task->ret < 0) {
 730         error_report("NFS Error: %s", nfs_get_error(nfs));
 731     }
 732
 733     /* Set task->complete before reading bs->wakeup.  */
 734     atomic_mb_set(&task->complete, 1);
 735     bdrv_wakeup(task->bs);
 736 }
 737
 738 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 739 {
 740     NFSClient *client = bs->opaque;
 741     NFSRPC task = {0};
 742     struct stat st;
 743
 744     if (bdrv_is_read_only(bs) &&
 745         !(bs->open_flags & BDRV_O_NOCACHE)) {
 746         return client->st_blocks * 512;
 747     }
 748
 749     task.bs = bs;
 750     task.st = &st;
 751     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 752                         &task) != 0) {
 753         return -ENOMEM;
 754     }
 755
 756     nfs_set_events(client);
 757     BDRV_POLL_WHILE(bs, !task.complete);
 758
 759     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 760 }
 761
 762 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 763 {
 764     NFSClient *client = bs->opaque;
 765     int ret;
 766
 767     ret = nfs_ftruncate(client->context, client->fh, offset);
 768     if (ret < 0) {
 769         error_setg_errno(errp, -ret, "Failed to truncate file");
 770         return ret;
 771     }
 772
 773     return 0;
 774 }
 775
 776 /* Note that this will not re-establish a connection with the NFS server
 777  * - it is effectively a NOP.  */
 778 static int nfs_reopen_prepare(BDRVReopenState *state,
 779                               BlockReopenQueue *queue, Error **errp)
 780 {
 781     NFSClient *client = state->bs->opaque;
 782     struct stat st;
 783     int ret = 0;
 784
 785     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 786         error_setg(errp, "Cannot open a read-only mount as read-write");
 787         return -EACCES;
 788     }
 789
 790     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 791         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 792                          " pagecache is enabled");
 793         return -EINVAL;
 794     }
 795
 796     /* Update cache for read-only reopens */
 797     if (!(state->flags & BDRV_O_RDWR)) {
 798         ret = nfs_fstat(client->context, client->fh, &st);
 799         if (ret < 0) {
 800             error_setg(errp, "Failed to fstat file: %s",
 801                        nfs_get_error(client->context));
 802             return ret;
 803         }
 804         client->st_blocks = st.st_blocks;
 805     }
 806
 807     return 0;
 808 }
 809
 810 static void nfs_refresh_filename(BlockDriverState *bs, QDict *options)
 811 {
 812     NFSClient *client = bs->opaque;
 813     QDict *opts = qdict_new();
 814     QObject *server_qdict;
 815     Visitor *ov;
 816
 817     qdict_put_str(opts, "driver", "nfs");
 818
 819     if (client->uid && !client->gid) {
 820         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 821                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 822                  client->uid);
 823     } else if (!client->uid && client->gid) {
 824         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 825                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 826                  client->gid);
 827     } else if (client->uid && client->gid) {
 828         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 829                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 830                  client->server->host, client->path, client->uid, client->gid);
 831     } else {
 832         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 833                  "nfs://%s%s", client->server->host, client->path);
 834     }
 835
 836     ov = qobject_output_visitor_new(&server_qdict);
 837     visit_type_NFSServer(ov, NULL, &client->server, &error_abort);
 838     visit_complete(ov, &server_qdict);
 839     qdict_put_obj(opts, "server", server_qdict);
 840     qdict_put_str(opts, "path", client->path);
 841
 842     if (client->uid) {
 843         qdict_put_int(opts, "user", client->uid);
 844     }
 845     if (client->gid) {
 846         qdict_put_int(opts, "group", client->gid);
 847     }
 848     if (client->tcp_syncnt) {
 849         qdict_put_int(opts, "tcp-syn-cnt", client->tcp_syncnt);
 850     }
 851     if (client->readahead) {
 852         qdict_put_int(opts, "readahead-size", client->readahead);
 853     }
 854     if (client->pagecache) {
 855         qdict_put_int(opts, "page-cache-size", client->pagecache);
 856     }
 857     if (client->debug) {
 858         qdict_put_int(opts, "debug", client->debug);
 859     }
 860
 861     visit_free(ov);
 862     qdict_flatten(opts);
 863     bs->full_open_options = opts;
 864 }
 865
 866 #ifdef LIBNFS_FEATURE_PAGECACHE
 867 static void nfs_invalidate_cache(BlockDriverState *bs,
 868                                  Error **errp)
 869 {
 870     NFSClient *client = bs->opaque;
 871     nfs_pagecache_invalidate(client->context, client->fh);
 872 }
 873 #endif
 874
 875 static BlockDriver bdrv_nfs = {
 876     .format_name                    = "nfs",
 877     .protocol_name                  = "nfs",
 878
 879     .instance_size                  = sizeof(NFSClient),
 880     .bdrv_parse_filename            = nfs_parse_filename,
 881     .create_opts                    = &nfs_create_opts,
 882
 883     .bdrv_has_zero_init             = nfs_has_zero_init,
 884     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 885     .bdrv_truncate                  = nfs_file_truncate,
 886
 887     .bdrv_file_open                 = nfs_file_open,
 888     .bdrv_close                     = nfs_file_close,
 889     .bdrv_create                    = nfs_file_create,
 890     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 891
 892     .bdrv_co_preadv                 = nfs_co_preadv,
 893     .bdrv_co_pwritev                = nfs_co_pwritev,
 894     .bdrv_co_flush_to_disk          = nfs_co_flush,
 895
 896     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 897     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 898     .bdrv_refresh_filename          = nfs_refresh_filename,
 899
 900 #ifdef LIBNFS_FEATURE_PAGECACHE
 901     .bdrv_invalidate_cache          = nfs_invalidate_cache,
 902 #endif
 903 };
 904
 905 static void nfs_block_init(void)
 906 {
 907     bdrv_register(&bdrv_nfs);
 908 }
 909
 910 block_init(nfs_block_init);