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