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 "trace.h"
  33 #include "qemu/iov.h"
  34 #include "qemu/option.h"
  35 #include "qemu/uri.h"
  36 #include "qemu/cutils.h"
  37 #include "sysemu/sysemu.h"
  38 #include "qapi/qapi-visit-block-core.h"
  39 #include "qapi/qmp/qdict.h"
  40 #include "qapi/qmp/qstring.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 void nfs_detach_aio_context(BlockDriverState *bs)
 371 {
 372     NFSClient *client = bs->opaque;
 373
 374     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 375                        false, NULL, NULL, NULL, NULL);
 376     client->events = 0;
 377 }
 378
 379 static void nfs_attach_aio_context(BlockDriverState *bs,
 380                                    AioContext *new_context)
 381 {
 382     NFSClient *client = bs->opaque;
 383
 384     client->aio_context = new_context;
 385     nfs_set_events(client);
 386 }
 387
 388 static void nfs_client_close(NFSClient *client)
 389 {
 390     if (client->context) {
 391         if (client->fh) {
 392             nfs_close(client->context, client->fh);
 393             client->fh = NULL;
 394         }
 395         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 396                            false, NULL, NULL, NULL, NULL);
 397         nfs_destroy_context(client->context);
 398         client->context = NULL;
 399     }
 400     g_free(client->path);
 401     qemu_mutex_destroy(&client->mutex);
 402     qapi_free_NFSServer(client->server);
 403     client->server = NULL;
 404 }
 405
 406 static void nfs_file_close(BlockDriverState *bs)
 407 {
 408     NFSClient *client = bs->opaque;
 409     nfs_client_close(client);
 410 }
 411
 412 static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
 413                                int flags, int open_flags, Error **errp)
 414 {
 415     int64_t ret = -EINVAL;
 416     struct stat st;
 417     char *file = NULL, *strp = NULL;
 418
 419     qemu_mutex_init(&client->mutex);
 420
 421     client->path = g_strdup(opts->path);
 422
 423     strp = strrchr(client->path, '/');
 424     if (strp == NULL) {
 425         error_setg(errp, "Invalid URL specified");
 426         goto fail;
 427     }
 428     file = g_strdup(strp);
 429     *strp = 0;
 430
 431     /* Steal the NFSServer object from opts; set the original pointer to NULL
 432      * to avoid use after free and double free. */
 433     client->server = opts->server;
 434     opts->server = NULL;
 435
 436     client->context = nfs_init_context();
 437     if (client->context == NULL) {
 438         error_setg(errp, "Failed to init NFS context");
 439         goto fail;
 440     }
 441
 442     if (opts->has_user) {
 443         client->uid = opts->user;
 444         nfs_set_uid(client->context, client->uid);
 445     }
 446
 447     if (opts->has_group) {
 448         client->gid = opts->group;
 449         nfs_set_gid(client->context, client->gid);
 450     }
 451
 452     if (opts->has_tcp_syn_count) {
 453         client->tcp_syncnt = opts->tcp_syn_count;
 454         nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 455     }
 456
 457 #ifdef LIBNFS_FEATURE_READAHEAD
 458     if (opts->has_readahead_size) {
 459         if (open_flags & BDRV_O_NOCACHE) {
 460             error_setg(errp, "Cannot enable NFS readahead "
 461                              "if cache.direct = on");
 462             goto fail;
 463         }
 464         client->readahead = opts->readahead_size;
 465         if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 466             warn_report("Truncating NFS readahead size to %d",
 467                         QEMU_NFS_MAX_READAHEAD_SIZE);
 468             client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 469         }
 470         nfs_set_readahead(client->context, client->readahead);
 471 #ifdef LIBNFS_FEATURE_PAGECACHE
 472         nfs_set_pagecache_ttl(client->context, 0);
 473 #endif
 474         client->cache_used = true;
 475     }
 476 #endif
 477
 478 #ifdef LIBNFS_FEATURE_PAGECACHE
 479     if (opts->has_page_cache_size) {
 480         if (open_flags & BDRV_O_NOCACHE) {
 481             error_setg(errp, "Cannot enable NFS pagecache "
 482                              "if cache.direct = on");
 483             goto fail;
 484         }
 485         client->pagecache = opts->page_cache_size;
 486         if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 487             warn_report("Truncating NFS pagecache size to %d pages",
 488                         QEMU_NFS_MAX_PAGECACHE_SIZE);
 489             client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 490         }
 491         nfs_set_pagecache(client->context, client->pagecache);
 492         nfs_set_pagecache_ttl(client->context, 0);
 493         client->cache_used = true;
 494     }
 495 #endif
 496
 497 #ifdef LIBNFS_FEATURE_DEBUG
 498     if (opts->has_debug) {
 499         client->debug = opts->debug;
 500         /* limit the maximum debug level to avoid potential flooding
 501          * of our log files. */
 502         if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 503             warn_report("Limiting NFS debug level to %d",
 504                         QEMU_NFS_MAX_DEBUG_LEVEL);
 505             client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 506         }
 507         nfs_set_debug(client->context, client->debug);
 508     }
 509 #endif
 510
 511     ret = nfs_mount(client->context, client->server->host, client->path);
 512     if (ret < 0) {
 513         error_setg(errp, "Failed to mount nfs share: %s",
 514                    nfs_get_error(client->context));
 515         goto fail;
 516     }
 517
 518     if (flags & O_CREAT) {
 519         ret = nfs_creat(client->context, file, 0600, &client->fh);
 520         if (ret < 0) {
 521             error_setg(errp, "Failed to create file: %s",
 522                        nfs_get_error(client->context));
 523             goto fail;
 524         }
 525     } else {
 526         ret = nfs_open(client->context, file, flags, &client->fh);
 527         if (ret < 0) {
 528             error_setg(errp, "Failed to open file : %s",
 529                        nfs_get_error(client->context));
 530             goto fail;
 531         }
 532     }
 533
 534     ret = nfs_fstat(client->context, client->fh, &st);
 535     if (ret < 0) {
 536         error_setg(errp, "Failed to fstat file: %s",
 537                    nfs_get_error(client->context));
 538         goto fail;
 539     }
 540
 541     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 542     client->st_blocks = st.st_blocks;
 543     client->has_zero_init = S_ISREG(st.st_mode);
 544     *strp = '/';
 545     goto out;
 546
 547 fail:
 548     nfs_client_close(client);
 549 out:
 550     g_free(file);
 551     return ret;
 552 }
 553
 554 static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
 555                                                      Error **errp)
 556 {
 557     BlockdevOptionsNfs *opts = NULL;
 558     QObject *crumpled = NULL;
 559     Visitor *v;
 560     Error *local_err = NULL;
 561
 562     crumpled = qdict_crumple(options, errp);
 563     if (crumpled == NULL) {
 564         return NULL;
 565     }
 566
 567     v = qobject_input_visitor_new_keyval(crumpled);
 568     visit_type_BlockdevOptionsNfs(v, NULL, &opts, &local_err);
 569     visit_free(v);
 570     qobject_decref(crumpled);
 571
 572     if (local_err) {
 573         return NULL;
 574     }
 575
 576     return opts;
 577 }
 578
 579 static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options,
 580                                      int flags, int open_flags, Error **errp)
 581 {
 582     BlockdevOptionsNfs *opts;
 583     int ret;
 584
 585     opts = nfs_options_qdict_to_qapi(options, errp);
 586     if (opts == NULL) {
 587         ret = -EINVAL;
 588         goto fail;
 589     }
 590
 591     ret = nfs_client_open(client, opts, flags, open_flags, errp);
 592 fail:
 593     qapi_free_BlockdevOptionsNfs(opts);
 594     return ret;
 595 }
 596
 597 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 598                          Error **errp) {
 599     NFSClient *client = bs->opaque;
 600     int64_t ret;
 601
 602     client->aio_context = bdrv_get_aio_context(bs);
 603
 604     ret = nfs_client_open_qdict(client, options,
 605                                 (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 606                                 bs->open_flags, errp);
 607     if (ret < 0) {
 608         return ret;
 609     }
 610
 611     bs->total_sectors = ret;
 612     ret = 0;
 613     return ret;
 614 }
 615
 616 static QemuOptsList nfs_create_opts = {
 617     .name = "nfs-create-opts",
 618     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 619     .desc = {
 620         {
 621             .name = BLOCK_OPT_SIZE,
 622             .type = QEMU_OPT_SIZE,
 623             .help = "Virtual disk size"
 624         },
 625         { /* end of list */ }
 626     }
 627 };
 628
 629 static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp)
 630 {
 631     BlockdevCreateOptionsNfs *opts = &options->u.nfs;
 632     NFSClient *client = g_new0(NFSClient, 1);
 633     int ret;
 634
 635     assert(options->driver == BLOCKDEV_DRIVER_NFS);
 636
 637     client->aio_context = qemu_get_aio_context();
 638
 639     ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp);
 640     if (ret < 0) {
 641         goto out;
 642     }
 643     ret = nfs_ftruncate(client->context, client->fh, opts->size);
 644     nfs_client_close(client);
 645
 646 out:
 647     g_free(client);
 648     return ret;
 649 }
 650
 651 static int coroutine_fn nfs_file_co_create_opts(const char *url, QemuOpts *opts,
 652                                                 Error **errp)
 653 {
 654     BlockdevCreateOptions *create_options;
 655     BlockdevCreateOptionsNfs *nfs_opts;
 656     QDict *options;
 657     int ret;
 658
 659     create_options = g_new0(BlockdevCreateOptions, 1);
 660     create_options->driver = BLOCKDEV_DRIVER_NFS;
 661     nfs_opts = &create_options->u.nfs;
 662
 663     /* Read out options */
 664     nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 665                               BDRV_SECTOR_SIZE);
 666
 667     options = qdict_new();
 668     ret = nfs_parse_uri(url, options, errp);
 669     if (ret < 0) {
 670         goto out;
 671     }
 672
 673     nfs_opts->location = nfs_options_qdict_to_qapi(options, errp);
 674     if (nfs_opts->location == NULL) {
 675         ret = -EINVAL;
 676         goto out;
 677     }
 678
 679     ret = nfs_file_co_create(create_options, errp);
 680     if (ret < 0) {
 681         goto out;
 682     }
 683
 684     ret = 0;
 685 out:
 686     QDECREF(options);
 687     qapi_free_BlockdevCreateOptions(create_options);
 688     return ret;
 689 }
 690
 691 static int nfs_has_zero_init(BlockDriverState *bs)
 692 {
 693     NFSClient *client = bs->opaque;
 694     return client->has_zero_init;
 695 }
 696
 697 /* Called (via nfs_service) with QemuMutex held.  */
 698 static void
 699 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 700                                void *private_data)
 701 {
 702     NFSRPC *task = private_data;
 703     task->ret = ret;
 704     if (task->ret == 0) {
 705         memcpy(task->st, data, sizeof(struct stat));
 706     }
 707     if (task->ret < 0) {
 708         error_report("NFS Error: %s", nfs_get_error(nfs));
 709     }
 710
 711     /* Set task->complete before reading bs->wakeup.  */
 712     atomic_mb_set(&task->complete, 1);
 713     bdrv_wakeup(task->bs);
 714 }
 715
 716 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 717 {
 718     NFSClient *client = bs->opaque;
 719     NFSRPC task = {0};
 720     struct stat st;
 721
 722     if (bdrv_is_read_only(bs) &&
 723         !(bs->open_flags & BDRV_O_NOCACHE)) {
 724         return client->st_blocks * 512;
 725     }
 726
 727     task.bs = bs;
 728     task.st = &st;
 729     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 730                         &task) != 0) {
 731         return -ENOMEM;
 732     }
 733
 734     nfs_set_events(client);
 735     BDRV_POLL_WHILE(bs, !task.complete);
 736
 737     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 738 }
 739
 740 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset,
 741                              PreallocMode prealloc, Error **errp)
 742 {
 743     NFSClient *client = bs->opaque;
 744     int ret;
 745
 746     if (prealloc != PREALLOC_MODE_OFF) {
 747         error_setg(errp, "Unsupported preallocation mode '%s'",
 748                    PreallocMode_str(prealloc));
 749         return -ENOTSUP;
 750     }
 751
 752     ret = nfs_ftruncate(client->context, client->fh, offset);
 753     if (ret < 0) {
 754         error_setg_errno(errp, -ret, "Failed to truncate file");
 755         return ret;
 756     }
 757
 758     return 0;
 759 }
 760
 761 /* Note that this will not re-establish a connection with the NFS server
 762  * - it is effectively a NOP.  */
 763 static int nfs_reopen_prepare(BDRVReopenState *state,
 764                               BlockReopenQueue *queue, Error **errp)
 765 {
 766     NFSClient *client = state->bs->opaque;
 767     struct stat st;
 768     int ret = 0;
 769
 770     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 771         error_setg(errp, "Cannot open a read-only mount as read-write");
 772         return -EACCES;
 773     }
 774
 775     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 776         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 777                          " pagecache is enabled");
 778         return -EINVAL;
 779     }
 780
 781     /* Update cache for read-only reopens */
 782     if (!(state->flags & BDRV_O_RDWR)) {
 783         ret = nfs_fstat(client->context, client->fh, &st);
 784         if (ret < 0) {
 785             error_setg(errp, "Failed to fstat file: %s",
 786                        nfs_get_error(client->context));
 787             return ret;
 788         }
 789         client->st_blocks = st.st_blocks;
 790     }
 791
 792     return 0;
 793 }
 794
 795 static void nfs_refresh_filename(BlockDriverState *bs, QDict *options)
 796 {
 797     NFSClient *client = bs->opaque;
 798     QDict *opts = qdict_new();
 799     QObject *server_qdict;
 800     Visitor *ov;
 801
 802     qdict_put_str(opts, "driver", "nfs");
 803
 804     if (client->uid && !client->gid) {
 805         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 806                  "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 807                  client->uid);
 808     } else if (!client->uid && client->gid) {
 809         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 810                  "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 811                  client->gid);
 812     } else if (client->uid && client->gid) {
 813         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 814                  "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 815                  client->server->host, client->path, client->uid, client->gid);
 816     } else {
 817         snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 818                  "nfs://%s%s", client->server->host, client->path);
 819     }
 820
 821     ov = qobject_output_visitor_new(&server_qdict);
 822     visit_type_NFSServer(ov, NULL, &client->server, &error_abort);
 823     visit_complete(ov, &server_qdict);
 824     qdict_put_obj(opts, "server", server_qdict);
 825     qdict_put_str(opts, "path", client->path);
 826
 827     if (client->uid) {
 828         qdict_put_int(opts, "user", client->uid);
 829     }
 830     if (client->gid) {
 831         qdict_put_int(opts, "group", client->gid);
 832     }
 833     if (client->tcp_syncnt) {
 834         qdict_put_int(opts, "tcp-syn-cnt", client->tcp_syncnt);
 835     }
 836     if (client->readahead) {
 837         qdict_put_int(opts, "readahead-size", client->readahead);
 838     }
 839     if (client->pagecache) {
 840         qdict_put_int(opts, "page-cache-size", client->pagecache);
 841     }
 842     if (client->debug) {
 843         qdict_put_int(opts, "debug", client->debug);
 844     }
 845
 846     visit_free(ov);
 847     qdict_flatten(opts);
 848     bs->full_open_options = opts;
 849 }
 850
 851 #ifdef LIBNFS_FEATURE_PAGECACHE
 852 static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs,
 853                                                  Error **errp)
 854 {
 855     NFSClient *client = bs->opaque;
 856     nfs_pagecache_invalidate(client->context, client->fh);
 857 }
 858 #endif
 859
 860 static BlockDriver bdrv_nfs = {
 861     .format_name                    = "nfs",
 862     .protocol_name                  = "nfs",
 863
 864     .instance_size                  = sizeof(NFSClient),
 865     .bdrv_parse_filename            = nfs_parse_filename,
 866     .create_opts                    = &nfs_create_opts,
 867
 868     .bdrv_has_zero_init             = nfs_has_zero_init,
 869     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 870     .bdrv_truncate                  = nfs_file_truncate,
 871
 872     .bdrv_file_open                 = nfs_file_open,
 873     .bdrv_close                     = nfs_file_close,
 874     .bdrv_co_create                 = nfs_file_co_create,
 875     .bdrv_co_create_opts            = nfs_file_co_create_opts,
 876     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 877
 878     .bdrv_co_preadv                 = nfs_co_preadv,
 879     .bdrv_co_pwritev                = nfs_co_pwritev,
 880     .bdrv_co_flush_to_disk          = nfs_co_flush,
 881
 882     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 883     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 884     .bdrv_refresh_filename          = nfs_refresh_filename,
 885
 886 #ifdef LIBNFS_FEATURE_PAGECACHE
 887     .bdrv_co_invalidate_cache       = nfs_co_invalidate_cache,
 888 #endif
 889 };
 890
 891 static void nfs_block_init(void)
 892 {
 893     bdrv_register(&bdrv_nfs);
 894 }
 895
 896 block_init(nfs_block_init);