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