qemu/block/nfs.c
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   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
  51typedef 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
  64typedef 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
  74static 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;
 147out:
 148    if (qp) {
 149        query_params_free(qp);
 150    }
 151    if (uri) {
 152        uri_free(uri);
 153    }
 154    return ret;
 155}
 156
 157static 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
 181static 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
 191static void nfs_process_read(void *arg);
 192static void nfs_process_write(void *arg);
 193
 194static 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, client);
 202
 203    }
 204    client->events = ev;
 205}
 206
 207static void nfs_process_read(void *arg)
 208{
 209    NFSClient *client = arg;
 210    nfs_service(client->context, POLLIN);
 211    nfs_set_events(client);
 212}
 213
 214static void nfs_process_write(void *arg)
 215{
 216    NFSClient *client = arg;
 217    nfs_service(client->context, POLLOUT);
 218    nfs_set_events(client);
 219}
 220
 221static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 222{
 223    *task = (NFSRPC) {
 224        .co             = qemu_coroutine_self(),
 225        .bs             = bs,
 226        .client         = bs->opaque,
 227    };
 228}
 229
 230static void nfs_co_generic_bh_cb(void *opaque)
 231{
 232    NFSRPC *task = opaque;
 233    task->complete = 1;
 234    qemu_coroutine_enter(task->co);
 235}
 236
 237static void
 238nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 239                  void *private_data)
 240{
 241    NFSRPC *task = private_data;
 242    task->ret = ret;
 243    assert(!task->st);
 244    if (task->ret > 0 && task->iov) {
 245        if (task->ret <= task->iov->size) {
 246            qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 247        } else {
 248            task->ret = -EIO;
 249        }
 250    }
 251    if (task->ret < 0) {
 252        error_report("NFS Error: %s", nfs_get_error(nfs));
 253    }
 254    aio_bh_schedule_oneshot(task->client->aio_context,
 255                            nfs_co_generic_bh_cb, task);
 256}
 257
 258static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 259                                     int64_t sector_num, int nb_sectors,
 260                                     QEMUIOVector *iov)
 261{
 262    NFSClient *client = bs->opaque;
 263    NFSRPC task;
 264
 265    nfs_co_init_task(bs, &task);
 266    task.iov = iov;
 267
 268    if (nfs_pread_async(client->context, client->fh,
 269                        sector_num * BDRV_SECTOR_SIZE,
 270                        nb_sectors * BDRV_SECTOR_SIZE,
 271                        nfs_co_generic_cb, &task) != 0) {
 272        return -ENOMEM;
 273    }
 274
 275    nfs_set_events(client);
 276    while (!task.complete) {
 277        qemu_coroutine_yield();
 278    }
 279
 280    if (task.ret < 0) {
 281        return task.ret;
 282    }
 283
 284    /* zero pad short reads */
 285    if (task.ret < iov->size) {
 286        qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 287    }
 288
 289    return 0;
 290}
 291
 292static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 293                                        int64_t sector_num, int nb_sectors,
 294                                        QEMUIOVector *iov)
 295{
 296    NFSClient *client = bs->opaque;
 297    NFSRPC task;
 298    char *buf = NULL;
 299
 300    nfs_co_init_task(bs, &task);
 301
 302    buf = g_try_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 303    if (nb_sectors && buf == NULL) {
 304        return -ENOMEM;
 305    }
 306
 307    qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 308
 309    if (nfs_pwrite_async(client->context, client->fh,
 310                         sector_num * BDRV_SECTOR_SIZE,
 311                         nb_sectors * BDRV_SECTOR_SIZE,
 312                         buf, nfs_co_generic_cb, &task) != 0) {
 313        g_free(buf);
 314        return -ENOMEM;
 315    }
 316
 317    nfs_set_events(client);
 318    while (!task.complete) {
 319        qemu_coroutine_yield();
 320    }
 321
 322    g_free(buf);
 323
 324    if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 325        return task.ret < 0 ? task.ret : -EIO;
 326    }
 327
 328    return 0;
 329}
 330
 331static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 332{
 333    NFSClient *client = bs->opaque;
 334    NFSRPC task;
 335
 336    nfs_co_init_task(bs, &task);
 337
 338    if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 339                        &task) != 0) {
 340        return -ENOMEM;
 341    }
 342
 343    nfs_set_events(client);
 344    while (!task.complete) {
 345        qemu_coroutine_yield();
 346    }
 347
 348    return task.ret;
 349}
 350
 351static QemuOptsList runtime_opts = {
 352    .name = "nfs",
 353    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 354    .desc = {
 355        {
 356            .name = "path",
 357            .type = QEMU_OPT_STRING,
 358            .help = "Path of the image on the host",
 359        },
 360        {
 361            .name = "user",
 362            .type = QEMU_OPT_NUMBER,
 363            .help = "UID value to use when talking to the server",
 364        },
 365        {
 366            .name = "group",
 367            .type = QEMU_OPT_NUMBER,
 368            .help = "GID value to use when talking to the server",
 369        },
 370        {
 371            .name = "tcp-syn-count",
 372            .type = QEMU_OPT_NUMBER,
 373            .help = "Number of SYNs to send during the session establish",
 374        },
 375        {
 376            .name = "readahead-size",
 377            .type = QEMU_OPT_NUMBER,
 378            .help = "Set the readahead size in bytes",
 379        },
 380        {
 381            .name = "page-cache-size",
 382            .type = QEMU_OPT_NUMBER,
 383            .help = "Set the pagecache size in bytes",
 384        },
 385        {
 386            .name = "debug",
 387            .type = QEMU_OPT_NUMBER,
 388            .help = "Set the NFS debug level (max 2)",
 389        },
 390        { /* end of list */ }
 391    },
 392};
 393
 394static void nfs_detach_aio_context(BlockDriverState *bs)
 395{
 396    NFSClient *client = bs->opaque;
 397
 398    aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 399                       false, NULL, NULL, NULL);
 400    client->events = 0;
 401}
 402
 403static void nfs_attach_aio_context(BlockDriverState *bs,
 404                                   AioContext *new_context)
 405{
 406    NFSClient *client = bs->opaque;
 407
 408    client->aio_context = new_context;
 409    nfs_set_events(client);
 410}
 411
 412static void nfs_client_close(NFSClient *client)
 413{
 414    if (client->context) {
 415        if (client->fh) {
 416            nfs_close(client->context, client->fh);
 417        }
 418        aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 419                           false, NULL, NULL, NULL);
 420        nfs_destroy_context(client->context);
 421    }
 422    memset(client, 0, sizeof(NFSClient));
 423}
 424
 425static void nfs_file_close(BlockDriverState *bs)
 426{
 427    NFSClient *client = bs->opaque;
 428    nfs_client_close(client);
 429}
 430
 431static NFSServer *nfs_config(QDict *options, Error **errp)
 432{
 433    NFSServer *server = NULL;
 434    QDict *addr = NULL;
 435    QObject *crumpled_addr = NULL;
 436    Visitor *iv = NULL;
 437    Error *local_error = NULL;
 438
 439    qdict_extract_subqdict(options, &addr, "server.");
 440    if (!qdict_size(addr)) {
 441        error_setg(errp, "NFS server address missing");
 442        goto out;
 443    }
 444
 445    crumpled_addr = qdict_crumple(addr, errp);
 446    if (!crumpled_addr) {
 447        goto out;
 448    }
 449
 450    iv = qobject_input_visitor_new(crumpled_addr, true);
 451    visit_type_NFSServer(iv, NULL, &server, &local_error);
 452    if (local_error) {
 453        error_propagate(errp, local_error);
 454        goto out;
 455    }
 456
 457out:
 458    QDECREF(addr);
 459    qobject_decref(crumpled_addr);
 460    visit_free(iv);
 461    return server;
 462}
 463
 464
 465static int64_t nfs_client_open(NFSClient *client, QDict *options,
 466                               int flags, Error **errp, int open_flags)
 467{
 468    int ret = -EINVAL;
 469    QemuOpts *opts = NULL;
 470    Error *local_err = NULL;
 471    struct stat st;
 472    char *file = NULL, *strp = NULL;
 473
 474    opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 475    qemu_opts_absorb_qdict(opts, options, &local_err);
 476    if (local_err) {
 477        error_propagate(errp, local_err);
 478        ret = -EINVAL;
 479        goto fail;
 480    }
 481
 482    client->path = g_strdup(qemu_opt_get(opts, "path"));
 483    if (!client->path) {
 484        ret = -EINVAL;
 485        error_setg(errp, "No path was specified");
 486        goto fail;
 487    }
 488
 489    strp = strrchr(client->path, '/');
 490    if (strp == NULL) {
 491        error_setg(errp, "Invalid URL specified");
 492        goto fail;
 493    }
 494    file = g_strdup(strp);
 495    *strp = 0;
 496
 497    /* Pop the config into our state object, Exit if invalid */
 498    client->server = nfs_config(options, errp);
 499    if (!client->server) {
 500        ret = -EINVAL;
 501        goto fail;
 502    }
 503
 504    client->context = nfs_init_context();
 505    if (client->context == NULL) {
 506        error_setg(errp, "Failed to init NFS context");
 507        goto fail;
 508    }
 509
 510    if (qemu_opt_get(opts, "user")) {
 511        client->uid = qemu_opt_get_number(opts, "user", 0);
 512        nfs_set_uid(client->context, client->uid);
 513    }
 514
 515    if (qemu_opt_get(opts, "group")) {
 516        client->gid = qemu_opt_get_number(opts, "group", 0);
 517        nfs_set_gid(client->context, client->gid);
 518    }
 519
 520    if (qemu_opt_get(opts, "tcp-syn-count")) {
 521        client->tcp_syncnt = qemu_opt_get_number(opts, "tcp-syn-count", 0);
 522        nfs_set_tcp_syncnt(client->context, client->tcp_syncnt);
 523    }
 524
 525#ifdef LIBNFS_FEATURE_READAHEAD
 526    if (qemu_opt_get(opts, "readahead-size")) {
 527        if (open_flags & BDRV_O_NOCACHE) {
 528            error_setg(errp, "Cannot enable NFS readahead "
 529                             "if cache.direct = on");
 530            goto fail;
 531        }
 532        client->readahead = qemu_opt_get_number(opts, "readahead-size", 0);
 533        if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) {
 534            error_report("NFS Warning: Truncating NFS readahead "
 535                         "size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
 536            client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE;
 537        }
 538        nfs_set_readahead(client->context, client->readahead);
 539#ifdef LIBNFS_FEATURE_PAGECACHE
 540        nfs_set_pagecache_ttl(client->context, 0);
 541#endif
 542        client->cache_used = true;
 543    }
 544#endif
 545
 546#ifdef LIBNFS_FEATURE_PAGECACHE
 547    if (qemu_opt_get(opts, "page-cache-size")) {
 548        if (open_flags & BDRV_O_NOCACHE) {
 549            error_setg(errp, "Cannot enable NFS pagecache "
 550                             "if cache.direct = on");
 551            goto fail;
 552        }
 553        client->pagecache = qemu_opt_get_number(opts, "page-cache-size", 0);
 554        if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 555            error_report("NFS Warning: Truncating NFS pagecache "
 556                         "size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
 557            client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE;
 558        }
 559        nfs_set_pagecache(client->context, client->pagecache);
 560        nfs_set_pagecache_ttl(client->context, 0);
 561        client->cache_used = true;
 562    }
 563#endif
 564
 565#ifdef LIBNFS_FEATURE_DEBUG
 566    if (qemu_opt_get(opts, "debug")) {
 567        client->debug = qemu_opt_get_number(opts, "debug", 0);
 568        /* limit the maximum debug level to avoid potential flooding
 569         * of our log files. */
 570        if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) {
 571            error_report("NFS Warning: Limiting NFS debug level "
 572                         "to %d", QEMU_NFS_MAX_DEBUG_LEVEL);
 573            client->debug = QEMU_NFS_MAX_DEBUG_LEVEL;
 574        }
 575        nfs_set_debug(client->context, client->debug);
 576    }
 577#endif
 578
 579    ret = nfs_mount(client->context, client->server->host, client->path);
 580    if (ret < 0) {
 581        error_setg(errp, "Failed to mount nfs share: %s",
 582                   nfs_get_error(client->context));
 583        goto fail;
 584    }
 585
 586    if (flags & O_CREAT) {
 587        ret = nfs_creat(client->context, file, 0600, &client->fh);
 588        if (ret < 0) {
 589            error_setg(errp, "Failed to create file: %s",
 590                       nfs_get_error(client->context));
 591            goto fail;
 592        }
 593    } else {
 594        ret = nfs_open(client->context, file, flags, &client->fh);
 595        if (ret < 0) {
 596            error_setg(errp, "Failed to open file : %s",
 597                       nfs_get_error(client->context));
 598            goto fail;
 599        }
 600    }
 601
 602    ret = nfs_fstat(client->context, client->fh, &st);
 603    if (ret < 0) {
 604        error_setg(errp, "Failed to fstat file: %s",
 605                   nfs_get_error(client->context));
 606        goto fail;
 607    }
 608
 609    ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 610    client->st_blocks = st.st_blocks;
 611    client->has_zero_init = S_ISREG(st.st_mode);
 612    *strp = '/';
 613    goto out;
 614
 615fail:
 616    nfs_client_close(client);
 617out:
 618    qemu_opts_del(opts);
 619    g_free(file);
 620    return ret;
 621}
 622
 623static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 624                         Error **errp) {
 625    NFSClient *client = bs->opaque;
 626    int64_t ret;
 627
 628    client->aio_context = bdrv_get_aio_context(bs);
 629
 630    ret = nfs_client_open(client, options,
 631                          (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 632                          errp, bs->open_flags);
 633    if (ret < 0) {
 634        return ret;
 635    }
 636    bs->total_sectors = ret;
 637    ret = 0;
 638    return ret;
 639}
 640
 641static QemuOptsList nfs_create_opts = {
 642    .name = "nfs-create-opts",
 643    .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 644    .desc = {
 645        {
 646            .name = BLOCK_OPT_SIZE,
 647            .type = QEMU_OPT_SIZE,
 648            .help = "Virtual disk size"
 649        },
 650        { /* end of list */ }
 651    }
 652};
 653
 654static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
 655{
 656    int ret = 0;
 657    int64_t total_size = 0;
 658    NFSClient *client = g_new0(NFSClient, 1);
 659    QDict *options = NULL;
 660
 661    client->aio_context = qemu_get_aio_context();
 662
 663    /* Read out options */
 664    total_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    ret = nfs_client_open(client, options, O_CREAT, errp, 0);
 674    if (ret < 0) {
 675        goto out;
 676    }
 677    ret = nfs_ftruncate(client->context, client->fh, total_size);
 678    nfs_client_close(client);
 679out:
 680    QDECREF(options);
 681    g_free(client);
 682    return ret;
 683}
 684
 685static int nfs_has_zero_init(BlockDriverState *bs)
 686{
 687    NFSClient *client = bs->opaque;
 688    return client->has_zero_init;
 689}
 690
 691static void
 692nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 693                               void *private_data)
 694{
 695    NFSRPC *task = private_data;
 696    task->ret = ret;
 697    if (task->ret == 0) {
 698        memcpy(task->st, data, sizeof(struct stat));
 699    }
 700    if (task->ret < 0) {
 701        error_report("NFS Error: %s", nfs_get_error(nfs));
 702    }
 703    task->complete = 1;
 704    bdrv_wakeup(task->bs);
 705}
 706
 707static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 708{
 709    NFSClient *client = bs->opaque;
 710    NFSRPC task = {0};
 711    struct stat st;
 712
 713    if (bdrv_is_read_only(bs) &&
 714        !(bs->open_flags & BDRV_O_NOCACHE)) {
 715        return client->st_blocks * 512;
 716    }
 717
 718    task.bs = bs;
 719    task.st = &st;
 720    if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 721                        &task) != 0) {
 722        return -ENOMEM;
 723    }
 724
 725    nfs_set_events(client);
 726    BDRV_POLL_WHILE(bs, !task.complete);
 727
 728    return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 729}
 730
 731static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 732{
 733    NFSClient *client = bs->opaque;
 734    return nfs_ftruncate(client->context, client->fh, offset);
 735}
 736
 737/* Note that this will not re-establish a connection with the NFS server
 738 * - it is effectively a NOP.  */
 739static int nfs_reopen_prepare(BDRVReopenState *state,
 740                              BlockReopenQueue *queue, Error **errp)
 741{
 742    NFSClient *client = state->bs->opaque;
 743    struct stat st;
 744    int ret = 0;
 745
 746    if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 747        error_setg(errp, "Cannot open a read-only mount as read-write");
 748        return -EACCES;
 749    }
 750
 751    if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 752        error_setg(errp, "Cannot disable cache if libnfs readahead or"
 753                         " pagecache is enabled");
 754        return -EINVAL;
 755    }
 756
 757    /* Update cache for read-only reopens */
 758    if (!(state->flags & BDRV_O_RDWR)) {
 759        ret = nfs_fstat(client->context, client->fh, &st);
 760        if (ret < 0) {
 761            error_setg(errp, "Failed to fstat file: %s",
 762                       nfs_get_error(client->context));
 763            return ret;
 764        }
 765        client->st_blocks = st.st_blocks;
 766    }
 767
 768    return 0;
 769}
 770
 771static void nfs_refresh_filename(BlockDriverState *bs, QDict *options)
 772{
 773    NFSClient *client = bs->opaque;
 774    QDict *opts = qdict_new();
 775    QObject *server_qdict;
 776    Visitor *ov;
 777
 778    qdict_put(opts, "driver", qstring_from_str("nfs"));
 779
 780    if (client->uid && !client->gid) {
 781        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 782                 "nfs://%s%s?uid=%" PRId64, client->server->host, client->path,
 783                 client->uid);
 784    } else if (!client->uid && client->gid) {
 785        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 786                 "nfs://%s%s?gid=%" PRId64, client->server->host, client->path,
 787                 client->gid);
 788    } else if (client->uid && client->gid) {
 789        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 790                 "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64,
 791                 client->server->host, client->path, client->uid, client->gid);
 792    } else {
 793        snprintf(bs->exact_filename, sizeof(bs->exact_filename),
 794                 "nfs://%s%s", client->server->host, client->path);
 795    }
 796
 797    ov = qobject_output_visitor_new(&server_qdict);
 798    visit_type_NFSServer(ov, NULL, &client->server, &error_abort);
 799    visit_complete(ov, &server_qdict);
 800    assert(qobject_type(server_qdict) == QTYPE_QDICT);
 801
 802    qdict_put_obj(opts, "server", server_qdict);
 803    qdict_put(opts, "path", qstring_from_str(client->path));
 804
 805    if (client->uid) {
 806        qdict_put(opts, "user", qint_from_int(client->uid));
 807    }
 808    if (client->gid) {
 809        qdict_put(opts, "group", qint_from_int(client->gid));
 810    }
 811    if (client->tcp_syncnt) {
 812        qdict_put(opts, "tcp-syn-cnt",
 813                  qint_from_int(client->tcp_syncnt));
 814    }
 815    if (client->readahead) {
 816        qdict_put(opts, "readahead-size",
 817                  qint_from_int(client->readahead));
 818    }
 819    if (client->pagecache) {
 820        qdict_put(opts, "page-cache-size",
 821                  qint_from_int(client->pagecache));
 822    }
 823    if (client->debug) {
 824        qdict_put(opts, "debug", qint_from_int(client->debug));
 825    }
 826
 827    visit_free(ov);
 828    qdict_flatten(opts);
 829    bs->full_open_options = opts;
 830}
 831
 832#ifdef LIBNFS_FEATURE_PAGECACHE
 833static void nfs_invalidate_cache(BlockDriverState *bs,
 834                                 Error **errp)
 835{
 836    NFSClient *client = bs->opaque;
 837    nfs_pagecache_invalidate(client->context, client->fh);
 838}
 839#endif
 840
 841static BlockDriver bdrv_nfs = {
 842    .format_name                    = "nfs",
 843    .protocol_name                  = "nfs",
 844
 845    .instance_size                  = sizeof(NFSClient),
 846    .bdrv_parse_filename            = nfs_parse_filename,
 847    .create_opts                    = &nfs_create_opts,
 848
 849    .bdrv_has_zero_init             = nfs_has_zero_init,
 850    .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 851    .bdrv_truncate                  = nfs_file_truncate,
 852
 853    .bdrv_file_open                 = nfs_file_open,
 854    .bdrv_close                     = nfs_file_close,
 855    .bdrv_create                    = nfs_file_create,
 856    .bdrv_reopen_prepare            = nfs_reopen_prepare,
 857
 858    .bdrv_co_readv                  = nfs_co_readv,
 859    .bdrv_co_writev                 = nfs_co_writev,
 860    .bdrv_co_flush_to_disk          = nfs_co_flush,
 861
 862    .bdrv_detach_aio_context        = nfs_detach_aio_context,
 863    .bdrv_attach_aio_context        = nfs_attach_aio_context,
 864    .bdrv_refresh_filename          = nfs_refresh_filename,
 865
 866#ifdef LIBNFS_FEATURE_PAGECACHE
 867    .bdrv_invalidate_cache          = nfs_invalidate_cache,
 868#endif
 869};
 870
 871static void nfs_block_init(void)
 872{
 873    bdrv_register(&bdrv_nfs);
 874}
 875
 876block_init(nfs_block_init);
 877