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 <nfsc/libnfs.h>
  39
  40 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  41 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
  42 #define QEMU_NFS_MAX_DEBUG_LEVEL 2
  43
  44 typedef struct NFSClient {
  45     struct nfs_context *context;
  46     struct nfsfh *fh;
  47     int events;
  48     bool has_zero_init;
  49     AioContext *aio_context;
  50     blkcnt_t st_blocks;
  51     bool cache_used;
  52 } NFSClient;
  53
  54 typedef struct NFSRPC {
  55     BlockDriverState *bs;
  56     int ret;
  57     int complete;
  58     QEMUIOVector *iov;
  59     struct stat *st;
  60     Coroutine *co;
  61     NFSClient *client;
  62 } NFSRPC;
  63
  64 static void nfs_process_read(void *arg);
  65 static void nfs_process_write(void *arg);
  66
  67 static void nfs_set_events(NFSClient *client)
  68 {
  69     int ev = nfs_which_events(client->context);
  70     if (ev != client->events) {
  71         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
  72                            false,
  73                            (ev & POLLIN) ? nfs_process_read : NULL,
  74                            (ev & POLLOUT) ? nfs_process_write : NULL, client);
  75
  76     }
  77     client->events = ev;
  78 }
  79
  80 static void nfs_process_read(void *arg)
  81 {
  82     NFSClient *client = arg;
  83     nfs_service(client->context, POLLIN);
  84     nfs_set_events(client);
  85 }
  86
  87 static void nfs_process_write(void *arg)
  88 {
  89     NFSClient *client = arg;
  90     nfs_service(client->context, POLLOUT);
  91     nfs_set_events(client);
  92 }
  93
  94 static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
  95 {
  96     *task = (NFSRPC) {
  97         .co             = qemu_coroutine_self(),
  98         .bs             = bs,
  99         .client         = bs->opaque,
 100     };
 101 }
 102
 103 static void nfs_co_generic_bh_cb(void *opaque)
 104 {
 105     NFSRPC *task = opaque;
 106     task->complete = 1;
 107     qemu_coroutine_enter(task->co);
 108 }
 109
 110 static void
 111 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 112                   void *private_data)
 113 {
 114     NFSRPC *task = private_data;
 115     task->ret = ret;
 116     assert(!task->st);
 117     if (task->ret > 0 && task->iov) {
 118         if (task->ret <= task->iov->size) {
 119             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 120         } else {
 121             task->ret = -EIO;
 122         }
 123     }
 124     if (task->ret < 0) {
 125         error_report("NFS Error: %s", nfs_get_error(nfs));
 126     }
 127     aio_bh_schedule_oneshot(task->client->aio_context,
 128                             nfs_co_generic_bh_cb, task);
 129 }
 130
 131 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 132                                      int64_t sector_num, int nb_sectors,
 133                                      QEMUIOVector *iov)
 134 {
 135     NFSClient *client = bs->opaque;
 136     NFSRPC task;
 137
 138     nfs_co_init_task(bs, &task);
 139     task.iov = iov;
 140
 141     if (nfs_pread_async(client->context, client->fh,
 142                         sector_num * BDRV_SECTOR_SIZE,
 143                         nb_sectors * BDRV_SECTOR_SIZE,
 144                         nfs_co_generic_cb, &task) != 0) {
 145         return -ENOMEM;
 146     }
 147
 148     nfs_set_events(client);
 149     while (!task.complete) {
 150         qemu_coroutine_yield();
 151     }
 152
 153     if (task.ret < 0) {
 154         return task.ret;
 155     }
 156
 157     /* zero pad short reads */
 158     if (task.ret < iov->size) {
 159         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 160     }
 161
 162     return 0;
 163 }
 164
 165 static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 166                                         int64_t sector_num, int nb_sectors,
 167                                         QEMUIOVector *iov)
 168 {
 169     NFSClient *client = bs->opaque;
 170     NFSRPC task;
 171     char *buf = NULL;
 172
 173     nfs_co_init_task(bs, &task);
 174
 175     buf = g_try_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 176     if (nb_sectors && buf == NULL) {
 177         return -ENOMEM;
 178     }
 179
 180     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 181
 182     if (nfs_pwrite_async(client->context, client->fh,
 183                          sector_num * BDRV_SECTOR_SIZE,
 184                          nb_sectors * BDRV_SECTOR_SIZE,
 185                          buf, nfs_co_generic_cb, &task) != 0) {
 186         g_free(buf);
 187         return -ENOMEM;
 188     }
 189
 190     nfs_set_events(client);
 191     while (!task.complete) {
 192         qemu_coroutine_yield();
 193     }
 194
 195     g_free(buf);
 196
 197     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 198         return task.ret < 0 ? task.ret : -EIO;
 199     }
 200
 201     return 0;
 202 }
 203
 204 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 205 {
 206     NFSClient *client = bs->opaque;
 207     NFSRPC task;
 208
 209     nfs_co_init_task(bs, &task);
 210
 211     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 212                         &task) != 0) {
 213         return -ENOMEM;
 214     }
 215
 216     nfs_set_events(client);
 217     while (!task.complete) {
 218         qemu_coroutine_yield();
 219     }
 220
 221     return task.ret;
 222 }
 223
 224 /* TODO Convert to fine grained options */
 225 static QemuOptsList runtime_opts = {
 226     .name = "nfs",
 227     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 228     .desc = {
 229         {
 230             .name = "filename",
 231             .type = QEMU_OPT_STRING,
 232             .help = "URL to the NFS file",
 233         },
 234         { /* end of list */ }
 235     },
 236 };
 237
 238 static void nfs_detach_aio_context(BlockDriverState *bs)
 239 {
 240     NFSClient *client = bs->opaque;
 241
 242     aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 243                        false, NULL, NULL, NULL);
 244     client->events = 0;
 245 }
 246
 247 static void nfs_attach_aio_context(BlockDriverState *bs,
 248                                    AioContext *new_context)
 249 {
 250     NFSClient *client = bs->opaque;
 251
 252     client->aio_context = new_context;
 253     nfs_set_events(client);
 254 }
 255
 256 static void nfs_client_close(NFSClient *client)
 257 {
 258     if (client->context) {
 259         if (client->fh) {
 260             nfs_close(client->context, client->fh);
 261         }
 262         aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context),
 263                            false, NULL, NULL, NULL);
 264         nfs_destroy_context(client->context);
 265     }
 266     memset(client, 0, sizeof(NFSClient));
 267 }
 268
 269 static void nfs_file_close(BlockDriverState *bs)
 270 {
 271     NFSClient *client = bs->opaque;
 272     nfs_client_close(client);
 273 }
 274
 275 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 276                                int flags, Error **errp, int open_flags)
 277 {
 278     int ret = -EINVAL, i;
 279     struct stat st;
 280     URI *uri;
 281     QueryParams *qp = NULL;
 282     char *file = NULL, *strp = NULL;
 283
 284     uri = uri_parse(filename);
 285     if (!uri) {
 286         error_setg(errp, "Invalid URL specified");
 287         goto fail;
 288     }
 289     if (!uri->server) {
 290         error_setg(errp, "Invalid URL specified");
 291         goto fail;
 292     }
 293     strp = strrchr(uri->path, '/');
 294     if (strp == NULL) {
 295         error_setg(errp, "Invalid URL specified");
 296         goto fail;
 297     }
 298     file = g_strdup(strp);
 299     *strp = 0;
 300
 301     client->context = nfs_init_context();
 302     if (client->context == NULL) {
 303         error_setg(errp, "Failed to init NFS context");
 304         goto fail;
 305     }
 306
 307     qp = query_params_parse(uri->query);
 308     for (i = 0; i < qp->n; i++) {
 309         unsigned long long val;
 310         if (!qp->p[i].value) {
 311             error_setg(errp, "Value for NFS parameter expected: %s",
 312                        qp->p[i].name);
 313             goto fail;
 314         }
 315         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 316             error_setg(errp, "Illegal value for NFS parameter: %s",
 317                        qp->p[i].name);
 318             goto fail;
 319         }
 320         if (!strcmp(qp->p[i].name, "uid")) {
 321             nfs_set_uid(client->context, val);
 322         } else if (!strcmp(qp->p[i].name, "gid")) {
 323             nfs_set_gid(client->context, val);
 324         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 325             nfs_set_tcp_syncnt(client->context, val);
 326 #ifdef LIBNFS_FEATURE_READAHEAD
 327         } else if (!strcmp(qp->p[i].name, "readahead")) {
 328             if (open_flags & BDRV_O_NOCACHE) {
 329                 error_setg(errp, "Cannot enable NFS readahead "
 330                                  "if cache.direct = on");
 331                 goto fail;
 332             }
 333             if (val > QEMU_NFS_MAX_READAHEAD_SIZE) {
 334                 error_report("NFS Warning: Truncating NFS readahead"
 335                              " size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
 336                 val = QEMU_NFS_MAX_READAHEAD_SIZE;
 337             }
 338             nfs_set_readahead(client->context, val);
 339 #ifdef LIBNFS_FEATURE_PAGECACHE
 340             nfs_set_pagecache_ttl(client->context, 0);
 341 #endif
 342             client->cache_used = true;
 343 #endif
 344 #ifdef LIBNFS_FEATURE_PAGECACHE
 345             nfs_set_pagecache_ttl(client->context, 0);
 346         } else if (!strcmp(qp->p[i].name, "pagecache")) {
 347             if (open_flags & BDRV_O_NOCACHE) {
 348                 error_setg(errp, "Cannot enable NFS pagecache "
 349                                  "if cache.direct = on");
 350                 goto fail;
 351             }
 352             if (val > QEMU_NFS_MAX_PAGECACHE_SIZE) {
 353                 error_report("NFS Warning: Truncating NFS pagecache"
 354                              " size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
 355                 val = QEMU_NFS_MAX_PAGECACHE_SIZE;
 356             }
 357             nfs_set_pagecache(client->context, val);
 358             nfs_set_pagecache_ttl(client->context, 0);
 359             client->cache_used = true;
 360 #endif
 361 #ifdef LIBNFS_FEATURE_DEBUG
 362         } else if (!strcmp(qp->p[i].name, "debug")) {
 363             /* limit the maximum debug level to avoid potential flooding
 364              * of our log files. */
 365             if (val > QEMU_NFS_MAX_DEBUG_LEVEL) {
 366                 error_report("NFS Warning: Limiting NFS debug level"
 367                              " to %d", QEMU_NFS_MAX_DEBUG_LEVEL);
 368                 val = QEMU_NFS_MAX_DEBUG_LEVEL;
 369             }
 370             nfs_set_debug(client->context, val);
 371 #endif
 372         } else {
 373             error_setg(errp, "Unknown NFS parameter name: %s",
 374                        qp->p[i].name);
 375             goto fail;
 376         }
 377     }
 378
 379     ret = nfs_mount(client->context, uri->server, uri->path);
 380     if (ret < 0) {
 381         error_setg(errp, "Failed to mount nfs share: %s",
 382                    nfs_get_error(client->context));
 383         goto fail;
 384     }
 385
 386     if (flags & O_CREAT) {
 387         ret = nfs_creat(client->context, file, 0600, &client->fh);
 388         if (ret < 0) {
 389             error_setg(errp, "Failed to create file: %s",
 390                        nfs_get_error(client->context));
 391             goto fail;
 392         }
 393     } else {
 394         ret = nfs_open(client->context, file, flags, &client->fh);
 395         if (ret < 0) {
 396             error_setg(errp, "Failed to open file : %s",
 397                        nfs_get_error(client->context));
 398             goto fail;
 399         }
 400     }
 401
 402     ret = nfs_fstat(client->context, client->fh, &st);
 403     if (ret < 0) {
 404         error_setg(errp, "Failed to fstat file: %s",
 405                    nfs_get_error(client->context));
 406         goto fail;
 407     }
 408
 409     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 410     client->st_blocks = st.st_blocks;
 411     client->has_zero_init = S_ISREG(st.st_mode);
 412     goto out;
 413 fail:
 414     nfs_client_close(client);
 415 out:
 416     if (qp) {
 417         query_params_free(qp);
 418     }
 419     uri_free(uri);
 420     g_free(file);
 421     return ret;
 422 }
 423
 424 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 425                          Error **errp) {
 426     NFSClient *client = bs->opaque;
 427     int64_t ret;
 428     QemuOpts *opts;
 429     Error *local_err = NULL;
 430
 431     client->aio_context = bdrv_get_aio_context(bs);
 432
 433     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 434     qemu_opts_absorb_qdict(opts, options, &local_err);
 435     if (local_err) {
 436         error_propagate(errp, local_err);
 437         ret = -EINVAL;
 438         goto out;
 439     }
 440     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 441                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 442                           errp, bs->open_flags);
 443     if (ret < 0) {
 444         goto out;
 445     }
 446     bs->total_sectors = ret;
 447     ret = 0;
 448 out:
 449     qemu_opts_del(opts);
 450     return ret;
 451 }
 452
 453 static QemuOptsList nfs_create_opts = {
 454     .name = "nfs-create-opts",
 455     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 456     .desc = {
 457         {
 458             .name = BLOCK_OPT_SIZE,
 459             .type = QEMU_OPT_SIZE,
 460             .help = "Virtual disk size"
 461         },
 462         { /* end of list */ }
 463     }
 464 };
 465
 466 static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
 467 {
 468     int ret = 0;
 469     int64_t total_size = 0;
 470     NFSClient *client = g_new0(NFSClient, 1);
 471
 472     client->aio_context = qemu_get_aio_context();
 473
 474     /* Read out options */
 475     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 476                           BDRV_SECTOR_SIZE);
 477
 478     ret = nfs_client_open(client, url, O_CREAT, errp, 0);
 479     if (ret < 0) {
 480         goto out;
 481     }
 482     ret = nfs_ftruncate(client->context, client->fh, total_size);
 483     nfs_client_close(client);
 484 out:
 485     g_free(client);
 486     return ret;
 487 }
 488
 489 static int nfs_has_zero_init(BlockDriverState *bs)
 490 {
 491     NFSClient *client = bs->opaque;
 492     return client->has_zero_init;
 493 }
 494
 495 static void
 496 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
 497                                void *private_data)
 498 {
 499     NFSRPC *task = private_data;
 500     task->ret = ret;
 501     if (task->ret == 0) {
 502         memcpy(task->st, data, sizeof(struct stat));
 503     }
 504     if (task->ret < 0) {
 505         error_report("NFS Error: %s", nfs_get_error(nfs));
 506     }
 507     task->complete = 1;
 508     bdrv_wakeup(task->bs);
 509 }
 510
 511 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 512 {
 513     NFSClient *client = bs->opaque;
 514     NFSRPC task = {0};
 515     struct stat st;
 516
 517     if (bdrv_is_read_only(bs) &&
 518         !(bs->open_flags & BDRV_O_NOCACHE)) {
 519         return client->st_blocks * 512;
 520     }
 521
 522     task.bs = bs;
 523     task.st = &st;
 524     if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb,
 525                         &task) != 0) {
 526         return -ENOMEM;
 527     }
 528
 529     nfs_set_events(client);
 530     BDRV_POLL_WHILE(bs, !task.complete);
 531
 532     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 533 }
 534
 535 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 536 {
 537     NFSClient *client = bs->opaque;
 538     return nfs_ftruncate(client->context, client->fh, offset);
 539 }
 540
 541 /* Note that this will not re-establish a connection with the NFS server
 542  * - it is effectively a NOP.  */
 543 static int nfs_reopen_prepare(BDRVReopenState *state,
 544                               BlockReopenQueue *queue, Error **errp)
 545 {
 546     NFSClient *client = state->bs->opaque;
 547     struct stat st;
 548     int ret = 0;
 549
 550     if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) {
 551         error_setg(errp, "Cannot open a read-only mount as read-write");
 552         return -EACCES;
 553     }
 554
 555     if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
 556         error_setg(errp, "Cannot disable cache if libnfs readahead or"
 557                          " pagecache is enabled");
 558         return -EINVAL;
 559     }
 560
 561     /* Update cache for read-only reopens */
 562     if (!(state->flags & BDRV_O_RDWR)) {
 563         ret = nfs_fstat(client->context, client->fh, &st);
 564         if (ret < 0) {
 565             error_setg(errp, "Failed to fstat file: %s",
 566                        nfs_get_error(client->context));
 567             return ret;
 568         }
 569         client->st_blocks = st.st_blocks;
 570     }
 571
 572     return 0;
 573 }
 574
 575 #ifdef LIBNFS_FEATURE_PAGECACHE
 576 static void nfs_invalidate_cache(BlockDriverState *bs,
 577                                  Error **errp)
 578 {
 579     NFSClient *client = bs->opaque;
 580     nfs_pagecache_invalidate(client->context, client->fh);
 581 }
 582 #endif
 583
 584 static BlockDriver bdrv_nfs = {
 585     .format_name                    = "nfs",
 586     .protocol_name                  = "nfs",
 587
 588     .instance_size                  = sizeof(NFSClient),
 589     .bdrv_needs_filename            = true,
 590     .create_opts                    = &nfs_create_opts,
 591
 592     .bdrv_has_zero_init             = nfs_has_zero_init,
 593     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 594     .bdrv_truncate                  = nfs_file_truncate,
 595
 596     .bdrv_file_open                 = nfs_file_open,
 597     .bdrv_close                     = nfs_file_close,
 598     .bdrv_create                    = nfs_file_create,
 599     .bdrv_reopen_prepare            = nfs_reopen_prepare,
 600
 601     .bdrv_co_readv                  = nfs_co_readv,
 602     .bdrv_co_writev                 = nfs_co_writev,
 603     .bdrv_co_flush_to_disk          = nfs_co_flush,
 604
 605     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 606     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 607
 608 #ifdef LIBNFS_FEATURE_PAGECACHE
 609     .bdrv_invalidate_cache          = nfs_invalidate_cache,
 610 #endif
 611 };
 612
 613 static void nfs_block_init(void)
 614 {
 615     bdrv_register(&bdrv_nfs);
 616 }
 617
 618 block_init(nfs_block_init);