block/nfs.c

   1 /*
   2  * QEMU Block driver for native access to files on NFS shares
   3  *
   4  * Copyright (c) 2014 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 "config-host.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 "block/block_int.h"
  32 #include "trace.h"
  33 #include "qemu/iov.h"
  34 #include "qemu/uri.h"
  35 #include "sysemu/sysemu.h"
  36 #include <nfsc/libnfs.h>
  37
  38 #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
  39
  40 typedef struct NFSClient {
  41     struct nfs_context *context;
  42     struct nfsfh *fh;
  43     int events;
  44     bool has_zero_init;
  45     AioContext *aio_context;
  46 } NFSClient;
  47
  48 typedef struct NFSRPC {
  49     int ret;
  50     int complete;
  51     QEMUIOVector *iov;
  52     struct stat *st;
  53     Coroutine *co;
  54     QEMUBH *bh;
  55     NFSClient *client;
  56 } NFSRPC;
  57
  58 static void nfs_process_read(void *arg);
  59 static void nfs_process_write(void *arg);
  60
  61 static void nfs_set_events(NFSClient *client)
  62 {
  63     int ev = nfs_which_events(client->context);
  64     if (ev != client->events) {
  65         aio_set_fd_handler(client->aio_context,
  66                            nfs_get_fd(client->context),
  67                            (ev & POLLIN) ? nfs_process_read : NULL,
  68                            (ev & POLLOUT) ? nfs_process_write : NULL,
  69                            client);
  70
  71     }
  72     client->events = ev;
  73 }
  74
  75 static void nfs_process_read(void *arg)
  76 {
  77     NFSClient *client = arg;
  78     nfs_service(client->context, POLLIN);
  79     nfs_set_events(client);
  80 }
  81
  82 static void nfs_process_write(void *arg)
  83 {
  84     NFSClient *client = arg;
  85     nfs_service(client->context, POLLOUT);
  86     nfs_set_events(client);
  87 }
  88
  89 static void nfs_co_init_task(NFSClient *client, NFSRPC *task)
  90 {
  91     *task = (NFSRPC) {
  92         .co             = qemu_coroutine_self(),
  93         .client         = client,
  94     };
  95 }
  96
  97 static void nfs_co_generic_bh_cb(void *opaque)
  98 {
  99     NFSRPC *task = opaque;
 100     task->complete = 1;
 101     qemu_bh_delete(task->bh);
 102     qemu_coroutine_enter(task->co, NULL);
 103 }
 104
 105 static void
 106 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 107                   void *private_data)
 108 {
 109     NFSRPC *task = private_data;
 110     task->ret = ret;
 111     if (task->ret > 0 && task->iov) {
 112         if (task->ret <= task->iov->size) {
 113             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 114         } else {
 115             task->ret = -EIO;
 116         }
 117     }
 118     if (task->ret == 0 && task->st) {
 119         memcpy(task->st, data, sizeof(struct stat));
 120     }
 121     if (task->ret < 0) {
 122         error_report("NFS Error: %s", nfs_get_error(nfs));
 123     }
 124     if (task->co) {
 125         task->bh = aio_bh_new(task->client->aio_context,
 126                               nfs_co_generic_bh_cb, task);
 127         qemu_bh_schedule(task->bh);
 128     } else {
 129         task->complete = 1;
 130     }
 131 }
 132
 133 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 134                                      int64_t sector_num, int nb_sectors,
 135                                      QEMUIOVector *iov)
 136 {
 137     NFSClient *client = bs->opaque;
 138     NFSRPC task;
 139
 140     nfs_co_init_task(client, &task);
 141     task.iov = iov;
 142
 143     if (nfs_pread_async(client->context, client->fh,
 144                         sector_num * BDRV_SECTOR_SIZE,
 145                         nb_sectors * BDRV_SECTOR_SIZE,
 146                         nfs_co_generic_cb, &task) != 0) {
 147         return -ENOMEM;
 148     }
 149
 150     while (!task.complete) {
 151         nfs_set_events(client);
 152         qemu_coroutine_yield();
 153     }
 154
 155     if (task.ret < 0) {
 156         return task.ret;
 157     }
 158
 159     /* zero pad short reads */
 160     if (task.ret < iov->size) {
 161         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 162     }
 163
 164     return 0;
 165 }
 166
 167 static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 168                                         int64_t sector_num, int nb_sectors,
 169                                         QEMUIOVector *iov)
 170 {
 171     NFSClient *client = bs->opaque;
 172     NFSRPC task;
 173     char *buf = NULL;
 174
 175     nfs_co_init_task(client, &task);
 176
 177     buf = g_try_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 178     if (nb_sectors && buf == NULL) {
 179         return -ENOMEM;
 180     }
 181
 182     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 183
 184     if (nfs_pwrite_async(client->context, client->fh,
 185                          sector_num * BDRV_SECTOR_SIZE,
 186                          nb_sectors * BDRV_SECTOR_SIZE,
 187                          buf, nfs_co_generic_cb, &task) != 0) {
 188         g_free(buf);
 189         return -ENOMEM;
 190     }
 191
 192     while (!task.complete) {
 193         nfs_set_events(client);
 194         qemu_coroutine_yield();
 195     }
 196
 197     g_free(buf);
 198
 199     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 200         return task.ret < 0 ? task.ret : -EIO;
 201     }
 202
 203     return 0;
 204 }
 205
 206 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 207 {
 208     NFSClient *client = bs->opaque;
 209     NFSRPC task;
 210
 211     nfs_co_init_task(client, &task);
 212
 213     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 214                         &task) != 0) {
 215         return -ENOMEM;
 216     }
 217
 218     while (!task.complete) {
 219         nfs_set_events(client);
 220         qemu_coroutine_yield();
 221     }
 222
 223     return task.ret;
 224 }
 225
 226 /* TODO Convert to fine grained options */
 227 static QemuOptsList runtime_opts = {
 228     .name = "nfs",
 229     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 230     .desc = {
 231         {
 232             .name = "filename",
 233             .type = QEMU_OPT_STRING,
 234             .help = "URL to the NFS file",
 235         },
 236         { /* end of list */ }
 237     },
 238 };
 239
 240 static void nfs_detach_aio_context(BlockDriverState *bs)
 241 {
 242     NFSClient *client = bs->opaque;
 243
 244     aio_set_fd_handler(client->aio_context,
 245                        nfs_get_fd(client->context),
 246                        NULL, NULL, NULL);
 247     client->events = 0;
 248 }
 249
 250 static void nfs_attach_aio_context(BlockDriverState *bs,
 251                                    AioContext *new_context)
 252 {
 253     NFSClient *client = bs->opaque;
 254
 255     client->aio_context = new_context;
 256     nfs_set_events(client);
 257 }
 258
 259 static void nfs_client_close(NFSClient *client)
 260 {
 261     if (client->context) {
 262         if (client->fh) {
 263             nfs_close(client->context, client->fh);
 264         }
 265         aio_set_fd_handler(client->aio_context,
 266                            nfs_get_fd(client->context),
 267                            NULL, NULL, NULL);
 268         nfs_destroy_context(client->context);
 269     }
 270     memset(client, 0, sizeof(NFSClient));
 271 }
 272
 273 static void nfs_file_close(BlockDriverState *bs)
 274 {
 275     NFSClient *client = bs->opaque;
 276     nfs_client_close(client);
 277 }
 278
 279 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 280                                int flags, Error **errp)
 281 {
 282     int ret = -EINVAL, i;
 283     struct stat st;
 284     URI *uri;
 285     QueryParams *qp = NULL;
 286     char *file = NULL, *strp = NULL;
 287
 288     uri = uri_parse(filename);
 289     if (!uri) {
 290         error_setg(errp, "Invalid URL specified");
 291         goto fail;
 292     }
 293     if (!uri->server) {
 294         error_setg(errp, "Invalid URL specified");
 295         goto fail;
 296     }
 297     strp = strrchr(uri->path, '/');
 298     if (strp == NULL) {
 299         error_setg(errp, "Invalid URL specified");
 300         goto fail;
 301     }
 302     file = g_strdup(strp);
 303     *strp = 0;
 304
 305     client->context = nfs_init_context();
 306     if (client->context == NULL) {
 307         error_setg(errp, "Failed to init NFS context");
 308         goto fail;
 309     }
 310
 311     qp = query_params_parse(uri->query);
 312     for (i = 0; i < qp->n; i++) {
 313         unsigned long long val;
 314         if (!qp->p[i].value) {
 315             error_setg(errp, "Value for NFS parameter expected: %s",
 316                        qp->p[i].name);
 317             goto fail;
 318         }
 319         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 320             error_setg(errp, "Illegal value for NFS parameter: %s",
 321                        qp->p[i].name);
 322             goto fail;
 323         }
 324         if (!strcmp(qp->p[i].name, "uid")) {
 325             nfs_set_uid(client->context, val);
 326         } else if (!strcmp(qp->p[i].name, "gid")) {
 327             nfs_set_gid(client->context, val);
 328         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 329             nfs_set_tcp_syncnt(client->context, val);
 330 #ifdef LIBNFS_FEATURE_READAHEAD
 331         } else if (!strcmp(qp->p[i].name, "readahead")) {
 332             if (val > QEMU_NFS_MAX_READAHEAD_SIZE) {
 333                 error_report("NFS Warning: Truncating NFS readahead"
 334                              " size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
 335                 val = QEMU_NFS_MAX_READAHEAD_SIZE;
 336             }
 337             nfs_set_readahead(client->context, val);
 338 #endif
 339         } else {
 340             error_setg(errp, "Unknown NFS parameter name: %s",
 341                        qp->p[i].name);
 342             goto fail;
 343         }
 344     }
 345
 346     ret = nfs_mount(client->context, uri->server, uri->path);
 347     if (ret < 0) {
 348         error_setg(errp, "Failed to mount nfs share: %s",
 349                    nfs_get_error(client->context));
 350         goto fail;
 351     }
 352
 353     if (flags & O_CREAT) {
 354         ret = nfs_creat(client->context, file, 0600, &client->fh);
 355         if (ret < 0) {
 356             error_setg(errp, "Failed to create file: %s",
 357                        nfs_get_error(client->context));
 358             goto fail;
 359         }
 360     } else {
 361         ret = nfs_open(client->context, file, flags, &client->fh);
 362         if (ret < 0) {
 363             error_setg(errp, "Failed to open file : %s",
 364                        nfs_get_error(client->context));
 365             goto fail;
 366         }
 367     }
 368
 369     ret = nfs_fstat(client->context, client->fh, &st);
 370     if (ret < 0) {
 371         error_setg(errp, "Failed to fstat file: %s",
 372                    nfs_get_error(client->context));
 373         goto fail;
 374     }
 375
 376     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 377     client->has_zero_init = S_ISREG(st.st_mode);
 378     goto out;
 379 fail:
 380     nfs_client_close(client);
 381 out:
 382     if (qp) {
 383         query_params_free(qp);
 384     }
 385     uri_free(uri);
 386     g_free(file);
 387     return ret;
 388 }
 389
 390 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 391                          Error **errp) {
 392     NFSClient *client = bs->opaque;
 393     int64_t ret;
 394     QemuOpts *opts;
 395     Error *local_err = NULL;
 396
 397     client->aio_context = bdrv_get_aio_context(bs);
 398
 399     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 400     qemu_opts_absorb_qdict(opts, options, &local_err);
 401     if (local_err) {
 402         error_propagate(errp, local_err);
 403         ret = -EINVAL;
 404         goto out;
 405     }
 406     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 407                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 408                           errp);
 409     if (ret < 0) {
 410         goto out;
 411     }
 412     bs->total_sectors = ret;
 413     ret = 0;
 414 out:
 415     qemu_opts_del(opts);
 416     return ret;
 417 }
 418
 419 static QemuOptsList nfs_create_opts = {
 420     .name = "nfs-create-opts",
 421     .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head),
 422     .desc = {
 423         {
 424             .name = BLOCK_OPT_SIZE,
 425             .type = QEMU_OPT_SIZE,
 426             .help = "Virtual disk size"
 427         },
 428         { /* end of list */ }
 429     }
 430 };
 431
 432 static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
 433 {
 434     int ret = 0;
 435     int64_t total_size = 0;
 436     NFSClient *client = g_new0(NFSClient, 1);
 437
 438     client->aio_context = qemu_get_aio_context();
 439
 440     /* Read out options */
 441     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 442                           BDRV_SECTOR_SIZE);
 443
 444     ret = nfs_client_open(client, url, O_CREAT, errp);
 445     if (ret < 0) {
 446         goto out;
 447     }
 448     ret = nfs_ftruncate(client->context, client->fh, total_size);
 449     nfs_client_close(client);
 450 out:
 451     g_free(client);
 452     return ret;
 453 }
 454
 455 static int nfs_has_zero_init(BlockDriverState *bs)
 456 {
 457     NFSClient *client = bs->opaque;
 458     return client->has_zero_init;
 459 }
 460
 461 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 462 {
 463     NFSClient *client = bs->opaque;
 464     NFSRPC task = {0};
 465     struct stat st;
 466
 467     task.st = &st;
 468     if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
 469                         &task) != 0) {
 470         return -ENOMEM;
 471     }
 472
 473     while (!task.complete) {
 474         nfs_set_events(client);
 475         aio_poll(client->aio_context, true);
 476     }
 477
 478     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 479 }
 480
 481 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 482 {
 483     NFSClient *client = bs->opaque;
 484     return nfs_ftruncate(client->context, client->fh, offset);
 485 }
 486
 487 static BlockDriver bdrv_nfs = {
 488     .format_name                    = "nfs",
 489     .protocol_name                  = "nfs",
 490
 491     .instance_size                  = sizeof(NFSClient),
 492     .bdrv_needs_filename            = true,
 493     .create_opts                    = &nfs_create_opts,
 494
 495     .bdrv_has_zero_init             = nfs_has_zero_init,
 496     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 497     .bdrv_truncate                  = nfs_file_truncate,
 498
 499     .bdrv_file_open                 = nfs_file_open,
 500     .bdrv_close                     = nfs_file_close,
 501     .bdrv_create                    = nfs_file_create,
 502
 503     .bdrv_co_readv                  = nfs_co_readv,
 504     .bdrv_co_writev                 = nfs_co_writev,
 505     .bdrv_co_flush_to_disk          = nfs_co_flush,
 506
 507     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 508     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 509 };
 510
 511 static void nfs_block_init(void)
 512 {
 513     bdrv_register(&bdrv_nfs);
 514 }
 515
 516 block_init(nfs_block_init);