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 typedef struct NFSClient {
  39     struct nfs_context *context;
  40     struct nfsfh *fh;
  41     int events;
  42     bool has_zero_init;
  43     AioContext *aio_context;
  44 } NFSClient;
  45
  46 typedef struct NFSRPC {
  47     int ret;
  48     int complete;
  49     QEMUIOVector *iov;
  50     struct stat *st;
  51     Coroutine *co;
  52     QEMUBH *bh;
  53     NFSClient *client;
  54 } NFSRPC;
  55
  56 static void nfs_process_read(void *arg);
  57 static void nfs_process_write(void *arg);
  58
  59 static void nfs_set_events(NFSClient *client)
  60 {
  61     int ev = nfs_which_events(client->context);
  62     if (ev != client->events) {
  63         aio_set_fd_handler(client->aio_context,
  64                            nfs_get_fd(client->context),
  65                            (ev & POLLIN) ? nfs_process_read : NULL,
  66                            (ev & POLLOUT) ? nfs_process_write : NULL,
  67                            client);
  68
  69     }
  70     client->events = ev;
  71 }
  72
  73 static void nfs_process_read(void *arg)
  74 {
  75     NFSClient *client = arg;
  76     nfs_service(client->context, POLLIN);
  77     nfs_set_events(client);
  78 }
  79
  80 static void nfs_process_write(void *arg)
  81 {
  82     NFSClient *client = arg;
  83     nfs_service(client->context, POLLOUT);
  84     nfs_set_events(client);
  85 }
  86
  87 static void nfs_co_init_task(NFSClient *client, NFSRPC *task)
  88 {
  89     *task = (NFSRPC) {
  90         .co             = qemu_coroutine_self(),
  91         .client         = client,
  92     };
  93 }
  94
  95 static void nfs_co_generic_bh_cb(void *opaque)
  96 {
  97     NFSRPC *task = opaque;
  98     task->complete = 1;
  99     qemu_bh_delete(task->bh);
 100     qemu_coroutine_enter(task->co, NULL);
 101 }
 102
 103 static void
 104 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 105                   void *private_data)
 106 {
 107     NFSRPC *task = private_data;
 108     task->ret = ret;
 109     if (task->ret > 0 && task->iov) {
 110         if (task->ret <= task->iov->size) {
 111             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 112         } else {
 113             task->ret = -EIO;
 114         }
 115     }
 116     if (task->ret == 0 && task->st) {
 117         memcpy(task->st, data, sizeof(struct stat));
 118     }
 119     if (task->ret < 0) {
 120         error_report("NFS Error: %s", nfs_get_error(nfs));
 121     }
 122     if (task->co) {
 123         task->bh = aio_bh_new(task->client->aio_context,
 124                               nfs_co_generic_bh_cb, task);
 125         qemu_bh_schedule(task->bh);
 126     } else {
 127         task->complete = 1;
 128     }
 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(client, &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     while (!task.complete) {
 149         nfs_set_events(client);
 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(client, &task);
 174
 175     buf = g_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 176     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 177
 178     if (nfs_pwrite_async(client->context, client->fh,
 179                          sector_num * BDRV_SECTOR_SIZE,
 180                          nb_sectors * BDRV_SECTOR_SIZE,
 181                          buf, nfs_co_generic_cb, &task) != 0) {
 182         g_free(buf);
 183         return -ENOMEM;
 184     }
 185
 186     while (!task.complete) {
 187         nfs_set_events(client);
 188         qemu_coroutine_yield();
 189     }
 190
 191     g_free(buf);
 192
 193     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 194         return task.ret < 0 ? task.ret : -EIO;
 195     }
 196
 197     return 0;
 198 }
 199
 200 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 201 {
 202     NFSClient *client = bs->opaque;
 203     NFSRPC task;
 204
 205     nfs_co_init_task(client, &task);
 206
 207     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 208                         &task) != 0) {
 209         return -ENOMEM;
 210     }
 211
 212     while (!task.complete) {
 213         nfs_set_events(client);
 214         qemu_coroutine_yield();
 215     }
 216
 217     return task.ret;
 218 }
 219
 220 /* TODO Convert to fine grained options */
 221 static QemuOptsList runtime_opts = {
 222     .name = "nfs",
 223     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 224     .desc = {
 225         {
 226             .name = "filename",
 227             .type = QEMU_OPT_STRING,
 228             .help = "URL to the NFS file",
 229         },
 230         { /* end of list */ }
 231     },
 232 };
 233
 234 static void nfs_detach_aio_context(BlockDriverState *bs)
 235 {
 236     NFSClient *client = bs->opaque;
 237
 238     aio_set_fd_handler(client->aio_context,
 239                        nfs_get_fd(client->context),
 240                        NULL, NULL, NULL);
 241     client->events = 0;
 242 }
 243
 244 static void nfs_attach_aio_context(BlockDriverState *bs,
 245                                    AioContext *new_context)
 246 {
 247     NFSClient *client = bs->opaque;
 248
 249     client->aio_context = new_context;
 250     nfs_set_events(client);
 251 }
 252
 253 static void nfs_client_close(NFSClient *client)
 254 {
 255     if (client->context) {
 256         if (client->fh) {
 257             nfs_close(client->context, client->fh);
 258         }
 259         aio_set_fd_handler(client->aio_context,
 260                            nfs_get_fd(client->context),
 261                            NULL, NULL, NULL);
 262         nfs_destroy_context(client->context);
 263     }
 264     memset(client, 0, sizeof(NFSClient));
 265 }
 266
 267 static void nfs_file_close(BlockDriverState *bs)
 268 {
 269     NFSClient *client = bs->opaque;
 270     nfs_client_close(client);
 271 }
 272
 273 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 274                                int flags, Error **errp)
 275 {
 276     int ret = -EINVAL, i;
 277     struct stat st;
 278     URI *uri;
 279     QueryParams *qp = NULL;
 280     char *file = NULL, *strp = NULL;
 281
 282     uri = uri_parse(filename);
 283     if (!uri) {
 284         error_setg(errp, "Invalid URL specified");
 285         goto fail;
 286     }
 287     if (!uri->server) {
 288         error_setg(errp, "Invalid URL specified");
 289         goto fail;
 290     }
 291     strp = strrchr(uri->path, '/');
 292     if (strp == NULL) {
 293         error_setg(errp, "Invalid URL specified");
 294         goto fail;
 295     }
 296     file = g_strdup(strp);
 297     *strp = 0;
 298
 299     client->context = nfs_init_context();
 300     if (client->context == NULL) {
 301         error_setg(errp, "Failed to init NFS context");
 302         goto fail;
 303     }
 304
 305     qp = query_params_parse(uri->query);
 306     for (i = 0; i < qp->n; i++) {
 307         unsigned long long val;
 308         if (!qp->p[i].value) {
 309             error_setg(errp, "Value for NFS parameter expected: %s",
 310                        qp->p[i].name);
 311             goto fail;
 312         }
 313         if (parse_uint_full(qp->p[i].value, &val, 0)) {
 314             error_setg(errp, "Illegal value for NFS parameter: %s",
 315                        qp->p[i].name);
 316             goto fail;
 317         }
 318         if (!strcmp(qp->p[i].name, "uid")) {
 319             nfs_set_uid(client->context, val);
 320         } else if (!strcmp(qp->p[i].name, "gid")) {
 321             nfs_set_gid(client->context, val);
 322         } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) {
 323             nfs_set_tcp_syncnt(client->context, val);
 324 #ifdef LIBNFS_FEATURE_READAHEAD
 325         } else if (!strcmp(qp->p[i].name, "readahead")) {
 326             nfs_set_readahead(client->context, val);
 327 #endif
 328         } else {
 329             error_setg(errp, "Unknown NFS parameter name: %s",
 330                        qp->p[i].name);
 331             goto fail;
 332         }
 333     }
 334
 335     ret = nfs_mount(client->context, uri->server, uri->path);
 336     if (ret < 0) {
 337         error_setg(errp, "Failed to mount nfs share: %s",
 338                    nfs_get_error(client->context));
 339         goto fail;
 340     }
 341
 342     if (flags & O_CREAT) {
 343         ret = nfs_creat(client->context, file, 0600, &client->fh);
 344         if (ret < 0) {
 345             error_setg(errp, "Failed to create file: %s",
 346                        nfs_get_error(client->context));
 347             goto fail;
 348         }
 349     } else {
 350         ret = nfs_open(client->context, file, flags, &client->fh);
 351         if (ret < 0) {
 352             error_setg(errp, "Failed to open file : %s",
 353                        nfs_get_error(client->context));
 354             goto fail;
 355         }
 356     }
 357
 358     ret = nfs_fstat(client->context, client->fh, &st);
 359     if (ret < 0) {
 360         error_setg(errp, "Failed to fstat file: %s",
 361                    nfs_get_error(client->context));
 362         goto fail;
 363     }
 364
 365     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 366     client->has_zero_init = S_ISREG(st.st_mode);
 367     goto out;
 368 fail:
 369     nfs_client_close(client);
 370 out:
 371     if (qp) {
 372         query_params_free(qp);
 373     }
 374     uri_free(uri);
 375     g_free(file);
 376     return ret;
 377 }
 378
 379 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 380                          Error **errp) {
 381     NFSClient *client = bs->opaque;
 382     int64_t ret;
 383     QemuOpts *opts;
 384     Error *local_err = NULL;
 385
 386     client->aio_context = bdrv_get_aio_context(bs);
 387
 388     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 389     qemu_opts_absorb_qdict(opts, options, &local_err);
 390     if (local_err) {
 391         error_propagate(errp, local_err);
 392         return -EINVAL;
 393     }
 394     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 395                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 396                           errp);
 397     if (ret < 0) {
 398         return ret;
 399     }
 400     bs->total_sectors = ret;
 401     return 0;
 402 }
 403
 404 static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
 405 {
 406     int ret = 0;
 407     int64_t total_size = 0;
 408     NFSClient *client = g_malloc0(sizeof(NFSClient));
 409
 410     client->aio_context = qemu_get_aio_context();
 411
 412     /* Read out options */
 413     total_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 414
 415     ret = nfs_client_open(client, url, O_CREAT, errp);
 416     if (ret < 0) {
 417         goto out;
 418     }
 419     ret = nfs_ftruncate(client->context, client->fh, total_size);
 420     nfs_client_close(client);
 421 out:
 422     g_free(client);
 423     return ret;
 424 }
 425
 426 static int nfs_has_zero_init(BlockDriverState *bs)
 427 {
 428     NFSClient *client = bs->opaque;
 429     return client->has_zero_init;
 430 }
 431
 432 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 433 {
 434     NFSClient *client = bs->opaque;
 435     NFSRPC task = {0};
 436     struct stat st;
 437
 438     task.st = &st;
 439     if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
 440                         &task) != 0) {
 441         return -ENOMEM;
 442     }
 443
 444     while (!task.complete) {
 445         nfs_set_events(client);
 446         aio_poll(client->aio_context, true);
 447     }
 448
 449     return (task.ret < 0 ? task.ret : st.st_blocks * st.st_blksize);
 450 }
 451
 452 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 453 {
 454     NFSClient *client = bs->opaque;
 455     return nfs_ftruncate(client->context, client->fh, offset);
 456 }
 457
 458 static BlockDriver bdrv_nfs = {
 459     .format_name                    = "nfs",
 460     .protocol_name                  = "nfs",
 461
 462     .instance_size                  = sizeof(NFSClient),
 463     .bdrv_needs_filename            = true,
 464     .bdrv_has_zero_init             = nfs_has_zero_init,
 465     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 466     .bdrv_truncate                  = nfs_file_truncate,
 467
 468     .bdrv_file_open                 = nfs_file_open,
 469     .bdrv_close                     = nfs_file_close,
 470     .bdrv_create                    = nfs_file_create,
 471
 472     .bdrv_co_readv                  = nfs_co_readv,
 473     .bdrv_co_writev                 = nfs_co_writev,
 474     .bdrv_co_flush_to_disk          = nfs_co_flush,
 475
 476     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 477     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 478 };
 479
 480 static void nfs_block_init(void)
 481 {
 482     bdrv_register(&bdrv_nfs);
 483 }
 484
 485 block_init(nfs_block_init);