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     qemu_bh_delete(task->bh);
  99     qemu_coroutine_enter(task->co, NULL);
 100 }
 101
 102 static void
 103 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 104                   void *private_data)
 105 {
 106     NFSRPC *task = private_data;
 107     task->complete = 1;
 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     }
 127 }
 128
 129 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 130                                      int64_t sector_num, int nb_sectors,
 131                                      QEMUIOVector *iov)
 132 {
 133     NFSClient *client = bs->opaque;
 134     NFSRPC task;
 135
 136     nfs_co_init_task(client, &task);
 137     task.iov = iov;
 138
 139     if (nfs_pread_async(client->context, client->fh,
 140                         sector_num * BDRV_SECTOR_SIZE,
 141                         nb_sectors * BDRV_SECTOR_SIZE,
 142                         nfs_co_generic_cb, &task) != 0) {
 143         return -ENOMEM;
 144     }
 145
 146     while (!task.complete) {
 147         nfs_set_events(client);
 148         qemu_coroutine_yield();
 149     }
 150
 151     if (task.ret < 0) {
 152         return task.ret;
 153     }
 154
 155     /* zero pad short reads */
 156     if (task.ret < iov->size) {
 157         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 158     }
 159
 160     return 0;
 161 }
 162
 163 static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 164                                         int64_t sector_num, int nb_sectors,
 165                                         QEMUIOVector *iov)
 166 {
 167     NFSClient *client = bs->opaque;
 168     NFSRPC task;
 169     char *buf = NULL;
 170
 171     nfs_co_init_task(client, &task);
 172
 173     buf = g_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 174     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 175
 176     if (nfs_pwrite_async(client->context, client->fh,
 177                          sector_num * BDRV_SECTOR_SIZE,
 178                          nb_sectors * BDRV_SECTOR_SIZE,
 179                          buf, nfs_co_generic_cb, &task) != 0) {
 180         g_free(buf);
 181         return -ENOMEM;
 182     }
 183
 184     while (!task.complete) {
 185         nfs_set_events(client);
 186         qemu_coroutine_yield();
 187     }
 188
 189     g_free(buf);
 190
 191     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 192         return task.ret < 0 ? task.ret : -EIO;
 193     }
 194
 195     return 0;
 196 }
 197
 198 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 199 {
 200     NFSClient *client = bs->opaque;
 201     NFSRPC task;
 202
 203     nfs_co_init_task(client, &task);
 204
 205     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 206                         &task) != 0) {
 207         return -ENOMEM;
 208     }
 209
 210     while (!task.complete) {
 211         nfs_set_events(client);
 212         qemu_coroutine_yield();
 213     }
 214
 215     return task.ret;
 216 }
 217
 218 /* TODO Convert to fine grained options */
 219 static QemuOptsList runtime_opts = {
 220     .name = "nfs",
 221     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 222     .desc = {
 223         {
 224             .name = "filename",
 225             .type = QEMU_OPT_STRING,
 226             .help = "URL to the NFS file",
 227         },
 228         { /* end of list */ }
 229     },
 230 };
 231
 232 static void nfs_detach_aio_context(BlockDriverState *bs)
 233 {
 234     NFSClient *client = bs->opaque;
 235
 236     aio_set_fd_handler(client->aio_context,
 237                        nfs_get_fd(client->context),
 238                        NULL, NULL, NULL);
 239     client->events = 0;
 240 }
 241
 242 static void nfs_attach_aio_context(BlockDriverState *bs,
 243                                    AioContext *new_context)
 244 {
 245     NFSClient *client = bs->opaque;
 246
 247     client->aio_context = new_context;
 248     nfs_set_events(client);
 249 }
 250
 251 static void nfs_client_close(NFSClient *client)
 252 {
 253     if (client->context) {
 254         if (client->fh) {
 255             nfs_close(client->context, client->fh);
 256         }
 257         aio_set_fd_handler(client->aio_context,
 258                            nfs_get_fd(client->context),
 259                            NULL, NULL, NULL);
 260         nfs_destroy_context(client->context);
 261     }
 262     memset(client, 0, sizeof(NFSClient));
 263 }
 264
 265 static void nfs_file_close(BlockDriverState *bs)
 266 {
 267     NFSClient *client = bs->opaque;
 268     nfs_client_close(client);
 269 }
 270
 271 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 272                                int flags, Error **errp)
 273 {
 274     int ret = -EINVAL, i;
 275     struct stat st;
 276     URI *uri;
 277     QueryParams *qp = NULL;
 278     char *file = NULL, *strp = NULL;
 279
 280     uri = uri_parse(filename);
 281     if (!uri) {
 282         error_setg(errp, "Invalid URL specified");
 283         goto fail;
 284     }
 285     if (!uri->server) {
 286         error_setg(errp, "Invalid URL specified");
 287         goto fail;
 288     }
 289     strp = strrchr(uri->path, '/');
 290     if (strp == NULL) {
 291         error_setg(errp, "Invalid URL specified");
 292         goto fail;
 293     }
 294     file = g_strdup(strp);
 295     *strp = 0;
 296
 297     client->context = nfs_init_context();
 298     if (client->context == NULL) {
 299         error_setg(errp, "Failed to init NFS context");
 300         goto fail;
 301     }
 302
 303     qp = query_params_parse(uri->query);
 304     for (i = 0; i < qp->n; i++) {
 305         if (!qp->p[i].value) {
 306             error_setg(errp, "Value for NFS parameter expected: %s",
 307                        qp->p[i].name);
 308             goto fail;
 309         }
 310         if (!strncmp(qp->p[i].name, "uid", 3)) {
 311             nfs_set_uid(client->context, atoi(qp->p[i].value));
 312         } else if (!strncmp(qp->p[i].name, "gid", 3)) {
 313             nfs_set_gid(client->context, atoi(qp->p[i].value));
 314         } else if (!strncmp(qp->p[i].name, "tcp-syncnt", 10)) {
 315             nfs_set_tcp_syncnt(client->context, atoi(qp->p[i].value));
 316         } else {
 317             error_setg(errp, "Unknown NFS parameter name: %s",
 318                        qp->p[i].name);
 319             goto fail;
 320         }
 321     }
 322
 323     ret = nfs_mount(client->context, uri->server, uri->path);
 324     if (ret < 0) {
 325         error_setg(errp, "Failed to mount nfs share: %s",
 326                    nfs_get_error(client->context));
 327         goto fail;
 328     }
 329
 330     if (flags & O_CREAT) {
 331         ret = nfs_creat(client->context, file, 0600, &client->fh);
 332         if (ret < 0) {
 333             error_setg(errp, "Failed to create file: %s",
 334                        nfs_get_error(client->context));
 335             goto fail;
 336         }
 337     } else {
 338         ret = nfs_open(client->context, file, flags, &client->fh);
 339         if (ret < 0) {
 340             error_setg(errp, "Failed to open file : %s",
 341                        nfs_get_error(client->context));
 342             goto fail;
 343         }
 344     }
 345
 346     ret = nfs_fstat(client->context, client->fh, &st);
 347     if (ret < 0) {
 348         error_setg(errp, "Failed to fstat file: %s",
 349                    nfs_get_error(client->context));
 350         goto fail;
 351     }
 352
 353     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 354     client->has_zero_init = S_ISREG(st.st_mode);
 355     goto out;
 356 fail:
 357     nfs_client_close(client);
 358 out:
 359     if (qp) {
 360         query_params_free(qp);
 361     }
 362     uri_free(uri);
 363     g_free(file);
 364     return ret;
 365 }
 366
 367 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 368                          Error **errp) {
 369     NFSClient *client = bs->opaque;
 370     int64_t ret;
 371     QemuOpts *opts;
 372     Error *local_err = NULL;
 373
 374     client->aio_context = bdrv_get_aio_context(bs);
 375
 376     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 377     qemu_opts_absorb_qdict(opts, options, &local_err);
 378     if (local_err) {
 379         error_propagate(errp, local_err);
 380         return -EINVAL;
 381     }
 382     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 383                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 384                           errp);
 385     if (ret < 0) {
 386         return ret;
 387     }
 388     bs->total_sectors = ret;
 389     return 0;
 390 }
 391
 392 static int nfs_file_create(const char *url, QEMUOptionParameter *options,
 393                            Error **errp)
 394 {
 395     int ret = 0;
 396     int64_t total_size = 0;
 397     NFSClient *client = g_malloc0(sizeof(NFSClient));
 398
 399     client->aio_context = qemu_get_aio_context();
 400
 401     /* Read out options */
 402     while (options && options->name) {
 403         if (!strcmp(options->name, "size")) {
 404             total_size = options->value.n;
 405         }
 406         options++;
 407     }
 408
 409     ret = nfs_client_open(client, url, O_CREAT, errp);
 410     if (ret < 0) {
 411         goto out;
 412     }
 413     ret = nfs_ftruncate(client->context, client->fh, total_size);
 414     nfs_client_close(client);
 415 out:
 416     g_free(client);
 417     return ret;
 418 }
 419
 420 static int nfs_has_zero_init(BlockDriverState *bs)
 421 {
 422     NFSClient *client = bs->opaque;
 423     return client->has_zero_init;
 424 }
 425
 426 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 427 {
 428     NFSClient *client = bs->opaque;
 429     NFSRPC task = {0};
 430     struct stat st;
 431
 432     task.st = &st;
 433     if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
 434                         &task) != 0) {
 435         return -ENOMEM;
 436     }
 437
 438     while (!task.complete) {
 439         nfs_set_events(client);
 440         aio_poll(client->aio_context, true);
 441     }
 442
 443     return (task.ret < 0 ? task.ret : st.st_blocks * st.st_blksize);
 444 }
 445
 446 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 447 {
 448     NFSClient *client = bs->opaque;
 449     return nfs_ftruncate(client->context, client->fh, offset);
 450 }
 451
 452 static BlockDriver bdrv_nfs = {
 453     .format_name                    = "nfs",
 454     .protocol_name                  = "nfs",
 455
 456     .instance_size                  = sizeof(NFSClient),
 457     .bdrv_needs_filename            = true,
 458     .bdrv_has_zero_init             = nfs_has_zero_init,
 459     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
 460     .bdrv_truncate                  = nfs_file_truncate,
 461
 462     .bdrv_file_open                 = nfs_file_open,
 463     .bdrv_close                     = nfs_file_close,
 464     .bdrv_create                    = nfs_file_create,
 465
 466     .bdrv_co_readv                  = nfs_co_readv,
 467     .bdrv_co_writev                 = nfs_co_writev,
 468     .bdrv_co_flush_to_disk          = nfs_co_flush,
 469
 470     .bdrv_detach_aio_context        = nfs_detach_aio_context,
 471     .bdrv_attach_aio_context        = nfs_attach_aio_context,
 472 };
 473
 474 static void nfs_block_init(void)
 475 {
 476     bdrv_register(&bdrv_nfs);
 477 }
 478
 479 block_init(nfs_block_init);