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 } NFSClient;
  44
  45 typedef struct NFSRPC {
  46     int ret;
  47     int complete;
  48     QEMUIOVector *iov;
  49     struct stat *st;
  50     Coroutine *co;
  51     QEMUBH *bh;
  52 } NFSRPC;
  53
  54 static void nfs_process_read(void *arg);
  55 static void nfs_process_write(void *arg);
  56
  57 static void nfs_set_events(NFSClient *client)
  58 {
  59     int ev = nfs_which_events(client->context);
  60     if (ev != client->events) {
  61         qemu_aio_set_fd_handler(nfs_get_fd(client->context),
  62                       (ev & POLLIN) ? nfs_process_read : NULL,
  63                       (ev & POLLOUT) ? nfs_process_write : NULL,
  64                       client);
  65
  66     }
  67     client->events = ev;
  68 }
  69
  70 static void nfs_process_read(void *arg)
  71 {
  72     NFSClient *client = arg;
  73     nfs_service(client->context, POLLIN);
  74     nfs_set_events(client);
  75 }
  76
  77 static void nfs_process_write(void *arg)
  78 {
  79     NFSClient *client = arg;
  80     nfs_service(client->context, POLLOUT);
  81     nfs_set_events(client);
  82 }
  83
  84 static void nfs_co_init_task(NFSClient *client, NFSRPC *task)
  85 {
  86     *task = (NFSRPC) {
  87         .co         = qemu_coroutine_self(),
  88     };
  89 }
  90
  91 static void nfs_co_generic_bh_cb(void *opaque)
  92 {
  93     NFSRPC *task = opaque;
  94     qemu_bh_delete(task->bh);
  95     qemu_coroutine_enter(task->co, NULL);
  96 }
  97
  98 static void
  99 nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
 100                   void *private_data)
 101 {
 102     NFSRPC *task = private_data;
 103     task->complete = 1;
 104     task->ret = ret;
 105     if (task->ret > 0 && task->iov) {
 106         if (task->ret <= task->iov->size) {
 107             qemu_iovec_from_buf(task->iov, 0, data, task->ret);
 108         } else {
 109             task->ret = -EIO;
 110         }
 111     }
 112     if (task->ret == 0 && task->st) {
 113         memcpy(task->st, data, sizeof(struct stat));
 114     }
 115     if (task->co) {
 116         task->bh = qemu_bh_new(nfs_co_generic_bh_cb, task);
 117         qemu_bh_schedule(task->bh);
 118     }
 119 }
 120
 121 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 122                                      int64_t sector_num, int nb_sectors,
 123                                      QEMUIOVector *iov)
 124 {
 125     NFSClient *client = bs->opaque;
 126     NFSRPC task;
 127
 128     nfs_co_init_task(client, &task);
 129     task.iov = iov;
 130
 131     if (nfs_pread_async(client->context, client->fh,
 132                         sector_num * BDRV_SECTOR_SIZE,
 133                         nb_sectors * BDRV_SECTOR_SIZE,
 134                         nfs_co_generic_cb, &task) != 0) {
 135         return -ENOMEM;
 136     }
 137
 138     while (!task.complete) {
 139         nfs_set_events(client);
 140         qemu_coroutine_yield();
 141     }
 142
 143     if (task.ret < 0) {
 144         return task.ret;
 145     }
 146
 147     /* zero pad short reads */
 148     if (task.ret < iov->size) {
 149         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 150     }
 151
 152     return 0;
 153 }
 154
 155 static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 156                                         int64_t sector_num, int nb_sectors,
 157                                         QEMUIOVector *iov)
 158 {
 159     NFSClient *client = bs->opaque;
 160     NFSRPC task;
 161     char *buf = NULL;
 162
 163     nfs_co_init_task(client, &task);
 164
 165     buf = g_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 166     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 167
 168     if (nfs_pwrite_async(client->context, client->fh,
 169                          sector_num * BDRV_SECTOR_SIZE,
 170                          nb_sectors * BDRV_SECTOR_SIZE,
 171                          buf, nfs_co_generic_cb, &task) != 0) {
 172         g_free(buf);
 173         return -ENOMEM;
 174     }
 175
 176     while (!task.complete) {
 177         nfs_set_events(client);
 178         qemu_coroutine_yield();
 179     }
 180
 181     g_free(buf);
 182
 183     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 184         return task.ret < 0 ? task.ret : -EIO;
 185     }
 186
 187     return 0;
 188 }
 189
 190 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 191 {
 192     NFSClient *client = bs->opaque;
 193     NFSRPC task;
 194
 195     nfs_co_init_task(client, &task);
 196
 197     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 198                         &task) != 0) {
 199         return -ENOMEM;
 200     }
 201
 202     while (!task.complete) {
 203         nfs_set_events(client);
 204         qemu_coroutine_yield();
 205     }
 206
 207     return task.ret;
 208 }
 209
 210 /* TODO Convert to fine grained options */
 211 static QemuOptsList runtime_opts = {
 212     .name = "nfs",
 213     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 214     .desc = {
 215         {
 216             .name = "filename",
 217             .type = QEMU_OPT_STRING,
 218             .help = "URL to the NFS file",
 219         },
 220         { /* end of list */ }
 221     },
 222 };
 223
 224 static void nfs_client_close(NFSClient *client)
 225 {
 226     if (client->context) {
 227         if (client->fh) {
 228             nfs_close(client->context, client->fh);
 229         }
 230         qemu_aio_set_fd_handler(nfs_get_fd(client->context), NULL, NULL, NULL);
 231         nfs_destroy_context(client->context);
 232     }
 233     memset(client, 0, sizeof(NFSClient));
 234 }
 235
 236 static void nfs_file_close(BlockDriverState *bs)
 237 {
 238     NFSClient *client = bs->opaque;
 239     nfs_client_close(client);
 240 }
 241
 242 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 243                                int flags, Error **errp)
 244 {
 245     int ret = -EINVAL, i;
 246     struct stat st;
 247     URI *uri;
 248     QueryParams *qp = NULL;
 249     char *file = NULL, *strp = NULL;
 250
 251     uri = uri_parse(filename);
 252     if (!uri) {
 253         error_setg(errp, "Invalid URL specified");
 254         goto fail;
 255     }
 256     strp = strrchr(uri->path, '/');
 257     if (strp == NULL) {
 258         error_setg(errp, "Invalid URL specified");
 259         goto fail;
 260     }
 261     file = g_strdup(strp);
 262     *strp = 0;
 263
 264     client->context = nfs_init_context();
 265     if (client->context == NULL) {
 266         error_setg(errp, "Failed to init NFS context");
 267         goto fail;
 268     }
 269
 270     qp = query_params_parse(uri->query);
 271     for (i = 0; i < qp->n; i++) {
 272         if (!qp->p[i].value) {
 273             error_setg(errp, "Value for NFS parameter expected: %s",
 274                        qp->p[i].name);
 275             goto fail;
 276         }
 277         if (!strncmp(qp->p[i].name, "uid", 3)) {
 278             nfs_set_uid(client->context, atoi(qp->p[i].value));
 279         } else if (!strncmp(qp->p[i].name, "gid", 3)) {
 280             nfs_set_gid(client->context, atoi(qp->p[i].value));
 281         } else if (!strncmp(qp->p[i].name, "tcp-syncnt", 10)) {
 282             nfs_set_tcp_syncnt(client->context, atoi(qp->p[i].value));
 283         } else {
 284             error_setg(errp, "Unknown NFS parameter name: %s",
 285                        qp->p[i].name);
 286             goto fail;
 287         }
 288     }
 289
 290     ret = nfs_mount(client->context, uri->server, uri->path);
 291     if (ret < 0) {
 292         error_setg(errp, "Failed to mount nfs share: %s",
 293                    nfs_get_error(client->context));
 294         goto fail;
 295     }
 296
 297     if (flags & O_CREAT) {
 298         ret = nfs_creat(client->context, file, 0600, &client->fh);
 299         if (ret < 0) {
 300             error_setg(errp, "Failed to create file: %s",
 301                        nfs_get_error(client->context));
 302             goto fail;
 303         }
 304     } else {
 305         ret = nfs_open(client->context, file, flags, &client->fh);
 306         if (ret < 0) {
 307             error_setg(errp, "Failed to open file : %s",
 308                        nfs_get_error(client->context));
 309             goto fail;
 310         }
 311     }
 312
 313     ret = nfs_fstat(client->context, client->fh, &st);
 314     if (ret < 0) {
 315         error_setg(errp, "Failed to fstat file: %s",
 316                    nfs_get_error(client->context));
 317         goto fail;
 318     }
 319
 320     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 321     client->has_zero_init = S_ISREG(st.st_mode);
 322     goto out;
 323 fail:
 324     nfs_client_close(client);
 325 out:
 326     if (qp) {
 327         query_params_free(qp);
 328     }
 329     uri_free(uri);
 330     g_free(file);
 331     return ret;
 332 }
 333
 334 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 335                          Error **errp) {
 336     NFSClient *client = bs->opaque;
 337     int64_t ret;
 338     QemuOpts *opts;
 339     Error *local_err = NULL;
 340
 341     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 342     qemu_opts_absorb_qdict(opts, options, &local_err);
 343     if (error_is_set(&local_err)) {
 344         error_propagate(errp, local_err);
 345         return -EINVAL;
 346     }
 347     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 348                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 349                           errp);
 350     if (ret < 0) {
 351         return ret;
 352     }
 353     bs->total_sectors = ret;
 354     return 0;
 355 }
 356
 357 static int nfs_file_create(const char *url, QEMUOptionParameter *options,
 358                            Error **errp)
 359 {
 360     int ret = 0;
 361     int64_t total_size = 0;
 362     NFSClient *client = g_malloc0(sizeof(NFSClient));
 363
 364     /* Read out options */
 365     while (options && options->name) {
 366         if (!strcmp(options->name, "size")) {
 367             total_size = options->value.n;
 368         }
 369         options++;
 370     }
 371
 372     ret = nfs_client_open(client, url, O_CREAT, errp);
 373     if (ret < 0) {
 374         goto out;
 375     }
 376     ret = nfs_ftruncate(client->context, client->fh, total_size);
 377     nfs_client_close(client);
 378 out:
 379     g_free(client);
 380     return ret;
 381 }
 382
 383 static int nfs_has_zero_init(BlockDriverState *bs)
 384 {
 385     NFSClient *client = bs->opaque;
 386     return client->has_zero_init;
 387 }
 388
 389 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 390 {
 391     NFSClient *client = bs->opaque;
 392     NFSRPC task = {0};
 393     struct stat st;
 394
 395     task.st = &st;
 396     if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
 397                         &task) != 0) {
 398         return -ENOMEM;
 399     }
 400
 401     while (!task.complete) {
 402         nfs_set_events(client);
 403         qemu_aio_wait();
 404     }
 405
 406     return (task.ret < 0 ? task.ret : st.st_blocks * st.st_blksize);
 407 }
 408
 409 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 410 {
 411     NFSClient *client = bs->opaque;
 412     return nfs_ftruncate(client->context, client->fh, offset);
 413 }
 414
 415 static BlockDriver bdrv_nfs = {
 416     .format_name     = "nfs",
 417     .protocol_name   = "nfs",
 418
 419     .instance_size   = sizeof(NFSClient),
 420     .bdrv_needs_filename = true,
 421     .bdrv_has_zero_init = nfs_has_zero_init,
 422     .bdrv_get_allocated_file_size = nfs_get_allocated_file_size,
 423     .bdrv_truncate = nfs_file_truncate,
 424
 425     .bdrv_file_open  = nfs_file_open,
 426     .bdrv_close      = nfs_file_close,
 427     .bdrv_create     = nfs_file_create,
 428
 429     .bdrv_co_readv         = nfs_co_readv,
 430     .bdrv_co_writev        = nfs_co_writev,
 431     .bdrv_co_flush_to_disk = nfs_co_flush,
 432 };
 433
 434 static void nfs_block_init(void)
 435 {
 436     bdrv_register(&bdrv_nfs);
 437 }
 438
 439 block_init(nfs_block_init);