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->ret < 0) {
 116         error_report("NFS Error: %s", nfs_get_error(nfs));
 117     }
 118     if (task->co) {
 119         task->bh = qemu_bh_new(nfs_co_generic_bh_cb, task);
 120         qemu_bh_schedule(task->bh);
 121     }
 122 }
 123
 124 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 125                                      int64_t sector_num, int nb_sectors,
 126                                      QEMUIOVector *iov)
 127 {
 128     NFSClient *client = bs->opaque;
 129     NFSRPC task;
 130
 131     nfs_co_init_task(client, &task);
 132     task.iov = iov;
 133
 134     if (nfs_pread_async(client->context, client->fh,
 135                         sector_num * BDRV_SECTOR_SIZE,
 136                         nb_sectors * BDRV_SECTOR_SIZE,
 137                         nfs_co_generic_cb, &task) != 0) {
 138         return -ENOMEM;
 139     }
 140
 141     while (!task.complete) {
 142         nfs_set_events(client);
 143         qemu_coroutine_yield();
 144     }
 145
 146     if (task.ret < 0) {
 147         return task.ret;
 148     }
 149
 150     /* zero pad short reads */
 151     if (task.ret < iov->size) {
 152         qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret);
 153     }
 154
 155     return 0;
 156 }
 157
 158 static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 159                                         int64_t sector_num, int nb_sectors,
 160                                         QEMUIOVector *iov)
 161 {
 162     NFSClient *client = bs->opaque;
 163     NFSRPC task;
 164     char *buf = NULL;
 165
 166     nfs_co_init_task(client, &task);
 167
 168     buf = g_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 169     qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
 170
 171     if (nfs_pwrite_async(client->context, client->fh,
 172                          sector_num * BDRV_SECTOR_SIZE,
 173                          nb_sectors * BDRV_SECTOR_SIZE,
 174                          buf, nfs_co_generic_cb, &task) != 0) {
 175         g_free(buf);
 176         return -ENOMEM;
 177     }
 178
 179     while (!task.complete) {
 180         nfs_set_events(client);
 181         qemu_coroutine_yield();
 182     }
 183
 184     g_free(buf);
 185
 186     if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
 187         return task.ret < 0 ? task.ret : -EIO;
 188     }
 189
 190     return 0;
 191 }
 192
 193 static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 194 {
 195     NFSClient *client = bs->opaque;
 196     NFSRPC task;
 197
 198     nfs_co_init_task(client, &task);
 199
 200     if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 201                         &task) != 0) {
 202         return -ENOMEM;
 203     }
 204
 205     while (!task.complete) {
 206         nfs_set_events(client);
 207         qemu_coroutine_yield();
 208     }
 209
 210     return task.ret;
 211 }
 212
 213 /* TODO Convert to fine grained options */
 214 static QemuOptsList runtime_opts = {
 215     .name = "nfs",
 216     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 217     .desc = {
 218         {
 219             .name = "filename",
 220             .type = QEMU_OPT_STRING,
 221             .help = "URL to the NFS file",
 222         },
 223         { /* end of list */ }
 224     },
 225 };
 226
 227 static void nfs_client_close(NFSClient *client)
 228 {
 229     if (client->context) {
 230         if (client->fh) {
 231             nfs_close(client->context, client->fh);
 232         }
 233         qemu_aio_set_fd_handler(nfs_get_fd(client->context), NULL, NULL, NULL);
 234         nfs_destroy_context(client->context);
 235     }
 236     memset(client, 0, sizeof(NFSClient));
 237 }
 238
 239 static void nfs_file_close(BlockDriverState *bs)
 240 {
 241     NFSClient *client = bs->opaque;
 242     nfs_client_close(client);
 243 }
 244
 245 static int64_t nfs_client_open(NFSClient *client, const char *filename,
 246                                int flags, Error **errp)
 247 {
 248     int ret = -EINVAL, i;
 249     struct stat st;
 250     URI *uri;
 251     QueryParams *qp = NULL;
 252     char *file = NULL, *strp = NULL;
 253
 254     uri = uri_parse(filename);
 255     if (!uri) {
 256         error_setg(errp, "Invalid URL specified");
 257         goto fail;
 258     }
 259     strp = strrchr(uri->path, '/');
 260     if (strp == NULL) {
 261         error_setg(errp, "Invalid URL specified");
 262         goto fail;
 263     }
 264     file = g_strdup(strp);
 265     *strp = 0;
 266
 267     client->context = nfs_init_context();
 268     if (client->context == NULL) {
 269         error_setg(errp, "Failed to init NFS context");
 270         goto fail;
 271     }
 272
 273     qp = query_params_parse(uri->query);
 274     for (i = 0; i < qp->n; i++) {
 275         if (!qp->p[i].value) {
 276             error_setg(errp, "Value for NFS parameter expected: %s",
 277                        qp->p[i].name);
 278             goto fail;
 279         }
 280         if (!strncmp(qp->p[i].name, "uid", 3)) {
 281             nfs_set_uid(client->context, atoi(qp->p[i].value));
 282         } else if (!strncmp(qp->p[i].name, "gid", 3)) {
 283             nfs_set_gid(client->context, atoi(qp->p[i].value));
 284         } else if (!strncmp(qp->p[i].name, "tcp-syncnt", 10)) {
 285             nfs_set_tcp_syncnt(client->context, atoi(qp->p[i].value));
 286         } else {
 287             error_setg(errp, "Unknown NFS parameter name: %s",
 288                        qp->p[i].name);
 289             goto fail;
 290         }
 291     }
 292
 293     ret = nfs_mount(client->context, uri->server, uri->path);
 294     if (ret < 0) {
 295         error_setg(errp, "Failed to mount nfs share: %s",
 296                    nfs_get_error(client->context));
 297         goto fail;
 298     }
 299
 300     if (flags & O_CREAT) {
 301         ret = nfs_creat(client->context, file, 0600, &client->fh);
 302         if (ret < 0) {
 303             error_setg(errp, "Failed to create file: %s",
 304                        nfs_get_error(client->context));
 305             goto fail;
 306         }
 307     } else {
 308         ret = nfs_open(client->context, file, flags, &client->fh);
 309         if (ret < 0) {
 310             error_setg(errp, "Failed to open file : %s",
 311                        nfs_get_error(client->context));
 312             goto fail;
 313         }
 314     }
 315
 316     ret = nfs_fstat(client->context, client->fh, &st);
 317     if (ret < 0) {
 318         error_setg(errp, "Failed to fstat file: %s",
 319                    nfs_get_error(client->context));
 320         goto fail;
 321     }
 322
 323     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
 324     client->has_zero_init = S_ISREG(st.st_mode);
 325     goto out;
 326 fail:
 327     nfs_client_close(client);
 328 out:
 329     if (qp) {
 330         query_params_free(qp);
 331     }
 332     uri_free(uri);
 333     g_free(file);
 334     return ret;
 335 }
 336
 337 static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
 338                          Error **errp) {
 339     NFSClient *client = bs->opaque;
 340     int64_t ret;
 341     QemuOpts *opts;
 342     Error *local_err = NULL;
 343
 344     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 345     qemu_opts_absorb_qdict(opts, options, &local_err);
 346     if (local_err) {
 347         error_propagate(errp, local_err);
 348         return -EINVAL;
 349     }
 350     ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
 351                           (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
 352                           errp);
 353     if (ret < 0) {
 354         return ret;
 355     }
 356     bs->total_sectors = ret;
 357     return 0;
 358 }
 359
 360 static int nfs_file_create(const char *url, QEMUOptionParameter *options,
 361                            Error **errp)
 362 {
 363     int ret = 0;
 364     int64_t total_size = 0;
 365     NFSClient *client = g_malloc0(sizeof(NFSClient));
 366
 367     /* Read out options */
 368     while (options && options->name) {
 369         if (!strcmp(options->name, "size")) {
 370             total_size = options->value.n;
 371         }
 372         options++;
 373     }
 374
 375     ret = nfs_client_open(client, url, O_CREAT, errp);
 376     if (ret < 0) {
 377         goto out;
 378     }
 379     ret = nfs_ftruncate(client->context, client->fh, total_size);
 380     nfs_client_close(client);
 381 out:
 382     g_free(client);
 383     return ret;
 384 }
 385
 386 static int nfs_has_zero_init(BlockDriverState *bs)
 387 {
 388     NFSClient *client = bs->opaque;
 389     return client->has_zero_init;
 390 }
 391
 392 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 393 {
 394     NFSClient *client = bs->opaque;
 395     NFSRPC task = {0};
 396     struct stat st;
 397
 398     task.st = &st;
 399     if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
 400                         &task) != 0) {
 401         return -ENOMEM;
 402     }
 403
 404     while (!task.complete) {
 405         nfs_set_events(client);
 406         qemu_aio_wait();
 407     }
 408
 409     return (task.ret < 0 ? task.ret : st.st_blocks * st.st_blksize);
 410 }
 411
 412 static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
 413 {
 414     NFSClient *client = bs->opaque;
 415     return nfs_ftruncate(client->context, client->fh, offset);
 416 }
 417
 418 static BlockDriver bdrv_nfs = {
 419     .format_name     = "nfs",
 420     .protocol_name   = "nfs",
 421
 422     .instance_size   = sizeof(NFSClient),
 423     .bdrv_needs_filename = true,
 424     .bdrv_has_zero_init = nfs_has_zero_init,
 425     .bdrv_get_allocated_file_size = nfs_get_allocated_file_size,
 426     .bdrv_truncate = nfs_file_truncate,
 427
 428     .bdrv_file_open  = nfs_file_open,
 429     .bdrv_close      = nfs_file_close,
 430     .bdrv_create     = nfs_file_create,
 431
 432     .bdrv_co_readv         = nfs_co_readv,
 433     .bdrv_co_writev        = nfs_co_writev,
 434     .bdrv_co_flush_to_disk = nfs_co_flush,
 435 };
 436
 437 static void nfs_block_init(void)
 438 {
 439     bdrv_register(&bdrv_nfs);
 440 }
 441
 442 block_init(nfs_block_init);