/* * QEMU Block driver for native access to files on NFS shares * * Copyright (c) 2014-2017 Peter Lieven <pl@kamp.de> * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include <poll.h> #include "qemu/config-file.h" #include "qemu/error-report.h" #include "qapi/error.h" #include "block/block_int.h" #include "block/qdict.h" #include "trace.h" #include "qemu/iov.h" #include "qemu/main-loop.h" #include "qemu/module.h" #include "qemu/option.h" #include "qemu/uri.h" #include "qemu/cutils.h" #include "sysemu/sysemu.h" #include "sysemu/replay.h" #include "qapi/qapi-visit-block-core.h" #include "qapi/qmp/qdict.h" #include "qapi/qmp/qstring.h" #include "qapi/qobject-input-visitor.h" #include "qapi/qobject-output-visitor.h" #include <nfsc/libnfs.h> #define QEMU_NFS_MAX_READAHEAD_SIZE 1048576 #define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE) #define QEMU_NFS_MAX_DEBUG_LEVEL 2 typedef struct NFSClient { struct nfs_context *context; struct nfsfh *fh; int events; bool has_zero_init; AioContext *aio_context; QemuMutex mutex; blkcnt_t st_blocks; bool cache_used; NFSServer *server; char *path; int64_t uid, gid, tcp_syncnt, readahead, pagecache, debug; } NFSClient; typedef struct NFSRPC { BlockDriverState *bs; int ret; int complete; QEMUIOVector *iov; struct stat *st; Coroutine *co; NFSClient *client; } NFSRPC; static int nfs_parse_uri(const char *filename, QDict *options, Error **errp) { URI *uri = NULL; QueryParams *qp = NULL; int ret = -EINVAL, i; uri = uri_parse(filename); if (!uri) { error_setg(errp, "Invalid URI specified"); goto out; } if (g_strcmp0(uri->scheme, "nfs") != 0) { error_setg(errp, "URI scheme must be 'nfs'"); goto out; } if (!uri->server) { error_setg(errp, "missing hostname in URI"); goto out; } if (!uri->path) { error_setg(errp, "missing file path in URI"); goto out; } qp = query_params_parse(uri->query); if (!qp) { error_setg(errp, "could not parse query parameters"); goto out; } qdict_put_str(options, "server.host", uri->server); qdict_put_str(options, "server.type", "inet"); qdict_put_str(options, "path", uri->path); for (i = 0; i < qp->n; i++) { unsigned long long val; if (!qp->p[i].value) { error_setg(errp, "Value for NFS parameter expected: %s", qp->p[i].name); goto out; } if (parse_uint_full(qp->p[i].value, &val, 0)) { error_setg(errp, "Illegal value for NFS parameter: %s", qp->p[i].name); goto out; } if (!strcmp(qp->p[i].name, "uid")) { qdict_put_str(options, "user", qp->p[i].value); } else if (!strcmp(qp->p[i].name, "gid")) { qdict_put_str(options, "group", qp->p[i].value); } else if (!strcmp(qp->p[i].name, "tcp-syncnt")) { qdict_put_str(options, "tcp-syn-count", qp->p[i].value); } else if (!strcmp(qp->p[i].name, "readahead")) { qdict_put_str(options, "readahead-size", qp->p[i].value); } else if (!strcmp(qp->p[i].name, "pagecache")) { qdict_put_str(options, "page-cache-size", qp->p[i].value); } else if (!strcmp(qp->p[i].name, "debug")) { qdict_put_str(options, "debug", qp->p[i].value); } else { error_setg(errp, "Unknown NFS parameter name: %s", qp->p[i].name); goto out; } } ret = 0; out: if (qp) { query_params_free(qp); } if (uri) { uri_free(uri); } return ret; } static bool nfs_has_filename_options_conflict(QDict *options, Error **errp) { const QDictEntry *qe; for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) { if (!strcmp(qe->key, "host") || !strcmp(qe->key, "path") || !strcmp(qe->key, "user") || !strcmp(qe->key, "group") || !strcmp(qe->key, "tcp-syn-count") || !strcmp(qe->key, "readahead-size") || !strcmp(qe->key, "page-cache-size") || !strcmp(qe->key, "debug") || strstart(qe->key, "server.", NULL)) { error_setg(errp, "Option %s cannot be used with a filename", qe->key); return true; } } return false; } static void nfs_parse_filename(const char *filename, QDict *options, Error **errp) { if (nfs_has_filename_options_conflict(options, errp)) { return; } nfs_parse_uri(filename, options, errp); } static void nfs_process_read(void *arg); static void nfs_process_write(void *arg); /* Called with QemuMutex held. */ static void nfs_set_events(NFSClient *client) { int ev = nfs_which_events(client->context); if (ev != client->events) { aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context), false, (ev & POLLIN) ? nfs_process_read : NULL, (ev & POLLOUT) ? nfs_process_write : NULL, NULL, client); } client->events = ev; } static void nfs_process_read(void *arg) { NFSClient *client = arg; qemu_mutex_lock(&client->mutex); nfs_service(client->context, POLLIN); nfs_set_events(client); qemu_mutex_unlock(&client->mutex); } static void nfs_process_write(void *arg) { NFSClient *client = arg; qemu_mutex_lock(&client->mutex); nfs_service(client->context, POLLOUT); nfs_set_events(client); qemu_mutex_unlock(&client->mutex); } static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task) { *task = (NFSRPC) { .co = qemu_coroutine_self(), .bs = bs, .client = bs->opaque, }; } static void nfs_co_generic_bh_cb(void *opaque) { NFSRPC *task = opaque; task->complete = 1; aio_co_wake(task->co); } /* Called (via nfs_service) with QemuMutex held. */ static void nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data, void *private_data) { NFSRPC *task = private_data; task->ret = ret; assert(!task->st); if (task->ret > 0 && task->iov) { if (task->ret <= task->iov->size) { qemu_iovec_from_buf(task->iov, 0, data, task->ret); } else { task->ret = -EIO; } } if (task->ret < 0) { error_report("NFS Error: %s", nfs_get_error(nfs)); } replay_bh_schedule_oneshot_event(task->client->aio_context, nfs_co_generic_bh_cb, task); } static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *iov, int flags) { NFSClient *client = bs->opaque; NFSRPC task; nfs_co_init_task(bs, &task); task.iov = iov; WITH_QEMU_LOCK_GUARD(&client->mutex) { if (nfs_pread_async(client->context, client->fh, offset, bytes, nfs_co_generic_cb, &task) != 0) { return -ENOMEM; } nfs_set_events(client); } while (!task.complete) { qemu_coroutine_yield(); } if (task.ret < 0) { return task.ret; } /* zero pad short reads */ if (task.ret < iov->size) { qemu_iovec_memset(iov, task.ret, 0, iov->size - task.ret); } return 0; } static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *iov, int flags) { NFSClient *client = bs->opaque; NFSRPC task; char *buf = NULL; bool my_buffer = false; nfs_co_init_task(bs, &task); if (iov->niov != 1) { buf = g_try_malloc(bytes); if (bytes && buf == NULL) { return -ENOMEM; } qemu_iovec_to_buf(iov, 0, buf, bytes); my_buffer = true; } else { buf = iov->iov[0].iov_base; } WITH_QEMU_LOCK_GUARD(&client->mutex) { if (nfs_pwrite_async(client->context, client->fh, offset, bytes, buf, nfs_co_generic_cb, &task) != 0) { if (my_buffer) { g_free(buf); } return -ENOMEM; } nfs_set_events(client); } while (!task.complete) { qemu_coroutine_yield(); } if (my_buffer) { g_free(buf); } if (task.ret != bytes) { return task.ret < 0 ? task.ret : -EIO; } return 0; } static int coroutine_fn nfs_co_flush(BlockDriverState *bs) { NFSClient *client = bs->opaque; NFSRPC task; nfs_co_init_task(bs, &task); WITH_QEMU_LOCK_GUARD(&client->mutex) { if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb, &task) != 0) { return -ENOMEM; } nfs_set_events(client); } while (!task.complete) { qemu_coroutine_yield(); } return task.ret; } static void nfs_detach_aio_context(BlockDriverState *bs) { NFSClient *client = bs->opaque; aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context), false, NULL, NULL, NULL, NULL); client->events = 0; } static void nfs_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { NFSClient *client = bs->opaque; client->aio_context = new_context; nfs_set_events(client); } static void nfs_client_close(NFSClient *client) { if (client->context) { qemu_mutex_lock(&client->mutex); aio_set_fd_handler(client->aio_context, nfs_get_fd(client->context), false, NULL, NULL, NULL, NULL); qemu_mutex_unlock(&client->mutex); if (client->fh) { nfs_close(client->context, client->fh); client->fh = NULL; } #ifdef LIBNFS_FEATURE_UMOUNT nfs_umount(client->context); #endif nfs_destroy_context(client->context); client->context = NULL; } g_free(client->path); qemu_mutex_destroy(&client->mutex); qapi_free_NFSServer(client->server); client->server = NULL; } static void nfs_file_close(BlockDriverState *bs) { NFSClient *client = bs->opaque; nfs_client_close(client); } static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts, int flags, int open_flags, Error **errp) { int64_t ret = -EINVAL; struct stat st; char *file = NULL, *strp = NULL; qemu_mutex_init(&client->mutex); client->path = g_strdup(opts->path); strp = strrchr(client->path, '/'); if (strp == NULL) { error_setg(errp, "Invalid URL specified"); goto fail; } file = g_strdup(strp); *strp = 0; /* Steal the NFSServer object from opts; set the original pointer to NULL * to avoid use after free and double free. */ client->server = opts->server; opts->server = NULL; client->context = nfs_init_context(); if (client->context == NULL) { error_setg(errp, "Failed to init NFS context"); goto fail; } if (opts->has_user) { client->uid = opts->user; nfs_set_uid(client->context, client->uid); } if (opts->has_group) { client->gid = opts->group; nfs_set_gid(client->context, client->gid); } if (opts->has_tcp_syn_count) { client->tcp_syncnt = opts->tcp_syn_count; nfs_set_tcp_syncnt(client->context, client->tcp_syncnt); } #ifdef LIBNFS_FEATURE_READAHEAD if (opts->has_readahead_size) { if (open_flags & BDRV_O_NOCACHE) { error_setg(errp, "Cannot enable NFS readahead " "if cache.direct = on"); goto fail; } client->readahead = opts->readahead_size; if (client->readahead > QEMU_NFS_MAX_READAHEAD_SIZE) { warn_report("Truncating NFS readahead size to %d", QEMU_NFS_MAX_READAHEAD_SIZE); client->readahead = QEMU_NFS_MAX_READAHEAD_SIZE; } nfs_set_readahead(client->context, client->readahead); #ifdef LIBNFS_FEATURE_PAGECACHE nfs_set_pagecache_ttl(client->context, 0); #endif client->cache_used = true; } #endif #ifdef LIBNFS_FEATURE_PAGECACHE if (opts->has_page_cache_size) { if (open_flags & BDRV_O_NOCACHE) { error_setg(errp, "Cannot enable NFS pagecache " "if cache.direct = on"); goto fail; } client->pagecache = opts->page_cache_size; if (client->pagecache > QEMU_NFS_MAX_PAGECACHE_SIZE) { warn_report("Truncating NFS pagecache size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE); client->pagecache = QEMU_NFS_MAX_PAGECACHE_SIZE; } nfs_set_pagecache(client->context, client->pagecache); nfs_set_pagecache_ttl(client->context, 0); client->cache_used = true; } #endif #ifdef LIBNFS_FEATURE_DEBUG if (opts->has_debug) { client->debug = opts->debug; /* limit the maximum debug level to avoid potential flooding * of our log files. */ if (client->debug > QEMU_NFS_MAX_DEBUG_LEVEL) { warn_report("Limiting NFS debug level to %d", QEMU_NFS_MAX_DEBUG_LEVEL); client->debug = QEMU_NFS_MAX_DEBUG_LEVEL; } nfs_set_debug(client->context, client->debug); } #endif ret = nfs_mount(client->context, client->server->host, client->path); if (ret < 0) { error_setg(errp, "Failed to mount nfs share: %s", nfs_get_error(client->context)); goto fail; } if (flags & O_CREAT) { ret = nfs_creat(client->context, file, 0600, &client->fh); if (ret < 0) { error_setg(errp, "Failed to create file: %s", nfs_get_error(client->context)); goto fail; } } else { ret = nfs_open(client->context, file, flags, &client->fh); if (ret < 0) { error_setg(errp, "Failed to open file : %s", nfs_get_error(client->context)); goto fail; } } ret = nfs_fstat(client->context, client->fh, &st); if (ret < 0) { error_setg(errp, "Failed to fstat file: %s", nfs_get_error(client->context)); goto fail; } ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE); client->st_blocks = st.st_blocks; client->has_zero_init = S_ISREG(st.st_mode); *strp = '/'; goto out; fail: nfs_client_close(client); out: g_free(file); return ret; } static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options, Error **errp) { BlockdevOptionsNfs *opts = NULL; Visitor *v; const QDictEntry *e; v = qobject_input_visitor_new_flat_confused(options, errp); if (!v) { return NULL; } visit_type_BlockdevOptionsNfs(v, NULL, &opts, errp); visit_free(v); if (!opts) { return NULL; } /* Remove the processed options from the QDict (the visitor processes * _all_ options in the QDict) */ while ((e = qdict_first(options))) { qdict_del(options, e->key); } return opts; } static int64_t nfs_client_open_qdict(NFSClient *client, QDict *options, int flags, int open_flags, Error **errp) { BlockdevOptionsNfs *opts; int ret; opts = nfs_options_qdict_to_qapi(options, errp); if (opts == NULL) { ret = -EINVAL; goto fail; } ret = nfs_client_open(client, opts, flags, open_flags, errp); fail: qapi_free_BlockdevOptionsNfs(opts); return ret; } static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { NFSClient *client = bs->opaque; int64_t ret; client->aio_context = bdrv_get_aio_context(bs); ret = nfs_client_open_qdict(client, options, (flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY, bs->open_flags, errp); if (ret < 0) { return ret; } bs->total_sectors = ret; if (client->has_zero_init) { bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; } return 0; } static QemuOptsList nfs_create_opts = { .name = "nfs-create-opts", .head = QTAILQ_HEAD_INITIALIZER(nfs_create_opts.head), .desc = { { .name = BLOCK_OPT_SIZE, .type = QEMU_OPT_SIZE, .help = "Virtual disk size" }, { /* end of list */ } } }; static int nfs_file_co_create(BlockdevCreateOptions *options, Error **errp) { BlockdevCreateOptionsNfs *opts = &options->u.nfs; NFSClient *client = g_new0(NFSClient, 1); int ret; assert(options->driver == BLOCKDEV_DRIVER_NFS); client->aio_context = qemu_get_aio_context(); ret = nfs_client_open(client, opts->location, O_CREAT, 0, errp); if (ret < 0) { goto out; } ret = nfs_ftruncate(client->context, client->fh, opts->size); nfs_client_close(client); out: g_free(client); return ret; } static int coroutine_fn nfs_file_co_create_opts(BlockDriver *drv, const char *url, QemuOpts *opts, Error **errp) { BlockdevCreateOptions *create_options; BlockdevCreateOptionsNfs *nfs_opts; QDict *options; int ret; create_options = g_new0(BlockdevCreateOptions, 1); create_options->driver = BLOCKDEV_DRIVER_NFS; nfs_opts = &create_options->u.nfs; /* Read out options */ nfs_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), BDRV_SECTOR_SIZE); options = qdict_new(); ret = nfs_parse_uri(url, options, errp); if (ret < 0) { goto out; } nfs_opts->location = nfs_options_qdict_to_qapi(options, errp); if (nfs_opts->location == NULL) { ret = -EINVAL; goto out; } ret = nfs_file_co_create(create_options, errp); if (ret < 0) { goto out; } ret = 0; out: qobject_unref(options); qapi_free_BlockdevCreateOptions(create_options); return ret; } static int nfs_has_zero_init(BlockDriverState *bs) { NFSClient *client = bs->opaque; return client->has_zero_init; } /* Called (via nfs_service) with QemuMutex held. */ static void nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data, void *private_data) { NFSRPC *task = private_data; task->ret = ret; if (task->ret == 0) { memcpy(task->st, data, sizeof(struct stat)); } if (task->ret < 0) { error_report("NFS Error: %s", nfs_get_error(nfs)); } /* Set task->complete before reading bs->wakeup. */ atomic_mb_set(&task->complete, 1); bdrv_wakeup(task->bs); } static int64_t nfs_get_allocated_file_size(BlockDriverState *bs) { NFSClient *client = bs->opaque; NFSRPC task = {0}; struct stat st; if (bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_NOCACHE)) { return client->st_blocks * 512; } task.bs = bs; task.st = &st; if (nfs_fstat_async(client->context, client->fh, nfs_get_allocated_file_size_cb, &task) != 0) { return -ENOMEM; } nfs_set_events(client); BDRV_POLL_WHILE(bs, !task.complete); return (task.ret < 0 ? task.ret : st.st_blocks * 512); } static int coroutine_fn nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact, PreallocMode prealloc, BdrvRequestFlags flags, Error **errp) { NFSClient *client = bs->opaque; int ret; if (prealloc != PREALLOC_MODE_OFF) { error_setg(errp, "Unsupported preallocation mode '%s'", PreallocMode_str(prealloc)); return -ENOTSUP; } ret = nfs_ftruncate(client->context, client->fh, offset); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to truncate file"); return ret; } return 0; } /* Note that this will not re-establish a connection with the NFS server * - it is effectively a NOP. */ static int nfs_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue, Error **errp) { NFSClient *client = state->bs->opaque; struct stat st; int ret = 0; if (state->flags & BDRV_O_RDWR && bdrv_is_read_only(state->bs)) { error_setg(errp, "Cannot open a read-only mount as read-write"); return -EACCES; } if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) { error_setg(errp, "Cannot disable cache if libnfs readahead or" " pagecache is enabled"); return -EINVAL; } /* Update cache for read-only reopens */ if (!(state->flags & BDRV_O_RDWR)) { ret = nfs_fstat(client->context, client->fh, &st); if (ret < 0) { error_setg(errp, "Failed to fstat file: %s", nfs_get_error(client->context)); return ret; } client->st_blocks = st.st_blocks; } return 0; } static void nfs_refresh_filename(BlockDriverState *bs) { NFSClient *client = bs->opaque; if (client->uid && !client->gid) { snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nfs://%s%s?uid=%" PRId64, client->server->host, client->path, client->uid); } else if (!client->uid && client->gid) { snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nfs://%s%s?gid=%" PRId64, client->server->host, client->path, client->gid); } else if (client->uid && client->gid) { snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nfs://%s%s?uid=%" PRId64 "&gid=%" PRId64, client->server->host, client->path, client->uid, client->gid); } else { snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nfs://%s%s", client->server->host, client->path); } } static char *nfs_dirname(BlockDriverState *bs, Error **errp) { NFSClient *client = bs->opaque; if (client->uid || client->gid) { bdrv_refresh_filename(bs); error_setg(errp, "Cannot generate a base directory for NFS node '%s'", bs->filename); return NULL; } return g_strdup_printf("nfs://%s%s/", client->server->host, client->path); } #ifdef LIBNFS_FEATURE_PAGECACHE static void coroutine_fn nfs_co_invalidate_cache(BlockDriverState *bs, Error **errp) { NFSClient *client = bs->opaque; nfs_pagecache_invalidate(client->context, client->fh); } #endif static const char *nfs_strong_runtime_opts[] = { "path", "user", "group", "server.", NULL }; static BlockDriver bdrv_nfs = { .format_name = "nfs", .protocol_name = "nfs", .instance_size = sizeof(NFSClient), .bdrv_parse_filename = nfs_parse_filename, .create_opts = &nfs_create_opts, .bdrv_has_zero_init = nfs_has_zero_init, .bdrv_get_allocated_file_size = nfs_get_allocated_file_size, .bdrv_co_truncate = nfs_file_co_truncate, .bdrv_file_open = nfs_file_open, .bdrv_close = nfs_file_close, .bdrv_co_create = nfs_file_co_create, .bdrv_co_create_opts = nfs_file_co_create_opts, .bdrv_reopen_prepare = nfs_reopen_prepare, .bdrv_co_preadv = nfs_co_preadv, .bdrv_co_pwritev = nfs_co_pwritev, .bdrv_co_flush_to_disk = nfs_co_flush, .bdrv_detach_aio_context = nfs_detach_aio_context, .bdrv_attach_aio_context = nfs_attach_aio_context, .bdrv_refresh_filename = nfs_refresh_filename, .bdrv_dirname = nfs_dirname, .strong_runtime_opts = nfs_strong_runtime_opts, #ifdef LIBNFS_FEATURE_PAGECACHE .bdrv_co_invalidate_cache = nfs_co_invalidate_cache, #endif }; static void nfs_block_init(void) { bdrv_register(&bdrv_nfs); } block_init(nfs_block_init);