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qemu/block/nfs.c

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/*
* QEMU Block driver for native access to files on NFS shares
*
* Copyright (c) 2014 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 "config-host.h"
#include <poll.h>
#include "qemu-common.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"
#include "block/block_int.h"
#include "trace.h"
#include "qemu/iov.h"
#include "qemu/uri.h"
#include "sysemu/sysemu.h"
#include <nfsc/libnfs.h>
typedef struct NFSClient {
struct nfs_context *context;
struct nfsfh *fh;
int events;
bool has_zero_init;
} NFSClient;
typedef struct NFSRPC {
int ret;
int complete;
QEMUIOVector *iov;
struct stat *st;
Coroutine *co;
QEMUBH *bh;
} NFSRPC;
static void nfs_process_read(void *arg);
static void nfs_process_write(void *arg);
static void nfs_set_events(NFSClient *client)
{
int ev = nfs_which_events(client->context);
if (ev != client->events) {
qemu_aio_set_fd_handler(nfs_get_fd(client->context),
(ev & POLLIN) ? nfs_process_read : NULL,
(ev & POLLOUT) ? nfs_process_write : NULL,
client);
}
client->events = ev;
}
static void nfs_process_read(void *arg)
{
NFSClient *client = arg;
nfs_service(client->context, POLLIN);
nfs_set_events(client);
}
static void nfs_process_write(void *arg)
{
NFSClient *client = arg;
nfs_service(client->context, POLLOUT);
nfs_set_events(client);
}
static void nfs_co_init_task(NFSClient *client, NFSRPC *task)
{
*task = (NFSRPC) {
.co = qemu_coroutine_self(),
};
}
static void nfs_co_generic_bh_cb(void *opaque)
{
NFSRPC *task = opaque;
qemu_bh_delete(task->bh);
qemu_coroutine_enter(task->co, NULL);
}
static void
nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
void *private_data)
{
NFSRPC *task = private_data;
task->complete = 1;
task->ret = ret;
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 && task->st) {
memcpy(task->st, data, sizeof(struct stat));
}
if (task->ret < 0) {
error_report("NFS Error: %s", nfs_get_error(nfs));
}
if (task->co) {
task->bh = qemu_bh_new(nfs_co_generic_bh_cb, task);
qemu_bh_schedule(task->bh);
}
}
static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *iov)
{
NFSClient *client = bs->opaque;
NFSRPC task;
nfs_co_init_task(client, &task);
task.iov = iov;
if (nfs_pread_async(client->context, client->fh,
sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
nfs_co_generic_cb, &task) != 0) {
return -ENOMEM;
}
while (!task.complete) {
nfs_set_events(client);
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_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *iov)
{
NFSClient *client = bs->opaque;
NFSRPC task;
char *buf = NULL;
nfs_co_init_task(client, &task);
buf = g_malloc(nb_sectors * BDRV_SECTOR_SIZE);
qemu_iovec_to_buf(iov, 0, buf, nb_sectors * BDRV_SECTOR_SIZE);
if (nfs_pwrite_async(client->context, client->fh,
sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE,
buf, nfs_co_generic_cb, &task) != 0) {
g_free(buf);
return -ENOMEM;
}
while (!task.complete) {
nfs_set_events(client);
qemu_coroutine_yield();
}
g_free(buf);
if (task.ret != nb_sectors * BDRV_SECTOR_SIZE) {
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(client, &task);
if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
&task) != 0) {
return -ENOMEM;
}
while (!task.complete) {
nfs_set_events(client);
qemu_coroutine_yield();
}
return task.ret;
}
/* TODO Convert to fine grained options */
static QemuOptsList runtime_opts = {
.name = "nfs",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = "filename",
.type = QEMU_OPT_STRING,
.help = "URL to the NFS file",
},
{ /* end of list */ }
},
};
static void nfs_client_close(NFSClient *client)
{
if (client->context) {
if (client->fh) {
nfs_close(client->context, client->fh);
}
qemu_aio_set_fd_handler(nfs_get_fd(client->context), NULL, NULL, NULL);
nfs_destroy_context(client->context);
}
memset(client, 0, sizeof(NFSClient));
}
static void nfs_file_close(BlockDriverState *bs)
{
NFSClient *client = bs->opaque;
nfs_client_close(client);
}
static int64_t nfs_client_open(NFSClient *client, const char *filename,
int flags, Error **errp)
{
int ret = -EINVAL, i;
struct stat st;
URI *uri;
QueryParams *qp = NULL;
char *file = NULL, *strp = NULL;
uri = uri_parse(filename);
if (!uri) {
error_setg(errp, "Invalid URL specified");
goto fail;
}
strp = strrchr(uri->path, '/');
if (strp == NULL) {
error_setg(errp, "Invalid URL specified");
goto fail;
}
file = g_strdup(strp);
*strp = 0;
client->context = nfs_init_context();
if (client->context == NULL) {
error_setg(errp, "Failed to init NFS context");
goto fail;
}
qp = query_params_parse(uri->query);
for (i = 0; i < qp->n; i++) {
if (!qp->p[i].value) {
error_setg(errp, "Value for NFS parameter expected: %s",
qp->p[i].name);
goto fail;
}
if (!strncmp(qp->p[i].name, "uid", 3)) {
nfs_set_uid(client->context, atoi(qp->p[i].value));
} else if (!strncmp(qp->p[i].name, "gid", 3)) {
nfs_set_gid(client->context, atoi(qp->p[i].value));
} else if (!strncmp(qp->p[i].name, "tcp-syncnt", 10)) {
nfs_set_tcp_syncnt(client->context, atoi(qp->p[i].value));
} else {
error_setg(errp, "Unknown NFS parameter name: %s",
qp->p[i].name);
goto fail;
}
}
ret = nfs_mount(client->context, uri->server, uri->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->has_zero_init = S_ISREG(st.st_mode);
goto out;
fail:
nfs_client_close(client);
out:
if (qp) {
query_params_free(qp);
}
uri_free(uri);
g_free(file);
return ret;
}
static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp) {
NFSClient *client = bs->opaque;
int64_t ret;
QemuOpts *opts;
Error *local_err = NULL;
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return -EINVAL;
}
ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
(flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
errp);
if (ret < 0) {
return ret;
}
bs->total_sectors = ret;
return 0;
}
static int nfs_file_create(const char *url, QEMUOptionParameter *options,
Error **errp)
{
int ret = 0;
int64_t total_size = 0;
NFSClient *client = g_malloc0(sizeof(NFSClient));
/* Read out options */
while (options && options->name) {
if (!strcmp(options->name, "size")) {
total_size = options->value.n;
}
options++;
}
ret = nfs_client_open(client, url, O_CREAT, errp);
if (ret < 0) {
goto out;
}
ret = nfs_ftruncate(client->context, client->fh, total_size);
nfs_client_close(client);
out:
g_free(client);
return ret;
}
static int nfs_has_zero_init(BlockDriverState *bs)
{
NFSClient *client = bs->opaque;
return client->has_zero_init;
}
static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
{
NFSClient *client = bs->opaque;
NFSRPC task = {0};
struct stat st;
task.st = &st;
if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
&task) != 0) {
return -ENOMEM;
}
while (!task.complete) {
nfs_set_events(client);
qemu_aio_wait();
}
return (task.ret < 0 ? task.ret : st.st_blocks * st.st_blksize);
}
static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
{
NFSClient *client = bs->opaque;
return nfs_ftruncate(client->context, client->fh, offset);
}
static BlockDriver bdrv_nfs = {
.format_name = "nfs",
.protocol_name = "nfs",
.instance_size = sizeof(NFSClient),
.bdrv_needs_filename = true,
.bdrv_has_zero_init = nfs_has_zero_init,
.bdrv_get_allocated_file_size = nfs_get_allocated_file_size,
.bdrv_truncate = nfs_file_truncate,
.bdrv_file_open = nfs_file_open,
.bdrv_close = nfs_file_close,
.bdrv_create = nfs_file_create,
.bdrv_co_readv = nfs_co_readv,
.bdrv_co_writev = nfs_co_writev,
.bdrv_co_flush_to_disk = nfs_co_flush,
};
static void nfs_block_init(void)
{
bdrv_register(&bdrv_nfs);
}
block_init(nfs_block_init);
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