qemu/io/channel-file.c
Fabiano Rosas c05dfcb7f2 io: fsync before closing a file channel
Make sure the data is flushed to disk before closing file
channels. This is to ensure data is on disk and not lost in the event
of a host crash.

This is currently being implemented to affect the migration code when
migrating to a file, but all QIOChannelFile users should benefit from
the change.

Reviewed-by: "Daniel P. Berrangé" <berrange@redhat.com>
Acked-by: "Daniel P. Berrangé" <berrange@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240229153017.2221-6-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-03-01 15:42:04 +08:00

316 lines
8.9 KiB
C

/*
* QEMU I/O channels files driver
*
* Copyright (c) 2015 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "io/channel-file.h"
#include "io/channel-util.h"
#include "io/channel-watch.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/sockets.h"
#include "trace.h"
QIOChannelFile *
qio_channel_file_new_fd(int fd)
{
QIOChannelFile *ioc;
ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
ioc->fd = fd;
if (lseek(fd, 0, SEEK_CUR) != (off_t)-1) {
qio_channel_set_feature(QIO_CHANNEL(ioc), QIO_CHANNEL_FEATURE_SEEKABLE);
}
trace_qio_channel_file_new_fd(ioc, fd);
return ioc;
}
QIOChannelFile *
qio_channel_file_new_path(const char *path,
int flags,
mode_t mode,
Error **errp)
{
QIOChannelFile *ioc;
ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
ioc->fd = qemu_open_old(path, flags, mode);
if (ioc->fd < 0) {
object_unref(OBJECT(ioc));
error_setg_errno(errp, errno,
"Unable to open %s", path);
return NULL;
}
if (lseek(ioc->fd, 0, SEEK_CUR) != (off_t)-1) {
qio_channel_set_feature(QIO_CHANNEL(ioc), QIO_CHANNEL_FEATURE_SEEKABLE);
}
trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
return ioc;
}
static void qio_channel_file_init(Object *obj)
{
QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
ioc->fd = -1;
}
static void qio_channel_file_finalize(Object *obj)
{
QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
if (ioc->fd != -1) {
qemu_close(ioc->fd);
ioc->fd = -1;
}
}
static ssize_t qio_channel_file_readv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
int flags,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = readv(fioc->fd, iov, niov);
if (ret < 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno,
"Unable to read from file");
return -1;
}
return ret;
}
static ssize_t qio_channel_file_writev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
int flags,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = writev(fioc->fd, iov, niov);
if (ret <= 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno,
"Unable to write to file");
return -1;
}
return ret;
}
#ifdef CONFIG_PREADV
static ssize_t qio_channel_file_preadv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = preadv(fioc->fd, iov, niov, offset);
if (ret < 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno, "Unable to read from file");
return -1;
}
return ret;
}
static ssize_t qio_channel_file_pwritev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = pwritev(fioc->fd, iov, niov, offset);
if (ret <= 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno, "Unable to write to file");
return -1;
}
return ret;
}
#endif /* CONFIG_PREADV */
static int qio_channel_file_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
{
#ifdef WIN32
/* not implemented */
error_setg_errno(errp, errno, "Failed to set FD nonblocking");
return -1;
#else
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
if (!g_unix_set_fd_nonblocking(fioc->fd, !enabled, NULL)) {
error_setg_errno(errp, errno, "Failed to set FD nonblocking");
return -1;
}
return 0;
#endif
}
static off_t qio_channel_file_seek(QIOChannel *ioc,
off_t offset,
int whence,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
off_t ret;
ret = lseek(fioc->fd, offset, whence);
if (ret == (off_t)-1) {
error_setg_errno(errp, errno,
"Unable to seek to offset %lld whence %d in file",
(long long int)offset, whence);
return -1;
}
return ret;
}
static int qio_channel_file_close(QIOChannel *ioc,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
if (qemu_fdatasync(fioc->fd) < 0) {
error_setg_errno(errp, errno,
"Unable to synchronize file data with storage device");
return -1;
}
if (qemu_close(fioc->fd) < 0) {
error_setg_errno(errp, errno,
"Unable to close file");
return -1;
}
fioc->fd = -1;
return 0;
}
static void qio_channel_file_set_aio_fd_handler(QIOChannel *ioc,
AioContext *read_ctx,
IOHandler *io_read,
AioContext *write_ctx,
IOHandler *io_write,
void *opaque)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
qio_channel_util_set_aio_fd_handler(fioc->fd, read_ctx, io_read,
fioc->fd, write_ctx, io_write,
opaque);
}
static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
GIOCondition condition)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
return qio_channel_create_fd_watch(ioc,
fioc->fd,
condition);
}
static void qio_channel_file_class_init(ObjectClass *klass,
void *class_data G_GNUC_UNUSED)
{
QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
ioc_klass->io_writev = qio_channel_file_writev;
ioc_klass->io_readv = qio_channel_file_readv;
ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
#ifdef CONFIG_PREADV
ioc_klass->io_pwritev = qio_channel_file_pwritev;
ioc_klass->io_preadv = qio_channel_file_preadv;
#endif
ioc_klass->io_seek = qio_channel_file_seek;
ioc_klass->io_close = qio_channel_file_close;
ioc_klass->io_create_watch = qio_channel_file_create_watch;
ioc_klass->io_set_aio_fd_handler = qio_channel_file_set_aio_fd_handler;
}
static const TypeInfo qio_channel_file_info = {
.parent = TYPE_QIO_CHANNEL,
.name = TYPE_QIO_CHANNEL_FILE,
.instance_size = sizeof(QIOChannelFile),
.instance_init = qio_channel_file_init,
.instance_finalize = qio_channel_file_finalize,
.class_init = qio_channel_file_class_init,
};
static void qio_channel_file_register_types(void)
{
type_register_static(&qio_channel_file_info);
}
type_init(qio_channel_file_register_types);