From: Nikolay Borisov <nbori...@suse.com>
The upcoming 'fixed-ram' feature will require qemu to write data to
(and restore from) specific offsets of the migration file.
Add a minimal implementation of pwritev/preadv and expose them via the
io_pwritev and io_preadv interfaces.
Signed-off-by: Nikolay Borisov <nbori...@suse.com>
Signed-off-by: Fabiano Rosas <faro...@suse.de>
Reviewed-by: Daniel P. Berrangé <berra...@redhat.com>
---
io/channel-file.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/io/channel-file.c b/io/channel-file.c
index f91bf6db1c..731a2fbc68 100644
--- a/io/channel-file.c
+++ b/io/channel-file.c
@@ -146,6 +146,56 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc,
return ret;
}
+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;
+}
+
static int qio_channel_file_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
@@ -231,6 +281,8 @@ static void qio_channel_file_class_init(ObjectClass *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;
+ ioc_klass->io_pwritev = qio_channel_file_pwritev;
+ ioc_klass->io_preadv = qio_channel_file_preadv;
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;
--
2.35.3
