On Wed, Feb 28, 2024 at 12:21:21PM -0300, Fabiano Rosas wrote:
> Allow multifd to open file-backed channels. This will be used when
> enabling the mapped-ram migration stream format which expects a
> seekable transport.
>
> The QIOChannel read and write methods will use the preadv/pwritev
> versions which don't update the file offset at each call so we can
> reuse the fd without re-opening for every channel.
>
> Contrary to the socket migration, the file migration doesn't need an
> asynchronous channel creation process, so expose
> multifd_channel_connect() and call it directly.
>
> Note that this is just setup code and multifd cannot yet make use of
> the file channels.
>
> Signed-off-by: Fabiano Rosas <faro...@suse.de>
> ---
> - moved flags change to another patch
> - removed channels_created assert
> ---
> migration/file.c | 41 +++++++++++++++++++++++++++++++++++++++--
> migration/file.h | 4 ++++
> migration/multifd.c | 18 +++++++++++++++---
> migration/multifd.h | 1 +
> 4 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/migration/file.c b/migration/file.c
> index 22d052a71f..83328a7a1b 100644
> --- a/migration/file.c
> +++ b/migration/file.c
> @@ -12,12 +12,17 @@
> #include "channel.h"
> #include "file.h"
> #include "migration.h"
> +#include "multifd.h"
> #include "io/channel-file.h"
> #include "io/channel-util.h"
> #include "trace.h"
>
> #define OFFSET_OPTION ",offset="
>
> +static struct FileOutgoingArgs {
> + char *fname;
> +} outgoing_args;
> +
> /* Remove the offset option from @filespec and return it in @offsetp. */
>
> int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp)
> @@ -37,6 +42,36 @@ int file_parse_offset(char *filespec, uint64_t *offsetp,
> Error **errp)
> return 0;
> }
>
> +void file_cleanup_outgoing_migration(void)
> +{
> + g_free(outgoing_args.fname);
> + outgoing_args.fname = NULL;
> +}
> +
> +bool file_send_channel_create(gpointer opaque, Error **errp)
> +{
> + QIOChannelFile *ioc;
> + int flags = O_WRONLY;
> + bool ret = true;
> +
> + ioc = qio_channel_file_new_path(outgoing_args.fname, flags, 0, errp);
> + if (!ioc) {
> + ret = false;
> + goto out;
> + }
> +
> + multifd_channel_connect(opaque, QIO_CHANNEL(ioc));
> +
> +out:
> + /*
> + * File channel creation is synchronous. However posting this
> + * semaphore here is simpler than adding a special case.
> + */
> + multifd_send_channel_created();
> +
> + return ret;
> +}
> +
> void file_start_outgoing_migration(MigrationState *s,
> FileMigrationArgs *file_args, Error
> **errp)
> {
> @@ -47,12 +82,14 @@ void file_start_outgoing_migration(MigrationState *s,
>
> trace_migration_file_outgoing(filename);
>
> - fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC,
> - 0600, errp);
> + fioc = qio_channel_file_new_path(filename, O_CREAT | O_TRUNC | O_WRONLY,
> + 0660, errp);
It seems this is still leftover?
> if (!fioc) {
> return;
> }
>
> + outgoing_args.fname = g_strdup(filename);
> +
> ioc = QIO_CHANNEL(fioc);
> if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
> return;
> diff --git a/migration/file.h b/migration/file.h
> index 37d6a08bfc..4577f9efdd 100644
> --- a/migration/file.h
> +++ b/migration/file.h
> @@ -9,10 +9,14 @@
> #define QEMU_MIGRATION_FILE_H
>
> #include "qapi/qapi-types-migration.h"
> +#include "io/task.h"
> +#include "channel.h"
>
> void file_start_incoming_migration(FileMigrationArgs *file_args, Error
> **errp);
>
> void file_start_outgoing_migration(MigrationState *s,
> FileMigrationArgs *file_args, Error
> **errp);
> int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp);
> +void file_cleanup_outgoing_migration(void);
> +bool file_send_channel_create(gpointer opaque, Error **errp);
> #endif
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 3574fd3953..f155223303 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -17,6 +17,7 @@
> #include "exec/ramblock.h"
> #include "qemu/error-report.h"
> #include "qapi/error.h"
> +#include "file.h"
> #include "ram.h"
> #include "migration.h"
> #include "migration-stats.h"
> @@ -28,6 +29,7 @@
> #include "threadinfo.h"
> #include "options.h"
> #include "qemu/yank.h"
> +#include "io/channel-file.h"
> #include "io/channel-socket.h"
> #include "yank_functions.h"
>
> @@ -694,6 +696,7 @@ static bool
> multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
> {
> if (p->c) {
> migration_ioc_unregister_yank(p->c);
> + qio_channel_close(p->c, NULL);
s/NULL/&error_abort/?
> object_unref(OBJECT(p->c));
> p->c = NULL;
> }
> @@ -715,6 +718,7 @@ static bool
> multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
>
> static void multifd_send_cleanup_state(void)
> {
> + file_cleanup_outgoing_migration();
> socket_cleanup_outgoing_migration();
> qemu_sem_destroy(&multifd_send_state->channels_created);
> qemu_sem_destroy(&multifd_send_state->channels_ready);
> @@ -977,7 +981,7 @@ static bool multifd_tls_channel_connect(MultiFDSendParams
> *p,
> return true;
> }
>
> -static void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc)
> +void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc)
> {
> qio_channel_set_delay(ioc, false);
>
> @@ -1045,9 +1049,14 @@ out:
> error_free(local_err);
> }
>
> -static void multifd_new_send_channel_create(gpointer opaque)
> +static bool multifd_new_send_channel_create(gpointer opaque, Error **errp)
> {
> + if (!multifd_use_packets()) {
> + return file_send_channel_create(opaque, errp);
> + }
> +
> socket_send_channel_create(multifd_new_send_channel_async, opaque);
> + return true;
> }
>
> bool multifd_send_setup(void)
> @@ -1096,7 +1105,10 @@ bool multifd_send_setup(void)
> p->page_size = qemu_target_page_size();
> p->page_count = page_count;
> p->write_flags = 0;
> - multifd_new_send_channel_create(p);
> +
> + if (!multifd_new_send_channel_create(p, &local_err)) {
> + return -1;
"-1" is unfortunately a "true"!..
> + }
> }
>
> /*
> diff --git a/migration/multifd.h b/migration/multifd.h
> index 1d8bbaf96b..db8887f088 100644
> --- a/migration/multifd.h
> +++ b/migration/multifd.h
> @@ -227,5 +227,6 @@ static inline void
> multifd_send_prepare_header(MultiFDSendParams *p)
> p->iovs_num++;
> }
>
> +void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc);
>
> #endif
> --
> 2.35.3
>
--
Peter Xu
