On Thu, May 23, 2024 at 04:05:31PM -0300, Fabiano Rosas wrote:
> When the "file:" migration support was added we missed the special
> case in the qemu_open_old implementation that allows for a particular
> file name format to be used to refer to a set of file descriptors that
> have been previously provided to QEMU via the add-fd QMP command.
>
> When using this fdset feature, we should not truncate the migration
> file because being given an fd means that the management layer is in
> control of the file and will likely already have some data written to
> it. This is further indicated by the presence of the 'offset'
> argument, which indicates the start of the region where QEMU is
> allowed to write.
>
> Fix the issue by replacing the O_TRUNC flag on open by an ftruncate
> call, which will take the offset into consideration.
>
> Fixes: 385f510df5 ("migration: file URI offset")
> Suggested-by: Daniel P. Berrangé <berra...@redhat.com>
> Signed-off-by: Fabiano Rosas <faro...@suse.de>
Reviewed-by: Peter Xu <pet...@redhat.com>
Right below the change, did we forget to free the ioc if
qio_channel_io_seek() failed?
> ---
> migration/file.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/migration/file.c b/migration/file.c
> index ab18ba505a..ba5b5c44ff 100644
> --- a/migration/file.c
> +++ b/migration/file.c
> @@ -84,12 +84,19 @@ 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_WRONLY, 0600,
> errp);
> if (!fioc) {
> return;
> }
>
> + if (ftruncate(fioc->fd, offset)) {
> + error_setg_errno(errp, errno,
> + "failed to truncate migration file to offset %"
> PRIx64,
> + offset);
> + object_unref(OBJECT(fioc));
> + return;
> + }
> +
> outgoing_args.fname = g_strdup(filename);
>
> ioc = QIO_CHANNEL(fioc);
> --
> 2.35.3
>
--
Peter Xu
