The synth fsdriver never got used for anything else but the
QTest testcase for VirtIO 9P. And even there, QTest directly
uses -fsdev synth and -device virtio-9p-{pci|device}.

Signed-off-by: Greg Kurz <groug@kaod.org>
---

This should be Cc'd to libvir-list@redhat.com according to MAINTAINERS,
but libvirt doesn't know about -virtfs_synth, so I choose to not spam :)
---
 qemu-deprecated.texi |    4 ++++
 qemu-options.hx      |    3 ++-
 vl.c                 |    5 +++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index 842e71b11dcc..f0ff065e7dc1 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -72,6 +72,10 @@ backend settings instead of environment variables.  To ease migration to
 the new format, the ``-audiodev-help'' option can be used to convert
 the current values of the environment variables to ``-audiodev'' options.
 
+@subsection -virtfs_synth (since 4.1)
+
+The ``-virtfs_synth'' argument is now deprecated with no replacement.
+
 @section QEMU Machine Protocol (QMP) commands
 
 @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
diff --git a/qemu-options.hx b/qemu-options.hx
index 51802cbb266a..9c5cc2e6bf70 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1368,7 +1368,8 @@ DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
 STEXI
 @item -virtfs_synth
 @findex -virtfs_synth
-Create synthetic file system image
+Create synthetic file system image. Note that this option is deprecated with
+no replacement.
 ETEXI
 
 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
diff --git a/vl.c b/vl.c
index d9fea0a11966..c010cb3e98df 100644
--- a/vl.c
+++ b/vl.c
@@ -3507,6 +3507,11 @@ int main(int argc, char **argv, char **envp)
                 QemuOpts *fsdev;
                 QemuOpts *device;
 
+                warn_report("The -virtfs_synth option is deprecated and will "
+                            "be removed soon. If the -virtfs_synth option is "
+                            "still useful for you, please send a mail to "
+                            "qemu-devel@nongnu.org with your usecase.");
+
                 fsdev = qemu_opts_create(qemu_find_opts("fsdev"), "v_synth",
                                          1, NULL);
                 if (!fsdev) {

On 07/05/2019 10.45, Greg Kurz wrote:
> The synth fsdriver never got used for anything else but the
> QTest testcase for VirtIO 9P. And even there, QTest directly
> uses -fsdev synth and -device virtio-9p-{pci|device}.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
> 
> This should be Cc'd to libvir-list@redhat.com according to MAINTAINERS,
> but libvirt doesn't know about -virtfs_synth, so I choose to not spam :)
> ---
>  qemu-deprecated.texi |    4 ++++
>  qemu-options.hx      |    3 ++-
>  vl.c                 |    5 +++++
>  3 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
> index 842e71b11dcc..f0ff065e7dc1 100644
> --- a/qemu-deprecated.texi
> +++ b/qemu-deprecated.texi
> @@ -72,6 +72,10 @@ backend settings instead of environment variables.  To ease migration to
>  the new format, the ``-audiodev-help'' option can be used to convert
>  the current values of the environment variables to ``-audiodev'' options.
>  
> +@subsection -virtfs_synth (since 4.1)
> +
> +The ``-virtfs_synth'' argument is now deprecated with no replacement.
> +
>  @section QEMU Machine Protocol (QMP) commands
>  
>  @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 51802cbb266a..9c5cc2e6bf70 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1368,7 +1368,8 @@ DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
>  STEXI
>  @item -virtfs_synth
>  @findex -virtfs_synth
> -Create synthetic file system image
> +Create synthetic file system image. Note that this option is deprecated with
> +no replacement.
>  ETEXI
>  
>  DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
> diff --git a/vl.c b/vl.c
> index d9fea0a11966..c010cb3e98df 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3507,6 +3507,11 @@ int main(int argc, char **argv, char **envp)
>                  QemuOpts *fsdev;
>                  QemuOpts *device;
>  
> +                warn_report("The -virtfs_synth option is deprecated and will "
> +                            "be removed soon. If the -virtfs_synth option is "
> +                            "still useful for you, please send a mail to "
> +                            "qemu-devel@nongnu.org with your usecase.");
> +
>                  fsdev = qemu_opts_create(qemu_find_opts("fsdev"), "v_synth",
>                                           1, NULL);
>                  if (!fsdev) {

Do you plan to only deprecate the -virtfs_synth option, or also "-fsdev
synth", i.e. the whole "synth" driver? In the first case, I think you
should point the users to use "-fsdev synth" instead of saying "with no
replacement". In the second case, I think you should declare "-fsdev
synth" in the documentation, too.

 Thomas

On Wed, 8 May 2019 10:26:53 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 07/05/2019 10.45, Greg Kurz wrote:
> > The synth fsdriver never got used for anything else but the
> > QTest testcase for VirtIO 9P. And even there, QTest directly
> > uses -fsdev synth and -device virtio-9p-{pci|device}.
> > 
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> > ---
> > 
> > This should be Cc'd to libvir-list@redhat.com according to MAINTAINERS,
> > but libvirt doesn't know about -virtfs_synth, so I choose to not spam :)
> > ---
> >  qemu-deprecated.texi |    4 ++++
> >  qemu-options.hx      |    3 ++-
> >  vl.c                 |    5 +++++
> >  3 files changed, 11 insertions(+), 1 deletion(-)
> > 
> > diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
> > index 842e71b11dcc..f0ff065e7dc1 100644
> > --- a/qemu-deprecated.texi
> > +++ b/qemu-deprecated.texi
> > @@ -72,6 +72,10 @@ backend settings instead of environment variables.  To ease migration to
> >  the new format, the ``-audiodev-help'' option can be used to convert
> >  the current values of the environment variables to ``-audiodev'' options.
> >  
> > +@subsection -virtfs_synth (since 4.1)
> > +
> > +The ``-virtfs_synth'' argument is now deprecated with no replacement.
> > +
> >  @section QEMU Machine Protocol (QMP) commands
> >  
> >  @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 51802cbb266a..9c5cc2e6bf70 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -1368,7 +1368,8 @@ DEF("virtfs_synth", 0, QEMU_OPTION_virtfs_synth,
> >  STEXI
> >  @item -virtfs_synth
> >  @findex -virtfs_synth
> > -Create synthetic file system image
> > +Create synthetic file system image. Note that this option is deprecated with
> > +no replacement.
> >  ETEXI
> >  
> >  DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
> > diff --git a/vl.c b/vl.c
> > index d9fea0a11966..c010cb3e98df 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -3507,6 +3507,11 @@ int main(int argc, char **argv, char **envp)
> >                  QemuOpts *fsdev;
> >                  QemuOpts *device;
> >  
> > +                warn_report("The -virtfs_synth option is deprecated and will "
> > +                            "be removed soon. If the -virtfs_synth option is "
> > +                            "still useful for you, please send a mail to "
> > +                            "qemu-devel@nongnu.org with your usecase.");
> > +
> >                  fsdev = qemu_opts_create(qemu_find_opts("fsdev"), "v_synth",
> >                                           1, NULL);
> >                  if (!fsdev) {  
> 
> Do you plan to only deprecate the -virtfs_synth option, or also "-fsdev
> synth", i.e. the whole "synth" driver? In the first case, I think you
> should point the users to use "-fsdev synth" instead of saying "with no
> replacement".

The plan is to remove -virtfs_synth only. You're right, I'll point users
to use "-fsdev synth" and "-device virtio-9p" instead.

> In the second case, I think you should declare "-fsdev
> synth" in the documentation, too.
> 
>  Thomas