qemu-img.texi | 9 +++++++++ 1 file changed, 9 insertions(+)
Signed-off-by: Fam Zheng <famz@redhat.com>
---
v2: - "code{qemu-img}". [Kashyap, Eric]
- "etc.." -> "etc.".
---
qemu-img.texi | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/qemu-img.texi b/qemu-img.texi
index fdcf120f36..6b9f9adfc8 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -57,6 +57,15 @@ exclusive with the @var{-O} parameters. It is currently required to also use
the @var{-n} parameter to skip image creation. This restriction may be relaxed
in a future release.
+@item --force-share (-U)
+
+If specified, @code{qemu-img} will open the image with shared permissions,
+which makes it less likely to conflict with a running guest's permissions due
+to image locking. For example, this can be used to get the image information
+(with 'info' subcommand) when the image is used by a running guest. Note that
+this could produce inconsistent result because of concurrent metadata changes,
+etc.
+
@item fmt
is the disk image format. It is guessed automatically in most cases. See below
for a description of the supported disk formats.
--
2.14.3
On Fri, Dec 08, 2017 at 09:44:56AM +0800, Fam Zheng wrote: > +@item --force-share (-U) > + > +If specified, @code{qemu-img} will open the image with shared permissions, > +which makes it less likely to conflict with a running guest's permissions due > +to image locking. For example, this can be used to get the image information > +(with 'info' subcommand) when the image is used by a running guest. Note that > +this could produce inconsistent result because of concurrent metadata changes, > +etc. The documentation isn't clear on whether read-write is supported or just read-only. Also, should it be declared a legacy option right away to discourage use in new software?
Am 08.12.2017 um 10:54 hat Stefan Hajnoczi geschrieben: > On Fri, Dec 08, 2017 at 09:44:56AM +0800, Fam Zheng wrote: > > +@item --force-share (-U) > > + > > +If specified, @code{qemu-img} will open the image with shared permissions, > > +which makes it less likely to conflict with a running guest's permissions due > > +to image locking. For example, this can be used to get the image information > > +(with 'info' subcommand) when the image is used by a running guest. Note that > > +this could produce inconsistent result because of concurrent metadata changes, > > +etc. > > The documentation isn't clear on whether read-write is supported or just > read-only. > > Also, should it be declared a legacy option right away to discourage > use in new software? I don't think this is a legacy option. As long you know what you're doing, using it is fine. Kevin
On Fri, 12/08 09:54, Stefan Hajnoczi wrote: > On Fri, Dec 08, 2017 at 09:44:56AM +0800, Fam Zheng wrote: > > +@item --force-share (-U) > > + > > +If specified, @code{qemu-img} will open the image with shared permissions, > > +which makes it less likely to conflict with a running guest's permissions due > > +to image locking. For example, this can be used to get the image information > > +(with 'info' subcommand) when the image is used by a running guest. Note that > > +this could produce inconsistent result because of concurrent metadata changes, > > +etc. > > The documentation isn't clear on whether read-write is supported or just > read-only. block.c will emit an error if used with read-write. I will add a sentence for that. Fam
On Fri, Dec 08, 2017 at 09:44:56AM +0800, Fam Zheng wrote: > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > v2: - "code{qemu-img}". [Kashyap, Eric] > - "etc.." -> "etc.". > --- > qemu-img.texi | 9 +++++++++ > 1 file changed, 9 insertions(+) Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> [...] -- /kashyap
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