It's not too surprising when a user specifies the backing file relative
to the current working directory instead of the top layer image. This
causes error when they differ. Though the error message has enough
information to infer the fact about the misunderstanding, it is better
if we document this explicitly, so that users don't have to learn from
mistakes.
Signed-off-by: Fam Zheng <famz@redhat.com>
---
v2: Improve wording. [Eric]
---
qemu-img.texi | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/qemu-img.texi b/qemu-img.texi
index 72dabd6b3e..90c7eab4a8 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -244,6 +244,9 @@ only the differences from @var{backing_file}. No size needs to be specified in
this case. @var{backing_file} will never be modified unless you use the
@code{commit} monitor command (or qemu-img commit).
+If a relative path name is given, the backing file is looked up relative to
+the directory containing @var{filename}.
+
Note that a given backing file will be opened to check that it is valid. Use
the @code{-u} option to enable unsafe backing file mode, which means that the
image will be created even if the associated backing file cannot be opened. A
@@ -343,6 +346,9 @@ created as a copy on write image of the specified base image; the
@var{backing_file} should have the same content as the input's base image,
however the path, image format, etc may differ.
+If a relative path name is given, the backing file is looked up relative to
+the directory containing @var{output_filename}.
+
If the @code{-n} option is specified, the target volume creation will be
skipped. This is useful for formats such as @code{rbd} if the target
volume has already been created with site specific options that cannot
@@ -490,6 +496,9 @@ The backing file is changed to @var{backing_file} and (if the image format of
string), then the image is rebased onto no backing file (i.e. it will exist
independently of any backing file).
+If a relative path name is given, the backing file is looked up relative to
+the directory containing @var{filename}.
+
@var{cache} specifies the cache mode to be used for @var{filename}, whereas
@var{src_cache} specifies the cache mode for reading backing files.
--
2.13.3
On 08/04/2017 09:36 AM, Fam Zheng wrote: > It's not too surprising when a user specifies the backing file relative > to the current working directory instead of the top layer image. This > causes error when they differ. Though the error message has enough > information to infer the fact about the misunderstanding, it is better > if we document this explicitly, so that users don't have to learn from > mistakes. > > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > v2: Improve wording. [Eric] > --- > qemu-img.texi | 9 +++++++++ > 1 file changed, 9 insertions(+) Reviewed-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
On Fri, Aug 04, 2017 at 10:36:58PM +0800, Fam Zheng wrote: > It's not too surprising when a user specifies the backing file relative > to the current working directory instead of the top layer image. This > causes error when they differ. Though the error message has enough > information to infer the fact about the misunderstanding, it is better > if we document this explicitly, so that users don't have to learn from > mistakes. > > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > v2: Improve wording. [Eric] > --- > qemu-img.texi | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/qemu-img.texi b/qemu-img.texi > index 72dabd6b3e..90c7eab4a8 100644 > --- a/qemu-img.texi > +++ b/qemu-img.texi > @@ -244,6 +244,9 @@ only the differences from @var{backing_file}. No size needs to be specified in > this case. @var{backing_file} will never be modified unless you use the > @code{commit} monitor command (or qemu-img commit). > > +If a relative path name is given, the backing file is looked up relative to > +the directory containing @var{filename}. > + > Note that a given backing file will be opened to check that it is valid. Use > the @code{-u} option to enable unsafe backing file mode, which means that the > image will be created even if the associated backing file cannot be opened. A > @@ -343,6 +346,9 @@ created as a copy on write image of the specified base image; the > @var{backing_file} should have the same content as the input's base image, > however the path, image format, etc may differ. > > +If a relative path name is given, the backing file is looked up relative to > +the directory containing @var{output_filename}. > + > If the @code{-n} option is specified, the target volume creation will be > skipped. This is useful for formats such as @code{rbd} if the target > volume has already been created with site specific options that cannot > @@ -490,6 +496,9 @@ The backing file is changed to @var{backing_file} and (if the image format of > string), then the image is rebased onto no backing file (i.e. it will exist > independently of any backing file). > > +If a relative path name is given, the backing file is looked up relative to > +the directory containing @var{filename}. > + > @var{cache} specifies the cache mode to be used for @var{filename}, whereas > @var{src_cache} specifies the cache mode for reading backing files. > > -- > 2.13.3 > > Reviewed-by: Jeff Cody <jcody@redhat.com>
On Fri, Aug 04, 2017 at 10:36:58PM +0800, Fam Zheng wrote: > It's not too surprising when a user specifies the backing file relative > to the current working directory instead of the top layer image. This > causes error when they differ. Though the error message has enough > information to infer the fact about the misunderstanding, it is better > if we document this explicitly, so that users don't have to learn from > mistakes. > > Signed-off-by: Fam Zheng <famz@redhat.com> > > --- > v2: Improve wording. [Eric] > --- > qemu-img.texi | 9 +++++++++ > 1 file changed, 9 insertions(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
On Fri, 08/04 22:36, Fam Zheng wrote: > It's not too surprising when a user specifies the backing file relative > to the current working directory instead of the top layer image. This > causes error when they differ. Though the error message has enough > information to infer the fact about the misunderstanding, it is better > if we document this explicitly, so that users don't have to learn from > mistakes. Gentle ping as a reminder for 2.11, as 2.10 is now out of door. Fam
Am 04.08.2017 um 16:36 hat Fam Zheng geschrieben: > It's not too surprising when a user specifies the backing file relative > to the current working directory instead of the top layer image. This > causes error when they differ. Though the error message has enough > information to infer the fact about the misunderstanding, it is better > if we document this explicitly, so that users don't have to learn from > mistakes. > > Signed-off-by: Fam Zheng <famz@redhat.com> Thanks, applied to the block branch. Kevin
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