s390x/pci: let pci devices start in configured mode

[mirror_qemu.git] / qemu-img.texi

diff --git a/qemu-img.texi b/qemu-img.texi
index 72dabd6b3e632a3a74c8f8f8ce185b80239df34d..fdcf120f360247afb6ed9699ec9feffb9e4ab40a 100644 (file)
--- 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
@@ -271,11 +274,10 @@ If the backing chain of the given image file @var{filename} has more than one
 layer, the backing file into which the changes will be committed may be
 specified as @var{base} (which has to be part of @var{filename}'s backing
 chain). If @var{base} is not specified, the immediate backing file of the top
-image (which is @var{filename}) will be used. For reasons of consistency,
-explicitly specifying @var{base} will always imply @code{-d} (since emptying an
-image after committing to an indirect backing file would lead to different data
-being read from the image due to content in the intermediate backing chain
-overruling the commit target).
+image (which is @var{filename}) will be used. Note that after a commit operation
+all images between @var{base} and the top image will be invalid and may return
+garbage data when read. For this reason, @code{-b} implies @code{-d} (so that
+the top image stays valid).
 
 @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
 
@@ -343,6 +345,9 @@ 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 +495,9 @@ 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.
 
@@ -536,7 +544,7 @@ qemu-img rebase -b base.img diff.qcow2
 At this point, @code{modified.img} can be discarded, since
 @code{base.img + diff.qcow2} contains the same information.
 
-@item resize [--preallocation=@var{prealloc}] @var{filename} [+ | -]@var{size}
+@item resize [--shrink] [--preallocation=@var{prealloc}] @var{filename} [+ | -]@var{size}
 
 Change the disk image as if it had been created with @var{size}.
 
@@ -544,6 +552,10 @@ Before using this command to shrink a disk image, you MUST use file system and
 partitioning tools inside the VM to reduce allocated file systems and partition
 sizes accordingly.  Failure to do so will result in data loss!
 
+When shrinking images, the @code{--shrink} option must be given. This informs
+qemu-img that the user acknowledges all loss of data beyond the truncated
+image's end.
+
 After using this command to grow a disk image, you must use file system and
 partitioning tools inside the VM to actually begin using the new space on the
 device.