target-arm/arm-powerctl: wake up sleeping CPUs

[qemu.git] / qemu-img.texi

diff --git a/qemu-img.texi b/qemu-img.texi
index 688b28d87b8056a97fac76ad13548e27dfc9e664..174aae38b7511eef572a8d1e186b3876743e284f 100644 (file)
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -1,6 +1,6 @@
 @example
 @c man begin SYNOPSIS
 @example
 @c man begin SYNOPSIS

-usage: qemu-img command [command options]
+@command{qemu-img} [@var{standard} @var{options}] @var{command} [@var{command} @var{options}]

 @c man end
 @end example
 
 @c man end
 @end example
 


@@ -16,6 +16,17 @@ inconsistent state.
 
 @c man begin OPTIONS
 
 
 @c man begin OPTIONS
 

+Standard options:
+@table @option
+@item -h, --help
+Display this help and exit
+@item -V, --version
+Display version information and exit
+@item -T, --trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
+@findex --trace
+@include qemu-option-trace.texi
+@end table
+

 The following commands are supported:
 
 @include qemu-img-cmds.texi
 The following commands are supported:
 
 @include qemu-img-cmds.texi


@@ -24,6 +35,20 @@ Command parameters:
 @table @var
 @item filename
  is a disk image filename
 @table @var
 @item filename
  is a disk image filename

+
+@item --object @var{objectdef}
+
+is a QEMU user creatable object definition. See the @code{qemu(1)} manual
+page for a description of the object properties. The most common object
+type is a @code{secret}, which is used to supply passwords and/or encryption
+keys.
+
+@item --image-opts
+
+Indicates that the @var{filename} parameter is to be interpreted as a
+full option string, not a plain filename. This parameter is mutually
+exclusive with the @var{-f} and @var{-F} parameters.
+

 @item fmt
 is the disk image format. It is guessed automatically in most cases. See below
 for a description of the supported disk formats.
 @item fmt
 is the disk image format. It is guessed automatically in most cases. See below
 for a description of the supported disk formats.


@@ -73,8 +98,9 @@ specifies the cache mode that should be used with the (destination) file. See
 the documentation of the emulator's @code{-drive cache=...} option for allowed
 values.
 @item -T @var{src_cache}
 the documentation of the emulator's @code{-drive cache=...} option for allowed
 values.
 @item -T @var{src_cache}

-in contrast specifies the cache mode that should be used with the source
-file(s).
+specifies the cache mode that should be used with the source file(s). See
+the documentation of the emulator's @code{-drive cache=...} option for allowed
+values.

 @end table
 
 Parameters to snapshot subcommand:
 @end table
 
 Parameters to snapshot subcommand:


@@ -102,7 +128,7 @@ First image format
 @item -F
 Second image format
 @item -s
 @item -F
 Second image format
 @item -s

-Strict mode - fail on on different image size or sector allocation
+Strict mode - fail on different image size or sector allocation

 @end table
 
 Parameters to convert subcommand:
 @end table
 
 Parameters to convert subcommand:


@@ -113,9 +139,49 @@ Parameters to convert subcommand:
 Skip the creation of the target volume
 @end table
 
 Skip the creation of the target volume
 @end table
 

+Parameters to dd subcommand:
+
+@table @option
+
+@item bs=@var{block_size}
+defines the block size
+@item count=@var{blocks}
+sets the number of input blocks to copy
+@item if=@var{input}
+sets the input file
+@item of=@var{output}
+sets the output file
+@item skip=@var{blocks}
+sets the number of input blocks to skip
+@end table
+

 Command description:
 
 @table @option
 Command description:
 
 @table @option

+@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [--flush-interval=@var{flush_interval}] [-n] [--no-drain] [-o @var{offset}] [--pattern=@var{pattern}] [-q] [-s @var{buffer_size}] [-S @var{step_size}] [-t @var{cache}] [-w] @var{filename}
+
+Run a simple sequential I/O benchmark on the specified image. If @code{-w} is
+specified, a write test is performed, otherwise a read test is performed.
+
+A total number of @var{count} I/O requests is performed, each @var{buffer_size}
+bytes in size, and with @var{depth} requests in parallel. The first request
+starts at the position given by @var{offset}, each following request increases
+the current position by @var{step_size}. If @var{step_size} is not given,
+@var{buffer_size} is used for its value.
+
+If @var{flush_interval} is specified for a write test, the request queue is
+drained and a flush is issued before new writes are made whenever the number of
+remaining requests is a multiple of @var{flush_interval}. If additionally
+@code{--no-drain} is specified, a flush is issued without draining the request
+queue first.
+
+If @code{-n} is specified, the native AIO backend is used if possible. On
+Linux, this option only works if @code{-t none} or @code{-t directsync} is
+specified as well.
+
+For write tests, by default a buffer filled with zeros is written. This can be
+overridden with a pattern byte specified by @var{pattern}.
+

 @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename}
 
 Perform a consistency check on the disk image @var{filename}. The command can
 @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename}
 
 Perform a consistency check on the disk image @var{filename}. The command can


@@ -166,7 +232,7 @@ this case. @var{backing_file} will never be modified unless you use the
 The size can also be specified using the @var{size} option with @code{-o},
 it doesn't need to be specified separately in this case.
 
 The size can also be specified using the @var{size} option with @code{-o},
 it doesn't need to be specified separately in this case.
 

-@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
+@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{base}] [-d] [-p] @var{filename}

 
 Commit the changes recorded in @var{filename} in its base image or backing file.
 If the backing file is smaller than the snapshot, then the backing file will be
 
 Commit the changes recorded in @var{filename} in its base image or backing file.
 If the backing file is smaller than the snapshot, then the backing file will be


@@ -175,6 +241,20 @@ the backing file, the backing file will not be truncated.  If you want the
 backing file to match the size of the smaller snapshot, you can safely truncate
 it yourself once the commit operation successfully completes.
 
 backing file to match the size of the smaller snapshot, you can safely truncate
 it yourself once the commit operation successfully completes.
 

+The image @var{filename} is emptied after the operation has succeeded. If you do
+not need @var{filename} afterwards and intend to drop it, you may skip emptying
+@var{filename} by specifying the @code{-d} flag.
+
+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).
+

 @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
 
 Check if two images have the same content. You can compare images with
 @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
 
 Check if two images have the same content. You can compare images with


@@ -227,8 +307,8 @@ compression is read-only. It means that if a compressed sector is
 rewritten, then it is rewritten as uncompressed data.
 
 Image conversion is also useful to get smaller image when using a
 rewritten, then it is rewritten as uncompressed data.
 
 Image conversion is also useful to get smaller image when using a

-growable format such as @code{qcow} or @code{cow}: the empty sectors
-are detected and suppressed from the destination image.
+growable format such as @code{qcow}: the empty sectors are detected and
+suppressed from the destination image.

 
 @var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
 that must contain only zeros for qemu-img to create a sparse image during
 
 @var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
 that must contain only zeros for qemu-img to create a sparse image during


@@ -246,6 +326,17 @@ skipped. This is useful for formats such as @code{rbd} if the target
 volume has already been created with site specific options that cannot
 be supplied through qemu-img.
 
 volume has already been created with site specific options that cannot
 be supplied through qemu-img.
 

+@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output}
+
+Dd copies from @var{input} file to @var{output} file converting it from
+@var{fmt} format to @var{output_fmt} format.
+
+The data is by default read and written using blocks of 512 bytes but can be
+modified by specifying @var{block_size}. If count=@var{blocks} is specified
+dd will stop reading input after reading @var{blocks} input blocks.
+
+The size syntax is similar to dd(1)'s size syntax.
+

 @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}
 
 Give information about the disk image @var{filename}. Use it in
 @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}
 
 Give information about the disk image @var{filename}. Use it in


@@ -340,7 +431,7 @@ string), then the image is rebased onto no backing file (i.e. it will exist
 independently of any backing file).
 
 @var{cache} specifies the cache mode to be used for @var{filename}, whereas
 independently of any backing file).
 
 @var{cache} specifies the cache mode to be used for @var{filename}, whereas

-@var{src_cache} specifies the cache mode for reading the new backing file.
+@var{src_cache} specifies the cache mode for reading backing files.

 
 There are two different modes in which @code{rebase} can operate:
 @table @option
 
 There are two different modes in which @code{rebase} can operate:
 @table @option


@@ -397,7 +488,7 @@ 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.
 
 partitioning tools inside the VM to actually begin using the new space on the
 device.
 

-@item amend [-f @var{fmt}] -o @var{options} @var{filename}
+@item amend [-p] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}

 
 Amends the image format specific @var{options} for the image file
 @var{filename}. Not all file formats support this operation.
 
 Amends the image format specific @var{options} for the image file
 @var{filename}. Not all file formats support this operation.


@@ -418,6 +509,15 @@ Linux or NTFS on Windows), then only the written sectors will reserve
 space. Use @code{qemu-img info} to know the real size used by the
 image or @code{ls -ls} on Unix/Linux.
 
 space. Use @code{qemu-img info} to know the real size used by the
 image or @code{ls -ls} on Unix/Linux.
 

+Supported options:
+@table @code
+@item preallocation
+Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).
+@code{falloc} mode preallocates space for image by calling posix_fallocate().
+@code{full} mode preallocates space for image by writing zeros to underlying
+storage.
+@end table
+

 @item qcow2
 QEMU image format, the most versatile format. Use it to have smaller
 images (useful if your filesystem does not supports holes, for example
 @item qcow2
 QEMU image format, the most versatile format. Use it to have smaller
 images (useful if your filesystem does not supports holes, for example


@@ -466,9 +566,11 @@ sizes can improve the image file size whereas larger cluster sizes generally
 provide better performance.
 
 @item preallocation
 provide better performance.
 
 @item preallocation

-Preallocation mode (allowed values: off, metadata). An image with preallocated
-metadata is initially larger but can improve performance when the image needs
-to grow.
+Preallocation mode (allowed values: @code{off}, @code{metadata}, @code{falloc},
+@code{full}). An image with preallocated metadata is initially larger but can
+improve performance when the image needs to grow. @code{falloc} and @code{full}
+preallocations are like the same options of @code{raw} format, but sets up
+metadata also.

 
 @item lazy_refcounts
 If this option is set to @code{on}, reference count updates are postponed with
 
 @item lazy_refcounts
 If this option is set to @code{on}, reference count updates are postponed with