Commit Graph

48 Commits

Author SHA1 Message Date
Pavel Butsykin 4ffca8904a qemu-img: add --shrink flag for resize
The flag is additional precaution against data loss. Perhaps in the future the
operation shrink without this flag will be blocked for all formats, but for now
we need to maintain compatibility with raw.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170918124230.8152-2-pbutsykin@virtuozzo.com
[mreitz: Added a missing space to a warning]
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-09-26 15:00:32 +02:00
Eric Blake 57b2d9d4a7 qemu-img: Sort sub-command names in --help
'amend' and 'create' were not listed alphabetically; hoist them
earlier.  Separate the @end table block to make it easier to
copy-and-paste the addition of future sub-commands.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20170803163353.19558-2-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-08 17:28:53 +02:00
John Snow 6e6e55f5c2 qemu-img: Check for backing image if specified during create
Or, rather, force the open of a backing image if one was specified
for creation. Using a similar -unsafe option as rebase, allow qemu-img
to ignore the backing file validation if possible.

It may not always be possible, as in the existing case when a filesize
for the new image was not specified.

This is accomplished by shifting around the conditionals in
bdrv_img_create, such that a backing file is always opened unless we
provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
when -u is provided to create.

Sorry for the heinous looking diffstat, but it's mostly whitespace.

Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-07-18 15:27:37 +02:00
Stefan Hajnoczi fd03c2b8fb qemu-img: add measure subcommand
The measure subcommand calculates the size required by a new image file.
This can be used by users or management tools that need to allocate
space on an LVM volume, SAN LUN, etc before creating or converting an
image file.

Suggested-by: Maor Lipchuk <mlipchuk@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20170705125738.8777-8-stefanha@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11 17:45:01 +02:00
Daniel P. Berrange 305b4c60f2 qemu-img: introduce --target-image-opts for 'convert' command
The '--image-opts' flag indicates whether the source filename
includes options. The target filename has to remain in the
plain filename format though, since it needs to be passed to
bdrv_create().  When using --skip-create though, it would be
possible to use image-opts syntax. This adds --target-image-opts
to indicate that the target filename includes options. Currently
this mandates use of the --skip-create flag too.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170515164712.6643-4-berrange@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-29 15:39:54 +02:00
Fam Zheng caa31bf28c qemu-img: Fix documentation of convert
It got lost in commit a8d16f9ca "qemu-img: Update documentation for -U".

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-id: 20170515103551.31313-1-famz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-29 15:39:53 +02:00
Fam Zheng a8d16f9ca2 qemu-img: Update documentation for -U
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-11 11:08:40 +02:00
Max Reitz 2b4c0a20fb qemu-img: Document backing options
The create and convert subcommands have shorthands to set the
backing_file and, in the case of create, the backing_fmt options for the
new image. However, they have not been documented so far, which is
remedied by this patch.

Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-04-27 17:26:31 +02:00
Jeff Cody 89aa0465b9 qemu-img: img_create does not support image-opts, fix docs
The documentation and help for qemu-img claims that 'qemu-img create'
will take the '--image-opts' argument.  This is not true, so this
patch removes those claims.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-04-07 14:44:06 +02:00
Peter Lieven 2d9187bc65 qemu-img: make convert async
the convert process is currently completely implemented with sync operations.
That means it reads one buffer and then writes it. No parallelism and each sync
request takes as long as it takes until it is completed.

This can be a big performance hit when the convert process reads and writes
to devices which do not benefit from kernel readahead or pagecache.
In our environment we heavily have the following two use cases when using
qemu-img convert.

a) reading from NFS and writing to iSCSI for deploying templates
b) reading from iSCSI and writing to NFS for backups

In both processes we use libiscsi and libnfs so we have no kernel cache.

This patch changes the convert process to work with parallel running coroutines
which can significantly improve performance for network storage devices:

qemu-img (master)
 nfs -> iscsi 22.8 secs
 nfs -> ram   11.7 secs
 ram -> iscsi 12.3 secs

qemu-img-async (8 coroutines, in-order write disabled)
 nfs -> iscsi 11.0 secs
 nfs -> ram   10.4 secs
 ram -> iscsi  9.0 secs

This patches introduces 2 new cmdline parameters. The -m parameter to specify
the number of coroutines running in parallel (defaults to 8). And the -W parameter to
allow qemu-img to write to the target out of order rather than sequential. This improves
performance as the writes do not have to wait for each other to complete.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-02-28 20:40:31 +01:00
Reda Sallahi f7c1553388 qemu-img: add skip option to dd
This adds the skip option which allows qemu-img dd to skip a number of blocks
before copying the input.

A test case was added to test the skip option.

Signed-off-by: Reda Sallahi <fullmanet@gmail.com>
Message-id: 20160810141609.32727-1-fullmanet@gmail.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-09-20 22:10:57 +02:00
Reda Sallahi 86ce1f6e2b qemu-img: add the 'dd' subcommand
This patch adds a basic dd subcommand analogous to dd(1) to qemu-img.

For the start, this implements the bs, if, of and count options and requires
both if and of to be specified (no stdin/stdout if not specified) and doesn't
support tty, pipes, etc.

The image format must be specified with -O for the output if the raw format
is not the intended one.

Two tests are added to test qemu-img dd.

Signed-off-by: Reda Sallahi <fullmanet@gmail.com>
Message-id: 20160810024312.14544-1-fullmanet@gmail.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[mreitz: Moved test 158 to 170]
Signed-off-by: Max Reitz <mreitz@redhat.com>
2016-09-20 22:10:57 +02:00
Kevin Wolf 55d539c8f7 qemu-img bench: Add --flush-interval
This options allows to flush the image periodically during write tests.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-08 10:21:09 +02:00
Kevin Wolf 83de9be0dc qemu-img bench: Implement -S (step size)
With this new option, qemu-img bench can be told to advance the current
offset after each request by a different value than the buffer size.
This is useful for controlling the conditions for cluster allocation in
image formats (e.g. qcow2 cluster allocation with COW in front of the
request, or COW areas that aren't overwritten immediately).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-08 10:21:09 +02:00
Kevin Wolf d3199a31c7 qemu-img bench: Make start offset configurable
This patch adds an option the specify the offset of the first request
made by qemu-img bench. This allows to benchmark misaligned requests.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-08 10:21:09 +02:00
Kevin Wolf b6495fa849 qemu-img bench: Sequential writes
This extends qemu-img bench with an option that makes it use sequential
writes instead of reads for the test run.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-08 10:21:09 +02:00
Kevin Wolf b6133b8c68 qemu-img bench
This adds a qemu-img command that allows doing some simple benchmarks
for the block layer without involving guest devices and a real VM.

For the start, this implements only a test of sequential reads.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-08 10:21:09 +02:00
Daniel P. Berrange eb769f7420 qemu-img: allow specifying image as a set of options args
Currently qemu-img allows an image filename to be passed on the
command line, but unless using the JSON format, it does not have
a way to set any options except the format eg

   qemu-img info https://127.0.0.1/images/centos7.iso

This adds a --image-opts arg that indicates that the positional
filename should be interpreted as a full option string, not
just a filename.

   qemu-img info --image-opts driver=https,url=https://127.0.0.1/images,sslverify=off

This flag is mutually exclusive with the '-f' / '-F' flags.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-02-22 09:50:04 +01:00
Daniel P. Berrange 3babeb153c qemu-img: add support for --object command line arg
Allow creation of user creatable object types with qemu-img
via a new --object command line arg. This will be used to supply
passwords and/or encryption keys to the various block driver
backends via the recently added 'secret' object type.

 # printf letmein > mypasswd.txt
 # qemu-img info --object secret,id=sec0,file=mypasswd.txt \
      ...other info args...

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-02-22 09:50:04 +01:00
Max Reitz 76a3a34dce qemu-img: Add progress output for amend
Now that bdrv_amend_options() supports a status callback, use it to
display a progress report.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414404776-4919-3-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 11:41:48 +00:00
Max Reitz 1b22bffd82 qemu-img: Specify backing file for commit
Introduce a new parameter for qemu-img commit which may be used to
explicitly specify the backing file into which an image should be
committed if the backing chain has more than a single layer.

[Applied Eric Blake's qemu-img.texi documentation rewording
--Stefan]

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1414159063-25977-12-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 11:41:48 +00:00
Max Reitz 687fa1d830 qemu-img: Enable progress output for commit
Implement progress output for the commit command by querying the
progress of the block job.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414159063-25977-11-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 11:41:48 +00:00
Max Reitz 9a86fe4895 qemu-img: Empty image after commit
After the top image has been committed, it should be emptied unless
specified otherwise.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1414159063-25977-10-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-03 11:41:48 +00:00
Max Reitz bd39e6ed0b qemu-img: Allow cache mode specification for amend
qemu-img amend may extensively modify the target image, depending on the
options to be amended (e.g. conversion to qcow2 compat level 0.10 from
1.1 for an image with many unallocated zero clusters). Therefore it
makes sense to allow the user to specify the cache mode to be used.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-22 14:54:48 +02:00
Max Reitz 40055951a7 qemu-img: Allow source cache mode specification
Many qemu-img subcommands only read the source file(s) once. For these
use cases, a full write-back cache is unnecessary and mainly clutters
host cache memory. Though this is generally no concern as cache memory
is freely available and can be scaled by the host OS, it may become a
concern with thin provisioning.

For these cases, it makes sense to allow users to freely specify the
source cache mode (e.g. use no cache at all).

This commit adds a new switch (-T) for the qemu-img subcommands check,
compare, convert and rebase to specify the cache to be used for source
images (the backing file in case of rebase).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-22 14:54:44 +02:00
Wenchao Xia ef80654d0d qemu-img: add -l for snapshot in convert
Now qemu-img convert have similar options as qemu-nbd for internal
snapshot.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04 15:19:00 +01:00
Max Reitz 6f176b48f9 block: Image file option amendment
This patch adds the "amend" option to qemu-img which allows changing
image options on existing image files. It also adds the generic bdrv
implementation which is basically just a wrapper for the image format
specific function.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-09-12 10:12:46 +02:00
Paolo Bonzini 4c93a13b5d qemu-img: add a "map" subcommand
This command dumps the metadata of an entire chain, in either tabular or JSON
format.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06 15:25:09 +02:00
Alexandre Derumier b2e10493c7 add qemu-img convert -n option (skip target volume creation)
Add a -n option to skip volume creation on qemu-img convert.
This is useful for targets such as rbd / ceph, where the
target volume may already exist; we cannot always rely on
qemu-img convert to create the image, as dependent on the
output format, there may be parameters which are not possible
to specify through the qemu-img convert command line.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-09-06 15:25:07 +02:00
Miroslav Rezanina d14ed18c8d qemu-img: Add compare subcommand
This patch adds new qemu-img subcommand that compares content of two disk
images.

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22 21:21:10 +01:00
Miroslav Rezanina f382d43a91 qemu-img: Add "Quiet mode" option
There can be a need to turn output to stdout off. This patch adds a -q option
that enable "Quiet mode". In Quiet mode, only errors are printed out.

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-02-22 21:21:09 +01:00
Federico Simoncelli 8599ea4c42 qemu-img: add json output option to the check command
This option --output=[human|json] makes qemu-img check output a human
or JSON representation at the choice of the user.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-02-22 21:21:08 +01:00
Kashyap Chamarthy e53575606a qemu-img: document 'info --backing-chain'
Signed-off-by: Kashyap Chamarthy <kashyap.cv@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-10-24 10:26:19 +02:00
Benoît Canet c054b3fd78 qemu-img: Add json output option to the info command.
This option --output=[human|json] make qemu-img info output on
human or JSON representation at the choice of the user.

example:
{
    "snapshots": [
        {
            "vm-clock-nsec": 637102488,
            "name": "vm-20120821145509",
            "date-sec": 1345553709,
            "date-nsec": 220289000,
            "vm-clock-sec": 20,
            "id": "1",
            "vm-state-size": 96522745
        },
        {
            "vm-clock-nsec": 28210866,
            "name": "vm-20120821154059",
            "date-sec": 1345556459,
            "date-nsec": 171392000,
            "vm-clock-sec": 46,
            "id": "2",
            "vm-state-size": 101208714
        }
    ],
    "virtual-size": 1073741824,
    "filename": "snap.qcow2",
    "cluster-size": 65536,
    "format": "qcow2",
    "actual-size": 985587712,
    "dirty-flag": false
}

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-09-12 15:50:09 +02:00
Kevin Wolf 4534ff5426 qemu-img check -r for repairing images
The QED block driver already provides the functionality to not only
detect inconsistencies in images, but also fix them. However, this
functionality cannot be manually invoked with qemu-img, but the
check happens only automatically during bdrv_open().

This adds a -r switch to qemu-img check that allows manual invocation
of an image repair.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-06-15 14:03:42 +02:00
Kevin Wolf 3763f26f2f Documentation: Add qemu-img -t parameter in man page
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-12-15 12:40:08 +01:00
Kevin Wolf a22f123ca3 qemu-img: Require larger zero areas for sparse handling
By default, require 4k of consecutive zero bytes for qemu-img to make the
output file sparse by not issuing a write request for the zeroed parts. Add an
-S option to allow users to tune this setting.

This helps to avoid situations where a lot of zero sectors and data sectors are
mixed and qemu-img tended to issue many tiny 512 byte writes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-08-29 14:42:39 +02:00
Jes Sorensen aaf55b4795 Add missing documentation for qemu-img -p
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-07-20 11:13:52 +02:00
Federico Simoncelli 661a0f712b qemu-img: Add cache command line option
qemu-img currently writes disk images using writeback and filling
up the cache buffers which are then flushed by the kernel preventing
other processes from accessing the storage.
This is particularly bad in cluster environments where time-based
algorithms might be in place and accessing the storage within
certain timeouts is critical.
This patch adds the option to choose a cache method when writing
disk images.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-07-05 11:23:29 +02:00
Jes Sorensen 6b837bc4a4 qemu-img: Initial progress printing support
This adds the basic infrastructure for supporting progress output
on the command line, as well as progress support for qemu-img commands
'rebase' and 'convert'.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-04-07 13:51:47 +02:00
edison 51ef67270b Copy snapshots out of QCOW2 disk
In order to backup snapshots, created from QCOW2 iamge, we want to copy snapshots out of QCOW2 disk to a seperate storage.
The following patch adds a new option in "qemu-img": qemu-img convert -f qcow2 -O qcow2 -s snapshot_name src_img bck_img.
Right now, it only supports to copy the full snapshot, delta snapshot is on the way.

Changes from V1: all the comments from Kevin are addressed:
Add read-only checking
Fix coding style
Change the name from bdrv_snapshot_load to bdrv_snapshot_load_tmp

Signed-off-by: Disheng Su <edison@cloud.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-10-22 14:49:35 +02:00
Stefan Weil 5fb58b067a qemu-img: Fix copy+paste bug in documentation
Replace rebase by resize in documentation of resize command.

Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Kevin Wolf <kwolf@redhat.com>

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-07-13 17:48:17 +02:00
Jan Kiszka 3c4c32101b Fix TEXI section mark imbalance in qemu-img-cmd.hx
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2010-05-22 08:33:50 +00:00
Stefan Hajnoczi ae6b0ed6d4 qemu-img: Add 'resize' command to grow/shrink disk images
This patch adds a 'resize' command to grow/shrink disk images.  This
allows changing the size of disk images without copying to a new image
file.  Currently only raw files support resize.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03 10:07:32 +02:00
Kevin Wolf cb66ffcf9e qemu-img rebase: Document -f option
The option was implemented in e53dbee0, but I forgot documenting it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
2010-03-14 23:56:47 +01:00
Kevin Wolf 3e85c6fd71 qemu-img rebase
This adds a rebase subcommand to qemu-img which allows to change the backing
file of an image.

In default mode, both the current and the new backing file need to exist, and
after the rebase, the COW image is guaranteed to have the same guest visible
content as before. To achieve this, old and new backing file are compared and,
if necessary, data is copied from the old backing file into the COW image.

With -u an unsafe mode is enabled that doesn't require the backing files to
exist. It merely changes the backing file reference in the COW image. This is
useful for renaming or moving the backing file. The user is responsible to make
sure that the new backing file has no changes compared to the old one, or
corruption may occur.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-13 17:14:15 -06:00
Kevin Wolf 8063d0fe3b Documentation: Don't mention old qemu-img options
The old options are still supported for compatibility, but they are
inconsistent (for example create -b vs. convert -B for backing files) and
incomplete (-F only exists for create) which tends to confuse people. Remove
all references to the old options from the documentation to guide users to the
more consistent -o options.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-11-09 08:43:12 -06:00
Stuart Brady 153859be1a Use hxtool for qemu-img command list
Use hxtool to generate the 'command syntax' section of qemu-img's help
message, and the corresponding section of the texinfo documentation.

This has the side-effect of adding 'check' to this list of commands in
the texinfo documentation.

Signed-off-by: Stuart Brady <stuart.brady@gmail.com>
2009-06-07 09:59:47 +03:00