Commit b2e10493 authored by Alexandre Derumier's avatar Alexandre Derumier Committed by Stefan Hajnoczi
Browse files

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: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarAlexandre Derumier <aderumier@odiso.com>
Signed-off-by: default avatarAlex Bligh <alex@alex.org.uk>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent b3f3a30f

qemu-img-cmds.hx

+2 −2
Original line number Diff line number Diff line
@@ -34,9 +34,9 @@ STEXI 
ETEXI



DEF("convert", img_convert,

    "convert [-c] [-p] [-q] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s snapshot_name] [-S sparse_size] filename [filename2 [...]] output_filename")

    "convert [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s snapshot_name] [-S sparse_size] filename [filename2 [...]] output_filename")

STEXI

@item convert [-c] [-p] [-q] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}

@item convert [-c] [-p] [-q] [-n] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}

ETEXI



DEF("info", img_info,

qemu-img.c

+38 −15
Original line number Diff line number Diff line
@@ -103,6 +103,8 @@ static void help(void) 
           "  '-S' indicates the consecutive number of bytes that must contain only zeros\n"

           "       for qemu-img to create a sparse image during conversion\n"

           "  '--output' takes the format in which the output must be done (human or json)\n"

           "  '-n' skips the target volume creation (useful if the volume is created\n"

           "       prior to running qemu-img)\n"

           "\n"

           "Parameters to check subcommand:\n"

           "  '-r' tries to repair any inconsistencies that are found during the check.\n"
@@ -1116,7 +1118,8 @@ out3: 


static int img_convert(int argc, char **argv)

{

    int c, ret = 0, n, n1, bs_n, bs_i, compress, cluster_size, cluster_sectors;

    int c, ret = 0, n, n1, bs_n, bs_i, compress, cluster_size,

        cluster_sectors, skip_create;

    int progress = 0, flags;

    const char *fmt, *out_fmt, *cache, *out_baseimg, *out_filename;

    BlockDriver *drv, *proto_drv;
@@ -1139,8 +1142,9 @@ static int img_convert(int argc, char **argv) 
    cache = "unsafe";

    out_baseimg = NULL;

    compress = 0;

    skip_create = 0;

    for(;;) {

        c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:q");

        c = getopt(argc, argv, "f:O:B:s:hce6o:pS:t:qn");

        if (c == -1) {

            break;

        }
@@ -1197,6 +1201,9 @@ static int img_convert(int argc, char **argv) 
        case 'q':

            quiet = true;

            break;

        case 'n':

            skip_create = 1;

            break;

        }

    }
@@ -1329,6 +1336,7 @@ static int img_convert(int argc, char **argv) 
        }

    }



    if (!skip_create) {

        /* Create the new image */

        ret = bdrv_create(drv, out_filename, param);

        if (ret < 0) {
@@ -1344,6 +1352,7 @@ static int img_convert(int argc, char **argv) 
            }

            goto out;

        }

    }



    flags = BDRV_O_RDWR;

    ret = bdrv_parse_cache_flags(cache, &flags);
@@ -1363,6 +1372,20 @@ static int img_convert(int argc, char **argv) 
    bdrv_get_geometry(bs[0], &bs_sectors);

    buf = qemu_blockalign(out_bs, IO_BUF_SIZE);



    if (skip_create) {

        int64_t output_length = bdrv_getlength(out_bs);

        if (output_length < 0) {

            error_report("unable to get output image length: %s\n",

                         strerror(-output_length));

            ret = -1;

            goto out;

        } else if (output_length < total_sectors << BDRV_SECTOR_BITS) {

            error_report("output file is smaller than input file");

            ret = -1;

            goto out;

        }

    }



    if (compress) {

        ret = bdrv_get_info(out_bs, &bdi);

        if (ret < 0) {

qemu-img.texi

+14 −1
Original line number Diff line number Diff line
@@ -96,6 +96,14 @@ Second image format 
Strict mode - fail on on different image size or sector allocation

@end table



Parameters to convert subcommand:



@table @option



@item -n

Skip the creation of the target volume

@end table



Command description:



@table @option
@@ -171,7 +179,7 @@ Error on reading data 


@end table



@item convert [-c] [-p] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}

@item convert [-c] [-p] [-n] [-f @var{fmt}] [-t @var{cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}



Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}

using format @var{output_fmt}. It can be optionally compressed (@code{-c}
@@ -190,6 +198,11 @@ 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 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

be supplied through qemu-img.



@item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}



Give information about the disk image @var{filename}. Use it in

tests/qemu-iotests/063

0 → 100755
+97 −0
Original line number Diff line number Diff line 
#!/bin/bash

#

# test of qemu-img convert -n - convert without creation

#

# Copyright (C) 2009 Red Hat, Inc.

# Copyright (C) 2013 Alex Bligh (alex@alex.org.uk)

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#



# creator

owner=alex@alex.org.uk



seq=`basename $0`

echo "QA output created by $seq"



here=`pwd`

tmp=/tmp/$$

status=1	# failure is the default!



_cleanup()

{

	_cleanup_test_img

	rm -f $TEST_IMG.orig $TEST_IMG.raw $TEST_IMG.raw2

}

trap "_cleanup; exit \$status" 0 1 2 3 15



# get standard environment, filters and checks

. ./common.rc

. ./common.filter

. ./common.pattern



_supported_fmt qcow qcow2 vmdk qed raw

_supported_proto generic

_supported_os Linux



_make_test_img 4M



echo "== Testing conversion with -n fails with no target file =="

# check .orig file does not exist

rm -f $TEST_IMG.orig

if $QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n $TEST_IMG $TEST_IMG.orig >/dev/null 2>&1; then

    exit 1

fi



echo "== Testing conversion with -n succeeds with a target file =="

rm -f $TEST_IMG.orig

cp $TEST_IMG $TEST_IMG.orig

if ! $QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n $TEST_IMG $TEST_IMG.orig ; then

    exit 1

fi



echo "== Testing conversion to raw is the same after conversion with -n =="

# compare the raw files

if ! $QEMU_IMG convert -f $IMGFMT -O raw $TEST_IMG $TEST_IMG.raw1 ; then

    exit 1

fi



if ! $QEMU_IMG convert -f $IMGFMT -O raw $TEST_IMG.orig $TEST_IMG.raw2 ; then

    exit 1

fi



if ! cmp $TEST_IMG.raw1 $TEST_IMG.raw2 ; then

    exit 1

fi



echo "== Testing conversion back to original format =="

if ! $QEMU_IMG convert -f raw -O $IMGFMT -n $TEST_IMG.raw2 $TEST_IMG ; then

    exit 1

fi

_check_test_img



echo "== Testing conversion to a smaller file fails =="

rm -f $TEST_IMG.orig

mv $TEST_IMG $TEST_IMG.orig

_make_test_img 2M

if $QEMU_IMG convert -f $IMGFMT -O $IMGFMT -n $TEST_IMG.orig $TEST_IMG >/dev/null 2>&1; then

    exit 1

fi



rm -f $TEST_IMG.orig $TEST_IMG.raw $TEST_IMG.raw2



echo "*** done"

rm -f $seq.full

status=0

exit 0

tests/qemu-iotests/063.out

0 → 100644
+10 −0
Original line number Diff line number Diff line 
QA output created by 063

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304

== Testing conversion with -n fails with no target file ==

== Testing conversion with -n succeeds with a target file ==

== Testing conversion to raw is the same after conversion with -n ==

== Testing conversion back to original format ==

No errors were found on the image.

== Testing conversion to a smaller file fails ==

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2097152

*** done