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>
This commit is contained in:
Reda Sallahi
Max Reitz
parent
86ce1f6e2b
commit
f7c1553388
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@ -46,9 +46,9 @@ STEXI
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ETEXI
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DEF("dd", img_dd,
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"dd [--image-opts] [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks] if=input of=output")
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"dd [--image-opts] [-f fmt] [-O output_fmt] [bs=block_size] [count=blocks] [skip=blocks] if=input of=output")
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STEXI
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@item dd [--image-opts] [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] if=@var{input} of=@var{output}
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@item dd [--image-opts] [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output}
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ETEXI
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DEF("info", img_info,
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50
qemu-img.c
50
qemu-img.c
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@ -173,7 +173,8 @@ static void QEMU_NORETURN help(void)
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"(default: 512)\n"
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" 'count=N' copy only N input blocks\n"
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" 'if=FILE' read from FILE\n"
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" 'of=FILE' write to FILE\n";
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" 'of=FILE' write to FILE\n"
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" 'skip=N' skip N bs-sized blocks at the start of input\n";
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printf("%s\nSupported formats:", help_msg);
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bdrv_iterate_format(format_print, NULL);
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@ -3807,6 +3808,7 @@ out:
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#define C_COUNT 02
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#define C_IF 04
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#define C_OF 010
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#define C_SKIP 020
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struct DdInfo {
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unsigned int flags;
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@ -3817,6 +3819,7 @@ struct DdIo {
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int bsz; /* Block size */
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char *filename;
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uint8_t *buf;
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int64_t offset;
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};
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struct DdOpts {
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@ -3877,6 +3880,22 @@ static int img_dd_of(const char *arg,
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return 0;
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}
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static int img_dd_skip(const char *arg,
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struct DdIo *in, struct DdIo *out,
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struct DdInfo *dd)
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{
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char *end;
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in->offset = qemu_strtosz_suffix(arg, &end, QEMU_STRTOSZ_DEFSUFFIX_B);
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if (in->offset < 0 || *end) {
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error_report("invalid number: '%s'", arg);
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return 1;
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}
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return 0;
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}
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static int img_dd(int argc, char **argv)
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{
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int ret = 0;
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@ -3900,12 +3919,14 @@ static int img_dd(int argc, char **argv)
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struct DdIo in = {
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.bsz = 512, /* Block size is by default 512 bytes */
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.filename = NULL,
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.buf = NULL
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.buf = NULL,
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.offset = 0
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};
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struct DdIo out = {
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.bsz = 512,
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.filename = NULL,
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.buf = NULL
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.buf = NULL,
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.offset = 0
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};
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const struct DdOpts options[] = {
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@ -3913,6 +3934,7 @@ static int img_dd(int argc, char **argv)
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{ "count", img_dd_count, C_COUNT },
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{ "if", img_dd_if, C_IF },
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{ "of", img_dd_of, C_OF },
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{ "skip", img_dd_skip, C_SKIP },
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{ NULL, NULL, 0 }
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};
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const struct option long_options[] = {
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@ -4032,7 +4054,14 @@ static int img_dd(int argc, char **argv)
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size = dd.count * in.bsz;
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}
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qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
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/* Overflow means the specified offset is beyond input image's size */
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if (dd.flags & C_SKIP && (in.offset > INT64_MAX / in.bsz ||
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size < in.bsz * in.offset)) {
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qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 0, &error_abort);
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} else {
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qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
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size - in.bsz * in.offset, &error_abort);
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}
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ret = bdrv_create(drv, out.filename, opts, &local_err);
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if (ret < 0) {
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@ -4051,9 +4080,20 @@ static int img_dd(int argc, char **argv)
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goto out;
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}
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if (dd.flags & C_SKIP && (in.offset > INT64_MAX / in.bsz ||
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size < in.offset * in.bsz)) {
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/* We give a warning if the skip option is bigger than the input
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* size and create an empty output disk image (i.e. like dd(1)).
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*/
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error_report("%s: cannot skip to specified offset", in.filename);
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in_pos = size;
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} else {
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in_pos = in.offset * in.bsz;
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}
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in.buf = g_new(uint8_t, in.bsz);
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for (in_pos = 0, out_pos = 0; in_pos < size; block_count++) {
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for (out_pos = 0; in_pos < size; block_count++) {
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int in_ret, out_ret;
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if (in_pos + in.bsz > size) {
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@ -151,6 +151,8 @@ sets the number of input blocks to copy
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sets the input file
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@item of=@var{output}
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sets the output file
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@item skip=@var{blocks}
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sets the number of input blocks to skip
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@end table
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Command description:
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@ -324,7 +326,7 @@ skipped. This is useful for formats such as @code{rbd} if the target
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volume has already been created with site specific options that cannot
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be supplied through qemu-img.
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@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] if=@var{input} of=@var{output}
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@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}
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Dd copies from @var{input} file to @var{output} file converting it from
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@var{fmt} format to @var{output_fmt} format.
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@ -0,0 +1,72 @@
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#! /bin/bash
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#
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# qemu-img dd test for the skip option
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#
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# Copyright (C) 2016 Reda Sallahi
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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#
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owner=fullmanet@gmail.com
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seq="$(basename $0)"
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echo "QA output created by $seq"
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here="$PWD"
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status=1
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_cleanup()
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{
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_cleanup_test_img
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rm -f "$TEST_IMG.out" "$TEST_IMG.out.dd"
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}
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trap "_cleanup; exit \$status" 0 1 2 3 15
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. ./common.rc
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. ./common.filter
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. ./common.pattern
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_supported_fmt raw
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_supported_proto file
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_supported_os Linux
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TEST_SKIP_BLOCKS="1 2 30 30K"
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for skip in $TEST_SKIP_BLOCKS; do
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echo
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echo "== Creating image =="
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size=1M
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_make_test_img $size
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_check_test_img
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$QEMU_IO -c "write -P 0xa 24 512k" "$TEST_IMG" | _filter_qemu_io
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echo
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echo "== Converting the image with dd with skip=$skip =="
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$QEMU_IMG dd if="$TEST_IMG" of="$TEST_IMG.out" skip="$skip" -O "$IMGFMT" \
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2> /dev/null
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TEST_IMG="$TEST_IMG.out" _check_test_img
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dd if="$TEST_IMG" of="$TEST_IMG.out.dd" skip="$skip" status=none
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echo
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echo "== Compare the images with qemu-img compare =="
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$QEMU_IMG compare "$TEST_IMG.out.dd" "$TEST_IMG.out"
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done
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echo
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echo "*** done"
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rm -f "$seq.full"
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status=0
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@ -0,0 +1,51 @@
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QA output created by 160
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== Creating image ==
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
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No errors were found on the image.
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wrote 524288/524288 bytes at offset 24
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512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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== Converting the image with dd with skip=1 ==
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No errors were found on the image.
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== Compare the images with qemu-img compare ==
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Images are identical.
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== Creating image ==
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
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No errors were found on the image.
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wrote 524288/524288 bytes at offset 24
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512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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== Converting the image with dd with skip=2 ==
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No errors were found on the image.
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== Compare the images with qemu-img compare ==
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Images are identical.
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== Creating image ==
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
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No errors were found on the image.
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wrote 524288/524288 bytes at offset 24
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512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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== Converting the image with dd with skip=30 ==
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No errors were found on the image.
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== Compare the images with qemu-img compare ==
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Images are identical.
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== Creating image ==
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
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No errors were found on the image.
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wrote 524288/524288 bytes at offset 24
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512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
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== Converting the image with dd with skip=30K ==
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No errors were found on the image.
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== Compare the images with qemu-img compare ==
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Images are identical.
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*** done
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@ -158,5 +158,6 @@
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156 rw auto quick
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157 auto
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159 rw auto quick
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160 rw auto quick
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162 auto quick
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170 rw auto quick
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