mirror of https://gitee.com/openkylin/qemu.git
qemu-img: add support for fully allocated images
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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c3d8688470
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10
qemu-img.c
10
qemu-img.c
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@ -100,8 +100,12 @@ static void help(void)
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" '-h' with or without a command shows this help and lists the supported formats\n"
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" '-p' show progress of command (only certain commands)\n"
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" '-q' use Quiet mode - do not print any output (except errors)\n"
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" '-S' indicates the consecutive number of bytes that must contain only zeros\n"
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" for qemu-img to create a sparse image during conversion\n"
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" '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n"
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" contain only zeros for qemu-img to create a sparse image during\n"
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" conversion. If the number of bytes is 0, the source will not be scanned for\n"
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" unallocated or zero sectors, and the destination image will always be\n"
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" fully allocated\n"
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" images will always be fully allocated\n"
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" '--output' takes the format in which the output must be done (human or json)\n"
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" '-n' skips the target volume creation (useful if the volume is created\n"
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" prior to running qemu-img)\n"
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@ -1465,7 +1469,7 @@ static int img_convert(int argc, char **argv)
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/* signal EOF to align */
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bdrv_write_compressed(out_bs, 0, NULL, 0);
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} else {
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int has_zero_init = bdrv_has_zero_init(out_bs);
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int has_zero_init = min_sparse ? bdrv_has_zero_init(out_bs) : 0;
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sector_num = 0; // total number of sectors converted so far
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nb_sectors = total_sectors - sector_num;
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@ -193,6 +193,12 @@ Image conversion is also useful to get smaller image when using a
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growable format such as @code{qcow} or @code{cow}: the empty sectors
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are detected and suppressed from the destination image.
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@var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
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that must contain only zeros for qemu-img to create a sparse image during
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conversion. If @var{sparse_size} is 0, the source will not be scanned for
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unallocated or zero sectors, and the destination image will always be
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fully allocated.
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You can use the @var{backing_file} option to force the output image to be
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created as a copy on write image of the specified base image; the
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@var{backing_file} should have the same content as the input's base image,
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