New qemu-img convert -B option, by Marc Bevand.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4672 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
parent
ff7ab59f40
commit
f58c7b3545
27
block.c
27
block.c
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@ -884,6 +884,33 @@ void bdrv_flush(BlockDriverState *bs)
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bdrv_flush(bs->backing_hd);
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bdrv_flush(bs->backing_hd);
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}
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}
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/*
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* Returns true iff the specified sector is present in the disk image. Drivers
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* not implementing the functionality are assumed to not support backing files,
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* hence all their sectors are reported as allocated.
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*
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* 'pnum' is set to the number of sectors (including and immediately following
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* the specified sector) that are known to be in the same
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* allocated/unallocated state.
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*
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* 'nb_sectors' is the max value 'pnum' should be set to.
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*/
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int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
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int *pnum)
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{
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int64_t n;
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if (!bs->drv->bdrv_is_allocated) {
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if (sector_num >= bs->total_sectors) {
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*pnum = 0;
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return 0;
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}
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n = bs->total_sectors - sector_num;
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*pnum = (n < nb_sectors) ? (n) : (nb_sectors);
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return 1;
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}
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return bs->drv->bdrv_is_allocated(bs, sector_num, nb_sectors, pnum);
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}
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#ifndef QEMU_IMG
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#ifndef QEMU_IMG
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void bdrv_info(void)
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void bdrv_info(void)
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{
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{
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2
block.h
2
block.h
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@ -99,6 +99,8 @@ int qemu_key_check(BlockDriverState *bs, const char *name);
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/* Ensure contents are flushed to disk. */
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/* Ensure contents are flushed to disk. */
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void bdrv_flush(BlockDriverState *bs);
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void bdrv_flush(BlockDriverState *bs);
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int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
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int *pnum);
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#define BDRV_TYPE_HD 0
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#define BDRV_TYPE_HD 0
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#define BDRV_TYPE_CDROM 1
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#define BDRV_TYPE_CDROM 1
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47
qemu-img.c
47
qemu-img.c
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@ -55,13 +55,17 @@ static void help(void)
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"Command syntax:\n"
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"Command syntax:\n"
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" create [-e] [-6] [-b base_image] [-f fmt] filename [size]\n"
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" create [-e] [-6] [-b base_image] [-f fmt] filename [size]\n"
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" commit [-f fmt] filename\n"
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" commit [-f fmt] filename\n"
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" convert [-c] [-e] [-6] [-f fmt] [-O output_fmt] filename [filename2 [...]] output_filename\n"
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" convert [-c] [-e] [-6] [-f fmt] [-O output_fmt] [-B output_base_image] filename [filename2 [...]] output_filename\n"
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" info [-f fmt] filename\n"
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" info [-f fmt] filename\n"
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"\n"
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"\n"
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"Command parameters:\n"
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"Command parameters:\n"
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" 'filename' is a disk image filename\n"
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" 'filename' is a disk image filename\n"
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" 'base_image' is the read-only disk image which is used as base for a copy on\n"
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" 'base_image' is the read-only disk image which is used as base for a copy on\n"
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" write image; the copy on write image only stores the modified data\n"
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" write image; the copy on write image only stores the modified data\n"
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" 'output_base_image' forces the output image to be created as a copy on write\n"
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" image of the specified base image; 'output_base_image' should have the same\n"
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" content as the input's base image, however the path, image format, etc may\n"
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" differ\n"
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" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
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" 'fmt' is the disk image format. It is guessed automatically in most cases\n"
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" 'size' is the disk image size in kilobytes. Optional suffixes 'M' (megabyte)\n"
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" 'size' is the disk image size in kilobytes. Optional suffixes 'M' (megabyte)\n"
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" and 'G' (gigabyte) are supported\n"
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" and 'G' (gigabyte) are supported\n"
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@ -350,6 +354,13 @@ static int is_not_zero(const uint8_t *sector, int len)
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return 0;
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return 0;
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}
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}
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/*
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* Returns true iff the first sector pointed to by 'buf' contains at least
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* a non-NUL byte.
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*
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* 'pnum' is set to the number of sectors (including and immediately following
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* the first one) that are known to be in the same allocated/unallocated state.
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*/
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static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
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static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
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{
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{
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int v, i;
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int v, i;
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@ -373,7 +384,7 @@ static int is_allocated_sectors(const uint8_t *buf, int n, int *pnum)
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static int img_convert(int argc, char **argv)
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static int img_convert(int argc, char **argv)
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{
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{
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int c, ret, n, n1, bs_n, bs_i, flags, cluster_size, cluster_sectors;
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int c, ret, n, n1, bs_n, bs_i, flags, cluster_size, cluster_sectors;
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const char *fmt, *out_fmt, *out_filename;
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const char *fmt, *out_fmt, *out_baseimg, *out_filename;
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BlockDriver *drv;
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BlockDriver *drv;
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BlockDriverState **bs, *out_bs;
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BlockDriverState **bs, *out_bs;
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int64_t total_sectors, nb_sectors, sector_num, bs_offset;
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int64_t total_sectors, nb_sectors, sector_num, bs_offset;
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@ -384,9 +395,10 @@ static int img_convert(int argc, char **argv)
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fmt = NULL;
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fmt = NULL;
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out_fmt = "raw";
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out_fmt = "raw";
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out_baseimg = NULL;
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flags = 0;
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flags = 0;
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for(;;) {
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for(;;) {
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c = getopt(argc, argv, "f:O:hce6");
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c = getopt(argc, argv, "f:O:B:hce6");
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if (c == -1)
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if (c == -1)
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break;
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break;
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switch(c) {
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switch(c) {
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@ -399,6 +411,9 @@ static int img_convert(int argc, char **argv)
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case 'O':
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case 'O':
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out_fmt = optarg;
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out_fmt = optarg;
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break;
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break;
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case 'B':
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out_baseimg = optarg;
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break;
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case 'c':
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case 'c':
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flags |= BLOCK_FLAG_COMPRESS;
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flags |= BLOCK_FLAG_COMPRESS;
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break;
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break;
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@ -416,6 +431,9 @@ static int img_convert(int argc, char **argv)
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out_filename = argv[argc - 1];
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out_filename = argv[argc - 1];
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if (bs_n > 1 && out_baseimg)
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error("-B makes no sense when concatenating multiple input images");
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bs = calloc(bs_n, sizeof(BlockDriverState *));
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bs = calloc(bs_n, sizeof(BlockDriverState *));
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if (!bs)
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if (!bs)
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error("Out of memory");
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error("Out of memory");
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@ -441,7 +459,7 @@ static int img_convert(int argc, char **argv)
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if (flags & BLOCK_FLAG_ENCRYPT && flags & BLOCK_FLAG_COMPRESS)
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if (flags & BLOCK_FLAG_ENCRYPT && flags & BLOCK_FLAG_COMPRESS)
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error("Compression and encryption not supported at the same time");
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error("Compression and encryption not supported at the same time");
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ret = bdrv_create(drv, out_filename, total_sectors, NULL, flags);
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ret = bdrv_create(drv, out_filename, total_sectors, out_baseimg, flags);
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if (ret < 0) {
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if (ret < 0) {
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if (ret == -ENOTSUP) {
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if (ret == -ENOTSUP) {
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error("Formatting not supported for file format '%s'", fmt);
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error("Formatting not supported for file format '%s'", fmt);
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@ -520,7 +538,7 @@ static int img_convert(int argc, char **argv)
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/* signal EOF to align */
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/* signal EOF to align */
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bdrv_write_compressed(out_bs, 0, NULL, 0);
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bdrv_write_compressed(out_bs, 0, NULL, 0);
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} else {
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} else {
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sector_num = 0;
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sector_num = 0; // total number of sectors converted so far
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for(;;) {
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for(;;) {
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nb_sectors = total_sectors - sector_num;
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nb_sectors = total_sectors - sector_num;
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if (nb_sectors <= 0)
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if (nb_sectors <= 0)
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@ -543,6 +561,20 @@ static int img_convert(int argc, char **argv)
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if (n > bs_offset + bs_sectors - sector_num)
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if (n > bs_offset + bs_sectors - sector_num)
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n = bs_offset + bs_sectors - sector_num;
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n = bs_offset + bs_sectors - sector_num;
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/* If the output image is being created as a copy on write image,
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assume that sectors which are unallocated in the input image
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are present in both the output's and input's base images (no
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need to copy them). */
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if (out_baseimg) {
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if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset, n, &n1)) {
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sector_num += n1;
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continue;
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}
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/* The next 'n1' sectors are allocated in the input image. Copy
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only those as they may be followed by unallocated sectors. */
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n = n1;
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}
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if (bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n) < 0)
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if (bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n) < 0)
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error("error while reading");
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error("error while reading");
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/* NOTE: at the same time we convert, we do not write zero
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/* NOTE: at the same time we convert, we do not write zero
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@ -550,7 +582,10 @@ static int img_convert(int argc, char **argv)
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should add a specific call to have the info to go faster */
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should add a specific call to have the info to go faster */
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buf1 = buf;
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buf1 = buf;
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while (n > 0) {
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while (n > 0) {
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if (is_allocated_sectors(buf1, n, &n1)) {
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/* If the output image is being created as a copy on write image,
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copy all sectors even the ones containing only NUL bytes,
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because they may differ from the sectors in the base image. */
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if (out_baseimg || is_allocated_sectors(buf1, n, &n1)) {
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if (bdrv_write(out_bs, sector_num, buf1, n1) < 0)
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if (bdrv_write(out_bs, sector_num, buf1, n1) < 0)
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error("error while writing");
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error("error while writing");
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}
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}
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@ -10,7 +10,7 @@ The following commands are supported:
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@table @option
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@table @option
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@item create [-e] [-6] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
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@item create [-e] [-6] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
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@item commit [-f @var{fmt}] @var{filename}
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@item commit [-f @var{fmt}] @var{filename}
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@item convert [-c] [-e] [-6] [-f @var{fmt}] [-O @var{output_fmt}] @var{filename} [@var{filename2} [...]] @var{output_filename}
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@item convert [-c] [-e] [-6] [-f @var{fmt}] [-O @var{output_fmt}] [-B @var{output_base_image}] @var{filename} [@var{filename2} [...]] @var{output_filename}
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@item info [-f @var{fmt}] @var{filename}
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@item info [-f @var{fmt}] @var{filename}
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@end table
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@end table
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@ -21,7 +21,11 @@ Command parameters:
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@item base_image
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@item base_image
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is the read-only disk image which is used as base for a copy on
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is the read-only disk image which is used as base for a copy on
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write image; the copy on write image only stores the modified data
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write image; the copy on write image only stores the modified data
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@item output_base_image
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forces the output image to be created as a copy on write
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image of the specified base image; @code{output_base_image} should have the same
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content as the input's base image, however the path, image format, etc may
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differ
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@item fmt
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@item fmt
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is the disk image format. It is guessed automatically in most cases. The following formats are supported:
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is the disk image format. It is guessed automatically in most cases. The following formats are supported:
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