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authorPeter Lieven <pl@kamp.de>2013-10-24 12:07:05 +0200
committerKevin Wolf <kwolf@redhat.com>2013-11-28 10:30:52 +0100
commit11b6699af59b8684128debacfc7c44cbaa6ac53b (patch)
tree631f7f7c1a398d2868fcb3cd3c719058a0173682
parentc3d8688470a33feb0ea78c006b4399d50c13185e (diff)
qemu-img: add support for fully allocated images
Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--qemu-img.c10
-rw-r--r--qemu-img.texi6
2 files changed, 13 insertions, 3 deletions
diff --git a/qemu-img.c b/qemu-img.c
index b6b5644cb6..cc3fed7b44 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -100,8 +100,12 @@ static void help(void)
" '-h' with or without a command shows this help and lists the supported formats\n"
" '-p' show progress of command (only certain commands)\n"
" '-q' use Quiet mode - do not print any output (except errors)\n"
- " '-S' indicates the consecutive number of bytes that must contain only zeros\n"
- " for qemu-img to create a sparse image during conversion\n"
+ " '-S' indicates the consecutive number of bytes (defaults to 4k) that must\n"
+ " contain only zeros for qemu-img to create a sparse image during\n"
+ " conversion. If the number of bytes is 0, the source will not be scanned for\n"
+ " unallocated or zero sectors, and the destination image will always be\n"
+ " fully allocated\n"
+ " images will always be fully allocated\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"
@@ -1465,7 +1469,7 @@ static int img_convert(int argc, char **argv)
/* signal EOF to align */
bdrv_write_compressed(out_bs, 0, NULL, 0);
} else {
- int has_zero_init = bdrv_has_zero_init(out_bs);
+ int has_zero_init = min_sparse ? bdrv_has_zero_init(out_bs) : 0;
sector_num = 0; // total number of sectors converted so far
nb_sectors = total_sectors - sector_num;
diff --git a/qemu-img.texi b/qemu-img.texi
index 768054e900..da36975d70 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -193,6 +193,12 @@ Image conversion is also useful to get smaller image when using a
growable format such as @code{qcow} or @code{cow}: the empty sectors
are detected and suppressed from the destination image.
+@var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
+that must contain only zeros for qemu-img to create a sparse image during
+conversion. If @var{sparse_size} is 0, the source will not be scanned for
+unallocated or zero sectors, and the destination image will always be
+fully allocated.
+
You can use the @var{backing_file} option to force the output image to be
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,