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authorMax Reitz <mreitz@redhat.com>2017-06-13 22:20:55 +0200
committerMax Reitz <mreitz@redhat.com>2017-07-11 17:45:01 +0200
commitdc5f690b97ccdffa79fe7169bb26b0ebf06688bf (patch)
treecb7ba74b70e9e8ddcd164a6b03082fb8c69386aa /qemu-img.texi
parent3a691c50f10344b052ad70a4d0ed935276ccca3c (diff)
qemu-img: Expose PreallocMode for resizing
Add a --preallocation command line option to qemu-img resize which can be used to set the PreallocMode parameter of blk_truncate(). While touching this code, fix the fact that we did not handle errors returned by blk_getlength(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170613202107.10125-5-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'qemu-img.texi')
-rw-r--r--qemu-img.texi7
1 files changed, 6 insertions, 1 deletions
diff --git a/qemu-img.texi b/qemu-img.texi
index a2f45199d2..f11f6036ad 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -529,7 +529,7 @@ qemu-img rebase -b base.img diff.qcow2
At this point, @code{modified.img} can be discarded, since
@code{base.img + diff.qcow2} contains the same information.
-@item resize @var{filename} [+ | -]@var{size}
+@item resize [--preallocation=@var{prealloc}] @var{filename} [+ | -]@var{size}
Change the disk image as if it had been created with @var{size}.
@@ -541,6 +541,11 @@ After using this command to grow a disk image, you must use file system and
partitioning tools inside the VM to actually begin using the new space on the
device.
+When growing an image, the @code{--preallocation} option may be used to specify
+how the additional image area should be allocated on the host. See the format
+description in the @code{NOTES} section which values are allowed. Using this
+option may result in slightly more data being allocated than necessary.
+
@item amend [-p] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
Amends the image format specific @var{options} for the image file