block.c | 73 +++++++++++++++++++++++----------------------- qemu-img-cmds.hx | 4 +-- qemu-img.c | 16 ++++++---- tests/qemu-iotests/082 | 4 +-- tests/qemu-iotests/082.out | 4 +-- 5 files changed, 54 insertions(+), 47 deletions(-)
Or, rather, force the open of a backing image if one was specified
for creation. Using a similar -unsafe option as rebase, allow qemu-img
to ignore the backing file validation if possible.
It may not always be possible, as in the existing case when a filesize
for the new image was not specified.
This is accomplished by shifting around the conditionals in
bdrv_img_create, such that a backing file is always opened unless we
provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
when -u is provided to create.
Sorry for the heinous looking diffstat, but it's mostly whitespace.
Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786
Signed-off-by: John Snow <jsnow@redhat.com>
---
v3: Rebased
v2: Rebased for 2.10
Corrected some of my less cromulent grammar
block.c | 73 +++++++++++++++++++++++-----------------------
qemu-img-cmds.hx | 4 +--
qemu-img.c | 16 ++++++----
tests/qemu-iotests/082 | 4 +--
tests/qemu-iotests/082.out | 4 +--
5 files changed, 54 insertions(+), 47 deletions(-)
diff --git a/block.c b/block.c
index a45b9b5..3c3df54 100644
--- a/block.c
+++ b/block.c
@@ -4275,37 +4275,37 @@ void bdrv_img_create(const char *filename, const char *fmt,
// The size for the image must always be specified, with one exception:
// If we are using a backing file, we can obtain the size from there
size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
- if (size == -1) {
- if (backing_file) {
- BlockDriverState *bs;
- char *full_backing = g_new0(char, PATH_MAX);
- int64_t size;
- int back_flags;
- QDict *backing_options = NULL;
-
- bdrv_get_full_backing_filename_from_filename(filename, backing_file,
- full_backing, PATH_MAX,
- &local_err);
- if (local_err) {
- g_free(full_backing);
- goto out;
- }
-
- /* backing files always opened read-only */
- back_flags = flags;
- back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
-
- if (backing_fmt) {
- backing_options = qdict_new();
- qdict_put_str(backing_options, "driver", backing_fmt);
- }
-
- bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
- &local_err);
+ if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
+ BlockDriverState *bs;
+ char *full_backing = g_new0(char, PATH_MAX);
+ int back_flags;
+ QDict *backing_options = NULL;
+
+ bdrv_get_full_backing_filename_from_filename(filename, backing_file,
+ full_backing, PATH_MAX,
+ &local_err);
+ if (local_err) {
g_free(full_backing);
- if (!bs) {
- goto out;
- }
+ goto out;
+ }
+
+ /* backing files always opened read-only */
+ back_flags = flags;
+ back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
+
+ if (backing_fmt) {
+ backing_options = qdict_new();
+ qdict_put_str(backing_options, "driver", backing_fmt);
+ }
+
+ bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
+ &local_err);
+ g_free(full_backing);
+ if (!bs) {
+ goto out;
+ }
+
+ if (size == -1) {
size = bdrv_getlength(bs);
if (size < 0) {
error_setg_errno(errp, -size, "Could not get size of '%s'",
@@ -4313,14 +4313,15 @@ void bdrv_img_create(const char *filename, const char *fmt,
bdrv_unref(bs);
goto out;
}
-
qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort);
-
- bdrv_unref(bs);
- } else {
- error_setg(errp, "Image creation needs a size parameter");
- goto out;
}
+
+ bdrv_unref(bs);
+ }
+
+ if (size == -1) {
+ error_setg(errp, "Image creation needs a size parameter");
+ goto out;
}
if (!quiet) {
diff --git a/qemu-img-cmds.hx b/qemu-img-cmds.hx
index bf4ce59..1d230c6 100644
--- a/qemu-img-cmds.hx
+++ b/qemu-img-cmds.hx
@@ -22,9 +22,9 @@ STEXI
ETEXI
DEF("create", img_create,
- "create [-q] [--object objectdef] [-f fmt] [-b backing_file] [-F backing_fmt] [-o options] filename [size]")
+ "create [-q] [--object objectdef] [-f fmt] [-b backing_file] [-F backing_fmt] [-u] [-o options] filename [size]")
STEXI
-@item create [--object @var{objectdef}] [-q] [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-o @var{options}] @var{filename} [@var{size}]
+@item create [--object @var{objectdef}] [-q] [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-u] [-o @var{options}] @var{filename} [@var{size}]
ETEXI
DEF("commit", img_commit,
diff --git a/qemu-img.c b/qemu-img.c
index f3b0ab4..c7cd6d4 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -145,9 +145,11 @@ static void QEMU_NORETURN help(void)
" 'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n"
" instead\n"
" '-c' indicates that target image must be compressed (qcow format only)\n"
- " '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
- " match exactly. The image doesn't need a working backing file before\n"
- " rebasing in this case (useful for renaming the backing file)\n"
+ " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and new\n"
+ " backing file match exactly. The image doesn't need a working backing file\n"
+ " before rebasing in this case (useful for renaming the backing file)\n"
+ " For image creation, allow creating without attempting to"
+ " open the backing file.\n"
" '-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"
@@ -409,6 +411,7 @@ static int img_create(int argc, char **argv)
char *options = NULL;
Error *local_err = NULL;
bool quiet = false;
+ int flags = 0;
for(;;) {
static const struct option long_options[] = {
@@ -416,7 +419,7 @@ static int img_create(int argc, char **argv)
{"object", required_argument, 0, OPTION_OBJECT},
{0, 0, 0, 0}
};
- c = getopt_long(argc, argv, ":F:b:f:he6o:q",
+ c = getopt_long(argc, argv, ":F:b:f:he6o:qu",
long_options, NULL);
if (c == -1) {
break;
@@ -464,6 +467,9 @@ static int img_create(int argc, char **argv)
case 'q':
quiet = true;
break;
+ case 'u':
+ flags |= BDRV_O_NO_BACKING;
+ break;
case OPTION_OBJECT: {
QemuOpts *opts;
opts = qemu_opts_parse_noisily(&qemu_object_opts,
@@ -516,7 +522,7 @@ static int img_create(int argc, char **argv)
}
bdrv_img_create(filename, fmt, base_filename, base_fmt,
- options, img_size, 0, quiet, &local_err);
+ options, img_size, flags, quiet, &local_err);
if (local_err) {
error_reportf_err(local_err, "%s: ", filename);
goto fail;
diff --git a/tests/qemu-iotests/082 b/tests/qemu-iotests/082
index ad1d9fa..d5c83d4 100755
--- a/tests/qemu-iotests/082
+++ b/tests/qemu-iotests/082
@@ -85,8 +85,8 @@ run_qemu_img create -f $IMGFMT -o cluster_size=4k -o help "$TEST_IMG" $size
run_qemu_img create -f $IMGFMT -o cluster_size=4k -o \? "$TEST_IMG" $size
# Looks like a help option, but is part of the backing file name
-run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG",,help "$TEST_IMG" $size
-run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG",,\? "$TEST_IMG" $size
+run_qemu_img create -f $IMGFMT -u -o backing_file="$TEST_IMG",,help "$TEST_IMG" $size
+run_qemu_img create -f $IMGFMT -u -o backing_file="$TEST_IMG",,\? "$TEST_IMG" $size
# Try to trick qemu-img into creating escaped commas
run_qemu_img create -f $IMGFMT -o backing_file="$TEST_IMG", -o help "$TEST_IMG" $size
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index a952330..f2732e4 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -146,10 +146,10 @@ lazy_refcounts Postpone refcount updates
refcount_bits Width of a reference count entry in bits
nocow Turn off copy-on-write (valid only on btrfs)
-Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M
+Testing: create -f qcow2 -u -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M
Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file=TEST_DIR/t.qcow2,,help encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
-Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 128M
+Testing: create -f qcow2 -u -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 128M
Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file=TEST_DIR/t.qcow2,,? encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2, -o help TEST_DIR/t.qcow2 128M
--
2.9.3
On 05/11/2017 10:11 AM, John Snow wrote:
> Or, rather, force the open of a backing image if one was specified
> for creation. Using a similar -unsafe option as rebase, allow qemu-img
> to ignore the backing file validation if possible.
>
> It may not always be possible, as in the existing case when a filesize
> for the new image was not specified.
>
> This is accomplished by shifting around the conditionals in
> bdrv_img_create, such that a backing file is always opened unless we
> provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
> when -u is provided to create.
>
> Sorry for the heinous looking diffstat, but it's mostly whitespace.
>
> Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
> v3: Rebased
>
> +++ b/qemu-img.c
> @@ -145,9 +145,11 @@ static void QEMU_NORETURN help(void)
> " 'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n"
> " instead\n"
> " '-c' indicates that target image must be compressed (qcow format only)\n"
> - " '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
> - " match exactly. The image doesn't need a working backing file before\n"
> - " rebasing in this case (useful for renaming the backing file)\n"
> + " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and new\n"
> + " backing file match exactly. The image doesn't need a working backing file\n"
> + " before rebasing in this case (useful for renaming the backing file)\n"
> + " For image creation, allow creating without attempting to"
> + " open the backing file.\n"
You forgot to fix my v2 review comments ('.', \n)
With that (actually) fixed,
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
On 05/11/2017 11:17 AM, Eric Blake wrote:
> On 05/11/2017 10:11 AM, John Snow wrote:
>> Or, rather, force the open of a backing image if one was specified
>> for creation. Using a similar -unsafe option as rebase, allow qemu-img
>> to ignore the backing file validation if possible.
>>
>> It may not always be possible, as in the existing case when a filesize
>> for the new image was not specified.
>>
>> This is accomplished by shifting around the conditionals in
>> bdrv_img_create, such that a backing file is always opened unless we
>> provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
>> when -u is provided to create.
>>
>> Sorry for the heinous looking diffstat, but it's mostly whitespace.
>>
>> Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786
>>
>> Signed-off-by: John Snow <jsnow@redhat.com>
>> ---
>> v3: Rebased
>>
>
>> +++ b/qemu-img.c
>> @@ -145,9 +145,11 @@ static void QEMU_NORETURN help(void)
>> " 'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n"
>> " instead\n"
>> " '-c' indicates that target image must be compressed (qcow format only)\n"
>> - " '-u' enables unsafe rebasing. It is assumed that old and new backing file\n"
>> - " match exactly. The image doesn't need a working backing file before\n"
>> - " rebasing in this case (useful for renaming the backing file)\n"
>> + " '-u' allows unsafe backing chains. For rebasing, it is assumed that old and new\n"
>> + " backing file match exactly. The image doesn't need a working backing file\n"
>> + " before rebasing in this case (useful for renaming the backing file)\n"
>> + " For image creation, allow creating without attempting to"
>> + " open the backing file.\n"
>
> You forgot to fix my v2 review comments ('.', \n)
>
%*(#$)@%
Stand by...
© 2016 - 2024 Red Hat, Inc.