Limiting each loop iteration of qemu-img map to 1 GB was arbitrary from

the beginning, though it only cut the maximum in half then because the

interface was a signed 32 bit byte count. These days, bdrv_block_status

supports a 64 bit byte count, so the arbitrary limit is even worse.

On file-posix, bdrv_block_status() eventually maps to SEEK_HOLE and

SEEK_DATA, which don't support a limit, but always do all of the work

necessary to find the start of the next hole/data. Much of this work may

be repeated if we don't use this information fully, but query with an

only slightly larger offset in the next loop iteration. Therefore, if

bdrv_block_status() is called in a loop, it should always pass the

full number of bytes that the whole loop is interested in.

This removes the arbitrary limit and speeds up 'qemu-img map'

significantly on heavily fragmented images.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Message-Id: <20200707144629.51235-1-kwolf@redhat.com>

Reviewed-by: Eric Blake <eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

qemu-img.c | 5 +----

1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c

index XXXXXXX..XXXXXXX 100644

--- a/qemu-img.c

+++ b/qemu-img.c

@@ -XXX,XX +XXX,XX @@ static int img_map(int argc, char **argv)

curr.start = start_offset;

while (curr.start + curr.length < length) {

int64_t offset = curr.start + curr.length;

- int64_t n;

+ int64_t n = length - offset;

- /* Probe up to 1 GiB at a time. */

- n = MIN(1 * GiB, length - offset);

ret = get_block_status(bs, offset, n, &next);

-

if (ret < 0) {

error_report("Could not read file metadata: %s", strerror(-ret));

goto out;

--

2.25.4

Especially when O_DIRECT is used with image files so that the page cache

indirection can't cause a merge of allocating requests, the file will

fragment on the file system layer, with a potentially very small

fragment size (this depends on the requests the guest sent).

On Linux, fragmentation can be reduced by setting an extent size hint

when creating the file (at least on XFS, it can't be set any more after

the first extent has been allocated), basically giving raw files a

"cluster size" for allocation.

This adds a create option to set the extent size hint, and changes the

default from not setting a hint to setting it to 1 MB. The main reason

why qcow2 defaults to smaller cluster sizes is that COW becomes more

expensive, which is not an issue with raw files, so we can choose a

larger size. The tradeoff here is only potentially wasted disk space.

For qcow2 (or other image formats) over file-posix, the advantage should

even be greater because they grow sequentially without leaving holes, so

there won't be wasted space. Setting even larger extent size hints for

such images may make sense. This can be done with the new option, but

let's keep the default conservative for now.

The effect is very visible with a test that intentionally creates a

badly fragmented file with qemu-img bench (the time difference while

creating the file is already remarkable) and then looks at the number of

extents and the time a simple "qemu-img map" takes.

Without an extent size hint:

$ ./qemu-img create -f raw -o extent_size_hint=0 ~/tmp/test.raw 10G

Formatting '/home/kwolf/tmp/test.raw', fmt=raw size=10737418240 extent_size_hint=0

$ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 0

Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 0, step size 8192)

Run completed in 25.848 seconds.

$ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 4096

Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 4096, step size 8192)

Run completed in 19.616 seconds.

$ filefrag ~/tmp/test.raw

/home/kwolf/tmp/test.raw: 2000000 extents found

$ time ./qemu-img map ~/tmp/test.raw

Offset Length Mapped to File

0 0x1e8480000 0 /home/kwolf/tmp/test.raw

real 0m1,279s

user 0m0,043s

sys 0m1,226s

With the new default extent size hint of 1 MB:

$ ./qemu-img create -f raw -o extent_size_hint=1M ~/tmp/test.raw 10G

Formatting '/home/kwolf/tmp/test.raw', fmt=raw size=10737418240 extent_size_hint=1048576

$ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 0

Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 0, step size 8192)

Run completed in 11.833 seconds.

$ ./qemu-img bench -f raw -t none -n -w ~/tmp/test.raw -c 1000000 -S 8192 -o 4096

Sending 1000000 write requests, 4096 bytes each, 64 in parallel (starting at offset 4096, step size 8192)

Run completed in 10.155 seconds.

$ filefrag ~/tmp/test.raw

/home/kwolf/tmp/test.raw: 178 extents found

$ time ./qemu-img map ~/tmp/test.raw

Offset Length Mapped to File

0 0x1e8480000 0 /home/kwolf/tmp/test.raw

real 0m0,061s

user 0m0,040s

sys 0m0,014s

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Message-Id: <20200707142329.48303-1-kwolf@redhat.com>

Reviewed-by: Eric Blake <eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

qapi/block-core.json | 11 ++++++----

include/block/block_int.h | 1 +

block/file-posix.c | 42 ++++++++++++++++++++++++++++++++++++++

tests/qemu-iotests/082.out | 16 +++++++++++++++

tests/qemu-iotests/243 | 7 ++++---

tests/qemu-iotests/243.out | 16 +++++++--------

6 files changed, 78 insertions(+), 15 deletions(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json

index XXXXXXX..XXXXXXX 100644

--- a/qapi/block-core.json

+++ b/qapi/block-core.json

@@ -XXX,XX +XXX,XX @@

# falloc (if defined CONFIG_POSIX_FALLOCATE),

# full (if defined CONFIG_POSIX))

# @nocow: Turn off copy-on-write (valid only on btrfs; default: off)

+# @extent-size-hint: Extent size hint to add to the image file; 0 for not

+# adding an extent size hint (default: 1 MB, since 5.1)

#

# Since: 2.12

##

{ 'struct': 'BlockdevCreateOptionsFile',

- 'data': { 'filename': 'str',

- 'size': 'size',

- '*preallocation': 'PreallocMode',

- '*nocow': 'bool' } }

+ 'data': { 'filename': 'str',

+ 'size': 'size',

+ '*preallocation': 'PreallocMode',

+ '*nocow': 'bool',

+ '*extent-size-hint': 'size'} }

##

# @BlockdevCreateOptionsGluster:

diff --git a/include/block/block_int.h b/include/block/block_int.h

index XXXXXXX..XXXXXXX 100644

--- a/include/block/block_int.h

+++ b/include/block/block_int.h

@@ -XXX,XX +XXX,XX @@

#define BLOCK_OPT_ADAPTER_TYPE "adapter_type"

#define BLOCK_OPT_REDUNDANCY "redundancy"

#define BLOCK_OPT_NOCOW "nocow"

+#define BLOCK_OPT_EXTENT_SIZE_HINT "extent_size_hint"

#define BLOCK_OPT_OBJECT_SIZE "object_size"

#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"

#define BLOCK_OPT_DATA_FILE "data_file"

diff --git a/block/file-posix.c b/block/file-posix.c

index XXXXXXX..XXXXXXX 100644

--- a/block/file-posix.c

+++ b/block/file-posix.c

@@ -XXX,XX +XXX,XX @@

#include "block/block_int.h"

#include "qemu/module.h"

#include "qemu/option.h"

+#include "qemu/units.h"

#include "trace.h"

#include "block/thread-pool.h"

#include "qemu/iov.h"

@@ -XXX,XX +XXX,XX @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)

if (!file_opts->has_preallocation) {

file_opts->preallocation = PREALLOC_MODE_OFF;

}

+ if (!file_opts->has_extent_size_hint) {

+ file_opts->extent_size_hint = 1 * MiB;

+ }

+ if (file_opts->extent_size_hint > UINT32_MAX) {

+ result = -EINVAL;

+ error_setg(errp, "Extent size hint is too large");

+ goto out;

+ }

/* Create file */

fd = qemu_open(file_opts->filename, O_RDWR | O_CREAT | O_BINARY, 0644);

@@ -XXX,XX +XXX,XX @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)

}

#endif

}

+#ifdef FS_IOC_FSSETXATTR

+ /*

+ * Try to set the extent size hint. Failure is not fatal, and a warning is

+ * only printed if the option was explicitly specified.

+ */

+ {

+ struct fsxattr attr;

+ result = ioctl(fd, FS_IOC_FSGETXATTR, &attr);

+ if (result == 0) {

+ attr.fsx_xflags |= FS_XFLAG_EXTSIZE;

+ attr.fsx_extsize = file_opts->extent_size_hint;

+ result = ioctl(fd, FS_IOC_FSSETXATTR, &attr);

+ }

+ if (result < 0 && file_opts->has_extent_size_hint) {

+ warn_report("Failed to set extent size hint: %s",

+ strerror(errno));

+ }

+ }

+#endif

/* Resize and potentially preallocate the file to the desired

* final size */

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

{

BlockdevCreateOptions options;

int64_t total_size = 0;

+ int64_t extent_size_hint = 0;

+ bool has_extent_size_hint = false;

bool nocow = false;

PreallocMode prealloc;

char *buf = NULL;

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

/* Read out options */

total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),

BDRV_SECTOR_SIZE);

+ if (qemu_opt_get(opts, BLOCK_OPT_EXTENT_SIZE_HINT)) {

+ has_extent_size_hint = true;

+ extent_size_hint =

+ qemu_opt_get_size_del(opts, BLOCK_OPT_EXTENT_SIZE_HINT, -1);

+ }

nocow = qemu_opt_get_bool(opts, BLOCK_OPT_NOCOW, false);

buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);

prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn raw_co_create_opts(BlockDriver *drv,

.preallocation = prealloc,

.has_nocow = true,

.nocow = nocow,

+ .has_extent_size_hint = has_extent_size_hint,

+ .extent_size_hint = extent_size_hint,

},

};

return raw_co_create(&options, errp);

@@ -XXX,XX +XXX,XX @@ static QemuOptsList raw_create_opts = {

#endif

", full)"

},

+ {

+ .name = BLOCK_OPT_EXTENT_SIZE_HINT,

+ .type = QEMU_OPT_SIZE,

+ .help = "Extent size hint for the image file, 0 to disable"

+ },

{ /* end of list */ }

}

};

diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/082.out

+++ b/tests/qemu-iotests/082.out

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

@@ -XXX,XX +XXX,XX @@ Supported options:

encrypt.ivgen-hash-alg=<str> - Name of IV generator hash algorithm

encrypt.key-secret=<str> - ID of secret providing qcow AES key or LUKS passphrase

encryption=<bool (on/off)> - Encrypt the image with format 'aes'. (Deprecated in favor of encrypt.format=aes)

+ extent_size_hint=<size> - Extent size hint for the image file, 0 to disable

lazy_refcounts=<bool (on/off)> - Postpone refcount updates

nocow=<bool (on/off)> - Turn off copy-on-write (valid only on btrfs)

preallocation=<str> - Preallocation mode (allowed values: off, metadata, falloc, full)

diff --git a/tests/qemu-iotests/243 b/tests/qemu-iotests/243

index XXXXXXX..XXXXXXX 100755

--- a/tests/qemu-iotests/243

+++ b/tests/qemu-iotests/243

@@ -XXX,XX +XXX,XX @@ for mode in off metadata falloc full; do

echo "=== preallocation=$mode ==="

echo

- _make_test_img -o "preallocation=$mode" 64M

+ _make_test_img -o "preallocation=$mode,extent_size_hint=0" 64M

printf "File size: "

du -b $TEST_IMG | cut -f1

@@ -XXX,XX +XXX,XX @@ for mode in off metadata falloc full; do

echo "=== External data file: preallocation=$mode ==="

echo

- _make_test_img -o "data_file=$TEST_IMG.data,preallocation=$mode" 64M

+ _make_test_img \

+ -o "data_file=$TEST_IMG.data,preallocation=$mode,extent_size_hint=0" 64M

echo -n "qcow2 file size: "

du -b $TEST_IMG | cut -f1

@@ -XXX,XX +XXX,XX @@ for mode in off metadata falloc full; do

echo -n "qcow2 disk usage: "

[ $(du -B1 $TEST_IMG | cut -f1) -lt 1048576 ] && echo "low" || echo "high"

echo -n "data disk usage: "

- [ $(du -B1 $TEST_IMG.data | cut -f1) -lt 1048576 ] && echo "low" || echo "high"

+ [ $(du -B1 $TEST_IMG.data | cut -f1) -lt 2097152 ] && echo "low" || echo "high"

done

diff --git a/tests/qemu-iotests/243.out b/tests/qemu-iotests/243.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/243.out

+++ b/tests/qemu-iotests/243.out

@@ -XXX,XX +XXX,XX @@ QA output created by 243

=== preallocation=off ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=off

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=off extent_size_hint=0

File size: 196616

Disk usage: low

=== preallocation=metadata ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=metadata

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=metadata extent_size_hint=0

File size: 67436544

Disk usage: low

=== preallocation=falloc ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=falloc

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=falloc extent_size_hint=0

File size: 67436544

Disk usage: high

=== preallocation=full ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=full

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 preallocation=full extent_size_hint=0

File size: 67436544

Disk usage: high

=== External data file: preallocation=off ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=off

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=off extent_size_hint=0

qcow2 file size: 196616

data file size: 67108864

qcow2 disk usage: low

@@ -XXX,XX +XXX,XX @@ data disk usage: low

=== External data file: preallocation=metadata ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=metadata

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=metadata extent_size_hint=0

qcow2 file size: 327680

data file size: 67108864

qcow2 disk usage: low

@@ -XXX,XX +XXX,XX @@ data disk usage: low

=== External data file: preallocation=falloc ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=falloc

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=falloc extent_size_hint=0

qcow2 file size: 327680

data file size: 67108864

qcow2 disk usage: low

@@ -XXX,XX +XXX,XX @@ data disk usage: high

=== External data file: preallocation=full ===

-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=full

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 data_file=TEST_DIR/t.IMGFMT.data preallocation=full extent_size_hint=0

qcow2 file size: 327680

data file size: 67108864

qcow2 disk usage: low

--

2.25.4

From: Eric Blake <eblake@redhat.com>

During 'qemu-img create ... 2>&1', if --quiet is not in force, we can

end up with buffered I/O in stdout that was produced before failure,

but which appears in output after failure. This is confusing; the fix

is to flush stdout prior to attempting anything that might produce an

error message. Several iotests demonstrate the resulting ordering

change now that the merged outputs now reflect chronology. (An even

better fix would be to avoid printf from within block.c altogether,

but that's much more invasive...)

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20200706203954.341758-2-eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

block.c | 1 +

tests/qemu-iotests/049.out | 8 ++++----

tests/qemu-iotests/054.out | 2 +-

tests/qemu-iotests/079.out | 2 +-

tests/qemu-iotests/112.out | 4 ++--

tests/qemu-iotests/259.out | 2 +-

6 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/block.c b/block.c

index XXXXXXX..XXXXXXX 100644

--- a/block.c

+++ b/block.c

@@ -XXX,XX +XXX,XX @@ void bdrv_img_create(const char *filename, const char *fmt,

printf("Formatting '%s', fmt=%s ", filename, fmt);

qemu_opts_print(opts, " ");

puts("");

+ fflush(stdout);

}

ret = bdrv_create(drv, filename, opts, &local_err);

diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/049.out

+++ b/tests/qemu-iotests/049.out

@@ -XXX,XX +XXX,XX @@ qemu-img create -f qcow2 -o compat=1.1 TEST_DIR/t.qcow2 64M

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=1.1 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib

qemu-img create -f qcow2 -o compat=0.42 TEST_DIR/t.qcow2 64M

-qemu-img: TEST_DIR/t.qcow2: Invalid parameter '0.42'

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.42 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib

+qemu-img: TEST_DIR/t.qcow2: Invalid parameter '0.42'

qemu-img create -f qcow2 -o compat=foobar TEST_DIR/t.qcow2 64M

-qemu-img: TEST_DIR/t.qcow2: Invalid parameter 'foobar'

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=foobar cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib

+qemu-img: TEST_DIR/t.qcow2: Invalid parameter 'foobar'

== Check preallocation option ==

@@ -XXX,XX +XXX,XX @@ qemu-img create -f qcow2 -o preallocation=metadata TEST_DIR/t.qcow2 64M

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=metadata lazy_refcounts=off refcount_bits=16 compression_type=zlib

qemu-img create -f qcow2 -o preallocation=1234 TEST_DIR/t.qcow2 64M

-qemu-img: TEST_DIR/t.qcow2: Invalid parameter '1234'

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 cluster_size=65536 preallocation=1234 lazy_refcounts=off refcount_bits=16 compression_type=zlib

+qemu-img: TEST_DIR/t.qcow2: Invalid parameter '1234'

== Check encryption option ==

@@ -XXX,XX +XXX,XX @@ qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=off TEST_DIR/t.qcow2 64M

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=off refcount_bits=16 compression_type=zlib

qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=on TEST_DIR/t.qcow2 64M

-qemu-img: TEST_DIR/t.qcow2: Lazy refcounts only supported with compatibility level 1.1 and above (use version=v3 or greater)

Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat=0.10 cluster_size=65536 lazy_refcounts=on refcount_bits=16 compression_type=zlib

+qemu-img: TEST_DIR/t.qcow2: Lazy refcounts only supported with compatibility level 1.1 and above (use version=v3 or greater)

*** done

diff --git a/tests/qemu-iotests/054.out b/tests/qemu-iotests/054.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/054.out

+++ b/tests/qemu-iotests/054.out

@@ -XXX,XX +XXX,XX @@

QA output created by 054

creating too large image (1 EB)

-qemu-img: TEST_DIR/t.IMGFMT: The image size is too large for file format 'IMGFMT' (try using a larger cluster size)

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1152921504606846976

+qemu-img: TEST_DIR/t.IMGFMT: The image size is too large for file format 'IMGFMT' (try using a larger cluster size)

creating too large image (1 EB) using qcow2.py

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296

diff --git a/tests/qemu-iotests/079.out b/tests/qemu-iotests/079.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/079.out

+++ b/tests/qemu-iotests/079.out

@@ -XXX,XX +XXX,XX @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 preallocation=metadat

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 preallocation=metadata

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 preallocation=metadata

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 preallocation=metadata

-qemu-img: TEST_DIR/t.IMGFMT: Cluster size must be a power of two between 512 and 2048k

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 preallocation=metadata

+qemu-img: TEST_DIR/t.IMGFMT: Cluster size must be a power of two between 512 and 2048k

*** done

diff --git a/tests/qemu-iotests/112.out b/tests/qemu-iotests/112.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/112.out

+++ b/tests/qemu-iotests/112.out

@@ -XXX,XX +XXX,XX @@ QA output created by 112

=== refcount_bits limits ===

-qemu-img: TEST_DIR/t.IMGFMT: Refcount width must be a power of two and may not exceed 64 bits

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

qemu-img: TEST_DIR/t.IMGFMT: Refcount width must be a power of two and may not exceed 64 bits

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 refcount_bits=-1

@@ -XXX,XX +XXX,XX @@ qemu-img: TEST_DIR/t.IMGFMT: Refcount width must be a power of two and may not e

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

qemu-img: TEST_DIR/t.IMGFMT: Refcount width must be a power of two and may not exceed 64 bits

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

+qemu-img: TEST_DIR/t.IMGFMT: Refcount width must be a power of two and may not exceed 64 bits

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

refcount bits: 1

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

@@ -XXX,XX +XXX,XX @@ refcount bits: 16

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

refcount bits: 16

-qemu-img: TEST_DIR/t.IMGFMT: Different refcount widths than 16 bits require compatibility level 1.1 or above (use version=v3 or greater)

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

qemu-img: TEST_DIR/t.IMGFMT: Different refcount widths than 16 bits require compatibility level 1.1 or above (use version=v3 or greater)

Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864

+qemu-img: TEST_DIR/t.IMGFMT: Different refcount widths than 16 bits require compatibility level 1.1 or above (use version=v3 or greater)

=== Snapshot limit on refcount_bits=1 ===

diff --git a/tests/qemu-iotests/259.out b/tests/qemu-iotests/259.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/259.out

+++ b/tests/qemu-iotests/259.out

@@ -XXX,XX +XXX,XX @@ virtual size: 64 MiB (67108864 bytes)

disk size: unavailable

--- Testing creation for which the node would need to grow ---

-qemu-img: TEST_DIR/t.IMGFMT: Could not resize image: Image format driver does not support resize

Formatting 'TEST_DIR/t.IMGFMT', fmt=qcow2 size=67108864 preallocation=metadata

+qemu-img: TEST_DIR/t.IMGFMT: Could not resize image: Image format driver does not support resize

*** done

--

2.25.4

From: Eric Blake <eblake@redhat.com>

It's been two releases since we started warning; time to make the

combination an error as promised. There was no iotest coverage, so

add some.

While touching the documentation, tweak another section heading for

consistent style.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20200706203954.341758-3-eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

docs/system/deprecated.rst | 18 ++++++++----------

qemu-img.c | 4 ++--

tests/qemu-iotests/122 | 7 +++++++

tests/qemu-iotests/122.out | 4 ++++

4 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst

index XXXXXXX..XXXXXXX 100644

--- a/docs/system/deprecated.rst

+++ b/docs/system/deprecated.rst

@@ -XXX,XX +XXX,XX @@ kernel in 2018, and has also been dropped from glibc.

Related binaries

----------------

-``qemu-img convert -n -o`` (since 4.2.0)

-''''''''''''''''''''''''''''''''''''''''

-

-All options specified in ``-o`` are image creation options, so

-they have no effect when used with ``-n`` to skip image creation.

-Silently ignored options can be confusing, so this combination of

-options will be made an error in future versions.

-

Backwards compatibility

-----------------------

@@ -XXX,XX +XXX,XX @@ spec you can use the ``-cpu rv64gcsu,priv_spec=v1.10.0`` command line argument.

Related binaries

----------------

-``qemu-nbd --partition`` (removed in 5.0.0)

-'''''''''''''''''''''''''''''''''''''''''''

+``qemu-nbd --partition`` (removed in 5.0)

+'''''''''''''''''''''''''''''''''''''''''

The ``qemu-nbd --partition $digit`` code (also spelled ``-P``)

could only handle MBR partitions, and never correctly handled logical

@@ -XXX,XX +XXX,XX @@ can be rewritten as::

qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.file.driver=file,file.file.filename=file.qcow2

+``qemu-img convert -n -o`` (removed in 5.1)

+'''''''''''''''''''''''''''''''''''''''''''

+

+All options specified in ``-o`` are image creation options, so

+they are now rejected when used with ``-n`` to skip image creation.

+

Command line options

--------------------

diff --git a/qemu-img.c b/qemu-img.c

index XXXXXXX..XXXXXXX 100644

--- a/qemu-img.c

+++ b/qemu-img.c

@@ -XXX,XX +XXX,XX @@ static int img_convert(int argc, char **argv)

}

if (skip_create && options) {

- warn_report("-o has no effect when skipping image creation");

- warn_report("This will become an error in future QEMU versions.");

+ error_report("-o has no effect when skipping image creation");

+ goto fail_getopt;

}

if (s.has_zero_init && !skip_create) {

diff --git a/tests/qemu-iotests/122 b/tests/qemu-iotests/122

index XXXXXXX..XXXXXXX 100755

--- a/tests/qemu-iotests/122

+++ b/tests/qemu-iotests/122

@@ -XXX,XX +XXX,XX @@ TEST_IMG="$TEST_IMG".orig _make_test_img 64M

# backing file"

$QEMU_IMG convert -O $IMGFMT -B "$TEST_IMG".base -n "$TEST_IMG" "$TEST_IMG".orig

+echo

+echo '=== -n incompatible with -o ==='

+echo

+

+$QEMU_IMG convert -O $IMGFMT -o preallocation=metadata -n \

+     "$TEST_IMG" "$TEST_IMG".orig && echo "unexpected success"

+

# success, all done

echo '*** done'

rm -f $seq.full

diff --git a/tests/qemu-iotests/122.out b/tests/qemu-iotests/122.out

index XXXXXXX..XXXXXXX 100644

--- a/tests/qemu-iotests/122.out

+++ b/tests/qemu-iotests/122.out

@@ -XXX,XX +XXX,XX @@ Images are identical.

Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864

Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=IMGFMT size=67108864

+

+=== -n incompatible with -o ===

+

+qemu-img: -o has no effect when skipping image creation

*** done

--

2.25.4

From: Eric Blake <eblake@redhat.com>

Sheepdog already requires that if backing_file is present, that it be

another sheepdog image (see sd_co_create). Meanwhile, we want to move

towards always being explicit about the backing format for other

drivers where it matters. So for convenience, make qemu-img create -F

sheepdog work, while rejecting all other explicit formats (note that

this is only for QemuOpts usage; there is no change to the QAPI to

allow a format through -blockdev).

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20200706203954.341758-4-eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

block/sheepdog.c | 18 ++++++++++++++++--

1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/block/sheepdog.c b/block/sheepdog.c

index XXXXXXX..XXXXXXX 100644

--- a/block/sheepdog.c

+++ b/block/sheepdog.c

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn sd_co_create_opts(BlockDriver *drv,

Error **errp)

{

BlockdevCreateOptions *create_options = NULL;

- QDict *qdict, *location_qdict;

+ QDict *qdict = NULL, *location_qdict;

Visitor *v;

- char *redundancy;

+ char *redundancy = NULL;

Error *local_err = NULL;

int ret;

+ char *backing_fmt = NULL;

redundancy = qemu_opt_get_del(opts, BLOCK_OPT_REDUNDANCY);

+ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);

+

+ if (backing_fmt && strcmp(backing_fmt, "sheepdog") != 0) {

+ error_setg(errp, "backing_file must be a sheepdog image");

+ ret = -EINVAL;

+ goto fail;

+ }

qdict = qemu_opts_to_qdict(opts, NULL);

qdict_put_str(qdict, "driver", "sheepdog");

@@ -XXX,XX +XXX,XX @@ fail:

qapi_free_BlockdevCreateOptions(create_options);

qobject_unref(qdict);

g_free(redundancy);

+ g_free(backing_fmt);

return ret;

}

@@ -XXX,XX +XXX,XX @@ static QemuOptsList sd_create_opts = {

.type = QEMU_OPT_STRING,

.help = "File name of a base image"

},

+ {

+ .name = BLOCK_OPT_BACKING_FMT,

+ .type = QEMU_OPT_STRING,

+ .help = "Must be 'sheepdog' if present",

+ },

{

.name = BLOCK_OPT_PREALLOC,

.type = QEMU_OPT_STRING,

--

2.25.4

From: Eric Blake <eblake@redhat.com>

vmdk already requires that if backing_file is present, that it be

another vmdk image (see vmdk_co_do_create). Meanwhile, we want to

move towards always being explicit about the backing format for other

drivers where it matters. So for convenience, make qemu-img create -F

vmdk work, while rejecting all other explicit formats (note that this

is only for QemuOpts usage; there is no change to the QAPI to allow a

format through -blockdev).

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20200706203954.341758-5-eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

block/vmdk.c | 14 ++++++++++++++

1 file changed, 14 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c

index XXXXXXX..XXXXXXX 100644

--- a/block/vmdk.c

+++ b/block/vmdk.c

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn vmdk_co_create_opts(BlockDriver *drv,

bool zeroed_grain;

bool compat6;

VMDKCreateOptsData data;

+ char *backing_fmt = NULL;

+

+ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);

+ if (backing_fmt && strcmp(backing_fmt, "vmdk") != 0) {

+ error_setg(errp, "backing_file must be a vmdk image");

+ ret = -EINVAL;

+ goto exit;

+ }

if (filename_decompose(filename, path, prefix, postfix, PATH_MAX, errp)) {

ret = -EINVAL;

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn vmdk_co_create_opts(BlockDriver *drv,

vmdk_co_create_opts_cb, &data, errp);

exit:

+ g_free(backing_fmt);

g_free(adapter_type);

g_free(backing_file);

g_free(hw_version);

@@ -XXX,XX +XXX,XX @@ static QemuOptsList vmdk_create_opts = {

.type = QEMU_OPT_STRING,

.help = "File name of a base image"

},

+ {

+ .name = BLOCK_OPT_BACKING_FMT,

+ .type = QEMU_OPT_STRING,

+ .help = "Must be 'vmdk' if present",

+ },

{

.name = BLOCK_OPT_COMPAT6,

.type = QEMU_OPT_BOOL,

--

2.25.4

From: Eric Blake <eblake@redhat.com>

qcow has no space in the metadata to store a backing format, and there

are existing qcow images backed both by raw or by other formats

(usually qcow) images, reliant on probing to tell the difference. On

the bright side, because we probe every time, raw files are marked as

probed and we thus forbid a commit action into the backing file where

guest-controlled contents could change the result of the probe next

time around (the iotest added here proves that).

Still, allowing the user to specify the backing format during

creation, even if we can't record it, is a good thing. This patch

blindly allows any value that resolves to a known driver, even if the

user's request is a mismatch from what probing finds; then the next

patch will further enhance things to verify that the user's request

matches what we actually probe. With this and the next patch in

place, we will finally be ready to deprecate the creation of images

where a backing format was not explicitly specified by the user.

Note that this is only for QemuOpts usage; there is no change to the

QAPI to allow a format through -blockdev.

Add a new iotest 293 just for qcow, to demonstrate the latest

behavior, and to make it easier to show the improvements made in the

next patch.

Signed-off-by: Eric Blake <eblake@redhat.com>

Message-Id: <20200706203954.341758-6-eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

block/qcow.c | 20 ++++++++-

tests/qemu-iotests/293 | 88 ++++++++++++++++++++++++++++++++++++++

tests/qemu-iotests/293.out | 60 ++++++++++++++++++++++++++

tests/qemu-iotests/group | 1 +

4 files changed, 168 insertions(+), 1 deletion(-)

create mode 100755 tests/qemu-iotests/293

create mode 100644 tests/qemu-iotests/293.out

diff --git a/block/qcow.c b/block/qcow.c

index XXXXXXX..XXXXXXX 100644

--- a/block/qcow.c

+++ b/block/qcow.c

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,

{

BlockdevCreateOptions *create_options = NULL;

BlockDriverState *bs = NULL;

- QDict *qdict;

+ QDict *qdict = NULL;

Visitor *v;

const char *val;

Error *local_err = NULL;

int ret;

+ char *backing_fmt;

static const QDictRenames opt_renames[] = {

{ BLOCK_OPT_BACKING_FILE, "backing-file" },

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,

{ NULL, NULL },

};

+ /*

+ * We can't actually store a backing format, but can check that

+ * the user's request made sense.

+ */

+ backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);

+ if (backing_fmt && !bdrv_find_format(backing_fmt)) {

+ error_setg(errp, "unrecognized backing format '%s'", backing_fmt);

+ ret = -EINVAL;

+ goto fail;

+ }

+

/* Parse options and convert legacy syntax */

qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);

@@ -XXX,XX +XXX,XX @@ static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,

ret = 0;

fail:

+ g_free(backing_fmt);

qobject_unref(qdict);

bdrv_unref(bs);

qapi_free_BlockdevCreateOptions(create_options);

@@ -XXX,XX +XXX,XX @@ static QemuOptsList qcow_create_opts = {

.type = QEMU_OPT_STRING,

.help = "File name of a base image"

},

+ {

+ .name = BLOCK_OPT_BACKING_FMT,

+ .type = QEMU_OPT_STRING,

+ .help = "Format of the backing image",

+ },

{

.name = BLOCK_OPT_ENCRYPT,

.type = QEMU_OPT_BOOL,

diff --git a/tests/qemu-iotests/293 b/tests/qemu-iotests/293

new file mode 100755

index XXXXXXX..XXXXXXX

--- /dev/null

+++ b/tests/qemu-iotests/293

@@ -XXX,XX +XXX,XX @@

+#!/usr/bin/env bash

+#

+# Test qcow backing file warnings

+#

+# Copyright (C) 2020 Red Hat, Inc.

+#

+# This program is free software; you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation; either version 2 of the License, or

+# (at your option) any later version.

+#

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

+# GNU General Public License for more details.

+#

+# You should have received a copy of the GNU General Public License

+# along with this program. If not, see <http://www.gnu.org/licenses/>.

+#

+

+seq=`basename $0`

+echo "QA output created by $seq"

+

+status=1 # failure is the default!

+

+_cleanup()

+{

+ _cleanup_test_img

+ _rm_test_img "$TEST_IMG.qcow2"

+}

+trap "_cleanup; exit \$status" 0 1 2 3 15

+

+# get standard environment, filters and checks

+. ./common.rc

+. ./common.filter

+

+_supported_fmt qcow

+_supported_proto file

+_supported_os Linux

+

+size=32M

+

+echo