Re: [Qemu-devel] [PATCH v13 4/6] qapi: introduce PreallocMode and a new PreallocMode full.

[Max Reitz <mreitz@redhat.com>]

On 29.08.2014 10:33, Hu Tao wrote:
> This patch prepares for the subsequent patches.
>
> Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> ---
>   block/qcow2.c              | 23 +++++++++++++++--------
>   qapi/block-core.json       | 16 ++++++++++++++++
>   tests/qemu-iotests/049.out |  2 +-
>   3 files changed, 32 insertions(+), 9 deletions(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index cf27c3f..95fb240 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -30,6 +30,7 @@
>   #include "qemu/error-report.h"
>   #include "qapi/qmp/qerror.h"
>   #include "qapi/qmp/qbool.h"
> +#include "qapi/util.h"
>   #include "trace.h"
>   #include "qemu/option_int.h"
>   
> @@ -1738,7 +1739,7 @@ static int preallocate(BlockDriverState *bs)
>   
>   static int qcow2_create2(const char *filename, int64_t total_size,
>                            const char *backing_file, const char *backing_format,
> -                         int flags, size_t cluster_size, int prealloc,
> +                         int flags, size_t cluster_size, PreallocMode prealloc,
>                            QemuOpts *opts, int version,
>                            Error **errp)
>   {
> @@ -1915,7 +1916,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
>       uint64_t size = 0;
>       int flags = 0;
>       size_t cluster_size = DEFAULT_CLUSTER_SIZE;
> -    int prealloc = 0;
> +    PreallocMode prealloc = PREALLOC_MODE_OFF;
>       int version = 3;
>       Error *local_err = NULL;
>       int ret;
> @@ -1931,12 +1932,11 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
>       cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
>                                            DEFAULT_CLUSTER_SIZE);
>       buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
> -    if (!buf || !strcmp(buf, "off")) {
> -        prealloc = 0;
> -    } else if (!strcmp(buf, "metadata")) {
> -        prealloc = 1;
> -    } else {
> -        error_setg(errp, "Invalid preallocation mode: '%s'", buf);
> +    prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
> +                               PREALLOC_MODE_MAX, PREALLOC_MODE_OFF,
> +                               &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
>           ret = -EINVAL;
>           goto finish;
>       }
> @@ -1958,6 +1958,13 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
>           flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
>       }
>   
> +    if (prealloc && prealloc != PREALLOC_MODE_METADATA) {
> +        ret = -1;

Since the return value is expected to be -errno, I'd propose "ret = 
-EINVAL;" here. With that fixed (or a good explanation why we want -1 here):

Reviewed-by: Max Reitz <mreitz@redhat.com>

> +        error_setg(errp, "Unsupported preallocate mode: %s",
> +                   PreallocMode_lookup[prealloc]);
> +        goto finish;
> +    }
> +
>       if (backing_file && prealloc) {
>           error_setg(errp, "Backing file and preallocation cannot be used at "
>                      "the same time");
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index fb74c56..543b00b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1679,3 +1679,19 @@
>               'len'   : 'int',
>               'offset': 'int',
>               'speed' : 'int' } }
> +
> +# @PreallocMode
> +#
> +# Preallocation mode of QEMU image file
> +#
> +# @off: no preallocation
> +# @metadata: preallocate only for metadata
> +# @full: preallocate all data by calling posix_fallocate() if it is
> +#        available, otherwise by writing zeros to device to ensure disk
> +#        space is really available. @full preallocation also sets up
> +#        metadata correctly.
> +#
> +# Since 2.2
> +##
> +{ 'enum': 'PreallocMode',
> +  'data': [ 'off', 'metadata', 'full' ] }
> diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
> index 71ca44d..09ca0ae 100644
> --- a/tests/qemu-iotests/049.out
> +++ b/tests/qemu-iotests/049.out
> @@ -179,7 +179,7 @@ qemu-img create -f qcow2 -o preallocation=metadata TEST_DIR/t.qcow2 64M
>   Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off
>   
>   qemu-img create -f qcow2 -o preallocation=1234 TEST_DIR/t.qcow2 64M
> -qemu-img: TEST_DIR/t.qcow2: Invalid preallocation mode: '1234'
> +qemu-img: TEST_DIR/t.qcow2: invalid parameter value: 1234
>   Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='1234' lazy_refcounts=off
>   
>   == Check encryption option ==