Re: [Qemu-devel] [PATCH] raw-posix: Fix build without posix_fallocate()

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 29 Sep 2014 17:12:59 +0200
Kevin Wolf <kwolf@redhat.com> wrote:

> Check for the presence of posix_fallocate() in configure and only
> compile in support for PREALLOC_MODE_FALLOC when it's there.
With this patch QEMU builds fine on OS X

Tested-By: Igor Mammedov <imammedo@redhat.com>

> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/raw-posix.c | 18 ++++++++++++++----
>  configure         | 18 ++++++++++++++++++
>  2 files changed, 32 insertions(+), 4 deletions(-)
> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index a253697..86ce4f2 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1416,16 +1416,21 @@ static int raw_create(const char *filename,
> QemuOpts *opts, Error **errp) goto out_close;
>      }
>  
> -    if (prealloc == PREALLOC_MODE_FALLOC) {
> +    switch (prealloc) {
> +#ifdef CONFIG_POSIX_FALLOCATE
> +    case PREALLOC_MODE_FALLOC:
>          /* posix_fallocate() doesn't set errno. */
>          result = -posix_fallocate(fd, 0, total_size);
>          if (result != 0) {
>              error_setg_errno(errp, -result,
>                               "Could not preallocate data for the new
> file"); }
> -    } else if (prealloc == PREALLOC_MODE_FULL) {
> -        buf = g_malloc0(65536);
> +        break;
> +#endif
> +    case PREALLOC_MODE_FULL:
> +    {
>          int64_t num = 0, left = total_size;
> +        buf = g_malloc0(65536);
>  
>          while (left > 0) {
>              num = MIN(left, 65536);
> @@ -1440,10 +1445,15 @@ static int raw_create(const char *filename,
> QemuOpts *opts, Error **errp) }
>          fsync(fd);
>          g_free(buf);
> -    } else if (prealloc != PREALLOC_MODE_OFF) {
> +        break;
> +    }
> +    case PREALLOC_MODE_OFF:
> +        break;
> +    default:
>          result = -EINVAL;
>          error_setg(errp, "Unsupported preallocation mode: %s",
>                     PreallocMode_lookup[prealloc]);
> +        break;
>      }
>  
>  out_close:
> diff --git a/configure b/configure
> index a2c0f2a..681abfc 100755
> --- a/configure
> +++ b/configure
> @@ -3308,6 +3308,21 @@ if compile_prog "" "" ; then
>    fallocate_punch_hole=yes
>  fi
>  
> +# check for posix_fallocate
> +posix_fallocate=no
> +cat > $TMPC << EOF
> +#include <fcntl.h>
> +
> +int main(void)
> +{
> +    posix_fallocate(0, 0, 0);
> +    return 0;
> +}
> +EOF
> +if compile_prog "" "" ; then
> +    posix_fallocate=yes
> +fi
> +
>  # check for sync_file_range
>  sync_file_range=no
>  cat > $TMPC << EOF
> @@ -4522,6 +4537,9 @@ fi
>  if test "$fallocate_punch_hole" = "yes" ; then
>    echo "CONFIG_FALLOCATE_PUNCH_HOLE=y" >> $config_host_mak
>  fi
> +if test "$posix_fallocate" = "yes" ; then
> +  echo "CONFIG_POSIX_FALLOCATE=y" >> $config_host_mak
> +fi
>  if test "$sync_file_range" = "yes" ; then
>    echo "CONFIG_SYNC_FILE_RANGE=y" >> $config_host_mak
>  fi