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Date: Fri, 24 Jan 2014 16:39:11 +0100
From: =?iso-8859-1?Q?Beno=EEt?= Canet <benoit.canet@irqsave.net>
Message-ID: <20140124153911.GC3087@irqsave.net>
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Subject: Re: [Qemu-devel] [PATCH] block: Fix bdrv_commit return value
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To: Kevin Wolf <kwolf@redhat.com>
Cc: jcody@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com

Le Friday 24 Jan 2014 =E0 14:08:21 (+0100), Kevin Wolf a =E9crit :
> bdrv_commit() could return 0 or 1 on success, depending on whether or
> now the last sector was allocated in the overlay and whether the overla=
y
> format had a .bdrv_make_empty callback.
>=20
> Most callers ignored it, but qemu-img commit would print an error
> message while the operation actually succeeded.
>=20
> Also clean up the handling of I/O errors to return the real error code
> instead of -EIO.
>=20
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
>=20
> diff --git a/block.c b/block.c
> index 3e0994b..7d22ca9 100644
> --- a/block.c
> +++ b/block.c
> @@ -2061,13 +2061,13 @@ int bdrv_commit(BlockDriverState *bs)
>              goto ro_cleanup;
>          }
>          if (ret) {
> -            if (bdrv_read(bs, sector, buf, n) !=3D 0) {
> -                ret =3D -EIO;
> +            ret =3D bdrv_read(bs, sector, buf, n);
> +            if (ret < 0) {
>                  goto ro_cleanup;
>              }
> =20
> -            if (bdrv_write(bs->backing_hd, sector, buf, n) !=3D 0) {
> -                ret =3D -EIO;
> +            ret =3D bdrv_write(bs->backing_hd, sector, buf, n);
> +            if (ret < 0) {
>                  goto ro_cleanup;
>              }
>          }
> @@ -2075,6 +2075,9 @@ int bdrv_commit(BlockDriverState *bs)
> =20
>      if (drv->bdrv_make_empty) {
>          ret =3D drv->bdrv_make_empty(bs);
> +        if (ret < 0) {
> +            goto ro_cleanup;
> +        }
>          bdrv_flush(bs);
>      }
> =20
> @@ -2082,9 +2085,11 @@ int bdrv_commit(BlockDriverState *bs)
>       * Make sure all data we wrote to the backing device is actually
>       * stable on disk.
>       */
> -    if (bs->backing_hd)
> +    if (bs->backing_hd) {
>          bdrv_flush(bs->backing_hd);
> +    }
> =20
> +    ret =3D 0;
>  ro_cleanup:
>      g_free(buf);
> =20
> --=20
> 1.8.1.4
>=20
>=20

the !=3D 0 in "if (bdrv_read(bs, sector, buf, n) !=3D 0) {" was really od=
d.

Reviewed-by: Benoit Canet <benoit@irqsave.net>