Re: [Qemu-devel] [PATCH] qcow2: Fix segfault in qcow2_invalidate_cache

[Paolo Bonzini <pbonzini@redhat.com>]

Il 18/03/2013 13:10, Kevin Wolf ha scritto:
> Need to pass an options QDict to qcow2_open() now. This fixes a segfault
> on the migration target with qcow2.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/qcow2.c | 12 ++++++++++--
>  block/qcow2.h |  3 +++
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index b90dd9e..7fcdc62 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -29,6 +29,7 @@
>  #include "block/qcow2.h"
>  #include "qemu/error-report.h"
>  #include "qapi/qmp/qerror.h"
> +#include "qapi/qmp/qbool.h"
>  #include "trace.h"
>  
>  /*
> @@ -520,7 +521,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
>          goto fail;
>      }
>  
> -    s->use_lazy_refcounts = qemu_opt_get_bool(opts, "lazy_refcounts",
> +    s->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
>          (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));

Why not add

   s->use_lazy_refcounts ||

to the default, and just use an empty QDict in qcow2_invalidate_cache?

Paolo

>  
>      qemu_opts_del(opts);
> @@ -934,6 +935,7 @@ static void qcow2_invalidate_cache(BlockDriverState *bs)
>      AES_KEY aes_encrypt_key;
>      AES_KEY aes_decrypt_key;
>      uint32_t crypt_method = 0;
> +    QDict *options;
>  
>      /*
>       * Backing files are read-only which makes all of their metadata immutable,
> @@ -948,8 +950,14 @@ static void qcow2_invalidate_cache(BlockDriverState *bs)
>  
>      qcow2_close(bs);
>  
> +    options = qdict_new();
> +    qdict_put(options, QCOW2_OPT_LAZY_REFCOUNTS,
> +              qbool_from_int(s->use_lazy_refcounts));
> +
>      memset(s, 0, sizeof(BDRVQcowState));
> -    qcow2_open(bs, NULL, flags);
> +    qcow2_open(bs, options, flags);
> +
> +    QDECREF(options);
>  
>      if (crypt_method) {
>          s->crypt_method = crypt_method;
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 103abdb..e4b5e11 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -58,6 +58,9 @@
>  
>  #define DEFAULT_CLUSTER_SIZE 65536
>  
> +
> +#define QCOW2_OPT_LAZY_REFCOUNTS "lazy_refcounts"
> +
>  typedef struct QCowHeader {
>      uint32_t magic;
>      uint32_t version;
>