Re: [Qemu-devel] [PATCH v2 2/5] qcow2: Add qcow2_signal_corruption()

["Benoît Canet" <benoit.canet@irqsave.net>]

The Friday 05 Sep 2014 à 16:07:16 (+0200), Max Reitz wrote :
> Add a helper function for easily marking an image corrupt (on fatal
> corruptions) while outputting an informative message to stderr and via
> QAPI.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/qcow2.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  block/qcow2.h |  5 +++++
>  2 files changed, 53 insertions(+)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index f9e045f..fc4217b 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -30,6 +30,8 @@
>  #include "qemu/error-report.h"
>  #include "qapi/qmp/qerror.h"
>  #include "qapi/qmp/qbool.h"
> +#include "qapi/qmp/types.h"
> +#include "qapi-event.h"
>  #include "trace.h"
>  #include "qemu/option_int.h"
>  
> @@ -2478,6 +2480,52 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts)
>      return 0;
>  }
>  
> +/*
> + * If offset or size are negative, respectively, they will not be included in
> + * the BLOCK_IMAGE_CORRUPTED event emitted.
> + * fatal will be ignored for read-only BDS; corruptions found there will always
> + * be considered non-fatal.
> + */
> +void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
> +                             int64_t size, const char *message_format, ...)
> +{
> +    BDRVQcowState *s = bs->opaque;
> +    char *message;
> +    va_list ap;
> +
> +    fatal = fatal && !bs->read_only;
> +
> +    if (s->signaled_corruption &&
> +        (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
> +    {
> +        return;
> +    }
> +
> +    va_start(ap, message_format);
> +    message = g_strdup_vprintf(message_format, ap);
> +    va_end(ap);
> +
> +    if (fatal) {
> +        fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
> +                "corruption events will be suppressed\n", message);
> +    } else {
> +        fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
> +                "corruption events will be suppressed\n", message);
> +    }
> +
> +    qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), message,
> +                                          offset >= 0, offset, size >= 0, size,
> +                                          fatal, &error_abort);
> +    g_free(message);
> +
> +    if (fatal) {
> +        qcow2_mark_corrupt(bs);
> +        bs->drv = NULL; /* make BDS unusable */
> +    }
> +
> +    s->signaled_corruption = true;
> +}
> +
>  static QemuOptsList qcow2_create_opts = {
>      .name = "qcow2-create-opts",
>      .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 6aeb7ea..7b7b6a6 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -261,6 +261,7 @@ typedef struct BDRVQcowState {
>      bool discard_passthrough[QCOW2_DISCARD_MAX];
>  
>      int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
> +    bool signaled_corruption;
>  
>      uint64_t incompatible_features;
>      uint64_t compatible_features;
> @@ -477,6 +478,10 @@ int qcow2_mark_corrupt(BlockDriverState *bs);
>  int qcow2_mark_consistent(BlockDriverState *bs);
>  int qcow2_update_header(BlockDriverState *bs);
>  
> +void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
> +                             int64_t size, const char *message_format, ...)
> +                             GCC_FMT_ATTR(5, 6);
> +
>  /* qcow2-refcount.c functions */
>  int qcow2_refcount_init(BlockDriverState *bs);
>  void qcow2_refcount_close(BlockDriverState *bs);
> -- 
> 2.1.0
> 
> 
Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>