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Date: Thu, 27 Mar 2014 16:30:13 +0100
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20140327153013.GA2441@stefanha-thinkpad.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v4 1/9] qapi: Add optional field "name" to
 block dirty bitmap
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To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, Benoit Canet <benoit@irqsave.net>

On Thu, Mar 27, 2014 at 05:09:40PM +0800, Fam Zheng wrote:
> @@ -5079,18 +5080,45 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
>      return true;
>  }
>  
> -BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity)
> +BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
> +{
> +    BdrvDirtyBitmap *bm;
> +    QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
> +        if (!strcmp(name, bm->name)) {
> +            return bm;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
> +{
> +    g_free(bitmap->name);
> +    bitmap->name = NULL;
> +}

This looks dangerous since strcmp() does not check for NULL pointers.  I
guess you need to add a check to bdrv_find_dirty_bitmap().

> @@ -5120,6 +5149,8 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
>          info->count = bdrv_get_dirty_count(bs, bm);
>          info->granularity =
>              ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap));
> +        info->has_name = bm->name[0] != '\0';
> +        info->name = g_strdup(bm->name);

This looks dangerous too.  What if ->name is NULL?