From 5daa74a6ebce7543aaad178c4061dc087bb4c705 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 4 Sep 2013 19:00:38 +0200 Subject: [PATCH] block: look for zero blocks in bs->file Reviewed-by: Eric Blake Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi --- block.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 3c39769c68..a325efcb21 100644 --- a/block.c +++ b/block.c @@ -3075,7 +3075,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, { int64_t length; int64_t n; - int64_t ret; + int64_t ret, ret2; length = bdrv_getlength(bs); if (length < 0) { @@ -3117,6 +3117,20 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, } } } + + if (bs->file && + (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && + (ret & BDRV_BLOCK_OFFSET_VALID)) { + ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, + *pnum, pnum); + if (ret2 >= 0) { + /* Ignore errors. This is just providing extra information, it + * is useful but not necessary. + */ + ret |= (ret2 & BDRV_BLOCK_ZERO); + } + } + return ret; }