From d40f4a565aa64a1ef1e1ff73caf53d61cac9a67f Mon Sep 17 00:00:00 2001 From: Alberto Garcia Date: Mon, 26 Oct 2020 17:58:26 +0100 Subject: [PATCH] qcow2: Report BDRV_BLOCK_ZERO more accurately in bdrv_co_block_status() If a BlockDriverState supports backing files but has none then any unallocated area reads back as zeroes. bdrv_co_block_status() is only reporting this is if want_zero is true, but this is an inexpensive test and there is no reason not to do it in all cases. Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Alberto Garcia Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <66fa0914a0e2b727ab6d1b63ca773d7cd29a9a9e.1603731354.git.berto@igalia.com> Signed-off-by: Kevin Wolf --- block/io.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/io.c b/block/io.c index 02528b3823..6fe1b275b6 100644 --- a/block/io.c +++ b/block/io.c @@ -2282,17 +2282,17 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { ret |= BDRV_BLOCK_ALLOCATED; - } else if (want_zero && bs->drv->supports_backing) { + } else if (bs->drv->supports_backing) { BlockDriverState *cow_bs = bdrv_cow_bs(bs); - if (cow_bs) { + if (!cow_bs) { + ret |= BDRV_BLOCK_ZERO; + } else if (want_zero) { int64_t size2 = bdrv_getlength(cow_bs); if (size2 >= 0 && offset >= size2) { ret |= BDRV_BLOCK_ZERO; } - } else { - ret |= BDRV_BLOCK_ZERO; } } -- 2.11.0