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| author | Alberto Garcia <berto@igalia.com> | 2020-10-26 17:58:26 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2020-10-27 15:26:20 +0100 |
| commit | d40f4a565aa64a1ef1e1ff73caf53d61cac9a67f (patch) | |
| tree | 671c8523f8863d8719707f9cd225f94cf65cba31 | |
| parent | 0c8c4895a6a54ffb7209402b183297c80c868873 (diff) | |
| download | focaccia-qemu-d40f4a565aa64a1ef1e1ff73caf53d61cac9a67f.tar.gz focaccia-qemu-d40f4a565aa64a1ef1e1ff73caf53d61cac9a67f.zip | |
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 <vsementsov@virtuozzo.com> Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <66fa0914a0e2b727ab6d1b63ca773d7cd29a9a9e.1603731354.git.berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/io.c | 8 |
1 files 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; } } |