block: Do not truncate file node when formatting

There is no reason why the format drivers need to truncate the protocol
node when formatting it.  When using the old .bdrv_co_create_ops()
interface, the file will be created with no size option anyway, which
generally gives it a size of 0.  (Exceptions are block devices, which
cannot be truncated anyway.)

When using blockdev-create, the user must have given the file node some
size anyway, so there is no reason why we should override that.

qed is an exception, it needs the file to start completely empty (as
explained by c743849bee7333c7ef256b7e12e34ed6f907064f).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-4-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

diff --git a/block/parallels.c b/block/parallels.c
index 7cd2714b69f567c3f2393d03ebae772dbe15901f..905cac35c6942e61f12e4099e8bc3d3867856a13 100644 (file)
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -563,11 +563,6 @@ static int coroutine_fn parallels_co_create(BlockdevCreateOptions* opts,
     blk_set_allow_write_beyond_eof(blk, true);
 
     /* Create image format */
-    ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp);
-    if (ret < 0) {
-        goto out;
-    }
-
     bat_entries = DIV_ROUND_UP(total_size, cl_size);
     bat_sectors = DIV_ROUND_UP(bat_entry_off(bat_entries), cl_size);
     bat_sectors = (bat_sectors *  cl_size) >> BDRV_SECTOR_BITS;

diff --git a/block/qcow.c b/block/qcow.c
index 5bdf72ba33ce784c1d69aed89c52e15252ab9412..17705015ca95368a2d3bc2b2b072cd96701e1a82 100644 (file)
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -858,11 +858,6 @@ static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
     blk_set_allow_write_beyond_eof(qcow_blk, true);
 
     /* Create image format */
-    ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp);
-    if (ret < 0) {
-        goto exit;
-    }
-
     memset(&header, 0, sizeof(header));
     header.magic = cpu_to_be32(QCOW_MAGIC);
     header.version = cpu_to_be32(QCOW_VERSION);

diff --git a/block/qcow2.c b/block/qcow2.c
index 8d4f38ae744e63eee390730e7467e913dc608951..bf29d1c46091567559460309fff63a287793781e 100644 (file)
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3391,12 +3391,6 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
     }
     blk_set_allow_write_beyond_eof(blk, true);
 
-    /* Clear the protocol layer and preallocate it if necessary */
-    ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp);
-    if (ret < 0) {
-        goto out;
-    }
-
     /* Write the header */
     QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
     header = g_malloc0(cluster_size);