Commit e7b88252f3 for qemu.org

commit e7b88252f302ff2cee2c934122a5e137b18ab2d9
Author: Hanna Czenczek <hreitz@redhat.com>
Date:   Mon Mar 9 16:08:44 2026 +0100

    iotests/308: Use conv=notrunc to test growability

    Without conv=notrunc, dd will automatically truncate the output file to
    the @seek value at least.  We want to test post-EOF I/O, not truncate,
    so pass conv=notrunc.

    (It does not make a difference in practice because we only seek to the
    EOF, so the truncate effectively does nothing, but this is still
    cleaner.)

    Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
    Message-ID: <20260309150856.26800-14-hreitz@redhat.com>
    Reviewed-by: Kevin Wolf <kwolf@redhat.com>
    Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/tests/qemu-iotests/308 b/tests/qemu-iotests/308
index 033d5cbe22..6ecb275555 100755
--- a/tests/qemu-iotests/308
+++ b/tests/qemu-iotests/308
@@ -296,7 +296,8 @@ orig_disk_usage=$(disk_usage "$TEST_IMG")
 # Should fail (exports are non-growable by default)
 # (Note that qemu-io can never write beyond the EOF, so we have to use
 # dd here)
-dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$orig_len 2>&1 \
+dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$orig_len \
+    conv=notrunc 2>&1 \
     | _filter_testdir | _filter_imgfmt

 echo
@@ -333,7 +334,7 @@ fuse_export_add \
     'node-protocol'

 # Now we should be able to write beyond the EOF
-dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$new_len 2>&1 \
+dd if=/dev/zero of="$EXT_MP" bs=1 count=64k seek=$new_len conv=notrunc 2>&1 \
     | _filter_testdir | _filter_imgfmt

 new_len=$(get_proto_len "$EXT_MP" "$TEST_IMG")