block: Add backend_defaults property

backend_defaults property allow users to control if default block
properties should be decided with backend information.

If it is off, any backend information will be discarded, which is
suitable if you plan to perform live migration to a different disk backend.

If it is on, a block device may utilize backend information more
aggressively.

By default, it is auto, which uses backend information for block
sizes and ignores the others, which is consistent with the older
versions.

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Message-id: 20210705130458.97642-2-akihiko.odaki@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/qemu-iotests/172.out b/tests/qemu-iotests/172.out
index d53f61d0de..4cf4d536b4 100644
--- a/tests/qemu-iotests/172.out
+++ b/tests/qemu-iotests/172.out
@@ -21,6 +21,7 @@ Testing:
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -48,6 +49,7 @@ Testing: -fda TEST_DIR/t.qcow2
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -85,6 +87,7 @@ Testing: -fdb TEST_DIR/t.qcow2
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -96,6 +99,7 @@ Testing: -fdb TEST_DIR/t.qcow2
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -137,6 +141,7 @@ Testing: -fda TEST_DIR/t.qcow2 -fdb TEST_DIR/t.qcow2.2
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -148,6 +153,7 @@ Testing: -fda TEST_DIR/t.qcow2 -fdb TEST_DIR/t.qcow2.2
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -190,6 +196,7 @@ Testing: -fdb
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -201,6 +208,7 @@ Testing: -fdb
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -228,6 +236,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -265,6 +274,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2,index=1
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -276,6 +286,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2,index=1
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -317,6 +328,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=floppy,file=TEST_DIR/t
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -328,6 +340,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=floppy,file=TEST_DIR/t
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -373,6 +386,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -410,6 +424,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,unit=1
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -447,6 +462,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qco
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -458,6 +474,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qco
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -509,6 +526,7 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -520,6 +538,7 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -562,6 +581,7 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -573,6 +593,7 @@ Testing: -fda TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -615,6 +636,7 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -626,6 +648,7 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -668,6 +691,7 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -679,6 +703,7 @@ Testing: -fdb TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.qcow2.2 -device fl
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "floppy1"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -730,6 +755,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -741,6 +767,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -783,6 +810,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
               dev: floppy, id ""
                 unit = 1 (0x1)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -794,6 +822,7 @@ Testing: -drive if=floppy,file=TEST_DIR/t.qcow2 -drive if=none,file=TEST_DIR/t.q
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "floppy0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -842,6 +871,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -global floppy.drive=none0 -device
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -909,6 +939,7 @@ Testing: -device floppy
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = ""
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -933,6 +964,7 @@ Testing: -device floppy,drive-type=120
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = ""
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -957,6 +989,7 @@ Testing: -device floppy,drive-type=144
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = ""
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -981,6 +1014,7 @@ Testing: -device floppy,drive-type=288
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = ""
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -1008,6 +1042,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,drive-t
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -1045,6 +1080,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,drive-t
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -1085,6 +1121,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,logical
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)
@@ -1122,6 +1159,7 @@ Testing: -drive if=none,file=TEST_DIR/t.qcow2 -device floppy,drive=none0,physica
               dev: floppy, id ""
                 unit = 0 (0x0)
                 drive = "none0"
+                backend_defaults = "auto"
                 logical_block_size = 512 (512 B)
                 physical_block_size = 512 (512 B)
                 min_io_size = 0 (0 B)