[Qemu-block] [PATCH v3 04/25] block: Respect backing bs in bdrv_refresh_filename

[Max Reitz]

Basically, bdrv_refresh_filename() should respect all children of a
BlockDriverState. However, generally those children are driver-specific,
so this function cannot handle the general case. On the other hand,
there are only few drivers which use other children than @file and
@backing (that being vmdk, quorum, and blkverify).

Most block drivers only use @file and/or @backing (if they use any
children at all). Both can be implemented directly in
bdrv_refresh_filename.

The user overriding the file's filename is already handled, however, the
user overriding the backing file is not. If this is done, opening the
BDS with the plain filename of its file will not be correct, so we may
not set bs->exact_filename in that case.

iotest 051 contains test cases for overwriting the backing file, and so
its output changes with this patch applied (which I consider a good
thing).

Signed-off-by: Max Reitz <address@hidden>
---
 block.c                       | 12 +++++++++++-
 tests/qemu-iotests/051.out    |  8 ++++----
 tests/qemu-iotests/051.pc.out |  8 ++++----
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/block.c b/block.c
index 438201d..f7a287a 100644
--- a/block.c
+++ b/block.c
@@ -3999,6 +3999,7 @@ void bdrv_refresh_filename(BlockDriverState *bs)
 
         opts = qdict_new();
         has_open_options = append_open_options(opts, bs);
+        has_open_options |= bs->backing_overridden;
 
         /* If no specific options have been given for this BDS, the filename of
          * the underlying file should suffice for this one as well */
@@ -4010,13 +4011,22 @@ void bdrv_refresh_filename(BlockDriverState *bs)
          * file BDS. The full options QDict of that file BDS should somehow
          * contain a representation of the filename, therefore the following
          * suffices without querying the (exact_)filename of this BDS. */
-        if (bs->file->bs->full_open_options) {
+        if (bs->file->bs->full_open_options &&
+            (!bs->backing || bs->backing->bs->full_open_options))
+        {
             qdict_put_obj(opts, "driver",
                           QOBJECT(qstring_from_str(drv->format_name)));
             QINCREF(bs->file->bs->full_open_options);
             qdict_put_obj(opts, "file",
                           QOBJECT(bs->file->bs->full_open_options));
 
+            if (bs->backing) {
+                QINCREF(bs->backing->bs->full_open_options);
+                qdict_put(opts, "backing", bs->backing->bs->full_open_options);
+            } else if (bs->backing_overridden && !bs->backing) {
+                qdict_put(opts, "backing", qstring_new());
+            }
+
             bs->full_open_options = opts;
         } else {
             QDECREF(opts);
diff --git a/tests/qemu-iotests/051.out b/tests/qemu-iotests/051.out
index 42bf416..0d0b3b1 100644
--- a/tests/qemu-iotests/051.out
+++ b/tests/qemu-iotests/051.out
@@ -59,7 +59,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 Testing: -drive 
file=TEST_DIR/t.qcow2,driver=qcow2,backing.file.filename=TEST_DIR/t.qcow2.orig,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.orig"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback
     Backing file:     TEST_DIR/t.qcow2.orig (chain depth: 1)
@@ -148,7 +148,7 @@ QEMU_PROG: -drive driver=null-co,cache=invalid_value: 
invalid cache option
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=writeback,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
@@ -168,7 +168,7 @@ backing-file: TEST_DIR/t.qcow2.base (file, read-only)
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=writethrough,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writethrough
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
@@ -188,7 +188,7 @@ backing-file: TEST_DIR/t.qcow2.base (file, read-only)
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=unsafe,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback, ignore flushes
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
diff --git a/tests/qemu-iotests/051.pc.out b/tests/qemu-iotests/051.pc.out
index 603bb76..4b830bc 100644
--- a/tests/qemu-iotests/051.pc.out
+++ b/tests/qemu-iotests/051.pc.out
@@ -59,7 +59,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 Testing: -drive 
file=TEST_DIR/t.qcow2,driver=qcow2,backing.file.filename=TEST_DIR/t.qcow2.orig,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.orig"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback
     Backing file:     TEST_DIR/t.qcow2.orig (chain depth: 1)
@@ -242,7 +242,7 @@ QEMU_PROG: -drive driver=null-co,cache=invalid_value: 
invalid cache option
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=writeback,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
@@ -262,7 +262,7 @@ backing-file: TEST_DIR/t.qcow2.base (file, read-only)
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=writethrough,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writethrough
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
@@ -282,7 +282,7 @@ backing-file: TEST_DIR/t.qcow2.base (file, read-only)
 Testing: -drive 
file=TEST_DIR/t.qcow2,cache=unsafe,backing.file.filename=TEST_DIR/t.qcow2.base,backing.cache.no-flush=on,backing.node-name=backing,backing.file.node-name=backing-file,file.node-name=file,if=none,id=drive0
 -nodefaults
 QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) iininfinfoinfo 
info binfo 
blinfo bloinfo 
blocinfo block
-drive0 (NODE_NAME): TEST_DIR/t.qcow2 (qcow2)
+drive0 (NODE_NAME): json:{"backing": {"driver": "qcow2", "file": {"driver": 
"file", "filename": "TEST_DIR/t.qcow2.base"}}, "driver": "qcow2", "file": 
{"driver": "file", "filename": "TEST_DIR/t.qcow2"}} (qcow2)
     Removable device: not locked, tray closed
     Cache mode:       writeback, ignore flushes
     Backing file:     TEST_DIR/t.qcow2.base (chain depth: 1)
-- 
2.10.2