[Qemu-devel] [PATCH 0/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Qemu-devel] [PATCH 0/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Kevin Wolf]

Currently you have to decide whether you want to use -snapshot/snapshot=on or
driver-specific options, they don't go together. This series removes this
limitation.

Kevin Wolf (2):
  block: Enable BDRV_O_SNAPSHOT with driver-specific options
  qemu-iotests: Test snapshot mode

 block.c                    | 49 ++++++++++++++++++++---------------------
 tests/qemu-iotests/051     | 17 +++++++++++++++
 tests/qemu-iotests/051.out | 54 +++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 89 insertions(+), 31 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH 1/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Kevin Wolf]

In the case of snapshot=on, don't rely on the backing file path in the
temporary image any more, but override the backing file with the given
set of options. This way, block drivers that don't use a file name can
be accessed with snapshot=on, for example:

    -drive file.driver=nbd,file.host=localhost,snapshot=on

Which becomes internally something like:

    file.filename=/tmp/vl.AWQZCu,backing.file.driver=nbd,backing.file.host=localhost

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 49 +++++++++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 26 deletions(-)

diff --git a/block.c b/block.c
index 382ea71..51fcb59 100644
--- a/block.c
+++ b/block.c
@@ -1052,21 +1052,15 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
         int64_t total_size;
         BlockDriver *bdrv_qcow2;
         QEMUOptionParameter *create_options;
-        char backing_filename[PATH_MAX];
-
-        if (qdict_size(options) != 0) {
-            error_setg(errp, "Can't use snapshot=on with driver-specific options");
-            ret = -EINVAL;
-            goto fail;
-        }
-        assert(filename != NULL);
+        QDict *snapshot_options;
 
         /* if snapshot, we create a temporary backing file and open it
            instead of opening 'filename' directly */
 
-        /* if there is a backing file, use it */
+        /* Get the required size from the image */
         bs1 = bdrv_new("");
-        ret = bdrv_open(bs1, filename, NULL, 0, drv, &local_err);
+        QINCREF(options);
+        ret = bdrv_open(bs1, filename, options, 0, drv, &local_err);
         if (ret < 0) {
             bdrv_unref(bs1);
             goto fail;
@@ -1075,33 +1069,18 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
 
         bdrv_unref(bs1);
 
+        /* Create the temporary image */
         ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
         if (ret < 0) {
             error_setg_errno(errp, -ret, "Could not get temporary filename");
             goto fail;
         }
 
-        /* Real path is meaningless for protocols */
-        if (path_has_protocol(filename)) {
-            snprintf(backing_filename, sizeof(backing_filename),
-                     "%s", filename);
-        } else if (!realpath(filename, backing_filename)) {
-            ret = -errno;
-            error_setg_errno(errp, errno, "Could not resolve path '%s'", filename);
-            goto fail;
-        }
-
         bdrv_qcow2 = bdrv_find_format("qcow2");
         create_options = parse_option_parameters("", bdrv_qcow2->create_options,
                                                  NULL);
 
         set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size);
-        set_option_parameter(create_options, BLOCK_OPT_BACKING_FILE,
-                             backing_filename);
-        if (drv) {
-            set_option_parameter(create_options, BLOCK_OPT_BACKING_FMT,
-                drv->format_name);
-        }
 
         ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err);
         free_option_parameters(create_options);
@@ -1114,6 +1093,24 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
             goto fail;
         }
 
+        /* Prepare a new options QDict for the temporary file, where user
+         * options refer to the backing file */
+        if (!options) {
+            options = qdict_new();
+        }
+        if (filename) {
+            qdict_put(options, "file.filename", qstring_from_str(filename));
+        }
+        if (drv) {
+            qdict_put(options, "driver", qstring_from_str(drv->format_name));
+        }
+
+        snapshot_options = qdict_new();
+        qdict_put(snapshot_options, "backing", options);
+        qdict_flatten(snapshot_options);
+
+        options = snapshot_options;
+
         filename = tmp_filename;
         drv = bdrv_qcow2;
         bs->is_temporary = 1;
-- 
1.8.1.4

[Qemu-devel] [PATCH 2/2] qemu-iotests: Test snapshot mode

[Kevin Wolf]

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/051     | 17 +++++++++++++++
 tests/qemu-iotests/051.out | 54 +++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/tests/qemu-iotests/051 b/tests/qemu-iotests/051
index 3a75bda..b23d91b 100755
--- a/tests/qemu-iotests/051
+++ b/tests/qemu-iotests/051
@@ -183,6 +183,23 @@ run_qemu -hda foo:bar
 run_qemu -drive file=foo:bar
 run_qemu -drive file.filename=foo:bar
 
+echo
+echo === Snapshot mode ===
+echo
+
+$QEMU_IO -c "write -P 0x11 0 4k" "$TEST_IMG" | _filter_qemu_io
+
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG" -snapshot | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG",snapshot=on | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file.filename="$TEST_IMG",driver=qcow2,snapshot=on | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file.filename="$TEST_IMG",driver=qcow2 -snapshot | _filter_qemu_io
+
+$QEMU_IO -c "read -P 0x11 0 4k" "$TEST_IMG" | _filter_qemu_io
+
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG",snapshot=off | _filter_qemu_io
+
+$QEMU_IO -c "read -P 0x22 0 4k" "$TEST_IMG" | _filter_qemu_io
+
 # success, all done
 echo "*** done"
 rm -f $seq.full
diff --git a/tests/qemu-iotests/051.out b/tests/qemu-iotests/051.out
index 8769c8e..ddef87c 100644
--- a/tests/qemu-iotests/051.out
+++ b/tests/qemu-iotests/051.out
@@ -29,11 +29,11 @@ QEMU_PROG: -drive file=TEST_DIR/t.qcow2,driver=foo: could not open disk image TE
 === Overriding backing file ===
 
 Testing: -drive file=TEST_DIR/t.qcow2,driver=qcow2,backing.file.filename=TEST_DIR/t.qcow2.orig -nodefaults
-QEMU X.Y.Z monitor - type 'help' for more information
-(qemu) i^[[K^[[Din^[[K^[[D^[[Dinf^[[K^[[D^[[D^[[Dinfo^[[K^[[D^[[D^[[D^[[Dinfo ^[[K^[[D^[[D^[[D^[[D^[[Dinfo b^[[K^[[D^[[D^[[D^[[D^[[D^[[Dinfo bl^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo blo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo bloc^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block^[[K
-ide0-hd0: TEST_DIR/t.qcow2 (qcow2)
-    Backing file:     TEST_DIR/t.qcow2.orig (chain depth: 1)
-(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) i^[[K^[[Din^[[K^[[D^[[Dinf^[[K^[[D^[[D^[[Dinfo^[[K^[[D^[[D^[[D^[[Dinfo ^[[K^[[D^[[D^[[D^[[D^[[Dinfo b^[[K^[[D^[[D^[[D^[[D^[[D^[[Dinfo bl^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo blo^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo bloc^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dinfo block^[[K
+ide0-hd0: TEST_DIR/t.qcow2 (qcow2)
+    Backing file:     TEST_DIR/t.qcow2.orig (chain depth: 1)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
 
 
 === Enable and disable lazy refcounting on the command line, plus some invalid values ===
@@ -237,4 +237,48 @@ QEMU_PROG: -drive file=foo:bar: could not open disk image foo:bar: Unknown proto
 Testing: -drive file.filename=foo:bar
 QEMU_PROG: -drive file.filename=foo:bar: could not open disk image ide0-hd0: Could not open 'foo:bar': No such file or directory
 
+
+=== Snapshot mode ===
+
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Testing: -drive file=TEST_DIR/t.qcow2 -snapshot
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q^[[K^[[Dqe^[[K^[[D^[[Dqem^[[K^[[D^[[D^[[Dqemu^[[K^[[D^[[D^[[D^[[Dqemu-^[[K^[[D^[[D^[[D^[[D^[[Dqemu-i^[[K^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io i^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io id^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-h^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wr^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wri^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D!
 ^[[D^[[Dqemu-io ide0-hd0 "writ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x2^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w!
 rite -P 0x22^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[
[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k"^[[K
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+
+Testing: -drive file=TEST_DIR/t.qcow2,snapshot=on
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q^[[K^[[Dqe^[[K^[[D^[[Dqem^[[K^[[D^[[D^[[Dqemu^[[K^[[D^[[D^[[D^[[Dqemu-^[[K^[[D^[[D^[[D^[[D^[[Dqemu-i^[[K^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io i^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io id^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-h^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wr^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wri^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D!
 ^[[D^[[Dqemu-io ide0-hd0 "writ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x2^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w!
 rite -P 0x22^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[
[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k"^[[K
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+
+Testing: -drive file.filename=TEST_DIR/t.qcow2,driver=qcow2,snapshot=on
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q^[[K^[[Dqe^[[K^[[D^[[Dqem^[[K^[[D^[[D^[[Dqemu^[[K^[[D^[[D^[[D^[[Dqemu-^[[K^[[D^[[D^[[D^[[D^[[Dqemu-i^[[K^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io i^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io id^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-h^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wr^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wri^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D!
 ^[[D^[[Dqemu-io ide0-hd0 "writ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x2^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w!
 rite -P 0x22^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[
[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k"^[[K
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+
+Testing: -drive file.filename=TEST_DIR/t.qcow2,driver=qcow2 -snapshot
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q^[[K^[[Dqe^[[K^[[D^[[Dqem^[[K^[[D^[[D^[[Dqemu^[[K^[[D^[[D^[[D^[[Dqemu-^[[K^[[D^[[D^[[D^[[D^[[Dqemu-i^[[K^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io i^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io id^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-h^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wr^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wri^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D!
 ^[[D^[[Dqemu-io ide0-hd0 "writ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x2^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w!
 rite -P 0x22^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[
[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "write -P 0x22 0 4k"^[[K
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+
+read 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Testing: -drive file=TEST_DIR/t.qcow2,snapshot=off
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) q^[[K^[[Dqe^[[K^[[D^[[Dqem^[[K^[[D^[[D^[[Dqemu^[[K^[[D^[[D^[[D^[[Dqemu-^[[K^[[D^[[D^[[D^[[D^[[Dqemu-i^[[K^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io i^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io id^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-h^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 ^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "w^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wr^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[Dqemu-io ide0-hd0 "wri^[[K^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D^[[D!
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+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) q^[[K^[[Dqu^[[K^[[D^[[Dqui^[[K^[[D^[[D^[[Dquit^[[K
+
+read 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 *** done
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH 1/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Eric Blake]

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On 11/19/2013 08:37 AM, Kevin Wolf wrote:
> In the case of snapshot=on, don't rely on the backing file path in the
> temporary image any more, but override the backing file with the given
> set of options. This way, block drivers that don't use a file name can
> be accessed with snapshot=on, for example:
> 
>     -drive file.driver=nbd,file.host=localhost,snapshot=on
> 
> Which becomes internally something like:
> 
>     file.filename=/tmp/vl.AWQZCu,backing.file.driver=nbd,backing.file.host=localhost

[libvirt isn't using snapshot=on, but that doesn't affect the utility of
this patch]

> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 49 +++++++++++++++++++++++--------------------------
>  1 file changed, 23 insertions(+), 26 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH 2/2] qemu-iotests: Test snapshot mode

[Eric Blake]

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On 11/19/2013 08:37 AM, Kevin Wolf wrote:
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  tests/qemu-iotests/051     | 17 +++++++++++++++
>  tests/qemu-iotests/051.out | 54 +++++++++++++++++++++++++++++++++++++++++-----
>  2 files changed, 66 insertions(+), 5 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH 1/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Stefan Hajnoczi]

On Tue, Nov 19, 2013 at 04:37:27PM +0100, Kevin Wolf wrote:
> @@ -1114,6 +1093,24 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
>              goto fail;
>          }
>  
> +        /* Prepare a new options QDict for the temporary file, where user
> +         * options refer to the backing file */
> +        if (!options) {
> +            options = qdict_new();
> +        }

You can drop this because options is never NULL:

  options = qdict_clone_shallow(options);

  /* For snapshot=on, create a temporary qcow2 overlay */
  if (flags & BDRV_O_SNAPSHOT) {
      ...

> +        if (filename) {
> +            qdict_put(options, "file.filename", qstring_from_str(filename));
> +        }
> +        if (drv) {
> +            qdict_put(options, "driver", qstring_from_str(drv->format_name));
> +        }
> +
> +        snapshot_options = qdict_new();
> +        qdict_put(snapshot_options, "backing", options);
> +        qdict_flatten(snapshot_options);
> +
> +        options = snapshot_options;

One thing I'm not sure about after these operations have been performed:

  bs->options = options;
  ...
  if (flags & BDRV_O_SNAPSHOT) {
      ...

So bs->options does not reflect what we ended up with in the
BDRV_O_SNAPSHOT case.

But git grep -- '->options' shows no users of this field.  Therefore it
won't cause a problem yet.  But can you explain what's going on here?
Either we should keep bs->options up-to-date or we should drop the
field.

Stefan

Re: [Qemu-devel] [PATCH 1/2] block: Enable BDRV_O_SNAPSHOT with driver-specific options

[Kevin Wolf]

Am 21.11.2013 um 15:33 hat Stefan Hajnoczi geschrieben:
> On Tue, Nov 19, 2013 at 04:37:27PM +0100, Kevin Wolf wrote:
> > @@ -1114,6 +1093,24 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
> >              goto fail;
> >          }
> >  
> > +        /* Prepare a new options QDict for the temporary file, where user
> > +         * options refer to the backing file */
> > +        if (!options) {
> > +            options = qdict_new();
> > +        }
> 
> You can drop this because options is never NULL:
> 
>   options = qdict_clone_shallow(options);
> 
>   /* For snapshot=on, create a temporary qcow2 overlay */
>   if (flags & BDRV_O_SNAPSHOT) {
>       ...

You're right, I'll remove it in v2.

> > +        if (filename) {
> > +            qdict_put(options, "file.filename", qstring_from_str(filename));
> > +        }
> > +        if (drv) {
> > +            qdict_put(options, "driver", qstring_from_str(drv->format_name));
> > +        }
> > +
> > +        snapshot_options = qdict_new();
> > +        qdict_put(snapshot_options, "backing", options);
> > +        qdict_flatten(snapshot_options);
> > +
> > +        options = snapshot_options;
> 
> One thing I'm not sure about after these operations have been performed:
> 
>   bs->options = options;
>   ...
>   if (flags & BDRV_O_SNAPSHOT) {
>       ...
> 
> So bs->options does not reflect what we ended up with in the
> BDRV_O_SNAPSHOT case.
> 
> But git grep -- '->options' shows no users of this field.  Therefore it
> won't cause a problem yet.  But can you explain what's going on here?
> Either we should keep bs->options up-to-date or we should drop the
> field.

I think bs->options was meant to be used in cases where we reopen a BDS.
If it's currently unused, I guess this means we have some bugs. :-)

Should bs->options be the original options passed by the user or the
ones modified by BDRV_O_SNAPSHOT? I'm not completely sure, but I think
the modified ones make more sense; it would also make it easier to move
the whole BDRV_O_SNAPSHOT logic out to drive_init (which I plan to do in
a next step).

Kevin