| Message ID | 20171110221329.24176-3-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | block: Handle null backing link | expand |
On 11/10/2017 04:13 PM, Max Reitz wrote: > Instead of converting all "backing": null instances into "backing": "", > handle a null value directly in bdrv_open_inherit(). > > This enables explicitly null backing links for json:{} filenames. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block.c | 2 +- > blockdev.c | 14 -------------- > tests/qemu-iotests/089 | 20 ++++++++++++++++++++ > tests/qemu-iotests/089.out | 8 ++++++++ > 4 files changed, 29 insertions(+), 15 deletions(-) > > @@ -3899,19 +3898,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) > > qdict_flatten(qdict); > > - /* > - * Rewrite "backing": null to "backing": "" > - * TODO Rewrite "" to null instead, and perhaps not even here > - */ Nice that the TODO told you what to do :) Reviewed-by: Eric Blake <eblake@redhat.com>
On 2017-11-10 23:22, Eric Blake wrote: > On 11/10/2017 04:13 PM, Max Reitz wrote: >> Instead of converting all "backing": null instances into "backing": "", >> handle a null value directly in bdrv_open_inherit(). >> >> This enables explicitly null backing links for json:{} filenames. >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> --- >> block.c | 2 +- >> blockdev.c | 14 -------------- >> tests/qemu-iotests/089 | 20 ++++++++++++++++++++ >> tests/qemu-iotests/089.out | 8 ++++++++ >> 4 files changed, 29 insertions(+), 15 deletions(-) >> > >> @@ -3899,19 +3898,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) >> >> qdict_flatten(qdict); >> >> - /* >> - * Rewrite "backing": null to "backing": "" >> - * TODO Rewrite "" to null instead, and perhaps not even here >> - */ > > Nice that the TODO told you what to do :) Well, not really, because I disagree that it needs to be rewritten at all. I think we just need to deprecate and later disallow "backing": "", which would absolve us from all of the rewriting trouble. This code was added here because Markus needed to allow "backing": null in a hurry (as far as I remember), so he added it centrally here instead of checking how many places there are that evaluate "backing": "". I should maybe have said that patch 3 is more of an RFC. I'm not sure whether other people agree that "backing": "" should be deprecated -- and if not, we would have to rewrite it still. Max
On Fri 10 Nov 2017 11:13:28 PM CET, Max Reitz wrote: > Instead of converting all "backing": null instances into "backing": "", > handle a null value directly in bdrv_open_inherit(). > > This enables explicitly null backing links for json:{} filenames. > > Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Berto
Max Reitz <mreitz@redhat.com> writes: > Instead of converting all "backing": null instances into "backing": "", > handle a null value directly in bdrv_open_inherit(). > > This enables explicitly null backing links for json:{} filenames. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block.c | 2 +- > blockdev.c | 14 -------------- > tests/qemu-iotests/089 | 20 ++++++++++++++++++++ > tests/qemu-iotests/089.out | 8 ++++++++ > 4 files changed, 29 insertions(+), 15 deletions(-) > > diff --git a/block.c b/block.c > index 85427df577..bc92ddd5a0 100644 > --- a/block.c > +++ b/block.c > @@ -2558,7 +2558,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, > > /* See cautionary note on accessing @options above */ > backing = qdict_get_try_str(options, "backing"); > - if (backing && *backing == '\0') { > + if (qdict_is_qnull(options, "backing") || (backing && *backing == '\0')) { > flags |= BDRV_O_NO_BACKING; > qdict_del(options, "backing"); > } Consider a comment pointing out "" is deprecated. See also my reply to PATCH 1/3. > diff --git a/blockdev.c b/blockdev.c > index 56a6b24a0b..99ef618b39 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -3885,7 +3885,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) > QObject *obj; > Visitor *v = qobject_output_visitor_new(&obj); > QDict *qdict; > - const QDictEntry *ent; > Error *local_err = NULL; > > visit_type_BlockdevOptions(v, NULL, &options, &local_err); > @@ -3899,19 +3898,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) > > qdict_flatten(qdict); > > - /* > - * Rewrite "backing": null to "backing": "" > - * TODO Rewrite "" to null instead, and perhaps not even here > - */ > - for (ent = qdict_first(qdict); ent; ent = qdict_next(qdict, ent)) { > - char *dot = strrchr(ent->key, '.'); > - > - if (!strcmp(dot ? dot + 1 : ent->key, "backing") > - && qobject_type(ent->value) == QTYPE_QNULL) { > - qdict_put(qdict, ent->key, qstring_new()); > - } > - } > - > if (!qdict_get_try_str(qdict, "node-name")) { > error_setg(errp, "'node-name' must be specified for the root node"); > goto fail; > diff --git a/tests/qemu-iotests/089 b/tests/qemu-iotests/089 > index 9bfe2307b3..832eac1248 100755 > --- a/tests/qemu-iotests/089 > +++ b/tests/qemu-iotests/089 > @@ -82,6 +82,26 @@ $QEMU_IO_PROG --cache $CACHEMODE \ > $QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io > > > +echo > +echo "=== Testing correct handling of 'backing':null ===" > +echo > + > +_make_test_img -b "$TEST_IMG.base" $IMG_SIZE > + > +# This should read 42 > +$QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io > + > +# This should read 0 > +$QEMU_IO -c 'read -P 0 0 512' "json:{\ > + 'driver': '$IMGFMT', > + 'file': { > + 'driver': 'file', > + 'filename': '$TEST_IMG' > + }, > + 'backing': null > +}" | _filter_qemu_io > + > + > # Taken from test 071 > echo > echo "=== Testing blkdebug ===" > diff --git a/tests/qemu-iotests/089.out b/tests/qemu-iotests/089.out > index 18f5fdda7a..607a9c6d9c 100644 > --- a/tests/qemu-iotests/089.out > +++ b/tests/qemu-iotests/089.out > @@ -19,6 +19,14 @@ Pattern verification failed at offset 0, 512 bytes > read 512/512 bytes at offset 0 > 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > > +=== Testing correct handling of 'backing':null === > + > +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base > +read 512/512 bytes at offset 0 > +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > +read 512/512 bytes at offset 0 > +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) > + > === Testing blkdebug === > > Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 Reviewed-by: Markus Armbruster <armbru@redhat.com>
On 2017-11-14 16:17, Markus Armbruster wrote: > Max Reitz <mreitz@redhat.com> writes: > >> Instead of converting all "backing": null instances into "backing": "", >> handle a null value directly in bdrv_open_inherit(). >> >> This enables explicitly null backing links for json:{} filenames. >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> --- >> block.c | 2 +- >> blockdev.c | 14 -------------- >> tests/qemu-iotests/089 | 20 ++++++++++++++++++++ >> tests/qemu-iotests/089.out | 8 ++++++++ >> 4 files changed, 29 insertions(+), 15 deletions(-) >> >> diff --git a/block.c b/block.c >> index 85427df577..bc92ddd5a0 100644 >> --- a/block.c >> +++ b/block.c >> @@ -2558,7 +2558,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, >> >> /* See cautionary note on accessing @options above */ >> backing = qdict_get_try_str(options, "backing"); >> - if (backing && *backing == '\0') { >> + if (qdict_is_qnull(options, "backing") || (backing && *backing == '\0')) { >> flags |= BDRV_O_NO_BACKING; >> qdict_del(options, "backing"); >> } > > Consider a comment pointing out "" is deprecated. Would not really be necessary after patch 3, but let's see how well patch 3 is received. :-) (And in any case, a comment certainly won't hurt.) Max > See also my reply to PATCH 1/3. > >> diff --git a/blockdev.c b/blockdev.c >> index 56a6b24a0b..99ef618b39 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -3885,7 +3885,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) >> QObject *obj; >> Visitor *v = qobject_output_visitor_new(&obj); >> QDict *qdict; >> - const QDictEntry *ent; >> Error *local_err = NULL; >> >> visit_type_BlockdevOptions(v, NULL, &options, &local_err); >> @@ -3899,19 +3898,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) >> >> qdict_flatten(qdict); >> >> - /* >> - * Rewrite "backing": null to "backing": "" >> - * TODO Rewrite "" to null instead, and perhaps not even here >> - */ >> - for (ent = qdict_first(qdict); ent; ent = qdict_next(qdict, ent)) { >> - char *dot = strrchr(ent->key, '.'); >> - >> - if (!strcmp(dot ? dot + 1 : ent->key, "backing") >> - && qobject_type(ent->value) == QTYPE_QNULL) { >> - qdict_put(qdict, ent->key, qstring_new()); >> - } >> - } >> - >> if (!qdict_get_try_str(qdict, "node-name")) { >> error_setg(errp, "'node-name' must be specified for the root node"); >> goto fail; >> diff --git a/tests/qemu-iotests/089 b/tests/qemu-iotests/089 >> index 9bfe2307b3..832eac1248 100755 >> --- a/tests/qemu-iotests/089 >> +++ b/tests/qemu-iotests/089 >> @@ -82,6 +82,26 @@ $QEMU_IO_PROG --cache $CACHEMODE \ >> $QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io >> >> >> +echo >> +echo "=== Testing correct handling of 'backing':null ===" >> +echo >> + >> +_make_test_img -b "$TEST_IMG.base" $IMG_SIZE >> + >> +# This should read 42 >> +$QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io >> + >> +# This should read 0 >> +$QEMU_IO -c 'read -P 0 0 512' "json:{\ >> + 'driver': '$IMGFMT', >> + 'file': { >> + 'driver': 'file', >> + 'filename': '$TEST_IMG' >> + }, >> + 'backing': null >> +}" | _filter_qemu_io >> + >> + >> # Taken from test 071 >> echo >> echo "=== Testing blkdebug ===" >> diff --git a/tests/qemu-iotests/089.out b/tests/qemu-iotests/089.out >> index 18f5fdda7a..607a9c6d9c 100644 >> --- a/tests/qemu-iotests/089.out >> +++ b/tests/qemu-iotests/089.out >> @@ -19,6 +19,14 @@ Pattern verification failed at offset 0, 512 bytes >> read 512/512 bytes at offset 0 >> 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >> >> +=== Testing correct handling of 'backing':null === >> + >> +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base >> +read 512/512 bytes at offset 0 >> +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >> +read 512/512 bytes at offset 0 >> +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) >> + >> === Testing blkdebug === >> >> Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 > > Reviewed-by: Markus Armbruster <armbru@redhat.com> >
diff --git a/block.c b/block.c index 85427df577..bc92ddd5a0 100644 --- a/block.c +++ b/block.c @@ -2558,7 +2558,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, /* See cautionary note on accessing @options above */ backing = qdict_get_try_str(options, "backing"); - if (backing && *backing == '\0') { + if (qdict_is_qnull(options, "backing") || (backing && *backing == '\0')) { flags |= BDRV_O_NO_BACKING; qdict_del(options, "backing"); } diff --git a/blockdev.c b/blockdev.c index 56a6b24a0b..99ef618b39 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3885,7 +3885,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) QObject *obj; Visitor *v = qobject_output_visitor_new(&obj); QDict *qdict; - const QDictEntry *ent; Error *local_err = NULL; visit_type_BlockdevOptions(v, NULL, &options, &local_err); @@ -3899,19 +3898,6 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp) qdict_flatten(qdict); - /* - * Rewrite "backing": null to "backing": "" - * TODO Rewrite "" to null instead, and perhaps not even here - */ - for (ent = qdict_first(qdict); ent; ent = qdict_next(qdict, ent)) { - char *dot = strrchr(ent->key, '.'); - - if (!strcmp(dot ? dot + 1 : ent->key, "backing") - && qobject_type(ent->value) == QTYPE_QNULL) { - qdict_put(qdict, ent->key, qstring_new()); - } - } - if (!qdict_get_try_str(qdict, "node-name")) { error_setg(errp, "'node-name' must be specified for the root node"); goto fail; diff --git a/tests/qemu-iotests/089 b/tests/qemu-iotests/089 index 9bfe2307b3..832eac1248 100755 --- a/tests/qemu-iotests/089 +++ b/tests/qemu-iotests/089 @@ -82,6 +82,26 @@ $QEMU_IO_PROG --cache $CACHEMODE \ $QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io +echo +echo "=== Testing correct handling of 'backing':null ===" +echo + +_make_test_img -b "$TEST_IMG.base" $IMG_SIZE + +# This should read 42 +$QEMU_IO -c 'read -P 42 0 512' "$TEST_IMG" | _filter_qemu_io + +# This should read 0 +$QEMU_IO -c 'read -P 0 0 512' "json:{\ + 'driver': '$IMGFMT', + 'file': { + 'driver': 'file', + 'filename': '$TEST_IMG' + }, + 'backing': null +}" | _filter_qemu_io + + # Taken from test 071 echo echo "=== Testing blkdebug ===" diff --git a/tests/qemu-iotests/089.out b/tests/qemu-iotests/089.out index 18f5fdda7a..607a9c6d9c 100644 --- a/tests/qemu-iotests/089.out +++ b/tests/qemu-iotests/089.out @@ -19,6 +19,14 @@ Pattern verification failed at offset 0, 512 bytes read 512/512 bytes at offset 0 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +=== Testing correct handling of 'backing':null === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base +read 512/512 bytes at offset 0 +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +read 512/512 bytes at offset 0 +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + === Testing blkdebug === Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
Instead of converting all "backing": null instances into "backing": "", handle a null value directly in bdrv_open_inherit(). This enables explicitly null backing links for json:{} filenames. Signed-off-by: Max Reitz <mreitz@redhat.com> --- block.c | 2 +- blockdev.c | 14 -------------- tests/qemu-iotests/089 | 20 ++++++++++++++++++++ tests/qemu-iotests/089.out | 8 ++++++++ 4 files changed, 29 insertions(+), 15 deletions(-)