[Qemu-devel] [PATCH v2 0/2] block: Fix permission during reopen

[Qemu-devel] [PATCH v2 0/2] block: Fix permission during reopen

[Fam Zheng]

v2: Use update_flags_from_options. [Kevin]

We write open the whole backing chain during reopen. It is not necessary and
will cause image locking problems if the backing image is shared.

Fam Zheng (2):
  block: Fix flags in reopen queue
  iotests: Add regression test for commit base locking

 block.c                    | 7 +++++++
 tests/qemu-iotests/153     | 8 ++++++++
 tests/qemu-iotests/153.out | 4 ++++
 3 files changed, 19 insertions(+)

-- 
2.14.3

[Qemu-devel] [PATCH v2 1/2] block: Fix flags in reopen queue

[Fam Zheng]

Reopen flags are not synchronized according to the
bdrv_reopen_queue_child precedence until bdrv_reopen_prepare. It is a
bit too late: we already check the consistency in bdrv_check_perm before
that.

This fixes the bug that when bdrv_reopen a RO node as RW, the flags for
backing child are wrong. Before, we could recurse with flags.rw=1; now,
role->inherit_options + update_flags_from_options will make sure to
clear the bit when necessary.  Note that this will not clear an
explicitly set bit, as in the case of parallel block jobs (e.g.
test_stream_parallel in 030), because the explicit options include
'read-only=false' (for an intermediate node used by a different job).

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/block.c b/block.c
index 75a9fd49de..a121d2ebcc 100644
--- a/block.c
+++ b/block.c
@@ -2883,8 +2883,15 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
 
     /* Inherit from parent node */
     if (parent_options) {
+        QemuOpts *opts;
+        QDict *options_copy;
         assert(!flags);
         role->inherit_options(&flags, options, parent_flags, parent_options);
+        options_copy = qdict_clone_shallow(options);
+        opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
+        qemu_opts_absorb_qdict(opts, options_copy, NULL);
+        update_flags_from_options(&flags, opts);
+        qemu_opts_del(opts);
     }
 
     /* Old values are used for options that aren't set yet */
-- 
2.14.3

Re: [Qemu-devel] [PATCH v2 1/2] block: Fix flags in reopen queue

[Max Reitz]

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On 2018-03-13 12:58, Fam Zheng wrote:
> Reopen flags are not synchronized according to the
> bdrv_reopen_queue_child precedence until bdrv_reopen_prepare. It is a
> bit too late: we already check the consistency in bdrv_check_perm before
> that.
> 
> This fixes the bug that when bdrv_reopen a RO node as RW, the flags for
> backing child are wrong. Before, we could recurse with flags.rw=1; now,
> role->inherit_options + update_flags_from_options will make sure to
> clear the bit when necessary.  Note that this will not clear an
> explicitly set bit, as in the case of parallel block jobs (e.g.
> test_stream_parallel in 030), because the explicit options include
> 'read-only=false' (for an intermediate node used by a different job).
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block.c | 7 +++++++
>  1 file changed, 7 insertions(+)

Reviewed-by: Max Reitz <mreitz@redhat.com>


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[Qemu-devel] [PATCH v2 2/2] iotests: Add regression test for commit base locking

[Fam Zheng]

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 tests/qemu-iotests/153     | 8 ++++++++
 tests/qemu-iotests/153.out | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/tests/qemu-iotests/153 b/tests/qemu-iotests/153
index adfd02695b..a7875e6899 100755
--- a/tests/qemu-iotests/153
+++ b/tests/qemu-iotests/153
@@ -178,6 +178,14 @@ rm -f "${TEST_IMG}.lnk" &>/dev/null
 ln -s ${TEST_IMG} "${TEST_IMG}.lnk" || echo "Failed to create link"
 _run_qemu_with_images "${TEST_IMG}.lnk" "${TEST_IMG}"
 
+echo
+echo "== Active commit to intermediate layer should work when base in use =="
+_launch_qemu -drive format=$IMGFMT,file="${TEST_IMG}.a",id=drive0 \
+             -device virtio-blk,drive=drive0
+_run_cmd $QEMU_IMG commit -b "${TEST_IMG}.b" "${TEST_IMG}.c"
+
+_cleanup_qemu
+
 _launch_qemu
 
 _send_qemu_cmd $QEMU_HANDLE \
diff --git a/tests/qemu-iotests/153.out b/tests/qemu-iotests/153.out
index 34309cfb20..28f8250dd2 100644
--- a/tests/qemu-iotests/153.out
+++ b/tests/qemu-iotests/153.out
@@ -372,6 +372,10 @@ Is another process using the image?
 == Symbolic link ==
 QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2: Failed to get "write" lock
 Is another process using the image?
+
+== Active commit to intermediate layer should work when base in use ==
+
+_qemu_img_wrapper commit -b TEST_DIR/t.qcow2.b TEST_DIR/t.qcow2.c
 {"return": {}}
 Adding drive
 
-- 
2.14.3

Re: [Qemu-devel] [PATCH v2 2/2] iotests: Add regression test for commit base locking

[Max Reitz]

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On 2018-03-13 12:58, Fam Zheng wrote:
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  tests/qemu-iotests/153     | 8 ++++++++
>  tests/qemu-iotests/153.out | 4 ++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/tests/qemu-iotests/153 b/tests/qemu-iotests/153
> index adfd02695b..a7875e6899 100755
> --- a/tests/qemu-iotests/153
> +++ b/tests/qemu-iotests/153
> @@ -178,6 +178,14 @@ rm -f "${TEST_IMG}.lnk" &>/dev/null
>  ln -s ${TEST_IMG} "${TEST_IMG}.lnk" || echo "Failed to create link"
>  _run_qemu_with_images "${TEST_IMG}.lnk" "${TEST_IMG}"
>  
> +echo
> +echo "== Active commit to intermediate layer should work when base in use =="
> +_launch_qemu -drive format=$IMGFMT,file="${TEST_IMG}.a",id=drive0 \
> +             -device virtio-blk,drive=drive0
> +_run_cmd $QEMU_IMG commit -b "${TEST_IMG}.b" "${TEST_IMG}.c"
> +
> +_cleanup_qemu
> +
>  _launch_qemu
>  
>  _send_qemu_cmd $QEMU_HANDLE \
> diff --git a/tests/qemu-iotests/153.out b/tests/qemu-iotests/153.out
> index 34309cfb20..28f8250dd2 100644
> --- a/tests/qemu-iotests/153.out
> +++ b/tests/qemu-iotests/153.out
> @@ -372,6 +372,10 @@ Is another process using the image?
>  == Symbolic link ==
>  QEMU_PROG: -drive if=none,file=TEST_DIR/t.qcow2: Failed to get "write" lock
>  Is another process using the image?
> +
> +== Active commit to intermediate layer should work when base in use ==
> +
> +_qemu_img_wrapper commit -b TEST_DIR/t.qcow2.b TEST_DIR/t.qcow2.c
>  {"return": {}}
>  Adding drive

Hmmm...  I don't know, but this just passes on my machine without your
previous patch.

[Two minutes later]

Now I do know why, qemu simply isn't properly started at the time
$QEMU_IMG commit runs (see also 6bfc907deed83af7).  Therefore, no error
here.

So if I just add a

_send_qemu_cmd $QEMU_HANDLE \
    "{ 'execute': 'qmp_capabilities' }" \
    'return'

after the _launch_qemu, this is what I get:

QEMU_PROG: -device virtio-blk,drive=drive0: Drive 'drive0' is already in
use because it has been automatically connected to another device (did
you need 'if=none' in the drive options?)

With if=none (or just -blockdev instead of -drive), I get the error
message I was hoping for.

Max


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