[Qemu-devel] [PATCH v2 00/11] block: Accept node-name in all node level QMP commands

[Qemu-devel] [PATCH v2 00/11] block: Accept node-name in all node level QMP commands

[Kevin Wolf]

As stated in the RFC I sent two weeks ago:

   * Node level commands: We need to complete the conversion that makes
     commands accept node names instead of BlockBackend names. In some places
     we intentionally allow only BlockBackends because we don't know if the
     command works in other places than the root. This is okay, but we can
     accept node names anyway. We just need to check that the node is a root
     node as expected.

This part of the RFC is implemented by this series.

Kevin Wolf (11):
  block: Accept node-name for block-stream
  block: Accept node-name for block-commit
  block: Accept node-name for blockdev-backup
  block: Accept node-name for blockdev-mirror
  block: Accept node-name for blockdev-snapshot-delete-internal-sync
  block: Accept node-name for blockdev-snapshot-internal-sync
  block: Accept node-name for change-backing-file
  block: Accept node-name for drive-backup
  block: Accept node-name for drive-mirror
  nbd-server: Use a separate BlockBackend
  nbd-server: Allow node name for nbd-server-add

 block.c                |   2 +
 blockdev-nbd.c         |  21 +++---
 blockdev.c             | 196 ++++++++++++++++---------------------------------
 include/block/nbd.h    |   3 +-
 nbd/server.c           |  25 +++++--
 qapi/block-core.json   |   5 +-
 qemu-nbd.c             |   4 +-
 qmp-commands.hx        |   2 +-
 tests/qemu-iotests/030 |   2 +-
 tests/qemu-iotests/041 |   8 +-
 tests/qemu-iotests/055 |   7 +-
 tests/qemu-iotests/057 |   4 +-
 12 files changed, 108 insertions(+), 171 deletions(-)

-- 
1.8.3.1

[Qemu-devel] [PATCH v2 01/11] block: Accept node-name for block-stream

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
block-stream to accept a node-name without lifting the restriction that
we're operating at a root node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c             | 32 ++++++++++++++++++++------------
 qapi/block-core.json   |  5 +----
 qmp-commands.hx        |  2 +-
 tests/qemu-iotests/030 |  2 +-
 4 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 0f8065c..01e57c9 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1172,6 +1172,23 @@ fail:
     return dinfo;
 }
 
+static BlockDriverState *qmp_get_root_bs(const char *name, Error **errp)
+{
+    BlockDriverState *bs;
+
+    bs = bdrv_lookup_bs(name, name, errp);
+    if (bs == NULL) {
+        return NULL;
+    }
+
+    if (!bdrv_has_blk(bs)) {
+        error_setg(errp, "Need a root block node");
+        return NULL;
+    }
+
+    return bs;
+}
+
 void hmp_commit(Monitor *mon, const QDict *qdict)
 {
     const char *device = qdict_get_str(qdict, "device");
@@ -3011,7 +3028,6 @@ void qmp_block_stream(const char *device,
                       bool has_on_error, BlockdevOnError on_error,
                       Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *base_bs = NULL;
     AioContext *aio_context;
@@ -3022,22 +3038,14 @@ void qmp_block_stream(const char *device,
         on_error = BLOCKDEV_ON_ERROR_REPORT;
     }
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, "Device '%s' has no medium", device);
-        goto out;
-    }
-    bs = blk_bs(blk);
-
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) {
         goto out;
     }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index ac8f5f6..f069e40 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1413,7 +1413,7 @@
 # On successful completion the image file is updated to drop the backing file
 # and the BLOCK_JOB_COMPLETED event is emitted.
 #
-# @device: the device name
+# @device: the device name or node-name of a root node
 #
 # @base:   #optional the common backing file name
 #
@@ -1438,9 +1438,6 @@
 #            'stop' and 'enospc' can only be used if the block device
 #            supports io-status (see BlockInfo).  Since 1.3.
 #
-# Returns: Nothing on success
-#          If @device does not exist, DeviceNotFound
-#
 # Since: 1.1
 ##
 { 'command': 'block-stream',
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 6937e83..0588fd6 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1118,7 +1118,7 @@ Copy data from a backing file into a block device.
 
 Arguments:
 
-- "device": The device's ID, must be unique (json-string)
+- "device": The device name or node-name of a root node (json-string)
 - "base": The file name of the backing image above which copying starts
           (json-string, optional)
 - "backing-file": The backing file string to write into the active layer. This
diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index 3ac2443..107049b 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -126,7 +126,7 @@ class TestSingleDrive(iotests.QMPTestCase):
 
     def test_device_not_found(self):
         result = self.vm.qmp('block-stream', device='nonexistent')
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
 
 class TestSmallerBackingFile(iotests.QMPTestCase):
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 02/11] block: Accept node-name for block-commit

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
block-commit to accept a node-name without lifting the restriction that
we're operating at a root node.

As libvirt makes use of the DeviceNotFound error class, we must add
explicit code to retain this behaviour because qmp_get_root_bs() only
returns GenericErrors.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 01e57c9..e3586f7 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3091,7 +3091,6 @@ void qmp_block_commit(const char *device,
                       bool has_speed, int64_t speed,
                       Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *base_bs, *top_bs;
     AioContext *aio_context;
@@ -3110,22 +3109,22 @@ void qmp_block_commit(const char *device,
      *  live commit feature versions; for this to work, we must make sure to
      *  perform the device lookup before any generic errors that may occur in a
      *  scenario in which all optional arguments are omitted. */
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, &local_err);
+    if (!bs) {
+        bs = bdrv_lookup_bs(device, device, NULL);
+        if (!bs) {
+            error_free(local_err);
+            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                      "Device '%s' not found", device);
+        } else {
+            error_propagate(errp, local_err);
+        }
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, "Device '%s' has no medium", device);
-        goto out;
-    }
-    bs = blk_bs(blk);
-
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) {
         goto out;
     }
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 03/11] block: Accept node-name for blockdev-backup

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
blockdev-backup and the corresponding transaction action to accept a
node-name without lifting the restriction that we're operating at a root
node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c | 35 ++++++++++-------------------------
 1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index e3586f7..d9909d0 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1951,38 +1951,31 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockdevBackup *backup;
-    BlockBackend *blk, *target;
+    BlockDriverState *bs, *target;
     Error *local_err = NULL;
 
     assert(common->action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
     backup = common->action->u.blockdev_backup.data;
 
-    blk = blk_by_name(backup->device);
-    if (!blk) {
-        error_setg(errp, "Device '%s' not found", backup->device);
-        return;
-    }
-
-    if (!blk_is_available(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
+    bs = qmp_get_root_bs(backup->device, errp);
+    if (!bs) {
         return;
     }
 
-    target = blk_by_name(backup->target);
+    target = qmp_get_root_bs(backup->target, errp);
     if (!target) {
-        error_setg(errp, "Device '%s' not found", backup->target);
         return;
     }
 
     /* AioContext is released in .clean() */
-    state->aio_context = blk_get_aio_context(blk);
-    if (state->aio_context != blk_get_aio_context(target)) {
+    state->aio_context = bdrv_get_aio_context(bs);
+    if (state->aio_context != bdrv_get_aio_context(target)) {
         state->aio_context = NULL;
         error_setg(errp, "Backup between two IO threads is not implemented");
         return;
     }
     aio_context_acquire(state->aio_context);
-    state->bs = blk_bs(blk);
+    state->bs = bs;
     bdrv_drained_begin(state->bs);
 
     do_blockdev_backup(backup->device, backup->target,
@@ -3355,7 +3348,6 @@ void do_blockdev_backup(const char *device, const char *target,
                          BlockdevOnError on_target_error,
                          BlockJobTxn *txn, Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     Error *local_err = NULL;
@@ -3371,21 +3363,14 @@ void do_blockdev_backup(const char *device, const char *target,
         on_target_error = BLOCKDEV_ON_ERROR_REPORT;
     }
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_setg(errp, "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, "Device '%s' has no medium", device);
-        goto out;
-    }
-    bs = blk_bs(blk);
-
     target_bs = bdrv_lookup_bs(target, target, errp);
     if (!target_bs) {
         goto out;
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 04/11] block: Accept node-name for blockdev-mirror

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
blockdev-mirror to accept a node-name without lifting the restriction
that we're operating at a root node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index d9909d0..7e9c7a4 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3654,21 +3654,13 @@ void qmp_blockdev_mirror(const char *device, const char *target,
                          Error **errp)
 {
     BlockDriverState *bs;
-    BlockBackend *blk;
     BlockDriverState *target_bs;
     AioContext *aio_context;
     BlockMirrorBackingMode backing_mode = MIRROR_LEAVE_BACKING_CHAIN;
     Error *local_err = NULL;
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_setg(errp, "Device '%s' not found", device);
-        return;
-    }
-    bs = blk_bs(blk);
-
+    bs = qmp_get_root_bs(device, errp);
     if (!bs) {
-        error_setg(errp, "Device '%s' has no media", device);
         return;
     }
 
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 05/11] block: Accept node-name for blockdev-snapshot-delete-internal-sync

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
blockdev-snapshot-delete-internal-sync to accept a node-name without
lifting the restriction that we're operating at a root node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c             | 16 +++-------------
 tests/qemu-iotests/057 |  2 +-
 2 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 7e9c7a4..8e38d2d 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1299,21 +1299,17 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
                                                          Error **errp)
 {
     BlockDriverState *bs;
-    BlockBackend *blk;
     AioContext *aio_context;
     QEMUSnapshotInfo sn;
     Error *local_err = NULL;
     SnapshotInfo *info = NULL;
     int ret;
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return NULL;
     }
-
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
     if (!has_id) {
@@ -1329,12 +1325,6 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
         goto out_aio_context;
     }
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, "Device '%s' has no medium", device);
-        goto out_aio_context;
-    }
-    bs = blk_bs(blk);
-
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE, errp)) {
         goto out_aio_context;
     }
diff --git a/tests/qemu-iotests/057 b/tests/qemu-iotests/057
index 9cdd582..bb6c06a 100755
--- a/tests/qemu-iotests/057
+++ b/tests/qemu-iotests/057
@@ -239,7 +239,7 @@ class TestSnapshotDelete(ImageSnapshotTestCase):
         result = self.vm.qmp('blockdev-snapshot-delete-internal-sync',
                               device = 'drive_error',
                               id = '0')
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_error_no_id_and_name(self):
         result = self.vm.qmp('blockdev-snapshot-delete-internal-sync',
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 06/11] block: Accept node-name for blockdev-snapshot-internal-sync

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
blockdev-snapshot-internal-sync to accept a node-name without lifting
the restriction that we're operating at a root node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c             | 15 +++------------
 tests/qemu-iotests/057 |  2 +-
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 8e38d2d..7a0890f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1504,7 +1504,6 @@ static void internal_snapshot_prepare(BlkActionState *common,
     Error *local_err = NULL;
     const char *device;
     const char *name;
-    BlockBackend *blk;
     BlockDriverState *bs;
     QEMUSnapshotInfo old_sn, *sn;
     bool ret;
@@ -1527,23 +1526,15 @@ static void internal_snapshot_prepare(BlkActionState *common,
         return;
     }
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
     /* AioContext is released in .clean() */
-    state->aio_context = blk_get_aio_context(blk);
+    state->aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(state->aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        return;
-    }
-    bs = blk_bs(blk);
-
     state->bs = bs;
     bdrv_drained_begin(bs);
 
diff --git a/tests/qemu-iotests/057 b/tests/qemu-iotests/057
index bb6c06a..9f0a5a3 100755
--- a/tests/qemu-iotests/057
+++ b/tests/qemu-iotests/057
@@ -182,7 +182,7 @@ class TestSingleTransaction(ImageSnapshotTestCase):
                               'name': 'a' },
                   }]
         result = self.vm.qmp('transaction', actions = actions)
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_error_exist(self):
         self.createSnapshotInTransaction(1)
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 07/11] block: Accept node-name for change-backing-file

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
change-backing-file to accept a node-name without lifting the
restriction that we're operating at a root node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 7a0890f..ca28ff7 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3796,7 +3796,6 @@ void qmp_change_backing_file(const char *device,
                              const char *backing_file,
                              Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs = NULL;
     AioContext *aio_context;
     BlockDriverState *image_bs = NULL;
@@ -3805,22 +3804,14 @@ void qmp_change_backing_file(const char *device,
     int open_flags;
     int ret;
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, "Device '%s' has no medium", device);
-        goto out;
-    }
-    bs = blk_bs(blk);
-
     image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 08/11] block: Accept node-name for drive-backup

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
drive-backup and the corresponding transaction action to accept a
node-name without lifting the restriction that we're operating at a root
node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c             | 36 +++++++++---------------------------
 tests/qemu-iotests/055 |  7 ++-----
 2 files changed, 11 insertions(+), 32 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index ca28ff7..5438b3c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1849,30 +1849,23 @@ static void do_drive_backup(const char *device, const char *target,
 static void drive_backup_prepare(BlkActionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
-    BlockBackend *blk;
+    BlockDriverState *bs;
     DriveBackup *backup;
     Error *local_err = NULL;
 
     assert(common->action->type == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
     backup = common->action->u.drive_backup.data;
 
-    blk = blk_by_name(backup->device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", backup->device);
-        return;
-    }
-
-    if (!blk_is_available(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
+    bs = qmp_get_root_bs(backup->device, errp);
+    if (!bs) {
         return;
     }
 
     /* AioContext is released in .clean() */
-    state->aio_context = blk_get_aio_context(blk);
+    state->aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(state->aio_context);
-    bdrv_drained_begin(blk_bs(blk));
-    state->bs = blk_bs(blk);
+    bdrv_drained_begin(bs);
+    state->bs = bs;
 
     do_drive_backup(backup->device, backup->target,
                     backup->has_format, backup->format,
@@ -3175,7 +3168,6 @@ static void do_drive_backup(const char *device, const char *target,
                             BlockdevOnError on_target_error,
                             BlockJobTxn *txn, Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     BlockDriverState *source = NULL;
@@ -3199,24 +3191,14 @@ static void do_drive_backup(const char *device, const char *target,
         mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
     }
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    /* Although backup_run has this check too, we need to use bs->drv below, so
-     * do an early check redundantly. */
-    if (!blk_is_available(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        goto out;
-    }
-    bs = blk_bs(blk);
-
     if (!has_format) {
         format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name;
     }
diff --git a/tests/qemu-iotests/055 b/tests/qemu-iotests/055
index c8e3578..8113c61 100755
--- a/tests/qemu-iotests/055
+++ b/tests/qemu-iotests/055
@@ -134,10 +134,7 @@ class TestSingleDrive(iotests.QMPTestCase):
 
     def do_test_device_not_found(self, cmd, **args):
         result = self.vm.qmp(cmd, **args)
-        if cmd == 'drive-backup':
-            self.assert_qmp(result, 'error/class', 'DeviceNotFound')
-        else:
-            self.assert_qmp(result, 'error/class', 'GenericError')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_device_not_found(self):
         self.do_test_device_not_found('drive-backup', device='nonexistent',
@@ -371,7 +368,7 @@ class TestSingleTransaction(iotests.QMPTestCase):
                           'sync': 'full' },
             }
         ])
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
         result = self.vm.qmp('transaction', actions=[{
                 'type': 'blockdev-backup',
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 09/11] block: Accept node-name for drive-mirror

[Kevin Wolf]

In order to remove the necessity to use BlockBackend names in the
external API, we want to allow node-names everywhere. This converts
drive-mirror to accept a node-name without lifting the restriction that
we're operating at a root node.

In case of an invalid device name, the command returns the GenericError
error class now instead of DeviceNotFound, because this is what
qmp_get_root_bs() returns.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev.c             | 14 +++-----------
 tests/qemu-iotests/041 |  8 +++-----
 2 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 5438b3c..2a2eb83 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3459,7 +3459,6 @@ void qmp_drive_mirror(const char *device, const char *target,
                       Error **errp)
 {
     BlockDriverState *bs;
-    BlockBackend *blk;
     BlockDriverState *source, *target_bs;
     AioContext *aio_context;
     BlockMirrorBackingMode backing_mode;
@@ -3468,21 +3467,14 @@ void qmp_drive_mirror(const char *device, const char *target,
     int flags;
     int64_t size;
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
+    bs = qmp_get_root_bs(device, errp);
+    if (!bs) {
         return;
     }
 
-    aio_context = blk_get_aio_context(blk);
+    aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (!blk_is_available(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        goto out;
-    }
-    bs = blk_bs(blk);
     if (!has_mode) {
         mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
     }
diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index cbf5e0b..80939c0 100755
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -38,7 +38,6 @@ class TestSingleDrive(iotests.QMPTestCase):
     image_len = 1 * 1024 * 1024 # MB
     qmp_cmd = 'drive-mirror'
     qmp_target = target_img
-    not_found_error = 'DeviceNotFound'
 
     def setUp(self):
         iotests.create_image(backing_img, self.image_len)
@@ -176,7 +175,7 @@ class TestSingleDrive(iotests.QMPTestCase):
 
         result = self.vm.qmp(self.qmp_cmd, device='ide1-cd0', sync='full',
                              target=self.qmp_target)
-        self.assert_qmp(result, 'error/class', self.not_found_error)
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_image_not_found(self):
         result = self.vm.qmp(self.qmp_cmd, device='drive0', sync='full',
@@ -186,12 +185,11 @@ class TestSingleDrive(iotests.QMPTestCase):
     def test_device_not_found(self):
         result = self.vm.qmp(self.qmp_cmd, device='nonexistent', sync='full',
                              target=self.qmp_target)
-        self.assert_qmp(result, 'error/class', self.not_found_error)
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
 class TestSingleBlockdev(TestSingleDrive):
     qmp_cmd = 'blockdev-mirror'
     qmp_target = 'node1'
-    not_found_error = 'GenericError'
 
     def setUp(self):
         TestSingleDrive.setUp(self)
@@ -922,7 +920,7 @@ class TestRepairQuorum(iotests.QMPTestCase):
                              node_name='repair0',
                              replaces='img1',
                              target=quorum_repair_img, format=iotests.imgfmt)
-        self.assert_qmp(result, 'error/class', 'DeviceNotFound')
+        self.assert_qmp(result, 'error/class', 'GenericError')
 
     def test_wrong_sync_mode(self):
         if not self.has_quorum():
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 10/11] nbd-server: Use a separate BlockBackend

[Kevin Wolf]

The builtin NBD server uses its own BlockBackend now instead of reusing
the monitor/guest device one.

This means that it has its own writethrough setting now. The builtin
NBD server always uses writeback caching now regardless of whether the
guest device has WCE enabled. qemu-nbd respects the cache mode given on
the command line.

We still need to keep a reference to the monitor BB because we put an
eject notifier on it, but we don't use it for any I/O.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c             |  2 ++
 blockdev-nbd.c      |  4 ++--
 include/block/nbd.h |  3 ++-
 nbd/server.c        | 25 ++++++++++++++++++++-----
 qemu-nbd.c          |  4 ++--
 5 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/block.c b/block.c
index 823ff1d..c083829 100644
--- a/block.c
+++ b/block.c
@@ -25,6 +25,7 @@
 #include "trace.h"
 #include "block/block_int.h"
 #include "block/blockjob.h"
+#include "block/nbd.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qapi/qmp/qerror.h"
@@ -2204,6 +2205,7 @@ static void bdrv_close(BlockDriverState *bs)
 void bdrv_close_all(void)
 {
     block_job_cancel_sync_all();
+    nbd_export_close_all();
 
     /* Drop references from requests still in flight, such as canceled block
      * jobs whose AIO context has not been polled yet */
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index 12cae0e..c437d32 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -176,8 +176,8 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
         writable = false;
     }
 
-    exp = nbd_export_new(blk, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY, NULL,
-                         errp);
+    exp = nbd_export_new(blk_bs(blk), 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
+                         NULL, false, blk, errp);
     if (!exp) {
         return;
     }
diff --git a/include/block/nbd.h b/include/block/nbd.h
index eeda3eb..d89f092 100644
--- a/include/block/nbd.h
+++ b/include/block/nbd.h
@@ -105,8 +105,9 @@ int nbd_disconnect(int fd);
 typedef struct NBDExport NBDExport;
 typedef struct NBDClient NBDClient;
 
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
                           uint32_t nbdflags, void (*close)(NBDExport *),
+                          bool writethrough, BlockBackend *on_eject_blk,
                           Error **errp);
 void nbd_export_close(NBDExport *exp);
 void nbd_export_get(NBDExport *exp);
diff --git a/nbd/server.c b/nbd/server.c
index a677e26..1cd6d60 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -69,6 +69,7 @@ struct NBDExport {
 
     AioContext *ctx;
 
+    BlockBackend *eject_notifier_blk;
     Notifier eject_notifier;
 };
 
@@ -809,11 +810,18 @@ static void nbd_eject_notifier(Notifier *n, void *data)
     nbd_export_close(exp);
 }
 
-NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
+NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
                           uint32_t nbdflags, void (*close)(NBDExport *),
+                          bool writethrough, BlockBackend *on_eject_blk,
                           Error **errp)
 {
+    BlockBackend *blk;
     NBDExport *exp = g_malloc0(sizeof(NBDExport));
+
+    blk = blk_new();
+    blk_insert_bs(blk, bs);
+    blk_set_enable_write_cache(blk, !writethrough);
+
     exp->refcount = 1;
     QTAILQ_INIT(&exp->clients);
     exp->blk = blk;
@@ -829,11 +837,14 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
 
     exp->close = close;
     exp->ctx = blk_get_aio_context(blk);
-    blk_ref(blk);
     blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp);
 
-    exp->eject_notifier.notify = nbd_eject_notifier;
-    blk_add_remove_bs_notifier(blk, &exp->eject_notifier);
+    if (on_eject_blk) {
+        blk_ref(on_eject_blk);
+        exp->eject_notifier_blk = on_eject_blk;
+        exp->eject_notifier.notify = nbd_eject_notifier;
+        blk_add_remove_bs_notifier(on_eject_blk, &exp->eject_notifier);
+    }
 
     /*
      * NBD exports are used for non-shared storage migration.  Make sure
@@ -846,6 +857,7 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size,
     return exp;
 
 fail:
+    blk_unref(blk);
     g_free(exp);
     return NULL;
 }
@@ -916,7 +928,10 @@ void nbd_export_put(NBDExport *exp)
         }
 
         if (exp->blk) {
-            notifier_remove(&exp->eject_notifier);
+            if (exp->eject_notifier_blk) {
+                notifier_remove(&exp->eject_notifier);
+                blk_unref(exp->eject_notifier_blk);
+            }
             blk_remove_aio_context_notifier(exp->blk, blk_aio_attached,
                                             blk_aio_detach, exp);
             blk_unref(exp->blk);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 321f02b..9e6aaa9 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -910,8 +910,8 @@ int main(int argc, char **argv)
         }
     }
 
-    exp = nbd_export_new(blk, dev_offset, fd_size, nbdflags, nbd_export_closed,
-                         &local_err);
+    exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed,
+                         writethrough, NULL, &local_err);
     if (!exp) {
         error_report_err(local_err);
         exit(EXIT_FAILURE);
-- 
1.8.3.1

[Qemu-devel] [PATCH v2 11/11] nbd-server: Allow node name for nbd-server-add

[Kevin Wolf]

There is no reason why an NBD server couldn't be started for any node,
even if it's not on the top level. This converts nbd-server-add to
accept a node-name.

Note that there is a semantic difference between using a BlockBackend
name and the node name of its root: In the former case, the NBD server
is closed on eject; in the latter case, the NBD server doesn't drop its
reference and keeps the image file open this way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockdev-nbd.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index c437d32..ca41cc6 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -145,7 +145,8 @@ void qmp_nbd_server_start(SocketAddress *addr,
 void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
                         Error **errp)
 {
-    BlockBackend *blk;
+    BlockDriverState *bs = NULL;
+    BlockBackend *on_eject_blk;
     NBDExport *exp;
 
     if (!nbd_server) {
@@ -158,26 +159,22 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
         return;
     }
 
-    blk = blk_by_name(device);
-    if (!blk) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", device);
-        return;
-    }
-    if (!blk_is_inserted(blk)) {
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
+    on_eject_blk = blk_by_name(device);
+
+    bs = bdrv_lookup_bs(device, device, errp);
+    if (!bs) {
         return;
     }
 
     if (!has_writable) {
         writable = false;
     }
-    if (blk_is_read_only(blk)) {
+    if (bdrv_is_read_only(bs)) {
         writable = false;
     }
 
-    exp = nbd_export_new(blk_bs(blk), 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
-                         NULL, false, blk, errp);
+    exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
+                         NULL, false, on_eject_blk, errp);
     if (!exp) {
         return;
     }
-- 
1.8.3.1

Re: [Qemu-devel] [RFC PATCH v2 00/11] block: Accept node-name in all node level QMP commands

[Kevin Wolf]

Am 06.07.2016 um 17:20 hat Kevin Wolf geschrieben:
> As stated in the RFC I sent two weeks ago:
> 
>    * Node level commands: We need to complete the conversion that makes
>      commands accept node names instead of BlockBackend names. In some places
>      we intentionally allow only BlockBackends because we don't know if the
>      command works in other places than the root. This is okay, but we can
>      accept node names anyway. We just need to check that the node is a root
>      node as expected.
> 
> This part of the RFC is implemented by this series.

Sorry, this should still be RFC. I haven't updated the documentation for
most commands yet, but the implementation and tests should be ready.

Kevin