[Qemu-devel] [PATCH v5 00/14] block: incremental backup transactions using BlockJobTxn

[Qemu-devel] [PATCH v5 00/14] block: incremental backup transactions using BlockJobTxn

[Fam Zheng]

v5: Address comments from Max Reitz:
    2.4 -> 2.5 in qapi docs.
    Don't leak txn object.
    English syntax fixes.
    Really leave the "cancelled" status of failed job.
    Remove a superfluous added line.

v4: Address comments from John and Stefan, including:
    Rename function: backup_cleanup_sync_bitmap.
    Rename and add comments for .commit and .abort.
    Call .commit and .abort for both txn and non-txn.
    Drop patch 9 in v3.
    Improve the txn implementation. Acquire context locks as accessing them.
    Add refcnt patch for BlockJob.
    Adjust txn unit test code.

This is based on top of the work by Stefan Hajnoczi and John Snow.

Recap: motivation for block job transactions
--------------------------------------------
If an incremental backup block job fails then we reclaim the bitmap so
the job can be retried.  The problem comes when multiple jobs are started as
part of a qmp 'transaction' command.  We need to group these jobs in a
transaction so that either all jobs complete successfully or all bitmaps are
reclaimed.

Without transactions, there is a case where some jobs complete successfully and
throw away their bitmaps, making it impossible to retry the backup by rerunning
the command if one of the jobs fails.

How does this implementation work?
----------------------------------
These patches add a BlockJobTxn object with the following API:

  txn = block_job_txn_new();
  block_job_txn_add_job(txn, job1);
  block_job_txn_add_job(txn, job2);

The jobs either both complete successfully or they both fail/cancel.  If the
user cancels job1 then job2 will also be cancelled and vice versa.

Jobs objects stay alive waiting for other jobs to complete, even if the
coroutines have returned.  They can be cancelled by the user during this time.
Job blockers are still in effect and no other block job can run on this device
in the meantime (since QEMU currently only allows 1 job per device).  This is
the main drawback to this approach but reasonable since you probably don't want
to run other jobs/operations until you're sure the backup was successful (you
won't be able to retry a failed backup if there's a new job running).



Fam Zheng (6):
  backup: Extract dirty bitmap handling as a separate function
  blockjob: Introduce reference count
  blockjob: Add .commit and .abort block job actions
  blockjob: Add "completed" and "ret" in BlockJob
  blockjob: Simplify block_job_finish_sync
  block: Add block job transactions

John Snow (4):
  qapi: Add transaction support to block-dirty-bitmap operations
  iotests: add transactional incremental backup test
  block: rename BlkTransactionState and BdrvActionOps
  iotests: 124 - transactional failure test

Kashyap Chamarthy (1):
  qmp-commands.hx: Update the supported 'transaction' operations

Stefan Hajnoczi (3):
  blockdev: make BlockJobTxn available to qmp 'transaction'
  block/backup: support block job transactions
  tests: add BlockJobTxn unit test

 block.c                    |  19 ++-
 block/backup.c             |  49 ++++--
 block/mirror.c             |   2 +-
 blockdev.c                 | 361 ++++++++++++++++++++++++++++++++++++---------
 blockjob.c                 | 184 +++++++++++++++++++----
 docs/bitmaps.md            |   6 +-
 hmp.c                      |   2 +-
 include/block/block.h      |   2 +-
 include/block/block_int.h  |   6 +-
 include/block/blockjob.h   |  83 ++++++++++-
 qapi-schema.json           |   6 +-
 qapi/block-core.json       |  16 +-
 qmp-commands.hx            |  21 ++-
 tests/Makefile             |   3 +
 tests/qemu-iotests/124     | 182 ++++++++++++++++++++++-
 tests/qemu-iotests/124.out |   4 +-
 tests/test-blockjob-txn.c  | 244 ++++++++++++++++++++++++++++++
 17 files changed, 1048 insertions(+), 142 deletions(-)
 create mode 100644 tests/test-blockjob-txn.c

-- 
2.4.3

[Qemu-devel] [PATCH v5 01/14] qapi: Add transaction support to block-dirty-bitmap operations

[Fam Zheng]

From: John Snow <jsnow@redhat.com>

This adds two qmp commands to transactions.

block-dirty-bitmap-add allows you to create a bitmap simultaneously
alongside a new full backup to accomplish a clean synchronization
point.

block-dirty-bitmap-clear allows you to reset a bitmap back to as-if
it were new, which can also be used alongside a full backup to
accomplish a clean synchronization point.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block.c                   |  19 +++++++-
 blockdev.c                | 114 +++++++++++++++++++++++++++++++++++++++++++++-
 docs/bitmaps.md           |   6 +--
 include/block/block.h     |   1 -
 include/block/block_int.h |   3 ++
 qapi-schema.json          |   6 ++-
 6 files changed, 139 insertions(+), 10 deletions(-)

diff --git a/block.c b/block.c
index 090923c..09ae18e 100644
--- a/block.c
+++ b/block.c
@@ -3566,10 +3566,25 @@ void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
     hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
 }
 
-void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
 {
     assert(bdrv_dirty_bitmap_enabled(bitmap));
-    hbitmap_reset_all(bitmap->bitmap);
+    if (!out) {
+        hbitmap_reset_all(bitmap->bitmap);
+    } else {
+        HBitmap *backup = bitmap->bitmap;
+        bitmap->bitmap = hbitmap_alloc(bitmap->size,
+                                       hbitmap_granularity(backup));
+        *out = backup;
+    }
+}
+
+void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in)
+{
+    HBitmap *tmp = bitmap->bitmap;
+    assert(bdrv_dirty_bitmap_enabled(bitmap));
+    bitmap->bitmap = in;
+    hbitmap_free(tmp);
 }
 
 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
diff --git a/blockdev.c b/blockdev.c
index 6b48be6..b1e7f2a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1714,6 +1714,106 @@ static void blockdev_backup_clean(BlkTransactionState *common)
     }
 }
 
+typedef struct BlockDirtyBitmapState {
+    BlkTransactionState common;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+    AioContext *aio_context;
+    HBitmap *backup;
+    bool prepared;
+} BlockDirtyBitmapState;
+
+static void block_dirty_bitmap_add_prepare(BlkTransactionState *common,
+                                           Error **errp)
+{
+    Error *local_err = NULL;
+    BlockDirtyBitmapAdd *action;
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    action = common->action->block_dirty_bitmap_add;
+    /* AIO context taken and released within qmp_block_dirty_bitmap_add */
+    qmp_block_dirty_bitmap_add(action->node, action->name,
+                               action->has_granularity, action->granularity,
+                               &local_err);
+
+    if (!local_err) {
+        state->prepared = true;
+    } else {
+        error_propagate(errp, local_err);
+    }
+}
+
+static void block_dirty_bitmap_add_abort(BlkTransactionState *common)
+{
+    BlockDirtyBitmapAdd *action;
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    action = common->action->block_dirty_bitmap_add;
+    /* Should not be able to fail: IF the bitmap was added via .prepare(),
+     * then the node reference and bitmap name must have been valid.
+     */
+    if (state->prepared) {
+        qmp_block_dirty_bitmap_remove(action->node, action->name, &error_abort);
+    }
+}
+
+static void block_dirty_bitmap_clear_prepare(BlkTransactionState *common,
+                                             Error **errp)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+    BlockDirtyBitmap *action;
+
+    action = common->action->block_dirty_bitmap_clear;
+    state->bitmap = block_dirty_bitmap_lookup(action->node,
+                                              action->name,
+                                              &state->bs,
+                                              &state->aio_context,
+                                              errp);
+    if (!state->bitmap) {
+        return;
+    }
+
+    if (bdrv_dirty_bitmap_frozen(state->bitmap)) {
+        error_setg(errp, "Cannot modify a frozen bitmap");
+        return;
+    } else if (!bdrv_dirty_bitmap_enabled(state->bitmap)) {
+        error_setg(errp, "Cannot clear a disabled bitmap");
+        return;
+    }
+
+    bdrv_clear_dirty_bitmap(state->bitmap, &state->backup);
+    /* AioContext is released in .clean() */
+}
+
+static void block_dirty_bitmap_clear_abort(BlkTransactionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+}
+
+static void block_dirty_bitmap_clear_commit(BlkTransactionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    hbitmap_free(state->backup);
+}
+
+static void block_dirty_bitmap_clear_clean(BlkTransactionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    if (state->aio_context) {
+        aio_context_release(state->aio_context);
+    }
+}
+
 static void abort_prepare(BlkTransactionState *common, Error **errp)
 {
     error_setg(errp, "Transaction aborted using Abort action");
@@ -1754,6 +1854,18 @@ static const BdrvActionOps actions[] = {
         .abort = internal_snapshot_abort,
         .clean = internal_snapshot_clean,
     },
+    [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ADD] = {
+        .instance_size = sizeof(BlockDirtyBitmapState),
+        .prepare = block_dirty_bitmap_add_prepare,
+        .abort = block_dirty_bitmap_add_abort,
+    },
+    [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_CLEAR] = {
+        .instance_size = sizeof(BlockDirtyBitmapState),
+        .prepare = block_dirty_bitmap_clear_prepare,
+        .commit = block_dirty_bitmap_clear_commit,
+        .abort = block_dirty_bitmap_clear_abort,
+        .clean = block_dirty_bitmap_clear_clean,
+    }
 };
 
 /*
@@ -2137,7 +2249,7 @@ void qmp_block_dirty_bitmap_clear(const char *node, const char *name,
         goto out;
     }
 
-    bdrv_clear_dirty_bitmap(bitmap);
+    bdrv_clear_dirty_bitmap(bitmap, NULL);
 
  out:
     aio_context_release(aio_context);
diff --git a/docs/bitmaps.md b/docs/bitmaps.md
index fa87f07..9fd8ea6 100644
--- a/docs/bitmaps.md
+++ b/docs/bitmaps.md
@@ -97,11 +97,7 @@ which is included at the end of this document.
 }
 ```
 
-## Transactions (Not yet implemented)
-
-* Transactional commands are forthcoming in a future version,
-  and are not yet available for use. This section serves as
-  documentation of intent for their design and usage.
+## Transactions
 
 ### Justification
 
diff --git a/include/block/block.h b/include/block/block.h
index 608cd4e..e619b99 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -504,7 +504,6 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int nr_sectors);
-void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
 void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 14ad4c3..281d790 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -664,4 +664,7 @@ void blk_dev_resize_cb(BlockBackend *blk);
 
 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors);
 
+void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
+void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in);
+
 #endif /* BLOCK_INT_H */
diff --git a/qapi-schema.json b/qapi-schema.json
index 67fef37..3b47ef5 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1493,6 +1493,8 @@
 # abort since 1.6
 # blockdev-snapshot-internal-sync since 1.7
 # blockdev-backup since 2.3
+# block-dirty-bitmap-add since 2.5
+# block-dirty-bitmap-clear since 2.5
 ##
 { 'union': 'TransactionAction',
   'data': {
@@ -1500,7 +1502,9 @@
        'drive-backup': 'DriveBackup',
        'blockdev-backup': 'BlockdevBackup',
        'abort': 'Abort',
-       'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal'
+       'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal',
+       'block-dirty-bitmap-add': 'BlockDirtyBitmapAdd',
+       'block-dirty-bitmap-clear': 'BlockDirtyBitmap'
    } }
 
 ##
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 01/14] qapi: Add transaction support to block-dirty-bitmap operations

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 959 bytes --]

On 09/07/2015 01:34 AM, Fam Zheng wrote:
> From: John Snow <jsnow@redhat.com>
> 
> This adds two qmp commands to transactions.
> 
> block-dirty-bitmap-add allows you to create a bitmap simultaneously
> alongside a new full backup to accomplish a clean synchronization
> point.
> 
> block-dirty-bitmap-clear allows you to reset a bitmap back to as-if
> it were new, which can also be used alongside a full backup to
> accomplish a clean synchronization point.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>

Odd to have a double S-o-B.

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

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


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

[Qemu-devel] [PATCH v5 02/14] iotests: add transactional incremental backup test

[Fam Zheng]

From: John Snow <jsnow@redhat.com>

Test simple usage cases for using transactions to create
and synchronize incremental backups.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 tests/qemu-iotests/124     | 54 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/124.out |  4 ++--
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/tests/qemu-iotests/124 b/tests/qemu-iotests/124
index 9ccd118..9c1977e 100644
--- a/tests/qemu-iotests/124
+++ b/tests/qemu-iotests/124
@@ -36,6 +36,23 @@ def try_remove(img):
         pass
 
 
+def transaction_action(action, **kwargs):
+    return {
+        'type': action,
+        'data': kwargs
+    }
+
+
+def transaction_bitmap_clear(node, name, **kwargs):
+    return transaction_action('block-dirty-bitmap-clear',
+                              node=node, name=name, **kwargs)
+
+
+def transaction_drive_backup(device, target, **kwargs):
+    return transaction_action('drive-backup', device=device, target=target,
+                              **kwargs)
+
+
 class Bitmap:
     def __init__(self, name, drive):
         self.name = name
@@ -264,6 +281,43 @@ class TestIncrementalBackup(iotests.QMPTestCase):
         return self.do_incremental_simple(granularity=131072)
 
 
+    def test_incremental_transaction(self):
+        '''Test: Verify backups made from transactionally created bitmaps.
+
+        Create a bitmap "before" VM execution begins, then create a second
+        bitmap AFTER writes have already occurred. Use transactions to create
+        a full backup and synchronize both bitmaps to this backup.
+        Create an incremental backup through both bitmaps and verify that
+        both backups match the current drive0 image.
+        '''
+
+        drive0 = self.drives[0]
+        bitmap0 = self.add_bitmap('bitmap0', drive0)
+        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
+                                          ('0xfe', '16M', '256k'),
+                                          ('0x64', '32736k', '64k')))
+        bitmap1 = self.add_bitmap('bitmap1', drive0)
+
+        result = self.vm.qmp('transaction', actions=[
+            transaction_bitmap_clear(bitmap0.drive['id'], bitmap0.name),
+            transaction_bitmap_clear(bitmap1.drive['id'], bitmap1.name),
+            transaction_drive_backup(drive0['id'], drive0['backup'],
+                                     sync='full', format=drive0['fmt'])
+        ])
+        self.assert_qmp(result, 'return', {})
+        self.wait_until_completed(drive0['id'])
+        self.files.append(drive0['backup'])
+
+        self.hmp_io_writes(drive0['id'], (('0x9a', 0, 512),
+                                          ('0x55', '8M', '352k'),
+                                          ('0x78', '15872k', '1M')))
+        # Both bitmaps should be correctly in sync.
+        self.create_incremental(bitmap0)
+        self.create_incremental(bitmap1)
+        self.vm.shutdown()
+        self.check_backups()
+
+
     def test_incremental_failure(self):
         '''Test: Verify backups made after a failure are correct.
 
diff --git a/tests/qemu-iotests/124.out b/tests/qemu-iotests/124.out
index 2f7d390..594c16f 100644
--- a/tests/qemu-iotests/124.out
+++ b/tests/qemu-iotests/124.out
@@ -1,5 +1,5 @@
-.......
+........
 ----------------------------------------------------------------------
-Ran 7 tests
+Ran 8 tests
 
 OK
-- 
2.4.3

[Qemu-devel] [PATCH v5 03/14] block: rename BlkTransactionState and BdrvActionOps

[Fam Zheng]

From: John Snow <jsnow@redhat.com>

These structures are misnomers, somewhat.

(1) BlockTransactionState is not state for a transaction,
    but is rather state for a single transaction action.
    Rename it "BlkActionState" to be more accurate.

(2) The BdrvActionOps describes operations for the BlkActionState,
    above. This name might imply a 'BdrvAction' or a 'BdrvActionState',
    which there isn't.
    Rename this to 'BlkActionOps' to match 'BlkActionState'.

Lastly, update the surrounding in-line documentation and comments
to reflect the current nature of how Transactions operate.

This patch changes only comments and names, and should not affect
behavior in any way.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockdev.c | 116 ++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 65 insertions(+), 51 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index b1e7f2a..4ebded8 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1246,43 +1246,57 @@ static BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node,
 
 /* New and old BlockDriverState structs for atomic group operations */
 
-typedef struct BlkTransactionState BlkTransactionState;
+typedef struct BlkActionState BlkActionState;
 
-/* Only prepare() may fail. In a single transaction, only one of commit() or
-   abort() will be called, clean() will always be called if it present. */
-typedef struct BdrvActionOps {
-    /* Size of state struct, in bytes. */
+/**
+ * BlkActionOps:
+ * Table of operations that define an Action.
+ *
+ * @instance_size: Size of state struct, in bytes.
+ * @prepare: Prepare the work, must NOT be NULL.
+ * @commit: Commit the changes, can be NULL.
+ * @abort: Abort the changes on fail, can be NULL.
+ * @clean: Clean up resources after all transaction actions have called
+ *         commit() or abort(). Can be NULL.
+ *
+ * Only prepare() may fail. In a single transaction, only one of commit() or
+ * abort() will be called. clean() will always be called if it is present.
+ */
+typedef struct BlkActionOps {
     size_t instance_size;
-    /* Prepare the work, must NOT be NULL. */
-    void (*prepare)(BlkTransactionState *common, Error **errp);
-    /* Commit the changes, can be NULL. */
-    void (*commit)(BlkTransactionState *common);
-    /* Abort the changes on fail, can be NULL. */
-    void (*abort)(BlkTransactionState *common);
-    /* Clean up resource in the end, can be NULL. */
-    void (*clean)(BlkTransactionState *common);
-} BdrvActionOps;
+    void (*prepare)(BlkActionState *common, Error **errp);
+    void (*commit)(BlkActionState *common);
+    void (*abort)(BlkActionState *common);
+    void (*clean)(BlkActionState *common);
+} BlkActionOps;
 
-/*
- * This structure must be arranged as first member in child type, assuming
- * that compiler will also arrange it to the same address with parent instance.
- * Later it will be used in free().
+/**
+ * BlkActionState:
+ * Describes one Action's state within a Transaction.
+ *
+ * @action: QAPI-defined enum identifying which Action to perform.
+ * @ops: Table of ActionOps this Action can perform.
+ * @entry: List membership for all Actions in this Transaction.
+ *
+ * This structure must be arranged as first member in a subclassed type,
+ * assuming that the compiler will also arrange it to the same offsets as the
+ * base class.
  */
-struct BlkTransactionState {
+struct BlkActionState {
     TransactionAction *action;
-    const BdrvActionOps *ops;
-    QSIMPLEQ_ENTRY(BlkTransactionState) entry;
+    const BlkActionOps *ops;
+    QSIMPLEQ_ENTRY(BlkActionState) entry;
 };
 
 /* internal snapshot private data */
 typedef struct InternalSnapshotState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     AioContext *aio_context;
     QEMUSnapshotInfo sn;
 } InternalSnapshotState;
 
-static void internal_snapshot_prepare(BlkTransactionState *common,
+static void internal_snapshot_prepare(BlkActionState *common,
                                       Error **errp)
 {
     Error *local_err = NULL;
@@ -1378,7 +1392,7 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     state->bs = bs;
 }
 
-static void internal_snapshot_abort(BlkTransactionState *common)
+static void internal_snapshot_abort(BlkActionState *common)
 {
     InternalSnapshotState *state =
                              DO_UPCAST(InternalSnapshotState, common, common);
@@ -1401,7 +1415,7 @@ static void internal_snapshot_abort(BlkTransactionState *common)
     }
 }
 
-static void internal_snapshot_clean(BlkTransactionState *common)
+static void internal_snapshot_clean(BlkActionState *common)
 {
     InternalSnapshotState *state = DO_UPCAST(InternalSnapshotState,
                                              common, common);
@@ -1413,13 +1427,13 @@ static void internal_snapshot_clean(BlkTransactionState *common)
 
 /* external snapshot private data */
 typedef struct ExternalSnapshotState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
     AioContext *aio_context;
 } ExternalSnapshotState;
 
-static void external_snapshot_prepare(BlkTransactionState *common,
+static void external_snapshot_prepare(BlkActionState *common,
                                       Error **errp)
 {
     BlockDriver *drv;
@@ -1540,7 +1554,7 @@ static void external_snapshot_prepare(BlkTransactionState *common,
     }
 }
 
-static void external_snapshot_commit(BlkTransactionState *common)
+static void external_snapshot_commit(BlkActionState *common)
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
@@ -1558,7 +1572,7 @@ static void external_snapshot_commit(BlkTransactionState *common)
     aio_context_release(state->aio_context);
 }
 
-static void external_snapshot_abort(BlkTransactionState *common)
+static void external_snapshot_abort(BlkActionState *common)
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
@@ -1571,13 +1585,13 @@ static void external_snapshot_abort(BlkTransactionState *common)
 }
 
 typedef struct DriveBackupState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     AioContext *aio_context;
     BlockJob *job;
 } DriveBackupState;
 
-static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
+static void drive_backup_prepare(BlkActionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
     BlockDriverState *bs;
@@ -1618,7 +1632,7 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
     state->job = state->bs->job;
 }
 
-static void drive_backup_abort(BlkTransactionState *common)
+static void drive_backup_abort(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
     BlockDriverState *bs = state->bs;
@@ -1629,7 +1643,7 @@ static void drive_backup_abort(BlkTransactionState *common)
     }
 }
 
-static void drive_backup_clean(BlkTransactionState *common)
+static void drive_backup_clean(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
 
@@ -1639,13 +1653,13 @@ static void drive_backup_clean(BlkTransactionState *common)
 }
 
 typedef struct BlockdevBackupState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     BlockJob *job;
     AioContext *aio_context;
 } BlockdevBackupState;
 
-static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
+static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockdevBackup *backup;
@@ -1694,7 +1708,7 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
     state->job = state->bs->job;
 }
 
-static void blockdev_backup_abort(BlkTransactionState *common)
+static void blockdev_backup_abort(BlkActionState *common)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockDriverState *bs = state->bs;
@@ -1705,7 +1719,7 @@ static void blockdev_backup_abort(BlkTransactionState *common)
     }
 }
 
-static void blockdev_backup_clean(BlkTransactionState *common)
+static void blockdev_backup_clean(BlkActionState *common)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
 
@@ -1715,7 +1729,7 @@ static void blockdev_backup_clean(BlkTransactionState *common)
 }
 
 typedef struct BlockDirtyBitmapState {
-    BlkTransactionState common;
+    BlkActionState common;
     BdrvDirtyBitmap *bitmap;
     BlockDriverState *bs;
     AioContext *aio_context;
@@ -1723,7 +1737,7 @@ typedef struct BlockDirtyBitmapState {
     bool prepared;
 } BlockDirtyBitmapState;
 
-static void block_dirty_bitmap_add_prepare(BlkTransactionState *common,
+static void block_dirty_bitmap_add_prepare(BlkActionState *common,
                                            Error **errp)
 {
     Error *local_err = NULL;
@@ -1744,7 +1758,7 @@ static void block_dirty_bitmap_add_prepare(BlkTransactionState *common,
     }
 }
 
-static void block_dirty_bitmap_add_abort(BlkTransactionState *common)
+static void block_dirty_bitmap_add_abort(BlkActionState *common)
 {
     BlockDirtyBitmapAdd *action;
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
@@ -1759,7 +1773,7 @@ static void block_dirty_bitmap_add_abort(BlkTransactionState *common)
     }
 }
 
-static void block_dirty_bitmap_clear_prepare(BlkTransactionState *common,
+static void block_dirty_bitmap_clear_prepare(BlkActionState *common,
                                              Error **errp)
 {
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
@@ -1788,7 +1802,7 @@ static void block_dirty_bitmap_clear_prepare(BlkTransactionState *common,
     /* AioContext is released in .clean() */
 }
 
-static void block_dirty_bitmap_clear_abort(BlkTransactionState *common)
+static void block_dirty_bitmap_clear_abort(BlkActionState *common)
 {
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
                                              common, common);
@@ -1796,7 +1810,7 @@ static void block_dirty_bitmap_clear_abort(BlkTransactionState *common)
     bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
 }
 
-static void block_dirty_bitmap_clear_commit(BlkTransactionState *common)
+static void block_dirty_bitmap_clear_commit(BlkActionState *common)
 {
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
                                              common, common);
@@ -1804,7 +1818,7 @@ static void block_dirty_bitmap_clear_commit(BlkTransactionState *common)
     hbitmap_free(state->backup);
 }
 
-static void block_dirty_bitmap_clear_clean(BlkTransactionState *common)
+static void block_dirty_bitmap_clear_clean(BlkActionState *common)
 {
     BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
                                              common, common);
@@ -1814,17 +1828,17 @@ static void block_dirty_bitmap_clear_clean(BlkTransactionState *common)
     }
 }
 
-static void abort_prepare(BlkTransactionState *common, Error **errp)
+static void abort_prepare(BlkActionState *common, Error **errp)
 {
     error_setg(errp, "Transaction aborted using Abort action");
 }
 
-static void abort_commit(BlkTransactionState *common)
+static void abort_commit(BlkActionState *common)
 {
     g_assert_not_reached(); /* this action never succeeds */
 }
 
-static const BdrvActionOps actions[] = {
+static const BlkActionOps actions[] = {
     [TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC] = {
         .instance_size = sizeof(ExternalSnapshotState),
         .prepare  = external_snapshot_prepare,
@@ -1844,7 +1858,7 @@ static const BdrvActionOps actions[] = {
         .clean = blockdev_backup_clean,
     },
     [TRANSACTION_ACTION_KIND_ABORT] = {
-        .instance_size = sizeof(BlkTransactionState),
+        .instance_size = sizeof(BlkActionState),
         .prepare = abort_prepare,
         .commit = abort_commit,
     },
@@ -1875,10 +1889,10 @@ static const BdrvActionOps actions[] = {
 void qmp_transaction(TransactionActionList *dev_list, Error **errp)
 {
     TransactionActionList *dev_entry = dev_list;
-    BlkTransactionState *state, *next;
+    BlkActionState *state, *next;
     Error *local_err = NULL;
 
-    QSIMPLEQ_HEAD(snap_bdrv_states, BlkTransactionState) snap_bdrv_states;
+    QSIMPLEQ_HEAD(snap_bdrv_states, BlkActionState) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
 
     /* drain all i/o before any operations */
@@ -1887,7 +1901,7 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
     /* We don't do anything in this loop that commits us to the operations */
     while (NULL != dev_entry) {
         TransactionAction *dev_info = NULL;
-        const BdrvActionOps *ops;
+        const BlkActionOps *ops;
 
         dev_info = dev_entry->value;
         dev_entry = dev_entry->next;
-- 
2.4.3

[Qemu-devel] [PATCH v5 04/14] backup: Extract dirty bitmap handling as a separate function

[Fam Zheng]

This will be reused by the coming new transactional completion code.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
 block/backup.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index 965654d..9776d9c 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -210,6 +210,21 @@ static void backup_iostatus_reset(BlockJob *job)
 
     bdrv_iostatus_reset(s->target);
 }
+static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
+{
+    BdrvDirtyBitmap *bm;
+    BlockDriverState *bs = job->common.bs;
+
+    if (ret < 0 || block_job_is_cancelled(&job->common)) {
+        /* Merge the successor back into the parent, delete nothing. */
+        bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
+        assert(bm);
+    } else {
+        /* Everything is fine, delete this bitmap and install the backup. */
+        bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL);
+        assert(bm);
+    }
+}
 
 static const BlockJobDriver backup_job_driver = {
     .instance_size  = sizeof(BackupBlockJob),
@@ -430,16 +445,7 @@ static void coroutine_fn backup_run(void *opaque)
     qemu_co_rwlock_unlock(&job->flush_rwlock);
 
     if (job->sync_bitmap) {
-        BdrvDirtyBitmap *bm;
-        if (ret < 0 || block_job_is_cancelled(&job->common)) {
-            /* Merge the successor back into the parent, delete nothing. */
-            bm = bdrv_reclaim_dirty_bitmap(bs, job->sync_bitmap, NULL);
-            assert(bm);
-        } else {
-            /* Everything is fine, delete this bitmap and install the backup. */
-            bm = bdrv_dirty_bitmap_abdicate(bs, job->sync_bitmap, NULL);
-            assert(bm);
-        }
+        backup_cleanup_sync_bitmap(job, ret);
     }
     hbitmap_free(job->bitmap);
 
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 04/14] backup: Extract dirty bitmap handling as a separate function

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 366 bytes --]

On 07.09.2015 09:34, Fam Zheng wrote:
> This will be reused by the coming new transactional completion code.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> ---
>  block/backup.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)

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


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Re: [Qemu-devel] [PATCH v5 04/14] backup: Extract dirty bitmap handling as a separate function

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 796 bytes --]

On 09/07/2015 01:34 AM, Fam Zheng wrote:
> This will be reused by the coming new transactional completion code.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> ---
>  block/backup.c | 26 ++++++++++++++++----------
>  1 file changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index 965654d..9776d9c 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -210,6 +210,21 @@ static void backup_iostatus_reset(BlockJob *job)
>  
>      bdrv_iostatus_reset(s->target);
>  }
> +static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)

Blank lines between functions?

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


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Re: [Qemu-devel] [PATCH v5 04/14] backup: Extract dirty bitmap handling as a separate function

[Fam Zheng]

On Fri, 09/11 13:35, Eric Blake wrote:
> On 09/07/2015 01:34 AM, Fam Zheng wrote:
> > This will be reused by the coming new transactional completion code.
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > Reviewed-by: John Snow <jsnow@redhat.com>
> > ---
> >  block/backup.c | 26 ++++++++++++++++----------
> >  1 file changed, 16 insertions(+), 10 deletions(-)
> > 
> > diff --git a/block/backup.c b/block/backup.c
> > index 965654d..9776d9c 100644
> > --- a/block/backup.c
> > +++ b/block/backup.c
> > @@ -210,6 +210,21 @@ static void backup_iostatus_reset(BlockJob *job)
> >  
> >      bdrv_iostatus_reset(s->target);
> >  }
> > +static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
> 
> Blank lines between functions?
>

OK, will add one!

Fam

[Qemu-devel] [PATCH v5 05/14] blockjob: Introduce reference count

[Fam Zheng]

So that block_job_complete_sync can be simplified.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/mirror.c           |  2 +-
 blockjob.c               | 22 ++++++++++++++--------
 include/block/blockjob.h | 18 +++++++++++++++---
 3 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index a258926..3472ad4 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -736,7 +736,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
     s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
     if (!s->dirty_bitmap) {
         g_free(s->replaces);
-        block_job_release(bs);
+        block_job_unref(&s->common);
         return;
     }
     bdrv_set_enable_write_cache(s->target, true);
diff --git a/blockjob.c b/blockjob.c
index 62bb906..ec12887 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -58,6 +58,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     job->cb            = cb;
     job->opaque        = opaque;
     job->busy          = true;
+    job->refcnt        = 1;
     bs->job = job;
 
     /* Only set speed when necessary to avoid NotSupported error */
@@ -66,7 +67,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
 
         block_job_set_speed(job, speed, &local_err);
         if (local_err) {
-            block_job_release(bs);
+            block_job_unref(job);
             error_propagate(errp, local_err);
             return NULL;
         }
@@ -74,14 +75,19 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
     return job;
 }
 
-void block_job_release(BlockDriverState *bs)
+void block_job_ref(BlockJob *job)
 {
-    BlockJob *job = bs->job;
+    ++job->refcnt;
+}
 
-    bs->job = NULL;
-    bdrv_op_unblock_all(bs, job->blocker);
-    error_free(job->blocker);
-    g_free(job);
+void block_job_unref(BlockJob *job)
+{
+    if (--job->refcnt == 0) {
+        job->bs->job = NULL;
+        bdrv_op_unblock_all(job->bs, job->blocker);
+        error_free(job->blocker);
+        g_free(job);
+    }
 }
 
 void block_job_completed(BlockJob *job, int ret)
@@ -90,7 +96,7 @@ void block_job_completed(BlockJob *job, int ret)
 
     assert(bs->job == job);
     job->cb(job->opaque, ret);
-    block_job_release(bs);
+    block_job_unref(job);
 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index dd9d5e6..3e7ad21 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -122,6 +122,9 @@ struct BlockJob {
 
     /** The opaque value that is passed to the completion function.  */
     void *opaque;
+
+    /** Reference count of the block job */
+    int refcnt;
 };
 
 /**
@@ -166,12 +169,21 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
 void block_job_yield(BlockJob *job);
 
 /**
- * block_job_release:
+ * block_job_ref:
  * @bs: The block device.
  *
- * Release job resources when an error occurred or job completed.
+ * Grab a reference to the block job. Should be paired with block_job_unref.
  */
-void block_job_release(BlockDriverState *bs);
+void block_job_ref(BlockJob *job);
+
+/**
+ * block_job_unref:
+ * @bs: The block device.
+ *
+ * Release reference to the block job and release resources if it is the last
+ * reference.
+ */
+void block_job_unref(BlockJob *job);
 
 /**
  * block_job_completed:
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 05/14] blockjob: Introduce reference count

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 400 bytes --]

On 07.09.2015 09:34, Fam Zheng wrote:
> So that block_job_complete_sync can be simplified.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/mirror.c           |  2 +-
>  blockjob.c               | 22 ++++++++++++++--------
>  include/block/blockjob.h | 18 +++++++++++++++---
>  3 files changed, 30 insertions(+), 12 deletions(-)

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


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[Qemu-devel] [PATCH v5 06/14] blockjob: Add .commit and .abort block job actions

[Fam Zheng]

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 include/block/blockjob.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 3e7ad21..a7b497c 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -50,6 +50,24 @@ typedef struct BlockJobDriver {
      * manually.
      */
     void (*complete)(BlockJob *job, Error **errp);
+
+    /**
+     * If the callback is not NULL, it will be invoked when all the jobs
+     * belonging to the same transaction complete; or upon this job's
+     * completion if it is not in a transaction. Skipped if NULL.
+     *
+     * Exactly one of .commit() and .abort() will be called for each job.
+     */
+    void (*commit)(BlockJob *job);
+
+    /**
+     * If the callback is not NULL, it will be invoked when any job in the
+     * same transaction fails; or upon this job's failure (due to error or
+     * cancellation) if it is not in a transaction. Skipped if NULL.
+     *
+     * Exactly one of .commit() and .abort() will be called for each job.
+     */
+    void (*abort)(BlockJob *job);
 } BlockJobDriver;
 
 /**
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 06/14] blockjob: Add .commit and .abort block job actions

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 230 bytes --]

On 07.09.2015 09:34, Fam Zheng wrote:
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  include/block/blockjob.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)

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


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[Qemu-devel] [PATCH v5 07/14] blockjob: Add "completed" and "ret" in BlockJob

[Fam Zheng]

They are set when block_job_completed is called.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
 blockjob.c               | 3 +++
 include/block/blockjob.h | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/blockjob.c b/blockjob.c
index ec12887..293b62a 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -95,6 +95,9 @@ void block_job_completed(BlockJob *job, int ret)
     BlockDriverState *bs = job->bs;
 
     assert(bs->job == job);
+    assert(!job->completed);
+    job->completed = true;
+    job->ret = ret;
     job->cb(job->opaque, ret);
     block_job_unref(job);
 }
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index a7b497c..f6e4c86 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -143,6 +143,15 @@ struct BlockJob {
 
     /** Reference count of the block job */
     int refcnt;
+
+    /* True if this job has reported completion by calling block_job_completed.
+     */
+    bool completed;
+
+    /* ret code passed to block_job_completed.
+     */
+    int ret;
+
 };
 
 /**
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 07/14] blockjob: Add "completed" and "ret" in BlockJob

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 359 bytes --]

On 07.09.2015 09:34, Fam Zheng wrote:
> They are set when block_job_completed is called.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> ---
>  blockjob.c               | 3 +++
>  include/block/blockjob.h | 9 +++++++++
>  2 files changed, 12 insertions(+)

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


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[Qemu-devel] [PATCH v5 08/14] blockjob: Simplify block_job_finish_sync

[Fam Zheng]

With job->completed and job->ret to replace BlockFinishData.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockjob.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 293b62a..36c18e0 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -185,43 +185,28 @@ struct BlockFinishData {
     int ret;
 };
 
-static void block_job_finish_cb(void *opaque, int ret)
-{
-    struct BlockFinishData *data = opaque;
-
-    data->cancelled = block_job_is_cancelled(data->job);
-    data->ret = ret;
-    data->cb(data->opaque, ret);
-}
-
 static int block_job_finish_sync(BlockJob *job,
                                  void (*finish)(BlockJob *, Error **errp),
                                  Error **errp)
 {
-    struct BlockFinishData data;
     BlockDriverState *bs = job->bs;
     Error *local_err = NULL;
+    int ret;
 
     assert(bs->job == job);
 
-    /* Set up our own callback to store the result and chain to
-     * the original callback.
-     */
-    data.job = job;
-    data.cb = job->cb;
-    data.opaque = job->opaque;
-    data.ret = -EINPROGRESS;
-    job->cb = block_job_finish_cb;
-    job->opaque = &data;
+    block_job_ref(job);
     finish(job, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return -EBUSY;
     }
-    while (data.ret == -EINPROGRESS) {
+    while (!job->completed) {
         aio_poll(bdrv_get_aio_context(bs), true);
     }
-    return (data.cancelled && data.ret == 0) ? -ECANCELED : data.ret;
+    ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
+    block_job_unref(job);
+    return ret;
 }
 
 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 08/14] blockjob: Simplify block_job_finish_sync

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 309 bytes --]

On 07.09.2015 09:34, Fam Zheng wrote:
> With job->completed and job->ret to replace BlockFinishData.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockjob.c | 27 ++++++---------------------
>  1 file changed, 6 insertions(+), 21 deletions(-)

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


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[Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Fam Zheng]

Sometimes block jobs must execute as a transaction group.  Finishing
jobs wait until all other jobs are ready to complete successfully.
Failure or cancellation of one job cancels the other jobs in the group.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
[Rewrite the implementation which is now contained in block_job_completed.
--Fam]
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
 include/block/block.h    |   1 +
 include/block/blockjob.h |  38 ++++++++++++++
 3 files changed, 171 insertions(+), 2 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 36c18e0..1b4eb20 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -36,6 +36,19 @@
 #include "qemu/timer.h"
 #include "qapi-event.h"
 
+/* Transactional group of block jobs */
+struct BlockJobTxn {
+
+    /* Is this txn being cancelled? */
+    bool aborting;
+
+    /* List of jobs */
+    QLIST_HEAD(, BlockJob) jobs;
+
+    /* Reference count */
+    int refcnt;
+};
+
 void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
                        int64_t speed, BlockCompletionFunc *cb,
                        void *opaque, Error **errp)
@@ -90,6 +103,85 @@ void block_job_unref(BlockJob *job)
     }
 }
 
+static void block_job_completed_single(BlockJob *job)
+{
+    if (!job->ret) {
+        if (job->driver->commit) {
+            job->driver->commit(job);
+        }
+    } else {
+        if (job->driver->abort) {
+            job->driver->abort(job);
+        }
+    }
+    job->cb(job->opaque, job->ret);
+    block_job_unref(job);
+}
+
+static void block_job_completed_txn_abort(BlockJob *job)
+{
+    AioContext *ctx;
+    BlockJobTxn *txn = job->txn;
+    BlockJob *other_job, *next;
+
+    if (txn->aborting) {
+        /*
+         * We are cancelled by another job, which will handle everything.
+         */
+        return;
+    }
+    txn->aborting = true;
+    /* We are the first failed job. Cancel other jobs. */
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        ctx = bdrv_get_aio_context(other_job->bs);
+        aio_context_acquire(ctx);
+    }
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        if (other_job == job || other_job->completed) {
+            /* Other jobs are "effectively" cancelled by us, set the status for
+             * them; this job, however, may or may not be cancelled, depending
+             * on the caller, so leave it. */
+            if (other_job != job) {
+                other_job->cancelled = true;
+            }
+            continue;
+        }
+        block_job_cancel_sync(other_job);
+        assert(other_job->completed);
+    }
+    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+        ctx = bdrv_get_aio_context(other_job->bs);
+        block_job_completed_single(other_job);
+        aio_context_release(ctx);
+    }
+    block_job_txn_unref(txn);
+}
+
+static void block_job_completed_txn_success(BlockJob *job)
+{
+    AioContext *ctx;
+    BlockJobTxn *txn = job->txn;
+    BlockJob *other_job, *next;
+    /*
+     * Successful completion, see if there are other running jobs in this
+     * txn.
+     **/
+    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
+        if (!other_job->completed) {
+            return;
+        }
+    }
+    /* We are the last completed job, commit the transaction. */
+    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+        ctx = bdrv_get_aio_context(other_job->bs);
+        aio_context_acquire(ctx);
+        assert(other_job->ret == 0);
+        block_job_completed_single(other_job);
+        aio_context_release(ctx);
+    }
+    block_job_txn_unref(txn);
+}
+
 void block_job_completed(BlockJob *job, int ret)
 {
     BlockDriverState *bs = job->bs;
@@ -98,8 +190,13 @@ void block_job_completed(BlockJob *job, int ret)
     assert(!job->completed);
     job->completed = true;
     job->ret = ret;
-    job->cb(job->opaque, ret);
-    block_job_unref(job);
+    if (!job->txn) {
+        block_job_completed_single(job);
+    } else if (ret < 0 || block_job_is_cancelled(job)) {
+        block_job_completed_txn_abort(job);
+    } else {
+        block_job_completed_txn_success(job);
+    }
 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
@@ -398,3 +495,36 @@ void block_job_defer_to_main_loop(BlockJob *job,
 
     qemu_bh_schedule(data->bh);
 }
+
+BlockJobTxn *block_job_txn_new(void)
+{
+    BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
+    QLIST_INIT(&txn->jobs);
+    txn->refcnt = 1;
+    return txn;
+}
+
+static void block_job_txn_ref(BlockJobTxn *txn)
+{
+    txn->refcnt++;
+}
+
+void block_job_txn_unref(BlockJobTxn *txn)
+{
+    if (--txn->refcnt == 0) {
+        g_free(txn);
+    }
+}
+
+void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
+{
+    if (!txn) {
+        return;
+    }
+
+    assert(!job->txn);
+    job->txn = txn;
+
+    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
+    block_job_txn_ref(txn);
+}
diff --git a/include/block/block.h b/include/block/block.h
index e619b99..f80d984 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -14,6 +14,7 @@ typedef struct BlockDriver BlockDriver;
 typedef struct BlockJob BlockJob;
 typedef struct BdrvChild BdrvChild;
 typedef struct BdrvChildRole BdrvChildRole;
+typedef struct BlockJobTxn BlockJobTxn;
 
 typedef struct BlockDriverInfo {
     /* in bytes, 0 if irrelevant */
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index f6e4c86..0a6c138 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -152,6 +152,9 @@ struct BlockJob {
      */
     int ret;
 
+    /** Non-NULL if this job is part of a transaction */
+    BlockJobTxn *txn;
+    QLIST_ENTRY(BlockJob) txn_list;
 };
 
 /**
@@ -395,4 +398,39 @@ void block_job_defer_to_main_loop(BlockJob *job,
                                   BlockJobDeferToMainLoopFn *fn,
                                   void *opaque);
 
+/**
+ * block_job_txn_new:
+ *
+ * Allocate and return a new block job transaction.  Jobs can be added to the
+ * transaction using block_job_txn_add_job().
+ *
+ * The transaction is automatically freed when the last job completes or is
+ * cancelled.
+ *
+ * All jobs in the transaction either complete successfully or fail/cancel as a
+ * group.  Jobs wait for each other before completing.  Cancelling one job
+ * cancels all jobs in the transaction.
+ */
+BlockJobTxn *block_job_txn_new(void);
+
+/**
+ * block_job_txn_unref:
+ *
+ * Release a reference that was previously acquired with block_job_txn_add_job
+ * or block_job_txn_new. If it's the last reference to the object, it will be
+ * freed.
+ */
+void block_job_txn_unref(BlockJobTxn *txn);
+
+/**
+ * block_job_txn_add_job:
+ * @txn: The transaction (may be NULL)
+ * @job: Job to add to the transaction
+ *
+ * Add @job to the transaction.  The @job must not already be in a transaction.
+ * The block job driver must call block_job_txn_prepare_to_complete() before
+ * final cleanup and completion.
+ */
+void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
+
 #endif
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Max Reitz]

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On 07.09.2015 09:34, Fam Zheng wrote:
> Sometimes block jobs must execute as a transaction group.  Finishing
> jobs wait until all other jobs are ready to complete successfully.
> Failure or cancellation of one job cancels the other jobs in the group.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> [Rewrite the implementation which is now contained in block_job_completed.
> --Fam]
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/block/block.h    |   1 +
>  include/block/blockjob.h |  38 ++++++++++++++
>  3 files changed, 171 insertions(+), 2 deletions(-)
> 

[snip]

> diff --git a/include/block/block.h b/include/block/block.h
> index e619b99..f80d984 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h

[snip]

> @@ -395,4 +398,39 @@ void block_job_defer_to_main_loop(BlockJob *job,
>                                    BlockJobDeferToMainLoopFn *fn,
>                                    void *opaque);
>  
> +/**
> + * block_job_txn_new:
> + *
> + * Allocate and return a new block job transaction.  Jobs can be added to the
> + * transaction using block_job_txn_add_job().
> + *
> + * The transaction is automatically freed when the last job completes or is
> + * cancelled.
> + *
> + * All jobs in the transaction either complete successfully or fail/cancel as a
> + * group.  Jobs wait for each other before completing.  Cancelling one job
> + * cancels all jobs in the transaction.
> + */
> +BlockJobTxn *block_job_txn_new(void);
> +
> +/**
> + * block_job_txn_unref:
> + *
> + * Release a reference that was previously acquired with block_job_txn_add_job
> + * or block_job_txn_new. If it's the last reference to the object, it will be
> + * freed.
> + */
> +void block_job_txn_unref(BlockJobTxn *txn);
> +
> +/**
> + * block_job_txn_add_job:
> + * @txn: The transaction (may be NULL)
> + * @job: Job to add to the transaction
> + *
> + * Add @job to the transaction.  The @job must not already be in a transaction.
> + * The block job driver must call block_job_txn_prepare_to_complete() before
> + * final cleanup and completion.

This comment still needs a fixup (block_job_txn_prepare_to_complete()
does not exist).

Looks good other than that.

Max

> + */
> +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
> +
>  #endif
> 



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Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Max Reitz]

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On 07.09.2015 09:34, Fam Zheng wrote:
> Sometimes block jobs must execute as a transaction group.  Finishing
> jobs wait until all other jobs are ready to complete successfully.
> Failure or cancellation of one job cancels the other jobs in the group.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> [Rewrite the implementation which is now contained in block_job_completed.
> --Fam]
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/block/block.h    |   1 +
>  include/block/blockjob.h |  38 ++++++++++++++
>  3 files changed, 171 insertions(+), 2 deletions(-)
> 
> diff --git a/blockjob.c b/blockjob.c
> index 36c18e0..1b4eb20 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -36,6 +36,19 @@
>  #include "qemu/timer.h"
>  #include "qapi-event.h"
>  
> +/* Transactional group of block jobs */
> +struct BlockJobTxn {
> +
> +    /* Is this txn being cancelled? */
> +    bool aborting;
> +
> +    /* List of jobs */
> +    QLIST_HEAD(, BlockJob) jobs;
> +
> +    /* Reference count */
> +    int refcnt;
> +};
> +
>  void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
>                         int64_t speed, BlockCompletionFunc *cb,
>                         void *opaque, Error **errp)
> @@ -90,6 +103,85 @@ void block_job_unref(BlockJob *job)
>      }
>  }
>  
> +static void block_job_completed_single(BlockJob *job)
> +{
> +    if (!job->ret) {
> +        if (job->driver->commit) {
> +            job->driver->commit(job);
> +        }
> +    } else {
> +        if (job->driver->abort) {
> +            job->driver->abort(job);
> +        }
> +    }
> +    job->cb(job->opaque, job->ret);
> +    block_job_unref(job);
> +}
> +
> +static void block_job_completed_txn_abort(BlockJob *job)
> +{
> +    AioContext *ctx;
> +    BlockJobTxn *txn = job->txn;
> +    BlockJob *other_job, *next;
> +
> +    if (txn->aborting) {
> +        /*
> +         * We are cancelled by another job, which will handle everything.
> +         */

After having reviewed patch 11, I think we need to call
block_job_txn_unref(txn) here.

> +        return;
> +    }
> +    txn->aborting = true;
> +    /* We are the first failed job. Cancel other jobs. */
> +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> +        ctx = bdrv_get_aio_context(other_job->bs);
> +        aio_context_acquire(ctx);
> +    }
> +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> +        if (other_job == job || other_job->completed) {
> +            /* Other jobs are "effectively" cancelled by us, set the status for
> +             * them; this job, however, may or may not be cancelled, depending
> +             * on the caller, so leave it. */
> +            if (other_job != job) {
> +                other_job->cancelled = true;
> +            }
> +            continue;
> +        }
> +        block_job_cancel_sync(other_job);
> +        assert(other_job->completed);
> +    }
> +    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> +        ctx = bdrv_get_aio_context(other_job->bs);
> +        block_job_completed_single(other_job);
> +        aio_context_release(ctx);
> +    }
> +    block_job_txn_unref(txn);
> +}
> +
> +static void block_job_completed_txn_success(BlockJob *job)
> +{
> +    AioContext *ctx;
> +    BlockJobTxn *txn = job->txn;
> +    BlockJob *other_job, *next;
> +    /*
> +     * Successful completion, see if there are other running jobs in this
> +     * txn.
> +     **/
> +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> +        if (!other_job->completed) {

Same here.

Max

> +            return;
> +        }
> +    }
> +    /* We are the last completed job, commit the transaction. */
> +    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> +        ctx = bdrv_get_aio_context(other_job->bs);
> +        aio_context_acquire(ctx);
> +        assert(other_job->ret == 0);
> +        block_job_completed_single(other_job);
> +        aio_context_release(ctx);
> +    }
> +    block_job_txn_unref(txn);
> +}
> +
>  void block_job_completed(BlockJob *job, int ret)
>  {
>      BlockDriverState *bs = job->bs;
> @@ -98,8 +190,13 @@ void block_job_completed(BlockJob *job, int ret)
>      assert(!job->completed);
>      job->completed = true;
>      job->ret = ret;
> -    job->cb(job->opaque, ret);
> -    block_job_unref(job);
> +    if (!job->txn) {
> +        block_job_completed_single(job);
> +    } else if (ret < 0 || block_job_is_cancelled(job)) {
> +        block_job_completed_txn_abort(job);
> +    } else {
> +        block_job_completed_txn_success(job);
> +    }
>  }
>  
>  void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
> @@ -398,3 +495,36 @@ void block_job_defer_to_main_loop(BlockJob *job,
>  
>      qemu_bh_schedule(data->bh);
>  }
> +
> +BlockJobTxn *block_job_txn_new(void)
> +{
> +    BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
> +    QLIST_INIT(&txn->jobs);
> +    txn->refcnt = 1;
> +    return txn;
> +}
> +
> +static void block_job_txn_ref(BlockJobTxn *txn)
> +{
> +    txn->refcnt++;
> +}
> +
> +void block_job_txn_unref(BlockJobTxn *txn)
> +{
> +    if (--txn->refcnt == 0) {
> +        g_free(txn);
> +    }
> +}
> +
> +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
> +{
> +    if (!txn) {
> +        return;
> +    }
> +
> +    assert(!job->txn);
> +    job->txn = txn;
> +
> +    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
> +    block_job_txn_ref(txn);
> +}
> diff --git a/include/block/block.h b/include/block/block.h
> index e619b99..f80d984 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -14,6 +14,7 @@ typedef struct BlockDriver BlockDriver;
>  typedef struct BlockJob BlockJob;
>  typedef struct BdrvChild BdrvChild;
>  typedef struct BdrvChildRole BdrvChildRole;
> +typedef struct BlockJobTxn BlockJobTxn;
>  
>  typedef struct BlockDriverInfo {
>      /* in bytes, 0 if irrelevant */
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index f6e4c86..0a6c138 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -152,6 +152,9 @@ struct BlockJob {
>       */
>      int ret;
>  
> +    /** Non-NULL if this job is part of a transaction */
> +    BlockJobTxn *txn;
> +    QLIST_ENTRY(BlockJob) txn_list;
>  };
>  
>  /**
> @@ -395,4 +398,39 @@ void block_job_defer_to_main_loop(BlockJob *job,
>                                    BlockJobDeferToMainLoopFn *fn,
>                                    void *opaque);
>  
> +/**
> + * block_job_txn_new:
> + *
> + * Allocate and return a new block job transaction.  Jobs can be added to the
> + * transaction using block_job_txn_add_job().
> + *
> + * The transaction is automatically freed when the last job completes or is
> + * cancelled.
> + *
> + * All jobs in the transaction either complete successfully or fail/cancel as a
> + * group.  Jobs wait for each other before completing.  Cancelling one job
> + * cancels all jobs in the transaction.
> + */
> +BlockJobTxn *block_job_txn_new(void);
> +
> +/**
> + * block_job_txn_unref:
> + *
> + * Release a reference that was previously acquired with block_job_txn_add_job
> + * or block_job_txn_new. If it's the last reference to the object, it will be
> + * freed.
> + */
> +void block_job_txn_unref(BlockJobTxn *txn);
> +
> +/**
> + * block_job_txn_add_job:
> + * @txn: The transaction (may be NULL)
> + * @job: Job to add to the transaction
> + *
> + * Add @job to the transaction.  The @job must not already be in a transaction.
> + * The block job driver must call block_job_txn_prepare_to_complete() before
> + * final cleanup and completion.
> + */
> +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
> +
>  #endif
> 



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Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Fam Zheng]

On Fri, 09/11 20:52, Max Reitz wrote:
> On 07.09.2015 09:34, Fam Zheng wrote:
> > Sometimes block jobs must execute as a transaction group.  Finishing
> > jobs wait until all other jobs are ready to complete successfully.
> > Failure or cancellation of one job cancels the other jobs in the group.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > [Rewrite the implementation which is now contained in block_job_completed.
> > --Fam]
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
> >  include/block/block.h    |   1 +
> >  include/block/blockjob.h |  38 ++++++++++++++
> >  3 files changed, 171 insertions(+), 2 deletions(-)
> > 
> > diff --git a/blockjob.c b/blockjob.c
> > index 36c18e0..1b4eb20 100644
> > --- a/blockjob.c
> > +++ b/blockjob.c
> > @@ -36,6 +36,19 @@
> >  #include "qemu/timer.h"
> >  #include "qapi-event.h"
> >  
> > +/* Transactional group of block jobs */
> > +struct BlockJobTxn {
> > +
> > +    /* Is this txn being cancelled? */
> > +    bool aborting;
> > +
> > +    /* List of jobs */
> > +    QLIST_HEAD(, BlockJob) jobs;
> > +
> > +    /* Reference count */
> > +    int refcnt;
> > +};
> > +
> >  void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
> >                         int64_t speed, BlockCompletionFunc *cb,
> >                         void *opaque, Error **errp)
> > @@ -90,6 +103,85 @@ void block_job_unref(BlockJob *job)
> >      }
> >  }
> >  
> > +static void block_job_completed_single(BlockJob *job)
> > +{
> > +    if (!job->ret) {
> > +        if (job->driver->commit) {
> > +            job->driver->commit(job);
> > +        }
> > +    } else {
> > +        if (job->driver->abort) {
> > +            job->driver->abort(job);
> > +        }
> > +    }
> > +    job->cb(job->opaque, job->ret);
> > +    block_job_unref(job);
> > +}
> > +
> > +static void block_job_completed_txn_abort(BlockJob *job)
> > +{
> > +    AioContext *ctx;
> > +    BlockJobTxn *txn = job->txn;
> > +    BlockJob *other_job, *next;
> > +
> > +    if (txn->aborting) {
> > +        /*
> > +         * We are cancelled by another job, which will handle everything.
> > +         */
> 
> After having reviewed patch 11, I think we need to call
> block_job_txn_unref(txn) here.
> 
> > +        return;
> > +    }
> > +    txn->aborting = true;
> > +    /* We are the first failed job. Cancel other jobs. */
> > +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > +        ctx = bdrv_get_aio_context(other_job->bs);
> > +        aio_context_acquire(ctx);
> > +    }
> > +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > +        if (other_job == job || other_job->completed) {
> > +            /* Other jobs are "effectively" cancelled by us, set the status for
> > +             * them; this job, however, may or may not be cancelled, depending
> > +             * on the caller, so leave it. */
> > +            if (other_job != job) {
> > +                other_job->cancelled = true;
> > +            }
> > +            continue;
> > +        }
> > +        block_job_cancel_sync(other_job);
> > +        assert(other_job->completed);
> > +    }
> > +    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> > +        ctx = bdrv_get_aio_context(other_job->bs);
> > +        block_job_completed_single(other_job);
> > +        aio_context_release(ctx);
> > +    }
> > +    block_job_txn_unref(txn);
> > +}
> > +
> > +static void block_job_completed_txn_success(BlockJob *job)
> > +{
> > +    AioContext *ctx;
> > +    BlockJobTxn *txn = job->txn;
> > +    BlockJob *other_job, *next;
> > +    /*
> > +     * Successful completion, see if there are other running jobs in this
> > +     * txn.
> > +     **/
> > +    QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
> > +        if (!other_job->completed) {
> 
> Same here.

Yes. Will add at ...

> > +            return;
> > +        }
> > +    }
> > +    /* We are the last completed job, commit the transaction. */
> > +    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
> > +        ctx = bdrv_get_aio_context(other_job->bs);
> > +        aio_context_acquire(ctx);
> > +        assert(other_job->ret == 0);
> > +        block_job_completed_single(other_job);
> > +        aio_context_release(ctx);
> > +    }
> > +    block_job_txn_unref(txn);
> > +}
> > +
> >  void block_job_completed(BlockJob *job, int ret)
> >  {
> >      BlockDriverState *bs = job->bs;
> > @@ -98,8 +190,13 @@ void block_job_completed(BlockJob *job, int ret)
> >      assert(!job->completed);
> >      job->completed = true;
> >      job->ret = ret;
> > -    job->cb(job->opaque, ret);
> > -    block_job_unref(job);
> > +    if (!job->txn) {
> > +        block_job_completed_single(job);
> > +    } else if (ret < 0 || block_job_is_cancelled(job)) {
> > +        block_job_completed_txn_abort(job);
> > +    } else {
> > +        block_job_completed_txn_success(job);
> > +    }

Here in an "if (job->txn)" branch.

Fam

> >  }

Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Max Reitz]

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On 11.09.2015 20:52, Max Reitz wrote:
> On 07.09.2015 09:34, Fam Zheng wrote:
>> Sometimes block jobs must execute as a transaction group.  Finishing
>> jobs wait until all other jobs are ready to complete successfully.
>> Failure or cancellation of one job cancels the other jobs in the group.
>>
>> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>> [Rewrite the implementation which is now contained in block_job_completed.
>> --Fam]
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>> ---
>>  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
>>  include/block/block.h    |   1 +
>>  include/block/blockjob.h |  38 ++++++++++++++
>>  3 files changed, 171 insertions(+), 2 deletions(-)
>>

[...]

>> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
>> index f6e4c86..0a6c138 100644
>> --- a/include/block/blockjob.h
>> +++ b/include/block/blockjob.h

[...]

>> @@ -395,4 +398,39 @@ void block_job_defer_to_main_loop(BlockJob *job,

[...]

>> +
>> +/**
>> + * block_job_txn_add_job:
>> + * @txn: The transaction (may be NULL)
>> + * @job: Job to add to the transaction
>> + *
>> + * Add @job to the transaction.  The @job must not already be in a transaction.
>> + * The block job driver must call block_job_txn_prepare_to_complete() before
>> + * final cleanup and completion.

To me that sounds a bit as if this should be called e.g. in
block/backup.c:backup_complete(). Maybe add that this is called
automatically by block_job_completed()?

Either way:

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

>> + */
>> +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
>> +
>>  #endif


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Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Max Reitz]

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On 18.09.2015 13:09, Max Reitz wrote:
> On 11.09.2015 20:52, Max Reitz wrote:
>> On 07.09.2015 09:34, Fam Zheng wrote:
>>> Sometimes block jobs must execute as a transaction group.  Finishing
>>> jobs wait until all other jobs are ready to complete successfully.
>>> Failure or cancellation of one job cancels the other jobs in the group.
>>>
>>> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>>> [Rewrite the implementation which is now contained in block_job_completed.
>>> --Fam]
>>> Signed-off-by: Fam Zheng <famz@redhat.com>
>>> ---
>>>  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
>>>  include/block/block.h    |   1 +
>>>  include/block/blockjob.h |  38 ++++++++++++++
>>>  3 files changed, 171 insertions(+), 2 deletions(-)
>>>
> 
> [...]
> 
>>> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
>>> index f6e4c86..0a6c138 100644
>>> --- a/include/block/blockjob.h
>>> +++ b/include/block/blockjob.h
> 
> [...]
> 
>>> @@ -395,4 +398,39 @@ void block_job_defer_to_main_loop(BlockJob *job,
> 
> [...]
> 
>>> +
>>> +/**
>>> + * block_job_txn_add_job:
>>> + * @txn: The transaction (may be NULL)
>>> + * @job: Job to add to the transaction
>>> + *
>>> + * Add @job to the transaction.  The @job must not already be in a transaction.
>>> + * The block job driver must call block_job_txn_prepare_to_complete() before
>>> + * final cleanup and completion.
> 
> To me that sounds a bit as if this should be called e.g. in
> block/backup.c:backup_complete(). Maybe add that this is called
> automatically by block_job_completed()?
> 
> Either way:
> 
> Reviewed-by: Max Reitz <mreitz@redhat.com>

Oops, wrong version. And I didn't even read the comment again, which
would have showed that to me.

Please-ignore: Max Reitz <mreitz@redhat.com>

>>> + */
>>> +void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job);
>>> +
>>>  #endif
> 



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Re: [Qemu-devel] [PATCH v5 09/14] block: Add block job transactions

[Eric Blake]

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On 09/07/2015 01:34 AM, Fam Zheng wrote:
> Sometimes block jobs must execute as a transaction group.  Finishing
> jobs wait until all other jobs are ready to complete successfully.
> Failure or cancellation of one job cancels the other jobs in the group.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> [Rewrite the implementation which is now contained in block_job_completed.
> --Fam]
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockjob.c               | 134 ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/block/block.h    |   1 +
>  include/block/blockjob.h |  38 ++++++++++++++
>  3 files changed, 171 insertions(+), 2 deletions(-)

> +static void block_job_completed_txn_success(BlockJob *job)
> +{
> +    AioContext *ctx;
> +    BlockJobTxn *txn = job->txn;
> +    BlockJob *other_job, *next;
> +    /*
> +     * Successful completion, see if there are other running jobs in this
> +     * txn.
> +     **/

Unusual **/


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


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[Qemu-devel] [PATCH v5 10/14] blockdev: make BlockJobTxn available to qmp 'transaction'

[Fam Zheng]

From: Stefan Hajnoczi <stefanha@redhat.com>

Provide a BlockJobTxn to actions executed in a qmp 'transaction'
command.  This allows actions to make their block jobs either complete
as a group or fail/cancel together.

The next patch adds the first user.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockdev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 4ebded8..3d5e5cd 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1285,6 +1285,7 @@ typedef struct BlkActionOps {
 struct BlkActionState {
     TransactionAction *action;
     const BlkActionOps *ops;
+    BlockJobTxn *block_job_txn;
     QSIMPLEQ_ENTRY(BlkActionState) entry;
 };
 
@@ -1889,12 +1890,15 @@ static const BlkActionOps actions[] = {
 void qmp_transaction(TransactionActionList *dev_list, Error **errp)
 {
     TransactionActionList *dev_entry = dev_list;
+    BlockJobTxn *block_job_txn;
     BlkActionState *state, *next;
     Error *local_err = NULL;
 
     QSIMPLEQ_HEAD(snap_bdrv_states, BlkActionState) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
 
+    block_job_txn = block_job_txn_new();
+
     /* drain all i/o before any operations */
     bdrv_drain_all();
 
@@ -1914,6 +1918,7 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
         state = g_malloc0(ops->instance_size);
         state->ops = ops;
         state->action = dev_info;
+        state->block_job_txn = block_job_txn;
         QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, state, entry);
 
         state->ops->prepare(state, &local_err);
@@ -1940,6 +1945,7 @@ delete_and_fail:
         }
     }
 exit:
+    block_job_txn_unref(block_job_txn);
     QSIMPLEQ_FOREACH_SAFE(state, &snap_bdrv_states, entry, next) {
         if (state->ops->clean) {
             state->ops->clean(state);
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 10/14] blockdev: make BlockJobTxn available to qmp 'transaction'

[Max Reitz]

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On 07.09.2015 09:34, Fam Zheng wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
> 
> Provide a BlockJobTxn to actions executed in a qmp 'transaction'
> command.  This allows actions to make their block jobs either complete
> as a group or fail/cancel together.
> 
> The next patch adds the first user.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>

You can vouch for yourself, but can you vouch for John being fine with
the change from v4? ;-)

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  blockdev.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 4ebded8..3d5e5cd 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1285,6 +1285,7 @@ typedef struct BlkActionOps {
>  struct BlkActionState {
>      TransactionAction *action;
>      const BlkActionOps *ops;
> +    BlockJobTxn *block_job_txn;
>      QSIMPLEQ_ENTRY(BlkActionState) entry;
>  };
>  
> @@ -1889,12 +1890,15 @@ static const BlkActionOps actions[] = {
>  void qmp_transaction(TransactionActionList *dev_list, Error **errp)
>  {
>      TransactionActionList *dev_entry = dev_list;
> +    BlockJobTxn *block_job_txn;
>      BlkActionState *state, *next;
>      Error *local_err = NULL;
>  
>      QSIMPLEQ_HEAD(snap_bdrv_states, BlkActionState) snap_bdrv_states;
>      QSIMPLEQ_INIT(&snap_bdrv_states);
>  
> +    block_job_txn = block_job_txn_new();
> +
>      /* drain all i/o before any operations */
>      bdrv_drain_all();
>  
> @@ -1914,6 +1918,7 @@ void qmp_transaction(TransactionActionList *dev_list, Error **errp)
>          state = g_malloc0(ops->instance_size);
>          state->ops = ops;
>          state->action = dev_info;
> +        state->block_job_txn = block_job_txn;
>          QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, state, entry);
>  
>          state->ops->prepare(state, &local_err);
> @@ -1940,6 +1945,7 @@ delete_and_fail:
>          }
>      }
>  exit:
> +    block_job_txn_unref(block_job_txn);
>      QSIMPLEQ_FOREACH_SAFE(state, &snap_bdrv_states, entry, next) {
>          if (state->ops->clean) {
>              state->ops->clean(state);
> 

I'd put the unref() call after the FOREACH loop, since the txn is
referenced by every state->block_job_txn, so the state->ops->clean()
operation may still try to access that field.

Max


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[Qemu-devel] [PATCH v5 11/14] block/backup: support block job transactions

[Fam Zheng]

From: Stefan Hajnoczi <stefanha@redhat.com>

Join the transaction when the 'transactional-cancel' QMP argument is
true.

This ensures that the sync bitmap is not thrown away if another block
job in the transaction is cancelled or fails.  This is critical so
incremental backup with multiple disks can be retried in case of
cancellation/failure.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/backup.c            |  25 +++++++--
 blockdev.c                | 139 ++++++++++++++++++++++++++++++++++++----------
 hmp.c                     |   2 +-
 include/block/block_int.h |   3 +-
 qapi/block-core.json      |  16 +++++-
 5 files changed, 148 insertions(+), 37 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index 9776d9c..3a3dccc 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -226,11 +226,29 @@ static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
     }
 }
 
+static void backup_commit(BlockJob *job)
+{
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
+    if (s->sync_bitmap) {
+        backup_cleanup_sync_bitmap(s, 0);
+    }
+}
+
+static void backup_abort(BlockJob *job)
+{
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
+    if (s->sync_bitmap) {
+        backup_cleanup_sync_bitmap(s, -1);
+    }
+}
+
 static const BlockJobDriver backup_job_driver = {
     .instance_size  = sizeof(BackupBlockJob),
     .job_type       = BLOCK_JOB_TYPE_BACKUP,
     .set_speed      = backup_set_speed,
     .iostatus_reset = backup_iostatus_reset,
+    .commit         = backup_commit,
+    .abort          = backup_abort,
 };
 
 static BlockErrorAction backup_error_action(BackupBlockJob *job,
@@ -443,10 +461,6 @@ static void coroutine_fn backup_run(void *opaque)
     /* wait until pending backup_do_cow() calls have completed */
     qemu_co_rwlock_wrlock(&job->flush_rwlock);
     qemu_co_rwlock_unlock(&job->flush_rwlock);
-
-    if (job->sync_bitmap) {
-        backup_cleanup_sync_bitmap(job, ret);
-    }
     hbitmap_free(job->bitmap);
 
     bdrv_iostatus_disable(target);
@@ -463,7 +477,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
                   BlockdevOnError on_source_error,
                   BlockdevOnError on_target_error,
                   BlockCompletionFunc *cb, void *opaque,
-                  Error **errp)
+                  BlockJobTxn *txn, Error **errp)
 {
     int64_t len;
 
@@ -545,6 +559,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
                        sync_bitmap : NULL;
     job->common.len = len;
     job->common.co = qemu_coroutine_create(backup_run);
+    block_job_txn_add_job(txn, &job->common);
     qemu_coroutine_enter(job->common.co, job);
     return;
 
diff --git a/blockdev.c b/blockdev.c
index 3d5e5cd..db1fdce 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1592,12 +1592,25 @@ typedef struct DriveBackupState {
     BlockJob *job;
 } DriveBackupState;
 
+static void do_drive_backup(const char *device, const char *target,
+                            bool has_format, const char *format,
+                            enum MirrorSyncMode sync,
+                            bool has_mode, enum NewImageMode mode,
+                            bool has_speed, int64_t speed,
+                            bool has_bitmap, const char *bitmap,
+                            bool has_on_source_error,
+                            BlockdevOnError on_source_error,
+                            bool has_on_target_error,
+                            BlockdevOnError on_target_error,
+                            BlockJobTxn *txn, Error **errp);
+
 static void drive_backup_prepare(BlkActionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
     BlockDriverState *bs;
     BlockBackend *blk;
     DriveBackup *backup;
+    BlockJobTxn *txn = NULL;
     Error *local_err = NULL;
 
     assert(common->action->kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
@@ -1615,15 +1628,20 @@ static void drive_backup_prepare(BlkActionState *common, Error **errp)
     state->aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(state->aio_context);
 
-    qmp_drive_backup(backup->device, backup->target,
-                     backup->has_format, backup->format,
-                     backup->sync,
-                     backup->has_mode, backup->mode,
-                     backup->has_speed, backup->speed,
-                     backup->has_bitmap, backup->bitmap,
-                     backup->has_on_source_error, backup->on_source_error,
-                     backup->has_on_target_error, backup->on_target_error,
-                     &local_err);
+    if (backup->has_transactional_cancel &&
+        backup->transactional_cancel) {
+        txn = common->block_job_txn;
+    }
+
+    do_drive_backup(backup->device, backup->target,
+                    backup->has_format, backup->format,
+                    backup->sync,
+                    backup->has_mode, backup->mode,
+                    backup->has_speed, backup->speed,
+                    backup->has_bitmap, backup->bitmap,
+                    backup->has_on_source_error, backup->on_source_error,
+                    backup->has_on_target_error, backup->on_target_error,
+                    txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
@@ -1660,12 +1678,22 @@ typedef struct BlockdevBackupState {
     AioContext *aio_context;
 } BlockdevBackupState;
 
+static void do_blockdev_backup(const char *device, const char *target,
+                               enum MirrorSyncMode sync,
+                               bool has_speed, int64_t speed,
+                               bool has_on_source_error,
+                               BlockdevOnError on_source_error,
+                               bool has_on_target_error,
+                               BlockdevOnError on_target_error,
+                               BlockJobTxn *txn, Error **errp);
+
 static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockdevBackup *backup;
     BlockDriverState *bs, *target;
     BlockBackend *blk;
+    BlockJobTxn *txn = NULL;
     Error *local_err = NULL;
 
     assert(common->action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
@@ -1694,12 +1722,17 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
     }
     aio_context_acquire(state->aio_context);
 
-    qmp_blockdev_backup(backup->device, backup->target,
-                        backup->sync,
-                        backup->has_speed, backup->speed,
-                        backup->has_on_source_error, backup->on_source_error,
-                        backup->has_on_target_error, backup->on_target_error,
-                        &local_err);
+    if (backup->has_transactional_cancel &&
+        backup->transactional_cancel) {
+        txn = common->block_job_txn;
+    }
+
+    do_blockdev_backup(backup->device, backup->target,
+                       backup->sync,
+                       backup->has_speed, backup->speed,
+                       backup->has_on_source_error, backup->on_source_error,
+                       backup->has_on_target_error, backup->on_target_error,
+                       txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
@@ -2582,15 +2615,17 @@ out:
     aio_context_release(aio_context);
 }
 
-void qmp_drive_backup(const char *device, const char *target,
-                      bool has_format, const char *format,
-                      enum MirrorSyncMode sync,
-                      bool has_mode, enum NewImageMode mode,
-                      bool has_speed, int64_t speed,
-                      bool has_bitmap, const char *bitmap,
-                      bool has_on_source_error, BlockdevOnError on_source_error,
-                      bool has_on_target_error, BlockdevOnError on_target_error,
-                      Error **errp)
+static void do_drive_backup(const char *device, const char *target,
+                            bool has_format, const char *format,
+                            enum MirrorSyncMode sync,
+                            bool has_mode, enum NewImageMode mode,
+                            bool has_speed, int64_t speed,
+                            bool has_bitmap, const char *bitmap,
+                            bool has_on_source_error,
+                            BlockdevOnError on_source_error,
+                            bool has_on_target_error,
+                            BlockdevOnError on_target_error,
+                            BlockJobTxn *txn, Error **errp)
 {
     BlockBackend *blk;
     BlockDriverState *bs;
@@ -2707,7 +2742,7 @@ void qmp_drive_backup(const char *device, const char *target,
 
     backup_start(bs, target_bs, speed, sync, bmap,
                  on_source_error, on_target_error,
-                 block_job_cb, bs, &local_err);
+                 block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
         error_propagate(errp, local_err);
@@ -2718,19 +2753,44 @@ out:
     aio_context_release(aio_context);
 }
 
+void qmp_drive_backup(const char *device, const char *target,
+                      bool has_format, const char *format,
+                      enum MirrorSyncMode sync,
+                      bool has_mode, enum NewImageMode mode,
+                      bool has_speed, int64_t speed,
+                      bool has_bitmap, const char *bitmap,
+                      bool has_on_source_error, BlockdevOnError on_source_error,
+                      bool has_on_target_error, BlockdevOnError on_target_error,
+                      bool has_transactional_cancel, bool transactional_cancel,
+                      Error **errp)
+{
+    if (has_transactional_cancel && transactional_cancel) {
+        error_setg(errp, "Transactional cancel can only be used in the "
+                   "'transaction' command");
+        return;
+    }
+
+    return do_drive_backup(device, target, has_format, format, sync,
+                           has_mode, mode, has_speed, speed,
+                           has_bitmap, bitmap,
+                           has_on_source_error, on_source_error,
+                           has_on_target_error, on_target_error,
+                           NULL, errp);
+}
+
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 {
     return bdrv_named_nodes_list(errp);
 }
 
-void qmp_blockdev_backup(const char *device, const char *target,
+void do_blockdev_backup(const char *device, const char *target,
                          enum MirrorSyncMode sync,
                          bool has_speed, int64_t speed,
                          bool has_on_source_error,
                          BlockdevOnError on_source_error,
                          bool has_on_target_error,
                          BlockdevOnError on_target_error,
-                         Error **errp)
+                         BlockJobTxn *txn, Error **errp)
 {
     BlockBackend *blk;
     BlockDriverState *bs;
@@ -2768,7 +2828,7 @@ void qmp_blockdev_backup(const char *device, const char *target,
     bdrv_ref(target_bs);
     bdrv_set_aio_context(target_bs, aio_context);
     backup_start(bs, target_bs, speed, sync, NULL, on_source_error,
-                 on_target_error, block_job_cb, bs, &local_err);
+                 on_target_error, block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
         error_propagate(errp, local_err);
@@ -2777,6 +2837,29 @@ out:
     aio_context_release(aio_context);
 }
 
+void qmp_blockdev_backup(const char *device, const char *target,
+                         enum MirrorSyncMode sync,
+                         bool has_speed, int64_t speed,
+                         bool has_on_source_error,
+                         BlockdevOnError on_source_error,
+                         bool has_on_target_error,
+                         BlockdevOnError on_target_error,
+                         bool has_transactional_cancel,
+                         bool transactional_cancel,
+                         Error **errp)
+{
+    if (has_transactional_cancel && transactional_cancel) {
+        error_setg(errp, "Transactional cancel can only be used in the "
+                   "'transaction' command");
+        return;
+    }
+
+    do_blockdev_backup(device, target, sync, has_speed, speed,
+                       has_on_source_error, on_source_error,
+                       has_on_target_error, on_target_error,
+                       NULL, errp);
+}
+
 void qmp_drive_mirror(const char *device, const char *target,
                       bool has_format, const char *format,
                       bool has_node_name, const char *node_name,
diff --git a/hmp.c b/hmp.c
index 3f807b7..11edea5 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1090,7 +1090,7 @@ void hmp_drive_backup(Monitor *mon, const QDict *qdict)
     qmp_drive_backup(device, filename, !!format, format,
                      full ? MIRROR_SYNC_MODE_FULL : MIRROR_SYNC_MODE_TOP,
                      true, mode, false, 0, false, NULL,
-                     false, 0, false, 0, &err);
+                     false, 0, false, 0, false, false, &err);
     hmp_handle_error(mon, &err);
 }
 
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 281d790..6fd07a2 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -643,6 +643,7 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target,
  * @on_target_error: The action to take upon error writing to the target.
  * @cb: Completion function for the job.
  * @opaque: Opaque pointer value passed to @cb.
+ * @txn: Transaction that this job is part of (may be NULL).
  *
  * Start a backup operation on @bs.  Clusters in @bs are written to @target
  * until the job is cancelled or manually completed.
@@ -653,7 +654,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
                   BlockdevOnError on_source_error,
                   BlockdevOnError on_target_error,
                   BlockCompletionFunc *cb, void *opaque,
-                  Error **errp);
+                  BlockJobTxn *txn, Error **errp);
 
 void blk_dev_change_media_cb(BlockBackend *blk, bool load);
 bool blk_dev_has_removable_media(BlockBackend *blk);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 7b2efb8..ddd6592 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -736,6 +736,11 @@
 #                   default 'report' (no limitations, since this applies to
 #                   a different block device than @device).
 #
+# @transactional-cancel: #optional whether failure or cancellation of other
+#                        block jobs with @transactional-cancel true in the same
+#                        transaction causes the whole group to cancel.
+#                        (Since 2.5)
+#
 # Note that @on-source-error and @on-target-error only affect background I/O.
 # If an error occurs during a guest write request, the device's rerror/werror
 # actions will be used.
@@ -747,7 +752,8 @@
             'sync': 'MirrorSyncMode', '*mode': 'NewImageMode',
             '*speed': 'int', '*bitmap': 'str',
             '*on-source-error': 'BlockdevOnError',
-            '*on-target-error': 'BlockdevOnError' } }
+            '*on-target-error': 'BlockdevOnError',
+            '*transactional-cancel': 'bool' } }
 
 ##
 # @BlockdevBackup
@@ -771,6 +777,11 @@
 #                   default 'report' (no limitations, since this applies to
 #                   a different block device than @device).
 #
+# @transactional-cancel: #optional whether failure or cancellation of other
+#                        block jobs with @transactional-cancel true in the same
+#                        transaction causes the whole group to cancel.
+#                        (Since 2.5)
+#
 # Note that @on-source-error and @on-target-error only affect background I/O.
 # If an error occurs during a guest write request, the device's rerror/werror
 # actions will be used.
@@ -782,7 +793,8 @@
             'sync': 'MirrorSyncMode',
             '*speed': 'int',
             '*on-source-error': 'BlockdevOnError',
-            '*on-target-error': 'BlockdevOnError' } }
+            '*on-target-error': 'BlockdevOnError',
+            '*transactional-cancel': 'bool' } }
 
 ##
 # @blockdev-snapshot-sync
-- 
2.4.3

Re: [Qemu-devel] [PATCH v5 11/14] block/backup: support block job transactions

[Max Reitz]

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On 07.09.2015 09:34, Fam Zheng wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
> 
> Join the transaction when the 'transactional-cancel' QMP argument is
> true.
> 
> This ensures that the sync bitmap is not thrown away if another block
> job in the transaction is cancelled or fails.  This is critical so
> incremental backup with multiple disks can be retried in case of
> cancellation/failure.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/backup.c            |  25 +++++++--
>  blockdev.c                | 139 ++++++++++++++++++++++++++++++++++++----------
>  hmp.c                     |   2 +-
>  include/block/block_int.h |   3 +-
>  qapi/block-core.json      |  16 +++++-
>  5 files changed, 148 insertions(+), 37 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index 9776d9c..3a3dccc 100644
> --- a/block/backup.c
> +++ b/block/backup.c

[snip]

> @@ -545,6 +559,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
>                         sync_bitmap : NULL;
>      job->common.len = len;
>      job->common.co = qemu_coroutine_create(backup_run);
> +    block_job_txn_add_job(txn, &job->common);

You're calling this for every single job, so the reference count of txn
will probably be job count + 1. However, block_job_txn_unref() is only
called for one block job by block_job_completed_txn_{abort,success}(). I
think you need to call block_job_txn_unref() for every completed block
job, otherwise it will be leaked if there is more than a single job in
the txn.

Max

>      qemu_coroutine_enter(job->common.co, job);
>      return;
> 


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Re: [Qemu-devel] [PATCH v5 11/14] block/backup: support block job transactions

[Eric Blake]

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On 09/07/2015 01:34 AM, Fam Zheng wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
> 
> Join the transaction when the 'transactional-cancel' QMP argument is
> true.
> 
> This ensures that the sync bitmap is not thrown away if another block
> job in the transaction is cancelled or fails.  This is critical so
> incremental backup with multiple disks can be retried in case of
> cancellation/failure.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---

Interface review:

> +void qmp_blockdev_backup(const char *device, const char *target,
> +                         enum MirrorSyncMode sync,
> +                         bool has_speed, int64_t speed,
> +                         bool has_on_source_error,
> +                         BlockdevOnError on_source_error,
> +                         bool has_on_target_error,
> +                         BlockdevOnError on_target_error,
> +                         bool has_transactional_cancel,
> +                         bool transactional_cancel,
> +                         Error **errp)
> +{
> +    if (has_transactional_cancel && transactional_cancel) {
> +        error_setg(errp, "Transactional cancel can only be used in the "
> +                   "'transaction' command");
> +        return;
> +    }

Hmm. It might be nicer if we had two separate qapi structs:

# used in 'blockdev-backup'
{ 'struct':'BlockdevBackup', 'data': { device ... on-target-error } }

# used in 'transaction'
{ 'struct':'BlockdevBackupTxn', 'base':'BlockdevBackup',
  'data': { 'transactional-cancel':'bool' } }

so that the user can't abuse the boolean from the wrong context.

[Side notes...
Furthermore, with pending changes coming down the qapi pipeline, we will
generate the C struct so that you can safely do
'(BlockdevBackup*)blockdev_backup_txn' to go from the child back to the
base class.
https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg02583.html

> +
> +    do_blockdev_backup(device, target, sync, has_speed, speed,
> +                       has_on_source_error, on_source_error,
> +                       has_on_target_error, on_target_error,
> +                       NULL, errp);
> +}

And with other changes coming down the pipe, you could write a function as:

void do_blockdev_backup(BlockdevBackup *args, Error **errp)

by adding 'box':true' to 'blockdev-backup' and make it a bit easier to
pass around all the data without breaking it into multiple parameters.
https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg02599.html

But we're not there yet - it may have to be a simplification we apply
after the fact. :)
...]

> +++ b/qapi/block-core.json
> @@ -736,6 +736,11 @@
>  #                   default 'report' (no limitations, since this applies to
>  #                   a different block device than @device).
>  #
> +# @transactional-cancel: #optional whether failure or cancellation of other
> +#                        block jobs with @transactional-cancel true in the same
> +#                        transaction causes the whole group to cancel.
> +#                        (Since 2.5)

Mention default false.

> +#
>  # Note that @on-source-error and @on-target-error only affect background I/O.
>  # If an error occurs during a guest write request, the device's rerror/werror
>  # actions will be used.
> @@ -747,7 +752,8 @@
>              'sync': 'MirrorSyncMode', '*mode': 'NewImageMode',
>              '*speed': 'int', '*bitmap': 'str',
>              '*on-source-error': 'BlockdevOnError',
> -            '*on-target-error': 'BlockdevOnError' } }
> +            '*on-target-error': 'BlockdevOnError',
> +            '*transactional-cancel': 'bool' } }

See my above comments about the idea of using a parent and child class,
rather than exposing this outside of transaction, especially since you
didn't document that it can't be used outside of a transaction.

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


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Re: [Qemu-devel] [PATCH v5 11/14] block/backup: support block job transactions

[Fam Zheng]

On Fri, 09/11 15:26, Eric Blake wrote:
> On 09/07/2015 01:34 AM, Fam Zheng wrote:
> > From: Stefan Hajnoczi <stefanha@redhat.com>
> > 
> > Join the transaction when the 'transactional-cancel' QMP argument is
> > true.
> > 
> > This ensures that the sync bitmap is not thrown away if another block
> > job in the transaction is cancelled or fails.  This is critical so
> > incremental backup with multiple disks can be retried in case of
> > cancellation/failure.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> 
> Interface review:
> 
> > +void qmp_blockdev_backup(const char *device, const char *target,
> > +                         enum MirrorSyncMode sync,
> > +                         bool has_speed, int64_t speed,
> > +                         bool has_on_source_error,
> > +                         BlockdevOnError on_source_error,
> > +                         bool has_on_target_error,
> > +                         BlockdevOnError on_target_error,
> > +                         bool has_transactional_cancel,
> > +                         bool transactional_cancel,
> > +                         Error **errp)
> > +{
> > +    if (has_transactional_cancel && transactional_cancel) {
> > +        error_setg(errp, "Transactional cancel can only be used in the "
> > +                   "'transaction' command");
> > +        return;
> > +    }
> 
> Hmm. It might be nicer if we had two separate qapi structs:
> 
> # used in 'blockdev-backup'
> { 'struct':'BlockdevBackup', 'data': { device ... on-target-error } }
> 
> # used in 'transaction'
> { 'struct':'BlockdevBackupTxn', 'base':'BlockdevBackup',
>   'data': { 'transactional-cancel':'bool' } }
> 
> so that the user can't abuse the boolean from the wrong context.

Very good point, will do that in v6.

Fam

[Qemu-devel] [PATCH v5 12/14] iotests: 124 - transactional failure test

[Fam Zheng]

From: John Snow <jsnow@redhat.com>

Use a transaction to request an incremental backup across two drives.
Coerce one of the jobs to fail, and then re-run the transaction.

Verify that no bitmap data was lost due to the partial transaction
failure.

To support the 'transactional-cancel' QMP argument name it's necessary
for transaction_action() to convert underscores in Python argument names
to hyphens for QMP argument names.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 tests/qemu-iotests/124     | 130 ++++++++++++++++++++++++++++++++++++++++++++-
 tests/qemu-iotests/124.out |   4 +-
 2 files changed, 130 insertions(+), 4 deletions(-)

diff --git a/tests/qemu-iotests/124 b/tests/qemu-iotests/124
index 9c1977e..33d00ef 100644
--- a/tests/qemu-iotests/124
+++ b/tests/qemu-iotests/124
@@ -39,7 +39,7 @@ def try_remove(img):
 def transaction_action(action, **kwargs):
     return {
         'type': action,
-        'data': kwargs
+        'data': dict((k.replace('_', '-'), v) for k, v in kwargs.iteritems())
     }
 
 
@@ -139,9 +139,12 @@ class TestIncrementalBackup(iotests.QMPTestCase):
     def do_qmp_backup(self, error='Input/output error', **kwargs):
         res = self.vm.qmp('drive-backup', **kwargs)
         self.assert_qmp(res, 'return', {})
+        return self.wait_qmp_backup(kwargs['device'], error)
 
+
+    def wait_qmp_backup(self, device, error='Input/output error'):
         event = self.vm.event_wait(name="BLOCK_JOB_COMPLETED",
-                                   match={'data': {'device': kwargs['device']}})
+                                   match={'data': {'device': device}})
         self.assertNotEqual(event, None)
 
         try:
@@ -156,6 +159,12 @@ class TestIncrementalBackup(iotests.QMPTestCase):
             return False
 
 
+    def wait_qmp_backup_cancelled(self, device):
+        event = self.vm.event_wait(name='BLOCK_JOB_CANCELLED',
+                                   match={'data': {'device': device}})
+        self.assertNotEqual(event, None)
+
+
     def create_anchor_backup(self, drive=None):
         if drive is None:
             drive = self.drives[-1]
@@ -375,6 +384,123 @@ class TestIncrementalBackup(iotests.QMPTestCase):
         self.check_backups()
 
 
+    def test_transaction_failure(self):
+        '''Test: Verify backups made from a transaction that partially fails.
+
+        Add a second drive with its own unique pattern, and add a bitmap to each
+        drive. Use blkdebug to interfere with the backup on just one drive and
+        attempt to create a coherent incremental backup across both drives.
+
+        verify a failure in one but not both, then delete the failed stubs and
+        re-run the same transaction.
+
+        verify that both incrementals are created successfully.
+        '''
+
+        # Create a second drive, with pattern:
+        drive1 = self.add_node('drive1')
+        self.img_create(drive1['file'], drive1['fmt'])
+        io_write_patterns(drive1['file'], (('0x14', 0, 512),
+                                           ('0x5d', '1M', '32k'),
+                                           ('0xcd', '32M', '124k')))
+
+        # Create a blkdebug interface to this img as 'drive1'
+        result = self.vm.qmp('blockdev-add', options={
+            'id': drive1['id'],
+            'driver': drive1['fmt'],
+            'file': {
+                'driver': 'blkdebug',
+                'image': {
+                    'driver': 'file',
+                    'filename': drive1['file']
+                },
+                'set-state': [{
+                    'event': 'flush_to_disk',
+                    'state': 1,
+                    'new_state': 2
+                }],
+                'inject-error': [{
+                    'event': 'read_aio',
+                    'errno': 5,
+                    'state': 2,
+                    'immediately': False,
+                    'once': True
+                }],
+            }
+        })
+        self.assert_qmp(result, 'return', {})
+
+        # Create bitmaps and full backups for both drives
+        drive0 = self.drives[0]
+        dr0bm0 = self.add_bitmap('bitmap0', drive0)
+        dr1bm0 = self.add_bitmap('bitmap0', drive1)
+        self.create_anchor_backup(drive0)
+        self.create_anchor_backup(drive1)
+        self.assert_no_active_block_jobs()
+        self.assertFalse(self.vm.get_qmp_events(wait=False))
+
+        # Emulate some writes
+        self.hmp_io_writes(drive0['id'], (('0xab', 0, 512),
+                                          ('0xfe', '16M', '256k'),
+                                          ('0x64', '32736k', '64k')))
+        self.hmp_io_writes(drive1['id'], (('0xba', 0, 512),
+                                          ('0xef', '16M', '256k'),
+                                          ('0x46', '32736k', '64k')))
+
+        # Create incremental backup targets
+        target0 = self.prepare_backup(dr0bm0)
+        target1 = self.prepare_backup(dr1bm0)
+
+        # Ask for a new incremental backup per-each drive,
+        # expecting drive1's backup to fail:
+        transaction = [
+            transaction_drive_backup(drive0['id'], target0, sync='incremental',
+                                     format=drive0['fmt'], mode='existing',
+                                     bitmap=dr0bm0.name,
+                                     transactional_cancel=True),
+            transaction_drive_backup(drive1['id'], target1, sync='incremental',
+                                     format=drive1['fmt'], mode='existing',
+                                     bitmap=dr1bm0.name,
+                                     transactional_cancel=True),
+        ]
+        result = self.vm.qmp('transaction', actions=transaction)
+        self.assert_qmp(result, 'return', {})
+
+        # Observe that drive0's backup is cancelled and drive1 completes with
+        # an error.
+        self.wait_qmp_backup_cancelled(drive0['id'])
+        self.assertFalse(self.wait_qmp_backup(drive1['id']))
+        error = self.vm.event_wait('BLOCK_JOB_ERROR')
+        self.assert_qmp(error, 'data', {'device': drive1['id'],
+                                        'action': 'report',
+                                        'operation': 'read'})
+        self.assertFalse(self.vm.get_qmp_events(wait=False))
+        self.assert_no_active_block_jobs()
+
+        # Delete drive0's successful target and eliminate our record of the
+        # unsuccessful drive1 target. Then re-run the same transaction.
+        dr0bm0.del_target()
+        dr1bm0.del_target()
+        target0 = self.prepare_backup(dr0bm0)
+        target1 = self.prepare_backup(dr1bm0)
+
+        # Re-run the exact same transaction.
+        result = self.vm.qmp('transaction', actions=transaction)
+        self.assert_qmp(result, 'return', {})
+
+        # Both should complete successfully this time.
+        self.assertTrue(self.wait_qmp_backup(drive0['id']))
+        self.assertTrue(self.wait_qmp_backup(drive1['id']))
+        self.make_reference_backup(dr0bm0)
+        self.make_reference_backup(dr1bm0)
+        self.assertFalse(self.vm.get_qmp_events(wait=False))
+        self.assert_no_active_block_jobs()
+
+        # And the images should of course validate.
+        self.vm.shutdown()
+        self.check_backups()
+
+
     def test_sync_dirty_bitmap_missing(self):
         self.assert_no_active_block_jobs()
         self.files.append(self.err_img)
diff --git a/tests/qemu-iotests/124.out b/tests/qemu-iotests/124.out
index 594c16f..dae404e 100644
--- a/tests/qemu-iotests/124.out
+++ b/tests/qemu-iotests/124.out
@@ -1,5 +1,5 @@
-........
+.........
 ----------------------------------------------------------------------
-Ran 8 tests
+Ran 9 tests
 
 OK
-- 
2.4.3

[Qemu-devel] [PATCH v5 13/14] qmp-commands.hx: Update the supported 'transaction' operations

[Fam Zheng]

From: Kashyap Chamarthy <kchamart@redhat.com>

Although the canonical source of reference for QMP commands is
qapi-schema.json, for consistency's sake, update qmp-commands.hx to
state the list of supported transactionable operations, namely:

    drive-backup
    blockdev-backup
    blockdev-snapshot-internal-sync
    abort
    block-dirty-bitmap-add
    block-dirty-bitmap-clear

Signed-off-by: Kashyap Chamarthy <kchamart@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 qmp-commands.hx | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/qmp-commands.hx b/qmp-commands.hx
index 9848fd8..4df59df 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1263,11 +1263,22 @@ SQMP
 transaction
 -----------
 
-Atomically operate on one or more block devices.  The only supported operations
-for now are drive-backup, internal and external snapshotting.  A list of
-dictionaries is accepted, that contains the actions to be performed.
-If there is any failure performing any of the operations, all operations
-for the group are abandoned.
+Atomically operate on one or more block devices.  Operations that are
+currently supported:
+
+    - drive-backup
+    - blockdev-backup
+    - blockdev-snapshot-sync
+    - blockdev-snapshot-internal-sync
+    - abort
+    - block-dirty-bitmap-add
+    - block-dirty-bitmap-clear
+
+Refer to the qemu/qapi-schema.json file for minimum required QEMU
+versions for these operations.  A list of dictionaries is accepted,
+that contains the actions to be performed.  If there is any failure
+performing any of the operations, all operations for the group are
+abandoned.
 
 For external snapshots, the dictionary contains the device, the file to use for
 the new snapshot, and the format.  The default format, if not specified, is
-- 
2.4.3

[Qemu-devel] [PATCH v5 14/14] tests: add BlockJobTxn unit test

[Fam Zheng]

From: Stefan Hajnoczi <stefanha@redhat.com>

The BlockJobTxn unit test verifies that both single jobs and pairs of
jobs behave as a transaction group.  Either all jobs complete
successfully or the group is cancelled.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 tests/Makefile            |   3 +
 tests/test-blockjob-txn.c | 244 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 247 insertions(+)
 create mode 100644 tests/test-blockjob-txn.c

diff --git a/tests/Makefile b/tests/Makefile
index b128e28..43cbc9f 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -45,6 +45,8 @@ check-unit-y += tests/test-thread-pool$(EXESUF)
 gcov-files-test-thread-pool-y = thread-pool.c
 gcov-files-test-hbitmap-y = util/hbitmap.c
 check-unit-y += tests/test-hbitmap$(EXESUF)
+gcov-files-test-hbitmap-y = blockjob.c
+check-unit-y += tests/test-blockjob-txn$(EXESUF)
 check-unit-y += tests/test-x86-cpuid$(EXESUF)
 # all code tested by test-x86-cpuid is inside topology.h
 gcov-files-test-x86-cpuid-y =
@@ -293,6 +295,7 @@ tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(block-obj-y) libqemuutil
 tests/test-aio$(EXESUF): tests/test-aio.o $(block-obj-y) libqemuutil.a libqemustub.a
 tests/test-rfifolock$(EXESUF): tests/test-rfifolock.o libqemuutil.a libqemustub.a
 tests/test-throttle$(EXESUF): tests/test-throttle.o $(block-obj-y) libqemuutil.a libqemustub.a
+tests/test-blockjob-txn$(EXESUF): tests/test-blockjob-txn.o $(block-obj-y) libqemuutil.a libqemustub.a
 tests/test-thread-pool$(EXESUF): tests/test-thread-pool.o $(block-obj-y) libqemuutil.a libqemustub.a
 tests/test-iov$(EXESUF): tests/test-iov.o libqemuutil.a
 tests/test-hbitmap$(EXESUF): tests/test-hbitmap.o libqemuutil.a libqemustub.a
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
new file mode 100644
index 0000000..000f70e
--- /dev/null
+++ b/tests/test-blockjob-txn.c
@@ -0,0 +1,244 @@
+/*
+ * Blockjob transactions tests
+ *
+ * Copyright Red Hat, Inc. 2015
+ *
+ * Authors:
+ *  Stefan Hajnoczi    <stefanha@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include <glib.h>
+#include "qapi/error.h"
+#include "qemu/main-loop.h"
+#include "block/blockjob.h"
+
+typedef struct {
+    BlockJob common;
+    unsigned int iterations;
+    bool use_timer;
+    int rc;
+    int *result;
+} TestBlockJob;
+
+static const BlockJobDriver test_block_job_driver = {
+    .instance_size = sizeof(TestBlockJob),
+};
+
+static void test_block_job_complete(BlockJob *job, void *opaque)
+{
+    BlockDriverState *bs = job->bs;
+    int rc = (intptr_t)opaque;
+
+    if (block_job_is_cancelled(job)) {
+        rc = -ECANCELED;
+    }
+
+    block_job_completed(job, rc);
+    bdrv_unref(bs);
+}
+
+static void coroutine_fn test_block_job_run(void *opaque)
+{
+    TestBlockJob *s = opaque;
+    BlockJob *job = &s->common;
+
+    while (s->iterations--) {
+        if (s->use_timer) {
+            block_job_sleep_ns(job, QEMU_CLOCK_REALTIME, 0);
+        } else {
+            block_job_yield(job);
+        }
+
+        if (block_job_is_cancelled(job)) {
+            break;
+        }
+    }
+
+    block_job_defer_to_main_loop(job, test_block_job_complete,
+                                 (void *)(intptr_t)s->rc);
+}
+
+typedef struct {
+    TestBlockJob *job;
+    int *result;
+} TestBlockJobCBData;
+
+static void test_block_job_cb(void *opaque, int ret)
+{
+    TestBlockJobCBData *data = opaque;
+    if (!ret && block_job_is_cancelled(&data->job->common)) {
+        ret = -ECANCELED;
+    }
+    *data->result = ret;
+    g_free(data);
+}
+
+/* Create a block job that completes with a given return code after a given
+ * number of event loop iterations.  The return code is stored in the given
+ * result pointer.
+ *
+ * The event loop iterations can either be handled automatically with a 0 delay
+ * timer, or they can be stepped manually by entering the coroutine.
+ */
+static BlockJob *test_block_job_start(unsigned int iterations,
+                                      bool use_timer,
+                                      int rc, int *result)
+{
+    BlockDriverState *bs;
+    TestBlockJob *s;
+    TestBlockJobCBData *data;
+
+    data = g_new0(TestBlockJobCBData, 1);
+    bs = bdrv_new();
+    s = block_job_create(&test_block_job_driver, bs, 0, test_block_job_cb,
+                         data, &error_abort);
+    s->iterations = iterations;
+    s->use_timer = use_timer;
+    s->rc = rc;
+    s->result = result;
+    s->common.co = qemu_coroutine_create(test_block_job_run);
+    data->job = s;
+    data->result = result;
+    qemu_coroutine_enter(s->common.co, s);
+    return &s->common;
+}
+
+static void test_single_job(int expected)
+{
+    BlockJob *job;
+    BlockJobTxn *txn;
+    int result = -EINPROGRESS;
+
+    txn = block_job_txn_new();
+    job = test_block_job_start(1, true, expected, &result);
+    block_job_txn_add_job(txn, job);
+
+    if (expected == -ECANCELED) {
+        block_job_cancel(job);
+    }
+
+    while (result == -EINPROGRESS) {
+        aio_poll(qemu_get_aio_context(), true);
+    }
+    g_assert_cmpint(result, ==, expected);
+}
+
+static void test_single_job_success(void)
+{
+    test_single_job(0);
+}
+
+static void test_single_job_failure(void)
+{
+    test_single_job(-EIO);
+}
+
+static void test_single_job_cancel(void)
+{
+    test_single_job(-ECANCELED);
+}
+
+static void test_pair_jobs(int expected1, int expected2)
+{
+    BlockJob *job1;
+    BlockJob *job2;
+    BlockJobTxn *txn;
+    int result1 = -EINPROGRESS;
+    int result2 = -EINPROGRESS;
+
+    txn = block_job_txn_new();
+    job1 = test_block_job_start(1, true, expected1, &result1);
+    block_job_txn_add_job(txn, job1);
+    job2 = test_block_job_start(2, true, expected2, &result2);
+    block_job_txn_add_job(txn, job2);
+
+    if (expected1 == -ECANCELED) {
+        block_job_cancel(job1);
+    }
+    if (expected2 == -ECANCELED) {
+        block_job_cancel(job2);
+    }
+
+    while (result1 == -EINPROGRESS || result2 == -EINPROGRESS) {
+        aio_poll(qemu_get_aio_context(), true);
+    }
+
+    /* Failure or cancellation of one job cancels the other job */
+    if (expected1 != 0) {
+        expected2 = -ECANCELED;
+    } else if (expected2 != 0) {
+        expected1 = -ECANCELED;
+    }
+
+    g_assert_cmpint(result1, ==, expected1);
+    g_assert_cmpint(result2, ==, expected2);
+}
+
+static void test_pair_jobs_success(void)
+{
+    test_pair_jobs(0, 0);
+}
+
+static void test_pair_jobs_failure(void)
+{
+    /* Test both orderings.  The two jobs run for a different number of
+     * iterations so the code path is different depending on which job fails
+     * first.
+     */
+    test_pair_jobs(-EIO, 0);
+    test_pair_jobs(0, -EIO);
+}
+
+static void test_pair_jobs_cancel(void)
+{
+    test_pair_jobs(-ECANCELED, 0);
+    test_pair_jobs(0, -ECANCELED);
+}
+
+static void test_pair_jobs_fail_cancel_race(void)
+{
+    BlockJob *job1;
+    BlockJob *job2;
+    BlockJobTxn *txn;
+    int result1 = -EINPROGRESS;
+    int result2 = -EINPROGRESS;
+
+    txn = block_job_txn_new();
+    job1 = test_block_job_start(1, true, -ECANCELED, &result1);
+    block_job_txn_add_job(txn, job1);
+    job2 = test_block_job_start(2, false, 0, &result2);
+    block_job_txn_add_job(txn, job2);
+
+    block_job_cancel(job1);
+
+    /* Now make job2 finish before the main loop kicks jobs.  This simulates
+     * the race between a pending kick and another job completing.
+     */
+    block_job_enter(job2);
+    block_job_enter(job2);
+
+    while (result1 == -EINPROGRESS || result2 == -EINPROGRESS) {
+        aio_poll(qemu_get_aio_context(), true);
+    }
+
+    g_assert_cmpint(result1, ==, -ECANCELED);
+    g_assert_cmpint(result2, ==, -ECANCELED);
+}
+
+int main(int argc, char **argv)
+{
+    qemu_init_main_loop(&error_abort);
+
+    g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/single/success", test_single_job_success);
+    g_test_add_func("/single/failure", test_single_job_failure);
+    g_test_add_func("/single/cancel", test_single_job_cancel);
+    g_test_add_func("/pair/success", test_pair_jobs_success);
+    g_test_add_func("/pair/failure", test_pair_jobs_failure);
+    g_test_add_func("/pair/cancel", test_pair_jobs_cancel);
+    g_test_add_func("/pair/fail-cancel-race", test_pair_jobs_fail_cancel_race);
+    return g_test_run();
+}
-- 
2.4.3