From 959955217f745f1ee6cbea97314efe69f2d7dc08 Mon Sep 17 00:00:00 2001

From: Sergio Lopez Pascual <slp@redhat.com>

Date: Fri, 7 Feb 2020 11:27:43 +0000

Subject: [PATCH 10/18] blockdev: unify qmp_blockdev_backup and blockdev-backup

 transaction paths

RH-Author: Sergio Lopez Pascual <slp@redhat.com>

Message-id: <20200207112749.25073-4-slp@redhat.com>

Patchwork-id: 93756

O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH v2 3/9] blockdev: unify qmp_blockdev_backup and blockdev-backup transaction paths

Bugzilla: 1745606 1746217 1773517 1779036 1782111 1782175 1783965

RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

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

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

Issuing a blockdev-backup from qmp_blockdev_backup takes a slightly

different path than when it's issued from a transaction. In the code,

this is manifested as some redundancy between do_blockdev_backup() and

blockdev_backup_prepare().

This change unifies both paths, merging do_blockdev_backup() and

blockdev_backup_prepare(), and changing qmp_blockdev_backup() to

create a transaction instead of calling do_backup_common() direcly.

As a side-effect, now qmp_blockdev_backup() is executed inside a

drained section, as it happens when creating a blockdev-backup

transaction. This change is visible from the user's perspective, as

the job gets paused and immediately resumed before starting the actual

work.

Signed-off-by: Sergio Lopez <slp@redhat.com>

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

Reviewed-by: Kevin Wolf <kwolf@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 5b7bfe515ecbd584b40ff6e41d2fd8b37c7d5139)

Signed-off-by: Sergio Lopez <slp@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 blockdev.c | 60 +++++++++++++-----------------------------------------------

 1 file changed, 13 insertions(+), 47 deletions(-)

diff --git a/blockdev.c b/blockdev.c

index 5e85fc0..152a0f7 100644

--- a/blockdev.c

+++ b/blockdev.c

@@ -1940,16 +1940,13 @@ typedef struct BlockdevBackupState {

     BlockJob *job;

 } BlockdevBackupState;

-static BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,

-                                    Error **errp);

-

 static void blockdev_backup_prepare(BlkActionState *common, Error **errp)

 {

     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);

     BlockdevBackup *backup;

-    BlockDriverState *bs, *target;

+    BlockDriverState *bs;

+    BlockDriverState *target_bs;

     AioContext *aio_context;

-    Error *local_err = NULL;

     assert(common->action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);

     backup = common->action->u.blockdev_backup.data;

@@ -1959,8 +1956,8 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)

         return;

     }

-    target = bdrv_lookup_bs(backup->target, backup->target, errp);

-    if (!target) {

+    target_bs = bdrv_lookup_bs(backup->target, backup->target, errp);

+    if (!target_bs) {

         return;

     }

@@ -1971,13 +1968,10 @@ static void blockdev_backup_prepare(BlkActionState *common, Error **errp)

     /* Paired with .clean() */

     bdrv_drained_begin(state->bs);

-    state->job = do_blockdev_backup(backup, common->block_job_txn, &local_err);

-    if (local_err) {

-        error_propagate(errp, local_err);

-        goto out;

-    }

+    state->job = do_backup_common(qapi_BlockdevBackup_base(backup),

+                                  bs, target_bs, aio_context,

+                                  common->block_job_txn, errp);

-out:

     aio_context_release(aio_context);

 }

@@ -3695,41 +3689,13 @@ XDbgBlockGraph *qmp_x_debug_query_block_graph(Error **errp)

     return bdrv_get_xdbg_block_graph(errp);

 }

-BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,

-                             Error **errp)

+void qmp_blockdev_backup(BlockdevBackup *backup, Error **errp)

 {

-    BlockDriverState *bs;

-    BlockDriverState *target_bs;

-    AioContext *aio_context;

-    BlockJob *job;

-

-    bs = bdrv_lookup_bs(backup->device, backup->device, errp);

-    if (!bs) {

-        return NULL;

-    }

-

-    target_bs = bdrv_lookup_bs(backup->target, backup->target, errp);

-    if (!target_bs) {

-        return NULL;

-    }

-

-    aio_context = bdrv_get_aio_context(bs);

-    aio_context_acquire(aio_context);

-

-    job = do_backup_common(qapi_BlockdevBackup_base(backup),

-                           bs, target_bs, aio_context, txn, errp);

-

-    aio_context_release(aio_context);

-    return job;

-}

-

-void qmp_blockdev_backup(BlockdevBackup *arg, Error **errp)

-{

-    BlockJob *job;

-    job = do_blockdev_backup(arg, NULL, errp);

-    if (job) {

-        job_start(&job->job);

-    }

+    TransactionAction action = {

+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP,

+        .u.blockdev_backup.data = backup,

+    };

+    blockdev_do_action(&action, errp);

 }

 /* Parameter check and block job starting for drive mirroring.

-- 

1.8.3.1