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blockdev: unify qmp_blockdev_backup and blockdev-backup transaction paths

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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>
This commit is contained in:
Chen Qun 2020-01-08 15:31:33 +01:00
parent 38929e0e68
commit 26ad20e4a1
1 changed files with 131 additions and 0 deletions
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131
blockdev-unify-qmp_blockdev_backup-and-blockdev-back.patch Normal file
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@ -0,0 +1,131 @@
From 6d89e4923e9c341975dbfdd2bae153ba367a1b79 Mon Sep 17 00:00:00 2001
From: Sergio Lopez <slp@redhat.com>
Date: Wed, 8 Jan 2020 15:31:33 +0100
Subject: [PATCH] blockdev: unify qmp_blockdev_backup and blockdev-backup
transaction paths
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>
---
blockdev.c | 60 ++++++++++++------------------------------------------
1 file changed, 13 insertions(+), 47 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 7016054688..d3309c205a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1983,16 +1983,13 @@ 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;
@@ -2002,8 +1999,8 @@ 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;
}
@@ -2014,13 +2011,10 @@ 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);
}
@@ -3672,41 +3666,13 @@ 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.
--
2.27.0