block: Add "drained begin/end" for internal snapshot

This ensures the atomicity of the transaction by avoiding processing of
external requests such as those from ioeventfd.

state->bs is assigned right after bdrv_drained_begin. Because it was
used as the flag for deletion or not in abort, now we need a separate
flag - InternalSnapshotState.created.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2015-10-23 11:08:13 +08:00 committed by Kevin Wolf
parent ff52bf36a3
commit 507306cc8e

View File

@ -1370,6 +1370,7 @@ typedef struct InternalSnapshotState {
BlockDriverState *bs;
AioContext *aio_context;
QEMUSnapshotInfo sn;
bool created;
} InternalSnapshotState;
static void internal_snapshot_prepare(BlkTransactionState *common,
@ -1414,6 +1415,9 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
}
bs = blk_bs(blk);
state->bs = bs;
bdrv_drained_begin(bs);
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)) {
return;
}
@ -1465,7 +1469,7 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
}
/* 4. succeed, mark a snapshot is created */
state->bs = bs;
state->created = true;
}
static void internal_snapshot_abort(BlkTransactionState *common)
@ -1476,7 +1480,7 @@ static void internal_snapshot_abort(BlkTransactionState *common)
QEMUSnapshotInfo *sn = &state->sn;
Error *local_error = NULL;
if (!bs) {
if (!state->created) {
return;
}
@ -1497,6 +1501,9 @@ static void internal_snapshot_clean(BlkTransactionState *common)
common, common);
if (state->aio_context) {
if (state->bs) {
bdrv_drained_end(state->bs);
}
aio_context_release(state->aio_context);
}
}