Commit 507306cc authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

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: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent ff52bf36

blockdev.c

+9 −2
Original line number Diff line number Diff line
@@ -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);

    }

}