Commit da763e83 authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

block: Add "drained begin/end" for transactional external snapshot 



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

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 51288d79

blockdev.c

+9 −2
Original line number Diff line number Diff line
@@ -1569,6 +1569,7 @@ static void external_snapshot_prepare(BlkTransactionState *common, 
    /* Acquire AioContext now so any threads operating on old_bs stop */

    state->aio_context = bdrv_get_aio_context(state->old_bs);

    aio_context_acquire(state->aio_context);

    bdrv_drained_begin(state->old_bs);



    if (!bdrv_is_inserted(state->old_bs)) {

        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
@@ -1638,8 +1639,6 @@ static void external_snapshot_commit(BlkTransactionState *common) 
     * don't want to abort all of them if one of them fails the reopen */

    bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR,

                NULL);



    aio_context_release(state->aio_context);

}



static void external_snapshot_abort(BlkTransactionState *common)
@@ -1649,7 +1648,14 @@ static void external_snapshot_abort(BlkTransactionState *common) 
    if (state->new_bs) {

        bdrv_unref(state->new_bs);

    }

}



static void external_snapshot_clean(BlkTransactionState *common)

{

    ExternalSnapshotState *state =

                             DO_UPCAST(ExternalSnapshotState, common, common);

    if (state->aio_context) {

        bdrv_drained_end(state->old_bs);

        aio_context_release(state->aio_context);

    }

}
@@ -1809,6 +1815,7 @@ static const BdrvActionOps actions[] = { 
        .prepare  = external_snapshot_prepare,

        .commit   = external_snapshot_commit,

        .abort = external_snapshot_abort,

        .clean = external_snapshot_clean,

    },

    [TRANSACTION_ACTION_KIND_DRIVE_BACKUP] = {

        .instance_size = sizeof(DriveBackupState),