From: Fam Zheng <f...@redhat.com> This adds three qmp commands to transactions.
Users can stop a dirty bitmap, start backup of it, and start another dirty bitmap atomically, so that the dirty bitmap is tracked incrementally and we don't miss any write. Signed-off-by: Fam Zheng <f...@redhat.com> Signed-off-by: John Snow <js...@redhat.com> --- blockdev.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ qapi-schema.json | 5 ++- 2 files changed, 109 insertions(+), 1 deletion(-) diff --git a/blockdev.c b/blockdev.c index 114a94c..e283581 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1602,6 +1602,94 @@ static void drive_backup_clean(BlkTransactionState *common) } } +static void block_dirty_bitmap_add_prepare(BlkTransactionState *common, + Error **errp) +{ + BlockDirtyBitmapAdd *action; + + action = common->action->block_dirty_bitmap_add; + qmp_block_dirty_bitmap_add(action->node_ref, action->name, + action->has_granularity, action->granularity, + errp); +} + +static void block_dirty_bitmap_add_abort(BlkTransactionState *common) +{ + BlockDirtyBitmapAdd *action; + + action = common->action->block_dirty_bitmap_add; + /* Should not fail meaningfully: IF the bitmap was added via .prepare(), + * then the node reference and bitmap name must have been valid. + * THUS: any failure here could only indicate the lack of a bitmap at all. + */ + qmp_block_dirty_bitmap_remove(action->node_ref, action->name, NULL); +} + +typedef struct BlockDirtyBitmapState { + BlkTransactionState common; + BdrvDirtyBitmap *bitmap; + AioContext *aio_context; +} BlockDirtyBitmapState; + +/** + * Enable and Disable re-use the same preparation. + */ +static void block_dirty_bitmap_toggle_prepare(BlkTransactionState *common, + Error **errp) +{ + BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState, + common, common); + BlockDirtyBitmap *action; + BlockDriverState *bs; + + /* We may be used by either enable or disable; + * We use the "enable" member of the union here, + * but "disable" should be functionally equivalent: */ + action = common->action->block_dirty_bitmap_enable; + assert(action == common->action->block_dirty_bitmap_disable); + + state->bitmap = block_dirty_bitmap_lookup(action->node_ref, + action->name, + &bs, + errp); + if (!state->bitmap) { + return; + } + + if (bdrv_dirty_bitmap_frozen(state->bitmap)) { + error_setg(errp, "Cannot enable/disable a bitmap that is frozen.\n"); + return; + } + + /* AioContext is released in .clean() */ + state->aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(state->aio_context); +} + +static void block_dirty_bitmap_enable_commit(BlkTransactionState *common) +{ + BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState, + common, common); + bdrv_enable_dirty_bitmap(state->bitmap); +} + +static void block_dirty_bitmap_disable_commit(BlkTransactionState *common) +{ + BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState, + common, common); + bdrv_disable_dirty_bitmap(state->bitmap); +} + +static void block_dirty_bitmap_toggle_clean(BlkTransactionState *common) +{ + BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState, + common, common); + + if (state->aio_context) { + aio_context_release(state->aio_context); + } +} + static void abort_prepare(BlkTransactionState *common, Error **errp) { error_setg(errp, "Transaction aborted using Abort action"); @@ -1636,6 +1724,23 @@ static const BdrvActionOps actions[] = { .abort = internal_snapshot_abort, .clean = internal_snapshot_clean, }, + [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ADD] = { + .instance_size = sizeof(BlkTransactionState), + .prepare = block_dirty_bitmap_add_prepare, + .abort = block_dirty_bitmap_add_abort, + }, + [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ENABLE] = { + .instance_size = sizeof(BlockDirtyBitmapState), + .prepare = block_dirty_bitmap_toggle_prepare, + .commit = block_dirty_bitmap_enable_commit, + .clean = block_dirty_bitmap_toggle_clean, + }, + [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_DISABLE] = { + .instance_size = sizeof(BlockDirtyBitmapState), + .prepare = block_dirty_bitmap_toggle_prepare, + .commit = block_dirty_bitmap_disable_commit, + .clean = block_dirty_bitmap_toggle_clean, + }, }; /* diff --git a/qapi-schema.json b/qapi-schema.json index 563b4ad..85f55d9 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -1260,7 +1260,10 @@ 'blockdev-snapshot-sync': 'BlockdevSnapshot', 'drive-backup': 'DriveBackup', 'abort': 'Abort', - 'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal' + 'blockdev-snapshot-internal-sync': 'BlockdevSnapshotInternal', + 'block-dirty-bitmap-add': 'BlockDirtyBitmapAdd', + 'block-dirty-bitmap-enable': 'BlockDirtyBitmap', + 'block-dirty-bitmap-disable': 'BlockDirtyBitmap' } } ## -- 1.9.3