On 2015-02-09 at 20:35, John Snow wrote:
This adds four 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.
For starting a new incremental backup chain, users can also chain
together a bitmap clear and a full block backup.
Signed-off-by: Fam Zheng <f...@redhat.com>
Signed-off-by: John Snow <js...@redhat.com>
---
blockdev.c | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
qapi-schema.json | 6 ++-
2 files changed, 160 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 83d0608..ed96e72 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1675,6 +1675,138 @@ static void blockdev_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, 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, action->name, NULL);
What if block_dirty_bitmap_add_prepare() failed because a bitmap with
that name already exists? Wouldn't this silently delete that existing
bitmap?
I think you should store whether qmp_block_dirty_bitmap_add() was
successful and only call qmp_block_dirty_bitmap_remove() if it was, and
since you say it cannot fail (which I agree on), with &error_abort as
the last argument.
+}
+
+typedef struct BlockDirtyBitmapState {
+ BlkTransactionState common;
+ BdrvDirtyBitmap *bitmap;
+ BlockDriverState *bs;
+ 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,
+ action->name,
+ &bs,
+ errp);
+ if (!state->bitmap) {
+ return;
+ }
+
+ if (bdrv_dirty_bitmap_frozen(state->bitmap)) {
+ error_setg(errp, "Cannot modify a frozen bitmap.\n");
I'm sorry.\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 block_dirty_bitmap_clear_prepare(BlkTransactionState *common,
+ Error **errp)
+{
+ BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+ common, common);
+ BlockDirtyBitmap *action;
+
+ action = common->action->block_dirty_bitmap_clear;
+ state->bitmap = block_dirty_bitmap_lookup(action->node,
+ action->name,
+ &state->bs,
+ errp);
+ if (!state->bitmap) {
+ return;
+ }
+
+ if (bdrv_dirty_bitmap_frozen(state->bitmap)) {
+ error_setg(errp, "Cannot modify a frozen bitmap.\n");
+ return;
+ }
Following your reply regarding patch 8, this needs a check whether the
bitmap is disabled, too.\n
+
+ /* AioContext is released in .clean() */
+ state->aio_context = bdrv_get_aio_context(state->bs);
+ aio_context_acquire(state->aio_context);
+}
+
+static void block_dirty_bitmap_clear_commit(BlkTransactionState *common)
+{
+ BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+ common, common);
+ bdrv_clear_dirty_bitmap(state->bitmap);
+}
+
+static void block_dirty_bitmap_clear_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");
@@ -1715,6 +1847,29 @@ 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,
+ },
+ [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_CLEAR] = {
+ .instance_size = sizeof(BlockDirtyBitmapState),
+ .prepare = block_dirty_bitmap_clear_prepare,
+ .commit = block_dirty_bitmap_clear_commit,
+ .clean = block_dirty_bitmap_clear_clean,
+ }
};
/*
diff --git a/qapi-schema.json b/qapi-schema.json
index e16f8eb..cf4aa12 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1339,7 +1339,11 @@
'drive-backup': 'DriveBackup',
'blockdev-backup': 'BlockdevBackup',
'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',
+ 'block-dirty-bitmap-clear': 'BlockDirtyBitmap'
Maybe add version information to the comment above this union?
Max
} }
##
