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-rw-r--r--block/io.c72
-rw-r--r--include/block/block_int-common.h18
-rw-r--r--include/block/block_int-io.h9
3 files changed, 99 insertions, 0 deletions
diff --git a/block/io.c b/block/io.c
index 8bee484..f0c8da6 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3654,3 +3654,75 @@ void bdrv_cancel_in_flight(BlockDriverState *bs)
bs->drv->bdrv_cancel_in_flight(bs);
}
}
+
+int coroutine_fn
+bdrv_co_preadv_snapshot(BdrvChild *child, int64_t offset, int64_t bytes,
+ QEMUIOVector *qiov, size_t qiov_offset)
+{
+ BlockDriverState *bs = child->bs;
+ BlockDriver *drv = bs->drv;
+ int ret;
+ IO_CODE();
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+
+ if (!drv->bdrv_co_preadv_snapshot) {
+ return -ENOTSUP;
+ }
+
+ bdrv_inc_in_flight(bs);
+ ret = drv->bdrv_co_preadv_snapshot(bs, offset, bytes, qiov, qiov_offset);
+ bdrv_dec_in_flight(bs);
+
+ return ret;
+}
+
+int coroutine_fn
+bdrv_co_snapshot_block_status(BlockDriverState *bs,
+ bool want_zero, int64_t offset, int64_t bytes,
+ int64_t *pnum, int64_t *map,
+ BlockDriverState **file)
+{
+ BlockDriver *drv = bs->drv;
+ int ret;
+ IO_CODE();
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+
+ if (!drv->bdrv_co_snapshot_block_status) {
+ return -ENOTSUP;
+ }
+
+ bdrv_inc_in_flight(bs);
+ ret = drv->bdrv_co_snapshot_block_status(bs, want_zero, offset, bytes,
+ pnum, map, file);
+ bdrv_dec_in_flight(bs);
+
+ return ret;
+}
+
+int coroutine_fn
+bdrv_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes)
+{
+ BlockDriver *drv = bs->drv;
+ int ret;
+ IO_CODE();
+
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+
+ if (!drv->bdrv_co_pdiscard_snapshot) {
+ return -ENOTSUP;
+ }
+
+ bdrv_inc_in_flight(bs);
+ ret = drv->bdrv_co_pdiscard_snapshot(bs, offset, bytes);
+ bdrv_dec_in_flight(bs);
+
+ return ret;
+}
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 5a04c77..4ba04d0 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -598,6 +598,24 @@ struct BlockDriver {
int64_t *map, BlockDriverState **file);
/*
+ * Snapshot-access API.
+ *
+ * Block-driver may provide snapshot-access API: special functions to access
+ * some internal "snapshot". The functions are similar with normal
+ * read/block_status/discard handler, but don't have any specific handling
+ * in generic block-layer: no serializing, no alignment, no tracked
+ * requests. So, block-driver that realizes these APIs is fully responsible
+ * for synchronization between snapshot-access API and normal IO requests.
+ */
+ int coroutine_fn (*bdrv_co_preadv_snapshot)(BlockDriverState *bs,
+ int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
+ int coroutine_fn (*bdrv_co_snapshot_block_status)(BlockDriverState *bs,
+ bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
+ int64_t *map, BlockDriverState **file);
+ int coroutine_fn (*bdrv_co_pdiscard_snapshot)(BlockDriverState *bs,
+ int64_t offset, int64_t bytes);
+
+ /*
* Invalidate any cached meta-data.
*/
void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs,
diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h
index 3da5f01..bb45420 100644
--- a/include/block/block_int-io.h
+++ b/include/block/block_int-io.h
@@ -33,6 +33,15 @@
* the I/O API.
*/
+int coroutine_fn bdrv_co_preadv_snapshot(BdrvChild *child,
+ int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
+int coroutine_fn bdrv_co_snapshot_block_status(BlockDriverState *bs,
+ bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
+ int64_t *map, BlockDriverState **file);
+int coroutine_fn bdrv_co_pdiscard_snapshot(BlockDriverState *bs,
+ int64_t offset, int64_t bytes);
+
+
int coroutine_fn bdrv_co_preadv(BdrvChild *child,
int64_t offset, int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);