[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH 06/12] block: Introduce "drained begin/end" API
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH 06/12] block: Introduce "drained begin/end" API |
Date: |
Fri, 9 Oct 2015 13:45:20 +0800 |
The semantics is that after bdrv_drained_begin(bs), bs will not get new external
requests until the matching bdrv_drained_end(bs).
Signed-off-by: Fam Zheng <address@hidden>
---
block.c | 2 ++
block/io.c | 18 ++++++++++++++++++
include/block/block.h | 19 +++++++++++++++++++
include/block/block_int.h | 2 ++
4 files changed, 41 insertions(+)
diff --git a/block.c b/block.c
index 1f90b47..9b28a07 100644
--- a/block.c
+++ b/block.c
@@ -2058,6 +2058,8 @@ static void bdrv_move_feature_fields(BlockDriverState
*bs_dest,
bs_dest->device_list = bs_src->device_list;
bs_dest->blk = bs_src->blk;
+ bs_dest->quiesce_counter = bs_src->quiesce_counter;
+
memcpy(bs_dest->op_blockers, bs_src->op_blockers,
sizeof(bs_dest->op_blockers));
}
diff --git a/block/io.c b/block/io.c
index 94e18e6..b0dde7f 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2618,3 +2618,21 @@ void bdrv_flush_io_queue(BlockDriverState *bs)
}
bdrv_start_throttled_reqs(bs);
}
+
+void bdrv_drained_begin(BlockDriverState *bs)
+{
+ if (bs->quiesce_counter++) {
+ return;
+ }
+ aio_disable_clients(bdrv_get_aio_context(bs), AIO_CLIENT_EXTERNAL);
+ bdrv_drain(bs);
+}
+
+void bdrv_drained_end(BlockDriverState *bs)
+{
+ assert(bs->quiesce_counter > 0);
+ if (--bs->quiesce_counter > 0) {
+ return;
+ }
+ aio_enable_clients(bdrv_get_aio_context(bs), AIO_CLIENT_EXTERNAL);
+}
diff --git a/include/block/block.h b/include/block/block.h
index 2dd6630..c4f6eef 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -619,4 +619,23 @@ void bdrv_flush_io_queue(BlockDriverState *bs);
BlockAcctStats *bdrv_get_stats(BlockDriverState *bs);
+/**
+ * bdrv_drained_begin:
+ *
+ * Begin a quiesced section for exclusive access to the BDS, by disabling
+ * external request sources including NBD server and device model. Note that
+ * this doesn't block timers or coroutines from submitting more requests, which
+ * means block_job_pause is still necessary.
+ *
+ * This function can be recursive.
+ */
+void bdrv_drained_begin(BlockDriverState *bs);
+
+/**
+ * bdrv_drained_end:
+ *
+ * End a quiescent section started by bdrv_drained_begin().
+ */
+void bdrv_drained_end(BlockDriverState *bs);
+
#endif
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 14ad4c3..7c58221 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -456,6 +456,8 @@ struct BlockDriverState {
/* threshold limit for writes, in bytes. "High water mark". */
uint64_t write_threshold_offset;
NotifierWithReturn write_threshold_notifier;
+
+ int quiesce_counter;
};
--
2.5.3
- [Qemu-devel] [PATCH 00/12] block: bdrv_drained_begin/end for transactions on dataplane devices, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 02/12] aio: Save fd client type to AioHandler, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 03/12] nbd: Mark fd handlers client type as "external", Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 07/12] block: Add "drained begin/end" for transactional external snapshot, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 10/12] block: Add "drained begin/end" for internal snapshot, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 11/12] block: Introduce BlockDriver.bdrv_drain callback, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 08/12] block: Add "drained begin/end" for transactional backup, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 06/12] block: Introduce "drained begin/end" API,
Fam Zheng <=
- [Qemu-devel] [PATCH 01/12] aio: Introduce "type" in aio_set_fd_handler and aio_set_event_notifier, Fam Zheng, 2015/10/09
- [Qemu-devel] [PATCH 05/12] aio: introduce aio_{disable, enable}_clients, Fam Zheng, 2015/10/09
[Qemu-devel] [PATCH 09/12] block: Add "drained begin/end" for transactional blockdev-backup, Fam Zheng, 2015/10/09
[Qemu-devel] [PATCH 04/12] dataplane: Mark host notifiers' client type as "external", Fam Zheng, 2015/10/10