diff options
| -rw-r--r-- | block.c | 34 | ||||
| -rw-r--r-- | block/io.c | 60 | ||||
| -rw-r--r-- | include/block/block.h | 1 | ||||
| -rw-r--r-- | include/block/block_int.h | 1 |
4 files changed, 79 insertions, 17 deletions
diff --git a/block.c b/block.c index c8586f41ba..6c128007fd 100644 --- a/block.c +++ b/block.c @@ -333,6 +333,10 @@ BlockDriverState *bdrv_new(void) qemu_co_queue_init(&bs->flush_queue); + for (i = 0; i < bdrv_drain_all_count; i++) { + bdrv_drained_begin(bs); + } + QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); return bs; @@ -1164,7 +1168,7 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, int open_flags, Error **errp) { Error *local_err = NULL; - int ret; + int i, ret; bdrv_assign_node_name(bs, node_name, &local_err); if (local_err) { @@ -1212,6 +1216,12 @@ static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, assert(bdrv_min_mem_align(bs) != 0); assert(is_power_of_2(bs->bl.request_alignment)); + for (i = 0; i < bs->quiesce_counter; i++) { + if (drv->bdrv_co_drain_begin) { + drv->bdrv_co_drain_begin(bs); + } + } + return 0; open_failed: bs->drv = NULL; @@ -2033,7 +2043,12 @@ static void bdrv_replace_child_noperm(BdrvChild *child, child->role->detach(child); } if (old_bs->quiesce_counter && child->role->drained_end) { - for (i = 0; i < old_bs->quiesce_counter; i++) { + int num = old_bs->quiesce_counter; + if (child->role->parent_is_bds) { + num -= bdrv_drain_all_count; + } + assert(num >= 0); + for (i = 0; i < num; i++) { child->role->drained_end(child); } } @@ -2045,7 +2060,12 @@ static void bdrv_replace_child_noperm(BdrvChild *child, if (new_bs) { QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); if (new_bs->quiesce_counter && child->role->drained_begin) { - for (i = 0; i < new_bs->quiesce_counter; i++) { + int num = new_bs->quiesce_counter; + if (child->role->parent_is_bds) { + num -= bdrv_drain_all_count; + } + assert(num >= 0); + for (i = 0; i < num; i++) { child->role->drained_begin(child); } } @@ -4049,6 +4069,14 @@ BlockDriverState *bdrv_next_node(BlockDriverState *bs) return QTAILQ_NEXT(bs, node_list); } +BlockDriverState *bdrv_next_all_states(BlockDriverState *bs) +{ + if (!bs) { + return QTAILQ_FIRST(&all_bdrv_states); + } + return QTAILQ_NEXT(bs, bs_list); +} + const char *bdrv_get_node_name(const BlockDriverState *bs) { return bs->node_name; diff --git a/block/io.c b/block/io.c index 1834a14aa6..ef4fedd364 100644 --- a/block/io.c +++ b/block/io.c @@ -38,6 +38,8 @@ /* Maximum bounce buffer for copy-on-read and write zeroes, in bytes */ #define MAX_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS) +static AioWait drain_all_aio_wait; + static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags); @@ -472,6 +474,29 @@ static void bdrv_drain_assert_idle(BlockDriverState *bs) } } +unsigned int bdrv_drain_all_count = 0; + +static bool bdrv_drain_all_poll(void) +{ + BlockDriverState *bs = NULL; + bool result = false; + + /* Execute pending BHs first (may modify the graph) and check everything + * else only after the BHs have executed. */ + while (aio_poll(qemu_get_aio_context(), false)); + + /* bdrv_drain_poll() can't make changes to the graph and we are holding the + * main AioContext lock, so iterating bdrv_next_all_states() is safe. */ + while ((bs = bdrv_next_all_states(bs))) { + AioContext *aio_context = bdrv_get_aio_context(bs); + aio_context_acquire(aio_context); + result |= bdrv_drain_poll(bs, false, NULL, true); + aio_context_release(aio_context); + } + + return result; +} + /* * Wait for pending requests to complete across all BlockDriverStates * @@ -486,45 +511,51 @@ static void bdrv_drain_assert_idle(BlockDriverState *bs) */ void bdrv_drain_all_begin(void) { - BlockDriverState *bs; - BdrvNextIterator it; + BlockDriverState *bs = NULL; if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(NULL, true, false, NULL, false, true); + bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true); return; } - /* BDRV_POLL_WHILE() for a node can only be called from its own I/O thread - * or the main loop AioContext. We potentially use BDRV_POLL_WHILE() on - * nodes in several different AioContexts, so make sure we're in the main - * context. */ + /* AIO_WAIT_WHILE() with a NULL context can only be called from the main + * loop AioContext, so make sure we're in the main context. */ assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + assert(bdrv_drain_all_count < INT_MAX); + bdrv_drain_all_count++; - for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { + /* Quiesce all nodes, without polling in-flight requests yet. The graph + * cannot change during this loop. */ + while ((bs = bdrv_next_all_states(bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_begin(bs, true, NULL, false, true); + bdrv_do_drained_begin(bs, false, NULL, true, false); aio_context_release(aio_context); } - for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { + /* Now poll the in-flight requests */ + AIO_WAIT_WHILE(&drain_all_aio_wait, NULL, bdrv_drain_all_poll()); + + while ((bs = bdrv_next_all_states(bs))) { bdrv_drain_assert_idle(bs); } } void bdrv_drain_all_end(void) { - BlockDriverState *bs; - BdrvNextIterator it; + BlockDriverState *bs = NULL; - for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { + while ((bs = bdrv_next_all_states(bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); - bdrv_do_drained_end(bs, true, NULL, false); + bdrv_do_drained_end(bs, false, NULL, true); aio_context_release(aio_context); } + + assert(bdrv_drain_all_count > 0); + bdrv_drain_all_count--; } void bdrv_drain_all(void) @@ -647,6 +678,7 @@ void bdrv_inc_in_flight(BlockDriverState *bs) void bdrv_wakeup(BlockDriverState *bs) { aio_wait_kick(bdrv_get_aio_wait(bs)); + aio_wait_kick(&drain_all_aio_wait); } void bdrv_dec_in_flight(BlockDriverState *bs) diff --git a/include/block/block.h b/include/block/block.h index 836746e4e1..b1d6fdb97a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -421,6 +421,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device, Error **errp); bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base); BlockDriverState *bdrv_next_node(BlockDriverState *bs); +BlockDriverState *bdrv_next_all_states(BlockDriverState *bs); typedef struct BdrvNextIterator { enum { diff --git a/include/block/block_int.h b/include/block/block_int.h index 1abfc26d76..7cd7eed83b 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -854,6 +854,7 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); +extern unsigned int bdrv_drain_all_count; void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent); void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent); |