From: Zhu Yangyang <zhuyangyan...@huawei.com> The bdrv_drained_begin() function is a blocking function. In scenarios where network storage is used and network links fail, it may block for a long time. Therefore, we add a timeout parameter to control the duration of the block.
Since bdrv_drained_begin() has been widely adopted, both bdrv_drained_begin() and bdrv_drained_begin_timeout() will be retained. Signed-off-by: Zhu Yangyang <zhuyangyan...@huawei.com> --- block/io.c | 55 ++++++++++++++++++++++++++++++------- include/block/aio-wait.h | 58 ++++++++++++++++++++++++++++++++++++++++ include/block/block-io.h | 7 +++++ util/aio-wait.c | 7 +++++ 4 files changed, 117 insertions(+), 10 deletions(-) diff --git a/block/io.c b/block/io.c index d369b994df..03b8b2dca7 100644 --- a/block/io.c +++ b/block/io.c @@ -255,6 +255,8 @@ typedef struct { bool begin; bool poll; BdrvChild *parent; + int ret; + int64_t timeout; } BdrvCoDrainData; /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ @@ -283,6 +285,8 @@ static bool bdrv_drain_poll_top_level(BlockDriverState *bs, return bdrv_drain_poll(bs, ignore_parent, false); } +static int bdrv_do_drained_begin_timeout(BlockDriverState *bs, + BdrvChild *parent, bool poll, int64_t timeout); static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, bool poll); static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent); @@ -296,7 +300,8 @@ static void bdrv_co_drain_bh_cb(void *opaque) if (bs) { bdrv_dec_in_flight(bs); if (data->begin) { - bdrv_do_drained_begin(bs, data->parent, data->poll); + data->ret = bdrv_do_drained_begin_timeout( + bs, data->parent, data->poll, data->timeout); } else { assert(!data->poll); bdrv_do_drained_end(bs, data->parent); @@ -310,10 +315,11 @@ static void bdrv_co_drain_bh_cb(void *opaque) aio_co_wake(co); } -static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, - bool begin, - BdrvChild *parent, - bool poll) +static int coroutine_fn bdrv_co_yield_to_drain_timeout(BlockDriverState *bs, + bool begin, + BdrvChild *parent, + bool poll, + int64_t timeout) { BdrvCoDrainData data; Coroutine *self = qemu_coroutine_self(); @@ -329,6 +335,8 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, .begin = begin, .parent = parent, .poll = poll, + .timeout = timeout, + .ret = 0 }; if (bs) { @@ -342,16 +350,25 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, /* If we are resumed from some other event (such as an aio completion or a * timer callback), it is a bug in the caller that should be fixed. */ assert(data.done); + return data.ret; } -static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, - bool poll) +static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, + bool begin, + BdrvChild *parent, + bool poll) +{ + bdrv_co_yield_to_drain_timeout(bs, begin, parent, poll, -1); +} + +static int bdrv_do_drained_begin_timeout(BlockDriverState *bs, + BdrvChild *parent, bool poll, int64_t timeout_ms) { IO_OR_GS_CODE(); if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs, true, parent, poll); - return; + return bdrv_co_yield_to_drain_timeout(bs, true, parent, poll, + timeout_ms); } GLOBAL_STATE_CODE(); @@ -375,8 +392,20 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, * nodes. */ if (poll) { - BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); + if (timeout_ms < 0) { + BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent)); + } else { + return BDRV_POLL_WHILE_TIMEOUT( + bs, bdrv_drain_poll_top_level(bs, parent), timeout_ms); + } } + return 0; +} + +static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent, + bool poll) +{ + bdrv_do_drained_begin_timeout(bs, parent, poll, -1); } void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent) @@ -390,6 +419,12 @@ bdrv_drained_begin(BlockDriverState *bs) IO_OR_GS_CODE(); bdrv_do_drained_begin(bs, NULL, true); } +int coroutine_mixed_fn +bdrv_drained_begin_timeout(BlockDriverState *bs, int64_t timeout_ms) +{ + IO_OR_GS_CODE(); + return bdrv_do_drained_begin_timeout(bs, NULL, true, timeout_ms); +} /** * This function does not poll, nor must any of its recursively called diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h index cf5e8bde1c..efbcb9777a 100644 --- a/include/block/aio-wait.h +++ b/include/block/aio-wait.h @@ -28,6 +28,8 @@ #include "block/aio.h" #include "qemu/main-loop.h" +#define AIO_WAIT_INTERVAL 10 /* ms */ + /** * AioWait: * @@ -56,6 +58,11 @@ typedef struct { unsigned num_waiters; } AioWait; +typedef struct { + struct QEMUTimer *timer; + int64_t interval; +} AioWaitTimer; + extern AioWait global_aio_wait; /** @@ -99,6 +106,55 @@ extern AioWait global_aio_wait; qatomic_dec(&wait_->num_waiters); \ waited_; }) +/** + * AIO_WAIT_WHILE_TIMEOUT: + * + * Refer to the implementation of AIO_WAIT_WHILE_INTERNAL, + * the timeout parameter is added. + */ +#define AIO_WAIT_WHILE_TIMEOUT(ctx, cond, timeout) ({ \ + int ret_ = 0; \ + AioWait *wait_ = &global_aio_wait; \ + AioContext *ctx_ = (ctx); \ + int64_t start_ = qemu_clock_get_ms(QEMU_CLOCK_REALTIME); \ + int64_t deadline_ = start_ + (timeout); \ + /* Ensure that the aio_poll exits periodically to check timeout. */ \ + AioWaitTimer *s_ = g_malloc0(sizeof(AioWaitTimer)); \ + s_->interval = AIO_WAIT_INTERVAL; \ + /* Increment wait_->num_waiters before evaluating cond. */ \ + qatomic_inc(&wait_->num_waiters); \ + /* Paired with smp_mb in aio_wait_kick(). */ \ + smp_mb__after_rmw(); \ + if (ctx_ && in_aio_context_home_thread(ctx_)) { \ + s_->timer = aio_timer_new(ctx_, QEMU_CLOCK_REALTIME, \ + SCALE_MS, aio_wait_timer_retry, s_); \ + aio_wait_timer_retry(s_); \ + while ((cond)) { \ + aio_poll(ctx_, true); \ + if (qemu_clock_get_ms(QEMU_CLOCK_REALTIME) > deadline_) { \ + ret_ = -ETIMEDOUT; \ + break; \ + } \ + } \ + } else { \ + s_->timer = aio_timer_new(qemu_get_aio_context(), \ + QEMU_CLOCK_REALTIME, SCALE_MS, aio_wait_timer_retry, s_); \ + aio_wait_timer_retry(s_); \ + while ((cond)) { \ + assert(qemu_get_current_aio_context() == \ + qemu_get_aio_context()); \ + aio_poll(qemu_get_aio_context(), true); \ + if (qemu_clock_get_ms(QEMU_CLOCK_REALTIME) > deadline_) { \ + ret_ = -ETIMEDOUT; \ + break; \ + } \ + } \ + } \ + qatomic_dec(&wait_->num_waiters); \ + timer_free(s_->timer); \ + g_free(s_); \ + ret_; }) + #define AIO_WAIT_WHILE(ctx, cond) \ AIO_WAIT_WHILE_INTERNAL(ctx, cond) @@ -149,4 +205,6 @@ static inline bool in_aio_context_home_thread(AioContext *ctx) } } +void aio_wait_timer_retry(void *opaque); + #endif /* QEMU_AIO_WAIT_H */ diff --git a/include/block/block-io.h b/include/block/block-io.h index b49e0537dd..84f92d2b09 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -354,6 +354,11 @@ bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, AIO_WAIT_WHILE(bdrv_get_aio_context(bs_), \ cond); }) +#define BDRV_POLL_WHILE_TIMEOUT(bs, cond, timeout) ({ \ + BlockDriverState *bs_ = (bs); \ + AIO_WAIT_WHILE_TIMEOUT(bdrv_get_aio_context(bs_), \ + cond, timeout); }) + void bdrv_drain(BlockDriverState *bs); int co_wrapper_mixed_bdrv_rdlock @@ -431,6 +436,8 @@ bdrv_drain_poll(BlockDriverState *bs, BdrvChild *ignore_parent, */ void bdrv_drained_begin(BlockDriverState *bs); +int bdrv_drained_begin_timeout(BlockDriverState *bs, int64_t timeout_ms); + /** * bdrv_do_drained_begin_quiesce: * diff --git a/util/aio-wait.c b/util/aio-wait.c index b5336cf5fd..9aed165529 100644 --- a/util/aio-wait.c +++ b/util/aio-wait.c @@ -84,3 +84,10 @@ void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque) aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data); AIO_WAIT_WHILE_UNLOCKED(NULL, !data.done); } + +void aio_wait_timer_retry(void *opaque) +{ + AioWaitTimer *s = opaque; + + timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + s->interval); +} -- 2.33.0