| Message ID | 20210518100757.31243-6-eesposit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block-copy: protect block-copy internal structures | expand |
18.05.2021 13:07, Emanuele Giuseppe Esposito wrote: > As for BlockCopyTask, add a lock to protect BlockCopyCallState > ret and sleep_state fields. Also move ret, finished and cancelled > in the OUT fields of BlockCopyCallState. > > Here a QemuMutex is used to protect QemuCoSleep field, since it > can be concurrently invoked also from outside threads. > > .finished, .cancelled and reads to .ret and .error_is_read will be > protected in the following patch. > > .sleep state is handled in the series "coroutine: new sleep/wake API" Could we live with one mutex for all needs? Why to add one more? > > Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> > --- > block/block-copy.c | 27 +++++++++++++++++++-------- > 1 file changed, 19 insertions(+), 8 deletions(-) > > diff --git a/block/block-copy.c b/block/block-copy.c > index 3a949fab64..d5ed5932b0 100644 > --- a/block/block-copy.c > +++ b/block/block-copy.c > @@ -55,13 +55,14 @@ typedef struct BlockCopyCallState { > QLIST_ENTRY(BlockCopyCallState) list; > > /* State */ > - int ret; > bool finished; > - QemuCoSleep sleep; > - bool cancelled; > + QemuCoSleep sleep; /* TODO: protect API with a lock */ > > /* OUT parameters */ > + bool cancelled; > + /* Fields protected by calls_lock in BlockCopyState */ > bool error_is_read; > + int ret; > } BlockCopyCallState; > > typedef struct BlockCopyTask { > @@ -110,6 +111,7 @@ typedef struct BlockCopyState { > BlockCopyMethod method; > CoMutex tasks_lock; > QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */ > + QemuMutex calls_lock; > QLIST_HEAD(, BlockCopyCallState) calls; > /* State fields that use a thread-safe API */ > BdrvDirtyBitmap *copy_bitmap; > @@ -289,6 +291,7 @@ void block_copy_state_free(BlockCopyState *s) > } > > ratelimit_destroy(&s->rate_limit); > + qemu_mutex_destroy(&s->calls_lock); > bdrv_release_dirty_bitmap(s->copy_bitmap); > shres_destroy(s->mem); > g_free(s); > @@ -349,6 +352,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, > > ratelimit_init(&s->rate_limit); > qemu_co_mutex_init(&s->tasks_lock); > + qemu_mutex_init(&s->calls_lock); > QLIST_INIT(&s->tasks); > QLIST_INIT(&s->calls); > > @@ -492,11 +496,14 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) > > ret = block_copy_do_copy(t->s, t->offset, t->bytes, t->zeroes, > &error_is_read); > - if (ret < 0 && !t->call_state->ret) { > - t->call_state->ret = ret; > - t->call_state->error_is_read = error_is_read; > - } else { > - progress_work_done(t->s->progress, t->bytes); > + > + WITH_QEMU_LOCK_GUARD(&t->s->calls_lock) { > + if (ret < 0 && !t->call_state->ret) { > + t->call_state->ret = ret; > + t->call_state->error_is_read = error_is_read; > + } else { > + progress_work_done(t->s->progress, t->bytes); > + } > } > co_put_to_shres(t->s->mem, t->bytes); > block_copy_task_end(t, ret); > @@ -740,7 +747,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) > { > int ret; > > + qemu_mutex_lock(&call_state->s->calls_lock); > QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list); > + qemu_mutex_unlock(&call_state->s->calls_lock); > > do { > ret = block_copy_dirty_clusters(call_state); > @@ -767,7 +776,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) > call_state->cb(call_state->cb_opaque); > } > > + qemu_mutex_lock(&call_state->s->calls_lock); > QLIST_REMOVE(call_state, list); > + qemu_mutex_unlock(&call_state->s->calls_lock); > > return ret; > } >
On 20/05/21 17:30, Vladimir Sementsov-Ogievskiy wrote: > 18.05.2021 13:07, Emanuele Giuseppe Esposito wrote: >> As for BlockCopyTask, add a lock to protect BlockCopyCallState >> ret and sleep_state fields. Also move ret, finished and cancelled >> in the OUT fields of BlockCopyCallState. >> >> Here a QemuMutex is used to protect QemuCoSleep field, since it >> can be concurrently invoked also from outside threads. >> >> .finished, .cancelled and reads to .ret and .error_is_read will be >> protected in the following patch. >> >> .sleep state is handled in the series "coroutine: new sleep/wake API" > > Could we live with one mutex for all needs? Why to add one more? This patch should just go away; the QemuMutex will not be needed once QemuCoSleep is thread safe, while right now it is still racy. Paolo
On 21/05/2021 17:01, Paolo Bonzini wrote: > On 20/05/21 17:30, Vladimir Sementsov-Ogievskiy wrote: >> 18.05.2021 13:07, Emanuele Giuseppe Esposito wrote: >>> As for BlockCopyTask, add a lock to protect BlockCopyCallState >>> ret and sleep_state fields. Also move ret, finished and cancelled >>> in the OUT fields of BlockCopyCallState. >>> >>> Here a QemuMutex is used to protect QemuCoSleep field, since it >>> can be concurrently invoked also from outside threads. Actually I don't even protect it here, I should have deleted the above line. I left a TODO for the QemuCoSleep field. >>> >>> .finished, .cancelled and reads to .ret and .error_is_read will be >>> protected in the following patch. >>> >>> .sleep state is handled in the series "coroutine: new sleep/wake API" >> >> Could we live with one mutex for all needs? Why to add one more? > > This patch should just go away; the QemuMutex will not be needed once > QemuCoSleep is thread safe, while right now it is still racy. At this point, I would just rename the other lock (tasks_lock) in "lock" or "state_lock", and substitute it in the calls_lock usages of this patch. Depending on how it comes out, I may merge this with the previous patch. Thank you, Emanuele
On 25/05/21 12:58, Emanuele Giuseppe Esposito wrote: > > At this point, I would just rename the other lock (tasks_lock) in "lock" > or "state_lock", and substitute it in the calls_lock usages of this > patch. Depending on how it comes out, I may merge this with the previous > patch. Renaming the lock is a good idea indeed. Paolo
On 18/05/21 12:07, Emanuele Giuseppe Esposito wrote: > + qemu_mutex_lock(&call_state->s->calls_lock); > QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list); > + qemu_mutex_unlock(&call_state->s->calls_lock); Let's just use tasks_lock here (maybe even rename it to just "lock"). Paolo
diff --git a/block/block-copy.c b/block/block-copy.c index 3a949fab64..d5ed5932b0 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -55,13 +55,14 @@ typedef struct BlockCopyCallState { QLIST_ENTRY(BlockCopyCallState) list; /* State */ - int ret; bool finished; - QemuCoSleep sleep; - bool cancelled; + QemuCoSleep sleep; /* TODO: protect API with a lock */ /* OUT parameters */ + bool cancelled; + /* Fields protected by calls_lock in BlockCopyState */ bool error_is_read; + int ret; } BlockCopyCallState; typedef struct BlockCopyTask { @@ -110,6 +111,7 @@ typedef struct BlockCopyState { BlockCopyMethod method; CoMutex tasks_lock; QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */ + QemuMutex calls_lock; QLIST_HEAD(, BlockCopyCallState) calls; /* State fields that use a thread-safe API */ BdrvDirtyBitmap *copy_bitmap; @@ -289,6 +291,7 @@ void block_copy_state_free(BlockCopyState *s) } ratelimit_destroy(&s->rate_limit); + qemu_mutex_destroy(&s->calls_lock); bdrv_release_dirty_bitmap(s->copy_bitmap); shres_destroy(s->mem); g_free(s); @@ -349,6 +352,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, ratelimit_init(&s->rate_limit); qemu_co_mutex_init(&s->tasks_lock); + qemu_mutex_init(&s->calls_lock); QLIST_INIT(&s->tasks); QLIST_INIT(&s->calls); @@ -492,11 +496,14 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) ret = block_copy_do_copy(t->s, t->offset, t->bytes, t->zeroes, &error_is_read); - if (ret < 0 && !t->call_state->ret) { - t->call_state->ret = ret; - t->call_state->error_is_read = error_is_read; - } else { - progress_work_done(t->s->progress, t->bytes); + + WITH_QEMU_LOCK_GUARD(&t->s->calls_lock) { + if (ret < 0 && !t->call_state->ret) { + t->call_state->ret = ret; + t->call_state->error_is_read = error_is_read; + } else { + progress_work_done(t->s->progress, t->bytes); + } } co_put_to_shres(t->s->mem, t->bytes); block_copy_task_end(t, ret); @@ -740,7 +747,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) { int ret; + qemu_mutex_lock(&call_state->s->calls_lock); QLIST_INSERT_HEAD(&call_state->s->calls, call_state, list); + qemu_mutex_unlock(&call_state->s->calls_lock); do { ret = block_copy_dirty_clusters(call_state); @@ -767,7 +776,9 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state) call_state->cb(call_state->cb_opaque); } + qemu_mutex_lock(&call_state->s->calls_lock); QLIST_REMOVE(call_state, list); + qemu_mutex_unlock(&call_state->s->calls_lock); return ret; }
As for BlockCopyTask, add a lock to protect BlockCopyCallState ret and sleep_state fields. Also move ret, finished and cancelled in the OUT fields of BlockCopyCallState. Here a QemuMutex is used to protect QemuCoSleep field, since it can be concurrently invoked also from outside threads. .finished, .cancelled and reads to .ret and .error_is_read will be protected in the following patch. .sleep state is handled in the series "coroutine: new sleep/wake API" Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> --- block/block-copy.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-)