[PATCH v3 5/7] block/block-copy: block_copy(): add timeout_ns parameter

[Vladimir Sementsov-Ogievskiy]

Add possibility to limit block_copy() call in time. To be used in the
next commit.

As timed-out block_copy() call will continue in background anyway (we
can't immediately cancel IO operation), it's important also give user a
possibility to pass a callback, to do some additional actions on
block-copy call finish.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@openvz.org>
---
 include/block/block-copy.h |  4 +++-
 block/block-copy.c         | 33 ++++++++++++++++++++++++++-------
 block/copy-before-write.c  |  2 +-
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index 68bbd344b2..ba0b425d78 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -40,7 +40,9 @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
                                      int64_t offset, int64_t *count);
 
 int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
-                            bool ignore_ratelimit);
+                            bool ignore_ratelimit, uint64_t timeout_ns,
+                            BlockCopyAsyncCallbackFunc cb,
+                            void *cb_opaque);
 
 /*
  * Run block-copy in a coroutine, create corresponding BlockCopyCallState
diff --git a/block/block-copy.c b/block/block-copy.c
index ec46775ea5..bb947afdda 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -883,23 +883,42 @@ static int coroutine_fn 
block_copy_common(BlockCopyCallState *call_state)
     return ret;
 }
 
+static void coroutine_fn block_copy_async_co_entry(void *opaque)
+{
+    block_copy_common(opaque);
+}
+
 int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
-                            bool ignore_ratelimit)
+                            bool ignore_ratelimit, uint64_t timeout_ns,
+                            BlockCopyAsyncCallbackFunc cb,
+                            void *cb_opaque)
 {
-    BlockCopyCallState call_state = {
+    int ret;
+    BlockCopyCallState *call_state = g_new(BlockCopyCallState, 1);
+
+    *call_state = (BlockCopyCallState) {
         .s = s,
         .offset = start,
         .bytes = bytes,
         .ignore_ratelimit = ignore_ratelimit,
         .max_workers = BLOCK_COPY_MAX_WORKERS,
+        .cb = cb,
+        .cb_opaque = cb_opaque,
     };
 
-    return block_copy_common(&call_state);
-}
+    ret = qemu_co_timeout(block_copy_async_co_entry, call_state, timeout_ns,
+                          g_free);
+    if (ret < 0) {
+        assert(ret == -ETIMEDOUT);
+        block_copy_call_cancel(call_state);
+        /* call_state will be freed by running coroutine. */
+        return ret;
+    }
 
-static void coroutine_fn block_copy_async_co_entry(void *opaque)
-{
-    block_copy_common(opaque);
+    ret = call_state->ret;
+    g_free(call_state);
+
+    return ret;
 }
 
 BlockCopyCallState *block_copy_async(BlockCopyState *s,
diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index ffb05d22f8..b7487e4ffe 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -111,7 +111,7 @@ static coroutine_fn int 
cbw_do_copy_before_write(BlockDriverState *bs,
     off = QEMU_ALIGN_DOWN(offset, cluster_size);
     end = QEMU_ALIGN_UP(offset + bytes, cluster_size);
 
-    ret = block_copy(s->bcs, off, end - off, true);
+    ret = block_copy(s->bcs, off, end - off, true, 0, NULL, NULL);
     if (ret < 0 && s->on_cbw_error == ON_CBW_ERROR_BREAK_GUEST_WRITE) {
         return ret;
     }
-- 
2.35.1