new file mode 100644
@@ -0,0 +1,67 @@
+/*
+ * reqlist API
+ *
+ * Copyright (C) 2013 Proxmox Server Solutions
+ * Copyright (c) 2021 Virtuozzo International GmbH.
+ *
+ * Authors:
+ * Dietmar Maurer (dietmar@proxmox.com)
+ * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef REQLIST_H
+#define REQLIST_H
+
+#include "qemu/coroutine.h"
+
+/*
+ * The API is not thread-safe and shouldn't be. The struct is public to be part
+ * of other structures and protected by third-party locks, see
+ * block/block-copy.c for example.
+ */
+
+typedef struct BlockReq {
+ int64_t offset;
+ int64_t bytes;
+
+ CoQueue wait_queue; /* coroutines blocked on this req */
+ QLIST_ENTRY(BlockReq) list;
+} BlockReq;
+
+typedef QLIST_HEAD(, BlockReq) BlockReqList;
+
+/*
+ * Initialize new request and add it to the list. Caller must be sure that
+ * there are no conflicting requests in the list.
+ */
+void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset,
+ int64_t bytes);
+/* Search for request in the list intersecting with @offset/@bytes area. */
+BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset,
+ int64_t bytes);
+
+/*
+ * If there are no intersecting requests return false. Otherwise, wait for the
+ * first found intersecting request to finish and return true.
+ *
+ * @lock is passed to qemu_co_queue_wait()
+ * False return value proves that lock was released at no point.
+ */
+bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset,
+ int64_t bytes, CoMutex *lock);
+
+/*
+ * Shrink request and wake all waiting coroutines (maybe some of them are not
+ * intersecting with shrunk request).
+ */
+void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes);
+
+/*
+ * Remove request and wake all waiting coroutines. Do not release any memory.
+ */
+void coroutine_fn reqlist_remove_req(BlockReq *req);
+
+#endif /* REQLIST_H */
@@ -17,6 +17,7 @@
#include "trace.h"
#include "qapi/error.h"
#include "block/block-copy.h"
+#include "block/reqlist.h"
#include "sysemu/block-backend.h"
#include "qemu/units.h"
#include "qemu/coroutine.h"
@@ -83,7 +84,6 @@ typedef struct BlockCopyTask {
*/
BlockCopyState *s;
BlockCopyCallState *call_state;
- int64_t offset;
/*
* @method can also be set again in the while loop of
* block_copy_dirty_clusters(), but it is never accessed concurrently
@@ -94,21 +94,17 @@ typedef struct BlockCopyTask {
BlockCopyMethod method;
/*
- * Fields whose state changes throughout the execution
- * Protected by lock in BlockCopyState.
+ * Generally, req is protected by lock in BlockCopyState, Still req.offset
+ * is only set on task creation, so may be read concurrently after creation.
+ * req.bytes is changed at most once, and need only protecting the case of
+ * parallel read while updating @bytes value in block_copy_task_shrink().
*/
- CoQueue wait_queue; /* coroutines blocked on this task */
- /*
- * Only protect the case of parallel read while updating @bytes
- * value in block_copy_task_shrink().
- */
- int64_t bytes;
- QLIST_ENTRY(BlockCopyTask) list;
+ BlockReq req;
} BlockCopyTask;
static int64_t task_end(BlockCopyTask *task)
{
- return task->offset + task->bytes;
+ return task->req.offset + task->req.bytes;
}
typedef struct BlockCopyState {
@@ -136,7 +132,7 @@ typedef struct BlockCopyState {
CoMutex lock;
int64_t in_flight_bytes;
BlockCopyMethod method;
- QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */
+ BlockReqList reqs;
QLIST_HEAD(, BlockCopyCallState) calls;
/*
* skip_unallocated:
@@ -160,42 +156,6 @@ typedef struct BlockCopyState {
RateLimit rate_limit;
} BlockCopyState;
-/* Called with lock held */
-static BlockCopyTask *find_conflicting_task(BlockCopyState *s,
- int64_t offset, int64_t bytes)
-{
- BlockCopyTask *t;
-
- QLIST_FOREACH(t, &s->tasks, list) {
- if (offset + bytes > t->offset && offset < t->offset + t->bytes) {
- return t;
- }
- }
-
- return NULL;
-}
-
-/*
- * If there are no intersecting tasks return false. Otherwise, wait for the
- * first found intersecting tasks to finish and return true.
- *
- * Called with lock held. May temporary release the lock.
- * Return value of 0 proves that lock was NOT released.
- */
-static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t offset,
- int64_t bytes)
-{
- BlockCopyTask *task = find_conflicting_task(s, offset, bytes);
-
- if (!task) {
- return false;
- }
-
- qemu_co_queue_wait(&task->wait_queue, &s->lock);
-
- return true;
-}
-
/* Called with lock held */
static int64_t block_copy_chunk_size(BlockCopyState *s)
{
@@ -239,7 +199,7 @@ block_copy_task_create(BlockCopyState *s, BlockCopyCallState *call_state,
bytes = QEMU_ALIGN_UP(bytes, s->cluster_size);
/* region is dirty, so no existent tasks possible in it */
- assert(!find_conflicting_task(s, offset, bytes));
+ assert(!reqlist_find_conflict(&s->reqs, offset, bytes));
bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
s->in_flight_bytes += bytes;
@@ -249,12 +209,9 @@ block_copy_task_create(BlockCopyState *s, BlockCopyCallState *call_state,
.task.func = block_copy_task_entry,
.s = s,
.call_state = call_state,
- .offset = offset,
- .bytes = bytes,
.method = s->method,
};
- qemu_co_queue_init(&task->wait_queue);
- QLIST_INSERT_HEAD(&s->tasks, task, list);
+ reqlist_init_req(&s->reqs, &task->req, offset, bytes);
return task;
}
@@ -270,34 +227,34 @@ static void coroutine_fn block_copy_task_shrink(BlockCopyTask *task,
int64_t new_bytes)
{
QEMU_LOCK_GUARD(&task->s->lock);
- if (new_bytes == task->bytes) {
+ if (new_bytes == task->req.bytes) {
return;
}
- assert(new_bytes > 0 && new_bytes < task->bytes);
+ assert(new_bytes > 0 && new_bytes < task->req.bytes);
- task->s->in_flight_bytes -= task->bytes - new_bytes;
+ task->s->in_flight_bytes -= task->req.bytes - new_bytes;
bdrv_set_dirty_bitmap(task->s->copy_bitmap,
- task->offset + new_bytes, task->bytes - new_bytes);
+ task->req.offset + new_bytes,
+ task->req.bytes - new_bytes);
- task->bytes = new_bytes;
- qemu_co_queue_restart_all(&task->wait_queue);
+ reqlist_shrink_req(&task->req, new_bytes);
}
static void coroutine_fn block_copy_task_end(BlockCopyTask *task, int ret)
{
QEMU_LOCK_GUARD(&task->s->lock);
- task->s->in_flight_bytes -= task->bytes;
+ task->s->in_flight_bytes -= task->req.bytes;
if (ret < 0) {
- bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->offset, task->bytes);
+ bdrv_set_dirty_bitmap(task->s->copy_bitmap, task->req.offset,
+ task->req.bytes);
}
- QLIST_REMOVE(task, list);
if (task->s->progress) {
progress_set_remaining(task->s->progress,
bdrv_get_dirty_count(task->s->copy_bitmap) +
task->s->in_flight_bytes);
}
- qemu_co_queue_restart_all(&task->wait_queue);
+ reqlist_remove_req(&task->req);
}
void block_copy_state_free(BlockCopyState *s)
@@ -450,7 +407,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
ratelimit_init(&s->rate_limit);
qemu_co_mutex_init(&s->lock);
- QLIST_INIT(&s->tasks);
+ QLIST_INIT(&s->reqs);
QLIST_INIT(&s->calls);
return s;
@@ -483,7 +440,7 @@ static coroutine_fn int block_copy_task_run(AioTaskPool *pool,
aio_task_pool_wait_slot(pool);
if (aio_task_pool_status(pool) < 0) {
- co_put_to_shres(task->s->mem, task->bytes);
+ co_put_to_shres(task->s->mem, task->req.bytes);
block_copy_task_end(task, -ECANCELED);
g_free(task);
return -ECANCELED;
@@ -596,7 +553,8 @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
BlockCopyMethod method = t->method;
int ret;
- ret = block_copy_do_copy(s, t->offset, t->bytes, &method, &error_is_read);
+ ret = block_copy_do_copy(s, t->req.offset, t->req.bytes, &method,
+ &error_is_read);
WITH_QEMU_LOCK_GUARD(&s->lock) {
if (s->method == t->method) {
@@ -609,10 +567,10 @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
t->call_state->error_is_read = error_is_read;
}
} else if (s->progress) {
- progress_work_done(s->progress, t->bytes);
+ progress_work_done(s->progress, t->req.bytes);
}
}
- co_put_to_shres(s->mem, t->bytes);
+ co_put_to_shres(s->mem, t->req.bytes);
block_copy_task_end(t, ret);
return ret;
@@ -771,22 +729,22 @@ block_copy_dirty_clusters(BlockCopyCallState *call_state)
trace_block_copy_skip_range(s, offset, bytes);
break;
}
- if (task->offset > offset) {
- trace_block_copy_skip_range(s, offset, task->offset - offset);
+ if (task->req.offset > offset) {
+ trace_block_copy_skip_range(s, offset, task->req.offset - offset);
}
found_dirty = true;
- ret = block_copy_block_status(s, task->offset, task->bytes,
+ ret = block_copy_block_status(s, task->req.offset, task->req.bytes,
&status_bytes);
assert(ret >= 0); /* never fail */
- if (status_bytes < task->bytes) {
+ if (status_bytes < task->req.bytes) {
block_copy_task_shrink(task, status_bytes);
}
if (qatomic_read(&s->skip_unallocated) &&
!(ret & BDRV_BLOCK_ALLOCATED)) {
block_copy_task_end(task, 0);
- trace_block_copy_skip_range(s, task->offset, task->bytes);
+ trace_block_copy_skip_range(s, task->req.offset, task->req.bytes);
offset = task_end(task);
bytes = end - offset;
g_free(task);
@@ -807,11 +765,11 @@ block_copy_dirty_clusters(BlockCopyCallState *call_state)
}
}
- ratelimit_calculate_delay(&s->rate_limit, task->bytes);
+ ratelimit_calculate_delay(&s->rate_limit, task->req.bytes);
- trace_block_copy_process(s, task->offset);
+ trace_block_copy_process(s, task->req.offset);
- co_get_from_shres(s->mem, task->bytes);
+ co_get_from_shres(s->mem, task->req.bytes);
offset = task_end(task);
bytes = end - offset;
@@ -879,8 +837,8 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
* Check that there is no task we still need to
* wait to complete
*/
- ret = block_copy_wait_one(s, call_state->offset,
- call_state->bytes);
+ ret = reqlist_wait_one(&s->reqs, call_state->offset,
+ call_state->bytes, &s->lock);
if (ret == 0) {
/*
* No pending tasks, but check again the bitmap in this
@@ -888,7 +846,7 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
* between this and the critical section in
* block_copy_dirty_clusters().
*
- * block_copy_wait_one return value 0 also means that it
+ * reqlist_wait_one return value 0 also means that it
* didn't release the lock. So, we are still in the same
* critical section, not interrupted by any concurrent
* access to state.
new file mode 100644
@@ -0,0 +1,76 @@
+/*
+ * reqlist API
+ *
+ * Copyright (C) 2013 Proxmox Server Solutions
+ * Copyright (c) 2021 Virtuozzo International GmbH.
+ *
+ * Authors:
+ * Dietmar Maurer (dietmar@proxmox.com)
+ * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include "block/reqlist.h"
+
+void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset,
+ int64_t bytes)
+{
+ assert(!reqlist_find_conflict(reqs, offset, bytes));
+
+ *req = (BlockReq) {
+ .offset = offset,
+ .bytes = bytes,
+ };
+ qemu_co_queue_init(&req->wait_queue);
+ QLIST_INSERT_HEAD(reqs, req, list);
+}
+
+BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset,
+ int64_t bytes)
+{
+ BlockReq *r;
+
+ QLIST_FOREACH(r, reqs, list) {
+ if (offset + bytes > r->offset && offset < r->offset + r->bytes) {
+ return r;
+ }
+ }
+
+ return NULL;
+}
+
+bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset,
+ int64_t bytes, CoMutex *lock)
+{
+ BlockReq *r = reqlist_find_conflict(reqs, offset, bytes);
+
+ if (!r) {
+ return false;
+ }
+
+ qemu_co_queue_wait(&r->wait_queue, lock);
+
+ return true;
+}
+
+void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes)
+{
+ if (new_bytes == req->bytes) {
+ return;
+ }
+
+ assert(new_bytes > 0 && new_bytes < req->bytes);
+
+ req->bytes = new_bytes;
+ qemu_co_queue_restart_all(&req->wait_queue);
+}
+
+void coroutine_fn reqlist_remove_req(BlockReq *req)
+{
+ QLIST_REMOVE(req, list);
+ qemu_co_queue_restart_all(&req->wait_queue);
+}
@@ -2515,7 +2515,9 @@ F: block/stream.c
F: block/mirror.c
F: qapi/job.json
F: block/block-copy.c
-F: include/block/block-copy.c
+F: include/block/block-copy.h
+F: block/reqlist.c
+F: include/block/reqlist.h
F: block/copy-before-write.h
F: block/copy-before-write.c
F: include/block/aio_task.h
@@ -32,6 +32,7 @@ block_ss.add(files(
'qcow2.c',
'quorum.c',
'raw-format.c',
+ 'reqlist.c',
'snapshot.c',
'throttle-groups.c',
'throttle.c',