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Drain fixes and cleanups, part 2

PATCH In review Kevin Wolf 2 participants 27 messages Dec 21, 2017 – Jan 8, 2018 Block layer

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Kevin Wolf

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#0 lore raw

v2 cover Drain fixes and cleanups, part 2

This is the second part of my work to fix drain and hopefully to prevent it from attracting bugs as much as it did in the past. There is definitely at least a third part coming after this, see below.

In this series, the following improvments are made:
* Fix several bugs and inconsistencies
* Create lots of unit tests for the drain functions
* Introduce bdrv_subtree_drained_begin/end() to drain a whole subtree rather than only a single node
* Use this to make bdrv_reopen() safe (graph changes in callbacks called during its internal bdrv_drain_all() frequently broke it)

Planned for part three: Make graph modifications in callbacks safe by avoiding BDRV_POLL_WHILE() calls while we're recursing through the graph. We can recurse before BDRV_POLL_WHILE(), after it or while evaluating its condition, but never call any callbacks while we're iterating child or parent lists.

v2:
- Improved the commit message of patch 3 [Fam]
- Split the coroutine test cases in individual parts [Paolo]
- Export bdrv_(un)apply_subtree_drain rather than bdrv_do_drained_begin/end() [Paolo]

Fam Zheng (1):
block: Remove unused bdrv_requests_pending

Kevin Wolf (18):
block: Assert drain_all is only called from main AioContext
block: Make bdrv_drain() driver callbacks non-recursive
test-bdrv-drain: Test callback for bdrv_drain
test-bdrv-drain: Test bs->quiesce_counter
blockjob: Pause job on draining any job BDS
test-bdrv-drain: Test drain vs. block jobs
block: Don't block_job_pause_all() in bdrv_drain_all()
block: Nested drain_end must still call callbacks
test-bdrv-drain: Test nested drain sections
block: Don't notify parents in drain call chain
block: Add bdrv_subtree_drained_begin/end()
test-bdrv-drain: Tests for bdrv_subtree_drain
test-bdrv-drain: Test behaviour in coroutine context
test-bdrv-drain: Recursive draining with multiple parents
block: Allow graph changes in subtree drained section
test-bdrv-drain: Test graph changes in drained section
commit: Simplify reopen of base
block: Keep nodes drained between reopen_queue/multiple

 include/block/block.h     |  15 +-
 include/block/block_int.h |   6 +-
 block.c                   |  66 ++++--
 block/commit.c            |   8 +-
 block/io.c                | 151 +++++++++----
 block/replication.c       |   6 +
 blockjob.c                |  22 +-
 qemu-io-cmds.c            |   3 +
 tests/test-bdrv-drain.c   | 528 +++++++++++++++++++++++++++++++++++++++++++++-
 9 files changed, 717 insertions(+), 88 deletions(-)
Signature · 1 line
2.13.6
author
#1 lore raw

PATCH v2 1/19 block: Remove unused bdrv_requests_pending

From: Fam Zheng <[email protected]>

Signed-off-by Fam Zheng <[email protected]>
Signed-off-by Kevin Wolf <[email protected]>
---
 include/block/block_int.h |  1 -
 block/io.c                | 18 ------------------
 2 files changed, 19 deletions(-)
include/block/block_int.h +0 -1
index a5482775ec..e107163594 100644
@@ -1045,7 +1045,6 @@ bool blk_dev_is_tray_open(BlockBackend *blk);
 bool blk_dev_is_medium_locked(BlockBackend *blk);
 
 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes);
-bool bdrv_requests_pending(BlockDriverState *bs);
 
 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in);
block/io.c +0 -18
index 1e92d2e5b2..cf780c3cb0 100644
@@ -134,24 +134,6 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs)
     assert(old >= 1);
 }
 
-/* Check if any requests are in-flight (including throttled requests) */
-bool bdrv_requests_pending(BlockDriverState *bs)
-{
-    BdrvChild *child;
-
-    if (atomic_read(&bs->in_flight)) {
-        return true;
-    }
-
-    QLIST_FOREACH(child, &bs->children, next) {
-        if (bdrv_requests_pending(child->bs)) {
-            return true;
-        }
-    }
-
-    return false;
-}
-
 typedef struct {
     Coroutine *co;
     BlockDriverState *bs;
Signature · 1 line
2.13.6
author
#3 lore raw

PATCH v2 2/19 block: Assert drain_all is only called from main AioContext

In reply to Kevin Wolf
Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Fam Zheng <[email protected]>
---
 block/io.c | 6 ++++++
 1 file changed, 6 insertions(+)
block/io.c +6 -0
index cf780c3cb0..b94740b8ff 100644
@@ -330,6 +330,12 @@ void bdrv_drain_all_begin(void)
     BdrvNextIterator it;
     GSList *aio_ctxs = NULL, *ctx;
 
+    /* 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. */
+    assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+
     block_job_pause_all();
 
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
Signature · 1 line
2.13.6
Reviewed-by on v2 2/19
#4 lore raw

Re: [Qemu-devel] [Qemu-block] [PATCH v2 02/19] block: Assert drain_all is only called from main AioContext

Quoted 11 lines · Kevin Wolf
Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Fam Zheng <[email protected]>
---
 block/io.c | 6 ++++++
 1 file changed, 6 insertions(+)
block/io.c +0 -0
index cf780c3cb0..b94740b8ff 100644

block/io.c void bdrv_drain_all_begin(void) · line 339

Quoted 10 lines
block/io.c +6 -0
@@ -330,6 +330,12 @@ void bdrv_drain_all_begin(void)
     BdrvNextIterator it;
     GSList *aio_ctxs = NULL, *ctx;
 
+    /* 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. */
+    assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+
     block_job_pause_all();
Reviewed-by Alberto Garcia <[email protected]>

Berto

author
#5 lore raw

PATCH v2 3/19 block: Make bdrv_drain() driver callbacks non-recursive

In reply to Kevin Wolf

bdrv_drained_begin() doesn't increase bs->quiesce_counter recursively and also doesn't notify other parent nodes of children, which both means that the child nodes are not actually drained, and bdrv_drained_begin() is providing useful functionality only on a single node.

To keep things consistent, we also shouldn't call the block driver callbacks recursively.

A proper recursive drain version that provides an actually working drained section for child nodes will be introduced later.

Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Fam Zheng <[email protected]>
---
 block/io.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)
block/io.c +9 -7
index b94740b8ff..91a52e2d82 100644
@@ -158,7 +158,7 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
 }
 
 /* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */
-static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)
+static void bdrv_drain_invoke(BlockDriverState *bs, bool begin, bool recursive)
 {
     BdrvChild *child, *tmp;
     BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin};

@@ -172,8 +172,10 @@ static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)
     bdrv_coroutine_enter(bs, data.co);
     BDRV_POLL_WHILE(bs, !data.done);
 
-    QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {
-        bdrv_drain_invoke(child->bs, begin);
+    if (recursive) {
+        QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {
+            bdrv_drain_invoke(child->bs, begin, true);
+        }
     }
 }
 

@@ -265,7 +267,7 @@ void bdrv_drained_begin(BlockDriverState *bs)
         bdrv_parent_drained_begin(bs);
     }
 
-    bdrv_drain_invoke(bs, true);
+    bdrv_drain_invoke(bs, true, false);
     bdrv_drain_recurse(bs);
 }
 

@@ -281,7 +283,7 @@ void bdrv_drained_end(BlockDriverState *bs)
     }
 
     /* Re-enable things in child-to-parent order */
-    bdrv_drain_invoke(bs, false);
+    bdrv_drain_invoke(bs, false, false);
     bdrv_parent_drained_end(bs);
     aio_enable_external(bdrv_get_aio_context(bs));
 }

@@ -345,7 +347,7 @@ void bdrv_drain_all_begin(void)
         aio_context_acquire(aio_context);
         aio_disable_external(aio_context);
         bdrv_parent_drained_begin(bs);
-        bdrv_drain_invoke(bs, true);
+        bdrv_drain_invoke(bs, true, true);
         aio_context_release(aio_context);
 
         if (!g_slist_find(aio_ctxs, aio_context)) {

@@ -388,7 +390,7 @@ void bdrv_drain_all_end(void)
 
         /* Re-enable things in child-to-parent order */
         aio_context_acquire(aio_context);
-        bdrv_drain_invoke(bs, false);
+        bdrv_drain_invoke(bs, false, true);
         bdrv_parent_drained_end(bs);
         aio_enable_external(aio_context);
         aio_context_release(aio_context);
Signature · 1 line
2.13.6
author
#6 lore raw

PATCH v2 4/19 test-bdrv-drain: Test callback for bdrv_drain

In reply to Kevin Wolf

The existing test is for bdrv_drain_all_begin/end() only. Generalise the test case so that it can be run for the other variants as well. At the moment this is only bdrv_drain_begin/end(), but in a while, we'll add another one.

Also, add a backing file to the test node to test whether the operations work recursively.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 62 insertions(+), 7 deletions(-)
tests/test-bdrv-drain.c +62 -7
index 67541438c1..c05203bba8 100644
@@ -71,6 +71,8 @@ static BlockDriver bdrv_test = {
 
     .bdrv_co_drain_begin    = bdrv_test_co_drain_begin,
     .bdrv_co_drain_end      = bdrv_test_co_drain_end,
+
+    .bdrv_child_perm        = bdrv_format_default_perms,
 };
 
 static void aio_ret_cb(void *opaque, int ret)

@@ -79,11 +81,34 @@ static void aio_ret_cb(void *opaque, int ret)
     *aio_ret = ret;
 }
 
-static void test_drv_cb_drain_all(void)
+enum drain_type {
+    BDRV_DRAIN_ALL,
+    BDRV_DRAIN,
+};
+
+static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)
+{
+    switch (drain_type) {
+    case BDRV_DRAIN_ALL:        bdrv_drain_all_begin(); break;
+    case BDRV_DRAIN:            bdrv_drained_begin(bs); break;
+    default:                    g_assert_not_reached();
+    }
+}
+
+static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs)
+{
+    switch (drain_type) {
+    case BDRV_DRAIN_ALL:        bdrv_drain_all_end(); break;
+    case BDRV_DRAIN:            bdrv_drained_end(bs); break;
+    default:                    g_assert_not_reached();
+    }
+}
+
+static void test_drv_cb_common(enum drain_type drain_type, bool recursive)
 {
     BlockBackend *blk;
-    BlockDriverState *bs;
-    BDRVTestState *s;
+    BlockDriverState *bs, *backing;
+    BDRVTestState *s, *backing_s;
     BlockAIOCB *acb;
     int aio_ret;
 

@@ -100,12 +125,23 @@ static void test_drv_cb_drain_all(void)
     s = bs->opaque;
     blk_insert_bs(blk, bs, &error_abort);
 
+    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
+    backing_s = backing->opaque;
+    bdrv_set_backing_hd(bs, backing, &error_abort);
+
     /* Simple bdrv_drain_all_begin/end pair, check that CBs are called */
     g_assert_cmpint(s->drain_count, ==, 0);
-    bdrv_drain_all_begin();
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    do_drain_begin(drain_type, bs);
+
     g_assert_cmpint(s->drain_count, ==, 1);
-    bdrv_drain_all_end();
+    g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
+
+    do_drain_end(drain_type, bs);
+
     g_assert_cmpint(s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
 
     /* Now do the same while a request is pending */
     aio_ret = -EINPROGRESS;

@@ -114,16 +150,34 @@ static void test_drv_cb_drain_all(void)
     g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
 
     g_assert_cmpint(s->drain_count, ==, 0);
-    bdrv_drain_all_begin();
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    do_drain_begin(drain_type, bs);
+
     g_assert_cmpint(aio_ret, ==, 0);
     g_assert_cmpint(s->drain_count, ==, 1);
-    bdrv_drain_all_end();
+    g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
+
+    do_drain_end(drain_type, bs);
+
     g_assert_cmpint(s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
 
+    bdrv_unref(backing);
     bdrv_unref(bs);
     blk_unref(blk);
 }
 
+static void test_drv_cb_drain_all(void)
+{
+    test_drv_cb_common(BDRV_DRAIN_ALL, true);
+}
+
+static void test_drv_cb_drain(void)
+{
+    test_drv_cb_common(BDRV_DRAIN, false);
+}
+
 int main(int argc, char **argv)
 {
     bdrv_init();

@@ -132,6 +186,7 @@ int main(int argc, char **argv)
     g_test_init(&argc, &argv, NULL);
 
     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
+    g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
 
     return g_test_run();
 }
Signature · 1 line
2.13.6
author
#7 lore raw

PATCH v2 5/19 test-bdrv-drain: Test bs->quiesce_counter

In reply to Kevin Wolf

This is currently only working correctly for bdrv_drain(), not for bdrv_drain_all(). Leave a comment for the drain_all case, we'll address it later.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
tests/test-bdrv-drain.c +45 -0
index c05203bba8..2aa2b9aa43 100644
@@ -178,6 +178,48 @@ static void test_drv_cb_drain(void)
     test_drv_cb_common(BDRV_DRAIN, false);
 }
 
+static void test_quiesce_common(enum drain_type drain_type, bool recursive)
+{
+    BlockBackend *blk;
+    BlockDriverState *bs, *backing;
+
+    blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
+                              &error_abort);
+    blk_insert_bs(blk, bs, &error_abort);
+
+    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
+    bdrv_set_backing_hd(bs, backing, &error_abort);
+
+    g_assert_cmpint(bs->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+
+    do_drain_begin(drain_type, bs);
+
+    g_assert_cmpint(bs->quiesce_counter, ==, 1);
+    g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
+
+    do_drain_end(drain_type, bs);
+
+    g_assert_cmpint(bs->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+
+    bdrv_unref(backing);
+    bdrv_unref(bs);
+    blk_unref(blk);
+}
+
+static void test_quiesce_drain_all(void)
+{
+    // XXX drain_all doesn't quiesce
+    //test_quiesce_common(BDRV_DRAIN_ALL, true);
+}
+
+static void test_quiesce_drain(void)
+{
+    test_quiesce_common(BDRV_DRAIN, false);
+}
+
 int main(int argc, char **argv)
 {
     bdrv_init();

@@ -188,5 +230,8 @@ int main(int argc, char **argv)
     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
     g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
 
+    g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
+    g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
+
     return g_test_run();
 }
Signature · 1 line
2.13.6
author
#8 lore raw

PATCH v2 6/19 blockjob: Pause job on draining any job BDS

In reply to Kevin Wolf

Block jobs already paused themselves when their main BlockBackend entered a drained section. This is not good enough: We also want to pause a block job and may not submit new requests if, for example, the mirror target node should be drained.

This implements .drained_begin/end callbacks in child_job in order to consider all block nodes related to the job, and removes the BlockBackend callbacks which are unnecessary now because the root of the job main BlockBackend is always referenced with a child_job, too.

Signed-off-by Kevin Wolf <[email protected]>
---
 blockjob.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)
blockjob.c +9 -13
index 6173e4728c..f5cea84e73 100644
@@ -234,26 +234,23 @@ static char *child_job_get_parent_desc(BdrvChild *c)
                            job->id);
 }
 
-static const BdrvChildRole child_job = {
-    .get_parent_desc    = child_job_get_parent_desc,
-    .stay_at_node       = true,
-};
-
-static void block_job_drained_begin(void *opaque)
+static void child_job_drained_begin(BdrvChild *c)
 {
-    BlockJob *job = opaque;
+    BlockJob *job = c->opaque;
     block_job_pause(job);
 }
 
-static void block_job_drained_end(void *opaque)
+static void child_job_drained_end(BdrvChild *c)
 {
-    BlockJob *job = opaque;
+    BlockJob *job = c->opaque;
     block_job_resume(job);
 }
 
-static const BlockDevOps block_job_dev_ops = {
-    .drained_begin = block_job_drained_begin,
-    .drained_end = block_job_drained_end,
+static const BdrvChildRole child_job = {
+    .get_parent_desc    = child_job_get_parent_desc,
+    .drained_begin      = child_job_drained_begin,
+    .drained_end        = child_job_drained_end,
+    .stay_at_node       = true,
 };
 
 void block_job_remove_all_bdrv(BlockJob *job)

@@ -715,7 +712,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     block_job_add_bdrv(job, "main node", bs, 0, BLK_PERM_ALL, &error_abort);
     bs->job = job;
 
-    blk_set_dev_ops(blk, &block_job_dev_ops, job);
     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 
     QLIST_INSERT_HEAD(&block_jobs, job, job_list);
Signature · 1 line
2.13.6
Reviewed-by on v2 6/19
#9 lore raw

Re: [Qemu-devel] [Qemu-block] [PATCH v2 06/19] blockjob: Pause job on draining any job BDS

Quoted 11 lines · Kevin Wolf

Block jobs already paused themselves when their main BlockBackend entered a drained section. This is not good enough: We also want to pause a block job and may not submit new requests if, for example, the mirror target node should be drained.

This implements .drained_begin/end callbacks in child_job in order to consider all block nodes related to the job, and removes the BlockBackend callbacks which are unnecessary now because the root of the job main BlockBackend is always referenced with a child_job, too.

Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Alberto Garcia <[email protected]>

Berto

author
#10 lore raw

PATCH v2 7/19 test-bdrv-drain: Test drain vs. block jobs

In reply to Kevin Wolf

Block jobs must be paused if any of the involved nodes are drained.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
tests/test-bdrv-drain.c +121 -0
index 2aa2b9aa43..019fe9074d 100644
@@ -24,6 +24,7 @@
 
 #include "qemu/osdep.h"
 #include "block/block.h"
+#include "block/blockjob_int.h"
 #include "sysemu/block-backend.h"
 #include "qapi/error.h"
 

@@ -220,6 +221,123 @@ static void test_quiesce_drain(void)
     test_quiesce_common(BDRV_DRAIN, false);
 }
 
+
+typedef struct TestBlockJob {
+    BlockJob common;
+    bool should_complete;
+} TestBlockJob;
+
+static void test_job_completed(BlockJob *job, void *opaque)
+{
+    block_job_completed(job, 0);
+}
+
+static void coroutine_fn test_job_start(void *opaque)
+{
+    TestBlockJob *s = opaque;
+
+    while (!s->should_complete) {
+        block_job_sleep_ns(&s->common, 100000);
+    }
+
+    block_job_defer_to_main_loop(&s->common, test_job_completed, NULL);
+}
+
+static void test_job_complete(BlockJob *job, Error **errp)
+{
+    TestBlockJob *s = container_of(job, TestBlockJob, common);
+    s->should_complete = true;
+}
+
+BlockJobDriver test_job_driver = {
+    .instance_size  = sizeof(TestBlockJob),
+    .start          = test_job_start,
+    .complete       = test_job_complete,
+};
+
+static void test_blockjob_common(enum drain_type drain_type)
+{
+    BlockBackend *blk_src, *blk_target;
+    BlockDriverState *src, *target;
+    BlockJob *job;
+    int ret;
+
+    src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR,
+                               &error_abort);
+    blk_src = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    blk_insert_bs(blk_src, src, &error_abort);
+
+    target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR,
+                                  &error_abort);
+    blk_target = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    blk_insert_bs(blk_target, target, &error_abort);
+
+    job = block_job_create("job0", &test_job_driver, src, 0, BLK_PERM_ALL, 0,
+                           0, NULL, NULL, &error_abort);
+    block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
+    block_job_start(job);
+
+    g_assert_cmpint(job->pause_count, ==, 0);
+    g_assert_false(job->paused);
+    g_assert_false(job->busy); /* We're in block_job_sleep_ns() */
+
+    do_drain_begin(drain_type, src);
+
+    if (drain_type == BDRV_DRAIN_ALL) {
+        /* bdrv_drain_all() drains both src and target, and involves an
+         * additional block_job_pause_all() */
+        g_assert_cmpint(job->pause_count, ==, 3);
+    } else {
+        g_assert_cmpint(job->pause_count, ==, 1);
+    }
+    /* XXX We don't wait until the job is actually paused. Is this okay? */
+    /* g_assert_true(job->paused); */
+    g_assert_false(job->busy); /* The job is paused */
+
+    do_drain_end(drain_type, src);
+
+    g_assert_cmpint(job->pause_count, ==, 0);
+    g_assert_false(job->paused);
+    g_assert_false(job->busy); /* We're in block_job_sleep_ns() */
+
+    do_drain_begin(drain_type, target);
+
+    if (drain_type == BDRV_DRAIN_ALL) {
+        /* bdrv_drain_all() drains both src and target, and involves an
+         * additional block_job_pause_all() */
+        g_assert_cmpint(job->pause_count, ==, 3);
+    } else {
+        g_assert_cmpint(job->pause_count, ==, 1);
+    }
+    /* XXX We don't wait until the job is actually paused. Is this okay? */
+    /* g_assert_true(job->paused); */
+    g_assert_false(job->busy); /* The job is paused */
+
+    do_drain_end(drain_type, target);
+
+    g_assert_cmpint(job->pause_count, ==, 0);
+    g_assert_false(job->paused);
+    g_assert_false(job->busy); /* We're in block_job_sleep_ns() */
+
+    ret = block_job_complete_sync(job, &error_abort);
+    g_assert_cmpint(ret, ==, 0);
+
+    blk_unref(blk_src);
+    blk_unref(blk_target);
+    bdrv_unref(src);
+    bdrv_unref(target);
+}
+
+static void test_blockjob_drain_all(void)
+{
+    test_blockjob_common(BDRV_DRAIN_ALL);
+}
+
+static void test_blockjob_drain(void)
+{
+    test_blockjob_common(BDRV_DRAIN);
+}
+
 int main(int argc, char **argv)
 {
     bdrv_init();

@@ -233,5 +351,8 @@ int main(int argc, char **argv)
     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
 
+    g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
+    g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
+
     return g_test_run();
 }
Signature · 1 line
2.13.6
author
#12 lore raw

PATCH v2 8/19 block: Don't block_job_pause_all() in bdrv_drain_all()

In reply to Kevin Wolf

Block jobs are already paused using the BdrvChildRole drain callbacks, so we don't need an additionall block_job_pause_all() call.

Signed-off-by Kevin Wolf <[email protected]>
---
 block/io.c              |  4 ----
 tests/test-bdrv-drain.c | 10 ++++------
 2 files changed, 4 insertions(+), 10 deletions(-)
block/io.c +0 -4
index 91a52e2d82..74d2e5278e 100644
@@ -338,8 +338,6 @@ void bdrv_drain_all_begin(void)
      * context. */
     assert(qemu_get_current_aio_context() == qemu_get_aio_context());
 
-    block_job_pause_all();
-
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         AioContext *aio_context = bdrv_get_aio_context(bs);
 

@@ -395,8 +393,6 @@ void bdrv_drain_all_end(void)
         aio_enable_external(aio_context);
         aio_context_release(aio_context);
     }
-
-    block_job_resume_all();
 }
 
 void bdrv_drain_all(void)
tests/test-bdrv-drain.c +4 -6
index 019fe9074d..4571137928 100644
@@ -284,9 +284,8 @@ static void test_blockjob_common(enum drain_type drain_type)
     do_drain_begin(drain_type, src);
 
     if (drain_type == BDRV_DRAIN_ALL) {
-        /* bdrv_drain_all() drains both src and target, and involves an
-         * additional block_job_pause_all() */
-        g_assert_cmpint(job->pause_count, ==, 3);
+        /* bdrv_drain_all() drains both src and target */
+        g_assert_cmpint(job->pause_count, ==, 2);
     } else {
         g_assert_cmpint(job->pause_count, ==, 1);
     }

@@ -303,9 +302,8 @@ static void test_blockjob_common(enum drain_type drain_type)
     do_drain_begin(drain_type, target);
 
     if (drain_type == BDRV_DRAIN_ALL) {
-        /* bdrv_drain_all() drains both src and target, and involves an
-         * additional block_job_pause_all() */
-        g_assert_cmpint(job->pause_count, ==, 3);
+        /* bdrv_drain_all() drains both src and target */
+        g_assert_cmpint(job->pause_count, ==, 2);
     } else {
         g_assert_cmpint(job->pause_count, ==, 1);
     }
Signature · 1 line
2.13.6
author
#14 lore raw

PATCH v2 9/19 block: Nested drain_end must still call callbacks

In reply to Kevin Wolf

bdrv_do_drained_begin() restricts the call of parent callbacks and aio_disable_external() to the outermost drain section, but the block driver callbacks are always called. bdrv_do_drained_end() must match this behaviour, otherwise nodes stay drained even if begin/end calls were balanced.

Signed-off-by Kevin Wolf <[email protected]>
---
 block/io.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
block/io.c +7 -5
index 74d2e5278e..6038a16c58 100644
@@ -273,19 +273,21 @@ void bdrv_drained_begin(BlockDriverState *bs)
 
 void bdrv_drained_end(BlockDriverState *bs)
 {
+    int old_quiesce_counter;
+
     if (qemu_in_coroutine()) {
         bdrv_co_yield_to_drain(bs, false);
         return;
     }
     assert(bs->quiesce_counter > 0);
-    if (atomic_fetch_dec(&bs->quiesce_counter) > 1) {
-        return;
-    }
+    old_quiesce_counter = atomic_fetch_dec(&bs->quiesce_counter);
 
     /* Re-enable things in child-to-parent order */
     bdrv_drain_invoke(bs, false, false);
-    bdrv_parent_drained_end(bs);
-    aio_enable_external(bdrv_get_aio_context(bs));
+    if (old_quiesce_counter == 1) {
+        bdrv_parent_drained_end(bs);
+        aio_enable_external(bdrv_get_aio_context(bs));
+    }
 }
 
 /*
Signature · 1 line
2.13.6
#15 lore raw

Re: [Qemu-devel] [Qemu-block] [PATCH v2 09/19] block: Nested drain_end must still call callbacks

Quoted 5 lines · Kevin Wolf

bdrv_do_drained_begin() restricts the call of parent callbacks and aio_disable_external() to the outermost drain section, but the block driver callbacks are always called. bdrv_do_drained_end() must match this behaviour, otherwise nodes stay drained even if begin/end calls were balanced.

Is this patch in the correct place in the series? I was confused becaue you mention bdrv_do_drained_begin() and bdrv_do_drained_end() that don't seem to exist yet, I see you add them in a later patch.

Berto

author
#16 lore raw

Re: [Qemu-devel] [Qemu-block] [PATCH v2 09/19] block: Nested drain_end must still call callbacks

Am 08.01.2018 um 16:41 hat Alberto Garcia geschrieben:

Quoted 10 lines · Kevin Wolf
Quoted 5 lines

bdrv_do_drained_begin() restricts the call of parent callbacks and aio_disable_external() to the outermost drain section, but the block driver callbacks are always called. bdrv_do_drained_end() must match this behaviour, otherwise nodes stay drained even if begin/end calls were balanced.

Is this patch in the correct place in the series? I was confused becaue you mention bdrv_do_drained_begin() and bdrv_do_drained_end() that don't seem to exist yet, I see you add them in a later patch.

I think I only forgot to update the commit message when I had to move some patches around so I could attack one bug after another and keep the series reviewable.

The series has landed in master today, so for this kind of thing it's too late anyway, but additional review never hurts. If you find something, we'll have to do a follow-up patch.

Kevin

author
#17 lore raw

PATCH v2 10/19 test-bdrv-drain: Test nested drain sections

In reply to Kevin Wolf
Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
tests/test-bdrv-drain.c +57 -0
index 4571137928..ede5cf6e64 100644
@@ -85,6 +85,7 @@ static void aio_ret_cb(void *opaque, int ret)
 enum drain_type {
     BDRV_DRAIN_ALL,
     BDRV_DRAIN,
+    DRAIN_TYPE_MAX,
 };
 
 static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)

@@ -221,6 +222,60 @@ static void test_quiesce_drain(void)
     test_quiesce_common(BDRV_DRAIN, false);
 }
 
+static void test_nested(void)
+{
+    BlockBackend *blk;
+    BlockDriverState *bs, *backing;
+    BDRVTestState *s, *backing_s;
+    enum drain_type outer, inner;
+
+    blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
+                              &error_abort);
+    s = bs->opaque;
+    blk_insert_bs(blk, bs, &error_abort);
+
+    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
+    backing_s = backing->opaque;
+    bdrv_set_backing_hd(bs, backing, &error_abort);
+
+    for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
+        for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
+            /* XXX bdrv_drain_all() doesn't increase the quiesce_counter */
+            int bs_quiesce      = (outer != BDRV_DRAIN_ALL) +
+                                  (inner != BDRV_DRAIN_ALL);
+            int backing_quiesce = 0;
+            int backing_cb_cnt  = (outer != BDRV_DRAIN) +
+                                  (inner != BDRV_DRAIN);
+
+            g_assert_cmpint(bs->quiesce_counter, ==, 0);
+            g_assert_cmpint(backing->quiesce_counter, ==, 0);
+            g_assert_cmpint(s->drain_count, ==, 0);
+            g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+            do_drain_begin(outer, bs);
+            do_drain_begin(inner, bs);
+
+            g_assert_cmpint(bs->quiesce_counter, ==, bs_quiesce);
+            g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
+            g_assert_cmpint(s->drain_count, ==, 2);
+            g_assert_cmpint(backing_s->drain_count, ==, backing_cb_cnt);
+
+            do_drain_end(inner, bs);
+            do_drain_end(outer, bs);
+
+            g_assert_cmpint(bs->quiesce_counter, ==, 0);
+            g_assert_cmpint(backing->quiesce_counter, ==, 0);
+            g_assert_cmpint(s->drain_count, ==, 0);
+            g_assert_cmpint(backing_s->drain_count, ==, 0);
+        }
+    }
+
+    bdrv_unref(backing);
+    bdrv_unref(bs);
+    blk_unref(blk);
+}
+
 
 typedef struct TestBlockJob {
     BlockJob common;

@@ -349,6 +404,8 @@ int main(int argc, char **argv)
     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
 
+    g_test_add_func("/bdrv-drain/nested", test_nested);
+
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
Signature · 1 line
2.13.6
author
#18 lore raw

PATCH v2 11/19 block: Don't notify parents in drain call chain

In reply to Kevin Wolf

This is in preparation for subtree drains, i.e. drained sections that affect not only a single node, but recursively all child nodes, too.

Calling the parent callbacks for drain is pointless when we just came from that parent node recursively and leads to multiple increases of bs->quiesce_counter in a single drain call. Don't do it.

In order for this to work correctly, the parent callback must be called for every bdrv_drain_begin/end() call, not only for the outermost one:

If we have a node N with two parents A and B, recursive draining of A should cause the quiesce_counter of B to increased because its child N is drained independently of B. If now B is recursively drained, too, A must increase its quiesce_counter because N is drained independently of A only now, even if N is going from quiesce_counter 1 to 2.

Signed-off-by Kevin Wolf <[email protected]>
---
 include/block/block.h |  4 ++--
 block.c               | 13 +++++++++----
 block/io.c            | 47 ++++++++++++++++++++++++++++++++++-------------
 3 files changed, 45 insertions(+), 19 deletions(-)
include/block/block.h +2 -2
index c05cac57e5..60c5d11029 100644
@@ -585,7 +585,7 @@ void bdrv_io_unplug(BlockDriverState *bs);
  * Begin a quiesced section of all users of @bs. This is part of
  * bdrv_drained_begin.
  */
-void bdrv_parent_drained_begin(BlockDriverState *bs);
+void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
 
 /**
  * bdrv_parent_drained_end:

@@ -593,7 +593,7 @@ void bdrv_parent_drained_begin(BlockDriverState *bs);
  * End a quiesced section of all users of @bs. This is part of
  * bdrv_drained_end.
  */
-void bdrv_parent_drained_end(BlockDriverState *bs);
+void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
 
 /**
  * bdrv_drained_begin:
block.c +9 -4
index ddb6836c52..5867a2a2a0 100644
@@ -1972,13 +1972,16 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
                                       BlockDriverState *new_bs)
 {
     BlockDriverState *old_bs = child->bs;
+    int i;
 
     if (old_bs && new_bs) {
         assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
     }
     if (old_bs) {
         if (old_bs->quiesce_counter && child->role->drained_end) {
-            child->role->drained_end(child);
+            for (i = 0; i < old_bs->quiesce_counter; i++) {
+                child->role->drained_end(child);
+            }
         }
         if (child->role->detach) {
             child->role->detach(child);

@@ -1991,7 +1994,9 @@ 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) {
-            child->role->drained_begin(child);
+            for (i = 0; i < new_bs->quiesce_counter; i++) {
+                child->role->drained_begin(child);
+            }
         }
 
         if (child->role->attach) {

@@ -4750,7 +4755,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
     AioContext *ctx = bdrv_get_aio_context(bs);
 
     aio_disable_external(ctx);
-    bdrv_parent_drained_begin(bs);
+    bdrv_parent_drained_begin(bs, NULL);
     bdrv_drain(bs); /* ensure there are no in-flight requests */
 
     while (aio_poll(ctx, false)) {

@@ -4764,7 +4769,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
      */
     aio_context_acquire(new_context);
     bdrv_attach_aio_context(bs, new_context);
-    bdrv_parent_drained_end(bs);
+    bdrv_parent_drained_end(bs, NULL);
     aio_enable_external(ctx);
     aio_context_release(new_context);
 }
block/io.c +34 -13

145 lines not on this page · raw message

Signature · 1 line
2.13.6
author
#19 lore raw

PATCH v2 12/19 block: Add bdrv_subtree_drained_begin/end()

In reply to Kevin Wolf

bdrv_drained_begin() waits for the completion of requests in the whole subtree, but it only actually keeps its immediate bs parameter quiesced until bdrv_drained_end().

Add a version that keeps the whole subtree drained. As of this commit, graph changes cannot be allowed during a subtree drained section, but this will be fixed soon.

Signed-off-by Kevin Wolf <[email protected]>
---
 include/block/block.h | 13 +++++++++++++
 block/io.c            | 54 ++++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 56 insertions(+), 11 deletions(-)
include/block/block.h +13 -0
index 60c5d11029..de9c5a2b9b 100644
@@ -608,12 +608,25 @@ void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
 void bdrv_drained_begin(BlockDriverState *bs);
 
 /**
+ * Like bdrv_drained_begin, but recursively begins a quiesced section for
+ * exclusive access to all child nodes as well.
+ *
+ * Graph changes are not allowed during a subtree drain section.
+ */
+void bdrv_subtree_drained_begin(BlockDriverState *bs);
+
+/**
  * bdrv_drained_end:
  *
  * End a quiescent section started by bdrv_drained_begin().
  */
 void bdrv_drained_end(BlockDriverState *bs);
 
+/**
+ * End a quiescent section started by bdrv_subtree_drained_begin().
+ */
+void bdrv_subtree_drained_end(BlockDriverState *bs);
+
 void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
                     Error **errp);
 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
block/io.c +43 -11

119 lines not on this page · raw message

Signature · 1 line
2.13.6
author
#20 lore raw

PATCH v2 13/19 test-bdrv-drain: Tests for bdrv_subtree_drain

In reply to Kevin Wolf

Add a subtree drain version to the existing test cases.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)
tests/test-bdrv-drain.c +26 -1
index ede5cf6e64..c00d96bb2f 100644
@@ -85,6 +85,7 @@ static void aio_ret_cb(void *opaque, int ret)
 enum drain_type {
     BDRV_DRAIN_ALL,
     BDRV_DRAIN,
+    BDRV_SUBTREE_DRAIN,
     DRAIN_TYPE_MAX,
 };
 

@@ -93,6 +94,7 @@ static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)
     switch (drain_type) {
     case BDRV_DRAIN_ALL:        bdrv_drain_all_begin(); break;
     case BDRV_DRAIN:            bdrv_drained_begin(bs); break;
+    case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_begin(bs); break;
     default:                    g_assert_not_reached();
     }
 }

@@ -102,6 +104,7 @@ static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs)
     switch (drain_type) {
     case BDRV_DRAIN_ALL:        bdrv_drain_all_end(); break;
     case BDRV_DRAIN:            bdrv_drained_end(bs); break;
+    case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_end(bs); break;
     default:                    g_assert_not_reached();
     }
 }

@@ -180,6 +183,11 @@ static void test_drv_cb_drain(void)
     test_drv_cb_common(BDRV_DRAIN, false);
 }
 
+static void test_drv_cb_drain_subtree(void)
+{
+    test_drv_cb_common(BDRV_SUBTREE_DRAIN, true);
+}
+
 static void test_quiesce_common(enum drain_type drain_type, bool recursive)
 {
     BlockBackend *blk;

@@ -222,6 +230,11 @@ static void test_quiesce_drain(void)
     test_quiesce_common(BDRV_DRAIN, false);
 }
 
+static void test_quiesce_drain_subtree(void)
+{
+    test_quiesce_common(BDRV_SUBTREE_DRAIN, true);
+}
+
 static void test_nested(void)
 {
     BlockBackend *blk;

@@ -244,7 +257,8 @@ static void test_nested(void)
             /* XXX bdrv_drain_all() doesn't increase the quiesce_counter */
             int bs_quiesce      = (outer != BDRV_DRAIN_ALL) +
                                   (inner != BDRV_DRAIN_ALL);
-            int backing_quiesce = 0;
+            int backing_quiesce = (outer == BDRV_SUBTREE_DRAIN) +
+                                  (inner == BDRV_SUBTREE_DRAIN);
             int backing_cb_cnt  = (outer != BDRV_DRAIN) +
                                   (inner != BDRV_DRAIN);
 

@@ -391,6 +405,11 @@ static void test_blockjob_drain(void)
     test_blockjob_common(BDRV_DRAIN);
 }
 
+static void test_blockjob_drain_subtree(void)
+{
+    test_blockjob_common(BDRV_SUBTREE_DRAIN);
+}
+
 int main(int argc, char **argv)
 {
     bdrv_init();

@@ -400,14 +419,20 @@ int main(int argc, char **argv)
 
     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
     g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
+    g_test_add_func("/bdrv-drain/driver-cb/drain_subtree",
+                    test_drv_cb_drain_subtree);
 
     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
+    g_test_add_func("/bdrv-drain/quiesce/drain_subtree",
+                    test_quiesce_drain_subtree);
 
     g_test_add_func("/bdrv-drain/nested", test_nested);
 
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
+    g_test_add_func("/bdrv-drain/blockjob/drain_subtree",
+                    test_blockjob_drain_subtree);
 
     return g_test_run();
 }
Signature · 1 line
2.13.6
author
#21 lore raw

PATCH v2 14/19 test-bdrv-drain: Test behaviour in coroutine context

In reply to Kevin Wolf

If bdrv_do_drained_begin/end() are called in coroutine context, they first use a BH to get out of the coroutine context. Call some existing tests again from a coroutine to cover this code path.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
tests/test-bdrv-drain.c +59 -0
index c00d96bb2f..16ff3483e3 100644
@@ -82,6 +82,34 @@ static void aio_ret_cb(void *opaque, int ret)
     *aio_ret = ret;
 }
 
+typedef struct CallInCoroutineData {
+    void (*entry)(void);
+    bool done;
+} CallInCoroutineData;
+
+static coroutine_fn void call_in_coroutine_entry(void *opaque)
+{
+    CallInCoroutineData *data = opaque;
+
+    data->entry();
+    data->done = true;
+}
+
+static void call_in_coroutine(void (*entry)(void))
+{
+    Coroutine *co;
+    CallInCoroutineData data = {
+        .entry  = entry,
+        .done   = false,
+    };
+
+    co = qemu_coroutine_create(call_in_coroutine_entry, &data);
+    qemu_coroutine_enter(co);
+    while (!data.done) {
+        aio_poll(qemu_get_aio_context(), true);
+    }
+}
+
 enum drain_type {
     BDRV_DRAIN_ALL,
     BDRV_DRAIN,

@@ -188,6 +216,16 @@ static void test_drv_cb_drain_subtree(void)
     test_drv_cb_common(BDRV_SUBTREE_DRAIN, true);
 }
 
+static void test_drv_cb_co_drain(void)
+{
+    call_in_coroutine(test_drv_cb_drain);
+}
+
+static void test_drv_cb_co_drain_subtree(void)
+{
+    call_in_coroutine(test_drv_cb_drain_subtree);
+}
+
 static void test_quiesce_common(enum drain_type drain_type, bool recursive)
 {
     BlockBackend *blk;

@@ -235,6 +273,16 @@ static void test_quiesce_drain_subtree(void)
     test_quiesce_common(BDRV_SUBTREE_DRAIN, true);
 }
 
+static void test_quiesce_co_drain(void)
+{
+    call_in_coroutine(test_quiesce_drain);
+}
+
+static void test_quiesce_co_drain_subtree(void)
+{
+    call_in_coroutine(test_quiesce_drain_subtree);
+}
+
 static void test_nested(void)
 {
     BlockBackend *blk;

@@ -422,11 +470,22 @@ int main(int argc, char **argv)
     g_test_add_func("/bdrv-drain/driver-cb/drain_subtree",
                     test_drv_cb_drain_subtree);
 
+    // XXX bdrv_drain_all() doesn't work in coroutine context
+    g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain);
+    g_test_add_func("/bdrv-drain/driver-cb/co/drain_subtree",
+                    test_drv_cb_co_drain_subtree);
+
+
     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
     g_test_add_func("/bdrv-drain/quiesce/drain_subtree",
                     test_quiesce_drain_subtree);
 
+    // XXX bdrv_drain_all() doesn't work in coroutine context
+    g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain);
+    g_test_add_func("/bdrv-drain/quiesce/co/drain_subtree",
+                    test_quiesce_co_drain_subtree);
+
     g_test_add_func("/bdrv-drain/nested", test_nested);
 
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
Signature · 1 line
2.13.6
author
#22 lore raw

PATCH v2 15/19 test-bdrv-drain: Recursive draining with multiple parents

In reply to Kevin Wolf

Test that drain sections are correctly propagated through the graph.

Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
tests/test-bdrv-drain.c +74 -0
index 16ff3483e3..9e66b40465 100644
@@ -338,6 +338,79 @@ static void test_nested(void)
     blk_unref(blk);
 }
 
+static void test_multiparent(void)
+{
+    BlockBackend *blk_a, *blk_b;
+    BlockDriverState *bs_a, *bs_b, *backing;
+    BDRVTestState *a_s, *b_s, *backing_s;
+
+    blk_a = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
+                                &error_abort);
+    a_s = bs_a->opaque;
+    blk_insert_bs(blk_a, bs_a, &error_abort);
+
+    blk_b = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
+                                &error_abort);
+    b_s = bs_b->opaque;
+    blk_insert_bs(blk_b, bs_b, &error_abort);
+
+    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
+    backing_s = backing->opaque;
+    bdrv_set_backing_hd(bs_a, backing, &error_abort);
+    bdrv_set_backing_hd(bs_b, backing, &error_abort);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+    g_assert_cmpint(a_s->drain_count, ==, 0);
+    g_assert_cmpint(b_s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
+    g_assert_cmpint(backing->quiesce_counter, ==, 1);
+    g_assert_cmpint(a_s->drain_count, ==, 1);
+    g_assert_cmpint(b_s->drain_count, ==, 1);
+    g_assert_cmpint(backing_s->drain_count, ==, 1);
+
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 2);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
+    g_assert_cmpint(backing->quiesce_counter, ==, 2);
+    g_assert_cmpint(a_s->drain_count, ==, 2);
+    g_assert_cmpint(b_s->drain_count, ==, 2);
+    g_assert_cmpint(backing_s->drain_count, ==, 2);
+
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
+    g_assert_cmpint(backing->quiesce_counter, ==, 1);
+    g_assert_cmpint(a_s->drain_count, ==, 1);
+    g_assert_cmpint(b_s->drain_count, ==, 1);
+    g_assert_cmpint(backing_s->drain_count, ==, 1);
+
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+    g_assert_cmpint(a_s->drain_count, ==, 0);
+    g_assert_cmpint(b_s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    bdrv_unref(backing);
+    bdrv_unref(bs_a);
+    bdrv_unref(bs_b);
+    blk_unref(blk_a);
+    blk_unref(blk_b);
+}
+
 
 typedef struct TestBlockJob {
     BlockJob common;

@@ -487,6 +560,7 @@ int main(int argc, char **argv)
                     test_quiesce_co_drain_subtree);
 
     g_test_add_func("/bdrv-drain/nested", test_nested);
+    g_test_add_func("/bdrv-drain/multiparent", test_multiparent);
 
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
Signature · 1 line
2.13.6
author
#23 lore raw

PATCH v2 16/19 block: Allow graph changes in subtree drained section

In reply to Kevin Wolf

We need to remember how many of the drain sections in which a node is were recursive (i.e. subtree drain rather than node drain), so that they can be correctly applied when children are added or removed during the drained section.

With this change, it is safe to modify the graph even inside a bdrv_subtree_drained_begin/end() section.

Signed-off-by Kevin Wolf <[email protected]>
---
 include/block/block.h     |  2 --
 include/block/block_int.h |  5 +++++
 block.c                   | 32 +++++++++++++++++++++++++++++---
 block/io.c                | 28 ++++++++++++++++++++++++----
 4 files changed, 58 insertions(+), 9 deletions(-)
include/block/block.h +0 -2
index de9c5a2b9b..9b12774ddf 100644
@@ -610,8 +610,6 @@ void bdrv_drained_begin(BlockDriverState *bs);
 /**
  * Like bdrv_drained_begin, but recursively begins a quiesced section for
  * exclusive access to all child nodes as well.
- *
- * Graph changes are not allowed during a subtree drain section.
  */
 void bdrv_subtree_drained_begin(BlockDriverState *bs);
include/block/block_int.h +5 -0
index e107163594..29cafa4236 100644
@@ -717,6 +717,8 @@ struct BlockDriverState {
 
     /* Accessed with atomic ops.  */
     int quiesce_counter;
+    int recursive_quiesce_counter;
+
     unsigned int write_gen;               /* Current data generation */
 
     /* Protected by reqs_lock.  */

@@ -768,6 +770,9 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
     int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
     BdrvRequestFlags flags);
 
+void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent);
+void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent);
+
 int get_tmp_filename(char *filename, int size);
 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
                             const char *filename);
block.c +29 -3
index 5867a2a2a0..56e446cf9d 100644
@@ -822,6 +822,18 @@ static void bdrv_child_cb_drained_end(BdrvChild *child)
     bdrv_drained_end(bs);
 }
 
+static void bdrv_child_cb_attach(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+    bdrv_apply_subtree_drain(child, bs);
+}
+
+static void bdrv_child_cb_detach(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+    bdrv_unapply_subtree_drain(child, bs);
+}
+
 static int bdrv_child_cb_inactivate(BdrvChild *child)
 {
     BlockDriverState *bs = child->opaque;

@@ -889,6 +901,8 @@ const BdrvChildRole child_file = {
     .inherit_options = bdrv_inherited_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .attach          = bdrv_child_cb_attach,
+    .detach          = bdrv_child_cb_detach,
     .inactivate      = bdrv_child_cb_inactivate,
 };
 

@@ -911,6 +925,8 @@ const BdrvChildRole child_format = {
     .inherit_options = bdrv_inherited_fmt_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_end     = bdrv_child_cb_drained_end,
+    .attach          = bdrv_child_cb_attach,
+    .detach          = bdrv_child_cb_detach,
     .inactivate      = bdrv_child_cb_inactivate,
 };
 

@@ -953,6 +969,8 @@ static void bdrv_backing_attach(BdrvChild *c)
                     parent->backing_blocker);
     bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
                     parent->backing_blocker);
+
+    bdrv_child_cb_attach(c);
 }
 
 static void bdrv_backing_detach(BdrvChild *c)

@@ -963,6 +981,8 @@ static void bdrv_backing_detach(BdrvChild *c)
     bdrv_op_unblock_all(c->bs, parent->backing_blocker);
     error_free(parent->backing_blocker);
     parent->backing_blocker = NULL;
+
+    bdrv_child_cb_detach(c);
 }
 
 /*

@@ -1978,14 +1998,17 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
         assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
     }
     if (old_bs) {
+        /* Detach first so that the recursive drain sections coming from @child
+         * are already gone and we only end the drain sections that came from
+         * elsewhere. */
+        if (child->role->detach) {
+            child->role->detach(child);
+        }
         if (old_bs->quiesce_counter && child->role->drained_end) {
             for (i = 0; i < old_bs->quiesce_counter; i++) {
                 child->role->drained_end(child);
             }
         }
-        if (child->role->detach) {
-            child->role->detach(child);
-        }
         QLIST_REMOVE(child, next_parent);
     }
 

@@ -1999,6 +2022,9 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
             }
         }
 
+        /* Attach only after starting new drained sections, so that recursive
+         * drain sections coming from @child don't get an extra .drained_begin
+         * callback. */
         if (child->role->attach) {
             child->role->attach(child);
         }
block/io.c +24 -4
index 6befef166d..7ea402352e 100644
@@ -270,8 +270,8 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
     assert(data.done);
 }
 
-static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
-                                  BdrvChild *parent)
+void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
+                           BdrvChild *parent)
 {
     BdrvChild *child, *next;
 

@@ -290,6 +290,7 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
     bdrv_drain_recurse(bs);
 
     if (recursive) {
+        bs->recursive_quiesce_counter++;
         QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
             bdrv_do_drained_begin(child->bs, true, child);
         }

@@ -306,8 +307,8 @@ void bdrv_subtree_drained_begin(BlockDriverState *bs)
     bdrv_do_drained_begin(bs, true, NULL);
 }
 
-static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
-                                BdrvChild *parent)
+void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
+                         BdrvChild *parent)
 {
     BdrvChild *child, *next;
     int old_quiesce_counter;

@@ -327,6 +328,7 @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
     }
 
     if (recursive) {
+        bs->recursive_quiesce_counter--;
         QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
             bdrv_do_drained_end(child->bs, true, child);
         }

@@ -343,6 +345,24 @@ void bdrv_subtree_drained_end(BlockDriverState *bs)
     bdrv_do_drained_end(bs, true, NULL);
 }
 
+void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent)
+{
+    int i;
+
+    for (i = 0; i < new_parent->recursive_quiesce_counter; i++) {
+        bdrv_do_drained_begin(child->bs, true, child);
+    }
+}
+
+void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent)
+{
+    int i;
+
+    for (i = 0; i < old_parent->recursive_quiesce_counter; i++) {
+        bdrv_do_drained_end(child->bs, true, child);
+    }
+}
+
 /*
  * Wait for pending requests to complete on a single BlockDriverState subtree,
  * and suspend block driver's internal I/O until next request arrives.
Signature · 1 line
2.13.6
author
#24 lore raw

PATCH v2 17/19 test-bdrv-drain: Test graph changes in drained section

In reply to Kevin Wolf
Signed-off-by Kevin Wolf <[email protected]>
---
 tests/test-bdrv-drain.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
tests/test-bdrv-drain.c +80 -0
index 9e66b40465..7e8bd591a4 100644
@@ -411,6 +411,85 @@ static void test_multiparent(void)
     blk_unref(blk_b);
 }
 
+static void test_graph_change(void)
+{
+    BlockBackend *blk_a, *blk_b;
+    BlockDriverState *bs_a, *bs_b, *backing;
+    BDRVTestState *a_s, *b_s, *backing_s;
+
+    blk_a = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
+                                &error_abort);
+    a_s = bs_a->opaque;
+    blk_insert_bs(blk_a, bs_a, &error_abort);
+
+    blk_b = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
+    bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
+                                &error_abort);
+    b_s = bs_b->opaque;
+    blk_insert_bs(blk_b, bs_b, &error_abort);
+
+    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
+    backing_s = backing->opaque;
+    bdrv_set_backing_hd(bs_a, backing, &error_abort);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+    g_assert_cmpint(a_s->drain_count, ==, 0);
+    g_assert_cmpint(b_s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
+    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
+
+    bdrv_set_backing_hd(bs_b, backing, &error_abort);
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
+    g_assert_cmpint(backing->quiesce_counter, ==, 5);
+    g_assert_cmpint(a_s->drain_count, ==, 5);
+    g_assert_cmpint(b_s->drain_count, ==, 5);
+    g_assert_cmpint(backing_s->drain_count, ==, 5);
+
+    bdrv_set_backing_hd(bs_b, NULL, &error_abort);
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 3);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
+    g_assert_cmpint(backing->quiesce_counter, ==, 3);
+    g_assert_cmpint(a_s->drain_count, ==, 3);
+    g_assert_cmpint(b_s->drain_count, ==, 2);
+    g_assert_cmpint(backing_s->drain_count, ==, 3);
+
+    bdrv_set_backing_hd(bs_b, backing, &error_abort);
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
+    g_assert_cmpint(backing->quiesce_counter, ==, 5);
+    g_assert_cmpint(a_s->drain_count, ==, 5);
+    g_assert_cmpint(b_s->drain_count, ==, 5);
+    g_assert_cmpint(backing_s->drain_count, ==, 5);
+
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
+    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
+
+    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
+    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
+    g_assert_cmpint(backing->quiesce_counter, ==, 0);
+    g_assert_cmpint(a_s->drain_count, ==, 0);
+    g_assert_cmpint(b_s->drain_count, ==, 0);
+    g_assert_cmpint(backing_s->drain_count, ==, 0);
+
+    bdrv_unref(backing);
+    bdrv_unref(bs_a);
+    bdrv_unref(bs_b);
+    blk_unref(blk_a);
+    blk_unref(blk_b);
+}
+
 
 typedef struct TestBlockJob {
     BlockJob common;

@@ -561,6 +640,7 @@ int main(int argc, char **argv)
 
     g_test_add_func("/bdrv-drain/nested", test_nested);
     g_test_add_func("/bdrv-drain/multiparent", test_multiparent);
+    g_test_add_func("/bdrv-drain/graph-change", test_graph_change);
 
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
Signature · 1 line
2.13.6
author
#25 lore raw

PATCH v2 18/19 commit: Simplify reopen of base

In reply to Kevin Wolf

Since commit bde70715, base is the only node that is reopened in commit_start(). This means that the code, which still involves an explicit BlockReopenQueue, can now be simplified by using bdrv_reopen().

Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Fam Zheng <[email protected]>
---
 block/commit.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)
block/commit.c +1 -7
index c5327551ce..bb6c904704 100644
@@ -277,7 +277,6 @@ void commit_start(const char *job_id, BlockDriverState *bs,
                   const char *filter_node_name, Error **errp)
 {
     CommitBlockJob *s;
-    BlockReopenQueue *reopen_queue = NULL;
     int orig_base_flags;
     BlockDriverState *iter;
     BlockDriverState *commit_top_bs = NULL;

@@ -299,12 +298,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     /* convert base to r/w, if necessary */
     orig_base_flags = bdrv_get_flags(base);
     if (!(orig_base_flags & BDRV_O_RDWR)) {
-        reopen_queue = bdrv_reopen_queue(reopen_queue, base, NULL,
-                                         orig_base_flags | BDRV_O_RDWR);
-    }
-
-    if (reopen_queue) {
-        bdrv_reopen_multiple(bdrv_get_aio_context(bs), reopen_queue, &local_err);
+        bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err);
         if (local_err != NULL) {
             error_propagate(errp, local_err);
             goto fail;
Signature · 1 line
2.13.6
author
#26 lore raw

PATCH v2 19/19 block: Keep nodes drained between reopen_queue/multiple

In reply to Kevin Wolf

The bdrv_reopen*() implementation doesn't like it if the graph is changed between queuing nodes for reopen and actually reopening them (one of the reasons is that queuing can be recursive).

So instead of draining the device only in bdrv_reopen_multiple(), require that callers already drained all affected nodes, and assert this in bdrv_reopen_queue().

Signed-off-by Kevin Wolf <[email protected]>
Reviewed-by Fam Zheng <[email protected]>
---
 block.c             | 23 ++++++++++++++++-------
 block/replication.c |  6 ++++++
 qemu-io-cmds.c      |  3 +++
 3 files changed, 25 insertions(+), 7 deletions(-)
block.c +16 -7
index 56e446cf9d..6b4401760f 100644
@@ -2766,6 +2766,7 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
  * returns a pointer to bs_queue, which is either the newly allocated
  * bs_queue, or the existing bs_queue being used.
  *
+ * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple().
  */
 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
                                                  BlockDriverState *bs,

@@ -2781,6 +2782,11 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     BdrvChild *child;
     QDict *old_options, *explicit_options;
 
+    /* Make sure that the caller remembered to use a drained section. This is
+     * important to avoid graph changes between the recursive queuing here and
+     * bdrv_reopen_multiple(). */
+    assert(bs->quiesce_counter > 0);
+
     if (bs_queue == NULL) {
         bs_queue = g_new0(BlockReopenQueue, 1);
         QSIMPLEQ_INIT(bs_queue);

@@ -2905,6 +2911,8 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
  * If all devices prepare successfully, then the changes are committed
  * to all devices.
  *
+ * All affected nodes must be drained between bdrv_reopen_queue() and
+ * bdrv_reopen_multiple().
  */
 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp)
 {

@@ -2914,11 +2922,8 @@ int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **er
 
     assert(bs_queue != NULL);
 
-    aio_context_release(ctx);
-    bdrv_drain_all_begin();
-    aio_context_acquire(ctx);
-
     QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
+        assert(bs_entry->state.bs->quiesce_counter > 0);
         if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
             error_propagate(errp, local_err);
             goto cleanup;

@@ -2947,8 +2952,6 @@ cleanup:
     }
     g_free(bs_queue);
 
-    bdrv_drain_all_end();
-
     return ret;
 }
 

@@ -2958,12 +2961,18 @@ int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
 {
     int ret = -1;
     Error *local_err = NULL;
-    BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
+    BlockReopenQueue *queue;
 
+    bdrv_subtree_drained_begin(bs);
+
+    queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
     ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
     }
+
+    bdrv_subtree_drained_end(bs);
+
     return ret;
 }
block/replication.c +6 -0
index e41e293d2b..b1ea3caa4b 100644
@@ -394,6 +394,9 @@ static void reopen_backing_file(BlockDriverState *bs, bool writable,
         new_secondary_flags = s->orig_secondary_flags;
     }
 
+    bdrv_subtree_drained_begin(s->hidden_disk->bs);
+    bdrv_subtree_drained_begin(s->secondary_disk->bs);
+
     if (orig_hidden_flags != new_hidden_flags) {
         reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs, NULL,
                                          new_hidden_flags);

@@ -409,6 +412,9 @@ static void reopen_backing_file(BlockDriverState *bs, bool writable,
                              reopen_queue, &local_err);
         error_propagate(errp, local_err);
     }
+
+    bdrv_subtree_drained_end(s->hidden_disk->bs);
+    bdrv_subtree_drained_end(s->secondary_disk->bs);
 }
 
 static void backup_job_cleanup(BlockDriverState *bs)
qemu-io-cmds.c +3 -0
index de8e3de726..a6a70fc3dc 100644
@@ -2013,8 +2013,11 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv)
     opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;
     qemu_opts_reset(&reopen_opts);
 
+    bdrv_subtree_drained_begin(bs);
     brq = bdrv_reopen_queue(NULL, bs, opts, flags);
     bdrv_reopen_multiple(bdrv_get_aio_context(bs), brq, &local_err);
+    bdrv_subtree_drained_end(bs);
+
     if (local_err) {
         error_report_err(local_err);
     } else {
Signature · 1 line
2.13.6