[PULL 00/11] Block layer patches

[PULL 00/11] Block layer patches

[Kevin Wolf]

The following changes since commit 0280396a33c7210c4df5306afeab63411a41535a:

  Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-gdbstub-150221-1' into staging (2021-02-15 10:13:13 +0000)

are available in the Git repository at:

  git://repo.or.cz/qemu/kevin.git tags/for-upstream

for you to fetch changes up to b248e61652e20c3353af4b0ccb90f17d76f4db21:

  monitor/qmp: Stop processing requests when shutdown is requested (2021-02-15 15:10:14 +0100)

----------------------------------------------------------------
Block layer patches:

- qemu-storage-daemon: Enable object-add
- blockjob: Fix crash with IOthread when block commit after snapshot
- monitor: Shutdown fixes
- xen-block: fix reporting of discard feature
- qcow2: Remove half-initialised image file after failed image creation
- ahci: Fix DMA direction
- iotests fixes

----------------------------------------------------------------
Alexander Bulekov (1):
      hw/ide/ahci: map cmd_fis as DMA_DIRECTION_TO_DEVICE

Kevin Wolf (3):
      qemu-storage-daemon: Enable object-add
      monitor: Fix assertion failure on shutdown
      monitor/qmp: Stop processing requests when shutdown is requested

Max Reitz (1):
      iotests: Consistent $IMGOPTS boundary matching

Maxim Levitsky (3):
      crypto: luks: Fix tiny memory leak
      block: add bdrv_co_delete_file_noerr
      block: qcow2: remove the created file on initialization error

Michael Qiu (1):
      blockjob: Fix crash with IOthread when block commit after snapshot

Roger Pau Monné (1):
      xen-block: fix reporting of discard feature

Thomas Huth (1):
      tests/qemu-iotests: Remove test 259 from the "auto" group

 include/block/block.h                |  1 +
 block.c                              | 22 ++++++++++++++++++++++
 block/crypto.c                       | 13 ++-----------
 block/qcow2.c                        |  8 +++++---
 blockjob.c                           |  8 ++++++--
 hw/block/xen-block.c                 |  1 +
 hw/ide/ahci.c                        | 12 ++++++------
 monitor/monitor.c                    | 25 +++++++++++++++----------
 monitor/qmp.c                        |  5 +++++
 storage-daemon/qemu-storage-daemon.c |  2 ++
 tests/qemu-iotests/259               |  2 +-
 tests/qemu-iotests/common.rc         |  4 +++-
 12 files changed, 69 insertions(+), 34 deletions(-)

[PULL 01/11] qemu-storage-daemon: Enable object-add

[Kevin Wolf]

As we don't have a fully QAPIfied version of object-add yet and it still
has 'gen': false in the schema, it needs to be registered explicitly in
init_qmp_commands() to be available for users.

Fixes: 2af282ec51a27116d0402cab237b8970800f870c
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210204072137.19663-1-kwolf@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 storage-daemon/qemu-storage-daemon.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/storage-daemon/qemu-storage-daemon.c b/storage-daemon/qemu-storage-daemon.c
index d8d172cc60..9021a46b3a 100644
--- a/storage-daemon/qemu-storage-daemon.c
+++ b/storage-daemon/qemu-storage-daemon.c
@@ -144,6 +144,8 @@ static void init_qmp_commands(void)
     qmp_init_marshal(&qmp_commands);
     qmp_register_command(&qmp_commands, "query-qmp-schema",
                          qmp_query_qmp_schema, QCO_ALLOW_PRECONFIG);
+    qmp_register_command(&qmp_commands, "object-add", qmp_object_add,
+                         QCO_NO_OPTIONS);
 
     QTAILQ_INIT(&qmp_cap_negotiation_commands);
     qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
-- 
2.29.2

[PULL 02/11] iotests: Consistent $IMGOPTS boundary matching

[Kevin Wolf]

From: Max Reitz <mreitz@redhat.com>

To disallow certain refcount_bits values, some _unsupported_imgopts
invocations look like "refcount_bits=1[^0-9]", i.e. they match an
integer boundary with [^0-9].  This expression does not match the end of
the string, though, so it breaks down when refcount_bits is the last
option (which it tends to be after the rewrite of the check script in
Python).

Those invocations could use \b or \> instead, but those are not
portable.  They could use something like \([^0-9]\|$\), but that would
be cumbersome.  To make it simple and keep the existing invocations
working, just let _unsupported_imgopts match the regex against $IMGOPTS
plus a trailing space.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210210095128.22732-1-mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/common.rc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 77c37e8312..65cdba5723 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -885,7 +885,9 @@ _unsupported_imgopts()
 {
     for bad_opt
     do
-        if echo "$IMGOPTS" | grep -q 2>/dev/null "$bad_opt"
+        # Add a space so tests can match for whitespace that marks the
+        # end of an option (\b or \> are not portable)
+        if echo "$IMGOPTS " | grep -q 2>/dev/null "$bad_opt"
         then
             _notrun "not suitable for image option: $bad_opt"
         fi
-- 
2.29.2

[PULL 03/11] blockjob: Fix crash with IOthread when block commit after snapshot

[Kevin Wolf]

From: Michael Qiu <qiudayu@huayun.com>

Currently, if guest has workloads, IO thread will acquire aio_context
lock before do io_submit, it leads to segmentfault when do block commit
after snapshot. Just like below:

Program received signal SIGSEGV, Segmentation fault.

[Switching to Thread 0x7f7c7d91f700 (LWP 99907)]
0x00005576d0f65aab in bdrv_mirror_top_pwritev at ../block/mirror.c:1437
1437    ../block/mirror.c: No such file or directory.
(gdb) p s->job
$17 = (MirrorBlockJob *) 0x0
(gdb) p s->stop
$18 = false

Call trace of IO thread:
0  0x00005576d0f65aab in bdrv_mirror_top_pwritev at ../block/mirror.c:1437
1  0x00005576d0f7f3ab in bdrv_driver_pwritev at ../block/io.c:1174
2  0x00005576d0f8139d in bdrv_aligned_pwritev at ../block/io.c:1988
3  0x00005576d0f81b65 in bdrv_co_pwritev_part at ../block/io.c:2156
4  0x00005576d0f8e6b7 in blk_do_pwritev_part at ../block/block-backend.c:1260
5  0x00005576d0f8e84d in blk_aio_write_entry at ../block/block-backend.c:1476
...

Switch to qemu main thread:
0  0x00007f903be704ed in __lll_lock_wait at
/lib/../lib64/libpthread.so.0
1  0x00007f903be6bde6 in _L_lock_941 at /lib/../lib64/libpthread.so.0
2  0x00007f903be6bcdf in pthread_mutex_lock at
/lib/../lib64/libpthread.so.0
3  0x0000564b21456889 in qemu_mutex_lock_impl at
../util/qemu-thread-posix.c:79
4  0x0000564b213af8a5 in block_job_add_bdrv at ../blockjob.c:224
5  0x0000564b213b00ad in block_job_create at ../blockjob.c:440
6  0x0000564b21357c0a in mirror_start_job at ../block/mirror.c:1622
7  0x0000564b2135a9af in commit_active_start at ../block/mirror.c:1867
8  0x0000564b2133d132 in qmp_block_commit at ../blockdev.c:2768
9  0x0000564b2141fef3 in qmp_marshal_block_commit at
qapi/qapi-commands-block-core.c:346
10 0x0000564b214503c9 in do_qmp_dispatch_bh at
../qapi/qmp-dispatch.c:110
11 0x0000564b21451996 in aio_bh_poll at ../util/async.c:164
12 0x0000564b2146018e in aio_dispatch at ../util/aio-posix.c:381
13 0x0000564b2145187e in aio_ctx_dispatch at ../util/async.c:306
14 0x00007f9040239049 in g_main_context_dispatch at
/lib/../lib64/libglib-2.0.so.0
15 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:232
16 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:255
17 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:531
18 0x0000564b212304e1 in qemu_main_loop at ../softmmu/runstate.c:721
19 0x0000564b20f7975e in main at ../softmmu/main.c:50

In IO thread when do bdrv_mirror_top_pwritev, the job is NULL, and stop field
is false, this means the MirrorBDSOpaque "s" object has not been initialized
yet, and this object is initialized by block_job_create(), but the initialize
process is stuck in acquiring the lock.

In this situation, IO thread come to bdrv_mirror_top_pwritev(),which means that
mirror-top node is already inserted into block graph, but its bs->opaque->job
is not initialized.

The root cause is that qemu main thread do release/acquire when hold the lock,
at the same time, IO thread get the lock after release stage, and the crash
occured.

Actually, in this situation, job->job.aio_context will not equal to
qemu_get_aio_context(), and will be the same as bs->aio_context,
thus, no need to release the lock, becasue bdrv_root_attach_child()
will not change the context.

This patch fix this issue.

Fixes: 132ada80 "block: Adjust AioContexts when attaching nodes"

Signed-off-by: Michael Qiu <qiudayu@huayun.com>
Message-Id: <20210203024059.52683-1-08005325@163.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 blockjob.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index db3a21699c..f2feff051d 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -212,15 +212,19 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
                        uint64_t perm, uint64_t shared_perm, Error **errp)
 {
     BdrvChild *c;
+    bool need_context_ops;
 
     bdrv_ref(bs);
-    if (job->job.aio_context != qemu_get_aio_context()) {
+
+    need_context_ops = bdrv_get_aio_context(bs) != job->job.aio_context;
+
+    if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
         aio_context_release(job->job.aio_context);
     }
     c = bdrv_root_attach_child(bs, name, &child_job, 0,
                                job->job.aio_context, perm, shared_perm, job,
                                errp);
-    if (job->job.aio_context != qemu_get_aio_context()) {
+    if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
         aio_context_acquire(job->job.aio_context);
     }
     if (c == NULL) {
-- 
2.29.2

[PULL 04/11] hw/ide/ahci: map cmd_fis as DMA_DIRECTION_TO_DEVICE

[Kevin Wolf]

From: Alexander Bulekov <alxndr@bu.edu>

cmd_fis is mapped as DMA_DIRECTION_FROM_DEVICE, however, it is read
from, and not written to anywhere. Fix the DMA_DIRECTION and mark
cmd_fis as read-only in the code.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20210119164051.89268-1-alxndr@bu.edu>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/ide/ahci.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 6d50482b8d..f2c5157483 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -700,7 +700,7 @@ static void ahci_reset_port(AHCIState *s, int port)
 }
 
 /* Buffer pretty output based on a raw FIS structure. */
-static char *ahci_pretty_buffer_fis(uint8_t *fis, int cmd_len)
+static char *ahci_pretty_buffer_fis(const uint8_t *fis, int cmd_len)
 {
     int i;
     GString *s = g_string_new("FIS:");
@@ -1100,11 +1100,11 @@ static void execute_ncq_command(NCQTransferState *ncq_tfs)
 }
 
 
-static void process_ncq_command(AHCIState *s, int port, uint8_t *cmd_fis,
+static void process_ncq_command(AHCIState *s, int port, const uint8_t *cmd_fis,
                                 uint8_t slot)
 {
     AHCIDevice *ad = &s->dev[port];
-    NCQFrame *ncq_fis = (NCQFrame*)cmd_fis;
+    const NCQFrame *ncq_fis = (NCQFrame *)cmd_fis;
     uint8_t tag = ncq_fis->tag >> 3;
     NCQTransferState *ncq_tfs = &ad->ncq_tfs[tag];
     size_t size;
@@ -1185,7 +1185,7 @@ static AHCICmdHdr *get_cmd_header(AHCIState *s, uint8_t port, uint8_t slot)
 }
 
 static void handle_reg_h2d_fis(AHCIState *s, int port,
-                               uint8_t slot, uint8_t *cmd_fis)
+                               uint8_t slot, const uint8_t *cmd_fis)
 {
     IDEState *ide_state = &s->dev[port].port.ifs[0];
     AHCICmdHdr *cmd = get_cmd_header(s, port, slot);
@@ -1301,7 +1301,7 @@ static int handle_cmd(AHCIState *s, int port, uint8_t slot)
     tbl_addr = le64_to_cpu(cmd->tbl_addr);
     cmd_len = 0x80;
     cmd_fis = dma_memory_map(s->as, tbl_addr, &cmd_len,
-                             DMA_DIRECTION_FROM_DEVICE);
+                             DMA_DIRECTION_TO_DEVICE);
     if (!cmd_fis) {
         trace_handle_cmd_badfis(s, port);
         return -1;
@@ -1326,7 +1326,7 @@ static int handle_cmd(AHCIState *s, int port, uint8_t slot)
     }
 
 out:
-    dma_memory_unmap(s->as, cmd_fis, cmd_len, DMA_DIRECTION_FROM_DEVICE,
+    dma_memory_unmap(s->as, cmd_fis, cmd_len, DMA_DIRECTION_TO_DEVICE,
                      cmd_len);
 
     if (s->dev[port].port.ifs[0].status & (BUSY_STAT|DRQ_STAT)) {
-- 
2.29.2

[PULL 05/11] xen-block: fix reporting of discard feature

[Kevin Wolf]

From: Roger Pau Monne <roger.pau@citrix.com>

Linux blkfront expects both "discard-granularity" and
"discard-alignment" present on xenbus in order to properly enable the
feature, not exposing "discard-alignment" left some Linux blkfront
versions with a broken discard setup. This has also been addressed in
Linux with:

https://lore.kernel.org/lkml/20210118151528.81668-1-roger.pau@citrix.com/T/#u

Fix QEMU to report a "discard-alignment" of 0, in order for it to work
with older Linux frontends.

Reported-by: Arthur Borsboom <arthurborsboom@gmail.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Message-Id: <20210118153330.82324-1-roger.pau@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/block/xen-block.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 0e7d66c2a7..a3b69e2709 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -253,6 +253,7 @@ static void xen_block_realize(XenDevice *xendev, Error **errp)
         xen_device_backend_printf(xendev, "feature-discard", "%u", 1);
         xen_device_backend_printf(xendev, "discard-granularity", "%u",
                                   conf->discard_granularity);
+        xen_device_backend_printf(xendev, "discard-alignment", "%u", 0);
     }
 
     xen_device_backend_printf(xendev, "feature-flush-cache", "%u", 1);
-- 
2.29.2

[PULL 06/11] tests/qemu-iotests: Remove test 259 from the "auto" group

[Kevin Wolf]

From: Thomas Huth <thuth@redhat.com>

Tests in the "auto" group should support qcow2 so that they can
be run during "make check-block". Test 259 only supports "raw", so
it currently always gets skipped when running "make check-block".
Let's skip this unnecessary step and remove it from the auto group.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210215103835.1129145-1-thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/qemu-iotests/259 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/259 b/tests/qemu-iotests/259
index 76cde429c4..1b15e8fb48 100755
--- a/tests/qemu-iotests/259
+++ b/tests/qemu-iotests/259
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# group: rw auto quick
+# group: rw quick
 #
 # Test generic image creation fallback (by using NBD)
 #
-- 
2.29.2

[PULL 07/11] crypto: luks: Fix tiny memory leak

[Kevin Wolf]

From: Maxim Levitsky <mlevitsk@redhat.com>

When the underlying block device doesn't support the
bdrv_co_delete_file interface, an 'Error' object was leaked.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201217170904.946013-2-mlevitsk@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/crypto.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/crypto.c b/block/crypto.c
index aef5a5721a..b3a5275132 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -735,6 +735,8 @@ fail:
          */
         if ((r_del < 0) && (r_del != -ENOTSUP)) {
             error_report_err(local_delete_err);
+        } else {
+            error_free(local_delete_err);
         }
     }
 
-- 
2.29.2

[PULL 08/11] block: add bdrv_co_delete_file_noerr

[Kevin Wolf]

From: Maxim Levitsky <mlevitsk@redhat.com>

This function wraps bdrv_co_delete_file for the common case of removing a file,
which was just created by format driver, on an error condition.

It hides the -ENOTSUPP error, and reports all other errors otherwise.

Use it in luks driver

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20201217170904.946013-3-mlevitsk@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/block/block.h |  1 +
 block.c               | 22 ++++++++++++++++++++++
 block/crypto.c        | 15 ++-------------
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index a9b7f03f11..b3f6e509d4 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -441,6 +441,7 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base,
                               Error **errp);
 void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base);
 int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp);
+void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs);
 
 
 typedef struct BdrvCheckResult {
diff --git a/block.c b/block.c
index c682c3e3b9..a1f3cecd75 100644
--- a/block.c
+++ b/block.c
@@ -706,6 +706,28 @@ int coroutine_fn bdrv_co_delete_file(BlockDriverState *bs, Error **errp)
     return ret;
 }
 
+void coroutine_fn bdrv_co_delete_file_noerr(BlockDriverState *bs)
+{
+    Error *local_err = NULL;
+    int ret;
+
+    if (!bs) {
+        return;
+    }
+
+    ret = bdrv_co_delete_file(bs, &local_err);
+    /*
+     * ENOTSUP will happen if the block driver doesn't support
+     * the 'bdrv_co_delete_file' interface. This is a predictable
+     * scenario and shouldn't be reported back to the user.
+     */
+    if (ret == -ENOTSUP) {
+        error_free(local_err);
+    } else if (ret < 0) {
+        error_report_err(local_err);
+    }
+}
+
 /**
  * Try to get @bs's logical and physical block size.
  * On success, store them in @bsz struct and return 0.
diff --git a/block/crypto.c b/block/crypto.c
index b3a5275132..1d30fde38e 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -725,19 +725,8 @@ fail:
      * If an error occurred, delete 'filename'. Even if the file existed
      * beforehand, it has been truncated and corrupted in the process.
      */
-    if (ret && bs) {
-        Error *local_delete_err = NULL;
-        int r_del = bdrv_co_delete_file(bs, &local_delete_err);
-        /*
-         * ENOTSUP will happen if the block driver doesn't support
-         * the 'bdrv_co_delete_file' interface. This is a predictable
-         * scenario and shouldn't be reported back to the user.
-         */
-        if ((r_del < 0) && (r_del != -ENOTSUP)) {
-            error_report_err(local_delete_err);
-        } else {
-            error_free(local_delete_err);
-        }
+    if (ret) {
+        bdrv_co_delete_file_noerr(bs);
     }
 
     bdrv_unref(bs);
-- 
2.29.2

[PULL 09/11] block: qcow2: remove the created file on initialization error

[Kevin Wolf]

From: Maxim Levitsky <mlevitsk@redhat.com>

If the qcow initialization fails, we should remove the file if it was
already created, to avoid leaving stale files around.

We already do this for luks raw images.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-Id: <20201217170904.946013-4-mlevitsk@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 5d94f45be9..d9f49a52e7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3846,12 +3846,14 @@ static int coroutine_fn qcow2_co_create_opts(BlockDriver *drv,
 
     /* Create the qcow2 image (format layer) */
     ret = qcow2_co_create(create_options, errp);
+finish:
     if (ret < 0) {
-        goto finish;
+        bdrv_co_delete_file_noerr(bs);
+        bdrv_co_delete_file_noerr(data_bs);
+    } else {
+        ret = 0;
     }
 
-    ret = 0;
-finish:
     qobject_unref(qdict);
     bdrv_unref(bs);
     bdrv_unref(data_bs);
-- 
2.29.2

[PULL 10/11] monitor: Fix assertion failure on shutdown

[Kevin Wolf]

Commit 357bda95 already tried to fix the order in monitor_cleanup() by
moving shutdown of the dispatcher coroutine further to the start.
However, it didn't go far enough:

iothread_stop() makes sure that all pending work (bottom halves) in the
AioContext of the monitor iothread is completed. iothread_destroy()
depends on this and fails an assertion if there is still a pending BH.

While the dispatcher coroutine is running, it will try to resume the
monitor after taking a request out of the queue, which involves a BH.
The dispatcher is run until it terminates in the AIO_WAIT_WHILE() loop.
However, adding new BHs between iothread_stop() and iothread_destroy()
is forbidden.

Fix this by stopping the dispatcher first before shutting down the other
parts of the monitor. This means we can now receive requests that aren't
handled any more when QEMU is shutting down, but this is unlikely to be
a problem for QMP clients.

Fixes: 357bda9590784ff75803d52de43150d4107ed98e
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210212172028.288825-2-kwolf@redhat.com>
Tested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 monitor/monitor.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/monitor/monitor.c b/monitor/monitor.c
index 1e4a6b3f20..e94f532cf5 100644
--- a/monitor/monitor.c
+++ b/monitor/monitor.c
@@ -618,16 +618,6 @@ void monitor_data_destroy(Monitor *mon)
 
 void monitor_cleanup(void)
 {
-    /*
-     * We need to explicitly stop the I/O thread (but not destroy it),
-     * clean up the monitor resources, then destroy the I/O thread since
-     * we need to unregister from chardev below in
-     * monitor_data_destroy(), and chardev is not thread-safe yet
-     */
-    if (mon_iothread) {
-        iothread_stop(mon_iothread);
-    }
-
     /*
      * The dispatcher needs to stop before destroying the monitor and
      * the I/O thread.
@@ -637,6 +627,11 @@ void monitor_cleanup(void)
      * eventually terminates.  qemu_aio_context is automatically
      * polled by calling AIO_WAIT_WHILE on it, but we must poll
      * iohandler_ctx manually.
+     *
+     * Letting the iothread continue while shutting down the dispatcher
+     * means that new requests may still be coming in. This is okay,
+     * we'll just leave them in the queue without sending a response
+     * and monitor_data_destroy() will free them.
      */
     qmp_dispatcher_co_shutdown = true;
     if (!qatomic_xchg(&qmp_dispatcher_co_busy, true)) {
@@ -647,6 +642,16 @@ void monitor_cleanup(void)
                    (aio_poll(iohandler_get_aio_context(), false),
                     qatomic_mb_read(&qmp_dispatcher_co_busy)));
 
+    /*
+     * We need to explicitly stop the I/O thread (but not destroy it),
+     * clean up the monitor resources, then destroy the I/O thread since
+     * we need to unregister from chardev below in
+     * monitor_data_destroy(), and chardev is not thread-safe yet
+     */
+    if (mon_iothread) {
+        iothread_stop(mon_iothread);
+    }
+
     /* Flush output buffers and destroy monitors */
     qemu_mutex_lock(&monitor_lock);
     monitor_destroyed = true;
-- 
2.29.2

[PULL 11/11] monitor/qmp: Stop processing requests when shutdown is requested

[Kevin Wolf]

Before this patch, monitor_qmp_dispatcher_co() used to check whether
shutdown is requested only when it would have to wait for new requests.
If there were still some queued requests, it would try to execute all of
them before shutting down.

This can be surprising when the queued QMP commands take long or hang
because Ctrl-C may not actually exit QEMU as soon as possible.

Change monitor_qmp_dispatcher_co() so that it additionally checks
whether shutdown is request before it gets a new request from the queue.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210212172028.288825-3-kwolf@redhat.com>
Tested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 monitor/qmp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/monitor/qmp.c b/monitor/qmp.c
index 43880fa623..2326bd7f9b 100644
--- a/monitor/qmp.c
+++ b/monitor/qmp.c
@@ -227,6 +227,11 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data)
          */
         qatomic_mb_set(&qmp_dispatcher_co_busy, false);
 
+        /* On shutdown, don't take any more requests from the queue */
+        if (qmp_dispatcher_co_shutdown) {
+            return;
+        }
+
         while (!(req_obj = monitor_qmp_requests_pop_any_with_lock())) {
             /*
              * No more requests to process.  Wait to be reentered from
-- 
2.29.2

Re: [PULL 00/11] Block layer patches

[Peter Maydell]

On Mon, 15 Feb 2021 at 15:01, Kevin Wolf <kwolf@redhat.com> wrote:
>
> The following changes since commit 0280396a33c7210c4df5306afeab63411a41535a:
>
>   Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-gdbstub-150221-1' into staging (2021-02-15 10:13:13 +0000)
>
> are available in the Git repository at:
>
>   git://repo.or.cz/qemu/kevin.git tags/for-upstream
>
> for you to fetch changes up to b248e61652e20c3353af4b0ccb90f17d76f4db21:
>
>   monitor/qmp: Stop processing requests when shutdown is requested (2021-02-15 15:10:14 +0100)
>
> ----------------------------------------------------------------
> Block layer patches:
>
> - qemu-storage-daemon: Enable object-add
> - blockjob: Fix crash with IOthread when block commit after snapshot
> - monitor: Shutdown fixes
> - xen-block: fix reporting of discard feature
> - qcow2: Remove half-initialised image file after failed image creation
> - ahci: Fix DMA direction
> - iotests fixes
>


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/6.0
for any user-visible changes.

-- PMM