[Qemu-devel] [PATCH v2 00/11] Preparation for block job mutex

[Qemu-devel] [PATCH v2 00/11] Preparation for block job mutex

[Paolo Bonzini]

These are a bunch of cleanups and patches extracted from the AioContext
lock removal series.  As a general theme, the patches reorganize
blockjob.c to follow the blockjob.h/blockjob_int.h separation more
closely.  For this reason, a lot of the patches are just moving functions
around.

The blockjob.h/blockjob_int.h split later will correspond to different
locking rules, but the patches are independent from this change, and
can be applied/reviewed separately.

There is no code change from v1, but all patches now have Reviewed-by
from at least one of John and Stefan.

Thanks,

Paolo


Paolo Bonzini (11):
  blockjob: remove unnecessary check
  blockjob: remove iostatus_reset callback
  blockjob: introduce block_job_early_fail
  blockjob: introduce block_job_pause/resume_all
  blockjob: separate monitor and blockjob APIs
  blockjob: move iostatus reset inside block_job_user_resume
  blockjob: introduce block_job_cancel_async, check iostatus invariants
  blockjob: group BlockJob transaction functions together
  blockjob: strengthen a bit test-blockjob-txn
  blockjob: reorganize block_job_completed_txn_abort
  blockjob: use deferred_to_main_loop to indicate the coroutine has
    ended

 block/backup.c               |   2 +-
 block/commit.c               |   2 +-
 block/io.c                   |  19 +-
 block/mirror.c               |   2 +-
 blockdev.c                   |   1 -
 blockjob.c                   | 900 +++++++++++++++++++++++--------------------
 include/block/blockjob.h     |  16 -
 include/block/blockjob_int.h |  27 +-
 tests/test-blockjob-txn.c    |   7 +-
 tests/test-blockjob.c        |  10 +-
 10 files changed, 522 insertions(+), 464 deletions(-)

-- 
2.12.2

[Qemu-devel] [PATCH 01/11] blockjob: remove unnecessary check

[Paolo Bonzini]

!job is always checked prior to the call, drop it from here.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blockjob.c b/blockjob.c
index 6e489327ff..23022b3331 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -480,7 +480,7 @@ static bool block_job_should_pause(BlockJob *job)
 
 bool block_job_user_paused(BlockJob *job)
 {
-    return job ? job->user_paused : 0;
+    return job->user_paused;
 }
 
 void coroutine_fn block_job_pause_point(BlockJob *job)
-- 
2.12.2

[Qemu-devel] [PATCH 02/11] blockjob: remove iostatus_reset callback

[Paolo Bonzini]

This is unused since commit 66a0fae ("blockjob: Don't touch BDS iostatus",
2016-05-19).

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c                   | 3 ---
 include/block/blockjob_int.h | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 23022b3331..71187d0c9e 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -555,9 +555,6 @@ bool block_job_is_cancelled(BlockJob *job)
 void block_job_iostatus_reset(BlockJob *job)
 {
     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
-    if (job->driver->iostatus_reset) {
-        job->driver->iostatus_reset(job);
-    }
 }
 
 static int block_job_finish_sync(BlockJob *job,
diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index 3f86cc5acc..bfcc5d1241 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -44,9 +44,6 @@ struct BlockJobDriver {
     /** Optional callback for job types that support setting a speed limit */
     void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
 
-    /** Optional callback for job types that need to forward I/O status reset */
-    void (*iostatus_reset)(BlockJob *job);
-
     /** Mandatory: Entrypoint for the Coroutine. */
     CoroutineEntry *start;
 
-- 
2.12.2

[Qemu-devel] [PATCH 03/11] blockjob: introduce block_job_early_fail

[Paolo Bonzini]

Outside blockjob.c, block_job_unref is only used when a block job fails
to start, and block_job_ref is not used at all.  The reference counting
thus is pretty well hidden.  Introduce a separate function to be used
by block jobs; because block_job_ref and block_job_unref now become
static, move them earlier in blockjob.c.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/backup.c               |  2 +-
 block/commit.c               |  2 +-
 block/mirror.c               |  2 +-
 blockjob.c                   | 47 ++++++++++++++++++++++++++------------------
 include/block/blockjob_int.h | 15 +++-----------
 tests/test-blockjob.c        | 10 +++++-----
 6 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index a4fb2884f9..5387fbd84e 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -692,7 +692,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     }
     if (job) {
         backup_clean(&job->common);
-        block_job_unref(&job->common);
+        block_job_early_fail(&job->common);
     }
 
     return NULL;
diff --git a/block/commit.c b/block/commit.c
index 91d2c344f6..99e41c6e50 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -426,7 +426,7 @@ fail:
     if (commit_top_bs) {
         bdrv_set_backing_hd(overlay_bs, top, &error_abort);
     }
-    block_job_unref(&s->common);
+    block_job_early_fail(&s->common);
 }
 
 
diff --git a/block/mirror.c b/block/mirror.c
index 9f5eb692fd..6a6619ca71 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1252,7 +1252,7 @@ fail:
 
         g_free(s->replaces);
         blk_unref(s->target);
-        block_job_unref(&s->common);
+        block_job_early_fail(&s->common);
     }
 
     bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
diff --git a/blockjob.c b/blockjob.c
index 71187d0c9e..5a722c3635 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -106,6 +106,32 @@ BlockJob *block_job_get(const char *id)
     return NULL;
 }
 
+static void block_job_ref(BlockJob *job)
+{
+    ++job->refcnt;
+}
+
+static void block_job_attached_aio_context(AioContext *new_context,
+                                           void *opaque);
+static void block_job_detach_aio_context(void *opaque);
+
+static void block_job_unref(BlockJob *job)
+{
+    if (--job->refcnt == 0) {
+        BlockDriverState *bs = blk_bs(job->blk);
+        bs->job = NULL;
+        block_job_remove_all_bdrv(job);
+        blk_remove_aio_context_notifier(job->blk,
+                                        block_job_attached_aio_context,
+                                        block_job_detach_aio_context, job);
+        blk_unref(job->blk);
+        error_free(job->blocker);
+        g_free(job->id);
+        QLIST_REMOVE(job, job_list);
+        g_free(job);
+    }
+}
+
 static void block_job_attached_aio_context(AioContext *new_context,
                                            void *opaque)
 {
@@ -293,26 +319,9 @@ void block_job_start(BlockJob *job)
     bdrv_coroutine_enter(blk_bs(job->blk), job->co);
 }
 
-void block_job_ref(BlockJob *job)
-{
-    ++job->refcnt;
-}
-
-void block_job_unref(BlockJob *job)
+void block_job_early_fail(BlockJob *job)
 {
-    if (--job->refcnt == 0) {
-        BlockDriverState *bs = blk_bs(job->blk);
-        bs->job = NULL;
-        block_job_remove_all_bdrv(job);
-        blk_remove_aio_context_notifier(job->blk,
-                                        block_job_attached_aio_context,
-                                        block_job_detach_aio_context, job);
-        blk_unref(job->blk);
-        error_free(job->blocker);
-        g_free(job->id);
-        QLIST_REMOVE(job, job_list);
-        g_free(job);
-    }
+    block_job_unref(job);
 }
 
 static void block_job_completed_single(BlockJob *job)
diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index bfcc5d1241..45cdfd4ac1 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -156,21 +156,12 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
 void block_job_yield(BlockJob *job);
 
 /**
- * block_job_ref:
+ * block_job_early_fail:
  * @bs: The block device.
  *
- * Grab a reference to the block job. Should be paired with block_job_unref.
+ * The block job could not be started, free it.
  */
-void block_job_ref(BlockJob *job);
-
-/**
- * block_job_unref:
- * @bs: The block device.
- *
- * Release reference to the block job and release resources if it is the last
- * reference.
- */
-void block_job_unref(BlockJob *job);
+void block_job_early_fail(BlockJob *job);
 
 /**
  * block_job_completed:
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index 740e740398..23bdf1a932 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -116,11 +116,11 @@ static void test_job_ids(void)
     job[1] = do_test_id(blk[1], "id0", false);
 
     /* But once job[0] finishes we can reuse its ID */
-    block_job_unref(job[0]);
+    block_job_early_fail(job[0]);
     job[1] = do_test_id(blk[1], "id0", true);
 
     /* No job ID specified, defaults to the backend name ('drive1') */
-    block_job_unref(job[1]);
+    block_job_early_fail(job[1]);
     job[1] = do_test_id(blk[1], NULL, true);
 
     /* Duplicate job ID */
@@ -133,9 +133,9 @@ static void test_job_ids(void)
     /* This one is valid */
     job[2] = do_test_id(blk[2], "id_2", true);
 
-    block_job_unref(job[0]);
-    block_job_unref(job[1]);
-    block_job_unref(job[2]);
+    block_job_early_fail(job[0]);
+    block_job_early_fail(job[1]);
+    block_job_early_fail(job[2]);
 
     destroy_blk(blk[0]);
     destroy_blk(blk[1]);
-- 
2.12.2

[Qemu-devel] [PATCH 04/11] blockjob: introduce block_job_pause/resume_all

[Paolo Bonzini]

Remove use of block_job_pause/resume from outside blockjob.c, thus
making them static.  The new functions are used by the block layer,
so place them in blockjob_int.h.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block/io.c                   |  19 ++------
 blockjob.c                   | 114 ++++++++++++++++++++++++++-----------------
 include/block/blockjob.h     |  16 ------
 include/block/blockjob_int.h |  14 ++++++
 4 files changed, 86 insertions(+), 77 deletions(-)

diff --git a/block/io.c b/block/io.c
index a7142e00e8..a54e5c8cea 100644
--- a/block/io.c
+++ b/block/io.c
@@ -26,6 +26,7 @@
 #include "trace.h"
 #include "sysemu/block-backend.h"
 #include "block/blockjob.h"
+#include "block/blockjob_int.h"
 #include "block/block_int.h"
 #include "qemu/cutils.h"
 #include "qapi/error.h"
@@ -301,16 +302,9 @@ void bdrv_drain_all_begin(void)
     bool waited = true;
     BlockDriverState *bs;
     BdrvNextIterator it;
-    BlockJob *job = NULL;
     GSList *aio_ctxs = NULL, *ctx;
 
-    while ((job = block_job_next(job))) {
-        AioContext *aio_context = blk_get_aio_context(job->blk);
-
-        aio_context_acquire(aio_context);
-        block_job_pause(job);
-        aio_context_release(aio_context);
-    }
+    block_job_pause_all();
 
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         AioContext *aio_context = bdrv_get_aio_context(bs);
@@ -354,7 +348,6 @@ void bdrv_drain_all_end(void)
 {
     BlockDriverState *bs;
     BdrvNextIterator it;
-    BlockJob *job = NULL;
 
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         AioContext *aio_context = bdrv_get_aio_context(bs);
@@ -365,13 +358,7 @@ void bdrv_drain_all_end(void)
         aio_context_release(aio_context);
     }
 
-    while ((job = block_job_next(job))) {
-        AioContext *aio_context = blk_get_aio_context(job->blk);
-
-        aio_context_acquire(aio_context);
-        block_job_resume(job);
-        aio_context_release(aio_context);
-    }
+    block_job_resume_all();
 }
 
 void bdrv_drain_all(void)
diff --git a/blockjob.c b/blockjob.c
index 5a722c3635..85ad610cae 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -55,36 +55,6 @@ struct BlockJobTxn {
 
 static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
 
-static char *child_job_get_parent_desc(BdrvChild *c)
-{
-    BlockJob *job = c->opaque;
-    return g_strdup_printf("%s job '%s'",
-                           BlockJobType_lookup[job->driver->job_type],
-                           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)
-{
-    BlockJob *job = opaque;
-    block_job_pause(job);
-}
-
-static void block_job_drained_end(void *opaque)
-{
-    BlockJob *job = opaque;
-    block_job_resume(job);
-}
-
-static const BlockDevOps block_job_dev_ops = {
-    .drained_begin = block_job_drained_begin,
-    .drained_end = block_job_drained_end,
-};
-
 BlockJob *block_job_next(BlockJob *job)
 {
     if (!job) {
@@ -106,6 +76,21 @@ BlockJob *block_job_get(const char *id)
     return NULL;
 }
 
+static void block_job_pause(BlockJob *job)
+{
+    job->pause_count++;
+}
+
+static void block_job_resume(BlockJob *job)
+{
+    assert(job->pause_count > 0);
+    job->pause_count--;
+    if (job->pause_count) {
+        return;
+    }
+    block_job_enter(job);
+}
+
 static void block_job_ref(BlockJob *job)
 {
     ++job->refcnt;
@@ -171,6 +156,36 @@ static void block_job_detach_aio_context(void *opaque)
     block_job_unref(job);
 }
 
+static char *child_job_get_parent_desc(BdrvChild *c)
+{
+    BlockJob *job = c->opaque;
+    return g_strdup_printf("%s job '%s'",
+                           BlockJobType_lookup[job->driver->job_type],
+                           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)
+{
+    BlockJob *job = opaque;
+    block_job_pause(job);
+}
+
+static void block_job_drained_end(void *opaque)
+{
+    BlockJob *job = opaque;
+    block_job_resume(job);
+}
+
+static const BlockDevOps block_job_dev_ops = {
+    .drained_begin = block_job_drained_begin,
+    .drained_end = block_job_drained_end,
+};
+
 void block_job_remove_all_bdrv(BlockJob *job)
 {
     GSList *l;
@@ -471,11 +486,6 @@ void block_job_complete(BlockJob *job, Error **errp)
     job->driver->complete(job, errp);
 }
 
-void block_job_pause(BlockJob *job)
-{
-    job->pause_count++;
-}
-
 void block_job_user_pause(BlockJob *job)
 {
     job->user_paused = true;
@@ -520,16 +530,6 @@ void coroutine_fn block_job_pause_point(BlockJob *job)
     }
 }
 
-void block_job_resume(BlockJob *job)
-{
-    assert(job->pause_count > 0);
-    job->pause_count--;
-    if (job->pause_count) {
-        return;
-    }
-    block_job_enter(job);
-}
-
 void block_job_user_resume(BlockJob *job)
 {
     if (job && job->user_paused && job->pause_count > 0) {
@@ -723,6 +723,30 @@ static void block_job_event_completed(BlockJob *job, const char *msg)
                                         &error_abort);
 }
 
+void block_job_pause_all(void)
+{
+    BlockJob *job = NULL;
+    while ((job = block_job_next(job))) {
+        AioContext *aio_context = blk_get_aio_context(job->blk);
+
+        aio_context_acquire(aio_context);
+        block_job_pause(job);
+        aio_context_release(aio_context);
+    }
+}
+
+void block_job_resume_all(void)
+{
+    BlockJob *job = NULL;
+    while ((job = block_job_next(job))) {
+        AioContext *aio_context = blk_get_aio_context(job->blk);
+
+        aio_context_acquire(aio_context);
+        block_job_resume(job);
+        aio_context_release(aio_context);
+    }
+}
+
 void block_job_event_ready(BlockJob *job)
 {
     job->ready = true;
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 9e906f7d7e..09c7c694b5 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -235,14 +235,6 @@ void block_job_complete(BlockJob *job, Error **errp);
 BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
 
 /**
- * block_job_pause:
- * @job: The job to be paused.
- *
- * Asynchronously pause the specified job.
- */
-void block_job_pause(BlockJob *job);
-
-/**
  * block_job_user_pause:
  * @job: The job to be paused.
  *
@@ -260,14 +252,6 @@ void block_job_user_pause(BlockJob *job);
 bool block_job_user_paused(BlockJob *job);
 
 /**
- * block_job_resume:
- * @job: The job to be resumed.
- *
- * Resume the specified job.  Must be paired with a preceding block_job_pause.
- */
-void block_job_resume(BlockJob *job);
-
-/**
  * block_job_user_resume:
  * @job: The job to be resumed.
  *
diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index 45cdfd4ac1..4f2d2ac75a 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -156,6 +156,20 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
 void block_job_yield(BlockJob *job);
 
 /**
+ * block_job_pause_all:
+ *
+ * Asynchronously pause all jobs.
+ */
+void block_job_pause_all(void);
+
+/**
+ * block_job_resume_all:
+ *
+ * Resume all block jobs.  Must be paired with a preceding block_job_pause_all.
+ */
+void block_job_resume_all(void);
+
+/**
  * block_job_early_fail:
  * @bs: The block device.
  *
-- 
2.12.2

[Qemu-devel] [PATCH 05/11] blockjob: separate monitor and blockjob APIs

[Paolo Bonzini]

We have two different headers for block job operations, blockjob.h
and blockjob_int.h.  The former contains APIs called by the monitor,
the latter contains APIs called by the block job drivers and the
block layer itself.

Keep the two APIs separate in the blockjob.c file too.  This will
be useful when transitioning away from the AioContext lock, because
there will be locking policies for the two categories, too---the
monitor will have to call new block_job_lock/unlock APIs, while blockjob
APIs will take care of this for the users.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c | 390 ++++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 205 insertions(+), 185 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 85ad610cae..41dc2fe9f1 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -55,6 +55,21 @@ struct BlockJobTxn {
 
 static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
 
+/*
+ * The block job API is composed of two categories of functions.
+ *
+ * The first includes functions used by the monitor.  The monitor is
+ * peculiar in that it accesses the block job list with block_job_get, and
+ * therefore needs consistency across block_job_get and the actual operation
+ * (e.g. block_job_set_speed).  The consistency is achieved with
+ * aio_context_acquire/release.  These functions are declared in blockjob.h.
+ *
+ * The second includes functions used by the block job drivers and sometimes
+ * by the core block layer.  These do not care about locking, because the
+ * whole coroutine runs under the AioContext lock, and are declared in
+ * blockjob_int.h.
+ */
+
 BlockJob *block_job_next(BlockJob *job)
 {
     if (!job) {
@@ -216,90 +231,6 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
     return 0;
 }
 
-void *block_job_create(const char *job_id, const BlockJobDriver *driver,
-                       BlockDriverState *bs, uint64_t perm,
-                       uint64_t shared_perm, int64_t speed, int flags,
-                       BlockCompletionFunc *cb, void *opaque, Error **errp)
-{
-    BlockBackend *blk;
-    BlockJob *job;
-    int ret;
-
-    if (bs->job) {
-        error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
-        return NULL;
-    }
-
-    if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
-        job_id = bdrv_get_device_name(bs);
-        if (!*job_id) {
-            error_setg(errp, "An explicit job ID is required for this node");
-            return NULL;
-        }
-    }
-
-    if (job_id) {
-        if (flags & BLOCK_JOB_INTERNAL) {
-            error_setg(errp, "Cannot specify job ID for internal block job");
-            return NULL;
-        }
-
-        if (!id_wellformed(job_id)) {
-            error_setg(errp, "Invalid job ID '%s'", job_id);
-            return NULL;
-        }
-
-        if (block_job_get(job_id)) {
-            error_setg(errp, "Job ID '%s' already in use", job_id);
-            return NULL;
-        }
-    }
-
-    blk = blk_new(perm, shared_perm);
-    ret = blk_insert_bs(blk, bs, errp);
-    if (ret < 0) {
-        blk_unref(blk);
-        return NULL;
-    }
-
-    job = g_malloc0(driver->instance_size);
-    job->driver        = driver;
-    job->id            = g_strdup(job_id);
-    job->blk           = blk;
-    job->cb            = cb;
-    job->opaque        = opaque;
-    job->busy          = false;
-    job->paused        = true;
-    job->pause_count   = 1;
-    job->refcnt        = 1;
-
-    error_setg(&job->blocker, "block device is in use by block job: %s",
-               BlockJobType_lookup[driver->job_type]);
-    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);
-
-    blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
-                                 block_job_detach_aio_context, job);
-
-    /* Only set speed when necessary to avoid NotSupported error */
-    if (speed != 0) {
-        Error *local_err = NULL;
-
-        block_job_set_speed(job, speed, &local_err);
-        if (local_err) {
-            block_job_unref(job);
-            error_propagate(errp, local_err);
-            return NULL;
-        }
-    }
-    return job;
-}
-
 bool block_job_is_internal(BlockJob *job)
 {
     return (job->id == NULL);
@@ -334,11 +265,6 @@ void block_job_start(BlockJob *job)
     bdrv_coroutine_enter(blk_bs(job->blk), job->co);
 }
 
-void block_job_early_fail(BlockJob *job)
-{
-    block_job_unref(job);
-}
-
 static void block_job_completed_single(BlockJob *job)
 {
     if (!job->ret) {
@@ -440,21 +366,6 @@ static void block_job_completed_txn_success(BlockJob *job)
     }
 }
 
-void block_job_completed(BlockJob *job, int ret)
-{
-    assert(blk_bs(job->blk)->job == job);
-    assert(!job->completed);
-    job->completed = true;
-    job->ret = ret;
-    if (!job->txn) {
-        block_job_completed_single(job);
-    } else if (ret < 0 || block_job_is_cancelled(job)) {
-        block_job_completed_txn_abort(job);
-    } else {
-        block_job_completed_txn_success(job);
-    }
-}
-
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
 {
     Error *local_err = NULL;
@@ -492,44 +403,11 @@ void block_job_user_pause(BlockJob *job)
     block_job_pause(job);
 }
 
-static bool block_job_should_pause(BlockJob *job)
-{
-    return job->pause_count > 0;
-}
-
 bool block_job_user_paused(BlockJob *job)
 {
     return job->user_paused;
 }
 
-void coroutine_fn block_job_pause_point(BlockJob *job)
-{
-    assert(job && block_job_started(job));
-
-    if (!block_job_should_pause(job)) {
-        return;
-    }
-    if (block_job_is_cancelled(job)) {
-        return;
-    }
-
-    if (job->driver->pause) {
-        job->driver->pause(job);
-    }
-
-    if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
-        job->paused = true;
-        job->busy = false;
-        qemu_coroutine_yield(); /* wait for block_job_resume() */
-        job->busy = true;
-        job->paused = false;
-    }
-
-    if (job->driver->resume) {
-        job->driver->resume(job);
-    }
-}
-
 void block_job_user_resume(BlockJob *job)
 {
     if (job && job->user_paused && job->pause_count > 0) {
@@ -538,13 +416,6 @@ void block_job_user_resume(BlockJob *job)
     }
 }
 
-void block_job_enter(BlockJob *job)
-{
-    if (job->co && !job->busy) {
-        bdrv_coroutine_enter(blk_bs(job->blk), job->co);
-    }
-}
-
 void block_job_cancel(BlockJob *job)
 {
     if (block_job_started(job)) {
@@ -556,11 +427,6 @@ void block_job_cancel(BlockJob *job)
     }
 }
 
-bool block_job_is_cancelled(BlockJob *job)
-{
-    return job->cancelled;
-}
-
 void block_job_iostatus_reset(BlockJob *job)
 {
     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
@@ -628,42 +494,6 @@ int block_job_complete_sync(BlockJob *job, Error **errp)
     return block_job_finish_sync(job, &block_job_complete, errp);
 }
 
-void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
-{
-    assert(job->busy);
-
-    /* Check cancellation *before* setting busy = false, too!  */
-    if (block_job_is_cancelled(job)) {
-        return;
-    }
-
-    job->busy = false;
-    if (!block_job_should_pause(job)) {
-        co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
-    }
-    job->busy = true;
-
-    block_job_pause_point(job);
-}
-
-void block_job_yield(BlockJob *job)
-{
-    assert(job->busy);
-
-    /* Check cancellation *before* setting busy = false, too!  */
-    if (block_job_is_cancelled(job)) {
-        return;
-    }
-
-    job->busy = false;
-    if (!block_job_should_pause(job)) {
-        qemu_coroutine_yield();
-    }
-    job->busy = true;
-
-    block_job_pause_point(job);
-}
-
 BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
 {
     BlockJobInfo *info;
@@ -723,6 +553,95 @@ static void block_job_event_completed(BlockJob *job, const char *msg)
                                         &error_abort);
 }
 
+/*
+ * API for block job drivers and the block layer.  These functions are
+ * declared in blockjob_int.h.
+ */
+
+void *block_job_create(const char *job_id, const BlockJobDriver *driver,
+                       BlockDriverState *bs, uint64_t perm,
+                       uint64_t shared_perm, int64_t speed, int flags,
+                       BlockCompletionFunc *cb, void *opaque, Error **errp)
+{
+    BlockBackend *blk;
+    BlockJob *job;
+    int ret;
+
+    if (bs->job) {
+        error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
+        return NULL;
+    }
+
+    if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
+        job_id = bdrv_get_device_name(bs);
+        if (!*job_id) {
+            error_setg(errp, "An explicit job ID is required for this node");
+            return NULL;
+        }
+    }
+
+    if (job_id) {
+        if (flags & BLOCK_JOB_INTERNAL) {
+            error_setg(errp, "Cannot specify job ID for internal block job");
+            return NULL;
+        }
+
+        if (!id_wellformed(job_id)) {
+            error_setg(errp, "Invalid job ID '%s'", job_id);
+            return NULL;
+        }
+
+        if (block_job_get(job_id)) {
+            error_setg(errp, "Job ID '%s' already in use", job_id);
+            return NULL;
+        }
+    }
+
+    blk = blk_new(perm, shared_perm);
+    ret = blk_insert_bs(blk, bs, errp);
+    if (ret < 0) {
+        blk_unref(blk);
+        return NULL;
+    }
+
+    job = g_malloc0(driver->instance_size);
+    job->driver        = driver;
+    job->id            = g_strdup(job_id);
+    job->blk           = blk;
+    job->cb            = cb;
+    job->opaque        = opaque;
+    job->busy          = false;
+    job->paused        = true;
+    job->pause_count   = 1;
+    job->refcnt        = 1;
+
+    error_setg(&job->blocker, "block device is in use by block job: %s",
+               BlockJobType_lookup[driver->job_type]);
+    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);
+
+    blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
+                                 block_job_detach_aio_context, job);
+
+    /* Only set speed when necessary to avoid NotSupported error */
+    if (speed != 0) {
+        Error *local_err = NULL;
+
+        block_job_set_speed(job, speed, &local_err);
+        if (local_err) {
+            block_job_unref(job);
+            error_propagate(errp, local_err);
+            return NULL;
+        }
+    }
+    return job;
+}
+
 void block_job_pause_all(void)
 {
     BlockJob *job = NULL;
@@ -735,6 +654,59 @@ void block_job_pause_all(void)
     }
 }
 
+void block_job_early_fail(BlockJob *job)
+{
+    block_job_unref(job);
+}
+
+void block_job_completed(BlockJob *job, int ret)
+{
+    assert(blk_bs(job->blk)->job == job);
+    assert(!job->completed);
+    job->completed = true;
+    job->ret = ret;
+    if (!job->txn) {
+        block_job_completed_single(job);
+    } else if (ret < 0 || block_job_is_cancelled(job)) {
+        block_job_completed_txn_abort(job);
+    } else {
+        block_job_completed_txn_success(job);
+    }
+}
+
+static bool block_job_should_pause(BlockJob *job)
+{
+    return job->pause_count > 0;
+}
+
+void coroutine_fn block_job_pause_point(BlockJob *job)
+{
+    assert(job && block_job_started(job));
+
+    if (!block_job_should_pause(job)) {
+        return;
+    }
+    if (block_job_is_cancelled(job)) {
+        return;
+    }
+
+    if (job->driver->pause) {
+        job->driver->pause(job);
+    }
+
+    if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
+        job->paused = true;
+        job->busy = false;
+        qemu_coroutine_yield(); /* wait for block_job_resume() */
+        job->busy = true;
+        job->paused = false;
+    }
+
+    if (job->driver->resume) {
+        job->driver->resume(job);
+    }
+}
+
 void block_job_resume_all(void)
 {
     BlockJob *job = NULL;
@@ -747,6 +719,54 @@ void block_job_resume_all(void)
     }
 }
 
+void block_job_enter(BlockJob *job)
+{
+    if (job->co && !job->busy) {
+        bdrv_coroutine_enter(blk_bs(job->blk), job->co);
+    }
+}
+
+bool block_job_is_cancelled(BlockJob *job)
+{
+    return job->cancelled;
+}
+
+void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
+{
+    assert(job->busy);
+
+    /* Check cancellation *before* setting busy = false, too!  */
+    if (block_job_is_cancelled(job)) {
+        return;
+    }
+
+    job->busy = false;
+    if (!block_job_should_pause(job)) {
+        co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
+    }
+    job->busy = true;
+
+    block_job_pause_point(job);
+}
+
+void block_job_yield(BlockJob *job)
+{
+    assert(job->busy);
+
+    /* Check cancellation *before* setting busy = false, too!  */
+    if (block_job_is_cancelled(job)) {
+        return;
+    }
+
+    job->busy = false;
+    if (!block_job_should_pause(job)) {
+        qemu_coroutine_yield();
+    }
+    job->busy = true;
+
+    block_job_pause_point(job);
+}
+
 void block_job_event_ready(BlockJob *job)
 {
     job->ready = true;
-- 
2.12.2

[Qemu-devel] [PATCH 06/11] blockjob: move iostatus reset inside block_job_user_resume

[Paolo Bonzini]

Outside blockjob.c, the block_job_iostatus_reset function is used once
in the monitor and once in BlockBackend.  When we introduce the block
job mutex, block_job_iostatus_reset's client is going to be the block
layer (for which blockjob.c will take the block job mutex) rather than
the monitor (which will take the block job mutex by itself).

The monitor's call to block_job_iostatus_reset from the monitor comes
just before the sole call to block_job_user_resume, so reset the
iostatus directly from block_job_iostatus_reset.  This will avoid
the need to introduce separate block_job_iostatus_reset and
block_job_iostatus_reset_locked APIs.

After making this change, move the function together with the others
that were moved in the previous patch.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockdev.c |  1 -
 blockjob.c | 11 ++++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 64282065d8..cdec4ac82a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3726,7 +3726,6 @@ void qmp_block_job_resume(const char *device, Error **errp)
     }
 
     trace_qmp_block_job_resume(job);
-    block_job_iostatus_reset(job);
     block_job_user_resume(job);
     aio_context_release(aio_context);
 }
diff --git a/blockjob.c b/blockjob.c
index 41dc2fe9f1..7edf779adc 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -412,6 +412,7 @@ void block_job_user_resume(BlockJob *job)
 {
     if (job && job->user_paused && job->pause_count > 0) {
         job->user_paused = false;
+        block_job_iostatus_reset(job);
         block_job_resume(job);
     }
 }
@@ -427,11 +428,6 @@ void block_job_cancel(BlockJob *job)
     }
 }
 
-void block_job_iostatus_reset(BlockJob *job)
-{
-    job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
-}
-
 static int block_job_finish_sync(BlockJob *job,
                                  void (*finish)(BlockJob *, Error **errp),
                                  Error **errp)
@@ -767,6 +763,11 @@ void block_job_yield(BlockJob *job)
     block_job_pause_point(job);
 }
 
+void block_job_iostatus_reset(BlockJob *job)
+{
+    job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
+}
+
 void block_job_event_ready(BlockJob *job)
 {
     job->ready = true;
-- 
2.12.2

[Qemu-devel] [PATCH 07/11] blockjob: introduce block_job_cancel_async, check iostatus invariants

[Paolo Bonzini]

The new functions helps respecting the invariant that the coroutine
is entered with false user_resume, zero pause count and no error
recorded in the iostatus.

Resetting the iostatus is now common to all of block_job_cancel_async,
block_job_user_resume and block_job_iostatus_reset, albeit with slight
differences:

- block_job_cancel_async resets the iostatus, and resumes the job if
there was an error, but the coroutine is not restarted immediately.
For example the caller may continue with a call to block_job_finish_sync.

- block_job_user_resume resets the iostatus.  It wants to resume the job
unconditionally, even if there was no error.

- block_job_iostatus_reset doesn't resume the job at all.  Maybe that's
a bug but it should be fixed separately.

block_job_iostatus_reset does the least common denominator, so add some
checking but otherwise leave it as the entry point for resetting the
iostatus.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 7edf779adc..9a5204346f 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -304,6 +304,19 @@ static void block_job_completed_single(BlockJob *job)
     block_job_unref(job);
 }
 
+static void block_job_cancel_async(BlockJob *job)
+{
+    if (job->iostatus != BLOCK_DEVICE_IO_STATUS_OK) {
+        block_job_iostatus_reset(job);
+    }
+    if (job->user_paused) {
+        /* Do not call block_job_enter here, the caller will handle it.  */
+        job->user_paused = false;
+        job->pause_count--;
+    }
+    job->cancelled = true;
+}
+
 static void block_job_completed_txn_abort(BlockJob *job)
 {
     AioContext *ctx;
@@ -328,7 +341,7 @@ static void block_job_completed_txn_abort(BlockJob *job)
              * them; this job, however, may or may not be cancelled, depending
              * on the caller, so leave it. */
             if (other_job != job) {
-                other_job->cancelled = true;
+                block_job_cancel_async(other_job);
             }
             continue;
         }
@@ -411,8 +424,8 @@ bool block_job_user_paused(BlockJob *job)
 void block_job_user_resume(BlockJob *job)
 {
     if (job && job->user_paused && job->pause_count > 0) {
-        job->user_paused = false;
         block_job_iostatus_reset(job);
+        job->user_paused = false;
         block_job_resume(job);
     }
 }
@@ -420,8 +433,7 @@ void block_job_user_resume(BlockJob *job)
 void block_job_cancel(BlockJob *job)
 {
     if (block_job_started(job)) {
-        job->cancelled = true;
-        block_job_iostatus_reset(job);
+        block_job_cancel_async(job);
         block_job_enter(job);
     } else {
         block_job_completed(job, -ECANCELED);
@@ -765,6 +777,10 @@ void block_job_yield(BlockJob *job)
 
 void block_job_iostatus_reset(BlockJob *job)
 {
+    if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
+        return;
+    }
+    assert(job->user_paused && job->pause_count > 0);
     job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
 }
 
-- 
2.12.2

[Qemu-devel] [PATCH 08/11] blockjob: group BlockJob transaction functions together

[Paolo Bonzini]

Yet another pure code movement patch, preparing for the next change.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c | 128 ++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 64 insertions(+), 64 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 9a5204346f..68efed9042 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -91,6 +91,39 @@ BlockJob *block_job_get(const char *id)
     return NULL;
 }
 
+BlockJobTxn *block_job_txn_new(void)
+{
+    BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
+    QLIST_INIT(&txn->jobs);
+    txn->refcnt = 1;
+    return txn;
+}
+
+static void block_job_txn_ref(BlockJobTxn *txn)
+{
+    txn->refcnt++;
+}
+
+void block_job_txn_unref(BlockJobTxn *txn)
+{
+    if (txn && --txn->refcnt == 0) {
+        g_free(txn);
+    }
+}
+
+void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
+{
+    if (!txn) {
+        return;
+    }
+
+    assert(!job->txn);
+    job->txn = txn;
+
+    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
+    block_job_txn_ref(txn);
+}
+
 static void block_job_pause(BlockJob *job)
 {
     job->pause_count++;
@@ -317,6 +350,37 @@ static void block_job_cancel_async(BlockJob *job)
     job->cancelled = true;
 }
 
+static int block_job_finish_sync(BlockJob *job,
+                                 void (*finish)(BlockJob *, Error **errp),
+                                 Error **errp)
+{
+    Error *local_err = NULL;
+    int ret;
+
+    assert(blk_bs(job->blk)->job == job);
+
+    block_job_ref(job);
+
+    finish(job, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        block_job_unref(job);
+        return -EBUSY;
+    }
+    /* block_job_drain calls block_job_enter, and it should be enough to
+     * induce progress until the job completes or moves to the main thread.
+    */
+    while (!job->deferred_to_main_loop && !job->completed) {
+        block_job_drain(job);
+    }
+    while (!job->completed) {
+        aio_poll(qemu_get_aio_context(), true);
+    }
+    ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
+    block_job_unref(job);
+    return ret;
+}
+
 static void block_job_completed_txn_abort(BlockJob *job)
 {
     AioContext *ctx;
@@ -440,37 +504,6 @@ void block_job_cancel(BlockJob *job)
     }
 }
 
-static int block_job_finish_sync(BlockJob *job,
-                                 void (*finish)(BlockJob *, Error **errp),
-                                 Error **errp)
-{
-    Error *local_err = NULL;
-    int ret;
-
-    assert(blk_bs(job->blk)->job == job);
-
-    block_job_ref(job);
-
-    finish(job, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        block_job_unref(job);
-        return -EBUSY;
-    }
-    /* block_job_drain calls block_job_enter, and it should be enough to
-     * induce progress until the job completes or moves to the main thread.
-    */
-    while (!job->deferred_to_main_loop && !job->completed) {
-        block_job_drain(job);
-    }
-    while (!job->completed) {
-        aio_poll(qemu_get_aio_context(), true);
-    }
-    ret = (job->cancelled && job->ret == 0) ? -ECANCELED : job->ret;
-    block_job_unref(job);
-    return ret;
-}
-
 /* A wrapper around block_job_cancel() taking an Error ** parameter so it may be
  * used with block_job_finish_sync() without the need for (rather nasty)
  * function pointer casts there. */
@@ -883,36 +916,3 @@ void block_job_defer_to_main_loop(BlockJob *job,
     aio_bh_schedule_oneshot(qemu_get_aio_context(),
                             block_job_defer_to_main_loop_bh, data);
 }
-
-BlockJobTxn *block_job_txn_new(void)
-{
-    BlockJobTxn *txn = g_new0(BlockJobTxn, 1);
-    QLIST_INIT(&txn->jobs);
-    txn->refcnt = 1;
-    return txn;
-}
-
-static void block_job_txn_ref(BlockJobTxn *txn)
-{
-    txn->refcnt++;
-}
-
-void block_job_txn_unref(BlockJobTxn *txn)
-{
-    if (txn && --txn->refcnt == 0) {
-        g_free(txn);
-    }
-}
-
-void block_job_txn_add_job(BlockJobTxn *txn, BlockJob *job)
-{
-    if (!txn) {
-        return;
-    }
-
-    assert(!job->txn);
-    job->txn = txn;
-
-    QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
-    block_job_txn_ref(txn);
-}
-- 
2.12.2

[Qemu-devel] [PATCH 09/11] blockjob: strengthen a bit test-blockjob-txn

[Paolo Bonzini]

Unlike test-blockjob-txn, QMP releases the reference to the transaction
before the jobs finish.  Thus, qemu-iotest 124 showed a failure while
working on the next patch that the unit tests did not have.  Make
the test a little nastier.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 tests/test-blockjob-txn.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index 0f80194e85..c77343fc04 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -167,6 +167,11 @@ static void test_pair_jobs(int expected1, int expected2)
     block_job_start(job1);
     block_job_start(job2);
 
+    /* Release our reference now to trigger as many nice
+     * use-after-free bugs as possible.
+     */
+    block_job_txn_unref(txn);
+
     if (expected1 == -ECANCELED) {
         block_job_cancel(job1);
     }
@@ -187,8 +192,6 @@ static void test_pair_jobs(int expected1, int expected2)
 
     g_assert_cmpint(result1, ==, expected1);
     g_assert_cmpint(result2, ==, expected2);
-
-    block_job_txn_unref(txn);
 }
 
 static void test_pair_jobs_success(void)
-- 
2.12.2

[Qemu-devel] [PATCH 10/11] blockjob: reorganize block_job_completed_txn_abort

[Paolo Bonzini]

This splits the part that touches job states from the part that invokes
callbacks.  It will make the code simpler to understand once job states will
be protected by a different mutex than the AioContext lock.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 68efed9042..436f178224 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -300,6 +300,8 @@ void block_job_start(BlockJob *job)
 
 static void block_job_completed_single(BlockJob *job)
 {
+    assert(job->completed);
+
     if (!job->ret) {
         if (job->driver->commit) {
             job->driver->commit(job);
@@ -361,7 +363,9 @@ static int block_job_finish_sync(BlockJob *job,
 
     block_job_ref(job);
 
-    finish(job, &local_err);
+    if (finish) {
+        finish(job, &local_err);
+    }
     if (local_err) {
         error_propagate(errp, local_err);
         block_job_unref(job);
@@ -385,7 +389,7 @@ static void block_job_completed_txn_abort(BlockJob *job)
 {
     AioContext *ctx;
     BlockJobTxn *txn = job->txn;
-    BlockJob *other_job, *next;
+    BlockJob *other_job;
 
     if (txn->aborting) {
         /*
@@ -394,29 +398,34 @@ static void block_job_completed_txn_abort(BlockJob *job)
         return;
     }
     txn->aborting = true;
+    block_job_txn_ref(txn);
+
     /* We are the first failed job. Cancel other jobs. */
     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
         ctx = blk_get_aio_context(other_job->blk);
         aio_context_acquire(ctx);
     }
+
+    /* Other jobs are effectively cancelled by us, set the status for
+     * them; this job, however, may or may not be cancelled, depending
+     * on the caller, so leave it. */
     QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
-        if (other_job == job || other_job->completed) {
-            /* Other jobs are "effectively" cancelled by us, set the status for
-             * them; this job, however, may or may not be cancelled, depending
-             * on the caller, so leave it. */
-            if (other_job != job) {
-                block_job_cancel_async(other_job);
-            }
-            continue;
+        if (other_job != job) {
+            block_job_cancel_async(other_job);
         }
-        block_job_cancel_sync(other_job);
-        assert(other_job->completed);
     }
-    QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
+    while (!QLIST_EMPTY(&txn->jobs)) {
+        other_job = QLIST_FIRST(&txn->jobs);
         ctx = blk_get_aio_context(other_job->blk);
+        if (!other_job->completed) {
+            assert(other_job->cancelled);
+            block_job_finish_sync(other_job, NULL, NULL);
+        }
         block_job_completed_single(other_job);
         aio_context_release(ctx);
     }
+
+    block_job_txn_unref(txn);
 }
 
 static void block_job_completed_txn_success(BlockJob *job)
-- 
2.12.2

[Qemu-devel] [PATCH 11/11] blockjob: use deferred_to_main_loop to indicate the coroutine has ended

[Paolo Bonzini]

All block jobs are using block_job_defer_to_main_loop as the final
step just before the coroutine terminates.  At this point,
block_job_enter should do nothing, but currently it restarts
the freed coroutine.

Now, the job->co states should probably be changed to an enum
(e.g. BEFORE_START, STARTED, YIELDED, COMPLETED) subsuming
block_job_started, job->deferred_to_main_loop and job->busy.
For now, this patch eliminates the problematic reenter by
removing the reset of job->deferred_to_main_loop (which served
no purpose, as far as I could see) and checking the flag in
block_job_enter.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 blockjob.c                   | 10 ++++++++--
 include/block/blockjob_int.h |  3 ++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/blockjob.c b/blockjob.c
index 436f178224..5c7da96cb9 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -771,7 +771,14 @@ void block_job_resume_all(void)
 
 void block_job_enter(BlockJob *job)
 {
-    if (job->co && !job->busy) {
+    if (!block_job_started(job)) {
+        return;
+    }
+    if (job->deferred_to_main_loop) {
+        return;
+    }
+
+    if (!job->busy) {
         bdrv_coroutine_enter(blk_bs(job->blk), job->co);
     }
 }
@@ -899,7 +906,6 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
         aio_context_acquire(aio_context);
     }
 
-    data->job->deferred_to_main_loop = false;
     data->fn(data->job, data->opaque);
 
     if (aio_context != data->aio_context) {
diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index 4f2d2ac75a..f13ad05c0d 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -241,7 +241,8 @@ typedef void BlockJobDeferToMainLoopFn(BlockJob *job, void *opaque);
  * @fn: The function to run in the main loop
  * @opaque: The opaque value that is passed to @fn
  *
- * Execute a given function in the main loop with the BlockDriverState
+ * This function must be called by the main job coroutine just before it
+ * returns.  @fn is executed in the main loop with the BlockDriverState
  * AioContext acquired.  Block jobs must call bdrv_unref(), bdrv_close(), and
  * anything that uses bdrv_drain_all() in the main loop.
  *
-- 
2.12.2

Re: [Qemu-devel] [PATCH 01/11] blockjob: remove unnecessary check

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:00PM +0200, Paolo Bonzini wrote:
> !job is always checked prior to the call, drop it from here.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  blockjob.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/blockjob.c b/blockjob.c
> index 6e489327ff..23022b3331 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -480,7 +480,7 @@ static bool block_job_should_pause(BlockJob *job)
>  
>  bool block_job_user_paused(BlockJob *job)
>  {
> -    return job ? job->user_paused : 0;
> +    return job->user_paused;
>  }
>  
>  void coroutine_fn block_job_pause_point(BlockJob *job)
> -- 
> 2.12.2
> 
>
Reviewed-by: Jeff Cody <jcody@redhat.com>

Re: [Qemu-devel] [PATCH 02/11] blockjob: remove iostatus_reset callback

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:01PM +0200, Paolo Bonzini wrote:
> This is unused since commit 66a0fae ("blockjob: Don't touch BDS iostatus",
> 2016-05-19).
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  blockjob.c                   | 3 ---
>  include/block/blockjob_int.h | 3 ---
>  2 files changed, 6 deletions(-)
> 
> diff --git a/blockjob.c b/blockjob.c
> index 23022b3331..71187d0c9e 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -555,9 +555,6 @@ bool block_job_is_cancelled(BlockJob *job)
>  void block_job_iostatus_reset(BlockJob *job)
>  {
>      job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
> -    if (job->driver->iostatus_reset) {
> -        job->driver->iostatus_reset(job);
> -    }
>  }
>  
>  static int block_job_finish_sync(BlockJob *job,
> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
> index 3f86cc5acc..bfcc5d1241 100644
> --- a/include/block/blockjob_int.h
> +++ b/include/block/blockjob_int.h
> @@ -44,9 +44,6 @@ struct BlockJobDriver {
>      /** Optional callback for job types that support setting a speed limit */
>      void (*set_speed)(BlockJob *job, int64_t speed, Error **errp);
>  
> -    /** Optional callback for job types that need to forward I/O status reset */
> -    void (*iostatus_reset)(BlockJob *job);
> -
>      /** Mandatory: Entrypoint for the Coroutine. */
>      CoroutineEntry *start;
>  
> -- 
> 2.12.2
> 
>
Reviewed-by: Jeff Cody <jcody@redhat.com>

Re: [Qemu-devel] [PATCH 03/11] blockjob: introduce block_job_early_fail

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:02PM +0200, Paolo Bonzini wrote:
> Outside blockjob.c, block_job_unref is only used when a block job fails
> to start, and block_job_ref is not used at all.  The reference counting
> thus is pretty well hidden.  Introduce a separate function to be used
> by block jobs; because block_job_ref and block_job_unref now become
> static, move them earlier in blockjob.c.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  block/backup.c               |  2 +-
>  block/commit.c               |  2 +-
>  block/mirror.c               |  2 +-
>  blockjob.c                   | 47 ++++++++++++++++++++++++++------------------
>  include/block/blockjob_int.h | 15 +++-----------
>  tests/test-blockjob.c        | 10 +++++-----
>  6 files changed, 39 insertions(+), 39 deletions(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index a4fb2884f9..5387fbd84e 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -692,7 +692,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
>      }
>      if (job) {
>          backup_clean(&job->common);
> -        block_job_unref(&job->common);
> +        block_job_early_fail(&job->common);
>      }
>  
>      return NULL;
> diff --git a/block/commit.c b/block/commit.c
> index 91d2c344f6..99e41c6e50 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -426,7 +426,7 @@ fail:
>      if (commit_top_bs) {
>          bdrv_set_backing_hd(overlay_bs, top, &error_abort);
>      }
> -    block_job_unref(&s->common);
> +    block_job_early_fail(&s->common);
>  }
>  
>  
> diff --git a/block/mirror.c b/block/mirror.c
> index 9f5eb692fd..6a6619ca71 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -1252,7 +1252,7 @@ fail:
>  
>          g_free(s->replaces);
>          blk_unref(s->target);
> -        block_job_unref(&s->common);
> +        block_job_early_fail(&s->common);
>      }
>  
>      bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
> diff --git a/blockjob.c b/blockjob.c
> index 71187d0c9e..5a722c3635 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -106,6 +106,32 @@ BlockJob *block_job_get(const char *id)
>      return NULL;
>  }
>  
> +static void block_job_ref(BlockJob *job)
> +{
> +    ++job->refcnt;
> +}
> +
> +static void block_job_attached_aio_context(AioContext *new_context,
> +                                           void *opaque);
> +static void block_job_detach_aio_context(void *opaque);
> +
> +static void block_job_unref(BlockJob *job)
> +{
> +    if (--job->refcnt == 0) {
> +        BlockDriverState *bs = blk_bs(job->blk);
> +        bs->job = NULL;
> +        block_job_remove_all_bdrv(job);
> +        blk_remove_aio_context_notifier(job->blk,
> +                                        block_job_attached_aio_context,
> +                                        block_job_detach_aio_context, job);
> +        blk_unref(job->blk);
> +        error_free(job->blocker);
> +        g_free(job->id);
> +        QLIST_REMOVE(job, job_list);
> +        g_free(job);
> +    }
> +}
> +
>  static void block_job_attached_aio_context(AioContext *new_context,
>                                             void *opaque)
>  {
> @@ -293,26 +319,9 @@ void block_job_start(BlockJob *job)
>      bdrv_coroutine_enter(blk_bs(job->blk), job->co);
>  }
>  
> -void block_job_ref(BlockJob *job)
> -{
> -    ++job->refcnt;
> -}
> -
> -void block_job_unref(BlockJob *job)
> +void block_job_early_fail(BlockJob *job)
>  {
> -    if (--job->refcnt == 0) {
> -        BlockDriverState *bs = blk_bs(job->blk);
> -        bs->job = NULL;
> -        block_job_remove_all_bdrv(job);
> -        blk_remove_aio_context_notifier(job->blk,
> -                                        block_job_attached_aio_context,
> -                                        block_job_detach_aio_context, job);
> -        blk_unref(job->blk);
> -        error_free(job->blocker);
> -        g_free(job->id);
> -        QLIST_REMOVE(job, job_list);
> -        g_free(job);
> -    }
> +    block_job_unref(job);
>  }
>  
>  static void block_job_completed_single(BlockJob *job)
> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
> index bfcc5d1241..45cdfd4ac1 100644
> --- a/include/block/blockjob_int.h
> +++ b/include/block/blockjob_int.h
> @@ -156,21 +156,12 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
>  void block_job_yield(BlockJob *job);
>  
>  /**
> - * block_job_ref:
> + * block_job_early_fail:
>   * @bs: The block device.
>   *
> - * Grab a reference to the block job. Should be paired with block_job_unref.
> + * The block job could not be started, free it.
>   */
> -void block_job_ref(BlockJob *job);
> -
> -/**
> - * block_job_unref:
> - * @bs: The block device.
> - *
> - * Release reference to the block job and release resources if it is the last
> - * reference.
> - */
> -void block_job_unref(BlockJob *job);
> +void block_job_early_fail(BlockJob *job);
>  
>  /**
>   * block_job_completed:
> diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
> index 740e740398..23bdf1a932 100644
> --- a/tests/test-blockjob.c
> +++ b/tests/test-blockjob.c
> @@ -116,11 +116,11 @@ static void test_job_ids(void)
>      job[1] = do_test_id(blk[1], "id0", false);
>  
>      /* But once job[0] finishes we can reuse its ID */
> -    block_job_unref(job[0]);
> +    block_job_early_fail(job[0]);
>      job[1] = do_test_id(blk[1], "id0", true);
>  
>      /* No job ID specified, defaults to the backend name ('drive1') */
> -    block_job_unref(job[1]);
> +    block_job_early_fail(job[1]);
>      job[1] = do_test_id(blk[1], NULL, true);
>  
>      /* Duplicate job ID */
> @@ -133,9 +133,9 @@ static void test_job_ids(void)
>      /* This one is valid */
>      job[2] = do_test_id(blk[2], "id_2", true);
>  
> -    block_job_unref(job[0]);
> -    block_job_unref(job[1]);
> -    block_job_unref(job[2]);
> +    block_job_early_fail(job[0]);
> +    block_job_early_fail(job[1]);
> +    block_job_early_fail(job[2]);
>  
>      destroy_blk(blk[0]);
>      destroy_blk(blk[1]);
> -- 
> 2.12.2
> 
>

Reviewed-by: Jeff Cody <jcody@redhat.com>

Re: [Qemu-devel] [PATCH 04/11] blockjob: introduce block_job_pause/resume_all

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:03PM +0200, Paolo Bonzini wrote:
> Remove use of block_job_pause/resume from outside blockjob.c, thus
> making them static.  The new functions are used by the block layer,
> so place them in blockjob_int.h.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  block/io.c                   |  19 ++------
>  blockjob.c                   | 114 ++++++++++++++++++++++++++-----------------
>  include/block/blockjob.h     |  16 ------
>  include/block/blockjob_int.h |  14 ++++++
>  4 files changed, 86 insertions(+), 77 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index a7142e00e8..a54e5c8cea 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -26,6 +26,7 @@
>  #include "trace.h"
>  #include "sysemu/block-backend.h"
>  #include "block/blockjob.h"
> +#include "block/blockjob_int.h"
>  #include "block/block_int.h"
>  #include "qemu/cutils.h"
>  #include "qapi/error.h"
> @@ -301,16 +302,9 @@ void bdrv_drain_all_begin(void)
>      bool waited = true;
>      BlockDriverState *bs;
>      BdrvNextIterator it;
> -    BlockJob *job = NULL;
>      GSList *aio_ctxs = NULL, *ctx;
>  
> -    while ((job = block_job_next(job))) {
> -        AioContext *aio_context = blk_get_aio_context(job->blk);
> -
> -        aio_context_acquire(aio_context);
> -        block_job_pause(job);
> -        aio_context_release(aio_context);
> -    }
> +    block_job_pause_all();
>  
>      for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
>          AioContext *aio_context = bdrv_get_aio_context(bs);
> @@ -354,7 +348,6 @@ void bdrv_drain_all_end(void)
>  {
>      BlockDriverState *bs;
>      BdrvNextIterator it;
> -    BlockJob *job = NULL;
>  
>      for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
>          AioContext *aio_context = bdrv_get_aio_context(bs);
> @@ -365,13 +358,7 @@ void bdrv_drain_all_end(void)
>          aio_context_release(aio_context);
>      }
>  
> -    while ((job = block_job_next(job))) {
> -        AioContext *aio_context = blk_get_aio_context(job->blk);
> -
> -        aio_context_acquire(aio_context);
> -        block_job_resume(job);
> -        aio_context_release(aio_context);
> -    }
> +    block_job_resume_all();
>  }
>  
>  void bdrv_drain_all(void)
> diff --git a/blockjob.c b/blockjob.c
> index 5a722c3635..85ad610cae 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -55,36 +55,6 @@ struct BlockJobTxn {
>  
>  static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
>  
> -static char *child_job_get_parent_desc(BdrvChild *c)
> -{
> -    BlockJob *job = c->opaque;
> -    return g_strdup_printf("%s job '%s'",
> -                           BlockJobType_lookup[job->driver->job_type],
> -                           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)
> -{
> -    BlockJob *job = opaque;
> -    block_job_pause(job);
> -}
> -
> -static void block_job_drained_end(void *opaque)
> -{
> -    BlockJob *job = opaque;
> -    block_job_resume(job);
> -}
> -
> -static const BlockDevOps block_job_dev_ops = {
> -    .drained_begin = block_job_drained_begin,
> -    .drained_end = block_job_drained_end,
> -};
> -
>  BlockJob *block_job_next(BlockJob *job)
>  {
>      if (!job) {
> @@ -106,6 +76,21 @@ BlockJob *block_job_get(const char *id)
>      return NULL;
>  }
>  
> +static void block_job_pause(BlockJob *job)
> +{
> +    job->pause_count++;
> +}
> +
> +static void block_job_resume(BlockJob *job)
> +{
> +    assert(job->pause_count > 0);
> +    job->pause_count--;
> +    if (job->pause_count) {
> +        return;
> +    }
> +    block_job_enter(job);
> +}
> +
>  static void block_job_ref(BlockJob *job)
>  {
>      ++job->refcnt;
> @@ -171,6 +156,36 @@ static void block_job_detach_aio_context(void *opaque)
>      block_job_unref(job);
>  }
>  
> +static char *child_job_get_parent_desc(BdrvChild *c)
> +{
> +    BlockJob *job = c->opaque;
> +    return g_strdup_printf("%s job '%s'",
> +                           BlockJobType_lookup[job->driver->job_type],
> +                           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)
> +{
> +    BlockJob *job = opaque;
> +    block_job_pause(job);
> +}
> +
> +static void block_job_drained_end(void *opaque)
> +{
> +    BlockJob *job = opaque;
> +    block_job_resume(job);
> +}
> +
> +static const BlockDevOps block_job_dev_ops = {
> +    .drained_begin = block_job_drained_begin,
> +    .drained_end = block_job_drained_end,
> +};
> +
>  void block_job_remove_all_bdrv(BlockJob *job)
>  {
>      GSList *l;
> @@ -471,11 +486,6 @@ void block_job_complete(BlockJob *job, Error **errp)
>      job->driver->complete(job, errp);
>  }
>  
> -void block_job_pause(BlockJob *job)
> -{
> -    job->pause_count++;
> -}
> -
>  void block_job_user_pause(BlockJob *job)
>  {
>      job->user_paused = true;
> @@ -520,16 +530,6 @@ void coroutine_fn block_job_pause_point(BlockJob *job)
>      }
>  }
>  
> -void block_job_resume(BlockJob *job)
> -{
> -    assert(job->pause_count > 0);
> -    job->pause_count--;
> -    if (job->pause_count) {
> -        return;
> -    }
> -    block_job_enter(job);
> -}
> -
>  void block_job_user_resume(BlockJob *job)
>  {
>      if (job && job->user_paused && job->pause_count > 0) {
> @@ -723,6 +723,30 @@ static void block_job_event_completed(BlockJob *job, const char *msg)
>                                          &error_abort);
>  }
>  
> +void block_job_pause_all(void)
> +{
> +    BlockJob *job = NULL;
> +    while ((job = block_job_next(job))) {
> +        AioContext *aio_context = blk_get_aio_context(job->blk);
> +
> +        aio_context_acquire(aio_context);
> +        block_job_pause(job);
> +        aio_context_release(aio_context);
> +    }
> +}
> +
> +void block_job_resume_all(void)
> +{
> +    BlockJob *job = NULL;
> +    while ((job = block_job_next(job))) {
> +        AioContext *aio_context = blk_get_aio_context(job->blk);
> +
> +        aio_context_acquire(aio_context);
> +        block_job_resume(job);
> +        aio_context_release(aio_context);
> +    }
> +}
> +
>  void block_job_event_ready(BlockJob *job)
>  {
>      job->ready = true;
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index 9e906f7d7e..09c7c694b5 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -235,14 +235,6 @@ void block_job_complete(BlockJob *job, Error **errp);
>  BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
>  
>  /**
> - * block_job_pause:
> - * @job: The job to be paused.
> - *
> - * Asynchronously pause the specified job.
> - */
> -void block_job_pause(BlockJob *job);
> -
> -/**
>   * block_job_user_pause:
>   * @job: The job to be paused.
>   *
> @@ -260,14 +252,6 @@ void block_job_user_pause(BlockJob *job);
>  bool block_job_user_paused(BlockJob *job);
>  
>  /**
> - * block_job_resume:
> - * @job: The job to be resumed.
> - *
> - * Resume the specified job.  Must be paired with a preceding block_job_pause.
> - */
> -void block_job_resume(BlockJob *job);
> -
> -/**
>   * block_job_user_resume:
>   * @job: The job to be resumed.
>   *
> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
> index 45cdfd4ac1..4f2d2ac75a 100644
> --- a/include/block/blockjob_int.h
> +++ b/include/block/blockjob_int.h
> @@ -156,6 +156,20 @@ void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns);
>  void block_job_yield(BlockJob *job);
>  
>  /**
> + * block_job_pause_all:
> + *
> + * Asynchronously pause all jobs.
> + */
> +void block_job_pause_all(void);
> +
> +/**
> + * block_job_resume_all:
> + *
> + * Resume all block jobs.  Must be paired with a preceding block_job_pause_all.
> + */
> +void block_job_resume_all(void);
> +
> +/**
>   * block_job_early_fail:
>   * @bs: The block device.
>   *
> -- 
> 2.12.2
> 
>
Reviewed-by: Jeff Cody <jcody@redhat.com>

Re: [Qemu-devel] [PATCH 05/11] blockjob: separate monitor and blockjob APIs

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:04PM +0200, Paolo Bonzini wrote:
> We have two different headers for block job operations, blockjob.h
> and blockjob_int.h.  The former contains APIs called by the monitor,
> the latter contains APIs called by the block job drivers and the
> block layer itself.
> 
> Keep the two APIs separate in the blockjob.c file too.  This will
> be useful when transitioning away from the AioContext lock, because
> there will be locking policies for the two categories, too---the
> monitor will have to call new block_job_lock/unlock APIs, while blockjob
> APIs will take care of this for the users.
> 

Would it make sense to split this out into separate files, rather than
delineating it by placement in a single .c file?


> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  blockjob.c | 390 ++++++++++++++++++++++++++++++++-----------------------------
>  1 file changed, 205 insertions(+), 185 deletions(-)
> 
> diff --git a/blockjob.c b/blockjob.c
> index 85ad610cae..41dc2fe9f1 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -55,6 +55,21 @@ struct BlockJobTxn {
>  
>  static QLIST_HEAD(, BlockJob) block_jobs = QLIST_HEAD_INITIALIZER(block_jobs);
>  
> +/*
> + * The block job API is composed of two categories of functions.
> + *
> + * The first includes functions used by the monitor.  The monitor is
> + * peculiar in that it accesses the block job list with block_job_get, and
> + * therefore needs consistency across block_job_get and the actual operation
> + * (e.g. block_job_set_speed).  The consistency is achieved with
> + * aio_context_acquire/release.  These functions are declared in blockjob.h.
> + *
> + * The second includes functions used by the block job drivers and sometimes
> + * by the core block layer.  These do not care about locking, because the
> + * whole coroutine runs under the AioContext lock, and are declared in
> + * blockjob_int.h.
> + */
> +
>  BlockJob *block_job_next(BlockJob *job)
>  {
>      if (!job) {
> @@ -216,90 +231,6 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
>      return 0;
>  }
>  
> -void *block_job_create(const char *job_id, const BlockJobDriver *driver,
> -                       BlockDriverState *bs, uint64_t perm,
> -                       uint64_t shared_perm, int64_t speed, int flags,
> -                       BlockCompletionFunc *cb, void *opaque, Error **errp)
> -{
> -    BlockBackend *blk;
> -    BlockJob *job;
> -    int ret;
> -
> -    if (bs->job) {
> -        error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
> -        return NULL;
> -    }
> -
> -    if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
> -        job_id = bdrv_get_device_name(bs);
> -        if (!*job_id) {
> -            error_setg(errp, "An explicit job ID is required for this node");
> -            return NULL;
> -        }
> -    }
> -
> -    if (job_id) {
> -        if (flags & BLOCK_JOB_INTERNAL) {
> -            error_setg(errp, "Cannot specify job ID for internal block job");
> -            return NULL;
> -        }
> -
> -        if (!id_wellformed(job_id)) {
> -            error_setg(errp, "Invalid job ID '%s'", job_id);
> -            return NULL;
> -        }
> -
> -        if (block_job_get(job_id)) {
> -            error_setg(errp, "Job ID '%s' already in use", job_id);
> -            return NULL;
> -        }
> -    }
> -
> -    blk = blk_new(perm, shared_perm);
> -    ret = blk_insert_bs(blk, bs, errp);
> -    if (ret < 0) {
> -        blk_unref(blk);
> -        return NULL;
> -    }
> -
> -    job = g_malloc0(driver->instance_size);
> -    job->driver        = driver;
> -    job->id            = g_strdup(job_id);
> -    job->blk           = blk;
> -    job->cb            = cb;
> -    job->opaque        = opaque;
> -    job->busy          = false;
> -    job->paused        = true;
> -    job->pause_count   = 1;
> -    job->refcnt        = 1;
> -
> -    error_setg(&job->blocker, "block device is in use by block job: %s",
> -               BlockJobType_lookup[driver->job_type]);
> -    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);
> -
> -    blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
> -                                 block_job_detach_aio_context, job);
> -
> -    /* Only set speed when necessary to avoid NotSupported error */
> -    if (speed != 0) {
> -        Error *local_err = NULL;
> -
> -        block_job_set_speed(job, speed, &local_err);
> -        if (local_err) {
> -            block_job_unref(job);
> -            error_propagate(errp, local_err);
> -            return NULL;
> -        }
> -    }
> -    return job;
> -}
> -
>  bool block_job_is_internal(BlockJob *job)
>  {
>      return (job->id == NULL);
> @@ -334,11 +265,6 @@ void block_job_start(BlockJob *job)
>      bdrv_coroutine_enter(blk_bs(job->blk), job->co);
>  }
>  
> -void block_job_early_fail(BlockJob *job)
> -{
> -    block_job_unref(job);
> -}
> -
>  static void block_job_completed_single(BlockJob *job)
>  {
>      if (!job->ret) {
> @@ -440,21 +366,6 @@ static void block_job_completed_txn_success(BlockJob *job)
>      }
>  }
>  
> -void block_job_completed(BlockJob *job, int ret)
> -{
> -    assert(blk_bs(job->blk)->job == job);
> -    assert(!job->completed);
> -    job->completed = true;
> -    job->ret = ret;
> -    if (!job->txn) {
> -        block_job_completed_single(job);
> -    } else if (ret < 0 || block_job_is_cancelled(job)) {
> -        block_job_completed_txn_abort(job);
> -    } else {
> -        block_job_completed_txn_success(job);
> -    }
> -}
> -
>  void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
>  {
>      Error *local_err = NULL;
> @@ -492,44 +403,11 @@ void block_job_user_pause(BlockJob *job)
>      block_job_pause(job);
>  }
>  
> -static bool block_job_should_pause(BlockJob *job)
> -{
> -    return job->pause_count > 0;
> -}
> -
>  bool block_job_user_paused(BlockJob *job)
>  {
>      return job->user_paused;
>  }
>  
> -void coroutine_fn block_job_pause_point(BlockJob *job)
> -{
> -    assert(job && block_job_started(job));
> -
> -    if (!block_job_should_pause(job)) {
> -        return;
> -    }
> -    if (block_job_is_cancelled(job)) {
> -        return;
> -    }
> -
> -    if (job->driver->pause) {
> -        job->driver->pause(job);
> -    }
> -
> -    if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
> -        job->paused = true;
> -        job->busy = false;
> -        qemu_coroutine_yield(); /* wait for block_job_resume() */
> -        job->busy = true;
> -        job->paused = false;
> -    }
> -
> -    if (job->driver->resume) {
> -        job->driver->resume(job);
> -    }
> -}
> -
>  void block_job_user_resume(BlockJob *job)
>  {
>      if (job && job->user_paused && job->pause_count > 0) {
> @@ -538,13 +416,6 @@ void block_job_user_resume(BlockJob *job)
>      }
>  }
>  
> -void block_job_enter(BlockJob *job)
> -{
> -    if (job->co && !job->busy) {
> -        bdrv_coroutine_enter(blk_bs(job->blk), job->co);
> -    }
> -}
> -
>  void block_job_cancel(BlockJob *job)
>  {
>      if (block_job_started(job)) {
> @@ -556,11 +427,6 @@ void block_job_cancel(BlockJob *job)
>      }
>  }
>  
> -bool block_job_is_cancelled(BlockJob *job)
> -{
> -    return job->cancelled;
> -}
> -
>  void block_job_iostatus_reset(BlockJob *job)
>  {
>      job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
> @@ -628,42 +494,6 @@ int block_job_complete_sync(BlockJob *job, Error **errp)
>      return block_job_finish_sync(job, &block_job_complete, errp);
>  }
>  
> -void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
> -{
> -    assert(job->busy);
> -
> -    /* Check cancellation *before* setting busy = false, too!  */
> -    if (block_job_is_cancelled(job)) {
> -        return;
> -    }
> -
> -    job->busy = false;
> -    if (!block_job_should_pause(job)) {
> -        co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
> -    }
> -    job->busy = true;
> -
> -    block_job_pause_point(job);
> -}
> -
> -void block_job_yield(BlockJob *job)
> -{
> -    assert(job->busy);
> -
> -    /* Check cancellation *before* setting busy = false, too!  */
> -    if (block_job_is_cancelled(job)) {
> -        return;
> -    }
> -
> -    job->busy = false;
> -    if (!block_job_should_pause(job)) {
> -        qemu_coroutine_yield();
> -    }
> -    job->busy = true;
> -
> -    block_job_pause_point(job);
> -}
> -
>  BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
>  {
>      BlockJobInfo *info;
> @@ -723,6 +553,95 @@ static void block_job_event_completed(BlockJob *job, const char *msg)
>                                          &error_abort);
>  }
>  
> +/*
> + * API for block job drivers and the block layer.  These functions are
> + * declared in blockjob_int.h.
> + */
> +
> +void *block_job_create(const char *job_id, const BlockJobDriver *driver,
> +                       BlockDriverState *bs, uint64_t perm,
> +                       uint64_t shared_perm, int64_t speed, int flags,
> +                       BlockCompletionFunc *cb, void *opaque, Error **errp)
> +{
> +    BlockBackend *blk;
> +    BlockJob *job;
> +    int ret;
> +
> +    if (bs->job) {
> +        error_setg(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
> +        return NULL;
> +    }
> +
> +    if (job_id == NULL && !(flags & BLOCK_JOB_INTERNAL)) {
> +        job_id = bdrv_get_device_name(bs);
> +        if (!*job_id) {
> +            error_setg(errp, "An explicit job ID is required for this node");
> +            return NULL;
> +        }
> +    }
> +
> +    if (job_id) {
> +        if (flags & BLOCK_JOB_INTERNAL) {
> +            error_setg(errp, "Cannot specify job ID for internal block job");
> +            return NULL;
> +        }
> +
> +        if (!id_wellformed(job_id)) {
> +            error_setg(errp, "Invalid job ID '%s'", job_id);
> +            return NULL;
> +        }
> +
> +        if (block_job_get(job_id)) {
> +            error_setg(errp, "Job ID '%s' already in use", job_id);
> +            return NULL;
> +        }
> +    }
> +
> +    blk = blk_new(perm, shared_perm);
> +    ret = blk_insert_bs(blk, bs, errp);
> +    if (ret < 0) {
> +        blk_unref(blk);
> +        return NULL;
> +    }
> +
> +    job = g_malloc0(driver->instance_size);
> +    job->driver        = driver;
> +    job->id            = g_strdup(job_id);
> +    job->blk           = blk;
> +    job->cb            = cb;
> +    job->opaque        = opaque;
> +    job->busy          = false;
> +    job->paused        = true;
> +    job->pause_count   = 1;
> +    job->refcnt        = 1;
> +
> +    error_setg(&job->blocker, "block device is in use by block job: %s",
> +               BlockJobType_lookup[driver->job_type]);
> +    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);
> +
> +    blk_add_aio_context_notifier(blk, block_job_attached_aio_context,
> +                                 block_job_detach_aio_context, job);
> +
> +    /* Only set speed when necessary to avoid NotSupported error */
> +    if (speed != 0) {
> +        Error *local_err = NULL;
> +
> +        block_job_set_speed(job, speed, &local_err);
> +        if (local_err) {
> +            block_job_unref(job);
> +            error_propagate(errp, local_err);
> +            return NULL;
> +        }
> +    }
> +    return job;
> +}
> +
>  void block_job_pause_all(void)
>  {
>      BlockJob *job = NULL;
> @@ -735,6 +654,59 @@ void block_job_pause_all(void)
>      }
>  }
>  
> +void block_job_early_fail(BlockJob *job)
> +{
> +    block_job_unref(job);
> +}
> +
> +void block_job_completed(BlockJob *job, int ret)
> +{
> +    assert(blk_bs(job->blk)->job == job);
> +    assert(!job->completed);
> +    job->completed = true;
> +    job->ret = ret;
> +    if (!job->txn) {
> +        block_job_completed_single(job);
> +    } else if (ret < 0 || block_job_is_cancelled(job)) {
> +        block_job_completed_txn_abort(job);
> +    } else {
> +        block_job_completed_txn_success(job);
> +    }
> +}
> +
> +static bool block_job_should_pause(BlockJob *job)
> +{
> +    return job->pause_count > 0;
> +}
> +
> +void coroutine_fn block_job_pause_point(BlockJob *job)
> +{
> +    assert(job && block_job_started(job));
> +
> +    if (!block_job_should_pause(job)) {
> +        return;
> +    }
> +    if (block_job_is_cancelled(job)) {
> +        return;
> +    }
> +
> +    if (job->driver->pause) {
> +        job->driver->pause(job);
> +    }
> +
> +    if (block_job_should_pause(job) && !block_job_is_cancelled(job)) {
> +        job->paused = true;
> +        job->busy = false;
> +        qemu_coroutine_yield(); /* wait for block_job_resume() */
> +        job->busy = true;
> +        job->paused = false;
> +    }
> +
> +    if (job->driver->resume) {
> +        job->driver->resume(job);
> +    }
> +}
> +
>  void block_job_resume_all(void)
>  {
>      BlockJob *job = NULL;
> @@ -747,6 +719,54 @@ void block_job_resume_all(void)
>      }
>  }
>  
> +void block_job_enter(BlockJob *job)
> +{
> +    if (job->co && !job->busy) {
> +        bdrv_coroutine_enter(blk_bs(job->blk), job->co);
> +    }
> +}
> +
> +bool block_job_is_cancelled(BlockJob *job)
> +{
> +    return job->cancelled;
> +}
> +
> +void block_job_sleep_ns(BlockJob *job, QEMUClockType type, int64_t ns)
> +{
> +    assert(job->busy);
> +
> +    /* Check cancellation *before* setting busy = false, too!  */
> +    if (block_job_is_cancelled(job)) {
> +        return;
> +    }
> +
> +    job->busy = false;
> +    if (!block_job_should_pause(job)) {
> +        co_aio_sleep_ns(blk_get_aio_context(job->blk), type, ns);
> +    }
> +    job->busy = true;
> +
> +    block_job_pause_point(job);
> +}
> +
> +void block_job_yield(BlockJob *job)
> +{
> +    assert(job->busy);
> +
> +    /* Check cancellation *before* setting busy = false, too!  */
> +    if (block_job_is_cancelled(job)) {
> +        return;
> +    }
> +
> +    job->busy = false;
> +    if (!block_job_should_pause(job)) {
> +        qemu_coroutine_yield();
> +    }
> +    job->busy = true;
> +
> +    block_job_pause_point(job);
> +}
> +
>  void block_job_event_ready(BlockJob *job)
>  {
>      job->ready = true;
> -- 
> 2.12.2
> 
> 

Re: [Qemu-devel] [PATCH 05/11] blockjob: separate monitor and blockjob APIs

[Paolo Bonzini]

On 09/05/2017 19:06, Jeff Cody wrote:
>> Keep the two APIs separate in the blockjob.c file too.  This will
>> be useful when transitioning away from the AioContext lock, because
>> there will be locking policies for the two categories, too---the
>> monitor will have to call new block_job_lock/unlock APIs, while blockjob
>> APIs will take care of this for the users.
>
> Would it make sense to split this out into separate files, rather than
> delineating it by placement in a single .c file?

Probably not, because the latter APIs do use several static functions in
blockjob.c.  For example, block_job_early_fail calls block_job_unref,
block_job_completed calls block_job_finish_sync (via
block_job_completed_txn_abort).

Given the file is <1000 lines of code, I think it's not worth the hassle.

Paolo

Re: [Qemu-devel] [PATCH 06/11] blockjob: move iostatus reset inside block_job_user_resume

[Jeff Cody]

On Mon, May 08, 2017 at 04:13:05PM +0200, Paolo Bonzini wrote:
> Outside blockjob.c, the block_job_iostatus_reset function is used once
> in the monitor and once in BlockBackend.  When we introduce the block
> job mutex, block_job_iostatus_reset's client is going to be the block
> layer (for which blockjob.c will take the block job mutex) rather than
> the monitor (which will take the block job mutex by itself).
> 
> The monitor's call to block_job_iostatus_reset from the monitor comes
> just before the sole call to block_job_user_resume, so reset the
> iostatus directly from block_job_iostatus_reset.  This will avoid
> the need to introduce separate block_job_iostatus_reset and
> block_job_iostatus_reset_locked APIs.
> 
> After making this change, move the function together with the others
> that were moved in the previous patch.
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  blockdev.c |  1 -
>  blockjob.c | 11 ++++++-----
>  2 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 64282065d8..cdec4ac82a 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -3726,7 +3726,6 @@ void qmp_block_job_resume(const char *device, Error **errp)
>      }
>  
>      trace_qmp_block_job_resume(job);
> -    block_job_iostatus_reset(job);
>      block_job_user_resume(job);
>      aio_context_release(aio_context);
>  }
> diff --git a/blockjob.c b/blockjob.c
> index 41dc2fe9f1..7edf779adc 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -412,6 +412,7 @@ void block_job_user_resume(BlockJob *job)
>  {
>      if (job && job->user_paused && job->pause_count > 0) {
>          job->user_paused = false;
> +        block_job_iostatus_reset(job);
>          block_job_resume(job);
>      }
>  }
> @@ -427,11 +428,6 @@ void block_job_cancel(BlockJob *job)
>      }
>  }
>  
> -void block_job_iostatus_reset(BlockJob *job)
> -{
> -    job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
> -}
> -
>  static int block_job_finish_sync(BlockJob *job,
>                                   void (*finish)(BlockJob *, Error **errp),
>                                   Error **errp)
> @@ -767,6 +763,11 @@ void block_job_yield(BlockJob *job)
>      block_job_pause_point(job);
>  }
>  
> +void block_job_iostatus_reset(BlockJob *job)
> +{
> +    job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
> +}
> +
>  void block_job_event_ready(BlockJob *job)
>  {
>      job->ready = true;
> -- 
> 2.12.2
> 
>
Reviewed-by: Jeff Cody <jcody@redhat.com>

Re: [Qemu-devel] [PATCH v2 00/11] Preparation for block job mutex

[Paolo Bonzini]

Ping?

On 08/05/2017 16:12, Paolo Bonzini wrote:
> These are a bunch of cleanups and patches extracted from the AioContext
> lock removal series.  As a general theme, the patches reorganize
> blockjob.c to follow the blockjob.h/blockjob_int.h separation more
> closely.  For this reason, a lot of the patches are just moving functions
> around.
> 
> The blockjob.h/blockjob_int.h split later will correspond to different
> locking rules, but the patches are independent from this change, and
> can be applied/reviewed separately.
> 
> There is no code change from v1, but all patches now have Reviewed-by
> from at least one of John and Stefan.
> 
> Thanks,
> 
> Paolo
> 
> 
> Paolo Bonzini (11):
>   blockjob: remove unnecessary check
>   blockjob: remove iostatus_reset callback
>   blockjob: introduce block_job_early_fail
>   blockjob: introduce block_job_pause/resume_all
>   blockjob: separate monitor and blockjob APIs
>   blockjob: move iostatus reset inside block_job_user_resume
>   blockjob: introduce block_job_cancel_async, check iostatus invariants
>   blockjob: group BlockJob transaction functions together
>   blockjob: strengthen a bit test-blockjob-txn
>   blockjob: reorganize block_job_completed_txn_abort
>   blockjob: use deferred_to_main_loop to indicate the coroutine has
>     ended
> 
>  block/backup.c               |   2 +-
>  block/commit.c               |   2 +-
>  block/io.c                   |  19 +-
>  block/mirror.c               |   2 +-
>  blockdev.c                   |   1 -
>  blockjob.c                   | 900 +++++++++++++++++++++++--------------------
>  include/block/blockjob.h     |  16 -
>  include/block/blockjob_int.h |  27 +-
>  tests/test-blockjob-txn.c    |   7 +-
>  tests/test-blockjob.c        |  10 +-
>  10 files changed, 522 insertions(+), 464 deletions(-)
> 

Re: [Qemu-devel] [Qemu-block] [PATCH v2 00/11] Preparation for block job mutex

[Stefan Hajnoczi]

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On Sun, May 21, 2017 at 03:17:50PM +0200, Paolo Bonzini wrote:
> Ping?

I think this should go through Jeff's tree.

Stefan

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Re: [Qemu-devel] [PATCH v2 00/11] Preparation for block job mutex

[Jeff Cody]

On Mon, May 08, 2017 at 04:12:59PM +0200, Paolo Bonzini wrote:
> These are a bunch of cleanups and patches extracted from the AioContext
> lock removal series.  As a general theme, the patches reorganize
> blockjob.c to follow the blockjob.h/blockjob_int.h separation more
> closely.  For this reason, a lot of the patches are just moving functions
> around.
> 
> The blockjob.h/blockjob_int.h split later will correspond to different
> locking rules, but the patches are independent from this change, and
> can be applied/reviewed separately.
> 
> There is no code change from v1, but all patches now have Reviewed-by
> from at least one of John and Stefan.
> 
> Thanks,
> 
> Paolo
> 
> 
> Paolo Bonzini (11):
>   blockjob: remove unnecessary check
>   blockjob: remove iostatus_reset callback
>   blockjob: introduce block_job_early_fail
>   blockjob: introduce block_job_pause/resume_all
>   blockjob: separate monitor and blockjob APIs
>   blockjob: move iostatus reset inside block_job_user_resume
>   blockjob: introduce block_job_cancel_async, check iostatus invariants
>   blockjob: group BlockJob transaction functions together
>   blockjob: strengthen a bit test-blockjob-txn
>   blockjob: reorganize block_job_completed_txn_abort
>   blockjob: use deferred_to_main_loop to indicate the coroutine has
>     ended
> 
>  block/backup.c               |   2 +-
>  block/commit.c               |   2 +-
>  block/io.c                   |  19 +-
>  block/mirror.c               |   2 +-
>  blockdev.c                   |   1 -
>  blockjob.c                   | 900 +++++++++++++++++++++++--------------------
>  include/block/blockjob.h     |  16 -
>  include/block/blockjob_int.h |  27 +-
>  tests/test-blockjob-txn.c    |   7 +-
>  tests/test-blockjob.c        |  10 +-
>  10 files changed, 522 insertions(+), 464 deletions(-)
> 
> -- 
> 2.12.2
> 

Thanks,

Applied to my block branch:

git://github.com/codyprime/qemu-kvm-jtc block

-Jeff