[PATCH v3 0/8] Still more coroutine and various fixes in block layer

[PATCH v3 0/8] Still more coroutine and various fixes in block layer

[Emanuele Giuseppe Esposito]

This is a dump of all minor coroutine-related fixes found while looking
around and testing various things in the QEMU block layer.

Patches aim to:
- add missing coroutine_fn annotation to the functions
- simplify to avoid the typical "if in coroutine: fn()
  // else create_coroutine(fn)" already present in generated_co_wraper
  functions.
- make sure that if a BlockDriver callback is defined as coroutine_fn, then
  it is always running in a coroutine.

This serie is based on Kevin Wolf's series "block: Simplify drain".

Based-on: <20221108123738.530873-1-kwolf@redhat.com>

Emanuele
---
v3:
* Remove patch 1, base on kevin "drain semplification serie"

v2:
* clarified commit message in patches 2/3/6 on why we add coroutine_fn

Emanuele Giuseppe Esposito (8):
  block-copy: add missing coroutine_fn annotations
  nbd/server.c: add missing coroutine_fn annotations
  block-backend: replace bdrv_*_above with blk_*_above
  block: distinguish between bdrv_create running in coroutine and not
  block/vmdk: add missing coroutine_fn annotations
  block: bdrv_create_file is a coroutine_fn
  block: bdrv_create is never called in coroutine context
  block/dirty-bitmap: remove unnecessary qemu_in_coroutine() case

 block.c                            | 75 ++++++++++++++----------------
 block/block-backend.c              | 21 +++++++++
 block/block-copy.c                 | 15 +++---
 block/commit.c                     |  4 +-
 block/dirty-bitmap.c               | 66 ++++++++++++--------------
 block/vmdk.c                       | 36 +++++++-------
 include/block/block-global-state.h |  3 +-
 include/sysemu/block-backend-io.h  |  9 ++++
 nbd/server.c                       | 43 +++++++++--------
 qemu-img.c                         |  4 +-
 10 files changed, 151 insertions(+), 125 deletions(-)

-- 
2.31.1

[PATCH v3 1/8] block-copy: add missing coroutine_fn annotations

[Emanuele Giuseppe Esposito]

block_copy_reset_unallocated and block_copy_is_cluster_allocated are
only called by backup_run, a corotuine_fn itself.

Same applies to block_copy_block_status, called by
block_copy_dirty_clusters.

Therefore mark them as coroutine too.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-copy.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index bb947afdda..f33ab1d0b6 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -577,8 +577,9 @@ static coroutine_fn int block_copy_task_entry(AioTask *task)
     return ret;
 }
 
-static int block_copy_block_status(BlockCopyState *s, int64_t offset,
-                                   int64_t bytes, int64_t *pnum)
+static coroutine_fn int block_copy_block_status(BlockCopyState *s,
+                                                int64_t offset,
+                                                int64_t bytes, int64_t *pnum)
 {
     int64_t num;
     BlockDriverState *base;
@@ -613,8 +614,9 @@ static int block_copy_block_status(BlockCopyState *s, int64_t offset,
  * Check if the cluster starting at offset is allocated or not.
  * return via pnum the number of contiguous clusters sharing this allocation.
  */
-static int block_copy_is_cluster_allocated(BlockCopyState *s, int64_t offset,
-                                           int64_t *pnum)
+static int coroutine_fn block_copy_is_cluster_allocated(BlockCopyState *s,
+                                                        int64_t offset,
+                                                        int64_t *pnum)
 {
     BlockDriverState *bs = s->source->bs;
     int64_t count, total_count = 0;
@@ -669,8 +671,9 @@ void block_copy_reset(BlockCopyState *s, int64_t offset, int64_t bytes)
  * @return 0 when the cluster at @offset was unallocated,
  *         1 otherwise, and -ret on error.
  */
-int64_t block_copy_reset_unallocated(BlockCopyState *s,
-                                     int64_t offset, int64_t *count)
+int64_t coroutine_fn block_copy_reset_unallocated(BlockCopyState *s,
+                                                  int64_t offset,
+                                                  int64_t *count)
 {
     int ret;
     int64_t clusters, bytes;
-- 
2.31.1

[PATCH v3 2/8] nbd/server.c: add missing coroutine_fn annotations

[Emanuele Giuseppe Esposito]

There are probably more missing, but right now it is necessary that
we extend coroutine_fn to block{allock/status}_to_extents, because
they use bdrv_* functions calling the generated_co_wrapper API, which
checks for the qemu_in_coroutine() case.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 nbd/server.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/nbd/server.c b/nbd/server.c
index ada16089f3..e2eec0cf46 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -2141,8 +2141,9 @@ static int nbd_extent_array_add(NBDExtentArray *ea,
     return 0;
 }
 
-static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
-                                  uint64_t bytes, NBDExtentArray *ea)
+static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs,
+                                               uint64_t offset, uint64_t bytes,
+                                               NBDExtentArray *ea)
 {
     while (bytes) {
         uint32_t flags;
@@ -2168,8 +2169,9 @@ static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset,
     return 0;
 }
 
-static int blockalloc_to_extents(BlockDriverState *bs, uint64_t offset,
-                                 uint64_t bytes, NBDExtentArray *ea)
+static int coroutine_fn blockalloc_to_extents(BlockDriverState *bs,
+                                              uint64_t offset, uint64_t bytes,
+                                              NBDExtentArray *ea)
 {
     while (bytes) {
         int64_t num;
@@ -2220,11 +2222,12 @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
 }
 
 /* Get block status from the exported device and send it to the client */
-static int nbd_co_send_block_status(NBDClient *client, uint64_t handle,
-                                    BlockDriverState *bs, uint64_t offset,
-                                    uint32_t length, bool dont_fragment,
-                                    bool last, uint32_t context_id,
-                                    Error **errp)
+static int
+coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
+                                      BlockDriverState *bs, uint64_t offset,
+                                      uint32_t length, bool dont_fragment,
+                                      bool last, uint32_t context_id,
+                                      Error **errp)
 {
     int ret;
     unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS;
-- 
2.31.1

[PATCH v3 3/8] block-backend: replace bdrv_*_above with blk_*_above

[Emanuele Giuseppe Esposito]

Avoid mixing bdrv_* functions with blk_*, so create blk_* counterparts
for:
- bdrv_block_status_above
- bdrv_is_allocated_above

Note that these functions will take the rdlock, so they must always run
in a coroutine.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-backend.c             | 21 +++++++++++++++++++++
 block/commit.c                    |  4 ++--
 include/sysemu/block-backend-io.h |  9 +++++++++
 nbd/server.c                      | 28 ++++++++++++++--------------
 qemu-img.c                        |  4 ++--
 5 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 742efa7955..333d50fb3f 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1424,6 +1424,27 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
     return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags);
 }
 
+int coroutine_fn blk_block_status_above(BlockBackend *blk,
+                                        BlockDriverState *base,
+                                        int64_t offset, int64_t bytes,
+                                        int64_t *pnum, int64_t *map,
+                                        BlockDriverState **file)
+{
+    IO_CODE();
+    return bdrv_block_status_above(blk_bs(blk), base, offset, bytes, pnum, map,
+                                   file);
+}
+
+int coroutine_fn blk_is_allocated_above(BlockBackend *blk,
+                                        BlockDriverState *base,
+                                        bool include_base, int64_t offset,
+                                        int64_t bytes, int64_t *pnum)
+{
+    IO_CODE();
+    return bdrv_is_allocated_above(blk_bs(blk), base, include_base, offset,
+                                   bytes, pnum);
+}
+
 typedef struct BlkRwCo {
     BlockBackend *blk;
     int64_t offset;
diff --git a/block/commit.c b/block/commit.c
index 0029b31944..9d4d908344 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -155,8 +155,8 @@ static int coroutine_fn commit_run(Job *job, Error **errp)
             break;
         }
         /* Copy if allocated above the base */
-        ret = bdrv_is_allocated_above(blk_bs(s->top), s->base_overlay, true,
-                                      offset, COMMIT_BUFFER_SIZE, &n);
+        ret = blk_is_allocated_above(s->top, s->base_overlay, true,
+                                     offset, COMMIT_BUFFER_SIZE, &n);
         copy = (ret > 0);
         trace_commit_one_iteration(s, offset, n, ret);
         if (copy) {
diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h
index 50f5aa2e07..a47cb825e5 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -92,6 +92,15 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
                                    int64_t bytes, BdrvRequestFlags read_flags,
                                    BdrvRequestFlags write_flags);
 
+int coroutine_fn blk_block_status_above(BlockBackend *blk,
+                                        BlockDriverState *base,
+                                        int64_t offset, int64_t bytes,
+                                        int64_t *pnum, int64_t *map,
+                                        BlockDriverState **file);
+int coroutine_fn blk_is_allocated_above(BlockBackend *blk,
+                                        BlockDriverState *base,
+                                        bool include_base, int64_t offset,
+                                        int64_t bytes, int64_t *pnum);
 
 /*
  * "I/O or GS" API functions. These functions can run without
diff --git a/nbd/server.c b/nbd/server.c
index e2eec0cf46..6389b46396 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1991,7 +1991,7 @@ static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,
 }
 
 /* Do a sparse read and send the structured reply to the client.
- * Returns -errno if sending fails. bdrv_block_status_above() failure is
+ * Returns -errno if sending fails. blk_block_status_above() failure is
  * reported to the client, at which point this function succeeds.
  */
 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
@@ -2007,10 +2007,10 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,
 
     while (progress < size) {
         int64_t pnum;
-        int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL,
-                                             offset + progress,
-                                             size - progress, &pnum, NULL,
-                                             NULL);
+        int status = blk_block_status_above(exp->common.blk, NULL,
+                                            offset + progress,
+                                            size - progress, &pnum, NULL,
+                                            NULL);
         bool final;
 
         if (status < 0) {
@@ -2141,14 +2141,14 @@ static int nbd_extent_array_add(NBDExtentArray *ea,
     return 0;
 }
 
-static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs,
+static int coroutine_fn blockstatus_to_extents(BlockBackend *blk,
                                                uint64_t offset, uint64_t bytes,
                                                NBDExtentArray *ea)
 {
     while (bytes) {
         uint32_t flags;
         int64_t num;
-        int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num,
+        int ret = blk_block_status_above(blk, NULL, offset, bytes, &num,
                                           NULL, NULL);
 
         if (ret < 0) {
@@ -2169,13 +2169,13 @@ static int coroutine_fn blockstatus_to_extents(BlockDriverState *bs,
     return 0;
 }
 
-static int coroutine_fn blockalloc_to_extents(BlockDriverState *bs,
+static int coroutine_fn blockalloc_to_extents(BlockBackend *blk,
                                               uint64_t offset, uint64_t bytes,
                                               NBDExtentArray *ea)
 {
     while (bytes) {
         int64_t num;
-        int ret = bdrv_is_allocated_above(bs, NULL, false, offset, bytes,
+        int ret = blk_is_allocated_above(blk, NULL, false, offset, bytes,
                                           &num);
 
         if (ret < 0) {
@@ -2224,7 +2224,7 @@ static int nbd_co_send_extents(NBDClient *client, uint64_t handle,
 /* Get block status from the exported device and send it to the client */
 static int
 coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
-                                      BlockDriverState *bs, uint64_t offset,
+                                      BlockBackend *blk, uint64_t offset,
                                       uint32_t length, bool dont_fragment,
                                       bool last, uint32_t context_id,
                                       Error **errp)
@@ -2234,9 +2234,9 @@ coroutine_fn nbd_co_send_block_status(NBDClient *client, uint64_t handle,
     g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents);
 
     if (context_id == NBD_META_ID_BASE_ALLOCATION) {
-        ret = blockstatus_to_extents(bs, offset, length, ea);
+        ret = blockstatus_to_extents(blk, offset, length, ea);
     } else {
-        ret = blockalloc_to_extents(bs, offset, length, ea);
+        ret = blockalloc_to_extents(blk, offset, length, ea);
     }
     if (ret < 0) {
         return nbd_co_send_structured_error(
@@ -2563,7 +2563,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
 
             if (client->export_meta.base_allocation) {
                 ret = nbd_co_send_block_status(client, request->handle,
-                                               blk_bs(exp->common.blk),
+                                               exp->common.blk,
                                                request->from,
                                                request->len, dont_fragment,
                                                !--contexts_remaining,
@@ -2576,7 +2576,7 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
 
             if (client->export_meta.allocation_depth) {
                 ret = nbd_co_send_block_status(client, request->handle,
-                                               blk_bs(exp->common.blk),
+                                               exp->common.blk,
                                                request->from, request->len,
                                                dont_fragment,
                                                !--contexts_remaining,
diff --git a/qemu-img.c b/qemu-img.c
index a3b64c88af..4282a34bc0 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1730,8 +1730,8 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
         do {
             count = n * BDRV_SECTOR_SIZE;
 
-            ret = bdrv_block_status_above(src_bs, base, offset, count, &count,
-                                          NULL, NULL);
+            ret = bdrv_block_status_above(src_bs, base, offset, count,
+                                          &count, NULL, NULL);
 
             if (ret < 0) {
                 if (s->salvage) {
-- 
2.31.1

[PATCH v3 4/8] block: distinguish between bdrv_create running in coroutine and not

[Emanuele Giuseppe Esposito]

Call two different functions depending on whether bdrv_create
is in coroutine or not, following the same pattern as
generated_co_wrapper functions.

This allows to also call the coroutine function directly,
without using CreateCo or relying in bdrv_create().
It will also be useful when we add the graph rdlock to the
coroutine case.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block.c | 74 ++++++++++++++++++++++++++++-----------------------------
 1 file changed, 36 insertions(+), 38 deletions(-)

diff --git a/block.c b/block.c
index 577639c7e0..375c8056a3 100644
--- a/block.c
+++ b/block.c
@@ -528,66 +528,64 @@ typedef struct CreateCo {
     Error *err;
 } CreateCo;
 
-static void coroutine_fn bdrv_create_co_entry(void *opaque)
+static int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename,
+                                       QemuOpts *opts, Error **errp)
 {
-    Error *local_err = NULL;
     int ret;
+    GLOBAL_STATE_CODE();
+    assert(*errp == NULL);
+
+    if (!drv->bdrv_co_create_opts) {
+        error_setg(errp, "Driver '%s' does not support image creation",
+                   drv->format_name);
+        return -ENOTSUP;
+    }
+
+    ret = drv->bdrv_co_create_opts(drv, filename, opts, errp);
 
+    if (ret < 0 && !*errp) {
+        error_setg_errno(errp, -ret, "Could not create image");
+    }
+
+    return ret;
+}
+
+static void coroutine_fn bdrv_create_co_entry(void *opaque)
+{
     CreateCo *cco = opaque;
-    assert(cco->drv);
     GLOBAL_STATE_CODE();
+    assert(cco->drv);
 
-    ret = cco->drv->bdrv_co_create_opts(cco->drv,
-                                        cco->filename, cco->opts, &local_err);
-    error_propagate(&cco->err, local_err);
-    cco->ret = ret;
+    cco->ret = bdrv_co_create(cco->drv, cco->filename, cco->opts, &cco->err);
 }
 
 int bdrv_create(BlockDriver *drv, const char* filename,
                 QemuOpts *opts, Error **errp)
 {
-    int ret;
-
     GLOBAL_STATE_CODE();
 
-    Coroutine *co;
-    CreateCo cco = {
-        .drv = drv,
-        .filename = g_strdup(filename),
-        .opts = opts,
-        .ret = NOT_DONE,
-        .err = NULL,
-    };
-
-    if (!drv->bdrv_co_create_opts) {
-        error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
-        ret = -ENOTSUP;
-        goto out;
-    }
-
     if (qemu_in_coroutine()) {
         /* Fast-path if already in coroutine context */
-        bdrv_create_co_entry(&cco);
+        return bdrv_co_create(drv, filename, opts, errp);
     } else {
+        Coroutine *co;
+        CreateCo cco = {
+            .drv = drv,
+            .filename = g_strdup(filename),
+            .opts = opts,
+            .ret = NOT_DONE,
+            .err = NULL,
+        };
+
         co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
         qemu_coroutine_enter(co);
         while (cco.ret == NOT_DONE) {
             aio_poll(qemu_get_aio_context(), true);
         }
+        error_propagate(errp, cco.err);
+        g_free(cco.filename);
+        return cco.ret;
     }
-
-    ret = cco.ret;
-    if (ret < 0) {
-        if (cco.err) {
-            error_propagate(errp, cco.err);
-        } else {
-            error_setg_errno(errp, -ret, "Could not create image");
-        }
-    }
-
-out:
-    g_free(cco.filename);
-    return ret;
 }
 
 /**
-- 
2.31.1

[PATCH v3 5/8] block/vmdk: add missing coroutine_fn annotations

[Emanuele Giuseppe Esposito]

vmdk_co_create_opts() is a coroutine_fn, and calls vmdk_co_do_create()
which in turn can call two callbacks: vmdk_co_create_opts_cb and
vmdk_co_create_cb.

Mark all these functions as coroutine_fn, since vmdk_co_create_opts()
is the only caller.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/vmdk.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 26376352b9..0c32bf2e83 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -2285,10 +2285,11 @@ exit:
     return ret;
 }
 
-static int vmdk_create_extent(const char *filename, int64_t filesize,
-                              bool flat, bool compress, bool zeroed_grain,
-                              BlockBackend **pbb,
-                              QemuOpts *opts, Error **errp)
+static int coroutine_fn vmdk_create_extent(const char *filename,
+                                           int64_t filesize, bool flat,
+                                           bool compress, bool zeroed_grain,
+                                           BlockBackend **pbb,
+                                           QemuOpts *opts, Error **errp)
 {
     int ret;
     BlockBackend *blk = NULL;
@@ -2366,14 +2367,14 @@ static int filename_decompose(const char *filename, char *path, char *prefix,
  *           non-split format.
  * idx >= 1: get the n-th extent if in a split subformat
  */
-typedef BlockBackend *(*vmdk_create_extent_fn)(int64_t size,
-                                               int idx,
-                                               bool flat,
-                                               bool split,
-                                               bool compress,
-                                               bool zeroed_grain,
-                                               void *opaque,
-                                               Error **errp);
+typedef BlockBackend * coroutine_fn (*vmdk_create_extent_fn)(int64_t size,
+                                                             int idx,
+                                                             bool flat,
+                                                             bool split,
+                                                             bool compress,
+                                                             bool zeroed_grain,
+                                                             void *opaque,
+                                                             Error **errp);
 
 static void vmdk_desc_add_extent(GString *desc,
                                  const char *extent_line_fmt,
@@ -2616,7 +2617,7 @@ typedef struct {
     QemuOpts *opts;
 } VMDKCreateOptsData;
 
-static BlockBackend *vmdk_co_create_opts_cb(int64_t size, int idx,
+static BlockBackend * coroutine_fn vmdk_co_create_opts_cb(int64_t size, int idx,
                                             bool flat, bool split, bool compress,
                                             bool zeroed_grain, void *opaque,
                                             Error **errp)
@@ -2768,10 +2769,11 @@ exit:
     return ret;
 }
 
-static BlockBackend *vmdk_co_create_cb(int64_t size, int idx,
-                                       bool flat, bool split, bool compress,
-                                       bool zeroed_grain, void *opaque,
-                                       Error **errp)
+static BlockBackend * coroutine_fn vmdk_co_create_cb(int64_t size, int idx,
+                                                     bool flat, bool split,
+                                                     bool compress,
+                                                     bool zeroed_grain,
+                                                     void *opaque, Error **errp)
 {
     int ret;
     BlockDriverState *bs;
-- 
2.31.1

[PATCH v3 6/8] block: bdrv_create_file is a coroutine_fn

[Emanuele Giuseppe Esposito]

It is always called in coroutine_fn callbacks, therefore
it can directly call bdrv_co_create().

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block.c                            | 6 ++++--
 include/block/block-global-state.h | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/block.c b/block.c
index 375c8056a3..dcac28756c 100644
--- a/block.c
+++ b/block.c
@@ -533,6 +533,7 @@ static int coroutine_fn bdrv_co_create(BlockDriver *drv, const char *filename,
 {
     int ret;
     GLOBAL_STATE_CODE();
+    assert(qemu_in_coroutine());
     assert(*errp == NULL);
 
     if (!drv->bdrv_co_create_opts) {
@@ -723,7 +724,8 @@ out:
     return ret;
 }
 
-int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
+int coroutine_fn bdrv_create_file(const char *filename, QemuOpts *opts,
+                                  Error **errp)
 {
     QemuOpts *protocol_opts;
     BlockDriver *drv;
@@ -764,7 +766,7 @@ int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
         goto out;
     }
 
-    ret = bdrv_create(drv, filename, protocol_opts, errp);
+    ret = bdrv_co_create(drv, filename, protocol_opts, errp);
 out:
     qemu_opts_del(protocol_opts);
     qobject_unref(qdict);
diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h
index 00e0cf8aea..6f35ed99e3 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -57,7 +57,8 @@ BlockDriver *bdrv_find_protocol(const char *filename,
 BlockDriver *bdrv_find_format(const char *format_name);
 int bdrv_create(BlockDriver *drv, const char* filename,
                 QemuOpts *opts, Error **errp);
-int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
+int coroutine_fn bdrv_create_file(const char *filename, QemuOpts *opts,
+                                  Error **errp);
 
 BlockDriverState *bdrv_new(void);
 int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
-- 
2.31.1

[PATCH v3 7/8] block: bdrv_create is never called in coroutine context

[Emanuele Giuseppe Esposito]

Delete the if case and make sure it won't be called again
in coroutines.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block.c | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/block.c b/block.c
index dcac28756c..7a4ce7948c 100644
--- a/block.c
+++ b/block.c
@@ -563,30 +563,25 @@ static void coroutine_fn bdrv_create_co_entry(void *opaque)
 int bdrv_create(BlockDriver *drv, const char* filename,
                 QemuOpts *opts, Error **errp)
 {
+    Coroutine *co;
+    CreateCo cco = {
+        .drv = drv,
+        .filename = g_strdup(filename),
+        .opts = opts,
+        .ret = NOT_DONE,
+        .err = NULL,
+    };
     GLOBAL_STATE_CODE();
+    assert(!qemu_in_coroutine());
 
-    if (qemu_in_coroutine()) {
-        /* Fast-path if already in coroutine context */
-        return bdrv_co_create(drv, filename, opts, errp);
-    } else {
-        Coroutine *co;
-        CreateCo cco = {
-            .drv = drv,
-            .filename = g_strdup(filename),
-            .opts = opts,
-            .ret = NOT_DONE,
-            .err = NULL,
-        };
-
-        co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
-        qemu_coroutine_enter(co);
-        while (cco.ret == NOT_DONE) {
-            aio_poll(qemu_get_aio_context(), true);
-        }
-        error_propagate(errp, cco.err);
-        g_free(cco.filename);
-        return cco.ret;
+    co = qemu_coroutine_create(bdrv_create_co_entry, &cco);
+    qemu_coroutine_enter(co);
+    while (cco.ret == NOT_DONE) {
+        aio_poll(qemu_get_aio_context(), true);
     }
+    error_propagate(errp, cco.err);
+    g_free(cco.filename);
+    return cco.ret;
 }
 
 /**
-- 
2.31.1

[PATCH v3 8/8] block/dirty-bitmap: remove unnecessary qemu_in_coroutine() case

[Emanuele Giuseppe Esposito]

Some functions check if they are running in a coroutine, calling
the coroutine callback directly if it's the case.
Except that no coroutine calls such functions, therefore that case
can be removed.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/dirty-bitmap.c | 66 +++++++++++++++++++-------------------------
 1 file changed, 29 insertions(+), 37 deletions(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index bf3dc0512a..8092d08261 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -418,24 +418,20 @@ bdrv_co_remove_persistent_dirty_bitmap_entry(void *opaque)
 int bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs, const char *name,
                                         Error **errp)
 {
-    if (qemu_in_coroutine()) {
-        return bdrv_co_remove_persistent_dirty_bitmap(bs, name, errp);
-    } else {
-        Coroutine *co;
-        BdrvRemovePersistentDirtyBitmapCo s = {
-            .bs = bs,
-            .name = name,
-            .errp = errp,
-            .ret = -EINPROGRESS,
-        };
-
-        co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry,
-                                   &s);
-        bdrv_coroutine_enter(bs, co);
-        BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS);
-
-        return s.ret;
-    }
+    Coroutine *co;
+    BdrvRemovePersistentDirtyBitmapCo s = {
+        .bs = bs,
+        .name = name,
+        .errp = errp,
+        .ret = -EINPROGRESS,
+    };
+    assert(!qemu_in_coroutine());
+    co = qemu_coroutine_create(bdrv_co_remove_persistent_dirty_bitmap_entry,
+                                &s);
+    bdrv_coroutine_enter(bs, co);
+    BDRV_POLL_WHILE(bs, s.ret == -EINPROGRESS);
+
+    return s.ret;
 }
 
 bool
@@ -494,25 +490,21 @@ bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
                                      uint32_t granularity, Error **errp)
 {
     IO_CODE();
-    if (qemu_in_coroutine()) {
-        return bdrv_co_can_store_new_dirty_bitmap(bs, name, granularity, errp);
-    } else {
-        Coroutine *co;
-        BdrvCanStoreNewDirtyBitmapCo s = {
-            .bs = bs,
-            .name = name,
-            .granularity = granularity,
-            .errp = errp,
-            .in_progress = true,
-        };
-
-        co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry,
-                                   &s);
-        bdrv_coroutine_enter(bs, co);
-        BDRV_POLL_WHILE(bs, s.in_progress);
-
-        return s.ret;
-    }
+    Coroutine *co;
+    BdrvCanStoreNewDirtyBitmapCo s = {
+        .bs = bs,
+        .name = name,
+        .granularity = granularity,
+        .errp = errp,
+        .in_progress = true,
+    };
+    assert(!qemu_in_coroutine());
+    co = qemu_coroutine_create(bdrv_co_can_store_new_dirty_bitmap_entry,
+                                &s);
+    bdrv_coroutine_enter(bs, co);
+    BDRV_POLL_WHILE(bs, s.in_progress);
+
+    return s.ret;
 }
 
 void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
-- 
2.31.1

Re: [PATCH v3 0/8] Still more coroutine and various fixes in block layer

[Emanuele Giuseppe Esposito]

I apologize, as discussed also in v2 I just realized I could introduce
generated_co_wrapper_simple already here and simplify patches 6 and 8.

Also I think commit messages are the old ones from v1.

I'll resend. Please ignore this serie.

Emanuele

Am 16/11/2022 um 09:50 schrieb Emanuele Giuseppe Esposito:
> This is a dump of all minor coroutine-related fixes found while looking
> around and testing various things in the QEMU block layer.
> 
> Patches aim to:
> - add missing coroutine_fn annotation to the functions
> - simplify to avoid the typical "if in coroutine: fn()
>   // else create_coroutine(fn)" already present in generated_co_wraper
>   functions.
> - make sure that if a BlockDriver callback is defined as coroutine_fn, then
>   it is always running in a coroutine.
> 
> This serie is based on Kevin Wolf's series "block: Simplify drain".
> 
> Based-on: <20221108123738.530873-1-kwolf@redhat.com>
> 
> Emanuele
> ---
> v3:
> * Remove patch 1, base on kevin "drain semplification serie"
> 
> v2:
> * clarified commit message in patches 2/3/6 on why we add coroutine_fn
> 
> Emanuele Giuseppe Esposito (8):
>   block-copy: add missing coroutine_fn annotations
>   nbd/server.c: add missing coroutine_fn annotations
>   block-backend: replace bdrv_*_above with blk_*_above
>   block: distinguish between bdrv_create running in coroutine and not
>   block/vmdk: add missing coroutine_fn annotations
>   block: bdrv_create_file is a coroutine_fn
>   block: bdrv_create is never called in coroutine context
>   block/dirty-bitmap: remove unnecessary qemu_in_coroutine() case
> 
>  block.c                            | 75 ++++++++++++++----------------
>  block/block-backend.c              | 21 +++++++++
>  block/block-copy.c                 | 15 +++---
>  block/commit.c                     |  4 +-
>  block/dirty-bitmap.c               | 66 ++++++++++++--------------
>  block/vmdk.c                       | 36 +++++++-------
>  include/block/block-global-state.h |  3 +-
>  include/sysemu/block-backend-io.h  |  9 ++++
>  nbd/server.c                       | 43 +++++++++--------
>  qemu-img.c                         |  4 +-
>  10 files changed, 151 insertions(+), 125 deletions(-)
>