block: push recursive flushing up from drivers

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -2331,9 +2331,7 @@ void bdrv_flush_all(void)
     BlockDriverState *bs;
 
     QTAILQ_FOREACH(bs, &bdrv_states, list) {
-        if (!bdrv_is_read_only(bs) && bdrv_is_inserted(bs)) {
-            bdrv_flush(bs);
-        }
+        bdrv_flush(bs);
     }
 }
 
@@ -3520,7 +3518,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
 {
     int ret;
 
-    if (!bs->drv) {
+    if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
         return 0;
     }
 
@@ -3538,7 +3536,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
     }
 
     if (bs->drv->bdrv_co_flush_to_disk) {
-        return bs->drv->bdrv_co_flush_to_disk(bs);
+        ret = bs->drv->bdrv_co_flush_to_disk(bs);
     } else if (bs->drv->bdrv_aio_flush) {
         BlockDriverAIOCB *acb;
         CoroutineIOCompletion co = {
@@ -3547,10 +3545,10 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
 
         acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co);
         if (acb == NULL) {
-            return -EIO;
+            ret = -EIO;
         } else {
             qemu_coroutine_yield();
-            return co.ret;
+            ret = co.ret;
         }
     } else {
         /*
@@ -3564,8 +3562,16 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
          *
          * Let's hope the user knows what he's doing.
          */
-        return 0;
+        ret = 0;
     }
+    if (ret < 0) {
+        return ret;
+    }
+
+    /* Now flush the underlying protocol.  It will also have BDRV_O_NO_FLUSH
+     * in the case of cache=unsafe, so there are no useless flushes.
+     */
+    return bdrv_co_flush(bs->file);
 }
 
 void bdrv_invalidate_cache(BlockDriverState *bs)

block/blkdebug.c

@@ -397,12 +397,6 @@ static void blkdebug_close(BlockDriverState *bs)
     }
 }
 
-static BlockDriverAIOCB *blkdebug_aio_flush(BlockDriverState *bs,
-    BlockDriverCompletionFunc *cb, void *opaque)
-{
-    return bdrv_aio_flush(bs->file, cb, opaque);
-}
-
 static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
     BlkdebugVars *old_vars)
 {
@@ -452,7 +446,6 @@ static BlockDriver bdrv_blkdebug = {
 
     .bdrv_aio_readv     = blkdebug_aio_readv,
     .bdrv_aio_writev    = blkdebug_aio_writev,
-    .bdrv_aio_flush     = blkdebug_aio_flush,
 
     .bdrv_debug_event   = blkdebug_debug_event,
 };

block/cow.c

@@ -318,11 +318,6 @@ exit:
     return ret;
 }
 
-static coroutine_fn int cow_co_flush(BlockDriverState *bs)
-{
-    return bdrv_co_flush(bs->file);
-}
-
 static QEMUOptionParameter cow_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -348,7 +343,6 @@ static BlockDriver bdrv_cow = {
 
     .bdrv_read              = cow_co_read,
     .bdrv_write             = cow_co_write,
-    .bdrv_co_flush_to_disk  = cow_co_flush,
     .bdrv_co_is_allocated   = cow_co_is_allocated,
 
     .create_options = cow_create_options,

block/qcow.c

@@ -835,11 +835,6 @@ fail:
     return ret;
 }
 
-static coroutine_fn int qcow_co_flush(BlockDriverState *bs)
-{
-    return bdrv_co_flush(bs->file);
-}
-
 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     BDRVQcowState *s = bs->opaque;
@@ -877,7 +872,6 @@ static BlockDriver bdrv_qcow = {
 
     .bdrv_co_readv          = qcow_co_readv,
     .bdrv_co_writev         = qcow_co_writev,
-    .bdrv_co_flush_to_disk  = qcow_co_flush,
     .bdrv_co_is_allocated   = qcow_co_is_allocated,
 
     .bdrv_set_key           = qcow_set_key,

block/qcow2.c

@@ -1253,11 +1253,6 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
     return 0;
 }
 
-static coroutine_fn int qcow2_co_flush_to_disk(BlockDriverState *bs)
-{
-    return bdrv_co_flush(bs->file);
-}
-
 static int64_t qcow2_vm_state_offset(BDRVQcowState *s)
 {
 	return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
@@ -1377,7 +1372,6 @@ static BlockDriver bdrv_qcow2 = {
     .bdrv_co_readv          = qcow2_co_readv,
     .bdrv_co_writev         = qcow2_co_writev,
     .bdrv_co_flush_to_os    = qcow2_co_flush_to_os,
-    .bdrv_co_flush_to_disk  = qcow2_co_flush_to_disk,
 
     .bdrv_co_discard        = qcow2_co_discard,
     .bdrv_truncate          = qcow2_truncate,

block/qed.c

@@ -1350,13 +1350,6 @@ static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
                          opaque, QED_AIOCB_WRITE);
 }
 
-static BlockDriverAIOCB *bdrv_qed_aio_flush(BlockDriverState *bs,
-                                            BlockDriverCompletionFunc *cb,
-                                            void *opaque)
-{
-    return bdrv_aio_flush(bs->file, cb, opaque);
-}
-
 typedef struct {
     Coroutine *co;
     int ret;
@@ -1562,7 +1555,6 @@ static BlockDriver bdrv_qed = {
     .bdrv_make_empty          = bdrv_qed_make_empty,
     .bdrv_aio_readv           = bdrv_qed_aio_readv,
     .bdrv_aio_writev          = bdrv_qed_aio_writev,
-    .bdrv_aio_flush           = bdrv_qed_aio_flush,
     .bdrv_co_write_zeroes     = bdrv_qed_co_write_zeroes,
     .bdrv_truncate            = bdrv_qed_truncate,
     .bdrv_getlength           = bdrv_qed_getlength,

block/raw.c

@@ -25,11 +25,6 @@ static void raw_close(BlockDriverState *bs)
 {
 }
 
-static int coroutine_fn raw_co_flush(BlockDriverState *bs)
-{
-    return bdrv_co_flush(bs->file);
-}
-
 static int64_t raw_getlength(BlockDriverState *bs)
 {
     return bdrv_getlength(bs->file);
@@ -113,7 +108,6 @@ static BlockDriver bdrv_raw = {
 
     .bdrv_co_readv          = raw_co_readv,
     .bdrv_co_writev         = raw_co_writev,
-    .bdrv_co_flush_to_disk  = raw_co_flush,
     .bdrv_co_discard        = raw_co_discard,
 
     .bdrv_probe         = raw_probe,

block/vdi.c

@@ -930,13 +930,6 @@ static void vdi_close(BlockDriverState *bs)
     error_free(s->migration_blocker);
 }
 
-static coroutine_fn int vdi_co_flush(BlockDriverState *bs)
-{
-    logout("\n");
-    return bdrv_co_flush(bs->file);
-}
-
-
 static QEMUOptionParameter vdi_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -969,7 +962,6 @@ static BlockDriver bdrv_vdi = {
     .bdrv_open = vdi_open,
     .bdrv_close = vdi_close,
     .bdrv_create = vdi_create,
-    .bdrv_co_flush_to_disk = vdi_co_flush,
     .bdrv_co_is_allocated = vdi_co_is_allocated,
     .bdrv_make_empty = vdi_make_empty,
 

block/vmdk.c

@@ -1525,10 +1525,10 @@ static void vmdk_close(BlockDriverState *bs)
 
 static coroutine_fn int vmdk_co_flush(BlockDriverState *bs)
 {
-    int i, ret, err;
     BDRVVmdkState *s = bs->opaque;
+    int i, err;
+    int ret = 0;
 
-    ret = bdrv_co_flush(bs->file);
     for (i = 0; i < s->num_extents; i++) {
         err = bdrv_co_flush(s->extents[i].file);
         if (err < 0) {

block/vpc.c

@@ -507,11 +507,6 @@ static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num,
     return ret;
 }
 
-static coroutine_fn int vpc_co_flush(BlockDriverState *bs)
-{
-    return bdrv_co_flush(bs->file);
-}
-
 /*
  * Calculates the number of cylinders, heads and sectors per cylinder
  * based on a given number of sectors. This is the algorithm described
@@ -789,7 +784,6 @@ static BlockDriver bdrv_vpc = {
 
     .bdrv_read              = vpc_co_read,
     .bdrv_write             = vpc_co_write,
-    .bdrv_co_flush_to_disk  = vpc_co_flush,
 
     .create_options = vpc_create_options,
 };