[PATCH v3 3/5] block/copy-before-write: create block_copy bitmap in filter node

Vladimir Sementsov-Ogievskiy posted 5 patches 9 months ago
Maintainers: John Snow <jsnow@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Wen Congyang <wencongyang2@huawei.com>, Xie Changlong <xiechanglong.d@gmail.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>
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[PATCH v3 3/5] block/copy-before-write: create block_copy bitmap in filter node
Posted by Vladimir Sementsov-Ogievskiy 9 months ago
Currently block_copy creates copy_bitmap in source node. But that is in
bad relation with .independent_close=true of copy-before-write filter:
source node may be detached and removed before .bdrv_close() handler
called, which should call block_copy_state_free(), which in turn should
remove copy_bitmap.

That's all not ideal: it would be better if internal bitmap of
block-copy object is not attached to any node. But that is not possible
now.

The simplest solution is just create copy_bitmap in filter node, where
anyway two other bitmaps are created.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 block/block-copy.c         |   3 +-
 block/copy-before-write.c  |   2 +-
 include/block/block-copy.h |   1 +
 tests/qemu-iotests/257.out | 112 ++++++++++++++++++-------------------
 4 files changed, 60 insertions(+), 58 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index 9ee3dd7ef5..8fca2c3698 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -351,6 +351,7 @@ static int64_t block_copy_calculate_cluster_size(BlockDriverState *target,
 }
 
 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
+                                     BlockDriverState *copy_bitmap_bs,
                                      const BdrvDirtyBitmap *bitmap,
                                      Error **errp)
 {
@@ -367,7 +368,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
         return NULL;
     }
 
-    copy_bitmap = bdrv_create_dirty_bitmap(source->bs, cluster_size, NULL,
+    copy_bitmap = bdrv_create_dirty_bitmap(copy_bitmap_bs, cluster_size, NULL,
                                            errp);
     if (!copy_bitmap) {
         return NULL;
diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index 6547eda707..44a9385aa7 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -467,7 +467,7 @@ static int cbw_open(BlockDriverState *bs, QDict *options, int flags,
             ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
              bs->file->bs->supported_zero_flags);
 
-    s->bcs = block_copy_state_new(bs->file, s->target, bitmap, errp);
+    s->bcs = block_copy_state_new(bs->file, s->target, bs, bitmap, errp);
     if (!s->bcs) {
         error_prepend(errp, "Cannot create block-copy-state: ");
         return -EINVAL;
diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index 0700953ab8..8b41643bfa 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -25,6 +25,7 @@ typedef struct BlockCopyState BlockCopyState;
 typedef struct BlockCopyCallState BlockCopyCallState;
 
 BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
+                                     BlockDriverState *copy_bitmap_bs,
                                      const BdrvDirtyBitmap *bitmap,
                                      Error **errp);
 
diff --git a/tests/qemu-iotests/257.out b/tests/qemu-iotests/257.out
index aa76131ca9..c33dd7f3a9 100644
--- a/tests/qemu-iotests/257.out
+++ b/tests/qemu-iotests/257.out
@@ -120,16 +120,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -596,16 +596,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -865,16 +865,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -1341,16 +1341,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -1610,16 +1610,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -2086,16 +2086,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -2355,16 +2355,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -2831,16 +2831,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -3100,16 +3100,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -3576,16 +3576,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -3845,16 +3845,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -4321,16 +4321,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -4590,16 +4590,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
@@ -5066,16 +5066,16 @@ write -P0x67 0x3fe0000 0x20000
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      }
-    ],
-    "drive0": [
+      },
       {
         "busy": false,
         "count": 0,
         "granularity": 65536,
         "persistent": false,
         "recording": false
-      },
+      }
+    ],
+    "drive0": [
       {
         "busy": false,
         "count": 458752,
-- 
2.34.1
Re: [PATCH v3 3/5] block/copy-before-write: create block_copy bitmap in filter node
Posted by Fiona Ebner 8 months, 3 weeks ago
Am 28.02.24 um 15:14 schrieb Vladimir Sementsov-Ogievskiy:
> Currently block_copy creates copy_bitmap in source node. But that is in
> bad relation with .independent_close=true of copy-before-write filter:
> source node may be detached and removed before .bdrv_close() handler
> called, which should call block_copy_state_free(), which in turn should
> remove copy_bitmap.
> 
> That's all not ideal: it would be better if internal bitmap of
> block-copy object is not attached to any node. But that is not possible
> now.
> 
> The simplest solution is just create copy_bitmap in filter node, where
> anyway two other bitmaps are created.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>