diff --git a/block/backup-top.h b/block/copy-before-write.h
similarity index 56%
rename from block/backup-top.h
rename to block/copy-before-write.h
index b28b0031c4..5977b7aa31 100644
--- a/block/backup-top.h
+++ b/block/copy-before-write.h
@@ -1,10 +1,10 @@
 /*
- * backup-top filter driver
+ * copy-before-write filter driver
  *
  * The driver performs Copy-Before-Write (CBW) operation: it is injected above
  * some node, and before each write it copies _old_ data to the target node.
  *
- * Copyright (c) 2018-2019 Virtuozzo International GmbH.
+ * Copyright (c) 2018-2021 Virtuozzo International GmbH.
  *
  * Author:
  *  Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
@@ -23,20 +23,20 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef BACKUP_TOP_H
-#define BACKUP_TOP_H
+#ifndef COPY_BEFORE_WRITE_H
+#define COPY_BEFORE_WRITE_H
 
 #include "block/block_int.h"
 #include "block/block-copy.h"
 
-BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
-                                         BlockDriverState *target,
-                                         const char *filter_node_name,
-                                         uint64_t cluster_size,
-                                         BackupPerf *perf,
-                                         BdrvRequestFlags write_flags,
-                                         BlockCopyState **bcs,
-                                         Error **errp);
-void bdrv_backup_top_drop(BlockDriverState *bs);
+BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
+                                  BlockDriverState *target,
+                                  const char *filter_node_name,
+                                  uint64_t cluster_size,
+                                  BackupPerf *perf,
+                                  BdrvRequestFlags write_flags,
+                                  BlockCopyState **bcs,
+                                  Error **errp);
+void bdrv_cbw_drop(BlockDriverState *bs);
 
-#endif /* BACKUP_TOP_H */
+#endif /* COPY_BEFORE_WRITE_H */
diff --git a/block/backup.c b/block/backup.c
index bd3614ce70..ac91821b08 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -27,13 +27,13 @@
 #include "qemu/bitmap.h"
 #include "qemu/error-report.h"
 
-#include "block/backup-top.h"
+#include "block/copy-before-write.h"
 
 #define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16)
 
 typedef struct BackupBlockJob {
     BlockJob common;
-    BlockDriverState *backup_top;
+    BlockDriverState *cbw;
     BlockDriverState *source_bs;
     BlockDriverState *target_bs;
 
@@ -104,7 +104,7 @@ static void backup_clean(Job *job)
 {
     BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
     block_job_remove_all_bdrv(&s->common);
-    bdrv_backup_top_drop(s->backup_top);
+    bdrv_cbw_drop(s->cbw);
 }
 
 void backup_do_checkpoint(BlockJob *job, Error **errp)
@@ -408,7 +408,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     BackupBlockJob *job = NULL;
     int64_t cluster_size;
     BdrvRequestFlags write_flags;
-    BlockDriverState *backup_top = NULL;
+    BlockDriverState *cbw = NULL;
     BlockCopyState *bcs = NULL;
 
     assert(bs);
@@ -521,22 +521,22 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     write_flags = (bdrv_chain_contains(target, bs) ? BDRV_REQ_SERIALISING : 0) |
                   (compress ? BDRV_REQ_WRITE_COMPRESSED : 0),
 
-    backup_top = bdrv_backup_top_append(bs, target, filter_node_name,
+    cbw = bdrv_cbw_append(bs, target, filter_node_name,
                                         cluster_size, perf,
                                         write_flags, &bcs, errp);
-    if (!backup_top) {
+    if (!cbw) {
         goto error;
     }
 
     /* job->len is fixed, so we can't allow resize */
-    job = block_job_create(job_id, &backup_job_driver, txn, backup_top,
+    job = block_job_create(job_id, &backup_job_driver, txn, cbw,
                            0, BLK_PERM_ALL,
                            speed, creation_flags, cb, opaque, errp);
     if (!job) {
         goto error;
     }
 
-    job->backup_top = backup_top;
+    job->cbw = cbw;
     job->source_bs = bs;
     job->target_bs = target;
     job->on_source_error = on_source_error;
@@ -552,7 +552,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     block_copy_set_progress_meter(bcs, &job->common.job.progress);
     block_copy_set_speed(bcs, speed);
 
-    /* Required permissions are already taken by backup-top target */
+    /* Required permissions are taken by copy-before-write filter target */
     block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
                        &error_abort);
 
@@ -562,8 +562,8 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     if (sync_bitmap) {
         bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL);
     }
-    if (backup_top) {
-        bdrv_backup_top_drop(backup_top);
+    if (cbw) {
+        bdrv_cbw_drop(cbw);
     }
 
     return NULL;
diff --git a/block/backup-top.c b/block/copy-before-write.c
similarity index 62%
rename from block/backup-top.c
rename to block/copy-before-write.c
index 425e3778be..0dc5a107cf 100644
--- a/block/backup-top.c
+++ b/block/copy-before-write.c
@@ -1,10 +1,10 @@
 /*
- * backup-top filter driver
+ * copy-before-write filter driver
  *
  * The driver performs Copy-Before-Write (CBW) operation: it is injected above
  * some node, and before each write it copies _old_ data to the target node.
  *
- * Copyright (c) 2018-2019 Virtuozzo International GmbH.
+ * Copyright (c) 2018-2021 Virtuozzo International GmbH.
  *
  * Author:
  *  Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
@@ -32,25 +32,25 @@
 #include "block/qdict.h"
 #include "block/block-copy.h"
 
-#include "block/backup-top.h"
+#include "block/copy-before-write.h"
 
-typedef struct BDRVBackupTopState {
+typedef struct BDRVCopyBeforeWriteState {
     BlockCopyState *bcs;
     BdrvChild *target;
     int64_t cluster_size;
-} BDRVBackupTopState;
+} BDRVCopyBeforeWriteState;
 
-static coroutine_fn int backup_top_co_preadv(
+static coroutine_fn int cbw_co_preadv(
         BlockDriverState *bs, uint64_t offset, uint64_t bytes,
         QEMUIOVector *qiov, int flags)
 {
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }
 
-static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
-                                       uint64_t bytes, BdrvRequestFlags flags)
+static coroutine_fn int cbw_do_copy_before_write(BlockDriverState *bs,
+        uint64_t offset, uint64_t bytes, BdrvRequestFlags flags)
 {
-    BDRVBackupTopState *s = bs->opaque;
+    BDRVCopyBeforeWriteState *s = bs->opaque;
     uint64_t off, end;
 
     if (flags & BDRV_REQ_WRITE_UNCHANGED) {
@@ -63,10 +63,10 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
     return block_copy(s->bcs, off, end - off, true);
 }
 
-static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
-                                               int64_t offset, int bytes)
+static int coroutine_fn cbw_co_pdiscard(BlockDriverState *bs,
+                                        int64_t offset, int bytes)
 {
-    int ret = backup_top_cbw(bs, offset, bytes, 0);
+    int ret = cbw_do_copy_before_write(bs, offset, bytes, 0);
     if (ret < 0) {
         return ret;
     }
@@ -74,10 +74,10 @@ static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
     return bdrv_co_pdiscard(bs->backing, offset, bytes);
 }
 
-static int coroutine_fn backup_top_co_pwrite_zeroes(BlockDriverState *bs,
+static int coroutine_fn cbw_co_pwrite_zeroes(BlockDriverState *bs,
         int64_t offset, int bytes, BdrvRequestFlags flags)
 {
-    int ret = backup_top_cbw(bs, offset, bytes, flags);
+    int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
     if (ret < 0) {
         return ret;
     }
@@ -85,12 +85,12 @@ static int coroutine_fn backup_top_co_pwrite_zeroes(BlockDriverState *bs,
     return bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags);
 }
 
-static coroutine_fn int backup_top_co_pwritev(BlockDriverState *bs,
-                                              uint64_t offset,
-                                              uint64_t bytes,
-                                              QEMUIOVector *qiov, int flags)
+static coroutine_fn int cbw_co_pwritev(BlockDriverState *bs,
+                                       uint64_t offset,
+                                       uint64_t bytes,
+                                       QEMUIOVector *qiov, int flags)
 {
-    int ret = backup_top_cbw(bs, offset, bytes, flags);
+    int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
     if (ret < 0) {
         return ret;
     }
@@ -98,7 +98,7 @@ static coroutine_fn int backup_top_co_pwritev(BlockDriverState *bs,
     return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
 }
 
-static int coroutine_fn backup_top_co_flush(BlockDriverState *bs)
+static int coroutine_fn cbw_co_flush(BlockDriverState *bs)
 {
     if (!bs->backing) {
         return 0;
@@ -107,7 +107,7 @@ static int coroutine_fn backup_top_co_flush(BlockDriverState *bs)
     return bdrv_co_flush(bs->backing->bs);
 }
 
-static void backup_top_refresh_filename(BlockDriverState *bs)
+static void cbw_refresh_filename(BlockDriverState *bs)
 {
     if (bs->backing == NULL) {
         /*
@@ -120,11 +120,11 @@ static void backup_top_refresh_filename(BlockDriverState *bs)
             bs->backing->bs->filename);
 }
 
-static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                  BdrvChildRole role,
-                                  BlockReopenQueue *reopen_queue,
-                                  uint64_t perm, uint64_t shared,
-                                  uint64_t *nperm, uint64_t *nshared)
+static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c,
+                           BdrvChildRole role,
+                           BlockReopenQueue *reopen_queue,
+                           uint64_t perm, uint64_t shared,
+                           uint64_t *nperm, uint64_t *nshared)
 {
     if (!(role & BDRV_CHILD_FILTERED)) {
         /*
@@ -149,41 +149,41 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
     }
 }
 
-BlockDriver bdrv_backup_top_filter = {
-    .format_name = "backup-top",
-    .instance_size = sizeof(BDRVBackupTopState),
+BlockDriver bdrv_cbw_filter = {
+    .format_name = "copy-before-write",
+    .instance_size = sizeof(BDRVCopyBeforeWriteState),
 
-    .bdrv_co_preadv             = backup_top_co_preadv,
-    .bdrv_co_pwritev            = backup_top_co_pwritev,
-    .bdrv_co_pwrite_zeroes      = backup_top_co_pwrite_zeroes,
-    .bdrv_co_pdiscard           = backup_top_co_pdiscard,
-    .bdrv_co_flush              = backup_top_co_flush,
+    .bdrv_co_preadv             = cbw_co_preadv,
+    .bdrv_co_pwritev            = cbw_co_pwritev,
+    .bdrv_co_pwrite_zeroes      = cbw_co_pwrite_zeroes,
+    .bdrv_co_pdiscard           = cbw_co_pdiscard,
+    .bdrv_co_flush              = cbw_co_flush,
 
-    .bdrv_refresh_filename      = backup_top_refresh_filename,
+    .bdrv_refresh_filename      = cbw_refresh_filename,
 
-    .bdrv_child_perm            = backup_top_child_perm,
+    .bdrv_child_perm            = cbw_child_perm,
 
     .is_filter = true,
 };
 
-BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
-                                         BlockDriverState *target,
-                                         const char *filter_node_name,
-                                         uint64_t cluster_size,
-                                         BackupPerf *perf,
-                                         BdrvRequestFlags write_flags,
-                                         BlockCopyState **bcs,
-                                         Error **errp)
+BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
+                                  BlockDriverState *target,
+                                  const char *filter_node_name,
+                                  uint64_t cluster_size,
+                                  BackupPerf *perf,
+                                  BdrvRequestFlags write_flags,
+                                  BlockCopyState **bcs,
+                                  Error **errp)
 {
     ERRP_GUARD();
     int ret;
-    BDRVBackupTopState *state;
+    BDRVCopyBeforeWriteState *state;
     BlockDriverState *top;
     bool appended = false;
 
     assert(source->total_sectors == target->total_sectors);
 
-    top = bdrv_new_open_driver(&bdrv_backup_top_filter, filter_node_name,
+    top = bdrv_new_open_driver(&bdrv_cbw_filter, filter_node_name,
                                BDRV_O_RDWR, errp);
     if (!top) {
         return NULL;
@@ -210,7 +210,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
 
     ret = bdrv_append(top, source, errp);
     if (ret < 0) {
-        error_prepend(errp, "Cannot append backup-top filter: ");
+        error_prepend(errp, "Cannot append copy-before-write filter: ");
         goto fail;
     }
     appended = true;
@@ -231,7 +231,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
 
 fail:
     if (appended) {
-        bdrv_backup_top_drop(top);
+        bdrv_cbw_drop(top);
     } else {
         bdrv_unref(top);
     }
@@ -241,9 +241,9 @@ fail:
     return NULL;
 }
 
-void bdrv_backup_top_drop(BlockDriverState *bs)
+void bdrv_cbw_drop(BlockDriverState *bs)
 {
-    BDRVBackupTopState *s = bs->opaque;
+    BDRVCopyBeforeWriteState *s = bs->opaque;
 
     bdrv_drop_filter(bs, &error_abort);
 
diff --git a/MAINTAINERS b/MAINTAINERS
index dffcb651f4..973cecc70e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2342,8 +2342,8 @@ F: block/mirror.c
 F: qapi/job.json
 F: block/block-copy.c
 F: include/block/block-copy.c
-F: block/backup-top.h
-F: block/backup-top.c
+F: block/copy-before-write.h
+F: block/copy-before-write.c
 F: include/block/aio_task.h
 F: block/aio_task.c
 F: util/qemu-co-shared-resource.c
diff --git a/block/meson.build b/block/meson.build
index 0450914c7a..66ee11e62c 100644
--- a/block/meson.build
+++ b/block/meson.build
@@ -4,7 +4,7 @@ block_ss.add(files(
   'aio_task.c',
   'amend.c',
   'backup.c',
-  'backup-top.c',
+  'copy-before-write.c',
   'blkdebug.c',
   'blklogwrites.c',
   'blkverify.c',
diff --git a/tests/qemu-iotests/283 b/tests/qemu-iotests/283
index 010c22f0a2..a09e0183ae 100755
--- a/tests/qemu-iotests/283
+++ b/tests/qemu-iotests/283
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # group: auto quick
 #
-# Test for backup-top filter permission activation failure
+# Test for copy-before-write filter permission conflict
 #
 # Copyright (c) 2019 Virtuozzo International GmbH.
 #
@@ -31,13 +31,13 @@ size = 1024 * 1024
 """ Test description
 
 When performing a backup, all writes on the source subtree must go through the
-backup-top filter so it can copy all data to the target before it is changed.
-backup-top filter is appended above source node, to achieve this thing, so all
-parents of source node are handled. A configuration with side parents of source
-sub-tree with write permission is unsupported (we'd have append several
-backup-top filter like nodes to handle such parents). The test create an
-example of such configuration and checks that a backup is then not allowed
-(blockdev-backup command should fail).
+copy-before-write filter so it can copy all data to the target before it is
+changed.  copy-before-write filter is appended above source node, to achieve
+this thing, so all parents of source node are handled. A configuration with
+side parents of source sub-tree with write permission is unsupported (we'd have
+append several copy-before-write filter like nodes to handle such parents). The
+test create an example of such configuration and checks that a backup is then
+not allowed (blockdev-backup command should fail).
 
 The configuration:
 
@@ -57,11 +57,10 @@ The configuration:
                         │    base     │ ◀──────────── │ other │
                         └─────────────┘               └───────┘
 
-On activation (see .active field of backup-top state in block/backup-top.c),
-backup-top is going to unshare write permission on its source child. Write
-unsharing will be propagated to the "source->base" link and will conflict with
-other node write permission. So permission update will fail and backup job will
-not be started.
+copy-before-write filter wants to unshare write permission on its source child.
+Write unsharing will be propagated to the "source->base" link and will conflict
+with other node write permission. So permission update will fail and backup job
+will not be started.
 
 Note, that the only thing which prevents backup of running on such
 configuration is default permission propagation scheme. It may be altered by
@@ -99,13 +98,9 @@ vm.qmp_log('blockdev-backup', sync='full', device='source', target='target')
 vm.shutdown()
 
 
-print('\n=== backup-top should be gone after job-finalize ===\n')
+print('\n=== copy-before-write filter should be gone after job-finalize ===\n')
 
-# Check that the backup-top node is gone after job-finalize.
-#
-# During finalization, the node becomes inactive and can no longer
-# function.  If it is still present, new parents might be attached, and
-# there would be no meaningful way to handle their I/O requests.
+# Check that the copy-before-write node is gone after job-finalize.
 
 vm = iotests.VM()
 vm.launch()
@@ -131,7 +126,7 @@ vm.qmp_log('blockdev-backup',
 
 vm.event_wait('BLOCK_JOB_PENDING', 5.0)
 
-# The backup-top filter should still be present prior to finalization
+# The copy-before-write filter should still be present prior to finalization
 assert vm.node_info('backup-filter') is not None
 
 vm.qmp_log('job-finalize', id='backup')
diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out
index c6e12b15c5..f2b7219632 100644
--- a/tests/qemu-iotests/283.out
+++ b/tests/qemu-iotests/283.out
@@ -5,9 +5,9 @@
 {"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": "base", "node-name": "other", "take-child-perms": ["write"]}}
 {"return": {}}
 {"execute": "blockdev-backup", "arguments": {"device": "source", "sync": "full", "target": "target"}}
-{"error": {"class": "GenericError", "desc": "Cannot append backup-top filter: Permission conflict on node 'base': permissions 'write' are both required by node 'other' (uses node 'base' as 'image' child) and unshared by node 'source' (uses node 'base' as 'image' child)."}}
+{"error": {"class": "GenericError", "desc": "Cannot append copy-before-write filter: Permission conflict on node 'base': permissions 'write' are both required by node 'other' (uses node 'base' as 'image' child) and unshared by node 'source' (uses node 'base' as 'image' child)."}}
 
-=== backup-top should be gone after job-finalize ===
+=== copy-before-write filter should be gone after job-finalize ===
 
 {"execute": "blockdev-add", "arguments": {"driver": "null-co", "node-name": "source"}}
 {"return": {}}
