[PATCH v2 2/3] qemu-img: Fail fast on convert --bitmaps with inconsistent bitmap

[Eric Blake]

Waiting until the end of the convert operation (a potentially
time-consuming task) to finally detect that we can't copy a bitmap is
bad, comparing to failing fast up front.  Furthermore, this prevents
us from leaving a file behind with a bitmap that is not marked as
inconsistent even though it does not have sane contents.

This fixes the problems exposed in the previous patch to the iotest.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 qemu-img.c                                    | 30 +++++++++++++++++--
 tests/qemu-iotests/tests/qemu-img-bitmaps     |  2 --
 tests/qemu-iotests/tests/qemu-img-bitmaps.out | 20 ++-----------
 3 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index 7956a8996512..e84b3c530155 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2101,6 +2101,30 @@ static int convert_do_copy(ImgConvertState *s)
     return s->ret;
 }

+/* Check that bitmaps can be copied, or output an error */
+static int convert_check_bitmaps(BlockDriverState *src)
+{
+    BdrvDirtyBitmap *bm;
+
+    if (!bdrv_supports_persistent_dirty_bitmap(src)) {
+        error_report("Source lacks bitmap support");
+        return -1;
+    }
+    FOR_EACH_DIRTY_BITMAP(src, bm) {
+        const char *name;
+
+        if (!bdrv_dirty_bitmap_get_persistence(bm)) {
+            continue;
+        }
+        name = bdrv_dirty_bitmap_name(bm);
+        if (bdrv_dirty_bitmap_inconsistent(bm)) {
+            error_report("Cannot copy inconsistent bitmap '%s'", name);
+            return -1;
+        }
+    }
+    return 0;
+}
+
 static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
 {
     BdrvDirtyBitmap *bm;
@@ -2127,6 +2151,7 @@ static int convert_copy_bitmaps(BlockDriverState *src, 
BlockDriverState *dst)
                               &err);
         if (err) {
             error_reportf_err(err, "Failed to populate bitmap %s: ", name);
+            qmp_block_dirty_bitmap_remove(dst->node_name, name, NULL);
             return -1;
         }
     }
@@ -2552,9 +2577,8 @@ static int img_convert(int argc, char **argv)
             ret = -1;
             goto out;
         }
-        if (!bdrv_supports_persistent_dirty_bitmap(blk_bs(s.src[0]))) {
-            error_report("Source lacks bitmap support");
-            ret = -1;
+        ret = convert_check_bitmaps(blk_bs(s.src[0]));
+        if (ret < 0) {
             goto out;
         }
     }
diff --git a/tests/qemu-iotests/tests/qemu-img-bitmaps 
b/tests/qemu-iotests/tests/qemu-img-bitmaps
index 2f51651d0ce5..3fde95907515 100755
--- a/tests/qemu-iotests/tests/qemu-img-bitmaps
+++ b/tests/qemu-iotests/tests/qemu-img-bitmaps
@@ -141,8 +141,6 @@ $QEMU_IMG bitmap --remove "$TEST_IMG" b1
 _img_info --format-specific | _filter_irrelevant_img_info
 $QEMU_IMG convert --bitmaps -O qcow2 "$TEST_IMG" "$TEST_IMG.copy" &&
     echo "unexpected success"
-# Bug - even though we failed at conversion, we left a file around with
-# a bitmap marked as not corrupt
 TEST_IMG=$TEST_IMG.copy _img_info --format-specific \
     | _filter_irrelevant_img_info

diff --git a/tests/qemu-iotests/tests/qemu-img-bitmaps.out 
b/tests/qemu-iotests/tests/qemu-img-bitmaps.out
index b762362075d1..546aaa404bba 100644
--- a/tests/qemu-iotests/tests/qemu-img-bitmaps.out
+++ b/tests/qemu-iotests/tests/qemu-img-bitmaps.out
@@ -143,22 +143,6 @@ Format specific information:
             name: b4
             granularity: 65536
     corrupt: false
-qemu-img: Failed to populate bitmap b0: Bitmap 'b0' is inconsistent and cannot 
be used
-Try block-dirty-bitmap-remove to delete this bitmap from disk
-image: TEST_DIR/t.IMGFMT.copy
-file format: IMGFMT
-virtual size: 10 MiB (10485760 bytes)
-cluster_size: 65536
-Format specific information:
-    bitmaps:
-        [0]:
-            flags:
-            name: b0
-            granularity: 65536
-        [1]:
-            flags:
-                [0]: auto
-            name: b4
-            granularity: 65536
-    corrupt: false
+qemu-img: Cannot copy inconsistent bitmap 'b0'
+qemu-img: Could not open 'TEST_DIR/t.IMGFMT.copy': Could not open 
'TEST_DIR/t.IMGFMT.copy': No such file or directory
 *** done
-- 
2.31.1