Re: [PATCH v4 16/21] parallels: Truncate images on the last used cluster

[Denis V. Lunev]

On 12/28/23 11:12, Alexander Ivanov wrote:

On an image closing there can be unused clusters in the end of the image.
Truncate these clusters and update data_end field.

Signed-off-by: Alexander Ivanov 
---
  block/parallels.c | 20 ++--
  1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index fb7bc5e555..136865d53e 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -1454,6 +1454,23 @@ fail:
  return ret;
  }
  
+static int GRAPH_RDLOCK parallels_truncate_unused_clusters(BlockDriverState *bs)

+{
+BDRVParallelsState *s = bs->opaque;
+uint64_t end_off = 0;
+if (s->used_bmap_size > 0) {
+end_off = find_last_bit(s->used_bmap, s->used_bmap_size);
+if (end_off == s->used_bmap_size) {
+end_off = 0;
+} else {
+end_off = (end_off + 1) * s->cluster_size;
+}
+}
+end_off += s->data_start * BDRV_SECTOR_SIZE;
+s->data_end = end_off / BDRV_SECTOR_SIZE;
+return bdrv_truncate(bs->file, end_off, true, PREALLOC_MODE_OFF, 0, NULL);
+}
+
  static int GRAPH_RDLOCK parallels_inactivate(BlockDriverState *bs)
  {
  BDRVParallelsState *s = bs->opaque;
@@ -1471,8 +1488,7 @@ static int GRAPH_RDLOCK 
parallels_inactivate(BlockDriverState *bs)
  parallels_update_header(bs);
  
  /* errors are ignored, so we might as well pass exact=true */

-ret = bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS,
-true, PREALLOC_MODE_OFF, 0, NULL);
+ret = parallels_truncate_unused_clusters(bs);
  if (ret < 0) {
  error_report("Failed to truncate image: %s", strerror(-ret));
  }

Reviewed-by: Denis V. Lunev 

[PATCH v4 16/21] parallels: Truncate images on the last used cluster

[Alexander Ivanov]

On an image closing there can be unused clusters in the end of the image.
Truncate these clusters and update data_end field.

Signed-off-by: Alexander Ivanov 
---
 block/parallels.c | 20 ++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/block/parallels.c b/block/parallels.c
index fb7bc5e555..136865d53e 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -1454,6 +1454,23 @@ fail:
 return ret;
 }
 
+static int GRAPH_RDLOCK parallels_truncate_unused_clusters(BlockDriverState 
*bs)
+{
+BDRVParallelsState *s = bs->opaque;
+uint64_t end_off = 0;
+if (s->used_bmap_size > 0) {
+end_off = find_last_bit(s->used_bmap, s->used_bmap_size);
+if (end_off == s->used_bmap_size) {
+end_off = 0;
+} else {
+end_off = (end_off + 1) * s->cluster_size;
+}
+}
+end_off += s->data_start * BDRV_SECTOR_SIZE;
+s->data_end = end_off / BDRV_SECTOR_SIZE;
+return bdrv_truncate(bs->file, end_off, true, PREALLOC_MODE_OFF, 0, NULL);
+}
+
 static int GRAPH_RDLOCK parallels_inactivate(BlockDriverState *bs)
 {
 BDRVParallelsState *s = bs->opaque;
@@ -1471,8 +1488,7 @@ static int GRAPH_RDLOCK 
parallels_inactivate(BlockDriverState *bs)
 parallels_update_header(bs);
 
 /* errors are ignored, so we might as well pass exact=true */
-ret = bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS,
-true, PREALLOC_MODE_OFF, 0, NULL);
+ret = parallels_truncate_unused_clusters(bs);
 if (ret < 0) {
 error_report("Failed to truncate image: %s", strerror(-ret));
 }
-- 
2.40.1