[Qemu-devel] [PATCH 2/4] block: image fragmentation statistics for qed

[Dong Xu Wang <wdongxu@linux.vnet.ibm.com>]

From: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>

Add fragmentation statistics for qed file format.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
---
 block/qed.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/block/qed.c b/block/qed.c
index a041d31..eb4dd90 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1444,6 +1444,46 @@ static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     return 0;
 }
 
+static int bdrv_qed_get_fragment(BlockDriverState *bs, BlockFragInfo *bfi)
+{
+    BDRVQEDState *s = bs->opaque;
+    uint32_t cluster_size = s->header.cluster_size;
+    uint64_t table_noffsets = s->header.table_size * cluster_size / sizeof(uint64_t);
+    uint64_t i, j;
+    uint64_t l2_offset;
+    int ret = 0;
+    uint64_t last_offset = 0;
+    uint64_t size = s->header.table_size * cluster_size;
+    uint64_t *table = qemu_blockalign(s->bs, size);
+
+    for (i = 0; i < table_noffsets; i++) {
+        l2_offset = s->l1_table->offsets[i];
+        if (l2_offset == 0) {
+            continue;
+        }
+        ret = bdrv_pread(bs->file, l2_offset, table, size);
+        if (ret < 0) {
+            qemu_vfree(table);
+            return ret;
+        }
+        for (j = 0; j < size/sizeof(uint64_t); j++) {
+            uint64_t *offset = (uint64_t *)(table + j);
+            if (*offset < cluster_size) {
+                continue;
+            }
+            bfi->allocated_clusters++;
+            if (last_offset && (last_offset + cluster_size) != *offset) {
+                bfi->fragmented_clusters++;
+            }
+            last_offset = *offset;
+        }
+    }
+    bfi->total_clusters = (s->header.image_size + s->header.cluster_size - 1) /
+                        s->header.cluster_size;
+    qemu_vfree(table);
+    return ret;
+}
+
 static int bdrv_qed_change_backing_file(BlockDriverState *bs,
                                         const char *backing_file,
                                         const char *backing_fmt)
@@ -1569,6 +1609,7 @@ static BlockDriver bdrv_qed = {
     .bdrv_get_info            = bdrv_qed_get_info,
     .bdrv_change_backing_file = bdrv_qed_change_backing_file,
     .bdrv_check               = bdrv_qed_check,
+    .bdrv_get_fragment        = bdrv_qed_get_fragment,
 };
 
 static void bdrv_qed_init(void)
-- 
1.7.5.4