[Qemu-devel] [patch 5/5][v2] Try to aggregate free clusters and freed clusters

[Laurent Vivier]

In free_used_clusters(), try to aggregate free clusters and freed clusters.

Signed-off-by: Laurent Vivier <address@hidden>
---
 block-qcow2.c |   61 ++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 36 insertions(+), 25 deletions(-)

Index: qemu/block-qcow2.c
===================================================================
--- qemu.orig/block-qcow2.c     2008-07-29 15:22:28.000000000 +0200
+++ qemu/block-qcow2.c  2008-07-29 15:22:30.000000000 +0200
@@ -649,6 +649,8 @@ static uint64_t free_used_clusters(Block
     BDRVQcowState *s = bs->opaque;
     int l1_index, ret;
     uint64_t cluster_offset;
+    int i, j, do_loop;
+    uint64_t current;
 
     l1_index = offset >> (s->l2_bits + s->cluster_bits);
     if (l1_index >= s->l1_size) {
@@ -676,17 +678,6 @@ static uint64_t free_used_clusters(Block
     if (nb_clusters && *nb_clusters > s->l2_size - (*l2_index))
             *nb_clusters = s->l2_size - (*l2_index);
 
-    if (!cluster_offset) {
-        if (nb_clusters) {
-            int i = 1;
-            while (i < *nb_clusters && (*l2_table)[(*l2_index) + i] == 0) {
-                i++;
-            }
-            *nb_clusters = i;
-        }
-        return 0;
-    }
-
     if (cluster_offset & QCOW_OFLAG_COPIED) {
         if (nb_clusters) {
             int i = 1;
@@ -702,8 +693,6 @@ static uint64_t free_used_clusters(Block
         return cluster_offset;
     }
 
-    /* free the cluster */
-
     if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
         int nb_csectors;
         nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
@@ -714,22 +703,44 @@ static uint64_t free_used_clusters(Block
         return 0;
     }
 
-    if (nb_clusters) {
-        int i = 1;
-        uint64_t current;
-        while (i < *nb_clusters) {
-            current = be64_to_cpu((*l2_table)[(*l2_index) + i]);
-            if (cluster_offset + (i << s->cluster_bits) != current)
-                break;
-            i++;
-        }
-        *nb_clusters = i;
-        free_clusters(bs, cluster_offset, i << s->cluster_bits);
+    if (!nb_clusters) {
+        if (cluster_offset)
+            free_clusters(bs, cluster_offset, s->cluster_size);
         return 0;
     }
 
-    free_clusters(bs, cluster_offset, s->cluster_size);
+    i = 0;
+    do_loop = 1;
+    while (i < *nb_clusters && do_loop) {
+        i++;
+        if (!cluster_offset) {
+            while (i < *nb_clusters) {
+                cluster_offset = (*l2_table)[(*l2_index) + i];
+                if (cluster_offset)
+                    break;
+                i++;
+            }
+            if ((cluster_offset & QCOW_OFLAG_COPIED) ||
+                (cluster_offset & QCOW_OFLAG_COMPRESSED))
+                do_loop = 0;
+        } else {
+            j = 1;
+            current = 0;
+            while (i < *nb_clusters) {
+                current = be64_to_cpu((*l2_table)[(*l2_index) + i]);
+                if (cluster_offset + (j << s->cluster_bits) != current)
+                    break;
+                i++;
+                j++;
+            }
+            free_clusters(bs, cluster_offset, j << s->cluster_bits);
+            cluster_offset = current;
+            if (current)
+                do_loop = 0;
+        }
+    }
 
+    *nb_clusters = i;
     return 0;
 }
 

--