From 709f197b2ddcfdb0a0a5f486f7ad96e23bdd51b7 Mon Sep 17 00:00:00 2001
From: Uri Lublin <uril@redhat.com>
Date: Mon, 30 Mar 2009 23:15:44 +0300
Subject: [PATCH 03/12] Revert "qcow2 format: keep 'num_free_bytes', and show it upon 'info blockstats' (Uri Lublin)"

This reverts commit 69f6850da20d243515479add9ba182075c317b55.

Was not accepted upstream. Using an alternative solution with
watermark and asynchronous notification.

Signed-off-by: Uri Lublin <uril@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Bugzilla: 489964
RH-Upstream-status: not-applicable
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Dor Laor <dlaor@redhat.com>
---
 qemu/block-qcow2.c |   36 ++++++++----------------------------
 qemu/block.c       |    5 ++---
 qemu/block.h       |    1 -
 3 files changed, 10 insertions(+), 32 deletions(-)

diff --git a/qemu/block-qcow2.c b/qemu/block-qcow2.c
index b58203c..9175c9d 100644
--- a/qemu/block-qcow2.c
+++ b/qemu/block-qcow2.c
@@ -145,7 +145,6 @@ typedef struct BDRVQcowState {
     AES_CBC_CIPHER aes_decrypt_cipher;
 
     int64_t highest_alloc; /* highest cluester allocated (in clusters) */
-    int64_t nc_free;       /* num of free clusters below highest_alloc */
 
     uint64_t snapshots_offset;
     int snapshots_size;
@@ -174,7 +173,7 @@ static void free_clusters(BlockDriverState *bs,
 #ifdef DEBUG_ALLOC
 static void check_refcounts(BlockDriverState *bs);
 #endif
-static void scan_refcount(BlockDriverState *bs, int64_t *high, int64_t *free);
+static void scan_refcount(BlockDriverState *bs, int64_t *high);
 
 
 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
@@ -284,7 +283,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
     if (refcount_init(bs) < 0)
         goto fail;
 
-    scan_refcount(bs, &s->highest_alloc, &s->nc_free);
+    scan_refcount(bs, &s->highest_alloc);
 
     /* read the backing file name */
     if (header.backing_file_offset != 0) {
@@ -1684,7 +1683,6 @@ static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
         (s->cluster_bits + s->l2_bits);
     bdi->highest_alloc = s->highest_alloc << s->cluster_bits;
-    bdi->num_free_bytes = s->nc_free  << s->cluster_bits;
     return 0;
 }
 
@@ -2219,35 +2217,25 @@ static int load_refcount_block(BlockDriverState *bs,
     return 0;
 }
 
-static void scan_refcount(BlockDriverState *bs, int64_t *high, int64_t *free)
+static void scan_refcount(BlockDriverState *bs, int64_t *high)
 {
     BDRVQcowState *s = bs->opaque;
-    int64_t refcnt_index, cluster_index, cluster_end, h = 0, f = 0;
-    int64_t tail = 0; /* do not count last consecutive free entries */
+    int64_t refcnt_index, cluster_index, cluster_end, h = 0;
 
     for (refcnt_index=0; refcnt_index < s->refcount_table_size; refcnt_index++){
         if (s->refcount_table[refcnt_index] == 0) {
-            f += 1 << (s->cluster_bits - REFCOUNT_SHIFT);
-            tail += 1 << (s->cluster_bits - REFCOUNT_SHIFT);
             continue;
         }
         cluster_index = refcnt_index << (s->cluster_bits - REFCOUNT_SHIFT);
         cluster_end = (refcnt_index + 1) << (s->cluster_bits - REFCOUNT_SHIFT);
         for ( ; cluster_index < cluster_end; cluster_index++) {
-            if (get_refcount(bs, cluster_index) == 0) {
-                f++;
-                tail++;
-            }
-            else {
+            if (get_refcount(bs, cluster_index) == 0)
+                /* do nothing -- reserved for free counting */;
+            else
                 h = cluster_index;
-                tail = 0;
-            }
         }
     }
 
-    f -= tail;
-    if (free)
-        *free = f;
     if (high)
         *high = (h+1);
 }
@@ -2293,10 +2281,8 @@ retry:
             (s->free_cluster_index - nb_clusters) << s->cluster_bits);
 #endif
 
-    if (s->highest_alloc < s->free_cluster_index) {
-        s->nc_free += (s->free_cluster_index - s->highest_alloc);
+    if (s->highest_alloc < s->free_cluster_index)
         s->highest_alloc = s->free_cluster_index;
-    }
 
     return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
 }
@@ -2473,12 +2459,6 @@ static int update_cluster_refcount(BlockDriverState *bs,
     block_index = cluster_index &
         ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
     refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
-
-    if (refcount == 1 && addend == -1)
-        s->nc_free += 1;
-    else if (refcount == 0 && addend == 1)
-        s->nc_free -= 1;
-
     refcount += addend;
     if (refcount < 0 || refcount > 0xffff)
         return -EINVAL;
diff --git a/qemu/block.c b/qemu/block.c
index 05cd742..7f24866 100644
--- a/qemu/block.c
+++ b/qemu/block.c
@@ -1177,9 +1177,8 @@ void bdrv_info_stats (void)
 		     bs->rd_bytes, bs->wr_bytes,
 		     bs->rd_ops, bs->wr_ops);
         if (bdrv_get_info(bs, &bdi) == 0)
-            term_printf(" high=%" PRId64
-                        " bytes_free=%" PRId64,
-                        bdi.highest_alloc, bdi.num_free_bytes);
+            term_printf(" high=%" PRIu64,
+                        bdi.highest_alloc);
         term_printf("\n");
     }
 }
diff --git a/qemu/block.h b/qemu/block.h
index 1390693..403065b 100644
--- a/qemu/block.h
+++ b/qemu/block.h
@@ -26,7 +26,6 @@ typedef struct BlockDriverInfo {
     /* offset at which the VM state can be saved (0 if not possible) */
     int64_t vm_state_offset;
     int64_t highest_alloc; /* highest allocated block offset (in bytes) */
-    int64_t num_free_bytes; /* below highest_alloc  */
 } BlockDriverInfo;
 
 typedef struct QEMUSnapshotInfo {
-- 
1.6.1