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Message-Id: <20101108190918.072277471@redhat.com>
Date: Mon, 08 Nov 2010 17:02:54 -0200
From: Marcelo Tosatti <mtosatti@redhat.com>
References: <20101108190253.560821111@redhat.com>
Content-Disposition: inline; filename=01-block-dirty-log-shift
Subject: [Qemu-devel] [patch 1/3] block: fix shift in dirty bitmap
	calculation
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To: Liran Schour <LIRANS@il.ibm.com>, Kevin Wolf <kwolf@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>, qemu-devel@nongnu.org

Otherwise upper 32 bits of bitmap entries are not correctly calculated.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: qemu-kvm/block.c
===================================================================
--- qemu-kvm.orig/block.c
+++ qemu-kvm/block.c
@@ -930,14 +930,14 @@ static void set_dirty_bitmap(BlockDriver
         bit = start % (sizeof(unsigned long) * 8);
         val = bs->dirty_bitmap[idx];
         if (dirty) {
-            if (!(val & (1 << bit))) {
+            if (!(val & (1UL << bit))) {
                 bs->dirty_count++;
-                val |= 1 << bit;
+                val |= 1UL << bit;
             }
         } else {
-            if (val & (1 << bit)) {
+            if (val & (1UL << bit)) {
                 bs->dirty_count--;
-                val &= ~(1 << bit);
+                val &= ~(1UL << bit);
             }
         }
         bs->dirty_bitmap[idx] = val;
@@ -2672,8 +2672,8 @@ int bdrv_get_dirty(BlockDriverState *bs,
 
     if (bs->dirty_bitmap &&
         (sector << BDRV_SECTOR_BITS) < bdrv_getlength(bs)) {
-        return bs->dirty_bitmap[chunk / (sizeof(unsigned long) * 8)] &
-            (1 << (chunk % (sizeof(unsigned long) * 8)));
+        return !!(bs->dirty_bitmap[chunk / (sizeof(unsigned long) * 8)] &
+            (1UL << (chunk % (sizeof(unsigned long) * 8))));
     } else {
         return 0;
     }