Changeset 42039 in vbox

Timestamp:

Jul 6, 2012 1:29:33 PM (13 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

78939

Message:

Storage: New return status code when a free block is read

Location:

trunk

Files:

• include/VBox/err.h (modified) (1 diff)
• include/VBox/vd.h (modified) (1 diff)
• src/VBox/Storage/VD.cpp (modified) (1 diff)

trunk/include/VBox/err.h

@@ -1541 +1541 @@
  * This usually indicates that there is a minor corruption in the image meta data. */
 #define VERR_VD_READ_OUT_OF_RANGE                   (-3282)
+/** Block read was marked as free in the image and returned as a zero block. */
+#define VINF_VD_NEW_ZEROED_BLOCK                    3283
 /** @} */
 

trunk/include/VBox/vd.h

@@ -210 +210 @@
  */
 #define VD_OPEN_FLAGS_IGNORE_FLUSH  RT_BIT(8)
+/**
+ * Return VINF_VD_NEW_ZEROED_BLOCK for reads from unallocated blocks.
+ * The caller who uses the flag has to make sure that the read doesn't cross
+ * a block boundary. Because the block size can differ between images reading one
+ * sector at a time is the safest solution.
+ */
+#define VD_OPEN_FLAGS_INFORM_ABOUT_ZERO_BLOCKS RT_BIT(9)
 /** Mask of valid flags. */
-#define VD_OPEN_FLAGS_MASK          (VD_OPEN_FLAGS_NORMAL | VD_OPEN_FLAGS_READONLY | VD_OPEN_FLAGS_HONOR_ZEROES | VD_OPEN_FLAGS_HONOR_SAME | VD_OPEN_FLAGS_INFO | VD_OPEN_FLAGS_ASYNC_IO | VD_OPEN_FLAGS_SHAREABLE | VD_OPEN_FLAGS_SEQUENTIAL | VD_OPEN_FLAGS_DISCARD | VD_OPEN_FLAGS_IGNORE_FLUSH)
+#define VD_OPEN_FLAGS_MASK          (VD_OPEN_FLAGS_NORMAL | VD_OPEN_FLAGS_READONLY | VD_OPEN_FLAGS_HONOR_ZEROES | VD_OPEN_FLAGS_HONOR_SAME | VD_OPEN_FLAGS_INFO | VD_OPEN_FLAGS_ASYNC_IO | VD_OPEN_FLAGS_SHAREABLE | VD_OPEN_FLAGS_SEQUENTIAL | VD_OPEN_FLAGS_DISCARD | VD_OPEN_FLAGS_IGNORE_FLUSH | VD_OPEN_FLAGS_INFORM_ABOUT_ZERO_BLOCKS)
 /** @}*/
 

trunk/src/VBox/Storage/VD.cpp

@@ -990 +990 @@
                 cbBufClear += cbThisRead;
 
-            rc = VINF_SUCCESS;
+            if (pImage->uOpenFlags & VD_OPEN_FLAGS_INFORM_ABOUT_ZERO_BLOCKS)
+                rc = VINF_VD_NEW_ZEROED_BLOCK;
+            else
+                rc = VINF_SUCCESS;
         }
         else if (RT_SUCCESS(rc))