[ros-diffs] [fireball] 31221: Filip Navara <xnavara at volny dot cz> - Remove unused code from HvGetCellSize(). - Fix situation, when a new cell is allocated with a too small size, resulting in an empty free cell (a cell has to be able to store at least one HCELL_INDEX), then the free list code overrides the next cell after the empty one. - Reenable commented out assert in HvpRemoveFree(), since now it works as expected.

Author: fireball
Date: Sat Dec 15 02:17:43 2007
New Revision: 31221

URL: http://svn.reactos.org/svn/reactos?rev=31221&view=rev
Log:
Filip Navara <xnavara at volny dot cz>
- Remove unused code from HvGetCellSize().
- Fix situation, when a new cell is allocated with a too small size, resulting in an empty free cell (a cell has to be able to store at least one HCELL_INDEX), then the free list code overrides the next cell after the empty one.
- Reenable commented out assert in HvpRemoveFree(), since now it works as expected.

Modified:
    trunk/reactos/lib/cmlib/hivecell.c

Modified: trunk/reactos/lib/cmlib/hivecell.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/lib/cmlib/hivecell.c?rev=31...
==============================================================================
--- trunk/reactos/lib/cmlib/hivecell.c (original)
+++ trunk/reactos/lib/cmlib/hivecell.c Sat Dec 15 02:17:43 2007
@@ -103,7 +103,6 @@
    HCELL_INDEX CellIndex,
    BOOLEAN HoldingLock)
 {
-   LONG CellSize;
    ULONG CellBlock;
    ULONG CellLastBlock;

@@ -117,10 +116,6 @@

CellBlock = (CellIndex & HCELL_BLOCK_MASK) >> HCELL_BLOCK_SHIFT;
    CellLastBlock = ((CellIndex + HV_BLOCK_SIZE - 1) & HCELL_BLOCK_MASK) >> HCELL_BLOCK_SHIFT;
-
-   CellSize = HvpGetCellFullSize(RegistryHive, HvGetCell(RegistryHive, CellIndex));
-   if (CellSize < 0)
-      CellSize = -CellSize;

RtlSetBits(&RegistryHive->DirtyVector,
               CellBlock, CellLastBlock - CellBlock);
@@ -229,7 +224,7 @@
       pFreeCellOffset = FreeCellData;
    }

-   //ASSERT(FALSE);
+   ASSERT(FALSE);
 }

static HCELL_INDEX CMAPI
@@ -349,8 +344,13 @@
    FreeCell = HvpGetCellHeader(RegistryHive, FreeCellOffset);

/* Split the block in two parts */
-   /* FIXME: There is some minimal cell size that we must respect. */
-   if ((ULONG)FreeCell->Size > Size + sizeof(HCELL_INDEX))
+
+   /* The free block that is created has to be at least
+      sizeof(HCELL) + sizeof(HCELL_INDEX) big, so that free
+      cell list code can work. Moreover we round cell sizes
+      to 16 bytes, so creating a smaller block would result in
+      a cell that would never be allocated. */
+   if ((ULONG)FreeCell->Size > Size + 16)
    {
       NewCell = (PHCELL)((ULONG_PTR)FreeCell + Size);
       NewCell->Size = FreeCell->Size - Size;