Changeset 802

Timestamp:

07/14/08 20:34:56 (2 months ago)

Author:

mwhitworth

Message:

Add comments.

Files:

• Whitix/branches/fs/fs/ext3/balloc.c (modified) (4 diffs)

Whitix/branches/fs/fs/ext3/balloc.c

@@ +1 @@
+/*  This file is part of Whitix.
+ *
+ *  Whitix is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Whitix is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with Whitix; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
 #include <bitmap.h>
 
 #include "ext3.h"
+
+/*******************************************************************************
+ *
+ * FUNCTION:    Ext3GetGroupDesc
+ *
+ * DESCRIPTION: Get the on-disk group descriptor with index 'groupNo'.
+ *
+ * PARAMETERS:  superBlock      - superblock of the filesystem that contains the
+ *                                                        descriptors.
+ *                              groupNo         - index of the group.
+ *                              buffer          - return the buffer containing the group on-disk,
+ *                                                        in case the calling function wants to update the
+ *                                                        buffer and call JournalDirtyMetadata. (OPTIONAL)
+ *
+ * RETURNS:     A pointer to the group descriptor in the buffer.
+ *
+ ******************************************************************************/
 
 struct Ext3GroupDesc* Ext3GetGroupDesc(struct VfsSuperBlock* superBlock, DWORD groupNo,
@@ -8 +43 @@
         struct Ext3GroupDesc* descP;
         DWORD groupDesc, desc;
-        
+        struct Ext3SbInfo* sbInfo=EXT3_SUPERINFO(superBlock);
+        
+        /* 
+         * The group descriptors are located after the superblock on disk, and are
+         * read in when the superblock is mounted.
+         */
+         
+        if (groupNo >= sbInfo->groupCount)
+                return NULL;
+        
+        /* Sector index of the group */
         groupDesc=groupNo/DESCS_PER_BLOCK(superBlock);
+        
+        /* Offset within the group */
         desc = groupNo % DESCS_PER_BLOCK(superBlock);
         
-        descP=(struct Ext3GroupDesc*)EXT3_SUPERINFO(superBlock)->descs[groupDesc]->data;
+        descP=(struct Ext3GroupDesc*)(EXT3_SUPERINFO(superBlock)->descs[groupDesc]->data);
         
         if (buffer)
@@ -19 +66 @@
         return descP+desc;
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    Ext3BlockLoadBitmap
+ *
+ * DESCRIPTION: Load the block bitmap pointed to by the group descriptor at index
+ *                              blockGroup.
+ *
+ * PARAMETERS:  superBlock      - superblock of the filesystem that contains the
+ *                                                        descriptor.
+ *                              groupNo         - index of the group.
+ *
+ * RETURNS:     A buffer pointer to the block bitmap.
+ *
+ ******************************************************************************/
 
 struct Buffer* Ext3BlockLoadBitmap(struct VfsSuperBlock* superBlock, int blockGroup)
@@ -222 +284 @@
         offset=blockNo % sbInfo->blocksPerGrp;
         
-        KePrint("group = %u\n", group);
+        if (group >= sbInfo->groupCount)
+        {
+                KePrint("Ext3BlockFree: blockNo = %d, %u %u", blockNo, group, sbInfo->groupCount);
+                return -EIO;
+        }
         
         desc=Ext3GetGroupDesc(superBlock, group, &groupBuffer);