[PATCH] New LDM Driver (Windows Dynamic Disks)

This is a complete rewrite of the LDM driver (support for Windows
Dynamic Disks).  It incorporates Al Viro's recent partition handling
tidy ups.

Details:
  LDM Driver rewritten.  More efficient.  Much smaller memory footprint.

  The old driver was little more than a stopgap.
  The new driver is a complete rewrite
  based on a much better understanding of the database
  based on much more reverse engineering
  more able to spot errors and inconsistancies
  it has a much smaller memory footprint
  no longer considered experimental
  accompanied by brief info: Documentation/ldm.txt

Documentation/00-INDEX

@@ -118,6 +118,8 @@ kernel-parameters.txt
 	- summary listing of command line / boot prompt args for the kernel.
 kmod.txt
 	- info on the kernel module loader/unloader (kerneld replacement).
+ldm.txt
+	- a brief description of LDM (Windows Dynamic Disks).
 locks.txt
 	- info on file locking implementations, flock() vs. fcntl(), etc.
 logo.gif

Documentation/ldm.txt

+
+            LDM - Logical Disk Manager (Dynamic Disks)
+            ------------------------------------------
+
+Overview
+--------
+
+Windows 2000 and XP use a new partitioning scheme.  It is a complete
+replacement for the MSDOS style partitions.  It stores its information in a
+1MiB journalled database at the end of the physical disk.  The size of
+partitions is limited only by disk space.  The maximum number of partitions is
+nearly 2000.
+
+Any partitions created under the LDM are called "Dynamic Disks".  There are no
+longer any primary or extended partitions.  Normal MSDOS style partitions are
+now known as Basic Disks.
+
+If you wish to use Spanned, Striped, Mirrored or RAID 5 Volumes, you must use
+Dynamic Disks.  The journalling allows Windows to make changes to these
+partitions and filesystems without the need to reboot.
+
+Once the LDM driver has divided up the disk, you can use the MD driver to
+assemble any multi-partition volumes, e.g.  Stripes, RAID5.
+
+To prevent legacy applications from repartitioning the disk, the LDM creates a
+dummy MSDOS partition containing one disk-sized partition.
+
+
+Example
+-------
+
+Below we have a 50MiB disk, divided into seven partitions.
+N.B.  The missing 1MiB at the end of the disk is where the LDM database is
+      stored.
+
+  Device | Offset Bytes  Sectors  MiB | Size   Bytes  Sectors  MiB
+  -------+----------------------------+---------------------------
+  hda    |            0        0    0 |     52428800   102400   50
+  hda1   |     51380224   100352   49 |      1048576     2048    1
+  hda2   |        16384       32    0 |      6979584    13632    6
+  hda3   |      6995968    13664    6 |     10485760    20480   10
+  hda4   |     17481728    34144   16 |      4194304     8192    4
+  hda5   |     21676032    42336   20 |      5242880    10240    5
+  hda6   |     26918912    52576   25 |     10485760    20480   10
+  hda7   |     37404672    73056   35 |     13959168    27264   13
+
+The LDM Database may not store the partitions in the order that they appear on
+disk, but the driver will sort them.
+
+When Linux boots, you will see something like:
+
+  hda: 102400 sectors w/32KiB Cache, CHS=50/64/32
+  hda: [LDM] hda1 hda2 hda3 hda4 hda5 hda6 hda7
+
+
+Compiling LDM Support
+---------------------
+
+To enable LDM, choose the following two options: 
+
+  "Advanced partition selection" CONFIG_PARTITION_ADVANCED
+  "Windows Logical Disk Manager (Dynamic Disk) support" CONFIG_LDM_PARTITION
+
+If you believe the driver isn't working as it should, you can enable the extra
+debugging code.  This will produce a LOT of output.  The option is:
+
+  "Windows LDM extra logging" CONFIG_LDM_DEBUG
+
+N.B. The partition code cannot be compiled as a module.
+
+As with all the partition code, if the driver doesn't see signs of its type of
+partition, it will pass control to another driver, so there is no harm in
+enabling it.
+
+If you have Dynamic Disks but don't enable the driver, then all you will see
+is a dummy MSDOS partition filling the whole disk.  You won't be able to mount
+any of the volumes on the disk.
+
+
+Booting
+-------
+
+If you enable LDM support, then lilo is capable of booting from any of the
+discovered partitions.  However, grub does not understand the LDM partitioning
+and cannot boot from a Dynamic Disk.
+
+
+More Documentation
+------------------
+
+There is an Overview of the LDM online together with complete Technical
+Documentation.  It can also be downloaded in html.
+
+  http://linux-ntfs.sourceforge.net/ldm/index.html
+  http://linux-ntfs.sourceforge.net/downloads.html
+
+If you have any LDM questions that aren't answered on the website, email me.
+
+Cheers,
+    FlatCap - Richard Russon
+    ldm@flatcap.org
+

fs/partitions/Config.help

@@ -46,15 +46,14 @@ CONFIG_LDM_PARTITION
 
   Windows 2000 introduced the concept of Dynamic Disks to get around
   the limitations of the PC's partitioning scheme.  The Logical Disk
-  Manager allows the user to repartion a disk and create spanned,
+  Manager allows the user to repartition a disk and create spanned,
   mirrored, striped or RAID volumes, all without the need for
   rebooting.
 
   Normal partitions are now called Basic Disks under Windows 2000 and
   XP.
 
-  Technical documentation to accompany this driver is available from:
-  <http://linux-ntfs.sf.net/ldm/>.
+  For a fuller description read <file:Documentation/ldm.txt>.
 
   If unsure, say N.
 

fs/partitions/Config.in

@@ -25,7 +25,7 @@ if [ "$CONFIG_PARTITION_ADVANCED" = "y" ]; then
       bool '    Solaris (x86) partition table support' CONFIG_SOLARIS_X86_PARTITION
       bool '    Unixware slices support' CONFIG_UNIXWARE_DISKLABEL
    fi
-   dep_bool '  Windows Logical Disk Manager (Dynamic Disk) support (EXPERIMENTAL)' CONFIG_LDM_PARTITION $CONFIG_EXPERIMENTAL
+   dep_bool '  Windows Logical Disk Manager (Dynamic Disk) support' CONFIG_LDM_PARTITION
    if [ "$CONFIG_LDM_PARTITION" = "y" ]; then
       bool '    Windows LDM extra logging' CONFIG_LDM_DEBUG
    fi

fs/partitions/ldm.h

-#ifndef _FS_PT_LDM_H_
-#define _FS_PT_LDM_H_
-/*
+/**
  * ldm - Part of the Linux-NTFS project.
  *
- * Copyright (C) 2001 Richard Russon <ldm@flatcap.org>
- * Copyright (C) 2001 Anton Altaparmakov
+ * Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
+ * Copyright (C) 2001      Anton Altaparmakov <aia21@cantab.net>
+ * Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
  *
  * Documentation is available at http://linux-ntfs.sf.net/ldm
  *
@@ -23,16 +22,18 @@
  * in the file COPYING); if not, write to the Free Software Foundation,
  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+
+#ifndef _FS_PT_LDM_H_
+#define _FS_PT_LDM_H_
+
 #include <linux/types.h>
+#include <linux/list.h>
+#include <linux/genhd.h>
+#include <linux/fs.h>
 #include <asm/unaligned.h>
 #include <asm/byteorder.h>
-#include <linux/genhd.h>
 
-/* Borrowed from kernel.h. */
-#define LDM_PREFIX	"LDM: "	   /* Prefix our error messages with this. */
-#define LDM_CRIT	KERN_CRIT	LDM_PREFIX /* critical conditions */
-#define LDM_ERR		KERN_ERR	LDM_PREFIX /* error conditions */
-#define LDM_DEBUG	KERN_DEBUG	LDM_PREFIX /* debug-level messages */
+struct parsed_partitions;
 
 /* Magic numbers in CPU format. */
 #define MAGIC_VMDB	0x564D4442		/* VMDB */
@@ -41,41 +42,58 @@
 #define MAGIC_TOCBLOCK	0x544F43424C4F434B	/* TOCBLOCK */
 
 /* The defined vblk types. */
-#define VBLK_COMP		0x32		/* Component */
-#define VBLK_PART		0x33		/* Partition */
-#define VBLK_DSK1		0x34		/* Disk */
-#define VBLK_DSK2		0x44		/* Disk */
-#define VBLK_DGR1		0x35		/* Disk Group */
-#define VBLK_DGR2		0x45		/* Disk Group */
-#define VBLK_VOLU		0x51		/* Volume */
+#define VBLK_VOL5		0x51		/* Volume,     version 5 */
+#define VBLK_CMP3		0x32		/* Component,  version 3 */
+#define VBLK_PRT3		0x33		/* Partition,  version 3 */
+#define VBLK_DSK3		0x34		/* Disk,       version 3 */
+#define VBLK_DSK4		0x44		/* Disk,       version 4 */
+#define VBLK_DGR3		0x35		/* Disk Group, version 3 */
+#define VBLK_DGR4		0x45		/* Disk Group, version 4 */
+
+/* vblk flags indicating extra information will be present */
+#define	VBLK_FLAG_COMP_STRIPE	0x10
+#define	VBLK_FLAG_PART_INDEX	0x08
+#define	VBLK_FLAG_DGR3_IDS	0x08
+#define	VBLK_FLAG_DGR4_IDS	0x08
+#define	VBLK_FLAG_VOLU_ID1	0x08
+#define	VBLK_FLAG_VOLU_ID2	0x20
+#define	VBLK_FLAG_VOLU_SIZE	0x80
+#define	VBLK_FLAG_VOLU_DRIVE	0x02
+
+/* size of a vblk's static parts */
+#define VBLK_SIZE_HEAD		16
+#define VBLK_SIZE_CMP3		22		/* Name and version */
+#define VBLK_SIZE_DGR3		12
+#define VBLK_SIZE_DGR4		44
+#define VBLK_SIZE_DSK3		12
+#define VBLK_SIZE_DSK4		45
+#define VBLK_SIZE_PRT3		28
+#define VBLK_SIZE_VOL5		59
+
+/* component types */
+#define COMP_STRIPE		0x01		/* Stripe-set */
+#define COMP_BASIC		0x02		/* Basic disk */
+#define COMP_RAID		0x03		/* Raid-set */
 
 /* Other constants. */
-#define LDM_BLOCKSIZE		1024		/* Size of block in bytes. */
 #define LDM_DB_SIZE		2048		/* Size in sectors (= 1MiB). */
-#define LDM_FIRST_PART_OFFSET	4		/* Add this to first_part_minor
-						   to get to the first data
-						   partition device minor. */
 
-#define OFF_PRIVHEAD1		3		/* Offset of the first privhead
+#define OFF_PRIV1		6		/* Offset of the first privhead
 						   relative to the start of the
-						   device in units of
-						   LDM_BLOCKSIZE. */
+						   device in sectors */
 
-/* Offsets to structures within the LDM Database in units of LDM_BLOCKSIZE. */
-#define OFF_PRIVHEAD2		928		/* Backup private headers. */
-#define OFF_PRIVHEAD3		1023
+/* Offsets to structures within the LDM Database in sectors. */
+#define OFF_PRIV2		1856		/* Backup private headers. */
+#define OFF_PRIV3		2047
 
-#define OFF_TOCBLOCK1		0		/* Tables of contents. */
-#define OFF_TOCBLOCK2		1
-#define OFF_TOCBLOCK3		1022
-#define OFF_TOCBLOCK4		1023
+#define OFF_TOCB1		1		/* Tables of contents. */
+#define OFF_TOCB2		2
+#define OFF_TOCB3		2045
+#define OFF_TOCB4		2046
 
-#define OFF_VMDB		8		/* List of partitions. */
-#define OFF_VBLK		9
+#define OFF_VMDB		17		/* List of partitions. */
 
-#define WIN2K_DYNAMIC_PARTITION		0x42	/* Formerly SFS (Landis). */
-#define WIN2K_EXTENDED_PARTITION	0x05	/* A standard extended
-						   partition. */
+#define WIN2K_DYNAMIC_PARTITION	0x42		/* Formerly SFS (Landis). */
 
 #define TOC_BITMAP1		"config"	/* Names of the two defined */
 #define TOC_BITMAP2		"log"		/* bitmaps in the TOCBLOCK. */
@@ -85,49 +103,42 @@
 #define BE32(x)			((u32)be32_to_cpu(get_unaligned((u32*)(x))))
 #define BE64(x)			((u64)be64_to_cpu(get_unaligned((u64*)(x))))
 
-/* Borrowed from msdos.c. */
+/* Borrowed from msdos.c */
 #define SYS_IND(p)		(get_unaligned(&(p)->sys_ind))
-#define NR_SECTS(p)		({ __typeof__((p)->nr_sects) __a =	\
-					get_unaligned(&(p)->nr_sects);	\
-					le32_to_cpu(__a);		\
-				})
 
-#define START_SECT(p)		({ __typeof__((p)->start_sect) __a =	\
-					get_unaligned(&(p)->start_sect);\
-					le32_to_cpu(__a);		\
-				})
+struct frag {				/* VBLK Fragment handling */
+	struct list_head list;
+	u32		group;
+	u8		num;		/* Total number of records */
+	u8		rec;		/* This is record number n */
+	u8		map;		/* Which portions are in use */
+	u8		data[0];
+};
 
 /* In memory LDM database structures. */
 
-#define DISK_ID_SIZE		64	/* Size in bytes. */
-
-struct ldmdisk {
-	u64	obj_id;
-	u8	disk_id[DISK_ID_SIZE];
-};
+#define GUID_SIZE		16
 
-struct privhead	{			/* Offsets and sizes are in sectors. */
+struct privhead {			/* Offsets and sizes are in sectors. */
 	u16	ver_major;
 	u16	ver_minor;
 	u64	logical_disk_start;
 	u64	logical_disk_size;
 	u64	config_start;
 	u64	config_size;
-	u8	disk_id[DISK_ID_SIZE];
+	u8	disk_id[GUID_SIZE];
 };
 
 struct tocblock {			/* We have exactly two bitmaps. */
 	u8	bitmap1_name[16];
 	u64	bitmap1_start;
 	u64	bitmap1_size;
-	/*u64	bitmap1_flags;*/
 	u8	bitmap2_name[16];
 	u64	bitmap2_start;
 	u64	bitmap2_size;
-	/*u64	bitmap2_flags;*/
 };
 
-struct vmdb {
+struct vmdb {				/* VMDB: The database header */
 	u16	ver_major;
 	u16	ver_minor;
 	u32	vblk_size;
@@ -135,22 +146,75 @@ struct vmdb {
 	u32	last_vblk_seq;
 };
 
-struct vblk {
+struct vblk_comp {			/* VBLK Component */
+	u8	state[16];
+	u64	parent_id;
+	u8	type;
+	u8	children;
+	u16	chunksize;
+};
+
+struct vblk_dgrp {			/* VBLK Disk Group */
+	u8	disk_id[64];
+};
+
+struct vblk_disk {			/* VBLK Disk */
+	u8	disk_id[GUID_SIZE];
+	u8	alt_name[128];
+};
+
+struct vblk_part {			/* VBLK Partition */
+	u64	start;
+	u64	size;			/* start, size and vol_off in sectors */
+	u64	volume_offset;
+	u64	parent_id;
+	u64	disk_id;
+	u8	partnum;
+};
+
+struct vblk_volu {			/* VBLK Volume */
+	u8	volume_type[16];
+	u8	volume_state[16];
+	u8	guid[16];
+	u8	drive_hint[4];
+	u64	size;
+	u8	partition_type;
+};
+
+struct vblk_head {			/* VBLK standard header */
+	u32 group;
+	u16 rec;
+	u16 nrec;
+};
+
+struct vblk {				/* Generalised VBLK */
 	u8	name[64];
-	u8	vblk_type;
 	u64	obj_id;
-	u64	disk_id;
-	u64	start_sector;
-	u64	num_sectors;
+	u32	sequence;
+	u8	flags;
+	u8	type;
+	union {
+		struct vblk_comp comp;
+		struct vblk_dgrp dgrp;
+		struct vblk_disk disk;
+		struct vblk_part part;
+		struct vblk_volu volu;
+	} vblk;
+	struct list_head list;
 };
 
-struct ldm_part {
-	struct list_head part_list;
-	unsigned long start;
-	unsigned long size;
+struct ldmdb {				/* Cache of the database */
+	struct privhead ph;
+	struct tocblock toc;
+	struct vmdb     vm;
+	struct list_head v_dgrp;
+	struct list_head v_disk;
+	struct list_head v_volu;
+	struct list_head v_comp;
+	struct list_head v_part;
 };
 
-int ldm_partition(struct parsed_partitions *state, struct block_device *bdev);
+int ldm_partition (struct parsed_partitions *state, struct block_device *bdev);
 
 #endif /* _FS_PT_LDM_H_ */