[USETUP] Additions for the PartList code.

- Document more some of the fields in the PARTENTRY, DISKETNRY and PARTLIST structures;
- Remove the redundant members "SystemDisk", "OriginalSystemDisk" and "TempDisk" in PARTLIST as these can be consistently deduced from the corresponding (Original)(System)(Temp)Partition members
  (note that we however keep "CurrentDisk" alongside "CurrentPartition", see the comment in the code why we do it so).
- Adjust the rest of the code to take the removal of the redundant members into account. The 2nd parameter of GetNextUnformattedPartition() and GetNextUncheckedPartition() is now really optional.
- Introduce a SetPartitionType() helper to simplify the code that sets the partition type, which also automatically adjusts other internal variables of said partition in accordance.
- "Mounted" logical drives can have assigned letters too, registered in \DosDevices\.

svn path=/branches/setup_improvements/; revision=74532

base/setup/usetup/partlist.c

@@ -700,10 +700,28 @@ AddPartitionToDisk(
     if (IsContainerPartition(PartEntry->PartitionType))
     {
         PartEntry->FormatState = Unformatted;
+        PartEntry->FileSystem  = NULL;
 
         if (LogicalPartition == FALSE && DiskEntry->ExtendedPartition == NULL)
             DiskEntry->ExtendedPartition = PartEntry;
     }
+#if 0
+    else if (IsRecognizedPartition(PartEntry->PartitionType))
+    {
+        // FIXME FIXME! We should completely rework how we get this 'FileSystemList' available...
+        PartEntry->FileSystem = GetFileSystem(FileSystemList, PartEntry);
+        if (!PartEntry->FileSystem)
+            PartEntry->FormatState = Preformatted;
+        else
+            PartEntry->FormatState = Unformatted;
+        // PartEntry->FormatState = UnknownFormat;
+    }
+    else
+    {
+        /* Unknown partition, so unknown partition format (may or may not be actually formatted) */
+        PartEntry->FormatState = UnknownFormat;
+    }
+#endif
     else if ((PartEntry->PartitionType == PARTITION_FAT_12) ||
              (PartEntry->PartitionType == PARTITION_FAT_16) ||
              (PartEntry->PartitionType == PARTITION_HUGE) ||
@@ -806,6 +824,7 @@ ScanForUnpartitionedDiskSpace(
         DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
         NewPartEntry->FormatState = Unformatted;
+        NewPartEntry->FileSystem  = NULL;
 
         InsertTailList(&DiskEntry->PrimaryPartListHead,
                        &NewPartEntry->ListEntry);
@@ -852,6 +871,7 @@ ScanForUnpartitionedDiskSpace(
                 DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
                 NewPartEntry->FormatState = Unformatted;
+                NewPartEntry->FileSystem  = NULL;
 
                 /* Insert the table into the list */
                 InsertTailList(&PartEntry->ListEntry,
@@ -892,6 +912,7 @@ ScanForUnpartitionedDiskSpace(
             DPRINT("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
             NewPartEntry->FormatState = Unformatted;
+            NewPartEntry->FileSystem  = NULL;
 
             /* Append the table to the list */
             InsertTailList(&DiskEntry->PrimaryPartListHead,
@@ -924,6 +945,7 @@ ScanForUnpartitionedDiskSpace(
             DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
             NewPartEntry->FormatState = Unformatted;
+            NewPartEntry->FileSystem  = NULL;
 
             InsertTailList(&DiskEntry->LogicalPartListHead,
                            &NewPartEntry->ListEntry);
@@ -971,6 +993,7 @@ ScanForUnpartitionedDiskSpace(
                     DPRINT("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
                     NewPartEntry->FormatState = Unformatted;
+                    NewPartEntry->FileSystem  = NULL;
 
                     /* Insert the table into the list */
                     InsertTailList(&PartEntry->ListEntry,
@@ -1012,6 +1035,7 @@ ScanForUnpartitionedDiskSpace(
                 DPRINT("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
                 NewPartEntry->FormatState = Unformatted;
+                NewPartEntry->FileSystem  = NULL;
 
                 /* Append the table to the list */
                 InsertTailList(&DiskEntry->LogicalPartListHead,
@@ -1158,6 +1182,11 @@ AddDiskToList(
     if (!NT_SUCCESS(Status))
         return;
 
+    /*
+     * Check whether the disk is initialized, by looking at its MBR.
+     * NOTE that this must be generalized to GPT disks as well!
+     */
+
     Mbr = (PARTITION_SECTOR*)RtlAllocateHeap(ProcessHeap,
                                              0,
                                              DiskGeometry.BytesPerSector);
@@ -1207,6 +1236,7 @@ AddDiskToList(
     DiskEntry->BiosFound = FALSE;
 
     /* Check if this disk has a valid MBR */
+    // FIXME: Check for the MBR signature as well, etc...
     if (Mbr->BootCode[0] == 0 && Mbr->BootCode[1] == 0)
         DiskEntry->NoMbr = TRUE;
     else
@@ -1215,6 +1245,7 @@ AddDiskToList(
     /* Free the MBR sector buffer */
     RtlFreeHeap(ProcessHeap, 0, Mbr);
 
+
     ListEntry = List->BiosDiskListHead.Flink;
     while (ListEntry != &List->BiosDiskListHead)
     {
@@ -1422,12 +1453,9 @@ CreatePartitionList(
     List->CurrentDisk = NULL;
     List->CurrentPartition = NULL;
 
-    List->SystemDisk = NULL;
     List->SystemPartition = NULL;
-    List->OriginalSystemDisk = NULL;
     List->OriginalSystemPartition = NULL;
 
-    List->TempDisk = NULL;
     List->TempPartition = NULL;
     List->FormatState = Start;
 
@@ -2739,6 +2767,7 @@ CreatePrimaryPartition(
         PartEntry->IsPartitioned = TRUE;
         PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
         PartEntry->FormatState = Unformatted;
+        PartEntry->FileSystem  = NULL;
         PartEntry->AutoCreate = AutoCreate;
         PartEntry->New = TRUE;
         PartEntry->BootIndicator = FALSE;
@@ -2776,6 +2805,7 @@ CreatePrimaryPartition(
 
         NewPartEntry->New = TRUE;
         NewPartEntry->FormatState = Unformatted;
+        NewPartEntry->FileSystem  = NULL;
         NewPartEntry->BootIndicator = FALSE;
 
         PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart;
@@ -2818,6 +2848,7 @@ AddLogicalDiskSpace(
     DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
 
     NewPartEntry->FormatState = Unformatted;
+    NewPartEntry->FileSystem  = NULL;
 
     InsertTailList(&DiskEntry->LogicalPartListHead,
                    &NewPartEntry->ListEntry);
@@ -2854,7 +2885,8 @@ CreateExtendedPartition(
 
         /* Convert current entry to 'new (unformatted)' */
         PartEntry->IsPartitioned = TRUE;
-        PartEntry->FormatState = Formatted;
+        PartEntry->FormatState = Formatted;     // FIXME? Possibly to make GetNextUnformattedPartition work (i.e. skip the extended partition container)
+        PartEntry->FileSystem  = NULL;
         PartEntry->AutoCreate = FALSE;
         PartEntry->New = FALSE;
         PartEntry->BootIndicator = FALSE;
@@ -2899,7 +2931,8 @@ CreateExtendedPartition(
                                              NewPartEntry->StartSector.QuadPart;
 
         NewPartEntry->New = FALSE;
-        NewPartEntry->FormatState = Formatted;
+        NewPartEntry->FormatState = Formatted;     // FIXME? Possibly to make GetNextUnformattedPartition work (i.e. skip the extended partition container)
+        NewPartEntry->FileSystem  = NULL;
         NewPartEntry->BootIndicator = FALSE;
 
         if (NewPartEntry->StartSector.QuadPart < 1450560)
@@ -2967,6 +3000,7 @@ CreateLogicalPartition(
         PartEntry->IsPartitioned = TRUE;
         PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
         PartEntry->FormatState = Unformatted;
+        PartEntry->FileSystem  = NULL;
         PartEntry->AutoCreate = FALSE;
         PartEntry->New = TRUE;
         PartEntry->BootIndicator = FALSE;
@@ -3005,6 +3039,7 @@ CreateLogicalPartition(
 
         NewPartEntry->New = TRUE;
         NewPartEntry->FormatState = Unformatted;
+        NewPartEntry->FileSystem  = NULL;
         NewPartEntry->BootIndicator = FALSE;
         NewPartEntry->LogicalPartition = TRUE;
 
@@ -3042,7 +3077,6 @@ DeleteCurrentPartition(
     /* Clear the system disk and partition pointers if the system partition is being deleted */
     if (List->SystemPartition == List->CurrentPartition)
     {
-        List->SystemDisk = NULL;
         List->SystemPartition = NULL;
     }
 
@@ -3122,6 +3156,7 @@ DeleteCurrentPartition(
         PartEntry->IsPartitioned = FALSE;
         PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
         PartEntry->FormatState = Unformatted;
+        PartEntry->FileSystem  = NULL;
         PartEntry->DriveLetter = 0;
     }
 
@@ -3148,9 +3183,7 @@ CheckActiveSystemPartition(
     /* Check for empty disk list */
     if (IsListEmpty(&List->DiskListHead))
     {
-        List->SystemDisk = NULL;
         List->SystemPartition = NULL;
-        List->OriginalSystemDisk = NULL;
         List->OriginalSystemPartition = NULL;
         return;
     }
@@ -3161,35 +3194,31 @@ CheckActiveSystemPartition(
     /* Check for empty partition list */
     if (IsListEmpty(&DiskEntry->PrimaryPartListHead))
     {
-        List->SystemDisk = NULL;
         List->SystemPartition = NULL;
-        List->OriginalSystemDisk = NULL;
         List->OriginalSystemPartition = NULL;
         return;
     }
 
-    if (List->SystemDisk != NULL && List->SystemPartition != NULL)
+    if (List->SystemPartition != NULL)
     {
         /* We already have an active system partition */
         DPRINT1("Use the current system partition %lu in disk %lu, drive letter %c\n",
                 List->SystemPartition->PartitionNumber,
-                List->SystemDisk->DiskNumber,
+                List->SystemPartition->DiskEntry->DiskNumber,
                 (List->SystemPartition->DriveLetter == 0) ? '-' : List->SystemPartition->DriveLetter);
         return;
     }
 
     DPRINT1("We are here (1)!\n");
 
-    List->SystemDisk = NULL;
     List->SystemPartition = NULL;
-    List->OriginalSystemDisk = NULL;
     List->OriginalSystemPartition = NULL;
 
     /* Retrieve the first partition of the disk */
     PartEntry = CONTAINING_RECORD(DiskEntry->PrimaryPartListHead.Flink,
                                   PARTENTRY,
                                   ListEntry);
-    List->SystemDisk = DiskEntry;
+    ASSERT(DiskEntry == PartEntry->DiskEntry);
     List->SystemPartition = PartEntry;
 
     //
@@ -3201,16 +3230,14 @@ CheckActiveSystemPartition(
     {
         if (PartEntry->PartitionType == PARTITION_ENTRY_UNUSED || PartEntry->BootIndicator == FALSE)
         {
-            /* FIXME: Might be incorrect if partitions were created by Linux FDISK */
+            ASSERT(DiskEntry == PartEntry->DiskEntry);
-            List->SystemDisk = DiskEntry;
             List->SystemPartition = PartEntry;
 
-            List->OriginalSystemDisk = List->SystemDisk;
             List->OriginalSystemPartition = List->SystemPartition;
 
             DPRINT1("Use new first active system partition %lu in disk %lu, drive letter %c\n",
                     List->SystemPartition->PartitionNumber,
-                    List->SystemDisk->DiskNumber,
+                    List->SystemPartition->DiskEntry->DiskNumber,
                     (List->SystemPartition->DriveLetter == 0) ? '-' : List->SystemPartition->DriveLetter);
 
             goto SetSystemPartition;
@@ -3249,22 +3276,18 @@ CheckActiveSystemPartition(
          * OK we haven't encountered any used and active partition,
          * so use the first one as the system partition.
          */
-
+        ASSERT(DiskEntry == List->SystemPartition->DiskEntry);
-        /* FIXME: Might be incorrect if partitions were created by Linux FDISK */
-        List->OriginalSystemDisk = List->SystemDisk; // DiskEntry
         List->OriginalSystemPartition = List->SystemPartition; // First PartEntry
 
         DPRINT1("Use first active system partition %lu in disk %lu, drive letter %c\n",
                 List->SystemPartition->PartitionNumber,
-                List->SystemDisk->DiskNumber,
+                List->SystemPartition->DiskEntry->DiskNumber,
                 (List->SystemPartition->DriveLetter == 0) ? '-' : List->SystemPartition->DriveLetter);
 
         goto SetSystemPartition;
     }
 
-    List->SystemDisk = NULL;
     List->SystemPartition = NULL;
-    List->OriginalSystemDisk = NULL;
     List->OriginalSystemPartition = NULL;
 
     DPRINT1("We are here (3)!\n");
@@ -3287,7 +3310,7 @@ CheckActiveSystemPartition(
             if (PartEntry->BootIndicator)
             {
                 /* Yes, we found it */
-                List->SystemDisk = DiskEntry;
+                ASSERT(DiskEntry == PartEntry->DiskEntry);
                 List->SystemPartition = PartEntry;
 
                 DPRINT1("Found active system partition %lu in disk %lu, drive letter %c\n",
@@ -3300,15 +3323,14 @@ CheckActiveSystemPartition(
     }
 
     /* Check if we have found the system partition */
-    if (List->SystemDisk == NULL || List->SystemPartition == NULL)
+    if (List->SystemPartition == NULL)
     {
         /* Nothing, use the alternative system partition */
         DPRINT1("No system partition found, use the alternative partition!\n");
         goto UseAlternativeSystemPartition;
     }
 
-    /* Save them */
+    /* Save it */
-    List->OriginalSystemDisk = List->SystemDisk;
     List->OriginalSystemPartition = List->SystemPartition;
 
     /*
@@ -3332,7 +3354,7 @@ CheckActiveSystemPartition(
     {
         DPRINT1("System partition %lu in disk %lu with no FS?!\n",
                 List->OriginalSystemPartition->PartitionNumber,
-                List->OriginalSystemDisk->DiskNumber);
+                List->OriginalSystemPartition->DiskEntry->DiskNumber);
         goto FindAndUseAlternativeSystemPartition;
     }
     // HACK: WARNING: We cannot write on this FS yet!
@@ -3347,7 +3369,7 @@ CheckActiveSystemPartition(
 
     DPRINT1("Use existing active system partition %lu in disk %lu, drive letter %c\n",
             List->SystemPartition->PartitionNumber,
-            List->SystemDisk->DiskNumber,
+            List->SystemPartition->DiskEntry->DiskNumber,
             (List->SystemPartition->DriveLetter == 0) ? '-' : List->SystemPartition->DriveLetter);
 
     return;
@@ -3364,25 +3386,24 @@ FindAndUseAlternativeSystemPartition:
 
     /* Unset the old system partition */
     List->SystemPartition->BootIndicator = FALSE;
-    List->SystemDisk->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].BootIndicator = FALSE;
+    List->SystemPartition->DiskEntry->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].BootIndicator = FALSE;
-    List->SystemDisk->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].RewritePartition = TRUE;
+    List->SystemPartition->DiskEntry->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].RewritePartition = TRUE;
-    List->SystemDisk->Dirty = TRUE;
+    List->SystemPartition->DiskEntry->Dirty = TRUE;
 
 UseAlternativeSystemPartition:
-    List->SystemDisk = List->CurrentDisk;
     List->SystemPartition = List->CurrentPartition;
 
     DPRINT1("Use alternative active system partition %lu in disk %lu, drive letter %c\n",
             List->SystemPartition->PartitionNumber,
-            List->SystemDisk->DiskNumber,
+            List->SystemPartition->DiskEntry->DiskNumber,
             (List->SystemPartition->DriveLetter == 0) ? '-' : List->SystemPartition->DriveLetter);
 
 SetSystemPartition:
     /* Set the new active system partition */
     List->SystemPartition->BootIndicator = TRUE;
-    List->SystemDisk->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].BootIndicator = TRUE;
+    List->SystemPartition->DiskEntry->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].BootIndicator = TRUE;
-    List->SystemDisk->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].RewritePartition = TRUE;
+    List->SystemPartition->DiskEntry->LayoutBuffer->PartitionEntry[List->SystemPartition->PartitionIndex].RewritePartition = TRUE;
-    List->SystemDisk->Dirty = TRUE;
+    List->SystemPartition->DiskEntry->Dirty = TRUE;
 }
 
 
@@ -3449,6 +3470,16 @@ WritePartitions(
     if (FileHandle != NULL)
         NtClose(FileHandle);
 
+    //
+    // NOTE: Originally (see r40437), we used to install here also a new MBR
+    // for this disk (by calling InstallMbrBootCodeToDisk), only if:
+    // DiskEntry->NewDisk == TRUE and DiskEntry->BiosDiskNumber == 0.
+    // Then after that, both DiskEntry->NewDisk and DiskEntry->NoMbr were set
+    // to FALSE. In the other place (in usetup.c) where InstallMbrBootCodeToDisk
+    // was called too, the installation test was modified by checking whether
+    // DiskEntry->NoMbr was TRUE (instead of NewDisk).
+    //
+
     return Status;
 }
 
@@ -3522,12 +3553,47 @@ SetMountedDeviceValues(
             Entry2 = Entry2->Flink;
         }
 
+        Entry2 = DiskEntry->LogicalPartListHead.Flink;
+        while (Entry2 != &DiskEntry->LogicalPartListHead)
+        {
+            PartEntry = CONTAINING_RECORD(Entry2, PARTENTRY, ListEntry);
+            if (PartEntry->IsPartitioned)
+            {
+                /* Assign a "\DosDevices\#:" mount point to this partition */
+                if (PartEntry->DriveLetter)
+                {
+                    StartingOffset.QuadPart = PartEntry->StartSector.QuadPart * DiskEntry->BytesPerSector;
+                    if (!SetMountedDeviceValue(PartEntry->DriveLetter,
+                                               DiskEntry->LayoutBuffer->Signature,
+                                               StartingOffset))
+                    {
+                        return FALSE;
+                    }
+                }
+            }
+
+            Entry2 = Entry2->Flink;
+        }
+
         Entry1 = Entry1->Flink;
     }
 
     return TRUE;
 }
 
+VOID
+SetPartitionType(
+    IN PPARTENTRY PartEntry,
+    IN UCHAR PartitionType)
+{
+    PDISKENTRY DiskEntry = PartEntry->DiskEntry;
+
+    PartEntry->PartitionType = PartitionType;
+
+    DiskEntry->Dirty = TRUE;
+    DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].PartitionType = PartitionType;
+    DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RewritePartition = TRUE;
+}
 
 ULONG
 PrimaryPartitionCreationChecks(
@@ -3618,7 +3684,8 @@ GetNextUnformattedPartition(
             PartEntry = CONTAINING_RECORD(Entry2, PARTENTRY, ListEntry);
             if (PartEntry->IsPartitioned && PartEntry->New)
             {
-                 *pDiskEntry = DiskEntry;
+                ASSERT(DiskEntry == PartEntry->DiskEntry);
+                if (pDiskEntry) *pDiskEntry = DiskEntry;
                 *pPartEntry = PartEntry;
                 return TRUE;
             }
@@ -3632,7 +3699,8 @@ GetNextUnformattedPartition(
             PartEntry = CONTAINING_RECORD(Entry2, PARTENTRY, ListEntry);
             if (PartEntry->IsPartitioned && PartEntry->New)
             {
-                 *pDiskEntry = DiskEntry;
+                ASSERT(DiskEntry == PartEntry->DiskEntry);
+                if (pDiskEntry) *pDiskEntry = DiskEntry;
                 *pPartEntry = PartEntry;
                 return TRUE;
             }
@@ -3643,7 +3711,7 @@ GetNextUnformattedPartition(
         Entry1 = Entry1->Flink;
     }
 
-    *pDiskEntry = NULL;
+    if (pDiskEntry) *pDiskEntry = NULL;
     *pPartEntry = NULL;
 
     return FALSE;
@@ -3672,7 +3740,8 @@ GetNextUncheckedPartition(
             PartEntry = CONTAINING_RECORD(Entry2, PARTENTRY, ListEntry);
             if (PartEntry->NeedsCheck == TRUE)
             {
-                 *pDiskEntry = DiskEntry;
+                ASSERT(DiskEntry == PartEntry->DiskEntry);
+                if (pDiskEntry) *pDiskEntry = DiskEntry;
                 *pPartEntry = PartEntry;
                 return TRUE;
             }
@@ -3686,7 +3755,8 @@ GetNextUncheckedPartition(
             PartEntry = CONTAINING_RECORD(Entry2, PARTENTRY, ListEntry);
             if (PartEntry->NeedsCheck == TRUE)
             {
-                 *pDiskEntry = DiskEntry;
+                ASSERT(DiskEntry == PartEntry->DiskEntry);
+                if (pDiskEntry) *pDiskEntry = DiskEntry;
                 *pPartEntry = PartEntry;
                 return TRUE;
             }
@@ -3697,7 +3767,7 @@ GetNextUncheckedPartition(
         Entry1 = Entry1->Flink;
     }
 
-    *pDiskEntry = NULL;
+    if (pDiskEntry) *pDiskEntry = NULL;
     *pPartEntry = NULL;
 
     return FALSE;

base/setup/usetup/partlist.h

@@ -51,16 +51,18 @@ typedef struct _PARTENTRY
 {
     LIST_ENTRY ListEntry;
 
+    /* The disk this partition belongs to */
     struct _DISKENTRY *DiskEntry;
 
+    /* Partition geometry */
     ULARGE_INTEGER StartSector;
     ULARGE_INTEGER SectorCount;
 
     BOOLEAN BootIndicator;
     UCHAR PartitionType;
     ULONG HiddenSectors;
-    ULONG PartitionNumber;
+    ULONG PartitionNumber;  /* Enumerated partition number (primary partitions first -- excluding the extended partition container --, then the logical partitions) */
-    ULONG PartitionIndex;
+    ULONG PartitionIndex;   /* Index in the LayoutBuffer->PartitionEntry[] cached array of the corresponding DiskEntry */
 
     CHAR DriveLetter;
 
@@ -75,12 +77,12 @@ typedef struct _PARTENTRY
     /* Partition was created automatically */
     BOOLEAN AutoCreate;
 
-    FORMATSTATE FormatState;
-
     /* Partition must be checked */
     BOOLEAN NeedsCheck;
 
+    FORMATSTATE FormatState;
     struct _FILE_SYSTEM_ITEM *FileSystem;
+
 } PARTENTRY, *PPARTENTRY;
 
 
@@ -100,6 +102,8 @@ typedef struct _DISKENTRY
 {
     LIST_ENTRY ListEntry;
 
+    /* Disk geometry */
+
     ULONGLONG Cylinders;
     ULONG TracksPerCylinder;
     ULONG SectorsPerTrack;
@@ -109,11 +113,13 @@ typedef struct _DISKENTRY
     ULONG SectorAlignment;
     ULONG CylinderAlignment;
 
+    /* BIOS parameters */
     BOOLEAN BiosFound;
     ULONG BiosDiskNumber;
 //    ULONG Signature;
 //    ULONG Checksum;
 
+    /* SCSI parameters */
     ULONG DiskNumber;
     USHORT Port;
     USHORT Bus;
@@ -123,12 +129,17 @@ typedef struct _DISKENTRY
     BOOLEAN Dirty;
 
     BOOLEAN NewDisk;
-    BOOLEAN NoMbr; /* MBR is absent */
+    BOOLEAN NoMbr; /* MBR is absent */  // See r40437
 
     UNICODE_STRING DriverName;
 
     PDRIVE_LAYOUT_INFORMATION LayoutBuffer;
+    // TODO: When adding support for GPT disks:
+    // Use PDRIVE_LAYOUT_INFORMATION_EX which indicates whether
+    // the disk is MBR, GPT, or unknown (uninitialized).
+    // Depending on the style, either use the MBR or GPT partition info.
 
+    /* Pointer to the unique extended partition on this disk */
     PPARTENTRY ExtendedPartition;
 
     LIST_ENTRY PrimaryPartListHead;
@@ -139,6 +150,7 @@ typedef struct _DISKENTRY
 
 typedef struct _PARTLIST
 {
+    /* UI stuff */
     SHORT Left;
     SHORT Top;
     SHORT Right;
@@ -147,23 +159,32 @@ typedef struct _PARTLIST
     SHORT Line;
     SHORT Offset;
 
+    /*
+     * NOTE that when CurrentPartition != NULL, then CurrentPartition->DiskEntry
+     * must be the same as CurrentDisk. We should however keep the two members
+     * separated as we can have a current (selected) disk without any current
+     * partition, if the former does not contain any.
+     */
     PDISKENTRY CurrentDisk;
     PPARTENTRY CurrentPartition;
 
-    /* The system disk and partition where the boot manager resides */
+    /*
-    PDISKENTRY SystemDisk;
+     * The system partition where the boot manager resides.
+     * The corresponding system disk is obtained via:
+     *    SystemPartition->DiskEntry.
+     */
     PPARTENTRY SystemPartition;
     /*
-     * The original system disk and partition in case we are redefining them
+     * The original system partition in case we are redefining it because
-     * because we do not have write support on them.
+     * we do not have write support on it.
-     * Please not that this is partly a HACK and MUST NEVER happen on
+     * Please note that this is partly a HACK and MUST NEVER happen on
      * architectures where real system partitions are mandatory (because then
      * they are formatted in FAT FS and we support write operation on them).
+     * The corresponding original system disk is obtained via:
+     *    OriginalSystemPartition->DiskEntry.
      */
-    PDISKENTRY OriginalSystemDisk;
     PPARTENTRY OriginalSystemPartition;
 
-    PDISKENTRY TempDisk;
     PPARTENTRY TempPartition;
     FORMATMACHINESTATE FormatState;
 
@@ -278,6 +299,11 @@ BOOLEAN
 SetMountedDeviceValues(
     IN PPARTLIST List);
 
+VOID
+SetPartitionType(
+    IN PPARTENTRY PartEntry,
+    IN UCHAR PartitionType);
+
 ULONG
 PrimaryPartitionCreationChecks(
     IN PPARTLIST List);

base/setup/usetup/usetup.c

@@ -2657,9 +2657,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
 
     /* Find or set the active system partition */
     CheckActiveSystemPartition(PartitionList, FileSystemList);
-
+    if (PartitionList->SystemPartition == NULL)
-    if (PartitionList->SystemDisk == NULL ||
-        PartitionList->SystemPartition == NULL)
     {
         /* FIXME: show an error dialog */
         return QUIT_PAGE;
@@ -2671,7 +2669,6 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
         case Start:
             if (PartitionList->CurrentPartition != PartitionList->SystemPartition)
             {
-                PartitionList->TempDisk = PartitionList->SystemDisk;
                 PartitionList->TempPartition = PartitionList->SystemPartition;
                 PartitionList->TempPartition->NeedsCheck = TRUE;
 
@@ -2680,7 +2677,6 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
             }
             else
             {
-                PartitionList->TempDisk = PartitionList->CurrentDisk;
                 PartitionList->TempPartition = PartitionList->CurrentPartition;
                 PartitionList->TempPartition->NeedsCheck = TRUE;
 
@@ -2690,7 +2686,6 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
             break;
 
         case FormatSystemPartition:
-            PartitionList->TempDisk = PartitionList->CurrentDisk;
             PartitionList->TempPartition = PartitionList->CurrentPartition;
             PartitionList->TempPartition->NeedsCheck = TRUE;
 
@@ -2700,7 +2695,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
 
         case FormatInstallPartition:
             if (GetNextUnformattedPartition(PartitionList,
-                                            &PartitionList->TempDisk,
+                                            NULL,
                                             &PartitionList->TempPartition))
             {
                 PartitionList->FormatState = FormatOtherPartition;
@@ -2717,7 +2712,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
 
         case FormatOtherPartition:
             if (GetNextUnformattedPartition(PartitionList,
-                                            &PartitionList->TempDisk,
+                                            NULL,
                                             &PartitionList->TempPartition))
             {
                 PartitionList->FormatState = FormatOtherPartition;
@@ -2738,8 +2733,8 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
             return QUIT_PAGE;
     }
 
-    DiskEntry = PartitionList->TempDisk;
     PartEntry = PartitionList->TempPartition;
+    DiskEntry = PartEntry->DiskEntry;
 
     /* Adjust disk size */
     DiskSize = DiskEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
@@ -2970,15 +2965,14 @@ FormatPartitionPage(PINPUT_RECORD Ir)
     MUIDisplayPage(FORMAT_PARTITION_PAGE);
 
     if (PartitionList == NULL ||
-        PartitionList->TempDisk == NULL ||
         PartitionList->TempPartition == NULL)
     {
         /* FIXME: show an error dialog */
         return QUIT_PAGE;
     }
 
-    DiskEntry = PartitionList->TempDisk;
     PartEntry = PartitionList->TempPartition;
+    DiskEntry = PartEntry->DiskEntry;
 
     while (TRUE)
     {
@@ -3004,7 +2998,7 @@ FormatPartitionPage(PINPUT_RECORD Ir)
                 if (PartEntry->SectorCount.QuadPart < 8192)
                 {
                     /* FAT12 CHS partition (disk is smaller than 4.1MB) */
-                    PartEntry->PartitionType = PARTITION_FAT_12;
+                    SetPartitionType(PartEntry, PARTITION_FAT_12);
                 }
                 else if (PartEntry->StartSector.QuadPart < 1450560)
                 {
@@ -3013,17 +3007,17 @@ FormatPartitionPage(PINPUT_RECORD Ir)
                     if (PartEntry->SectorCount.QuadPart < 65536)
                     {
                         /* FAT16 CHS partition (partition size < 32MB) */
-                        PartEntry->PartitionType = PARTITION_FAT_16;
+                        SetPartitionType(PartEntry, PARTITION_FAT_16);
                     }
                     else if (PartEntry->SectorCount.QuadPart < 1048576)
                     {
                         /* FAT16 CHS partition (partition size < 512MB) */
-                        PartEntry->PartitionType = PARTITION_HUGE;
+                        SetPartitionType(PartEntry, PARTITION_HUGE);
                     }
                     else
                     {
                         /* FAT32 CHS partition (partition size >= 512MB) */
-                        PartEntry->PartitionType = PARTITION_FAT32;
+                        SetPartitionType(PartEntry, PARTITION_FAT32);
                     }
                 }
                 else
@@ -3033,35 +3027,23 @@ FormatPartitionPage(PINPUT_RECORD Ir)
                     if (PartEntry->SectorCount.QuadPart < 1048576)
                     {
                         /* FAT16 LBA partition (partition size < 512MB) */
-                        PartEntry->PartitionType = PARTITION_XINT13;
+                        SetPartitionType(PartEntry, PARTITION_XINT13);
                     }
                     else
                     {
                         /* FAT32 LBA partition (partition size >= 512MB) */
-                        PartEntry->PartitionType = PARTITION_FAT32_XINT13;
+                        SetPartitionType(PartEntry, PARTITION_FAT32_XINT13);
                     }
                 }
-
-                DiskEntry->Dirty = TRUE;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].PartitionType = PartEntry->PartitionType;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RewritePartition = TRUE;
             }
 #if 0
             else if (wcscmp(PartEntry->FileSystem->FileSystemName, L"EXT2") == 0)
             {
-                PartEntry->PartitionType = PARTITION_EXT2;
+                SetPartitionType(PartEntry, PARTITION_EXT2);
-
-                DiskEntry->Dirty = TRUE;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].PartitionType = PartEntry->PartitionType;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RewritePartition = TRUE;
             }
             else if (wcscmp(PartEntry->FileSystem->FileSystemName, L"NTFS") == 0)
             {
-                PartEntry->PartitionType = PARTITION_IFS;
+                SetPartitionType(PartEntry, PARTITION_IFS);
-
-                DiskEntry->Dirty = TRUE;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].PartitionType = PartEntry->PartitionType;
-                DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RewritePartition = TRUE;
             }
 #endif
             else if (!PartEntry->FileSystem->FormatFunc)
@@ -4284,7 +4266,7 @@ BootLoaderPage(PINPUT_RECORD Ir)
     RtlFreeUnicodeString(&SystemRootPath);
     swprintf(PathBuffer,
              L"\\Device\\Harddisk%lu\\Partition%lu",
-             PartitionList->SystemDisk->DiskNumber,
+             PartitionList->SystemPartition->DiskEntry->DiskNumber,
              PartitionList->SystemPartition->PartitionNumber);
     RtlCreateUnicodeString(&SystemRootPath, PathBuffer);
     DPRINT1("SystemRootPath: %wZ\n", &SystemRootPath);
@@ -4557,7 +4539,7 @@ BootLoaderHarddiskMbrPage(PINPUT_RECORD Ir)
     /* Step 2: Write the MBR */
     swprintf(DestinationDevicePathBuffer,
              L"\\Device\\Harddisk%d\\Partition0",
-             PartitionList->SystemDisk->DiskNumber);
+             PartitionList->SystemPartition->DiskEntry->DiskNumber);
 
     wcscpy(SourceMbrPathBuffer, SourceRootPath.Buffer);
     wcscat(SourceMbrPathBuffer, L"\\loader\\dosmbr.bin");