[ros-diffs] [reactos] 01/03: [SETUPLIB] Partitioning code fixes and improvements.

[Hermès Bélusca-Maïto]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=7df92966921e4501d5a24…

commit 7df92966921e4501d5a24c0ca37078d6ec1b5057
Author:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
AuthorDate: Thu Nov 22 03:26:47 2018 +0100
Commit:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
CommitDate: Mon Dec 10 00:27:56 2018 +0100

    [SETUPLIB] Partitioning code fixes and improvements.
    
    CORE-7749
    
    - Correctly insert discovered partitions in sorted order of StartSector,
      and verify that they do not overlap (-> check for broken partitioning).
    
    May help for CORE-10898.
    
    - Use the correct reported partition numbers that may be modified after
      partitioning changes, and that need to be used when opening
      \Device\Harddisk'M'\Partition'N' files. This is achieving by
      retrieving the returned value of the IOCTL_DISK_SET_DRIVE_LAYOUT call.
    
      Distinguish them from the "on-disk" partition numbers that are the ones
      that enumerate the partition in partition-table order (and is the order
      known by e.g. the BIOS), and that should be used to construct the
      destination ARC path.
    
    May help for CORE-4870, CORE-13205.
    
    - Simplify a lot of duplicated code by using helper functions.
---
 base/setup/lib/setuplib.c       |   2 +-
 base/setup/lib/utils/partlist.c | 776 +++++++++++++++++++++-------------------
 base/setup/lib/utils/partlist.h |  17 +-
 3 files changed, 413 insertions(+), 382 deletions(-)

diff --git a/base/setup/lib/setuplib.c b/base/setup/lib/setuplib.c
index c63c5dfb87..1bbdaa8f3e 100644
--- a/base/setup/lib/setuplib.c
+++ b/base/setup/lib/setuplib.c
@@ -642,7 +642,7 @@ InitDestinationPaths(
     RtlStringCchPrintfW(PathBuffer, ARRAYSIZE(PathBuffer),
             L"multi(0)disk(0)rdisk(%lu)partition(%lu)\\",
             DiskEntry->BiosDiskNumber,
-            PartEntry->PartitionNumber);
+            PartEntry->OnDiskPartitionNumber);
     ConcatPaths(PathBuffer, ARRAYSIZE(PathBuffer), 1, InstallationDir);
     RtlCreateUnicodeString(&pSetupData->DestinationArcPath, PathBuffer);
 
diff --git a/base/setup/lib/utils/partlist.c b/base/setup/lib/utils/partlist.c
index 89178ae014..fc47c6376d 100644
--- a/base/setup/lib/utils/partlist.c
+++ b/base/setup/lib/utils/partlist.c
@@ -664,6 +664,187 @@ EnumerateBiosDiskEntries(
 #undef ROOT_NAME
 }
 
+
+
+/*
+ * Inserts the disk region represented by PartEntry into either the primary
+ * or the logical partition list of the given disk.
+ * The lists are kept sorted by increasing order of start sectors.
+ * Of course no disk region should overlap at all with one another.
+ */
+static
+VOID
+InsertDiskRegion(
+    IN PDISKENTRY DiskEntry,
+    IN PPARTENTRY PartEntry,
+    IN BOOLEAN LogicalPartition)
+{
+    PLIST_ENTRY List;
+    PLIST_ENTRY Entry;
+    PPARTENTRY PartEntry2;
+
+    /* Use the correct partition list */
+    if (LogicalPartition)
+        List = &DiskEntry->LogicalPartListHead;
+    else
+        List = &DiskEntry->PrimaryPartListHead;
+
+    /* Find the first disk region before which we need to insert the new one */
+    for (Entry = List->Flink; Entry != List; Entry = Entry->Flink)
+    {
+        PartEntry2 = CONTAINING_RECORD(Entry, PARTENTRY, ListEntry);
+
+        /* Ignore any unused empty region */
+        if ((PartEntry2->PartitionType == PARTITION_ENTRY_UNUSED &&
+             PartEntry2->StartSector.QuadPart == 0) ||
PartEntry2->SectorCount.QuadPart == 0)
+        {
+            continue;
+        }
+
+        /* If the current region ends before the one to be inserted, try again */
+        if (PartEntry2->StartSector.QuadPart + PartEntry2->SectorCount.QuadPart - 1
< PartEntry->StartSector.QuadPart)
+            continue;
+
+        /*
+         * One of the disk region boundaries crosses the desired region
+         * (it starts after the desired region, or ends before the end
+         * of the desired region): this is an impossible situation because
+         * disk regions (partitions) cannot overlap!
+         * Throw an error and bail out.
+         */
+        if (max(PartEntry->StartSector.QuadPart, PartEntry2->StartSector.QuadPart)
+            <=
+            min( PartEntry->StartSector.QuadPart +  PartEntry->SectorCount.QuadPart
- 1,
+                PartEntry2->StartSector.QuadPart + PartEntry2->SectorCount.QuadPart
- 1))
+        {
+            DPRINT1("Disk region overlap problem, stopping there!\n"
+                    "Partition to be inserted:\n"
+                    "    StartSector = %I64u ; EndSector = %I64u\n"
+                    "Existing disk region:\n"
+                    "    StartSector = %I64u ; EndSector = %I64u\n",
+                     PartEntry->StartSector.QuadPart,
+                     PartEntry->StartSector.QuadPart + 
PartEntry->SectorCount.QuadPart - 1,
+                    PartEntry2->StartSector.QuadPart,
+                    PartEntry2->StartSector.QuadPart +
PartEntry2->SectorCount.QuadPart - 1);
+            return;
+        }
+
+        /* We have found the first region before which the new one has to be inserted */
+        break;
+    }
+
+    /* Insert the disk region */
+    InsertTailList(Entry, &PartEntry->ListEntry);
+}
+
+static
+PPARTENTRY
+CreateInsertBlankRegion(
+    IN PDISKENTRY DiskEntry,
+    IN OUT PLIST_ENTRY ListHead,
+    IN ULONGLONG StartSector,
+    IN ULONGLONG SectorCount,
+    IN BOOLEAN LogicalSpace)
+{
+    PPARTENTRY NewPartEntry;
+
+    NewPartEntry = RtlAllocateHeap(ProcessHeap,
+                                   HEAP_ZERO_MEMORY,
+                                   sizeof(PARTENTRY));
+    if (NewPartEntry == NULL)
+        return NULL;
+
+    NewPartEntry->DiskEntry = DiskEntry;
+
+    NewPartEntry->IsPartitioned = FALSE;
+    NewPartEntry->FormatState = Unformatted;
+    NewPartEntry->FileSystem  = NULL;
+
+    NewPartEntry->StartSector.QuadPart = StartSector;
+    NewPartEntry->SectorCount.QuadPart = SectorCount;
+
+    DPRINT1("First Sector : %I64u\n", NewPartEntry->StartSector.QuadPart);
+    DPRINT1("Last Sector  : %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
+    DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
+
+    /* Insert the table into the list */
+    InsertTailList(ListHead, &NewPartEntry->ListEntry);
+
+    return NewPartEntry;
+}
+
+static
+// BOOLEAN
+PPARTENTRY
+InitializePartitionEntry(
+    IN PDISKENTRY DiskEntry,
+    IN PPARTENTRY PartEntry,
+    IN ULONGLONG SectorCount,
+    IN BOOLEAN AutoCreate)
+{
+    PPARTENTRY NewPartEntry;
+
+    DPRINT1("Current partition sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
+
+    if ((AutoCreate != FALSE) ||
+        (AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
+                   PartEntry->StartSector.QuadPart ==
PartEntry->SectorCount.QuadPart))
+    {
+        DPRINT1("Convert existing partition entry\n");
+
+        /* Convert current entry to 'new (unformatted)' */
+        PartEntry->IsPartitioned = TRUE;
+        PartEntry->New = TRUE;
+        PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
+        PartEntry->FormatState = Unformatted;
+        PartEntry->FileSystem  = NULL;
+        PartEntry->AutoCreate = AutoCreate;
+        PartEntry->BootIndicator = FALSE;
+        PartEntry->LogicalPartition = FALSE;
+
+        NewPartEntry = PartEntry;
+    }
+    else
+    {
+        DPRINT1("Add new partition entry\n");
+
+        /* Insert and initialize a new partition entry */
+        NewPartEntry = RtlAllocateHeap(ProcessHeap,
+                                       HEAP_ZERO_MEMORY,
+                                       sizeof(PARTENTRY));
+        if (NewPartEntry == NULL)
+            return NULL;
+
+        /* Insert the new entry into the list */
+        InsertTailList(&PartEntry->ListEntry,
+                       &NewPartEntry->ListEntry);
+
+        NewPartEntry->DiskEntry = DiskEntry;
+
+        NewPartEntry->IsPartitioned = TRUE;
+        NewPartEntry->New = TRUE;
+        NewPartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
+        NewPartEntry->FormatState = Unformatted;
+        NewPartEntry->FileSystem  = NULL;
+        NewPartEntry->BootIndicator = FALSE;
+        NewPartEntry->LogicalPartition = FALSE;
+
+        NewPartEntry->StartSector.QuadPart = PartEntry->StartSector.QuadPart;
+        NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
+                                             NewPartEntry->StartSector.QuadPart;
+
+        PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart;
+        PartEntry->SectorCount.QuadPart -= (PartEntry->StartSector.QuadPart -
NewPartEntry->StartSector.QuadPart);
+    }
+
+    DPRINT1("First Sector : %I64u\n", NewPartEntry->StartSector.QuadPart);
+    DPRINT1("Last Sector  : %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
+    DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
+
+    return NewPartEntry;
+}
+
+
 static
 VOID
 AddPartitionToDisk(
@@ -708,6 +889,7 @@ AddPartitionToDisk(
 
     PartEntry->LogicalPartition = LogicalPartition;
     PartEntry->IsPartitioned = TRUE;
+    PartEntry->OnDiskPartitionNumber = PartitionInfo->PartitionNumber;
     PartEntry->PartitionNumber = PartitionInfo->PartitionNumber;
     PartEntry->PartitionIndex = PartitionIndex;
 
@@ -721,6 +903,8 @@ AddPartitionToDisk(
     }
     else if (IsRecognizedPartition(PartEntry->PartitionType))
     {
+        ASSERT(PartitionInfo->RecognizedPartition);
+
         PartEntry->FileSystem = GetFileSystem(PartEntry);
         if (PartEntry->FileSystem)
             PartEntry->FormatState = Preformatted;
@@ -740,7 +924,8 @@ AddPartitionToDisk(
     /* Open the volume, ignore any errors */
     RtlStringCchPrintfW(Buffer, ARRAYSIZE(Buffer),
                         L"\\Device\\Harddisk%lu\\Partition%lu",
-                        DiskEntry->DiskNumber, PartEntry->PartitionNumber);
+                        DiskEntry->DiskNumber,
+                        PartEntry->PartitionNumber);
     RtlInitUnicodeString(&Name, Buffer);
 
     InitializeObjectAttributes(&ObjectAttributes,
@@ -783,12 +968,7 @@ AddPartitionToDisk(
         DPRINT1("NtOpenFile() failed, Status 0x%08lx\n", Status);
     }
 
-    if (LogicalPartition)
-        InsertTailList(&DiskEntry->LogicalPartListHead,
-                       &PartEntry->ListEntry);
-    else
-        InsertTailList(&DiskEntry->PrimaryPartListHead,
-                       &PartEntry->ListEntry);
+    InsertDiskRegion(DiskEntry, PartEntry, LogicalPartition);
 }
 
 static
@@ -796,6 +976,8 @@ VOID
 ScanForUnpartitionedDiskSpace(
     IN PDISKENTRY DiskEntry)
 {
+    ULONGLONG StartSector;
+    ULONGLONG SectorCount;
     ULONGLONG LastStartSector;
     ULONGLONG LastSectorCount;
     ULONGLONG LastUnusedSectorCount;
@@ -810,31 +992,20 @@ ScanForUnpartitionedDiskSpace(
         DPRINT1("No primary partition!\n");
 
         /* Create a partition entry that represents the empty disk */
-        NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                       HEAP_ZERO_MEMORY,
-                                       sizeof(PARTENTRY));
-        if (NewPartEntry == NULL)
-            return;
-
-        NewPartEntry->DiskEntry = DiskEntry;
 
-        NewPartEntry->IsPartitioned = FALSE;
         if (DiskEntry->SectorAlignment < 2048)
-            NewPartEntry->StartSector.QuadPart = 2048ULL;
+            StartSector = 2048ULL;
         else
-            NewPartEntry->StartSector.QuadPart =
(ULONGLONG)DiskEntry->SectorAlignment;
-        NewPartEntry->SectorCount.QuadPart =
AlignDown(DiskEntry->SectorCount.QuadPart, DiskEntry->SectorAlignment) -
-                                             NewPartEntry->StartSector.QuadPart;
-
-        DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-        NewPartEntry->FormatState = Unformatted;
-        NewPartEntry->FileSystem  = NULL;
-
-        InsertTailList(&DiskEntry->PrimaryPartListHead,
-                       &NewPartEntry->ListEntry);
+            StartSector = (ULONGLONG)DiskEntry->SectorAlignment;
+        SectorCount = AlignDown(DiskEntry->SectorCount.QuadPart,
DiskEntry->SectorAlignment) - StartSector;
+
+        NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                               &DiskEntry->PrimaryPartListHead,
+                                               StartSector,
+                                               SectorCount,
+                                               FALSE);
+        if (NewPartEntry == NULL)
+            DPRINT1("Failed to create a new empty region for full disk
space!\n");
 
         return;
     }
@@ -843,7 +1014,7 @@ ScanForUnpartitionedDiskSpace(
     if (DiskEntry->SectorAlignment < 2048)
         LastStartSector = 2048ULL;
     else
-        LastStartSector = DiskEntry->SectorAlignment;
+        LastStartSector = (ULONGLONG)DiskEntry->SectorAlignment;
     LastSectorCount = 0ULL;
     LastUnusedSectorCount = 0ULL;
 
@@ -863,29 +1034,20 @@ ScanForUnpartitionedDiskSpace(
             {
                 DPRINT("Unpartitioned disk space %I64u sectors\n",
LastUnusedSectorCount);
 
-                NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                               HEAP_ZERO_MEMORY,
-                                               sizeof(PARTENTRY));
-                if (NewPartEntry == NULL)
-                    return;
-
-                NewPartEntry->DiskEntry = DiskEntry;
-
-                NewPartEntry->IsPartitioned = FALSE;
-                NewPartEntry->StartSector.QuadPart = LastStartSector +
LastSectorCount;
-                NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + LastUnusedSectorCount,
DiskEntry->SectorAlignment) -
-                                                    
NewPartEntry->StartSector.QuadPart;
-
-                DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-                DPRINT1("Last Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-                DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-                NewPartEntry->FormatState = Unformatted;
-                NewPartEntry->FileSystem  = NULL;
+                StartSector = LastStartSector + LastSectorCount;
+                SectorCount = AlignDown(StartSector + LastUnusedSectorCount,
DiskEntry->SectorAlignment) - StartSector;
 
                 /* Insert the table into the list */
-                InsertTailList(&PartEntry->ListEntry,
-                               &NewPartEntry->ListEntry);
+                NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                                       &PartEntry->ListEntry,
+                                                       StartSector,
+                                                       SectorCount,
+                                                       FALSE);
+                if (NewPartEntry == NULL)
+                {
+                    DPRINT1("Failed to create a new empty region for disk
space!\n");
+                    return;
+                }
             }
 
             LastStartSector = PartEntry->StartSector.QuadPart;
@@ -904,29 +1066,20 @@ ScanForUnpartitionedDiskSpace(
         {
             DPRINT("Unpartitioned disk space: %I64u sectors\n",
LastUnusedSectorCount);
 
-            NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                           HEAP_ZERO_MEMORY,
-                                           sizeof(PARTENTRY));
-            if (NewPartEntry == NULL)
-                return;
-
-            NewPartEntry->DiskEntry = DiskEntry;
-
-            NewPartEntry->IsPartitioned = FALSE;
-            NewPartEntry->StartSector.QuadPart = LastStartSector + LastSectorCount;
-            NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + LastUnusedSectorCount,
DiskEntry->SectorAlignment) -
-                                                 NewPartEntry->StartSector.QuadPart;
-
-            DPRINT("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-            DPRINT("Last Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-            DPRINT("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-            NewPartEntry->FormatState = Unformatted;
-            NewPartEntry->FileSystem  = NULL;
+            StartSector = LastStartSector + LastSectorCount;
+            SectorCount = AlignDown(StartSector + LastUnusedSectorCount,
DiskEntry->SectorAlignment) - StartSector;
 
             /* Append the table to the list */
-            InsertTailList(&DiskEntry->PrimaryPartListHead,
-                           &NewPartEntry->ListEntry);
+            NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                                  
&DiskEntry->PrimaryPartListHead,
+                                                   StartSector,
+                                                   SectorCount,
+                                                   FALSE);
+            if (NewPartEntry == NULL)
+            {
+                DPRINT1("Failed to create a new empty region for trailing disk
space!\n");
+                return;
+            }
         }
     }
 
@@ -937,29 +1090,22 @@ ScanForUnpartitionedDiskSpace(
             DPRINT1("No logical partition!\n");
 
             /* Create a partition entry that represents the empty extended partition */
-            NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                           HEAP_ZERO_MEMORY,
-                                           sizeof(PARTENTRY));
+
+            StartSector = DiskEntry->ExtendedPartition->StartSector.QuadPart +
(ULONGLONG)DiskEntry->SectorAlignment;
+            SectorCount = DiskEntry->ExtendedPartition->SectorCount.QuadPart -
(ULONGLONG)DiskEntry->SectorAlignment;
+
+            NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                                  
&DiskEntry->LogicalPartListHead,
+                                                   StartSector,
+                                                   SectorCount,
+                                                   TRUE);
             if (NewPartEntry == NULL)
+            {
+                DPRINT1("Failed to create a new empty region for full extended
partition space!\n");
                 return;
-
-            NewPartEntry->DiskEntry = DiskEntry;
+            }
             NewPartEntry->LogicalPartition = TRUE;
 
-            NewPartEntry->IsPartitioned = FALSE;
-            NewPartEntry->StartSector.QuadPart =
DiskEntry->ExtendedPartition->StartSector.QuadPart +
(ULONGLONG)DiskEntry->SectorAlignment;
-            NewPartEntry->SectorCount.QuadPart =
DiskEntry->ExtendedPartition->SectorCount.QuadPart -
(ULONGLONG)DiskEntry->SectorAlignment;
-
-            DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-            DPRINT1("Last Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-            DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-            NewPartEntry->FormatState = Unformatted;
-            NewPartEntry->FileSystem  = NULL;
-
-            InsertTailList(&DiskEntry->LogicalPartListHead,
-                           &NewPartEntry->ListEntry);
-
             return;
         }
 
@@ -984,30 +1130,21 @@ ScanForUnpartitionedDiskSpace(
                 {
                     DPRINT("Unpartitioned disk space %I64u sectors\n",
LastUnusedSectorCount);
 
-                    NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                                   HEAP_ZERO_MEMORY,
-                                                   sizeof(PARTENTRY));
+                    StartSector = LastStartSector + LastSectorCount;
+                    SectorCount = AlignDown(StartSector + LastUnusedSectorCount,
DiskEntry->SectorAlignment) - StartSector;
+
+                    /* Insert the table into the list */
+                    NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                                           &PartEntry->ListEntry,
+                                                           StartSector,
+                                                           SectorCount,
+                                                           TRUE);
                     if (NewPartEntry == NULL)
+                    {
+                        DPRINT1("Failed to create a new empty region for extended
partition space!\n");
                         return;
-
-                    NewPartEntry->DiskEntry = DiskEntry;
+                    }
                     NewPartEntry->LogicalPartition = TRUE;
-
-                    NewPartEntry->IsPartitioned = FALSE;
-                    NewPartEntry->StartSector.QuadPart = LastStartSector +
LastSectorCount;
-                    NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + LastUnusedSectorCount,
DiskEntry->SectorAlignment) -
-                                                        
NewPartEntry->StartSector.QuadPart;
-
-                    DPRINT("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-                    DPRINT("Last Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-                    DPRINT("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-                    NewPartEntry->FormatState = Unformatted;
-                    NewPartEntry->FileSystem  = NULL;
-
-                    /* Insert the table into the list */
-                    InsertTailList(&PartEntry->ListEntry,
-                                   &NewPartEntry->ListEntry);
                 }
 
                 LastStartSector = PartEntry->StartSector.QuadPart;
@@ -1020,36 +1157,29 @@ ScanForUnpartitionedDiskSpace(
         /* Check for trailing unpartitioned disk space */
         if ((LastStartSector + LastSectorCount) <
DiskEntry->ExtendedPartition->StartSector.QuadPart +
DiskEntry->ExtendedPartition->SectorCount.QuadPart)
         {
-            LastUnusedSectorCount =
AlignDown(DiskEntry->ExtendedPartition->StartSector.QuadPart +
DiskEntry->ExtendedPartition->SectorCount.QuadPart - (LastStartSector +
LastSectorCount), DiskEntry->SectorAlignment);
+            LastUnusedSectorCount =
AlignDown(DiskEntry->ExtendedPartition->StartSector.QuadPart +
+                                             
DiskEntry->ExtendedPartition->SectorCount.QuadPart - (LastStartSector +
LastSectorCount),
+                                              DiskEntry->SectorAlignment);
 
             if (LastUnusedSectorCount >= (ULONGLONG)DiskEntry->SectorAlignment)
             {
                 DPRINT("Unpartitioned disk space: %I64u sectors\n",
LastUnusedSectorCount);
 
-                NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                               HEAP_ZERO_MEMORY,
-                                               sizeof(PARTENTRY));
+                StartSector = LastStartSector + LastSectorCount;
+                SectorCount = AlignDown(StartSector + LastUnusedSectorCount,
DiskEntry->SectorAlignment) - StartSector;
+
+                /* Append the table to the list */
+                NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                                      
&DiskEntry->LogicalPartListHead,
+                                                       StartSector,
+                                                       SectorCount,
+                                                       TRUE);
                 if (NewPartEntry == NULL)
+                {
+                    DPRINT1("Failed to create a new empty region for extended
partition space!\n");
                     return;
-
-                NewPartEntry->DiskEntry = DiskEntry;
+                }
                 NewPartEntry->LogicalPartition = TRUE;
-
-                NewPartEntry->IsPartitioned = FALSE;
-                NewPartEntry->StartSector.QuadPart = LastStartSector +
LastSectorCount;
-                NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + LastUnusedSectorCount,
DiskEntry->SectorAlignment) -
-                                                    
NewPartEntry->StartSector.QuadPart;
-
-                DPRINT("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-                DPRINT("Last Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-                DPRINT("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-                NewPartEntry->FormatState = Unformatted;
-                NewPartEntry->FileSystem  = NULL;
-
-                /* Append the table to the list */
-                InsertTailList(&DiskEntry->LogicalPartListHead,
-                               &NewPartEntry->ListEntry);
             }
         }
     }
@@ -1433,22 +1563,25 @@ AddDiskToList(
         DPRINT1("No valid partition table found! Use megabyte (%lu Sectors)
alignment!\n", (1024 * 1024) / DiskEntry->BytesPerSector);
     }
 
-
     if (DiskEntry->LayoutBuffer->PartitionCount == 0)
     {
         DiskEntry->NewDisk = TRUE;
         DiskEntry->LayoutBuffer->PartitionCount = 4;
 
         for (i = 0; i < 4; i++)
+        {
             DiskEntry->LayoutBuffer->PartitionEntry[i].RewritePartition = TRUE;
+        }
     }
     else
     {
+        /* Enumerate and add the first four primary partitions */
         for (i = 0; i < 4; i++)
         {
             AddPartitionToDisk(DiskNumber, DiskEntry, i, FALSE);
         }
 
+        /* Enumerate and add the remaining partitions as logical ones */
         for (i = 4; i < DiskEntry->LayoutBuffer->PartitionCount; i += 4)
         {
             AddPartitionToDisk(DiskNumber, DiskEntry, i, TRUE);
@@ -1873,7 +2006,7 @@ GetNextPartition(
         {
             /* Primary or extended partition */
 
-            if ((List->CurrentPartition->IsPartitioned != FALSE) &&
+            if (List->CurrentPartition->IsPartitioned &&
                 IsContainerPartition(List->CurrentPartition->PartitionType))
             {
                 /* First logical partition */
@@ -1966,7 +2099,7 @@ GetPrevPartition(
             {
                 PartEntry = CONTAINING_RECORD(PartListEntry, PARTENTRY, ListEntry);
 
-                if ((PartEntry->IsPartitioned != FALSE) &&
+                if (PartEntry->IsPartitioned &&
                     IsContainerPartition(PartEntry->PartitionType))
                 {
                     PartListEntry = List->CurrentDisk->LogicalPartListHead.Blink;
@@ -1990,7 +2123,7 @@ GetPrevPartition(
         {
             PartEntry = CONTAINING_RECORD(PartListEntry, PARTENTRY, ListEntry);
 
-            if ((PartEntry->IsPartitioned != FALSE) &&
+            if (PartEntry->IsPartitioned &&
                 IsContainerPartition(PartEntry->PartitionType))
             {
                 PartListEntry = DiskEntry->LogicalPartListHead.Blink;
@@ -2042,7 +2175,6 @@ IsSamePrimaryLayoutEntry(
 {
     if (PartitionInfo->StartingOffset.QuadPart == PartEntry->StartSector.QuadPart *
DiskEntry->BytesPerSector &&
         PartitionInfo->PartitionLength.QuadPart == PartEntry->SectorCount.QuadPart
* DiskEntry->BytesPerSector)
-//        PartitionInfo->PartitionNumber = PartEntry->PartitionNumber &&
 //        PartitionInfo->PartitionType == PartEntry->PartitionType
     {
         return TRUE;
@@ -2113,7 +2245,7 @@ ReAllocateLayoutBuffer(
     if (DiskEntry->LayoutBuffer)
         CurrentPartitionCount = DiskEntry->LayoutBuffer->PartitionCount;
 
-    DPRINT1("CurrentPartitionCount: %lu    NewPartitionCount: %lu\n",
+    DPRINT1("CurrentPartitionCount: %lu ; NewPartitionCount: %lu\n",
             CurrentPartitionCount, NewPartitionCount);
 
     if (CurrentPartitionCount == NewPartitionCount)
@@ -2131,15 +2263,18 @@ ReAllocateLayoutBuffer(
         return FALSE;
     }
 
+    NewLayoutBuffer->PartitionCount = NewPartitionCount;
+
     /* If the layout buffer grows, make sure the new (empty) entries are written to the
disk */
     if (NewPartitionCount > CurrentPartitionCount)
     {
         for (i = CurrentPartitionCount; i < NewPartitionCount; i++)
+        {
             NewLayoutBuffer->PartitionEntry[i].RewritePartition = TRUE;
+        }
     }
 
     DiskEntry->LayoutBuffer = NewLayoutBuffer;
-    DiskEntry->LayoutBuffer->PartitionCount = NewPartitionCount;
 
     return TRUE;
 }
@@ -2173,9 +2308,16 @@ UpdateDiskLayout(
     {
         PartEntry = CONTAINING_RECORD(ListEntry, PARTENTRY, ListEntry);
 
-        if (PartEntry->IsPartitioned != FALSE)
+        if (PartEntry->IsPartitioned)
         {
             PartitionInfo = &DiskEntry->LayoutBuffer->PartitionEntry[Index];
+            PartEntry->PartitionIndex = Index;
+
+            /* Reset the current partition number only for newly-created partitions */
+            if (PartEntry->New)
+                PartEntry->PartitionNumber = 0;
+
+            PartEntry->OnDiskPartitionNumber =
(!IsContainerPartition(PartEntry->PartitionType)) ? PartitionNumber : 0;
 
             if (!IsSamePrimaryLayoutEntry(PartitionInfo, DiskEntry, PartEntry))
             {
@@ -2184,16 +2326,13 @@ UpdateDiskLayout(
                 PartitionInfo->StartingOffset.QuadPart =
PartEntry->StartSector.QuadPart * DiskEntry->BytesPerSector;
                 PartitionInfo->PartitionLength.QuadPart =
PartEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
                 PartitionInfo->HiddenSectors = PartEntry->StartSector.LowPart;
-                PartitionInfo->PartitionNumber =
(!IsContainerPartition(PartEntry->PartitionType)) ? PartitionNumber : 0;
+                PartitionInfo->PartitionNumber = PartEntry->PartitionNumber;
                 PartitionInfo->PartitionType = PartEntry->PartitionType;
                 PartitionInfo->BootIndicator = PartEntry->BootIndicator;
-                PartitionInfo->RecognizedPartition = FALSE;
+                PartitionInfo->RecognizedPartition =
IsRecognizedPartition(PartEntry->PartitionType);
                 PartitionInfo->RewritePartition = TRUE;
             }
 
-            PartEntry->PartitionNumber =
(!IsContainerPartition(PartEntry->PartitionType)) ? PartitionNumber : 0;
-            PartEntry->PartitionIndex = Index;
-
             if (!IsContainerPartition(PartEntry->PartitionType))
                 PartitionNumber++;
 
@@ -2215,21 +2354,25 @@ UpdateDiskLayout(
         if (PartEntry->IsPartitioned)
         {
             PartitionInfo = &DiskEntry->LayoutBuffer->PartitionEntry[Index];
+            PartEntry->PartitionIndex = Index;
 
             DPRINT1("Updating logical partition entry %lu\n", Index);
 
+            /* Reset the current partition number only for newly-created partitions */
+            if (PartEntry->New)
+                PartEntry->PartitionNumber = 0;
+
+            PartEntry->OnDiskPartitionNumber = PartitionNumber;
+
             PartitionInfo->StartingOffset.QuadPart =
PartEntry->StartSector.QuadPart * DiskEntry->BytesPerSector;
             PartitionInfo->PartitionLength.QuadPart =
PartEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
             PartitionInfo->HiddenSectors = DiskEntry->SectorAlignment;
-            PartitionInfo->PartitionNumber = PartitionNumber;
+            PartitionInfo->PartitionNumber = PartEntry->PartitionNumber;
             PartitionInfo->PartitionType = PartEntry->PartitionType;
             PartitionInfo->BootIndicator = FALSE;
-            PartitionInfo->RecognizedPartition = FALSE;
+            PartitionInfo->RecognizedPartition =
IsRecognizedPartition(PartEntry->PartitionType);
             PartitionInfo->RewritePartition = TRUE;
 
-            PartEntry->PartitionNumber = PartitionNumber;
-            PartEntry->PartitionIndex = Index;
-
             /* Fill the link entry of the previous partition entry */
             if (LinkInfo != NULL)
             {
@@ -2301,6 +2444,8 @@ UpdateDiskLayout(
         }
     }
 
+    DiskEntry->Dirty = TRUE;
+
 #ifdef DUMP_PARTITION_TABLE
     DumpPartitionTable(DiskEntry);
 #endif
@@ -2367,7 +2512,6 @@ CreatePrimaryPartition(
     ERROR_NUMBER Error;
     PDISKENTRY DiskEntry;
     PPARTENTRY PartEntry;
-    PPARTENTRY NewPartEntry;
 
     DPRINT1("CreatePrimaryPartition(%I64u)\n", SectorCount);
 
@@ -2389,66 +2533,13 @@ CreatePrimaryPartition(
     DiskEntry = List->CurrentDisk;
     PartEntry = List->CurrentPartition;
 
-    DPRINT1("Current partition sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
-
-    if ((AutoCreate != FALSE) ||
-        (AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) - PartEntry->StartSector.QuadPart ==
PartEntry->SectorCount.QuadPart))
-    {
-        DPRINT1("Convert existing partition entry\n");
-
-        /* Convert current entry to 'new (unformatted)' */
-        PartEntry->IsPartitioned = TRUE;
-        PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
-        PartEntry->FormatState = Unformatted;
-        PartEntry->FileSystem  = NULL;
-        PartEntry->AutoCreate = AutoCreate;
-        PartEntry->New = TRUE;
-        PartEntry->BootIndicator = FALSE;
-
-        DPRINT1("First Sector: %I64u\n", PartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", PartEntry->StartSector.QuadPart +
PartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n", PartEntry->SectorCount.QuadPart);
-    }
-    else
-    {
-        DPRINT1("Add new partition entry\n");
-
-        /* Insert and initialize a new partition entry */
-        NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                       HEAP_ZERO_MEMORY,
-                                       sizeof(PARTENTRY));
-        if (NewPartEntry == NULL)
-            return FALSE;
-
-        /* Insert the new entry into the list */
-        InsertTailList(&PartEntry->ListEntry,
-                       &NewPartEntry->ListEntry);
-
-        NewPartEntry->DiskEntry = DiskEntry;
-
-        NewPartEntry->IsPartitioned = TRUE;
-        NewPartEntry->StartSector.QuadPart = PartEntry->StartSector.QuadPart;
-        NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
-                                             NewPartEntry->StartSector.QuadPart;
-        NewPartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
-
-        DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-        NewPartEntry->New = TRUE;
-        NewPartEntry->FormatState = Unformatted;
-        NewPartEntry->FileSystem  = NULL;
-        NewPartEntry->BootIndicator = FALSE;
-
-        PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart;
-        PartEntry->SectorCount.QuadPart -= (PartEntry->StartSector.QuadPart -
NewPartEntry->StartSector.QuadPart);
-    }
+    /* Convert the current entry, or insert and initialize a new partition entry */
+    PartEntry = InitializePartitionEntry(DiskEntry, PartEntry, SectorCount, AutoCreate);
+    if (PartEntry == NULL)
+        return FALSE;
 
     UpdateDiskLayout(DiskEntry);
 
-    DiskEntry->Dirty = TRUE;
-
     AssignDriveLetters(List);
 
     return TRUE;
@@ -2459,33 +2550,28 @@ VOID
 AddLogicalDiskSpace(
     IN PDISKENTRY DiskEntry)
 {
+    ULONGLONG StartSector;
+    ULONGLONG SectorCount;
     PPARTENTRY NewPartEntry;
 
     DPRINT1("AddLogicalDiskSpace()\n");
 
     /* Create a partition entry that represents the empty space in the container
partition */
-    NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                   HEAP_ZERO_MEMORY,
-                                   sizeof(PARTENTRY));
+
+    StartSector = DiskEntry->ExtendedPartition->StartSector.QuadPart +
(ULONGLONG)DiskEntry->SectorAlignment;
+    SectorCount = DiskEntry->ExtendedPartition->SectorCount.QuadPart -
(ULONGLONG)DiskEntry->SectorAlignment;
+
+    NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                           &DiskEntry->LogicalPartListHead,
+                                           StartSector,
+                                           SectorCount,
+                                           TRUE);
     if (NewPartEntry == NULL)
+    {
+        DPRINT1("Failed to create a new empty region for extended partition
space!\n");
         return;
-
-    NewPartEntry->DiskEntry = DiskEntry;
+    }
     NewPartEntry->LogicalPartition = TRUE;
-
-    NewPartEntry->IsPartitioned = FALSE;
-    NewPartEntry->StartSector.QuadPart =
DiskEntry->ExtendedPartition->StartSector.QuadPart +
(ULONGLONG)DiskEntry->SectorAlignment;
-    NewPartEntry->SectorCount.QuadPart =
DiskEntry->ExtendedPartition->SectorCount.QuadPart -
(ULONGLONG)DiskEntry->SectorAlignment;
-
-    DPRINT1("First Sector: %I64u\n", NewPartEntry->StartSector.QuadPart);
-    DPRINT1("Last Sector: %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
-    DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
-
-    NewPartEntry->FormatState = Unformatted;
-    NewPartEntry->FileSystem  = NULL;
-
-    InsertTailList(&DiskEntry->LogicalPartListHead,
-                   &NewPartEntry->ListEntry);
 }
 
 BOOLEAN
@@ -2496,7 +2582,6 @@ CreateExtendedPartition(
     ERROR_NUMBER Error;
     PDISKENTRY DiskEntry;
     PPARTENTRY PartEntry;
-    PPARTENTRY NewPartEntry;
 
     DPRINT1("CreateExtendedPartition(%I64u)\n", SectorCount);
 
@@ -2518,91 +2603,32 @@ CreateExtendedPartition(
     DiskEntry = List->CurrentDisk;
     PartEntry = List->CurrentPartition;
 
-    DPRINT1("Current partition sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
+    /* Convert the current entry, or insert and initialize a new partition entry */
+    PartEntry = InitializePartitionEntry(DiskEntry, PartEntry, SectorCount, FALSE);
+    if (PartEntry == NULL)
+        return FALSE;
 
-    if (AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) - PartEntry->StartSector.QuadPart ==
PartEntry->SectorCount.QuadPart)
+    if (PartEntry->StartSector.QuadPart < 1450560)
     {
-        DPRINT1("Convert existing partition entry\n");
-
-        /* Convert current entry to 'new (unformatted)' */
-        PartEntry->IsPartitioned = TRUE;
-        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;
-
-        if (PartEntry->StartSector.QuadPart < 1450560)
-        {
-            /* Partition starts below the 8.4GB boundary ==> CHS partition */
-            PartEntry->PartitionType = PARTITION_EXTENDED;
-        }
-        else
-        {
-            /* Partition starts above the 8.4GB boundary ==> LBA partition */
-            PartEntry->PartitionType = PARTITION_XINT13_EXTENDED;
-        }
-
-        DiskEntry->ExtendedPartition = PartEntry;
-
-        DPRINT1("First Sector: %I64u\n", PartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", PartEntry->StartSector.QuadPart +
PartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n", PartEntry->SectorCount.QuadPart);
+        /* Partition starts below the 8.4GB boundary ==> CHS partition */
+        PartEntry->PartitionType = PARTITION_EXTENDED;
     }
     else
     {
-        DPRINT1("Add new partition entry\n");
-
-        /* Insert and initialize a new partition entry */
-        NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                       HEAP_ZERO_MEMORY,
-                                       sizeof(PARTENTRY));
-        if (NewPartEntry == NULL)
-            return FALSE;
-
-        /* Insert the new entry into the list */
-        InsertTailList(&PartEntry->ListEntry,
-                       &NewPartEntry->ListEntry);
-
-        NewPartEntry->DiskEntry = DiskEntry;
-
-        NewPartEntry->IsPartitioned = TRUE;
-        NewPartEntry->StartSector.QuadPart = PartEntry->StartSector.QuadPart;
-        NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
-                                             NewPartEntry->StartSector.QuadPart;
-
-        NewPartEntry->New = FALSE;
-        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)
-        {
-            /* Partition starts below the 8.4GB boundary ==> CHS partition */
-            NewPartEntry->PartitionType = PARTITION_EXTENDED;
-        }
-        else
-        {
-            /* Partition starts above the 8.4GB boundary ==> LBA partition */
-            NewPartEntry->PartitionType = PARTITION_XINT13_EXTENDED;
-        }
-
-        DiskEntry->ExtendedPartition = NewPartEntry;
+        /* Partition starts above the 8.4GB boundary ==> LBA partition */
+        PartEntry->PartitionType = PARTITION_XINT13_EXTENDED;
+    }
 
-        PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart;
-        PartEntry->SectorCount.QuadPart -= (PartEntry->StartSector.QuadPart -
NewPartEntry->StartSector.QuadPart);
+    // FIXME? Possibly to make GetNextUnformattedPartition work (i.e. skip the extended
partition container)
+    PartEntry->New = FALSE;
+    PartEntry->FormatState = Formatted;
 
-        DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-    }
+    DiskEntry->ExtendedPartition = PartEntry;
 
     AddLogicalDiskSpace(DiskEntry);
 
     UpdateDiskLayout(DiskEntry);
 
-    DiskEntry->Dirty = TRUE;
-
     AssignDriveLetters(List);
 
     return TRUE;
@@ -2617,7 +2643,6 @@ CreateLogicalPartition(
     ERROR_NUMBER Error;
     PDISKENTRY DiskEntry;
     PPARTENTRY PartEntry;
-    PPARTENTRY NewPartEntry;
 
     DPRINT1("CreateLogicalPartition(%I64u)\n", SectorCount);
 
@@ -2639,68 +2664,15 @@ CreateLogicalPartition(
     DiskEntry = List->CurrentDisk;
     PartEntry = List->CurrentPartition;
 
-    DPRINT1("Current partition sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
-
-    if ((AutoCreate != FALSE) ||
-        (AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) - PartEntry->StartSector.QuadPart ==
PartEntry->SectorCount.QuadPart))
-    {
-        DPRINT1("Convert existing partition entry\n");
-
-        /* Convert current entry to 'new (unformatted)' */
-        PartEntry->IsPartitioned = TRUE;
-        PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
-        PartEntry->FormatState = Unformatted;
-        PartEntry->FileSystem  = NULL;
-        PartEntry->AutoCreate = FALSE;
-        PartEntry->New = TRUE;
-        PartEntry->BootIndicator = FALSE;
-        PartEntry->LogicalPartition = TRUE;
-
-        DPRINT1("First Sector: %I64u\n", PartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", PartEntry->StartSector.QuadPart +
PartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n", PartEntry->SectorCount.QuadPart);
-    }
-    else
-    {
-        DPRINT1("Add new partition entry\n");
-
-        /* Insert and initialize a new partition entry */
-        NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                       HEAP_ZERO_MEMORY,
-                                       sizeof(PARTENTRY));
-        if (NewPartEntry == NULL)
-            return FALSE;
-
-        /* Insert the new entry into the list */
-        InsertTailList(&PartEntry->ListEntry,
-                       &NewPartEntry->ListEntry);
-
-        NewPartEntry->DiskEntry = DiskEntry;
-
-        NewPartEntry->IsPartitioned = TRUE;
-        NewPartEntry->StartSector.QuadPart = PartEntry->StartSector.QuadPart;
-        NewPartEntry->SectorCount.QuadPart =
AlignDown(NewPartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
-                                             NewPartEntry->StartSector.QuadPart;
-        NewPartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
-
-        DPRINT1("First Sector: %I64u\n",
NewPartEntry->StartSector.QuadPart);
-        DPRINT1("Last Sector: %I64u\n", NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart - 1);
-        DPRINT1("Total Sectors: %I64u\n",
NewPartEntry->SectorCount.QuadPart);
-
-        NewPartEntry->New = TRUE;
-        NewPartEntry->FormatState = Unformatted;
-        NewPartEntry->FileSystem  = NULL;
-        NewPartEntry->BootIndicator = FALSE;
-        NewPartEntry->LogicalPartition = TRUE;
+    /* Convert the current entry, or insert and initialize a new partition entry */
+    PartEntry = InitializePartitionEntry(DiskEntry, PartEntry, SectorCount, AutoCreate);
+    if (PartEntry == NULL)
+        return FALSE;
 
-        PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart +
NewPartEntry->SectorCount.QuadPart;
-        PartEntry->SectorCount.QuadPart -= (PartEntry->StartSector.QuadPart -
NewPartEntry->StartSector.QuadPart);
-    }
+    PartEntry->LogicalPartition = TRUE;
 
     UpdateDiskLayout(DiskEntry);
 
-    DiskEntry->Dirty = TRUE;
-
     AssignDriveLetters(List);
 
     return TRUE;
@@ -2924,12 +2896,13 @@ DeleteCurrentPartition(
         PartEntry->FormatState = Unformatted;
         PartEntry->FileSystem  = NULL;
         PartEntry->DriveLetter = 0;
+        PartEntry->OnDiskPartitionNumber = 0;
+        PartEntry->PartitionNumber = 0;
+        // PartEntry->PartitionIndex = 0;
     }
 
     UpdateDiskLayout(DiskEntry);
 
-    DiskEntry->Dirty = TRUE;
-
     AssignDriveLetters(List);
 }
 
@@ -3174,13 +3147,17 @@ WritePartitions(
     IN PPARTLIST List,
     IN PDISKENTRY DiskEntry)
 {
-    WCHAR DstPath[MAX_PATH];
+    NTSTATUS Status;
     OBJECT_ATTRIBUTES ObjectAttributes;
-    IO_STATUS_BLOCK Iosb;
     UNICODE_STRING Name;
+    HANDLE FileHandle;
+    IO_STATUS_BLOCK Iosb;
     ULONG BufferSize;
-    HANDLE FileHandle = NULL;
-    NTSTATUS Status;
+    PPARTITION_INFORMATION PartitionInfo;
+    ULONG PartitionCount;
+    PLIST_ENTRY ListEntry;
+    PPARTENTRY PartEntry;
+    WCHAR DstPath[MAX_PATH];
 
     DPRINT("WritePartitions() Disk: %lu\n", DiskEntry->DiskNumber);
 
@@ -3217,8 +3194,12 @@ WritePartitions(
     // For this we must ask the user which format to use.
     //
 
+    /* Save the original partition count to be restored later (see comment below) */
+    PartitionCount = DiskEntry->LayoutBuffer->PartitionCount;
+
+    /* Set the new disk layout and retrieve its updated version with possibly modified
partition numbers */
     BufferSize = sizeof(DRIVE_LAYOUT_INFORMATION) +
-                 ((DiskEntry->LayoutBuffer->PartitionCount - 1) *
sizeof(PARTITION_INFORMATION));
+                 ((PartitionCount - 1) * sizeof(PARTITION_INFORMATION));
     Status = NtDeviceIoControlFile(FileHandle,
                                    NULL,
                                    NULL,
@@ -3227,15 +3208,61 @@ WritePartitions(
                                    IOCTL_DISK_SET_DRIVE_LAYOUT,
                                    DiskEntry->LayoutBuffer,
                                    BufferSize,
-                                   NULL,
-                                   0);
+                                   DiskEntry->LayoutBuffer,
+                                   BufferSize);
+    NtClose(FileHandle);
+
+    /*
+     * IOCTL_DISK_SET_DRIVE_LAYOUT calls IoWritePartitionTable(), which converts
+     * DiskEntry->LayoutBuffer->PartitionCount into a partition *table* count,
+     * where such a table is expected to enumerate up to 4 partitions:
+     * partition *table* count == ROUND_UP(PartitionCount, 4) / 4 .
+     * Due to this we need to restore the original PartitionCount number.
+     */
+    DiskEntry->LayoutBuffer->PartitionCount = PartitionCount;
+
+    /* Check whether the IOCTL_DISK_SET_DRIVE_LAYOUT call succeeded */
     if (!NT_SUCCESS(Status))
     {
         DPRINT1("IOCTL_DISK_SET_DRIVE_LAYOUT failed (Status 0x%08lx)\n",
Status);
+        return Status;
     }
 
-    if (FileHandle != NULL)
-        NtClose(FileHandle);
+#ifdef DUMP_PARTITION_TABLE
+    DumpPartitionTable(DiskEntry);
+#endif
+
+    /* Update the partition numbers */
+
+    /* Update the primary partition table */
+    ListEntry = DiskEntry->PrimaryPartListHead.Flink;
+    while (ListEntry != &DiskEntry->PrimaryPartListHead)
+    {
+        PartEntry = CONTAINING_RECORD(ListEntry, PARTENTRY, ListEntry);
+
+        if (PartEntry->IsPartitioned)
+        {
+            PartitionInfo =
&DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex];
+            PartEntry->PartitionNumber = PartitionInfo->PartitionNumber;
+        }
+
+        ListEntry = ListEntry->Flink;
+    }
+
+    /* Update the logical partition table */
+    ListEntry = DiskEntry->LogicalPartListHead.Flink;
+    while (ListEntry != &DiskEntry->LogicalPartListHead)
+    {
+        PartEntry = CONTAINING_RECORD(ListEntry, PARTENTRY, ListEntry);
+
+        if (PartEntry->IsPartitioned)
+        {
+            PartitionInfo =
&DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex];
+            PartEntry->PartitionNumber = PartitionInfo->PartitionNumber;
+        }
+
+        ListEntry = ListEntry->Flink;
+    }
 
     //
     // NOTE: Originally (see r40437), we used to install here also a new MBR
@@ -3247,6 +3274,8 @@ WritePartitions(
     // DiskEntry->NoMbr was TRUE (instead of NewDisk).
     //
 
+    // DiskEntry->Dirty = FALSE;
+
     return Status;
 }
 
@@ -3419,6 +3448,7 @@ SetPartitionType(
 
     DiskEntry->Dirty = TRUE;
    
DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].PartitionType
= PartitionType;
+   
DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RecognizedPartition
= IsRecognizedPartition(PartitionType);
    
DiskEntry->LayoutBuffer->PartitionEntry[PartEntry->PartitionIndex].RewritePartition
= TRUE;
 }
 
diff --git a/base/setup/lib/utils/partlist.h b/base/setup/lib/utils/partlist.h
index f2f856cda2..8e2c635bce 100644
--- a/base/setup/lib/utils/partlist.h
+++ b/base/setup/lib/utils/partlist.h
@@ -46,8 +46,9 @@ typedef struct _PARTENTRY
     BOOLEAN BootIndicator;
     UCHAR PartitionType;
     ULONG HiddenSectors;
-    ULONG PartitionNumber;  /* Enumerated partition number (primary partitions first --
excluding the extended partition container --, then the logical partitions) */
-    ULONG PartitionIndex;   /* Index in the LayoutBuffer->PartitionEntry[] cached
array of the corresponding DiskEntry */
+    ULONG OnDiskPartitionNumber; /* Enumerated partition number (primary partitions
first, excluding the extended partition container, then the logical partitions) */
+    ULONG PartitionNumber;       /* Current partition number, only valid for the
currently running NTOS instance */
+    ULONG PartitionIndex;        /* Index in the LayoutBuffer->PartitionEntry[] cached
array of the corresponding DiskEntry */
 
     WCHAR DriveLetter;
     WCHAR VolumeLabel[20];
@@ -116,8 +117,8 @@ typedef struct _DISKENTRY
     /* Has the partition list been modified? */
     BOOLEAN Dirty;
 
-    BOOLEAN NewDisk;
-    BOOLEAN NoMbr; /* MBR is absent */  // See r40437
+    BOOLEAN NewDisk; /* If TRUE, the disk is uninitialized */
+    BOOLEAN NoMbr;   /* If TRUE, the MBR is absent */  // See r40437
 
     UNICODE_STRING DriverName;
 
@@ -127,11 +128,11 @@ typedef struct _DISKENTRY
     // 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; /* List of primary partitions */
+    LIST_ENTRY LogicalPartListHead; /* List of logical partitions (Valid only for
MBR-partitioned disks) */
 
-    LIST_ENTRY PrimaryPartListHead;
-    LIST_ENTRY LogicalPartListHead;
+    /* Pointer to the unique extended partition on this disk (Valid only for
MBR-partitioned disks) */
+    PPARTENTRY ExtendedPartition;
 
 } DISKENTRY, *PDISKENTRY;