[ros-diffs] [reactos] 01/01: [SETUPLIB][USETUP] Some cleanup for partition code.

[Hermès Bélusca-Maïto]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=b7ad4a2298edc0c232e00…

commit b7ad4a2298edc0c232e001c1662205dad022578f
Author:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
AuthorDate: Thu Dec 7 23:29:28 2023 +0100
Commit:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
CommitDate: Tue Feb 20 15:52:37 2024 +0100

    [SETUPLIB][USETUP] Some cleanup for partition code.
    
    - Make the Create*Partition helpers take a size in bytes, not in sectors.
    
      This allows them to be easier to use by the caller, alleviating the
      need for making the size conversion into sectors. Instead it is done
      internally by the helpers.
    
    - Introduce helper macros to easily retrieve the size of a partition
      entry or a disk in bytes, from their internal representation in number
      of sectors.
    
    - The 'AutoCreate' variable being USETUP-specific, remove it from the
      PARTENTRY structure and use instead a flag set into the 'New' member.
    
    - Rename IsDiskSizeValid to IsPartitionLargeEnough, to better describe
      what the function is for.
---
 base/setup/lib/utils/osdetect.c |   6 +-
 base/setup/lib/utils/partlist.c | 104 ++++++++++++++++---------------
 base/setup/lib/utils/partlist.h |  18 ++++--
 base/setup/usetup/partlist.c    |   4 +-
 base/setup/usetup/usetup.c      | 134 ++++++++++++++++++++--------------------
 5 files changed, 139 insertions(+), 127 deletions(-)

diff --git a/base/setup/lib/utils/osdetect.c b/base/setup/lib/utils/osdetect.c
index 0ee246c60b1..cc45fa907c2 100644
--- a/base/setup/lib/utils/osdetect.c
+++ b/base/setup/lib/utils/osdetect.c
@@ -806,12 +806,11 @@ CreateNTOSInstallationsList(
 
             ASSERT(PartEntry->DiskEntry == DiskEntry);
 
-            DPRINT("   Primary Partition #%d, index %d - Type 0x%02x, IsLogical =
%s, IsPartitioned = %s, IsNew = %s, AutoCreate = %s, FormatState = %lu -- Should I check
it? %s\n",
+            DPRINT("   Primary Partition #%d, index %d - Type 0x%02x, IsLogical =
%s, IsPartitioned = %s, IsNew = %s, FormatState = %lu -- Should I check it? %s\n",
                    PartEntry->PartitionNumber, PartEntry->PartitionIndex,
                    PartEntry->PartitionType, PartEntry->LogicalPartition ?
"TRUE" : "FALSE",
                    PartEntry->IsPartitioned ? "TRUE" : "FALSE",
                    PartEntry->New ? "Yes" : "No",
-                   PartEntry->AutoCreate ? "Yes" : "No",
                    PartEntry->FormatState,
                    ShouldICheckThisPartition(PartEntry) ? "YES!" :
"NO!");
 
@@ -828,12 +827,11 @@ CreateNTOSInstallationsList(
 
             ASSERT(PartEntry->DiskEntry == DiskEntry);
 
-            DPRINT("   Logical Partition #%d, index %d - Type 0x%02x, IsLogical =
%s, IsPartitioned = %s, IsNew = %s, AutoCreate = %s, FormatState = %lu -- Should I check
it? %s\n",
+            DPRINT("   Logical Partition #%d, index %d - Type 0x%02x, IsLogical =
%s, IsPartitioned = %s, IsNew = %s, FormatState = %lu -- Should I check it? %s\n",
                    PartEntry->PartitionNumber, PartEntry->PartitionIndex,
                    PartEntry->PartitionType, PartEntry->LogicalPartition ?
"TRUE" : "FALSE",
                    PartEntry->IsPartitioned ? "TRUE" : "FALSE",
                    PartEntry->New ? "Yes" : "No",
-                   PartEntry->AutoCreate ? "Yes" : "No",
                    PartEntry->FormatState,
                    ShouldICheckThisPartition(PartEntry) ? "YES!" :
"NO!");
 
diff --git a/base/setup/lib/utils/partlist.c b/base/setup/lib/utils/partlist.c
index 49c15e9ffe2..6bb16fed9d4 100644
--- a/base/setup/lib/utils/partlist.c
+++ b/base/setup/lib/utils/partlist.c
@@ -552,7 +552,7 @@ IsSuperFloppy(
     }
 
     /* The partition lengths should agree */
-    PartitionLengthEstimate = DiskEntry->SectorCount.QuadPart *
DiskEntry->BytesPerSector;
+    PartitionLengthEstimate = GetDiskSizeInBytes(DiskEntry);
     if (PartitionInfo->PartitionLength.QuadPart != PartitionLengthEstimate)
     {
         DPRINT1("PartitionLength = %I64u is different from PartitionLengthEstimate =
%I64u\n",
@@ -676,26 +676,46 @@ CreateInsertBlankRegion(
 static
 BOOLEAN
 InitializePartitionEntry(
-    IN OUT PPARTENTRY PartEntry,
-    IN ULONGLONG SectorCount,
-    IN BOOLEAN AutoCreate)
+    _Inout_ PPARTENTRY PartEntry,
+    _In_opt_ ULONGLONG SizeBytes)
 {
     PDISKENTRY DiskEntry = PartEntry->DiskEntry;
+    ULONGLONG SectorCount;
+
+    DPRINT1("Current entry sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
 
-    DPRINT1("Current partition sector count: %I64u\n",
PartEntry->SectorCount.QuadPart);
+    /* The entry must not be already partitioned and not be void */
+    ASSERT(!PartEntry->IsPartitioned);
+    ASSERT(PartEntry->SectorCount.QuadPart);
+
+    /* Convert the size in bytes to sector count. SizeBytes being
+     * zero means the caller wants to use all the empty space. */
+    if ((SizeBytes == 0) || (SizeBytes == GetPartEntrySizeInBytes(PartEntry)))
+    {
+        /* Use all of the unpartitioned disk space */
+        SectorCount = PartEntry->SectorCount.QuadPart;
+    }
+    else
+    {
+        SectorCount = SizeBytes / DiskEntry->BytesPerSector;
+        if (SectorCount == 0)
+        {
+            /* SizeBytes was certainly less than the minimal size, so fail */
+            DPRINT1("Partition size %I64u too small\n", SizeBytes);
+            return FALSE;
+        }
+    }
+    DPRINT1("    New sector count: %I64u\n", SectorCount);
 
-    /* Fail if we try to initialize this partition entry with more sectors than what it
actually contains */
+    /* Fail if we request more sectors than what the entry actually contains */
     if (SectorCount > PartEntry->SectorCount.QuadPart)
         return FALSE;
 
-    /* Fail if the partition is already in use */
-    ASSERT(!PartEntry->IsPartitioned);
-
-    if ((AutoCreate != FALSE) ||
+    if ((SectorCount == 0) ||
         (AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment) -
                    PartEntry->StartSector.QuadPart ==
PartEntry->SectorCount.QuadPart))
     {
-        PartEntry->AutoCreate = AutoCreate;
+        /* Reuse the whole current entry */
     }
     else
     {
@@ -703,7 +723,8 @@ InitializePartitionEntry(
         ULONGLONG SectorCount2;
         PPARTENTRY NewPartEntry;
 
-        /* Create a partition entry that represents the remaining space after the
partition to be initialized */
+        /* Create a partition entry that represents the remaining space
+         * after the partition to be initialized */
 
         StartSector = AlignDown(PartEntry->StartSector.QuadPart + SectorCount,
DiskEntry->SectorAlignment);
         SectorCount2 = PartEntry->StartSector.QuadPart +
PartEntry->SectorCount.QuadPart - StartSector;
@@ -735,7 +756,6 @@ InitializePartitionEntry(
 
     PartEntry->FormatState = Unformatted;
     PartEntry->FileSystem[0] = L'\0';
-    // PartEntry->AutoCreate = AutoCreate;
     PartEntry->BootIndicator = FALSE;
 
     DPRINT1("First Sector : %I64u\n", PartEntry->StartSector.QuadPart);
@@ -2390,37 +2410,24 @@ GetPrevPartition(
     return NULL;
 }
 
-// static
-FORCEINLINE
+static inline
 BOOLEAN
 IsEmptyLayoutEntry(
-    IN PPARTITION_INFORMATION PartitionInfo)
+    _In_ PPARTITION_INFORMATION PartitionInfo)
 {
-    if (PartitionInfo->StartingOffset.QuadPart == 0 &&
-        PartitionInfo->PartitionLength.QuadPart == 0)
-    {
-        return TRUE;
-    }
-
-    return FALSE;
+    return (PartitionInfo->StartingOffset.QuadPart == 0 &&
+            PartitionInfo->PartitionLength.QuadPart == 0);
 }
 
-// static
-FORCEINLINE
+static inline
 BOOLEAN
 IsSamePrimaryLayoutEntry(
-    IN PPARTITION_INFORMATION PartitionInfo,
-    IN PDISKENTRY DiskEntry,
-    IN PPARTENTRY PartEntry)
+    _In_ PPARTITION_INFORMATION PartitionInfo,
+    _In_ PPARTENTRY PartEntry)
 {
-    if (PartitionInfo->StartingOffset.QuadPart == PartEntry->StartSector.QuadPart *
DiskEntry->BytesPerSector &&
-        PartitionInfo->PartitionLength.QuadPart == PartEntry->SectorCount.QuadPart
* DiskEntry->BytesPerSector)
+    return ((PartitionInfo->StartingOffset.QuadPart ==
GetPartEntryOffsetInBytes(PartEntry)) &&
+            (PartitionInfo->PartitionLength.QuadPart ==
GetPartEntrySizeInBytes(PartEntry)));
 //        PartitionInfo->PartitionType == PartEntry->PartitionType
-    {
-        return TRUE;
-    }
-
-    return FALSE;
 }
 
 static
@@ -2578,12 +2585,12 @@ UpdateDiskLayout(
 
             PartEntry->OnDiskPartitionNumber =
(!IsContainerPartition(PartEntry->PartitionType) ? PartitionNumber : 0);
 
-            if (!IsSamePrimaryLayoutEntry(PartitionInfo, DiskEntry, PartEntry))
+            if (!IsSamePrimaryLayoutEntry(PartitionInfo, PartEntry))
             {
                 DPRINT1("Updating primary partition entry %lu\n", Index);
 
-                PartitionInfo->StartingOffset.QuadPart =
PartEntry->StartSector.QuadPart * DiskEntry->BytesPerSector;
-                PartitionInfo->PartitionLength.QuadPart =
PartEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
+                PartitionInfo->StartingOffset.QuadPart =
GetPartEntryOffsetInBytes(PartEntry);
+                PartitionInfo->PartitionLength.QuadPart =
GetPartEntrySizeInBytes(PartEntry);
                 PartitionInfo->HiddenSectors = PartEntry->StartSector.LowPart;
                 PartitionInfo->PartitionNumber = PartEntry->PartitionNumber;
                 PartitionInfo->PartitionType = PartEntry->PartitionType;
@@ -2624,8 +2631,8 @@ UpdateDiskLayout(
 
             DPRINT1("Updating logical partition entry %lu\n", Index);
 
-            PartitionInfo->StartingOffset.QuadPart =
PartEntry->StartSector.QuadPart * DiskEntry->BytesPerSector;
-            PartitionInfo->PartitionLength.QuadPart =
PartEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
+            PartitionInfo->StartingOffset.QuadPart =
GetPartEntryOffsetInBytes(PartEntry);
+            PartitionInfo->PartitionLength.QuadPart =
GetPartEntrySizeInBytes(PartEntry);
             PartitionInfo->HiddenSectors = DiskEntry->SectorAlignment;
             PartitionInfo->PartitionNumber = PartEntry->PartitionNumber;
             PartitionInfo->PartitionType = PartEntry->PartitionType;
@@ -2862,12 +2869,11 @@ BOOLEAN
 CreatePartition(
     _In_ PPARTLIST List,
     _Inout_ PPARTENTRY PartEntry,
-    _In_ ULONGLONG SectorCount,
-    _In_ BOOLEAN AutoCreate)
+    _In_opt_ ULONGLONG SizeBytes)
 {
     ERROR_NUMBER Error;
 
-    DPRINT1("CreatePartition(%I64u)\n", SectorCount);
+    DPRINT1("CreatePartition(%I64u bytes)\n", SizeBytes);
 
     if (List == NULL || PartEntry == NULL ||
         PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned)
@@ -2883,7 +2889,7 @@ CreatePartition(
     }
 
     /* Initialize the partition entry, inserting a new blank region if needed */
-    if (!InitializePartitionEntry(PartEntry, SectorCount, AutoCreate))
+    if (!InitializePartitionEntry(PartEntry, SizeBytes))
         return FALSE;
 
     UpdateDiskLayout(PartEntry->DiskEntry);
@@ -2924,11 +2930,11 @@ BOOLEAN
 CreateExtendedPartition(
     _In_ PPARTLIST List,
     _Inout_ PPARTENTRY PartEntry,
-    _In_ ULONGLONG SectorCount)
+    _In_opt_ ULONGLONG SizeBytes)
 {
     ERROR_NUMBER Error;
 
-    DPRINT1("CreateExtendedPartition(%I64u)\n", SectorCount);
+    DPRINT1("CreateExtendedPartition(%I64u bytes)\n", SizeBytes);
 
     if (List == NULL || PartEntry == NULL ||
         PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned)
@@ -2944,7 +2950,7 @@ CreateExtendedPartition(
     }
 
     /* Initialize the partition entry, inserting a new blank region if needed */
-    if (!InitializePartitionEntry(PartEntry, SectorCount, FALSE))
+    if (!InitializePartitionEntry(PartEntry, SizeBytes))
         return FALSE;
 
     ASSERT(PartEntry->LogicalPartition == FALSE);
@@ -3933,7 +3939,7 @@ SetMountedDeviceValues(
                 /* Assign a "\DosDevices\#:" mount point to this partition */
                 if (PartEntry->DriveLetter)
                 {
-                    StartingOffset.QuadPart = PartEntry->StartSector.QuadPart *
DiskEntry->BytesPerSector;
+                    StartingOffset.QuadPart = GetPartEntryOffsetInBytes(PartEntry);
                     if (!SetMountedDeviceValue(PartEntry->DriveLetter,
                                               
DiskEntry->LayoutBuffer->Signature,
                                                StartingOffset))
@@ -3956,7 +3962,7 @@ SetMountedDeviceValues(
                 /* Assign a "\DosDevices\#:" mount point to this partition */
                 if (PartEntry->DriveLetter)
                 {
-                    StartingOffset.QuadPart = PartEntry->StartSector.QuadPart *
DiskEntry->BytesPerSector;
+                    StartingOffset.QuadPart = GetPartEntryOffsetInBytes(PartEntry);
                     if (!SetMountedDeviceValue(PartEntry->DriveLetter,
                                               
DiskEntry->LayoutBuffer->Signature,
                                                StartingOffset))
diff --git a/base/setup/lib/utils/partlist.h b/base/setup/lib/utils/partlist.h
index c59b5e1f4b7..d5b20615455 100644
--- a/base/setup/lib/utils/partlist.h
+++ b/base/setup/lib/utils/partlist.h
@@ -70,9 +70,6 @@ typedef struct _PARTENTRY
     /* Partition is new, table does not exist on disk yet */
     BOOLEAN New;
 
-    /* Partition was created automatically */
-    BOOLEAN AutoCreate;
-
     /* Partition must be checked */
     BOOLEAN NeedsCheck;
 
@@ -227,6 +224,16 @@ RoundingDivide(
    IN ULONGLONG Divisor);
 
 
+#define GetPartEntryOffsetInBytes(PartEntry) \
+    ((PartEntry)->StartSector.QuadPart *
(PartEntry)->DiskEntry->BytesPerSector)
+
+#define GetPartEntrySizeInBytes(PartEntry) \
+    ((PartEntry)->SectorCount.QuadPart *
(PartEntry)->DiskEntry->BytesPerSector)
+
+#define GetDiskSizeInBytes(DiskEntry) \
+    ((DiskEntry)->SectorCount.QuadPart * (DiskEntry)->BytesPerSector)
+
+
 BOOLEAN
 IsSuperFloppy(
     IN PDISKENTRY DiskEntry);
@@ -306,14 +313,13 @@ BOOLEAN
 CreatePartition(
     _In_ PPARTLIST List,
     _Inout_ PPARTENTRY PartEntry,
-    _In_ ULONGLONG SectorCount,
-    _In_ BOOLEAN AutoCreate);
+    _In_opt_ ULONGLONG SizeBytes);
 
 BOOLEAN
 CreateExtendedPartition(
     _In_ PPARTLIST List,
     _Inout_ PPARTENTRY PartEntry,
-    _In_ ULONGLONG SectorCount);
+    _In_opt_ ULONGLONG SizeBytes);
 
 NTSTATUS
 DismountVolume(
diff --git a/base/setup/usetup/partlist.c b/base/setup/usetup/partlist.c
index 5feaf446529..72ae328cbde 100644
--- a/base/setup/usetup/partlist.c
+++ b/base/setup/usetup/partlist.c
@@ -156,7 +156,7 @@ PartitionDescription(
     PCSTR Unit;
 
     /* Get the partition size */
-    PartSize = PartEntry->SectorCount.QuadPart *
PartEntry->DiskEntry->BytesPerSector;
+    PartSize = GetPartEntrySizeInBytes(PartEntry);
     PrettifySize2(&PartSize, &Unit);
 
     if (PartEntry->IsPartitioned == FALSE)
@@ -307,7 +307,7 @@ DiskDescription(
     PCSTR Unit;
 
     /* Get the disk size */
-    DiskSize = DiskEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector;
+    DiskSize = GetDiskSizeInBytes(DiskEntry);
     PrettifySize1(&DiskSize, &Unit);
 
     //
diff --git a/base/setup/usetup/usetup.c b/base/setup/usetup/usetup.c
index 61fae743780..59593f38b59 100644
--- a/base/setup/usetup/usetup.c
+++ b/base/setup/usetup/usetup.c
@@ -79,6 +79,9 @@ static enum {
     PartTypeExtended // MBR-disk container
 } PartCreateType = PartTypeData;
 
+/* Flag set in PARTENTRY::New when a partition is created automatically */
+#define PARTITION_NEW_AUTOCREATE    0x80
+
 /* List of supported file systems for the partition to be formatted */
 static PFILE_SYSTEM_LIST FileSystemList = NULL;
 
@@ -1503,18 +1506,18 @@ LayoutSettingsPage(PINPUT_RECORD Ir)
 }
 
 
-static BOOL
-IsDiskSizeValid(PPARTENTRY PartEntry)
+static BOOLEAN
+IsPartitionLargeEnough(
+    _In_ PPARTENTRY PartEntry)
 {
-    ULONGLONG size;
+    /* Retrieve the maximum size in MB (rounded up) */
+    ULONGLONG PartSize = RoundingDivide(GetPartEntrySizeInBytes(PartEntry), MB);
 
-    size = PartEntry->SectorCount.QuadPart *
PartEntry->DiskEntry->BytesPerSector;
-    size = (size + (512 * KB)) / MB;  /* in MBytes */
-
-    if (size < USetupData.RequiredPartitionDiskSpace)
+    if (PartSize < USetupData.RequiredPartitionDiskSpace)
     {
         /* Partition is too small so ask for another one */
-        DPRINT1("Partition is too small (size: %I64u MB), required disk space is %lu
MB\n", size, USetupData.RequiredPartitionDiskSpace);
+        DPRINT1("Partition is too small (size: %I64u MB), required disk space is %lu
MB\n",
+                PartSize, USetupData.RequiredPartitionDiskSpace);
         return FALSE;
     }
     else
@@ -1608,13 +1611,15 @@ SelectPartitionPage(PINPUT_RECORD Ir)
                 ASSERT(CurrentPartition != NULL);
                 ASSERT(!IsContainerPartition(CurrentPartition->PartitionType));
 
+                /* Automatically create the partition on the whole empty space;
+                 * it will be formatted later with default parameters */
                 CreatePartition(PartitionList,
                                 CurrentPartition,
-                                CurrentPartition->SectorCount.QuadPart,
-                                TRUE);
+                                0ULL);
+                CurrentPartition->New |= PARTITION_NEW_AUTOCREATE;
 
 // FIXME?? Aren't we going to enter an infinite loop, if this test fails??
-                if (!IsDiskSizeValid(CurrentPartition))
+                if (!IsPartitionLargeEnough(CurrentPartition))
                 {
                     MUIDisplayError(ERROR_INSUFFICIENT_PARTITION_SIZE, Ir,
POPUP_WAIT_ANY_KEY,
                                     USetupData.RequiredPartitionDiskSpace);
@@ -1632,7 +1637,7 @@ SelectPartitionPage(PINPUT_RECORD Ir)
             DrawPartitionList(&ListUi); // FIXME: Doesn't make much sense...
 
 // FIXME?? Aren't we going to enter an infinite loop, if this test fails??
-            if (!IsDiskSizeValid(InstallPartition))
+            if (!IsPartitionLargeEnough(InstallPartition))
             {
                 MUIDisplayError(ERROR_INSUFFICIENT_PARTITION_SIZE, Ir,
POPUP_WAIT_ANY_KEY,
                                 USetupData.RequiredPartitionDiskSpace);
@@ -1737,13 +1742,15 @@ SelectPartitionPage(PINPUT_RECORD Ir)
                     return SELECT_PARTITION_PAGE;
                 }
 
+                /* Automatically create the partition on the whole empty space;
+                 * it will be formatted later with default parameters */
                 CreatePartition(PartitionList,
                                 CurrentPartition,
-                                0ULL,
-                                TRUE);
+                                0ULL);
+                CurrentPartition->New |= PARTITION_NEW_AUTOCREATE;
             }
 
-            if (!IsDiskSizeValid(CurrentPartition))
+            if (!IsPartitionLargeEnough(CurrentPartition))
             {
                 MUIDisplayError(ERROR_INSUFFICIENT_PARTITION_SIZE, Ir,
POPUP_WAIT_ANY_KEY,
                                 USetupData.RequiredPartitionDiskSpace);
@@ -2040,11 +2047,9 @@ CreatePartitionPage(PINPUT_RECORD Ir)
     PPARTENTRY PartEntry;
     PDISKENTRY DiskEntry;
     ULONG uID;
-    BOOLEAN Quit;
-    BOOLEAN Cancel;
     ULONG MaxSize;
-    ULONGLONG PartSize;
-    ULONGLONG SectorCount;
+    ULONGLONG MaxPartSize, PartSize;
+    BOOLEAN Quit, Cancel;
     WCHAR InputBuffer[50];
     CHAR LineBuffer[100];
 
@@ -2078,15 +2083,17 @@ CreatePartitionPage(PINPUT_RECORD Ir)
 
     CONSOLE_SetStatusText(MUIGetString(STRING_CREATEPARTITION));
 
+    MaxPartSize = GetPartEntrySizeInBytes(PartEntry);
+
     while (TRUE)
     {
-        MaxSize = (PartEntry->SectorCount.QuadPart * DiskEntry->BytesPerSector) /
MB;  /* in MBytes (rounded) */
-        if (MaxSize > PARTITION_MAXSIZE)
-            MaxSize = PARTITION_MAXSIZE;
+        /* Retrieve the maximum size in MB (rounded up)
+         * and cap it with what the user can enter */
+        MaxSize = (ULONG)RoundingDivide(MaxPartSize, MB);
+        MaxSize = min(MaxSize, PARTITION_MAXSIZE);
 
-        ShowPartitionSizeInputBox(12, 14, xScreen - 12, 17, /* left, top, right, bottom
*/
+        ShowPartitionSizeInputBox(12, 14, xScreen - 12, 17,
                                   MaxSize, InputBuffer, &Quit, &Cancel);
-
         if (Quit)
         {
             if (ConfirmQuit(Ir))
@@ -2097,50 +2104,41 @@ CreatePartitionPage(PINPUT_RECORD Ir)
         {
             return SELECT_PARTITION_PAGE;
         }
-        else
-        {
-            PartSize = _wcstoui64(InputBuffer, NULL, 10);
 
-            /* Retry if too small or too large */
-            if (PartSize < 1)
-                continue;
-            if (PartSize > MaxSize)
-                continue;
-
-            /* Convert to bytes */
-            if (PartSize == MaxSize)
-            {
-                /* Use all of the unpartitioned disk space */
-                SectorCount = PartEntry->SectorCount.QuadPart;
-            }
-            else
-            {
-                /* Calculate the sector count from the size in MB */
-                SectorCount = PartSize * MB / DiskEntry->BytesPerSector;
+        PartSize = _wcstoui64(InputBuffer, NULL, 10);
 
-                /* But never get larger than the unpartitioned disk space */
-                if (SectorCount > PartEntry->SectorCount.QuadPart)
-                    SectorCount = PartEntry->SectorCount.QuadPart;
-            }
+        /* Retry if too small or too large */
+        if ((PartSize < 1) || (PartSize > MaxSize))
+            continue;
 
-            DPRINT("Partition size: %I64u bytes\n", PartSize);
+        /*
+         * If the input size, given in MB, specifies the maximum partition
+         * size, it may slightly under- or over-estimate it due to rounding
+         * error. In this case, use all of the unpartitioned disk space.
+         * Otherwise, directly convert the size to bytes.
+         */
+        if (PartSize == MaxSize)
+            PartSize = MaxPartSize;
+        else // if (PartSize < MaxSize)
+            PartSize *= MB;
+        DPRINT("Partition size: %I64u bytes\n", PartSize);
 
-            if (PartCreateType == PartTypeData)
-            {
-                CreatePartition(PartitionList,
-                                CurrentPartition,
-                                SectorCount,
-                                FALSE);
-            }
-            else // if (PartCreateType == PartTypeExtended)
-            {
-                CreateExtendedPartition(PartitionList,
-                                        CurrentPartition,
-                                        SectorCount);
-            }
+        ASSERT(PartSize <= MaxPartSize);
 
-            return SELECT_PARTITION_PAGE;
+        if (PartCreateType == PartTypeData)
+        {
+            CreatePartition(PartitionList,
+                            CurrentPartition,
+                            PartSize);
         }
+        else // if (PartCreateType == PartTypeExtended)
+        {
+            CreateExtendedPartition(PartitionList,
+                                    CurrentPartition,
+                                    PartSize);
+        }
+
+        return SELECT_PARTITION_PAGE;
     }
 
     return CREATE_PARTITION_PAGE;
@@ -2392,10 +2390,14 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
          */
         if (!SystemPartition->IsPartitioned)
         {
+            /* Automatically create the partition; it will be
+             * formatted later with default parameters */
+            // FIXME: Don't use the whole empty space, but a minimal size
+            // specified from the TXTSETUP.SIF or unattended setup.
             CreatePartition(PartitionList,
                             SystemPartition,
-                            0LL, // SystemPartition->SectorCount.QuadPart,
-                            TRUE);
+                            0ULL);
+            SystemPartition->New |= PARTITION_NEW_AUTOCREATE;
             ASSERT(SystemPartition->IsPartitioned);
         }
 
@@ -2548,9 +2550,9 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
 
     MUIDisplayPage(SELECT_FILE_SYSTEM_PAGE);
 
-    if (PartEntry->AutoCreate)
+    if (PartEntry->New & PARTITION_NEW_AUTOCREATE)
     {
-        PartEntry->AutoCreate = FALSE;
+        PartEntry->New &= ~PARTITION_NEW_AUTOCREATE;
 
         CONSOLE_SetTextXY(6, 8, MUIGetString(STRING_NEWPARTITION));
     }