reactos/drivers/filesystems/fastfat/rw.c

   1 /*
   2  * COPYRIGHT:        See COPYING in the top level directory
   3  * PROJECT:          ReactOS kernel
   4  * FILE:             drivers/fs/vfat/rw.c
   5  * PURPOSE:          VFAT Filesystem
   6  * PROGRAMMER:       Jason Filby (jasonfilby@yahoo.com)
   7  *
   8  */
   9
  10 /* INCLUDES *****************************************************************/
  11
  12 #include "vfat.h"
  13
  14 #define NDEBUG
  15 #include <debug.h>
  16
  17 /*
  18  * Uncomment to enable strict verification of cluster/offset pair
  19  * caching. If this option is enabled you lose all the benefits of
  20  * the caching and the read/write operations will actually be
  21  * slower. It's meant only for debugging!!!
  22  * - Filip Navara, 26/07/2004
  23  */
  24 /* #define DEBUG_VERIFY_OFFSET_CACHING */
  25
  26 /* FUNCTIONS *****************************************************************/
  27
  28 /*
  29  * Return the next cluster in a FAT chain, possibly extending the chain if
  30  * necessary
  31  */
  32 NTSTATUS
  33 NextCluster(
  34     PDEVICE_EXTENSION DeviceExt,
  35     ULONG FirstCluster,
  36     PULONG CurrentCluster,
  37     BOOLEAN Extend)
  38 {
  39     if (FirstCluster == 1)
  40     {
  41         (*CurrentCluster) += DeviceExt->FatInfo.SectorsPerCluster;
  42         return STATUS_SUCCESS;
  43     }
  44     else
  45     {
  46         if (Extend)
  47             return GetNextClusterExtend(DeviceExt, (*CurrentCluster), CurrentCluster);
  48         else
  49             return GetNextCluster(DeviceExt, (*CurrentCluster), CurrentCluster);
  50     }
  51 }
  52
  53 NTSTATUS
  54 OffsetToCluster(
  55     PDEVICE_EXTENSION DeviceExt,
  56     ULONG FirstCluster,
  57     ULONG FileOffset,
  58     PULONG Cluster,
  59     BOOLEAN Extend)
  60 {
  61     ULONG CurrentCluster;
  62     ULONG i;
  63     NTSTATUS Status;
  64 /*
  65     DPRINT("OffsetToCluster(DeviceExt %x, Fcb %x, FirstCluster %x,"
  66            " FileOffset %x, Cluster %x, Extend %d)\n", DeviceExt,
  67            Fcb, FirstCluster, FileOffset, Cluster, Extend);
  68 */
  69     if (FirstCluster == 0)
  70     {
  71         DbgPrint("OffsetToCluster is called with FirstCluster = 0!\n");
  72         ASSERT(FALSE);
  73     }
  74
  75     if (FirstCluster == 1)
  76     {
  77         /* root of FAT16 or FAT12 */
  78         *Cluster = DeviceExt->FatInfo.rootStart + FileOffset
  79             / (DeviceExt->FatInfo.BytesPerCluster) * DeviceExt->FatInfo.SectorsPerCluster;
  80         return STATUS_SUCCESS;
  81     }
  82     else
  83     {
  84         CurrentCluster = FirstCluster;
  85         if (Extend)
  86         {
  87             for (i = 0; i < FileOffset / DeviceExt->FatInfo.BytesPerCluster; i++)
  88             {
  89                 Status = GetNextClusterExtend (DeviceExt, CurrentCluster, &CurrentCluster);
  90                 if (!NT_SUCCESS(Status))
  91                     return Status;
  92             }
  93             *Cluster = CurrentCluster;
  94         }
  95         else
  96         {
  97             for (i = 0; i < FileOffset / DeviceExt->FatInfo.BytesPerCluster; i++)
  98             {
  99                 Status = GetNextCluster (DeviceExt, CurrentCluster, &CurrentCluster);
 100                 if (!NT_SUCCESS(Status))
 101                     return Status;
 102             }
 103             *Cluster = CurrentCluster;
 104        }
 105        return STATUS_SUCCESS;
 106    }
 107 }
 108
 109 /*
 110  * FUNCTION: Reads data from a file
 111  */
 112 static
 113 NTSTATUS
 114 VfatReadFileData(
 115     PVFAT_IRP_CONTEXT IrpContext,
 116     ULONG Length,
 117     LARGE_INTEGER ReadOffset,
 118     PULONG LengthRead)
 119 {
 120     ULONG CurrentCluster;
 121     ULONG FirstCluster;
 122     ULONG StartCluster;
 123     ULONG ClusterCount;
 124     LARGE_INTEGER StartOffset;
 125     PDEVICE_EXTENSION DeviceExt;
 126     BOOLEAN First = TRUE;
 127     PVFATFCB Fcb;
 128     NTSTATUS Status;
 129     ULONG BytesDone;
 130     ULONG BytesPerSector;
 131     ULONG BytesPerCluster;
 132     ULONG LastCluster;
 133     ULONG LastOffset;
 134
 135     /* PRECONDITION */
 136     ASSERT(IrpContext);
 137     DeviceExt = IrpContext->DeviceExt;
 138     ASSERT(DeviceExt);
 139     ASSERT(DeviceExt->FatInfo.BytesPerCluster);
 140     ASSERT(IrpContext->FileObject);
 141     ASSERT(IrpContext->FileObject->FsContext2 != NULL);
 142
 143     DPRINT("VfatReadFileData(DeviceExt %p, FileObject %p, "
 144            "Length %u, ReadOffset 0x%I64x)\n", DeviceExt,
 145            IrpContext->FileObject, Length, ReadOffset.QuadPart);
 146
 147     *LengthRead = 0;
 148
 149     Fcb = IrpContext->FileObject->FsContext;
 150     BytesPerSector = DeviceExt->FatInfo.BytesPerSector;
 151     BytesPerCluster = DeviceExt->FatInfo.BytesPerCluster;
 152
 153     ASSERT(ReadOffset.QuadPart + Length <= ROUND_UP_64(Fcb->RFCB.FileSize.QuadPart, BytesPerSector));
 154     ASSERT(ReadOffset.u.LowPart % BytesPerSector == 0);
 155     ASSERT(Length % BytesPerSector == 0);
 156
 157     /* Is this a read of the FAT? */
 158     if (Fcb->Flags & FCB_IS_FAT)
 159     {
 160         ReadOffset.QuadPart += DeviceExt->FatInfo.FATStart * BytesPerSector;
 161         Status = VfatReadDiskPartial(IrpContext, &ReadOffset, Length, 0, TRUE);
 162
 163         if (NT_SUCCESS(Status))
 164         {
 165             *LengthRead = Length;
 166         }
 167         else
 168         {
 169             DPRINT1("FAT reading failed, Status %x\n", Status);
 170         }
 171         return Status;
 172     }
 173
 174     /* Is this a read of the Volume ? */
 175     if (Fcb->Flags & FCB_IS_VOLUME)
 176     {
 177         Status = VfatReadDiskPartial(IrpContext, &ReadOffset, Length, 0, TRUE);
 178         if (NT_SUCCESS(Status))
 179         {
 180             *LengthRead = Length;
 181         }
 182         else
 183         {
 184             DPRINT1("Volume reading failed, Status %x\n", Status);
 185         }
 186         return Status;
 187     }
 188
 189     /* Find the first cluster */
 190     FirstCluster =
 191     CurrentCluster = vfatDirEntryGetFirstCluster (DeviceExt, &Fcb->entry);
 192
 193     if (FirstCluster == 1)
 194     {
 195         /* Directory of FAT12/16 needs a special handling */
 196         if (ReadOffset.u.LowPart + Length > DeviceExt->FatInfo.rootDirectorySectors * BytesPerSector)
 197         {
 198             Length = DeviceExt->FatInfo.rootDirectorySectors * BytesPerSector - ReadOffset.u.LowPart;
 199         }
 200         ReadOffset.u.LowPart += DeviceExt->FatInfo.rootStart * BytesPerSector;
 201
 202         /* Fire up the read command */
 203         Status = VfatReadDiskPartial (IrpContext, &ReadOffset, Length, 0, TRUE);
 204         if (NT_SUCCESS(Status))
 205         {
 206             *LengthRead = Length;
 207         }
 208         return Status;
 209     }
 210
 211     ExAcquireFastMutex(&Fcb->LastMutex);
 212     LastCluster = Fcb->LastCluster;
 213     LastOffset = Fcb->LastOffset;
 214     ExReleaseFastMutex(&Fcb->LastMutex);
 215
 216     /* Find the cluster to start the read from */
 217     if (LastCluster > 0 && ReadOffset.u.LowPart >= LastOffset)
 218     {
 219         Status = OffsetToCluster(DeviceExt, LastCluster,
 220                                  ROUND_DOWN(ReadOffset.u.LowPart, BytesPerCluster) -
 221                                  LastOffset,
 222                                  &CurrentCluster, FALSE);
 223 #ifdef DEBUG_VERIFY_OFFSET_CACHING
 224         /* DEBUG VERIFICATION */
 225         {
 226             ULONG CorrectCluster;
 227             OffsetToCluster(DeviceExt, FirstCluster,
 228                             ROUND_DOWN(ReadOffset.u.LowPart, BytesPerCluster),
 229                             &CorrectCluster, FALSE);
 230             if (CorrectCluster != CurrentCluster)
 231                 KeBugCheck(FAT_FILE_SYSTEM);
 232         }
 233 #endif
 234     }
 235     else
 236     {
 237         Status = OffsetToCluster(DeviceExt, FirstCluster,
 238                                  ROUND_DOWN(ReadOffset.u.LowPart, BytesPerCluster),
 239                                  &CurrentCluster, FALSE);
 240     }
 241
 242     if (!NT_SUCCESS(Status))
 243     {
 244         return Status;
 245     }
 246
 247     ExAcquireFastMutex(&Fcb->LastMutex);
 248     Fcb->LastCluster = CurrentCluster;
 249     Fcb->LastOffset = ROUND_DOWN (ReadOffset.u.LowPart, BytesPerCluster);
 250     ExReleaseFastMutex(&Fcb->LastMutex);
 251
 252     KeInitializeEvent(&IrpContext->Event, NotificationEvent, FALSE);
 253     IrpContext->RefCount = 1;
 254
 255     while (Length > 0 && CurrentCluster != 0xffffffff)
 256     {
 257         StartCluster = CurrentCluster;
 258         StartOffset.QuadPart = ClusterToSector(DeviceExt, StartCluster) * BytesPerSector;
 259         BytesDone = 0;
 260         ClusterCount = 0;
 261
 262         do
 263         {
 264             ClusterCount++;
 265             if (First)
 266             {
 267                 BytesDone =  min (Length, BytesPerCluster - (ReadOffset.u.LowPart % BytesPerCluster));
 268                 StartOffset.QuadPart += ReadOffset.u.LowPart % BytesPerCluster;
 269                 First = FALSE;
 270             }
 271             else
 272             {
 273                 if (Length - BytesDone > BytesPerCluster)
 274                 {
 275                     BytesDone += BytesPerCluster;
 276                 }
 277                 else
 278                 {
 279                     BytesDone = Length;
 280                 }
 281             }
 282             Status = NextCluster(DeviceExt, FirstCluster, &CurrentCluster, FALSE);
 283         }
 284         while (StartCluster + ClusterCount == CurrentCluster && NT_SUCCESS(Status) && Length > BytesDone);
 285         DPRINT("start %08x, next %08x, count %u\n",
 286                StartCluster, CurrentCluster, ClusterCount);
 287
 288         ExAcquireFastMutex(&Fcb->LastMutex);
 289         Fcb->LastCluster = StartCluster + (ClusterCount - 1);
 290         Fcb->LastOffset = ROUND_DOWN(ReadOffset.u.LowPart, BytesPerCluster) + (ClusterCount - 1) * BytesPerCluster;
 291         ExReleaseFastMutex(&Fcb->LastMutex);
 292
 293         /* Fire up the read command */
 294         Status = VfatReadDiskPartial (IrpContext, &StartOffset, BytesDone, *LengthRead, FALSE);
 295         if (!NT_SUCCESS(Status) && Status != STATUS_PENDING)
 296         {
 297             break;
 298         }
 299         *LengthRead += BytesDone;
 300         Length -= BytesDone;
 301         ReadOffset.u.LowPart += BytesDone;
 302     }
 303
 304     if (InterlockedDecrement((PLONG)&IrpContext->RefCount) != 0)
 305     {
 306         KeWaitForSingleObject(&IrpContext->Event, Executive, KernelMode, FALSE, NULL);
 307     }
 308
 309     if (NT_SUCCESS(Status) || Status == STATUS_PENDING)
 310     {
 311         if (Length > 0)
 312         {
 313             Status = STATUS_UNSUCCESSFUL;
 314         }
 315         else
 316         {
 317             Status = IrpContext->Irp->IoStatus.Status;
 318         }
 319     }
 320
 321     return Status;
 322 }
 323
 324 static
 325 NTSTATUS
 326 VfatWriteFileData(
 327     PVFAT_IRP_CONTEXT IrpContext,
 328     ULONG Length,
 329     LARGE_INTEGER WriteOffset)
 330 {
 331     PDEVICE_EXTENSION DeviceExt;
 332     PVFATFCB Fcb;
 333     ULONG Count;
 334     ULONG FirstCluster;
 335     ULONG CurrentCluster;
 336     ULONG BytesDone;
 337     ULONG StartCluster;
 338     ULONG ClusterCount;
 339     NTSTATUS Status = STATUS_SUCCESS;
 340     BOOLEAN First = TRUE;
 341     ULONG BytesPerSector;
 342     ULONG BytesPerCluster;
 343     LARGE_INTEGER StartOffset;
 344     ULONG BufferOffset;
 345     ULONG LastCluster;
 346     ULONG LastOffset;
 347
 348     /* PRECONDITION */
 349     ASSERT(IrpContext);
 350     DeviceExt = IrpContext->DeviceExt;
 351     ASSERT(DeviceExt);
 352     ASSERT(DeviceExt->FatInfo.BytesPerCluster);
 353     ASSERT(IrpContext->FileObject);
 354     ASSERT(IrpContext->FileObject->FsContext2 != NULL);
 355
 356     Fcb = IrpContext->FileObject->FsContext;
 357     BytesPerCluster = DeviceExt->FatInfo.BytesPerCluster;
 358     BytesPerSector = DeviceExt->FatInfo.BytesPerSector;
 359
 360     DPRINT("VfatWriteFileData(DeviceExt %p, FileObject %p, "
 361            "Length %u, WriteOffset 0x%I64x), '%wZ'\n", DeviceExt,
 362            IrpContext->FileObject, Length, WriteOffset.QuadPart,
 363            &Fcb->PathNameU);
 364
 365     ASSERT(WriteOffset.QuadPart + Length <= Fcb->RFCB.AllocationSize.QuadPart);
 366     ASSERT(WriteOffset.u.LowPart % BytesPerSector == 0);
 367     ASSERT(Length % BytesPerSector == 0);
 368
 369     /* Is this a write of the volume? */
 370     if (Fcb->Flags & FCB_IS_VOLUME)
 371     {
 372         Status = VfatWriteDiskPartial(IrpContext, &WriteOffset, Length, 0, TRUE);
 373         if (!NT_SUCCESS(Status))
 374         {
 375             DPRINT1("Volume writing failed, Status %x\n", Status);
 376         }
 377         return Status;
 378     }
 379
 380     /* Is this a write to the FAT? */
 381     if (Fcb->Flags & FCB_IS_FAT)
 382     {
 383         WriteOffset.u.LowPart += DeviceExt->FatInfo.FATStart * BytesPerSector;
 384         IrpContext->RefCount = 1;
 385         for (Count = 0; Count < DeviceExt->FatInfo.FATCount; Count++)
 386         {
 387             Status = VfatWriteDiskPartial(IrpContext, &WriteOffset, Length, 0, FALSE);
 388             if (!NT_SUCCESS(Status) && Status != STATUS_PENDING)
 389             {
 390                 DPRINT1("FAT writing failed, Status %x\n", Status);
 391                 break;
 392             }
 393             WriteOffset.u.LowPart += Fcb->RFCB.FileSize.u.LowPart;
 394         }
 395
 396         if (InterlockedDecrement((PLONG)&IrpContext->RefCount) != 0)
 397         {
 398             KeWaitForSingleObject(&IrpContext->Event, Executive, KernelMode, FALSE, NULL);
 399         }
 400
 401         if (NT_SUCCESS(Status) || Status == STATUS_PENDING)
 402         {
 403             Status = IrpContext->Irp->IoStatus.Status;
 404         }
 405         return Status;
 406     }
 407
 408     /*
 409      * Find the first cluster
 410      */
 411     FirstCluster =
 412     CurrentCluster = vfatDirEntryGetFirstCluster (DeviceExt, &Fcb->entry);
 413
 414     if (FirstCluster == 1)
 415     {
 416         ASSERT(WriteOffset.u.LowPart + Length <= DeviceExt->FatInfo.rootDirectorySectors * BytesPerSector);
 417         // Directory of FAT12/16 needs a special handling
 418         WriteOffset.u.LowPart += DeviceExt->FatInfo.rootStart * BytesPerSector;
 419         // Fire up the write command
 420         Status = VfatWriteDiskPartial (IrpContext, &WriteOffset, Length, 0, TRUE);
 421         return Status;
 422     }
 423
 424     ExAcquireFastMutex(&Fcb->LastMutex);
 425     LastCluster = Fcb->LastCluster;
 426     LastOffset = Fcb->LastOffset;
 427     ExReleaseFastMutex(&Fcb->LastMutex);
 428
 429     /*
 430      * Find the cluster to start the write from
 431      */
 432     if (LastCluster > 0 && WriteOffset.u.LowPart >= LastOffset)
 433     {
 434         Status = OffsetToCluster(DeviceExt, LastCluster,
 435                                  ROUND_DOWN(WriteOffset.u.LowPart, BytesPerCluster) -
 436                                  LastOffset,
 437                                  &CurrentCluster, FALSE);
 438 #ifdef DEBUG_VERIFY_OFFSET_CACHING
 439         /* DEBUG VERIFICATION */
 440         {
 441             ULONG CorrectCluster;
 442             OffsetToCluster(DeviceExt, FirstCluster,
 443                             ROUND_DOWN(WriteOffset.u.LowPart, BytesPerCluster),
 444                             &CorrectCluster, FALSE);
 445             if (CorrectCluster != CurrentCluster)
 446                 KeBugCheck(FAT_FILE_SYSTEM);
 447         }
 448 #endif
 449     }
 450     else
 451     {
 452         Status = OffsetToCluster(DeviceExt, FirstCluster,
 453                                  ROUND_DOWN(WriteOffset.u.LowPart, BytesPerCluster),
 454                                  &CurrentCluster, FALSE);
 455     }
 456
 457     if (!NT_SUCCESS(Status))
 458     {
 459         return Status;
 460     }
 461
 462     ExAcquireFastMutex(&Fcb->LastMutex);
 463     Fcb->LastCluster = CurrentCluster;
 464     Fcb->LastOffset = ROUND_DOWN (WriteOffset.u.LowPart, BytesPerCluster);
 465     ExReleaseFastMutex(&Fcb->LastMutex);
 466
 467     IrpContext->RefCount = 1;
 468     BufferOffset = 0;
 469
 470     while (Length > 0 && CurrentCluster != 0xffffffff)
 471     {
 472         StartCluster = CurrentCluster;
 473         StartOffset.QuadPart = ClusterToSector(DeviceExt, StartCluster) * BytesPerSector;
 474         BytesDone = 0;
 475         ClusterCount = 0;
 476
 477         do
 478         {
 479             ClusterCount++;
 480             if (First)
 481             {
 482                 BytesDone =  min (Length, BytesPerCluster - (WriteOffset.u.LowPart % BytesPerCluster));
 483                 StartOffset.QuadPart += WriteOffset.u.LowPart % BytesPerCluster;
 484                 First = FALSE;
 485             }
 486             else
 487             {
 488                 if (Length - BytesDone > BytesPerCluster)
 489                 {
 490                     BytesDone += BytesPerCluster;
 491                 }
 492                 else
 493                 {
 494                     BytesDone = Length;
 495                 }
 496             }
 497             Status = NextCluster(DeviceExt, FirstCluster, &CurrentCluster, FALSE);
 498         }
 499         while (StartCluster + ClusterCount == CurrentCluster && NT_SUCCESS(Status) && Length > BytesDone);
 500         DPRINT("start %08x, next %08x, count %u\n",
 501                StartCluster, CurrentCluster, ClusterCount);
 502
 503         ExAcquireFastMutex(&Fcb->LastMutex);
 504         Fcb->LastCluster = StartCluster + (ClusterCount - 1);
 505         Fcb->LastOffset = ROUND_DOWN(WriteOffset.u.LowPart, BytesPerCluster) + (ClusterCount - 1) * BytesPerCluster;
 506         ExReleaseFastMutex(&Fcb->LastMutex);
 507
 508         // Fire up the write command
 509         Status = VfatWriteDiskPartial (IrpContext, &StartOffset, BytesDone, BufferOffset, FALSE);
 510         if (!NT_SUCCESS(Status) && Status != STATUS_PENDING)
 511         {
 512             break;
 513         }
 514         BufferOffset += BytesDone;
 515         Length -= BytesDone;
 516         WriteOffset.u.LowPart += BytesDone;
 517     }
 518
 519     if (InterlockedDecrement((PLONG)&IrpContext->RefCount) != 0)
 520     {
 521         KeWaitForSingleObject(&IrpContext->Event, Executive, KernelMode, FALSE, NULL);
 522     }
 523
 524     if (NT_SUCCESS(Status) || Status == STATUS_PENDING)
 525     {
 526         if (Length > 0)
 527         {
 528             Status = STATUS_UNSUCCESSFUL;
 529         }
 530         else
 531         {
 532             Status = IrpContext->Irp->IoStatus.Status;
 533         }
 534     }
 535     return Status;
 536 }
 537
 538 NTSTATUS
 539 VfatRead(
 540     PVFAT_IRP_CONTEXT IrpContext)
 541 {
 542     NTSTATUS Status;
 543     PVFATFCB Fcb;
 544     ULONG Length = 0;
 545     ULONG ReturnedLength = 0;
 546     PERESOURCE Resource = NULL;
 547     LARGE_INTEGER ByteOffset;
 548     PVOID Buffer;
 549     ULONG BytesPerSector;
 550
 551     ASSERT(IrpContext);
 552
 553     DPRINT("VfatRead(IrpContext %p)\n", IrpContext);
 554
 555     ASSERT(IrpContext->DeviceObject);
 556
 557     // This request is not allowed on the main device object
 558     if (IrpContext->DeviceObject == VfatGlobalData->DeviceObject)
 559     {
 560         DPRINT("VfatRead is called with the main device object.\n");
 561         Status = STATUS_INVALID_DEVICE_REQUEST;
 562         goto ByeBye;
 563     }
 564
 565     ASSERT(IrpContext->DeviceExt);
 566     ASSERT(IrpContext->FileObject);
 567     Fcb = IrpContext->FileObject->FsContext;
 568     ASSERT(Fcb);
 569
 570     if (Fcb->Flags & FCB_IS_PAGE_FILE)
 571     {
 572         PFATINFO FatInfo = &IrpContext->DeviceExt->FatInfo;
 573         IrpContext->Stack->Parameters.Read.ByteOffset.QuadPart += FatInfo->dataStart * FatInfo->BytesPerSector;
 574         IoSkipCurrentIrpStackLocation(IrpContext->Irp);
 575         IrpContext->Flags &= ~IRPCONTEXT_COMPLETE;
 576         DPRINT("Read from page file, disk offset %I64x\n", IrpContext->Stack->Parameters.Read.ByteOffset.QuadPart);
 577         Status = IoCallDriver(IrpContext->DeviceExt->StorageDevice, IrpContext->Irp);
 578         return Status;
 579     }
 580
 581     DPRINT("<%wZ>\n", &Fcb->PathNameU);
 582
 583     ByteOffset = IrpContext->Stack->Parameters.Read.ByteOffset;
 584     Length = IrpContext->Stack->Parameters.Read.Length;
 585     BytesPerSector = IrpContext->DeviceExt->FatInfo.BytesPerSector;
 586
 587     /* fail if file is a directory and no paged read */
 588     if (*Fcb->Attributes & FILE_ATTRIBUTE_DIRECTORY && !(IrpContext->Irp->Flags & IRP_PAGING_IO))
 589     {
 590         Status = STATUS_INVALID_PARAMETER;
 591         goto ByeBye;
 592     }
 593
 594     DPRINT("'%wZ', Offset: %u, Length %u\n", &Fcb->PathNameU, ByteOffset.u.LowPart, Length);
 595
 596     if (ByteOffset.u.HighPart && !(Fcb->Flags & FCB_IS_VOLUME))
 597     {
 598        Status = STATUS_INVALID_PARAMETER;
 599        goto ByeBye;
 600     }
 601
 602     if (Length == 0)
 603     {
 604         IrpContext->Irp->IoStatus.Information = 0;
 605         Status = STATUS_SUCCESS;
 606         goto ByeBye;
 607     }
 608
 609     if (ByteOffset.QuadPart >= Fcb->RFCB.FileSize.QuadPart)
 610     {
 611        IrpContext->Irp->IoStatus.Information = 0;
 612        Status = STATUS_END_OF_FILE;
 613        goto ByeBye;
 614     }
 615
 616     if (IrpContext->Irp->Flags & (IRP_PAGING_IO | IRP_NOCACHE) || (Fcb->Flags & FCB_IS_VOLUME))
 617     {
 618         if (ByteOffset.u.LowPart % BytesPerSector != 0 || Length % BytesPerSector != 0)
 619         {
 620             DPRINT("%u %u\n", ByteOffset.u.LowPart, Length);
 621             // non cached read must be sector aligned
 622             Status = STATUS_INVALID_PARAMETER;
 623             goto ByeBye;
 624         }
 625     }
 626
 627     if (Fcb->Flags & FCB_IS_VOLUME)
 628     {
 629         Resource = &IrpContext->DeviceExt->DirResource;
 630     }
 631     else if (IrpContext->Irp->Flags & IRP_PAGING_IO)
 632     {
 633         Resource = &Fcb->PagingIoResource;
 634     }
 635     else
 636     {
 637         Resource = &Fcb->MainResource;
 638     }
 639
 640     if (!ExAcquireResourceSharedLite(Resource,
 641                                      IrpContext->Flags & IRPCONTEXT_CANWAIT ? TRUE : FALSE))
 642     {
 643         Resource = NULL;
 644         Status = STATUS_PENDING;
 645         goto ByeBye;
 646     }
 647
 648     if (!(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
 649         FsRtlAreThereCurrentFileLocks(&Fcb->FileLock))
 650     {
 651         if (!FsRtlCheckLockForReadAccess(&Fcb->FileLock, IrpContext->Irp))
 652         {
 653             Status = STATUS_FILE_LOCK_CONFLICT;
 654             goto ByeBye;
 655         }
 656     }
 657
 658     Buffer = VfatGetUserBuffer(IrpContext->Irp, BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
 659     Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoWriteAccess);
 660     if (!NT_SUCCESS(Status))
 661     {
 662         goto ByeBye;
 663     }
 664
 665     if (!(IrpContext->Irp->Flags & (IRP_NOCACHE|IRP_PAGING_IO)) &&
 666         !(Fcb->Flags & (FCB_IS_PAGE_FILE|FCB_IS_VOLUME)))
 667     {
 668         // cached read
 669         Status = STATUS_SUCCESS;
 670         if (ByteOffset.u.LowPart + Length > Fcb->RFCB.FileSize.u.LowPart)
 671         {
 672             Length = Fcb->RFCB.FileSize.u.LowPart - ByteOffset.u.LowPart;
 673             Status = /*STATUS_END_OF_FILE*/STATUS_SUCCESS;
 674         }
 675
 676         _SEH2_TRY
 677         {
 678             if (IrpContext->FileObject->PrivateCacheMap == NULL)
 679             {
 680                 CcInitializeCacheMap(IrpContext->FileObject,
 681                                      (PCC_FILE_SIZES)(&Fcb->RFCB.AllocationSize),
 682                                      FALSE,
 683                                      &(VfatGlobalData->CacheMgrCallbacks),
 684                                      Fcb);
 685             }
 686
 687             if (!CcCopyRead(IrpContext->FileObject,
 688                             &ByteOffset,
 689                             Length,
 690                             (IrpContext->Flags & IRPCONTEXT_CANWAIT) != 0,
 691                             Buffer,
 692                             &IrpContext->Irp->IoStatus))
 693             {
 694                 ASSERT((IrpContext->Flags & IRPCONTEXT_CANWAIT) == 0);
 695                 Status = STATUS_PENDING;
 696                 goto ByeBye;
 697             }
 698         }
 699         _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
 700         {
 701             Status = _SEH2_GetExceptionCode();
 702             goto ByeBye;
 703         }
 704         _SEH2_END;
 705
 706         if (!NT_SUCCESS(IrpContext->Irp->IoStatus.Status))
 707         {
 708             Status = IrpContext->Irp->IoStatus.Status;
 709         }
 710     }
 711     else
 712     {
 713         // non cached read
 714         if (ByteOffset.QuadPart + Length > ROUND_UP_64(Fcb->RFCB.FileSize.QuadPart, BytesPerSector))
 715         {
 716             Length = (ULONG)(ROUND_UP_64(Fcb->RFCB.FileSize.QuadPart, BytesPerSector) - ByteOffset.QuadPart);
 717         }
 718
 719         Status = VfatReadFileData(IrpContext, Length, ByteOffset, &ReturnedLength);
 720         if (NT_SUCCESS(Status))
 721         {
 722             IrpContext->Irp->IoStatus.Information = ReturnedLength;
 723         }
 724     }
 725
 726 ByeBye:
 727     if (Resource)
 728     {
 729         ExReleaseResourceLite(Resource);
 730     }
 731
 732     if (Status == STATUS_PENDING)
 733     {
 734         Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoWriteAccess);
 735         if (NT_SUCCESS(Status))
 736         {
 737             Status = VfatMarkIrpContextForQueue(IrpContext);
 738         }
 739     }
 740     else
 741     {
 742         IrpContext->Irp->IoStatus.Status = Status;
 743         if (IrpContext->FileObject->Flags & FO_SYNCHRONOUS_IO &&
 744             !(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
 745             (NT_SUCCESS(Status) || Status == STATUS_END_OF_FILE))
 746         {
 747             IrpContext->FileObject->CurrentByteOffset.QuadPart =
 748                 ByteOffset.QuadPart + IrpContext->Irp->IoStatus.Information;
 749         }
 750
 751         if (NT_SUCCESS(Status))
 752             IrpContext->PriorityBoost = IO_DISK_INCREMENT;
 753     }
 754     DPRINT("%x\n", Status);
 755     return Status;
 756 }
 757
 758 NTSTATUS
 759 VfatWrite(
 760     PVFAT_IRP_CONTEXT IrpContext)
 761 {
 762     PVFATFCB Fcb;
 763     PERESOURCE Resource = NULL;
 764     LARGE_INTEGER ByteOffset;
 765     LARGE_INTEGER OldFileSize;
 766     NTSTATUS Status = STATUS_SUCCESS;
 767     ULONG Length = 0;
 768     PVOID Buffer;
 769     ULONG BytesPerSector;
 770
 771     ASSERT(IrpContext);
 772
 773     DPRINT("VfatWrite(IrpContext %p)\n", IrpContext);
 774
 775     ASSERT(IrpContext->DeviceObject);
 776
 777     // This request is not allowed on the main device object
 778     if (IrpContext->DeviceObject == VfatGlobalData->DeviceObject)
 779     {
 780         DPRINT("VfatWrite is called with the main device object.\n");
 781         Status = STATUS_INVALID_DEVICE_REQUEST;
 782         goto ByeBye;
 783     }
 784
 785     ASSERT(IrpContext->DeviceExt);
 786     ASSERT(IrpContext->FileObject);
 787     Fcb = IrpContext->FileObject->FsContext;
 788     ASSERT(Fcb);
 789
 790     if (Fcb->Flags & FCB_IS_PAGE_FILE)
 791     {
 792         PFATINFO FatInfo = &IrpContext->DeviceExt->FatInfo;
 793         IrpContext->Stack->Parameters.Write.ByteOffset.QuadPart += FatInfo->dataStart * FatInfo->BytesPerSector;
 794         IoSkipCurrentIrpStackLocation(IrpContext->Irp);
 795         IrpContext->Flags &= ~IRPCONTEXT_COMPLETE;
 796         DPRINT("Write to page file, disk offset %I64x\n", IrpContext->Stack->Parameters.Write.ByteOffset.QuadPart);
 797         Status = IoCallDriver(IrpContext->DeviceExt->StorageDevice, IrpContext->Irp);
 798         return Status;
 799     }
 800
 801     DPRINT("<%wZ>\n", &Fcb->PathNameU);
 802
 803     /* fail if file is a directory and no paged read */
 804     if (*Fcb->Attributes & FILE_ATTRIBUTE_DIRECTORY && !(IrpContext->Irp->Flags & IRP_PAGING_IO))
 805     {
 806         Status = STATUS_INVALID_PARAMETER;
 807         goto ByeBye;
 808     }
 809
 810     ByteOffset = IrpContext->Stack->Parameters.Write.ByteOffset;
 811     if (ByteOffset.u.LowPart == FILE_WRITE_TO_END_OF_FILE &&
 812         ByteOffset.u.HighPart == -1)
 813     {
 814         ByteOffset.QuadPart = Fcb->RFCB.FileSize.QuadPart;
 815     }
 816     Length = IrpContext->Stack->Parameters.Write.Length;
 817     BytesPerSector = IrpContext->DeviceExt->FatInfo.BytesPerSector;
 818
 819     if (ByteOffset.u.HighPart && !(Fcb->Flags & FCB_IS_VOLUME))
 820     {
 821         Status = STATUS_INVALID_PARAMETER;
 822         goto ByeBye;
 823     }
 824
 825     if (Fcb->Flags & (FCB_IS_FAT | FCB_IS_VOLUME) ||
 826         vfatDirEntryGetFirstCluster(IrpContext->DeviceExt, &Fcb->entry) == 1)
 827     {
 828         if (ByteOffset.QuadPart + Length > Fcb->RFCB.FileSize.QuadPart)
 829         {
 830             // we can't extend the FAT, the volume or the root on FAT12/FAT16
 831             Status = STATUS_END_OF_FILE;
 832             goto ByeBye;
 833         }
 834     }
 835
 836     if (IrpContext->Irp->Flags & (IRP_PAGING_IO|IRP_NOCACHE) || (Fcb->Flags & FCB_IS_VOLUME))
 837     {
 838         if (ByteOffset.u.LowPart % BytesPerSector != 0 || Length % BytesPerSector != 0)
 839         {
 840             // non cached write must be sector aligned
 841             Status = STATUS_INVALID_PARAMETER;
 842             goto ByeBye;
 843         }
 844     }
 845
 846     OldFileSize = Fcb->RFCB.FileSize;
 847
 848     if (Length == 0)
 849     {
 850         /* Update last write time */
 851         IrpContext->Irp->IoStatus.Information = 0;
 852         Status = STATUS_SUCCESS;
 853         goto Metadata;
 854     }
 855
 856     if (IrpContext->Irp->Flags & IRP_PAGING_IO)
 857     {
 858         if (ByteOffset.u.LowPart + Length > Fcb->RFCB.AllocationSize.u.LowPart)
 859         {
 860             Status = STATUS_INVALID_PARAMETER;
 861             goto ByeBye;
 862         }
 863
 864         if (ByteOffset.u.LowPart + Length > ROUND_UP(Fcb->RFCB.AllocationSize.u.LowPart, BytesPerSector))
 865         {
 866             Length =  ROUND_UP(Fcb->RFCB.FileSize.u.LowPart, BytesPerSector) - ByteOffset.u.LowPart;
 867         }
 868     }
 869
 870     if (Fcb->Flags & FCB_IS_VOLUME)
 871     {
 872         Resource = &IrpContext->DeviceExt->DirResource;
 873     }
 874     else if (IrpContext->Irp->Flags & IRP_PAGING_IO)
 875     {
 876         Resource = &Fcb->PagingIoResource;
 877     }
 878     else
 879     {
 880         Resource = &Fcb->MainResource;
 881     }
 882
 883     if ((Fcb->Flags & FCB_IS_PAGE_FILE) || (IrpContext->Irp->Flags & IRP_PAGING_IO))
 884     {
 885         if (!ExAcquireResourceSharedLite(Resource,
 886                                          BooleanFlagOn(IrpContext->Flags, IRPCONTEXT_CANWAIT)))
 887         {
 888             Resource = NULL;
 889             Status = STATUS_PENDING;
 890             goto ByeBye;
 891         }
 892     }
 893     else
 894     {
 895         if (!ExAcquireResourceExclusiveLite(Resource,
 896                                             BooleanFlagOn(IrpContext->Flags, IRPCONTEXT_CANWAIT)))
 897         {
 898             Resource = NULL;
 899             Status = STATUS_PENDING;
 900             goto ByeBye;
 901         }
 902     }
 903
 904     if (!(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
 905         FsRtlAreThereCurrentFileLocks(&Fcb->FileLock))
 906     {
 907         if (!FsRtlCheckLockForWriteAccess(&Fcb->FileLock, IrpContext->Irp))
 908         {
 909             Status = STATUS_FILE_LOCK_CONFLICT;
 910             goto ByeBye;
 911         }
 912     }
 913
 914     if (!(IrpContext->Flags & IRPCONTEXT_CANWAIT) && !(Fcb->Flags & FCB_IS_VOLUME))
 915     {
 916         if (ByteOffset.u.LowPart + Length > Fcb->RFCB.AllocationSize.u.LowPart)
 917         {
 918             Status = STATUS_PENDING;
 919             goto ByeBye;
 920         }
 921     }
 922
 923     Buffer = VfatGetUserBuffer(IrpContext->Irp, BooleanFlagOn(IrpContext->Irp->Flags, IRP_PAGING_IO));
 924     Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
 925     if (!NT_SUCCESS(Status))
 926     {
 927         Status = STATUS_INVALID_USER_BUFFER;
 928         goto ByeBye;
 929     }
 930
 931     if (!(Fcb->Flags & (FCB_IS_FAT|FCB_IS_VOLUME)) &&
 932         !(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
 933         ByteOffset.u.LowPart + Length > Fcb->RFCB.FileSize.u.LowPart)
 934     {
 935         LARGE_INTEGER AllocationSize;
 936         AllocationSize.QuadPart = ByteOffset.u.LowPart + Length;
 937         Status = VfatSetAllocationSizeInformation(IrpContext->FileObject, Fcb,
 938                                                   IrpContext->DeviceExt, &AllocationSize);
 939         if (!NT_SUCCESS (Status))
 940         {
 941             goto ByeBye;
 942         }
 943     }
 944
 945     if (!(IrpContext->Irp->Flags & (IRP_NOCACHE|IRP_PAGING_IO)) &&
 946         !(Fcb->Flags & (FCB_IS_PAGE_FILE|FCB_IS_VOLUME)))
 947     {
 948         // cached write
 949
 950         _SEH2_TRY
 951         {
 952             if (IrpContext->FileObject->PrivateCacheMap == NULL)
 953             {
 954                 CcInitializeCacheMap(IrpContext->FileObject,
 955                                      (PCC_FILE_SIZES)(&Fcb->RFCB.AllocationSize),
 956                                      FALSE,
 957                                      &VfatGlobalData->CacheMgrCallbacks,
 958                                      Fcb);
 959             }
 960
 961             if (ByteOffset.QuadPart > OldFileSize.QuadPart)
 962             {
 963                 CcZeroData(IrpContext->FileObject, &OldFileSize, &ByteOffset, TRUE);
 964             }
 965
 966             if (CcCopyWrite(IrpContext->FileObject,
 967                             &ByteOffset,
 968                             Length,
 969                             TRUE /*(IrpContext->Flags & IRPCONTEXT_CANWAIT) != 0*/,
 970                             Buffer))
 971             {
 972                 IrpContext->Irp->IoStatus.Information = Length;
 973                 Status = STATUS_SUCCESS;
 974             }
 975             else
 976             {
 977                 ASSERT(FALSE /*(IrpContext->Flags & IRPCONTEXT_CANWAIT) == 0*/);
 978                 Status = STATUS_UNSUCCESSFUL;
 979             }
 980         }
 981         _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER)
 982         {
 983             Status = _SEH2_GetExceptionCode();
 984         }
 985         _SEH2_END;
 986     }
 987     else
 988     {
 989         // non cached write
 990
 991         if (ByteOffset.QuadPart > OldFileSize.QuadPart)
 992         {
 993             CcZeroData(IrpContext->FileObject, &OldFileSize, &ByteOffset, TRUE);
 994         }
 995
 996         Status = VfatWriteFileData(IrpContext, Length, ByteOffset);
 997         if (NT_SUCCESS(Status))
 998         {
 999             IrpContext->Irp->IoStatus.Information = Length;
1000         }
1001     }
1002
1003 Metadata:
1004     if (!(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
1005         !(Fcb->Flags & (FCB_IS_FAT|FCB_IS_VOLUME)))
1006     {
1007         if(!(*Fcb->Attributes & FILE_ATTRIBUTE_DIRECTORY))
1008         {
1009             LARGE_INTEGER SystemTime;
1010             ULONG Filter;
1011
1012             // set dates and times
1013             KeQuerySystemTime (&SystemTime);
1014             if (Fcb->Flags & FCB_IS_FATX_ENTRY)
1015             {
1016                 FsdSystemTimeToDosDateTime(IrpContext->DeviceExt,
1017                                            &SystemTime, &Fcb->entry.FatX.UpdateDate,
1018                                            &Fcb->entry.FatX.UpdateTime);
1019                 Fcb->entry.FatX.AccessDate = Fcb->entry.FatX.UpdateDate;
1020                 Fcb->entry.FatX.AccessTime = Fcb->entry.FatX.UpdateTime;
1021             }
1022             else
1023             {
1024                 FsdSystemTimeToDosDateTime(IrpContext->DeviceExt,
1025                                            &SystemTime, &Fcb->entry.Fat.UpdateDate,
1026                                            &Fcb->entry.Fat.UpdateTime);
1027                 Fcb->entry.Fat.AccessDate = Fcb->entry.Fat.UpdateDate;
1028             }
1029             /* set date and times to dirty */
1030             Fcb->Flags |= FCB_IS_DIRTY;
1031
1032             /* Time to notify the OS */
1033             Filter = FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_ATTRIBUTES;
1034             if (ByteOffset.QuadPart != OldFileSize.QuadPart) Filter |= FILE_NOTIFY_CHANGE_SIZE;
1035
1036             FsRtlNotifyFullReportChange(IrpContext->DeviceExt->NotifySync,
1037                                         &(IrpContext->DeviceExt->NotifyList),
1038                                         (PSTRING)&Fcb->PathNameU,
1039                                         Fcb->PathNameU.Length - Fcb->LongNameU.Length,
1040                                         NULL,
1041                                         NULL,
1042                                         Filter,
1043                                         FILE_ACTION_MODIFIED,
1044                                         NULL);
1045         }
1046     }
1047
1048 ByeBye:
1049     if (Resource)
1050     {
1051         ExReleaseResourceLite(Resource);
1052     }
1053
1054     if (Status == STATUS_PENDING)
1055     {
1056         Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
1057         if (NT_SUCCESS(Status))
1058         {
1059             Status = VfatMarkIrpContextForQueue(IrpContext);
1060         }
1061     }
1062     else
1063     {
1064         IrpContext->Irp->IoStatus.Status = Status;
1065         if (IrpContext->FileObject->Flags & FO_SYNCHRONOUS_IO &&
1066             !(IrpContext->Irp->Flags & IRP_PAGING_IO) && NT_SUCCESS(Status))
1067         {
1068             IrpContext->FileObject->CurrentByteOffset.QuadPart =
1069                 ByteOffset.QuadPart + IrpContext->Irp->IoStatus.Information;
1070         }
1071
1072         if (NT_SUCCESS(Status))
1073             IrpContext->PriorityBoost = IO_DISK_INCREMENT;
1074     }
1075     DPRINT("%x\n", Status);
1076     return Status;
1077 }