rw.c

winNT技术操作系统,国外开放的原代码和LIUX一样

      }
/**/
      if (NT_SUCCESS(Status))
      {
         IrpContext->Irp->IoStatus.Information = ReturnedLength;
      }
   }

ByeBye:
   if (Resource)
   {
      ExReleaseResourceLite(Resource);
   }

   if (Status == STATUS_PENDING)
   {
      Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoWriteAccess);
      if (NT_SUCCESS(Status))
      {
         Status = VfatQueueRequest(IrpContext);
      }
      else
      {
         IrpContext->Irp->IoStatus.Status = Status;
         IoCompleteRequest(IrpContext->Irp, IO_NO_INCREMENT);
         VfatFreeIrpContext(IrpContext);
      }
   }
   else
   {
      IrpContext->Irp->IoStatus.Status = Status;
      if (IrpContext->FileObject->Flags & FO_SYNCHRONOUS_IO &&
          !(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
          (NT_SUCCESS(Status) || Status==STATUS_END_OF_FILE))
      {
         IrpContext->FileObject->CurrentByteOffset.QuadPart =
           ByteOffset.QuadPart + IrpContext->Irp->IoStatus.Information;
      }

      IoCompleteRequest(IrpContext->Irp,
                        (CCHAR)(NT_SUCCESS(Status) ? IO_DISK_INCREMENT : IO_NO_INCREMENT));
      VfatFreeIrpContext(IrpContext);
   }
   DPRINT("%x\n", Status);
   return Status;
}

NTSTATUS VfatWrite (PVFAT_IRP_CONTEXT IrpContext)
{
   PVFATFCB Fcb;
   PERESOURCE Resource = NULL;
   LARGE_INTEGER ByteOffset;
   LARGE_INTEGER OldFileSize;
   NTSTATUS Status = STATUS_SUCCESS;
   ULONG Length = 0;
   ULONG OldAllocationSize;
   PVOID Buffer;
   ULONG BytesPerSector;

   ASSERT(IrpContext);

   DPRINT("VfatWrite(IrpContext %x)\n", IrpContext);

   ASSERT(IrpContext->DeviceObject);

   // This request is not allowed on the main device object
   if (IrpContext->DeviceObject == VfatGlobalData->DeviceObject)
   {
      DPRINT("VfatWrite is called with the main device object.\n");
      Status = STATUS_INVALID_DEVICE_REQUEST;
      goto ByeBye;
   }

   ASSERT(IrpContext->DeviceExt);
   ASSERT(IrpContext->FileObject);
   Fcb = IrpContext->FileObject->FsContext;
   ASSERT(Fcb);

   DPRINT("<%wZ>\n", &Fcb->PathNameU);

   if (Fcb->Flags & FCB_IS_PAGE_FILE)
   {
      PFATINFO FatInfo = &IrpContext->DeviceExt->FatInfo;
      IrpContext->Stack->Parameters.Write.ByteOffset.QuadPart += FatInfo->dataStart * FatInfo->BytesPerSector;
      IoSkipCurrentIrpStackLocation(IrpContext->Irp);
      DPRINT("Write to page file, disk offset %I64x\n", IrpContext->Stack->Parameters.Write.ByteOffset.QuadPart);
      Status = IoCallDriver(IrpContext->DeviceExt->StorageDevice, IrpContext->Irp);
      VfatFreeIrpContext(IrpContext);
      return Status;
   }

  /* fail if file is a directory and no paged read */
   if (*Fcb->Attributes & FILE_ATTRIBUTE_DIRECTORY && !(IrpContext->Irp->Flags & IRP_PAGING_IO))
   {
      Status = STATUS_INVALID_PARAMETER;
      goto ByeBye;
   }

   ByteOffset = IrpContext->Stack->Parameters.Write.ByteOffset;
   if (ByteOffset.u.LowPart == FILE_WRITE_TO_END_OF_FILE &&
       ByteOffset.u.HighPart == -1)
   {
      ByteOffset.QuadPart = Fcb->RFCB.FileSize.QuadPart;
   }
   Length = IrpContext->Stack->Parameters.Write.Length;
   BytesPerSector = IrpContext->DeviceExt->FatInfo.BytesPerSector;

   if (ByteOffset.u.HighPart && !(Fcb->Flags & FCB_IS_VOLUME))
   {
      Status = STATUS_INVALID_PARAMETER;
      goto ByeBye;
   }

   if (Fcb->Flags & (FCB_IS_FAT | FCB_IS_VOLUME) ||
       1 == vfatDirEntryGetFirstCluster (IrpContext->DeviceExt, &Fcb->entry))
   {
      if (ByteOffset.QuadPart + Length > Fcb->RFCB.FileSize.QuadPart)
      {
         // we can't extend the FAT, the volume or the root on FAT12/FAT16
         Status = STATUS_END_OF_FILE;
         goto ByeBye;
      }
   }

   if (IrpContext->Irp->Flags & (IRP_PAGING_IO|IRP_NOCACHE) || (Fcb->Flags & FCB_IS_VOLUME))
   {
      if (ByteOffset.u.LowPart % BytesPerSector != 0 || Length % BytesPerSector != 0)
      {
         // non cached write must be sector aligned
         Status = STATUS_INVALID_PARAMETER;
         goto ByeBye;
      }
   }

   if (Length == 0)
   {
      /* FIXME:
       *   Update last write time
       */
      IrpContext->Irp->IoStatus.Information = 0;
      Status = STATUS_SUCCESS;
      goto ByeBye;
   }

   if (IrpContext->Irp->Flags & IRP_PAGING_IO)
   {
      if (ByteOffset.u.LowPart + Length > Fcb->RFCB.AllocationSize.u.LowPart)
      {
         Status = STATUS_INVALID_PARAMETER;
         goto ByeBye;
      }
      if (ByteOffset.u.LowPart + Length > ROUND_UP(Fcb->RFCB.AllocationSize.u.LowPart, BytesPerSector))
      {
         Length =  ROUND_UP(Fcb->RFCB.FileSize.u.LowPart, BytesPerSector) - ByteOffset.u.LowPart;
      }
   }

   if (Fcb->Flags & FCB_IS_VOLUME)
   {
      Resource = &IrpContext->DeviceExt->DirResource;
   }
   else if (IrpContext->Irp->Flags & IRP_PAGING_IO)
   {
      Resource = &Fcb->PagingIoResource;
   }
   else
   {
      Resource = &Fcb->MainResource;
   }

   if (Fcb->Flags & FCB_IS_PAGE_FILE)
   {
      if (!ExAcquireResourceSharedLite(Resource,
                                       (BOOLEAN)(IrpContext->Flags & IRPCONTEXT_CANWAIT)))
      {
         Resource = NULL;
         Status = STATUS_PENDING;
         goto ByeBye;
      }
   }
   else
   {
      if (!ExAcquireResourceExclusiveLite(Resource,
                                          (BOOLEAN)(IrpContext->Flags & IRPCONTEXT_CANWAIT)))
      {
         Resource = NULL;
         Status = STATUS_PENDING;
         goto ByeBye;
      }
   }

   if (!(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
      FsRtlAreThereCurrentFileLocks(&Fcb->FileLock))
   {
      if (!FsRtlCheckLockForWriteAccess(&Fcb->FileLock, IrpContext->Irp))
      {
         Status = STATUS_FILE_LOCK_CONFLICT;
         goto ByeBye;
       }
    }

   if (!(IrpContext->Flags & IRPCONTEXT_CANWAIT) && !(Fcb->Flags & FCB_IS_VOLUME))
   {
      if (ByteOffset.u.LowPart + Length > Fcb->RFCB.AllocationSize.u.LowPart)
      {
        Status = STATUS_PENDING;
        goto ByeBye;
      }
   }

   OldFileSize = Fcb->RFCB.FileSize;
   OldAllocationSize = Fcb->RFCB.AllocationSize.u.LowPart;

   Buffer = VfatGetUserBuffer(IrpContext->Irp);
   if (!Buffer)
     {
       Status = STATUS_INVALID_USER_BUFFER;
       goto ByeBye;
     }


   if (!(Fcb->Flags & (FCB_IS_FAT|FCB_IS_VOLUME)) &&
       !(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
       ByteOffset.u.LowPart + Length > Fcb->RFCB.FileSize.u.LowPart)
   {
      LARGE_INTEGER AllocationSize;
      AllocationSize.QuadPart = ByteOffset.u.LowPart + Length;
      Status = VfatSetAllocationSizeInformation(IrpContext->FileObject, Fcb,
	                                        IrpContext->DeviceExt, &AllocationSize);
      if (!NT_SUCCESS (Status))
      {
         CHECKPOINT;
         goto ByeBye;
      }
   }

   if (!(IrpContext->Irp->Flags & (IRP_NOCACHE|IRP_PAGING_IO)) &&
      !(Fcb->Flags & (FCB_IS_PAGE_FILE|FCB_IS_VOLUME)))
   {
      // cached write
      CHECKPOINT;

      if (IrpContext->FileObject->PrivateCacheMap == NULL)
      {
#ifdef USE_ROS_CC_AND_FS
         ULONG CacheSize;
         CacheSize = max(IrpContext->DeviceExt->FatInfo.BytesPerCluster,
                         8 * PAGE_SIZE);
	 CcRosInitializeFileCache(IrpContext->FileObject, CacheSize);
#else
         /* FIXME: Guard by SEH. */
         CcInitializeCacheMap(IrpContext->FileObject,
                              (PCC_FILE_SIZES)(&Fcb->RFCB.AllocationSize),
                              FALSE,
                              &VfatGlobalData->CacheMgrCallbacks,
                              Fcb);
#endif
      }
      if (ByteOffset.QuadPart > OldFileSize.QuadPart)
      {
         CcZeroData(IrpContext->FileObject, &OldFileSize, &ByteOffset, TRUE);
      }
      if (CcCopyWrite(IrpContext->FileObject, &ByteOffset, Length,
                      1 /*IrpContext->Flags & IRPCONTEXT_CANWAIT*/, Buffer))
      {
      	 IrpContext->Irp->IoStatus.Information = Length;
         Status = STATUS_SUCCESS;
      }
      else
      {
         Status = STATUS_UNSUCCESSFUL;
      }
      CHECKPOINT;
   }
   else
   {
      // non cached write
      CHECKPOINT;

      if (ByteOffset.QuadPart > OldFileSize.QuadPart)
      {
         CcZeroData(IrpContext->FileObject, &OldFileSize, &ByteOffset, TRUE);
      }

      Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
      if (!NT_SUCCESS(Status))
        {
	  goto ByeBye;
	}

      Status = VfatWriteFileData(IrpContext, Length, ByteOffset);
      if (NT_SUCCESS(Status))
      {
         IrpContext->Irp->IoStatus.Information = Length;
      }
   }

   if (!(IrpContext->Irp->Flags & IRP_PAGING_IO) &&
      !(Fcb->Flags & (FCB_IS_FAT|FCB_IS_VOLUME)))
   {
      if(!(*Fcb->Attributes & FILE_ATTRIBUTE_DIRECTORY))
      {
         LARGE_INTEGER SystemTime;
         // set dates and times
         KeQuerySystemTime (&SystemTime);
         if (Fcb->Flags & FCB_IS_FATX_ENTRY)
         {
            FsdSystemTimeToDosDateTime (IrpContext->DeviceExt,
                                     &SystemTime, &Fcb->entry.FatX.UpdateDate,
                                     &Fcb->entry.FatX.UpdateTime);
            Fcb->entry.FatX.AccessDate = Fcb->entry.FatX.UpdateDate;
            Fcb->entry.FatX.AccessTime = Fcb->entry.FatX.UpdateTime;
         }
         else
         {
            FsdSystemTimeToDosDateTime (IrpContext->DeviceExt,
                                     &SystemTime, &Fcb->entry.Fat.UpdateDate,
                                     &Fcb->entry.Fat.UpdateTime);
            Fcb->entry.Fat.AccessDate = Fcb->entry.Fat.UpdateDate;
         }
         /* set date and times to dirty */
	 Fcb->Flags |= FCB_IS_DIRTY;
      }
   }

ByeBye:
   if (Resource)
   {
      ExReleaseResourceLite(Resource);
   }

   if (Status == STATUS_PENDING)
   {
      Status = VfatLockUserBuffer(IrpContext->Irp, Length, IoReadAccess);
      if (NT_SUCCESS(Status))
      {
         Status = VfatQueueRequest(IrpContext);
      }
      else
      {
         IrpContext->Irp->IoStatus.Status = Status;
         IoCompleteRequest(IrpContext->Irp, IO_NO_INCREMENT);
         VfatFreeIrpContext(IrpContext);
      }
   }
   else
   {
      IrpContext->Irp->IoStatus.Status = Status;
      if (IrpContext->FileObject->Flags & FO_SYNCHRONOUS_IO &&
          !(IrpContext->Irp->Flags & IRP_PAGING_IO) && NT_SUCCESS(Status))
      {
         IrpContext->FileObject->CurrentByteOffset.QuadPart =
           ByteOffset.QuadPart + IrpContext->Irp->IoStatus.Information;
      }

      IoCompleteRequest(IrpContext->Irp,
                        (CCHAR)(NT_SUCCESS(Status) ? IO_DISK_INCREMENT : IO_NO_INCREMENT));
      VfatFreeIrpContext(IrpContext);
   }
   DPRINT("%x\n", Status);
   return Status;
}