Sample Code
windows driver samples/ cdfs file system driver/ C++/ verfysup.c/
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 | /*++ Copyright (c) 1989-2000 Microsoft Corporation Module Name: VerfySup.c Abstract: This module implements the Cdfs Verification routines. --*/ #include "CdProcs.h" // // The Bug check file id for this module // #define BugCheckFileId (CDFS_BUG_CHECK_VERFYSUP) #ifdef ALLOC_PRAGMA #pragma alloc_text(PAGE, CdVerifyFcbOperation) #pragma alloc_text(PAGE, CdVerifyVcb) #endif _Requires_lock_held_(_Global_critical_region_) NTSTATUS CdPerformVerify ( _Inout_ PIRP_CONTEXT IrpContext, _Inout_ PIRP Irp, _In_ PDEVICE_OBJECT DeviceToVerify ) /*++ Routine Description: This routines performs an IoVerifyVolume operation and takes the appropriate action. If the verify is successful then we send the originating Irp off to an Ex Worker Thread. This routine is called from the exception handler. No file system resources are held when this routine is called. Arguments: Irp - The irp to send off after all is well and done. Device - The real device needing verification. Return Value: None. --*/ { PVCB Vcb; NTSTATUS Status = STATUS_SUCCESS; PIO_STACK_LOCATION IrpSp; ASSERT_IRP_CONTEXT( IrpContext ); ASSERT_IRP( Irp ); // // Check if this Irp has a status of Verify required and if it does // then call the I/O system to do a verify. // // Skip the IoVerifyVolume if this is a mount or verify request // itself. Trying a recursive mount will cause a deadlock with // the DeviceObject->DeviceLock. // if ((IrpContext->MajorFunction == IRP_MJ_FILE_SYSTEM_CONTROL) && ((IrpContext->MinorFunction == IRP_MN_MOUNT_VOLUME) || (IrpContext->MinorFunction == IRP_MN_VERIFY_VOLUME))) { return CdFsdPostRequest( IrpContext, Irp ); } // // Extract a pointer to the Vcb from the VolumeDeviceObject. // Note that since we have specifically excluded mount, // requests, we know that IrpSp->DeviceObject is indeed a // volume device object. // IrpSp = IoGetCurrentIrpStackLocation( Irp ); Vcb = &CONTAINING_RECORD( IrpSp->DeviceObject, VOLUME_DEVICE_OBJECT, DeviceObject )->Vcb; try { // // Send down the verify FSCTL. Note that this is sent to the // currently mounted volume, which may not be this one. // // We will allow Raw to mount this volume if we were doing a // an absolute DASD open. // Status = IoVerifyVolume( DeviceToVerify, CdOperationIsDasdOpen( IrpContext)); // // Acquire the Vcb so we're working with a stable VcbCondition. // CdAcquireVcbShared( IrpContext, Vcb, FALSE); // // If the verify operation completed it will return // either STATUS_SUCCESS or STATUS_WRONG_VOLUME, exactly. // // If CdVerifyVolume encountered an error during // processing, it will return that error. If we got // STATUS_WRONG_VOLUME from the verify, and our volume // is now mounted, commute the status to STATUS_SUCCESS. // if ((Status == STATUS_WRONG_VOLUME) && (Vcb->VcbCondition == VcbMounted)) { Status = STATUS_SUCCESS; } else if ((STATUS_SUCCESS == Status) && (Vcb->VcbCondition != VcbMounted)) { // // If the verify succeeded, but our volume is not mounted, // then some other volume is on the device. // Status = STATUS_WRONG_VOLUME; } // // Do a quick unprotected check here. The routine will do // a safe check. After here we can release the resource. // Note that if the volume really went away, we will be taking // the Reparse path. // // // If the device might need to go away then call our dismount routine. // if (((Vcb->VcbCondition == VcbNotMounted) || (Vcb->VcbCondition == VcbInvalid) || (Vcb->VcbCondition == VcbDismountInProgress)) && (Vcb->VcbReference <= CDFS_RESIDUAL_REFERENCE)) { CdReleaseVcb( IrpContext, Vcb); CdAcquireCdData( IrpContext ); CdCheckForDismount( IrpContext, Vcb, FALSE ); CdReleaseCdData( IrpContext ); } else { CdReleaseVcb( IrpContext, Vcb); } // // If this is a create and the verify succeeded then complete the // request with a REPARSE status. // if ((IrpContext->MajorFunction == IRP_MJ_CREATE) && (IrpSp->FileObject->RelatedFileObject == NULL) && ((Status == STATUS_SUCCESS) || (Status == STATUS_WRONG_VOLUME))) { Irp->IoStatus.Information = IO_REMOUNT; CdCompleteRequest( IrpContext, Irp, STATUS_REPARSE ); Status = STATUS_REPARSE; Irp = NULL; IrpContext = NULL; // // If there is still an error to process then call the Io system // for a popup. // } else if ((Irp != NULL) && !NT_SUCCESS( Status )) { // // Fill in the device object if required. // if (IoIsErrorUserInduced( Status ) ) { IoSetHardErrorOrVerifyDevice( Irp, DeviceToVerify ); } CdNormalizeAndRaiseStatus( IrpContext, Status ); } // // If there is still an Irp, send it off to an Ex Worker thread. // if (IrpContext != NULL) { Status = CdFsdPostRequest( IrpContext, Irp ); } } except(CdExceptionFilter( IrpContext, GetExceptionInformation() )) { // // We had some trouble trying to perform the verify or raised // an error ourselves. So we'll abort the I/O request with // the error status that we get back from the execption code. // Status = CdProcessException( IrpContext, Irp, GetExceptionCode() ); } return Status; }
_Requires_lock_held_(_Global_critical_region_) BOOLEAN CdCheckForDismount ( _In_ PIRP_CONTEXT IrpContext, _Inout_ PVCB Vcb, _In_ BOOLEAN Force ) /*++ Routine Description: This routine is called to check if a volume is ready for dismount. This occurs when only file system references are left on the volume. If the dismount is not currently underway and the user reference count has gone to zero then we can begin the dismount. If the dismount is in progress and there are no references left on the volume (we check the Vpb for outstanding references as well to catch any create calls dispatched to the file system) then we can delete the Vcb. Arguments: Vcb - Vcb for the volume to try to dismount. Force - Whether we will force this volume to be dismounted. Return Value: BOOLEAN - True if the Vcb was not gone by the time this function finished, False if it was deleted. This is only a trustworthy indication to the caller if it had the vcb exclusive itself. --*/ { BOOLEAN UnlockVcb = TRUE; BOOLEAN VcbPresent = TRUE; KIRQL SavedIrql; ASSERT_IRP_CONTEXT( IrpContext ); ASSERT_VCB( Vcb ); ASSERT_EXCLUSIVE_CDDATA; // // Acquire and lock this Vcb to check the dismount state. // CdAcquireVcbExclusive( IrpContext, Vcb, FALSE ); // // Lets get rid of any pending closes for this volume. // CdFspClose( Vcb ); CdLockVcb( IrpContext, Vcb ); // // If the dismount is not already underway then check if the // user reference count has gone to zero or we are being forced // to disconnect. If so start the teardown on the Vcb. // if (Vcb->VcbCondition != VcbDismountInProgress) { if (Vcb->VcbUserReference <= CDFS_RESIDUAL_USER_REFERENCE || Force) { CdUnlockVcb( IrpContext, Vcb ); UnlockVcb = FALSE; VcbPresent = CdDismountVcb( IrpContext, Vcb ); } // // If the teardown is underway and there are absolutely no references // remaining then delete the Vcb. References here include the // references in the Vcb and Vpb. // } else if (Vcb->VcbReference == 0) { IoAcquireVpbSpinLock( &SavedIrql ); // // If there are no file objects and no reference counts in the // Vpb we can delete the Vcb. Don't forget that we have the // last reference in the Vpb. // if (Vcb->Vpb->ReferenceCount == 1) { IoReleaseVpbSpinLock( SavedIrql ); CdUnlockVcb( IrpContext, Vcb ); UnlockVcb = FALSE; CdDeleteVcb( IrpContext, Vcb ); VcbPresent = FALSE; } else { IoReleaseVpbSpinLock( SavedIrql ); } } // // Unlock the Vcb if still held. // if (UnlockVcb) { CdUnlockVcb( IrpContext, Vcb ); } // // Release any resources still acquired. // if (VcbPresent) { CdReleaseVcb( IrpContext, Vcb ); } else { _Analysis_assume_lock_not_held_(Vcb->VcbResource); } return VcbPresent; } BOOLEAN CdMarkDevForVerifyIfVcbMounted ( _Inout_ PVCB Vcb ) /*++ Routine Description: This routine checks to see if the specified Vcb is currently mounted on the device or not. If it is, it sets the verify flag on the device, if not then the state is noted in the Vcb. Arguments: Vcb - This is the volume to check. Return Value: TRUE if the device has been marked for verify here, FALSE otherwise. --*/ { BOOLEAN Marked = FALSE; KIRQL SavedIrql; IoAcquireVpbSpinLock( &SavedIrql ); #pragma prefast(suppress: 28175, "this is a filesystem driver, touching the vpb is allowed") if (Vcb->Vpb->RealDevice->Vpb == Vcb->Vpb) { CdMarkRealDevForVerify( Vcb->Vpb->RealDevice); Marked = TRUE; } else { // // Flag this to avoid the VPB spinlock in future passes. // SetFlag( Vcb->VcbState, VCB_STATE_VPB_NOT_ON_DEVICE); } IoReleaseVpbSpinLock( SavedIrql ); return Marked; } VOID CdVerifyVcb ( _In_ PIRP_CONTEXT IrpContext, _Inout_ PVCB Vcb ) /*++ Routine Description: This routine checks that the current Vcb is valid and currently mounted on the device. It will raise on an error condition. We check whether the volume needs verification and the current state of the Vcb. Arguments: Vcb - This is the volume to verify. Return Value: None --*/ { NTSTATUS Status = STATUS_SUCCESS; IO_STATUS_BLOCK Iosb; ULONG MediaChangeCount = 0; BOOLEAN ForceVerify = FALSE; BOOLEAN DevMarkedForVerify; PAGED_CODE(); // // Fail immediately if the volume is in the progress of being dismounted // or has been marked invalid. // if ((Vcb->VcbCondition == VcbInvalid) || ((Vcb->VcbCondition == VcbDismountInProgress) && (IrpContext->MajorFunction != IRP_MJ_CREATE))) { if (FlagOn( Vcb->VcbState, VCB_STATE_DISMOUNTED )) { CdRaiseStatus( IrpContext, STATUS_VOLUME_DISMOUNTED ); } else { CdRaiseStatus( IrpContext, STATUS_FILE_INVALID ); } } // // Capture the real device verify state. // DevMarkedForVerify = CdRealDevNeedsVerify( Vcb->Vpb->RealDevice); if (FlagOn( Vcb->VcbState, VCB_STATE_REMOVABLE_MEDIA ) && !DevMarkedForVerify) { // // If the media is removable and the verify volume flag in the // device object is not set then we want to ping the device // to see if it needs to be verified. // if (Vcb->VcbCondition != VcbMountInProgress) { Status = CdPerformDevIoCtrl( IrpContext, IOCTL_CDROM_CHECK_VERIFY, Vcb->TargetDeviceObject, &MediaChangeCount, sizeof ( ULONG ), FALSE, FALSE, &Iosb ); if (Iosb.Information != sizeof ( ULONG )) { // // Be safe about the count in case the driver didn't fill it in // MediaChangeCount = 0; } // // There are four cases when we want to do a verify. These are the // first three. // // 1. We are mounted, and the device has become empty // 2. The device has returned verify required (=> DO_VERIFY_VOL flag is // set, but could be due to hardware condition) // 3. Media change count doesn't match the one in the Vcb // if (((Vcb->VcbCondition == VcbMounted) && CdIsRawDevice( IrpContext, Status )) || (Status == STATUS_VERIFY_REQUIRED) || (NT_SUCCESS(Status) && (Vcb->MediaChangeCount != MediaChangeCount))) { // // If we are currently the volume on the device then it is our // responsibility to set the verify flag. If we're not on the device, // then we shouldn't touch the flag. // if (!FlagOn( Vcb->VcbState, VCB_STATE_VPB_NOT_ON_DEVICE) && !DevMarkedForVerify) { DevMarkedForVerify = CdMarkDevForVerifyIfVcbMounted( Vcb); } ForceVerify = TRUE; // // NOTE that we no longer update the media change count here. We // do so only when we've actually completed a verify at a particular // change count value. // } } // // This is the 4th verify case. // // We ALWAYS force CREATE requests on unmounted volumes through the // verify path. These requests could have been in limbo between // IoCheckMountedVpb and us when a verify/mount took place and caused // a completely different fs/volume to be mounted. In this case the // checks above may not have caught the condition, since we may already // have verified (wrong volume) and decided that we have nothing to do. // We want the requests to be re routed to the currently mounted volume, // since they were directed at the 'drive', not our volume. // if (NT_SUCCESS( Status) && !ForceVerify && !DevMarkedForVerify && (IrpContext->MajorFunction == IRP_MJ_CREATE)) { PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation( IrpContext->Irp); ForceVerify = (IrpSp->FileObject->RelatedFileObject == NULL) && ((Vcb->VcbCondition == VcbDismountInProgress) || (Vcb->VcbCondition == VcbNotMounted)); // // Note that we don't touch the device verify flag here. It required // it would have been caught and set by the first set of checks. // } } // // Raise the verify / error if neccessary. // if (ForceVerify || DevMarkedForVerify || !NT_SUCCESS( Status)) { IoSetHardErrorOrVerifyDevice( IrpContext->Irp, Vcb->Vpb->RealDevice ); CdRaiseStatus( IrpContext, (ForceVerify || DevMarkedForVerify) ? STATUS_VERIFY_REQUIRED : Status); } // // Based on the condition of the Vcb we'll either return to our // caller or raise an error condition // switch (Vcb->VcbCondition) { case VcbNotMounted: IoSetHardErrorOrVerifyDevice( IrpContext->Irp, Vcb->Vpb->RealDevice ); CdRaiseStatus( IrpContext, STATUS_WRONG_VOLUME ); break ; case VcbInvalid: case VcbDismountInProgress: if (FlagOn( Vcb->VcbState, VCB_STATE_DISMOUNTED )) { CdRaiseStatus( IrpContext, STATUS_VOLUME_DISMOUNTED ); } else { CdRaiseStatus( IrpContext, STATUS_FILE_INVALID ); } break ; } } BOOLEAN CdVerifyFcbOperation ( _In_opt_ PIRP_CONTEXT IrpContext, _In_ PFCB Fcb ) /*++ Routine Description: This routine is called to verify that the state of the Fcb is valid to allow the current operation to continue. We use the state of the Vcb, target device and type of operation to determine this. Arguments: IrpContext - IrpContext for the request. If not present then we were called from the fast IO path. Fcb - Fcb to perform the request on. Return Value: BOOLEAN - TRUE if the request can continue, FALSE otherwise. --*/ { PVCB Vcb = Fcb->Vcb; PDEVICE_OBJECT RealDevice = Vcb->Vpb->RealDevice; PIRP Irp; PAGED_CODE(); // // Check that the fileobject has not been cleaned up. // if ( ARGUMENT_PRESENT( IrpContext )) { PFILE_OBJECT FileObject; Irp = IrpContext->Irp; FileObject = IoGetCurrentIrpStackLocation( Irp)->FileObject; if ( FileObject && FlagOn( FileObject->Flags, FO_CLEANUP_COMPLETE)) { PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation( Irp ); // // Following FAT, we allow certain operations even on cleaned up // file objects. Everything else, we fail. // if ( (FlagOn(Irp->Flags, IRP_PAGING_IO)) || (IrpSp->MajorFunction == IRP_MJ_CLOSE ) || (IrpSp->MajorFunction == IRP_MJ_QUERY_INFORMATION) || ( (IrpSp->MajorFunction == IRP_MJ_READ) && FlagOn(IrpSp->MinorFunction, IRP_MN_COMPLETE) ) ) { NOTHING; } else { CdRaiseStatus( IrpContext, STATUS_FILE_CLOSED ); } } } // // Fail immediately if the volume is in the progress of being dismounted // or has been marked invalid. // if ((Vcb->VcbCondition == VcbInvalid) || (Vcb->VcbCondition == VcbDismountInProgress)) { if (ARGUMENT_PRESENT( IrpContext )) { if (FlagOn( Vcb->VcbState, VCB_STATE_DISMOUNTED )) { CdRaiseStatus( IrpContext, STATUS_VOLUME_DISMOUNTED ); } else { CdRaiseStatus( IrpContext, STATUS_FILE_INVALID ); } } return FALSE; } // // Always fail if the volume needs to be verified. // if (CdRealDevNeedsVerify( RealDevice)) { if (ARGUMENT_PRESENT( IrpContext )) { IoSetHardErrorOrVerifyDevice( IrpContext->Irp, RealDevice ); CdRaiseStatus( IrpContext, STATUS_VERIFY_REQUIRED ); } return FALSE; // // // All operations are allowed on mounted. // } else if ((Vcb->VcbCondition == VcbMounted) || (Vcb->VcbCondition == VcbMountInProgress)) { return TRUE; // // Fail all requests for fast Io on other Vcb conditions. // } else if (!ARGUMENT_PRESENT( IrpContext )) { return FALSE; // // The remaining case is VcbNotMounted. // Mark the device to be verified and raise WRONG_VOLUME. // } else if (Vcb->VcbCondition == VcbNotMounted) { IoSetHardErrorOrVerifyDevice( IrpContext->Irp, RealDevice ); CdRaiseStatus( IrpContext, STATUS_WRONG_VOLUME ); // return FALSE; // unreachable code } return TRUE; }
_Requires_lock_held_(_Global_critical_region_) BOOLEAN CdDismountVcb ( _In_ PIRP_CONTEXT IrpContext, _Inout_ PVCB Vcb ) /*++ Routine Description: This routine is called when all of the user references to a volume are gone. We will initiate all of the teardown any system resources. If all of the references to this volume are gone at the end of this routine then we will complete the teardown of this Vcb and mark the current Vpb as not mounted. Otherwise we will allocated a new Vpb for this device and keep the current Vpb attached to the Vcb. Arguments: Vcb - Vcb for the volume to dismount. Return Value: BOOLEAN - TRUE if we didn't delete the Vcb, FALSE otherwise. --*/ { PVPB OldVpb; BOOLEAN VcbPresent = TRUE; KIRQL SavedIrql; BOOLEAN FinalReference; ASSERT_EXCLUSIVE_CDDATA; ASSERT_EXCLUSIVE_VCB( Vcb ); CdLockVcb( IrpContext, Vcb ); // // We should only take this path once. // NT_ASSERT( Vcb->VcbCondition != VcbDismountInProgress ); // // Mark the Vcb as DismountInProgress. // Vcb->VcbCondition = VcbDismountInProgress; if (Vcb->XASector != NULL) { CdFreePool( &Vcb->XASector ); Vcb->XASector = 0; Vcb->XADiskOffset = 0; } // // Remove our reference to the internal Fcb's. The Fcb's will then // be removed in the purge path below. // if (Vcb->RootIndexFcb != NULL) { Vcb->RootIndexFcb->FcbReference -= 1; Vcb->RootIndexFcb->FcbUserReference -= 1; } if (Vcb->PathTableFcb != NULL) { Vcb->PathTableFcb->FcbReference -= 1; Vcb->PathTableFcb->FcbUserReference -= 1; } if (Vcb->VolumeDasdFcb != NULL) { Vcb->VolumeDasdFcb->FcbReference -= 1; Vcb->VolumeDasdFcb->FcbUserReference -= 1; } CdUnlockVcb( IrpContext, Vcb ); // // Purge the volume. // CdPurgeVolume( IrpContext, Vcb, TRUE ); // // Empty the delayed and async close queues. // CdFspClose( Vcb ); OldVpb = Vcb->Vpb; // // Remove the mount volume reference. // CdLockVcb( IrpContext, Vcb ); Vcb->VcbReference -= 1; // // Acquire the Vpb spinlock to check for Vpb references. // IoAcquireVpbSpinLock( &SavedIrql ); // // Remember if this is the last reference on this Vcb. We incremented // the count on the Vpb earlier so we get one last crack it. If our // reference has gone to zero but the vpb reference count is greater // than zero then the Io system will be responsible for deleting the // Vpb. // FinalReference = ( BOOLEAN ) ((Vcb->VcbReference == 0) && (OldVpb->ReferenceCount == 1)); // // There is a reference count in the Vpb and in the Vcb. We have // incremented the reference count in the Vpb to make sure that // we have last crack at it. If this is a failed mount then we // want to return the Vpb to the IO system to use for the next // mount request. // #pragma prefast(suppress: 28175, "this is a filesystem driver, touching the vpb is allowed") if (OldVpb->RealDevice->Vpb == OldVpb) { // // If not the final reference then swap out the Vpb. We must // preserve the REMOVE_PENDING flag so that the device is // not remounted in the middle of a PnP remove operation. // if (!FinalReference) { NT_ASSERT( Vcb->SwapVpb != NULL ); Vcb->SwapVpb->Type = IO_TYPE_VPB; Vcb->SwapVpb->Size = sizeof ( VPB ); #pragma prefast(push) #pragma prefast(disable: 28175, "this is a filesystem driver, touching the vpb is allowed") Vcb->SwapVpb->RealDevice = OldVpb->RealDevice; Vcb->SwapVpb->RealDevice->Vpb = Vcb->SwapVpb; #pragma prefast(pop) Vcb->SwapVpb->Flags = FlagOn( OldVpb->Flags, VPB_REMOVE_PENDING ); IoReleaseVpbSpinLock( SavedIrql ); // // Indicate we used up the swap. // Vcb->SwapVpb = NULL; CdUnlockVcb( IrpContext, Vcb ); // // We want to leave the Vpb for the IO system. Mark it // as being not mounted. Go ahead and delete the Vcb as // well. // } else { // // Make sure to remove the last reference on the Vpb. // OldVpb->ReferenceCount -= 1; OldVpb->DeviceObject = NULL; ClearFlag( Vcb->Vpb->Flags, VPB_MOUNTED ); ClearFlag( Vcb->Vpb->Flags, VPB_LOCKED ); // // Clear the Vpb flag so we know not to delete it. // Vcb->Vpb = NULL; IoReleaseVpbSpinLock( SavedIrql ); CdUnlockVcb( IrpContext, Vcb ); CdDeleteVcb( IrpContext, Vcb ); VcbPresent = FALSE; } // // Someone has already swapped in a new Vpb. If this is the final reference // then the file system is responsible for deleting the Vpb. // } else if (FinalReference) { // // Make sure to remove the last reference on the Vpb. // OldVpb->ReferenceCount -= 1; IoReleaseVpbSpinLock( SavedIrql ); CdUnlockVcb( IrpContext, Vcb ); CdDeleteVcb( IrpContext, Vcb ); VcbPresent = FALSE; // // The current Vpb is no longer the Vpb for the device (the IO system // has already allocated a new one). We leave our reference in the // Vpb and will be responsible for deleting it at a later time. // } else { IoReleaseVpbSpinLock( SavedIrql ); CdUnlockVcb( IrpContext, Vcb ); } // // Let our caller know whether the Vcb is still present. // return VcbPresent; } |
Our Services
-
What our customers say about us?
Read our customer testimonials to find out why our clients keep returning for their projects.
View Testimonials