Enhancement: Support for FILE_SUPPORTS_POSIX_UNLINK_RENAME

billziss-gh commented 3 years ago

As per title.

billziss-gh commented 3 years ago

Preliminary notes for implementation. These notes may be incomplete, inaccurate or plain old wrong. May be updated as implementation progresses.

Header changes

[x] fsctl.h:
- [x] FSP_FSCTL_VOLUME_PARAMS_V0_FIELD_DEFN:
  - [x] Add SupportsPosixUnlinkRename:1
  - [ ] Add CleanupResultInfo:1
  - [ ] Add PostCleanupOnDeleteOnly:1. Can we implement this?
  - [x] Change KmReservedFlags:3 to KmReservedFlags:1 or delete (depending on PostCleanupOnDeleteOnly feasibility).
  - [ ] Likely we should unify SupportsPosixUnlinkRename and CleanupResultInfo.
- [x] FSP_FSCTL_TRANSACT_REQ:
  - [x] add SetInformation.DispositionEx
  - [x] add SetInformation.RenameEx

[x] winfsp.h: Add FSP_FILE_SYSTEM_INTERFACE::Delete.

[x] Delete supersedes CanDelete and SetDelete when available.

[x] File system implementation should look like:

NTSTATUS Delete(FSP_FILE_SYSTEM *FileSystem,
    PVOID FileContext, PWSTR FileName, ULONG Flags)
{
    switch (Flags)
    {
    case FILE_DISPOSITION_DO_NOT_DELETE:
        // set file disposition flag: do not delete file at Cleanup
        return STATUS_SUCCESS;
    case FILE_DISPOSITION_DELETE:
        // set file disposition flag: delete file at Cleanup
        return STATUS_SUCCESS;
    case FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS:
        // delete file now; open handles to file remain valid
        return STATUS_SUCCESS;
    case (ULONG)-1:
        // delete file now; called during Cleanup
        return STATUS_SUCCESS;
    default:
        return STATUS_INVALID_PARAMETER;
    }
}

FSD changes

[x] FspFsvolQueryFsAttributeInformation: add FILE_SUPPORTS_POSIX_UNLINK_RENAME
[x] FspFsvolSetInformation: add FileDispositionInformationEx and FileRenameInformationEx.
[x] FspFsvolSetInformationComplete: add FileDispositionInformationEx and FileRenameInformationEx.
[x] FspFsvolSetDispositionInformation: modified to support FileDispositionInformation and FileDispositionInformationEx.
- [x] FileDispositionInformationEx: should only pass along FILE_DISPOSITION_DO_NOT_DELETE, FILE_DISPOSITION_DELETE, FILE_DISPOSITION_POSIX_SEMANTICS, FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE. Other flags should be handled internally by FSD.
  - [x] FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE: should be pruned if FileDesc->GrantedAccess does not have FILE_WRITE_ATTRIBUTES.
  - [x] FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK: should perform the MmFlushImageSection check.
  - [ ] FILE_DISPOSITION_ON_CLOSE: ?
[x] FspFsvolSetDispositionInformationSuccess: how to handle additional FILE_DISPOSITION_* cases here?
- [x] When doing POSIX delete, we should post all delete notifications that FspFsvolCleanupComplete posts when deleting.
- [x] When doing POSIX delete, we should remove the file from the Context table.
[x] FspFileNodeRename: what changes are required for rename here?
[ ] FspFsvolCleanup: determine if possible to implement the PostCleanupOnDeleteOnly optimization flag.
- [ ] Main obstacle is the metadata notifications done in FspFsvolCleanupComplete.
[ ] FspFsvolCleanupComplete:
- [ ] Support FILE_CLEANUP_* flags when CleanupResultInfo.
  - [ ] Alternatively we can have WinFsp always claim that FILE_RETURNS_CLEANUP_RESULT_INFO.
  - [ ] When doing POSIX delete, do not post delete notifications.
[x] FspFileNodeCleanupComplete:
- [x] When doing POSIX delete, do no remove the file from the Context table as it was already removed by FspFsvolSetDispositionInformationSuccess.
[ ] FspIopCompleteIrpEx: allow Irp->IoStatus.Information != 0 for IRP_MJ_CLEANUP.
[x] Debug dumps for FileDispositionInformationEx and FileRenameInformationEx.

DLL changes

[x] FspFileSystemOpEnter and FspFileSystemOpLeave.
[x] FspFileSystemOpSetInformation: modified to support FileDispositionInformation and FileDispositionInformationEx.
- [x] FileDispositionInformationEx: FILE_ATTRIBUTE_READONLY check should be skipped if FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE is set. The FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE flag should be pruned.
- [x] Delete: Delete supersedes CanDelete and SetDelete if available.
[x] FspFileSystemOpCleanup: modified to call Delete(-1) on Request->Req.Cleanup.Delete.
- [ ] Delete result should be converted to FILE_CLEANUP_* codes and passed to Response->IoStatus.Information.
[x] Debug dumps for FileDispositionInformationEx and FileRenameInformationEx.

FUSE

[x] SupportsPosixUnlinkRename, CleanupResultInfo, PostCleanupOnDeleteOnly should be enabled in the FUSE layer.
[x] fsp_fuse_op_enter_lock and fsp_fuse_op_leave_unlock.
[x] Delete call added that does unlink or rmdir accordingly.
[x] Cleanup can be removed.

.NET

[x] Support to add flags such as SupportsPosixUnlinkRename, etc.
[x] Delete should be added.

Testing

[x] memfs: use new Delete protocol
[x] memfs: add MemfsLegacyUnlinkRename
[x] winfsp-tests: add -legacy-unlink-rename option

billziss-gh commented 3 years ago

Related commits (experimental):

Commit 19823d84de16a144d6ea8e5b013e059f645737f3: sys,dll,inc: implement new Delete design and POSIX semantics
Commit a4d7aee6f5c9070cbf517d78f320bbb266698ef1: dll: fuse: implement new Delete design and POSIX semantics
Commit 76bfa395a8ce50302aa679895c7165a689b6b5e8: dotnet: implement new Delete design and POSIX semantics
Commit bb3e92df6c971dbd93c3475757e6386c01036980: sys, dll: implement POSIX semantics for Rename
Commit 9eaaefd15496d432728aeb24fac93f245888b9c3: sys,dll: debug support for DispositionEx, RenameEx

billziss-gh commented 2 years ago

This functionality has been implemented and is available in WinFsp 2021.1 Beta3.

winfsp / winfsp