MacOS Ventura, compounded flush and close, and io_uring woes

[Stefan Metzmacher]

Hi Andrew,

> I have two questions regarding this:
> 
> 1) Are we sure this is the correct behavior vis-a-vis compounded requests?
> C.F.  MS-SMB2 note:
> https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/a64e55aa-1152-48e4-8206-edd96444e7f7#Appendix_A_245
> ```
> <245> Section 3.3.5.2.7: In Windows Vista and Windows Server 2008, when an
> operation in a compound request requires asynchronous processing,
> Windows-based servers fail them with STATUS_INTERNAL_ERROR except for the
> following two cases: when a create request in the compound request triggers
> an oplock break, or when the operation is last in the compound request.
> ```
> The above appears to be something specific to Windows Vista and Server 2008.

See https://bugzilla.samba.org/show_bug.cgi?id=15172

> 2) Has anyone been working towards adding a more granular cancellation
> mechanism for vfs_io_uring?

I'm currently reworking our io_uring integration,
which will make it easier to use IORING_OP_ASYNC_CANCEL and/or
IORING_REGISTER_SYNC_CANCEL.

metze