Vivek Verma <mailto:vivek_ve...@apple.com>
April 3, 2018 at 11:46 AM
Advisory locking as defined by POSIX is bunch of sentences thrown
together which make no sense when you actually try to use it in a real
world application.
AFP's locking protocol
(https://developer.apple.com/library/content/documentation/Networking/Conceptual/AFP/UsingForkCommands/UsingForkCommands.html#//apple_ref/doc/uid/TP40000854-CH225-SW1)
borrows some API elements (on macOS) from the advisory locking
interfaces , so some calls may on the surface appear to work the same
but it does _not_ completely support POSIX style advisory locking and
that's why the macOS AFP client does not claim to support it. It has
its own locking implementation which interface-wise may overlap a bit
with the interfaces for advisory locking.
I appreciate this position, and I'm aware that POSIX locking has some
holes. I also appreciate that AFP mandatory locking and POSIX file
locking are not interchangeable and therefor AFP can't claim to support
them.
However, at the end of the day, I really just want to find out what
works and get some rudimentary understanding as to why and what the
pitfalls are / might be.
I have a real issue with file corruption from multiple clients writing
to the same set of database files/package. All of my code has been
re-written to use the POSIX API (i.e. open(2) et al). If the POSIX API
bridges to the AFP file locking mechanism on afpfs volumes in any
predictable way—and I can deal with some inconsistencies—that would be
really good news for my application.
I've already got POSIX file locking and advisory locking, via fcntl(2),
to work. Getting any kind of locking on AFP volumes is the last big hole
I want to fill.
James
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Filesystem-dev mailing list (Filesystem-dev@lists.apple.com)
Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/filesystem-dev/archive%40mail-archive.com
This email sent to arch...@mail-archive.com
