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That was the idea behind using posix_lock_file, and I sent a patch to do that, too. Chaskiel's enroll patch is effectively the same, pre cleanup (but cleaner). I didn't foresee the issues that arose, either. I did test a few 2.4.x kernels, and 2.6.9, with overlapping and non overlapping ranges, local and remote locks in AFS. Things got more complicated on the Linux side, I guess. For future, we want unified behavior across platforms. Then, there is server side byte-range locking... Matt Christopher Allen Wing wrote: > Marcus: > > > On Thu, 8 Feb 2007, Marcus Watts wrote: > > > I think the current semantics (as of 1.4.2+) are a mishmash of > traditional AFS locking plus partial local locking in some cases. It's > not consistent. > >> I believe Matt is planning to produce a much more extensive >> "portable" version of locking that should work much like the >> current linux code is supposed to work (ie, local byte range locks >> layered on top of fileserver whole file locks) that should work for >> most unix(-like) platforms. > > I think it would be possible to do something like this on linux by > primarily using the local linux locking code, and having a helper > function that attempts to change the lock state on the AFS server to: > > single read lock > single write lock > no lock > > upon request. But it seems there aren't reliable means to do this. > There is no race-free way to transition between a read lock and write > lock and vice versa. If there is an extended network failure any lock > on the server will time out and then, potentially, local locks might > remain in place- do we then have to call back into the kernel and kill > all the local locks? > > > I don't know what type of kernel APIs are available on other types of > unix. It would be nice if we didn't have to rewrite an entire posix > file locking layer in openafs, but rather, re-use kernel APIs where > possible. > > > -Chris > [EMAIL PROTECTED] > _______________________________________________ > OpenAFS-devel mailing list > [email protected] > https://lists.openafs.org/mailman/listinfo/openafs-devel - -- Matt Benjamin The Linux Box 206 South Fifth Ave. Suite 150 Ann Arbor, MI 48104 http://linuxbox.com tel. 734-761-4689 fax. 734-769-8938 cel. 734-216-5309 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFy4q5JiSUUSaRdSURCNoMAJ9/L9UvKHH3kyvPCfwcUFI5vsFllwCfWF2Z MZoVF21urXEH97xgXHa3qKw= =5UVk -----END PGP SIGNATURE----- _______________________________________________ OpenAFS-devel mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-devel
