Hi, On Thu, Apr 17, 2008 at 02:45:16PM -0700, Amit Singh wrote: > > Sorry, I was sure I remembered seeing some posts that indicated that > > direct_io > > ought to be avoided, but I'm having a hard time finding them now. > > I think it was more like I didn't want people to use direct_io without > understanding what it does (side effects and all) *on Mac OS X*.
I think I understand why... > > Ah, this is what I'm not entirely pleased with. I'd like for mmap to simply > > fail, rather than *almost* work. Then, applications that try to detect > > whether > > or not mmap is supported will be able to fall back on a reasonable > > substitute if > > mmap is unavailable. > > > > (This can lead to file corruption in cases where the application hasn't been > > coded very carefully, too.) > > Yes. You should file a bug with Apple--this is a generic issue, not > limited to MacFUSE. This pretty much kills write support for pytagsfs on OSX. I can't tell people to use pytagsfs but "just make sure your apps don't call mmap!". How unfortunate. For now, I'll have to make pytagsfs force read-only mounts on Darwin. Maybe I'll let people override that with --force-write-support or so (which would also print a stern warning that their files will likely become corrupted). Has a bug about this been filed with Apple yet? I'm not sure if I'm qualified to file it myself, as I don't know the kernel interface well enough to even express what the correct behavior would be (although I know what consequences I'd like as an FS developer). Apple isn't exactly known for being willing to take suggestions. Thanks, Forest -- Forest Bond http://www.alittletooquiet.net http://www.pytagsfs.org
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