Re: OT? 10.4 VFS - ls works, but Carbon File Mgr listing does not
Re: OT? 10.4 VFS - ls works, but Carbon File Mgr listing does not
- Subject: Re: OT? 10.4 VFS - ls works, but Carbon File Mgr listing does not
- From: Quinn <email@hidden>
- Date: Fri, 29 Jul 2005 12:15:05 +0100
At 15:12 -0500 28/7/05, Brian Bergstrand wrote:
This may be OT, and if so let me know, but there are no lists for
Carbon File Mgr / VFS interaction.
Certainly not off topic. VFS/File Manager interactions are
bread'n'butter questions for me (-:
Last month I posted a quick summary of my standard advice about this
sort of problem.
At 10:43 +0100 29/6/05, Quinn wrote:
Debugging this sort of problem is hard. My experience is they are
related to how the File Manager uses the BSD file system APIs. The
File Manager stresses these APIs to the max, and some slight slip up
in your VFS's support can cause very hard-to-debug problems. Those
cases that I've found, I've documented in Q&As on our web site.
However, I'm sure there are still many others yet to be found.
<http://developer.apple.com/technicalqas/Darwin/idxFileManagement-date.html>
<http://developer.apple.com/technicalqas/Darwin/idxKernel-date.html>
You might also want to look at the File Manager section of Technote
2124 "Mac OS X Debugging Magic", which has some useful tips.
<http://developer.apple.com/technotes/tn2004/tn2124.html#SECCSFM>
Specifically, if you can find a way to enable the _debug libraries,
you'll get useful File Manager info from fs_usage.
If ATS is wedged, not much on the system is going to work. What
does a "sample" log of ATS look like?
Have you tested your mmap code path? This is something that VFS
developers often get wrong, and the system uses mmap a lot.
* * *
The best way to get to the bottom of problems like this is to open a
DTS incident. That will allow me to provide you with full time
help. If that's not possible, I can continue to help out on this
list, but supporting mailing lists isn't my primary focus.
<http://developer.apple.com/technicalsupport/index.html>
Notwithstanding the above, I'm happy to make wild guesses on this list (-:
From your email it seems that, sometimes, the items show up and then
disappear. My guess is that this is happening all the time, except
that most of the time it happens so quickly that the Finder doesn't
get to render the icons.
The most common reason for items appearing and then disappearing in
the Finder is that the items are returned from directory iteration
APIs (at the BSD level, these readdir and getdirentriesattr) and then
Finder tries to probe them for information and that probe fails with
some sort of error.
The best way to debug this sort of problem is to run fs_usage against
the Finder as you mount the volume. fs_usage will show you any
errors being returned. You can then check to see if they're expected.
If the situation is too confused at mount time, you might be able to
get Finder to open a window (which will be blank, of course) using Go
to Folder (or the "open" command line tool).
Finally, you can try doing this with _debug libraries enabled.
That's tricky to achieve with Finder. I managed to do it, but I
can't remember exactly how. It had something to do with force quit
(-:
S+E
--
Quinn "The Eskimo!" <http://www.apple.com/developer/>
Apple Developer Technical Support * Networking, Communications, Hardware
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