file change notification issues
Hasch at t-online.de
Sat Feb 1 18:09:26 GMT 2003
jra at dp.samba.org wrote:
>Great detective work ! Actaully this is a bug in IIS. The
>protocol states that STATUS_NOTIFY_ENUM_DIR is a valid return,
>if too many files were changed (hmmm. define "too many" :-).
>It would be possible to cause this to break on Windows 2000
>servers also, but I imagine that under 'normal' circumstances
>few enough files have changed that this doesn't cause a problem
well it looks like Matlab, the application I'm having trouble with, also
doesn't like STATUS_NOTIFY_ENUM_DIR
as return value. It starts polling its working directory like crazy,
which is quite annyoing (you can change the program
configuration, but this is the default for me). Older versions of Matlab
behave better, I checked this some time ago.
I hacked a patch to have Samba behave like W2K and deliver the name of
the changed file and it looks quite good.
No more endless file stat polling, so I'm all for adding this
functionality to Samba :-)
The most difficult part is getting a file name from Linux without
reimplementing the change notification interface.
I don't like fam or dazuko or the other stuff that is available as an
alternative to the kernel dnotify support,
it's too much bloat.
For now I simply added a fcntl to the Linux kernel to return the desired
file name. This requires only minor changes
in Samba and Linux, however it has most likely races in it and will
probably only work for my most simple case...
Btw. my original problem from my posts last week was different. It seems
like the behaviour I was describing only
happens when running Samba in a VMware session. Testing on several real
machines doesn't show the problem.
Odd... I can still send you traces, but I think it's not that interesting.
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