Does anyone know how to set up mmap on FUSE (linux user-land file system)?
Or is it even possible to have mmap on FUSE?
Our file system checker can potentially check a lot more things if we can
have mmap working on a FUSE file system. Your help on this are well
appreciated!
-Junfeng
Forget to mention, we are checking linux 2.6. It appears to us that mmap
doesnt' work for FUSE in linux 2.6.
-Junfeng
On Sat, 12 Mar 2005, Junfeng Yang wrote:
>
> Does anyone know how to set up mmap on FUSE (linux user-land file system)?
> Or is it even possible to have mmap on FUSE?
>
> Our file system checker can potentially check a lot more things if we can
> have mmap working on a FUSE file system. Your help on this are well
> appreciated!
>
> -Junfeng
>
>
> _______________________________________________
> MC mailing list
> [email protected]
> http://keeda.stanford.edu/cgi-bin/mailman/listinfo/mc
>
On Mar 13, 2005, at 02:28, Junfeng Yang wrote:
> Forget to mention, we are checking linux 2.6. It appears to us that
> mmap
> doesnt' work for FUSE in linux 2.6.
IIRC, the reason mmap doesn't work on FUSE is because when it dirties
pages they
cannot be flushed reliably, because writing them out involves calling a
userspace
process which may allocate RAM, etc.
Cheers,
Kyle Moffett
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> > Forget to mention, we are checking linux 2.6. It appears to us
> > that mmap doesnt' work for FUSE in linux 2.6.
>
> IIRC, the reason mmap doesn't work on FUSE is because when it
> dirties pages they cannot be flushed reliably, because writing them
> out involves calling a userspace process which may allocate RAM,
> etc.
Yes. To be precise this only affects writable shared mmap(), which is
not used by the great majority of applications. Any other kind of
memory mapping should work OK.
Thanks,
Miklos