Re: PUFFS ADVLOCK is too greedy

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Emmanuel Dreyfus <manu%netbsd.org@localhost> wrote:

> Please consider the test case below, ran on a PUFFS/perfuse/glusterfs
> mount. A look at the PUFFS operation trace shows that the kernel sends
> ADVLOCK for f0, f1 and m when a lock is requested on m.

Here is where the extra ADVLOCK happen:
sys_exit -> exit1 -> fd_free -> fd_close -> VOP_ADVLOCK

In a nutshell, NetBSD clears locks on all file descriptor when a process
exit, that include read-only descriptors, and FUSE filesystems seem to
be unconfortable with that.

I am not sure of where this should be fixed: should we avoid unlocking
read-only files in fd_close()? That seems a good idea performance-wise.

Or is it a desirable behavior on native filesystems while being a bug
for FUSE filesystems?  In that case, it means I need to filter the
operation in perfused.

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost