Re: [PATCH] GOP_ALLOC and fallocate for PUFFS

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

Here is my latest patch:
http://ftp.espci.fr/shadow/manu/puffs-falloc.patch

The whole thing is not very satisfying. Here are a few issues:

- if we do not have fallocate and go the emulation way writing zeroes,
we must first call VOP_PUTPAGES for the whole vnode so that no data
remain in th cache while we try adding new blocks. This means that even
writing a single byte will cause the whole file to be flushed,
completely defeating write cache.

- I allocate file storage for any cached write, without actually cheking
if the written area are already mapped to allocated storage or not.  How
could I check that?

Generally speaking I start wondering if it is the kernel job to maitain
the PUFFS write cache.

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