Re: [PATCH] PUFFS with cache TTL from filesystem

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

YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost> wrote:

> - i feel that the api is too specific to the use of libperfuse.
>       - it should not require puffs_node.

I started without puffs_node at once but that require changing vnop
methods prototypes and makes them heavyweight. The chosen solution has
merits for the sake of readability and backward compatibility.


>       - i think you mixed up at least two separate features.
>         they ought to have separate flags.
>               - DIROP's ability to return file attribute
>               - attribute TTLs
> - it would be better to allow file server choose if it returns attributes
>   on DIROPs per-request basis rather than per-mount.  like nfsv3.

Those two are the same problem. 

We could simply ignore attributes when attribute TTL is set to 0. It
makes sense since on lookup/create/mkdir/mknod/symlink, the attributes
returned by the fileystem have no immediate use by the kernel. A TTL set
to 0 means they should not be used for a subsequent getattr, so we can
cut corners and just not save them.

And if the filesystem wants to set attributes without a TTL, there is
always the solution to set a far away TTL. Perahps I could just define a
magic value for that.

> - as new functions returns a pointer, it's better to follow
>   the existing naming convention.  ie. "p" of puffs_pn_getvap

Right.

> - please handle ticks wraparounds.

Any example of some code where this is done?

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