Re: [PATCH] Re: zero-filed page on VOP_PUTPAGES

[yamt%mwd.biglobe.ne.jp@localhost (YAMAMOTO Takashi)]

hi,

> YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost> wrote:
> 
>> alternatively, using puffs_msg_setcall, i think you can make GETATTR
>> reliably know if there's a pending SETATTR or not.
>> if there's a pending SETATTR, GETATTR can ignore a part of the reply
>> from the file server and returns the kernel's idea of the file attributes
>> instead.
> 
> That seems the best way, but you need to do it everywhere
> uvm_vnp_setsize() is called, that is:
> puffs_vnop_getattr
> dosetattr
> puffs_vnop_write

uvm_vnp_setsize merely changes the kernel's idea of the size of the file.
i think puffs_vnop_getattr already checks PNODE_METACACHE_* flags for cases
like this.

> 
> It seems useless in puffs_getvnode since no race can occur there,
> though.
> 
> We would have a PNODE_IN_RESIZE flag for struct pnode's pn_stat, set and
> cleared in dosetattr(), and use vp->v_size on uvm_vnp_setsize() calls
> when set? Or just avoid uvm_vnp_setsize() calls?

just avoid the calls.

YAMAMOTO Takashi

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