Re: [RFC] v9fs: readpage support

[Eric Van Hensbergen <ericvh@gmail.com>]

On 11/18/05, Christoph Hellwig <hch@infradead.org> wrote:
>
> > +     struct v9fs_fcall *fcall = NULL;
> > +     int fid = v9f->fid;
> > +     int total = 0;
> > +     int result = 0;
> > +
> > +     page_cache_get(page);
>
> ->readpage is synchronous, so you shouldn't need to grab a reference.
>

Weird things happen if I don't have page_cache_get - perhaps there's
something else I need to call if I don't call that?

bash-2.05b# /root/fsx/fsx -N 1000 -W -d testfile
mapped writes DISABLED
1 write 0x1f7e6 thru    0x2250e (0x2d29 bytes)
2 write 0x10f13 thru    0x16b11 (0x5bff bytes)
3 mapread       0x1f48a thru    0x2250e (0x3085 bytes)
Bad page state at free_hot_cold_page (in process 'fsx', page c0000000006175e0)
flags:0x0000700000000008 mapping:c0000000073606b0 mapcount:0 count:0
Backtrace:
Call Trace:
[C0000000072274B0] [C000000000025890] .show_stack+0x50/0x1cc (unreliable)
[C000000007227560] [C00000000007D0E4] .bad_page+0x90/0xec
[C0000000072275E0] [C00000000007DAA4] .free_hot_cold_page+0x80/0x1ac
[C000000007227680] [C00000000007DC1C] .__pagevec_free+0x4c/0x78
[C000000007227710] [C000000000088B3C] .release_pages+0x1fc/0x2c0
[C000000007227840] [C000000000088F64] .__pagevec_lru_add+0x138/0x170
[C0000000072278F0] [C000000000081C48] .__do_page_cache_readahead+0x27c/0x338
[C000000007227A50] [C00000000007981C] .filemap_nopage+0x308/0x460
[C000000007227B20] [C000000000091C30] .__handle_mm_fault+0x51c/0xe48
[C000000007227C20] [C0000000002BD5E8] .do_page_fault+0x524/0x7b4
[C000000007227E30] [C000000000004760] .handle_page_fault+0x20/0x54
Trying to fix it up, but a reboot is needed



I've incorporated the rest of your suggestions and found a bug in the
meanwhile.  I'll be submitting an amended patch to Andrew sometime
this week unless I hear back from you on the above issue.

Thanks for the comments Christoph.


          -eric