Re: [PATCH, RFC] xip: use i_mutex for xip_file_fault

[Marco Stornelli]

Il 10/09/2011 17:56, Al Viro ha scritto:
> On Sat, Sep 10, 2011 at 05:31:39PM +0200, Marco Stornelli wrote:
> > From: Marco Stornelli<marco.stornelli@xxxxxxxxx>
> >
> > There aren't sufficient sync points for a fs for xip operations. In
> > particular for the mmap case. It can be not sufficient to lock/unlock
> > to do some operation inside get_xip_mem callback. For xip_file_read
> > it's really easy to write a fs specific wrapper, xip_file_write hold
> > i_mutex so no problem. With this patch we can avoid concurrent truncate
> > operation and xip mmap.
>
> Umm...  I really don't like that; what's going to happen if you have a file
> mmapped and do write() to that file from address in that mapping?

Nothing strange. There is a serialization of the operations. Maybe I 
don't understand the point here.

Marco
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