internel implemention of file operation

[Rajat Sharma]

> in this vm_operations_struct , there are open/close functions ,  are
there necessary  relations between file operations and this struct ?
well not really for open/close of vm_ops are of interest to filesystems,
but page fault handler and making page writable is where filesystem come
into picture. Have a look at ext4_file_vm_ops, it implements operations of
interest.

static const struct vm_operations_struct ext4_file_vm_ops = {
        .fault          = filemap_fault,
        .page_mkwrite   = ext4_page_mkwrite,
}

Note that only filesystem knows how to fill up this page.


On Thu, Jan 3, 2013 at 3:39 PM, horseriver <horserivers at gmail.com> wrote:

> On Thu, Jan 03, 2013 at 01:16:06PM +0530, Rajat Sharma wrote:
>
> > > will it be maped with vm_area struct ?
> > Yes if it is accessed via mmap system call.
>
> you know that , in the struct vm_area_struct,there is a struct
> vm_operations_struct * vm_ops;
>
> in this vm_operations_struct , there are open/close functions ,  are there
> necessary  relations between file
>
> operations and this struct ?
>
> thanks!
>
> >
> > > what is the relation between page-cache and file operation?
> > file operations for data access like read/write will look into page-cache
> > first before going to disk.
> >
> > -Rajat
> >
>
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