Re: [Dazuko-devel] Patch 6/7

[John Ogness]

On 2010-08-06, Lino Sanfilippo <address@hidden> wrote:
> This fixes a bug that has been discovered by Julien Bourgeois:
>
> If a file within dazukofs is mmaped and the content is read and
> afterwards the file is modified via write(), the content shown via
> mmap() is still the same as it was before the write() call.  In
> other words, the content modification done by write() is not visible
> for readers that use mmap.
>
> The reason is, that with mmap() memory pages are created for the
> _upper_ file, whereas write() and read() only access pages that
> belong to the lower file.  When a lower page is modified after its
> corresponding upper page has been created, the upper page is not
> updated and thus both pages are out of sync.
>
> This patch ensures that the upper pages that correspond to the file
> content that is modified via write() are marked dirty, so that a
> subsequent read from it causes the content to be refreshed from
> disk.

Thank you. The patch has been included in 3.1.4-rc1.

John Ogness

-- 
Dazuko Maintainer