Re: [PATCH 1/1] fs/mpage.c: forgotten WRITE_SYNC in case of data integrity write

Jan Kara
2014-03-14T14:15:16Z

On Fri 14-03-14 10:11:43, Tejun Heo wrote:
> > Also, could you please help me do understand how can I guarantee
> > integrity in case of block device with big volatile
> > cache and filesystem, which does not support REQ_FLUSH/FUA?
>
> If a device has a volatile cache but doesn't support flush, it can't
> guarantee integrity. There's no way for its user to determine or
> force whether certain data is on non-volatile media. It's an
> inherently broken device.
I think his problem was that the device does support REQ_FLUSH/FUA but
the filesystem on top of it doesn't issue it properly. That's a filesystem
problem so fix the filesystem... :) Which one is it?

Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR