Re: [EXT4 set 4][PATCH 1/5] i_version:64 bit inode version

[Mingming Cao <cmm@us.ibm.com>]

On Tue, 2007-07-10 at 22:17 -0700, Andrew Morton wrote:
> On Tue, 10 Jul 2007 22:09:08 -0400 Mingming Cao <cmm@us.ibm.com> wrote:
> 
> > David Chinneer pointed that we need to journal the version number
> > updates together with the operations that causes the change of the inode
> > version number, in order to survive server crashes so clients won't see
> > the counter go backwards.
> > 
> > So increment i_version in fs code is probably the place to ensure the
> > inode version changes are stored to disk. It's seems update the ext4
> > inode version in every ext4_mark_inode_dirty() is the easiest way.
> 
> That still makes us dependent upon _something_ changing the inode.  For
> overwrites the only something is mtime.
> 
> If we don't want to have a peculiar dependency upon s_time_gran=1e9 (and
> I don't think we do) then I guess we'll need new code in or around
> file_update_time() to do this.

do you mean mark inode dirty all the times in file_update_time()? Not
sure about the overhead for ext3/4.

Mingming