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 16:30 -0700, Andrew Morton wrote:
> On Sun, 01 Jul 2007 03:37:04 -0400
> Mingming Cao <cmm@us.ibm.com> wrote:
> 
> > This patch converts the 32-bit i_version in the generic inode to a 64-bit
> > i_version field.
> > 
> 
> That's obvious from the patch.  But what was the reason for making this
> (unrelated to ext4) change?
> 

The need is came from NFSv4

On Fri, 2007-05-25 at 18:25 +0200, Jean noel Cordenner wrote: 
> Hi,
> 
> This is an update of the i_version patch.
> The i_version field is a 64bit counter that is set on every inode
> creation and that is incremented every time the inode data is modified
> (similarly to the "ctime" time-stamp).
> The aim is to fulfill a NFSv4 requirement for rfc3530:
> "5.5.  Mandatory Attributes - Definitions
> Name		#	DataType   Access   Description
> ___________________________________________________________________
> change		3	uint64       READ     A value created by the
> 		server that the client can use to determine if file
> 		data, directory contents or attributes of the object
> 		have been modified.  The servermay return the object's
> 		time_metadata attribute for this attribute's value but
> 		only if the filesystem object can not be updated more
> 		frequently than the resolution of time_metadata.
> "
> 

> Please update the changelog for this.
> 

Is above description clear to you?


> > Index: linux-2.6.21/include/linux/fs.h
> > ===================================================================
> > --- linux-2.6.21.orig/include/linux/fs.h
> > +++ linux-2.6.21/include/linux/fs.h
> > @@ -549,7 +549,7 @@ struct inode {
> >  	uid_t			i_uid;
> >  	gid_t			i_gid;
> >  	dev_t			i_rdev;
> > -	unsigned long		i_version;
> > +	u64			i_version;
> >  	loff_t			i_size;
> >  #ifdef __NEED_I_SIZE_ORDERED
> >  	seqcount_t		i_size_seqcount;
> 

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