Re: i_version changes

2008-02-15 Thread Jean noel Cordenner
Peter Staubach a écrit : Few month ago, I ran a FFSB test on a 2.6.23 kernel enabling or not the i_version flag. http://bullopensource.org/ext4/20071116/ffsb-write.html This is good information. A couple of questions -- what is the "-I 256" option used for the ext4 mkfs? This option force

Re: i_version changes

2008-02-14 Thread Peter Staubach
Jean noel Cordenner wrote: hi, Peter Staubach a écrit : Is the perceived performance hit really going to be as large as suspected? We already update the time fields fairly often and we don't pay a huge penalty for those, or at least not a penalty that we aren't willing to pay. Has anyone mea

Re: i_version changes

2008-02-14 Thread Peter Staubach
NeilBrown wrote: On Thu, February 14, 2008 8:32 am, Peter Staubach wrote: I don't think that this is quite true. If the file is changed when the NFS server is not running, then the value of i_version which is used when the NFS server starts up again must be different than the value which was

Re: i_version changes

2008-02-14 Thread Jean noel Cordenner
hi, Peter Staubach a écrit : Is the perceived performance hit really going to be as large as suspected? We already update the time fields fairly often and we don't pay a huge penalty for those, or at least not a penalty that we aren't willing to pay. Has anyone measured the cost? Few month

Re: i_version changes

2008-02-13 Thread NeilBrown
On Thu, February 14, 2008 8:32 am, Peter Staubach wrote: > > I don't think that this is quite true. If the file is changed > when the NFS server is not running, then the value of i_version > which is used when the NFS server starts up again must be > different than the value which was previously u

Re: i_version changes

2008-02-13 Thread J. Bruce Fields
On Thu, Feb 14, 2008 at 08:19:19AM +1100, NeilBrown wrote: > On Thu, February 14, 2008 7:26 am, J. Bruce Fields wrote: > > > It's not OK to update it only sometimes. If updates are made while nfsd > > isn't running, those needed to be reflected in the change attribute, so > > the changes aren't m

Re: i_version changes

2008-02-13 Thread Peter Staubach
NeilBrown wrote: On Thu, February 14, 2008 7:26 am, J. Bruce Fields wrote: It's not OK to update it only sometimes. If updates are made while nfsd isn't running, those needed to be reflected in the change attribute, so the changes aren't missed when nfsd comes back up. For NFSD's nee

Re: i_version changes

2008-02-13 Thread NeilBrown
On Thu, February 14, 2008 7:26 am, J. Bruce Fields wrote: > It's not OK to update it only sometimes. If updates are made while nfsd > isn't running, those needed to be reflected in the change attribute, so > the changes aren't missed when nfsd comes back up. For NFSD's needs, it is only necessar

Re: i_version changes

2008-02-13 Thread J. Bruce Fields
On Wed, Feb 13, 2008 at 01:52:14PM +0100, Christoph Hellwig wrote: > On Tue, Feb 12, 2008 at 03:06:25PM -0500, J. Bruce Fields wrote: > > > First there's a complete lack of documentation on this, which is very > > > bad. Please document what the new semantics for i_version on regular > > > files a

Re: i_version changes

2008-02-13 Thread Andreas Dilger
On Feb 13, 2008 09:07 -0500, Trond Myklebust wrote: > On Wed, 2008-02-13 at 13:52 +0100, Christoph Hellwig wrote: > > Btw, stupid question: the commit message for the i_version changes > > mentions this is to work around lack of granularity for ctime updates. > > But all mo

Re: i_version changes

2008-02-13 Thread Trond Myklebust
On Wed, 2008-02-13 at 13:52 +0100, Christoph Hellwig wrote: > Btw, stupid question: the commit message for the i_version changes > mentions this is to work around lack of granularity for ctime updates. > But all modern filesystems (and I includ ext4 in that here) have 64bit > timest

Re: i_version changes

2008-02-13 Thread Christoph Hellwig
r to > use ctime or i_version as the change attribute. Probably through export_operations somehow. Andreas mentioned in the other reply that he wants it only conditionally due to the overhead on extN, and enabling this from an export operation called when nfs exporting a filesystem. Btw, stupid

Re: i_version changes

2008-02-13 Thread Andreas Dilger
On Feb 12, 2008 15:06 -0500, J. Bruce Fields wrote: > On Sun, Feb 10, 2008 at 08:30:41AM +0100, Christoph Hellwig wrote: > > Third using the MS_ flag but then actually having a filesystem > > mount option to enable it is more than confusing. After all MS_ > > options (at least the exported parts)

Re: i_version changes

2008-02-12 Thread J. Bruce Fields
On Sun, Feb 10, 2008 at 08:30:41AM +0100, Christoph Hellwig wrote: > I think the i_version changes that hit mainline about a week ago are > not as nice as they should be. > > First there's a complete lack of documentation on this, which is very > bad. Please document what t

i_version changes

2008-02-09 Thread Christoph Hellwig
I think the i_version changes that hit mainline about a week ago are not as nice as they should be. First there's a complete lack of documentation on this, which is very bad. Please document what the new semantics for i_version on regular files are supposed to be, and how it differes fro