Re: [RFC PATCH 2/2] xfs_export_operations.commit_metadata

bpm
2010-02-10T20:14:51Z

Howdy,

On Wed, Feb 10, 2010 at 04:07:50AM -0500, Christoph Hellwig wrote:
> On Tue, Feb 09, 2010 at 06:33:37PM -0600, Ben Myers wrote:
> > hopefully
> > the XFS gurus can continue to provide guidance.
>
> Ccing the xfs list would help with that :)

I'll cross-post the next rev. ;)

> > + if (xfs_ipincount(c_xip)) {
> > + /*
> > + * AFAICS the child is always modified after the parent
> > + * in nfsd so should always have a larger lsn.
> > + */
> > + if (c_xip->i_itemp->ili_last_lsn > force_lsn) {
> > + force_lsn = c_xip->i_itemp->ili_last_lsn;
> > + } else {
> > + force_lsn = 0; /* whole thing */
> > + }
>
> I wouldn't rely on that and always take the larger one.

I am concerned that ili_last_lsn will roll over at some point. I
haven't figured out how to detect that yet.

> Now with the simplification of always having a non-zero first argument
> suggested in the previous mail this might be simplified down to:
>
> STATIC int
> xfs_fs_nfs_commit_metadata(
> struct dentry *parent,
> struct dentry *child)
> {
> struct xfs_inode *dp = XFS_I(parent->d_inode);
> struct xfs_inode *ip = NULL;
> struct xfs_mount *mp = dp->i_mount;
> xfs_lsn_t force_lsn = 0;
> int error = 0;
>
> if (child) {
> ip = XFS_I(child->d_inode);
> xfs_lock_two_inodes(dp, ip, XFS_ILOCK_SHARED);
> } else {
> xfs_ilock(dp, XFS_ILOCK_SHARED);
> }
>
> if (xfs_ipincount(dp))
> force_lsn = dp->i_itemp->ili_last_lsn;
> if (ip && xfs_ipincount(ip))
> force_lsn = max(force_lsn, ip->i_itemp->ili_last_lsn);
>
+ if (force_lsn)
> error = _xfs_log_force_lsn(mp, force_lsn, NULL);
>
> if (ip)
> xfs_iunlock(ip, XFS_ILOCK_SHARED);
> xfs_iunlock(dp, XFS_ILOCK_SHARED);
>
> return error;
> }

That's nice!

> Note that _xfs_log_force_lsn is new in the XFS tree, mainline still
> has _xfs_log_force with an lsn argument.

I've been working with Bruce's tree. Not sure how best to handle that.

Thanks,
Ben