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Re: [PATCH] XFS: remove i_gen from incore inode

To: xfs@xxxxxxxxxxx
Subject: Re: [PATCH] XFS: remove i_gen from incore inode
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Fri, 31 Oct 2008 12:27:58 +1100
In-reply-to: <20081022062044.GJ18495@disturbed>
Mail-followup-to: xfs@xxxxxxxxxxx
References: <1223417549-9920-1-git-send-email-david@xxxxxxxxxxxxx> <20081022062044.GJ18495@disturbed>
User-agent: Mutt/1.5.18 (2008-05-17)
Ping?

On Wed, Oct 22, 2008 at 05:20:44PM +1100, Dave Chinner wrote:
> Ping?
> 
> On Wed, Oct 08, 2008 at 09:12:29AM +1100, Dave Chinner wrote:
> > i_gen is incremented in directory operations when the
> > directory is changed. It is never read or otherwise used
> > so it should be removed to help reduce the size of the
> > struct xfs_inode.
> > 
> > The patch also removes a duplicate logging of the directory
> > inode core. We only need to do this once per transaction
> > so kill the one associated with the i_gen increment.
> > 
> > Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
> > ---
> >  fs/xfs/xfs_inode.h    |    1 -
> >  fs/xfs/xfs_rename.c   |   12 ++----------
> >  fs/xfs/xfs_vnodeops.c |   29 ++---------------------------
> >  3 files changed, 4 insertions(+), 38 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> > index a8f1e68..5784f8e 100644
> > --- a/fs/xfs/xfs_inode.h
> > +++ b/fs/xfs/xfs_inode.h
> > @@ -272,7 +272,6 @@ typedef struct xfs_inode {
> >     unsigned short          i_flags;        /* see defined flags below */
> >     unsigned char           i_update_core;  /* timestamps/size is dirty */
> >     unsigned char           i_update_size;  /* di_size field is dirty */
> > -   unsigned int            i_gen;          /* generation count */
> >     unsigned int            i_delayed_blks; /* count of delay alloc blks */
> >  
> >     xfs_icdinode_t          i_d;            /* most of ondisk inode */
> > diff --git a/fs/xfs/xfs_rename.c b/fs/xfs/xfs_rename.c
> > index d700dac..02f0e8f 100644
> > --- a/fs/xfs/xfs_rename.c
> > +++ b/fs/xfs/xfs_rename.c
> > @@ -367,19 +367,11 @@ xfs_rename(
> >                                     &first_block, &free_list, spaceres);
> >     if (error)
> >             goto abort_return;
> > -   xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> >  
> > -   /*
> > -    * Update the generation counts on all the directory inodes
> > -    * that we're modifying.
> > -    */
> > -   src_dp->i_gen++;
> > +   xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> >     xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
> > -
> > -   if (new_parent) {
> > -           target_dp->i_gen++;
> > +   if (new_parent)
> >             xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
> > -   }
> >  
> >     /*
> >      * If this is a synchronous mount, make sure that the
> > diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
> > index 8b6812f..7a72b0a 100644
> > --- a/fs/xfs/xfs_vnodeops.c
> > +++ b/fs/xfs/xfs_vnodeops.c
> > @@ -1625,8 +1625,6 @@ xfs_create(
> >             xfs_trans_set_sync(tp);
> >     }
> >  
> > -   dp->i_gen++;
> > -
> >     /*
> >      * Attach the dquot(s) to the inodes and modify them incore.
> >      * These ids of the inode couldn't have changed since the new
> > @@ -1993,13 +1991,6 @@ xfs_remove(
> >     }
> >     xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> >  
> > -   /*
> > -    * Bump the in memory generation count on the parent
> > -    * directory so that other can know that it has changed.
> > -    */
> > -   dp->i_gen++;
> > -   xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
> > -
> >     if (is_dir) {
> >             /*
> >              * Drop the link from ip's "..".
> > @@ -2017,8 +2008,8 @@ xfs_remove(
> >     } else {
> >             /*
> >              * When removing a non-directory we need to log the parent
> > -            * inode here for the i_gen update.  For a directory this is
> > -            * done implicitly by the xfs_droplink call for the ".." entry.
> > +            * inode here.  For a directory this is done implicitly
> > +            * by the xfs_droplink call for the ".." entry.
> >              */
> >             xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
> >     }
> > @@ -2178,7 +2169,6 @@ xfs_link(
> >     if (error)
> >             goto abort_return;
> >     xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> > -   tdp->i_gen++;
> >     xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
> >  
> >     error = xfs_bumplink(tp, sip);
> > @@ -2355,18 +2345,10 @@ xfs_mkdir(
> >     }
> >     xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
> >  
> > -   /*
> > -    * Bump the in memory version number of the parent directory
> > -    * so that other processes accessing it will recognize that
> > -    * the directory has changed.
> > -    */
> > -   dp->i_gen++;
> > -
> >     error = xfs_dir_init(tp, cdp, dp);
> >     if (error)
> >             goto error2;
> >  
> > -   cdp->i_gen = 1;
> >     error = xfs_bumplink(tp, dp);
> >     if (error)
> >             goto error2;
> > @@ -2653,13 +2635,6 @@ xfs_symlink(
> >     xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
> >  
> >     /*
> > -    * Bump the in memory version number of the parent directory
> > -    * so that other processes accessing it will recognize that
> > -    * the directory has changed.
> > -    */
> > -   dp->i_gen++;
> > -
> > -   /*
> >      * If this is a synchronous mount, make sure that the
> >      * symlink transaction goes to disk before returning to
> >      * the user.
> > -- 
> > 1.5.6.5
> > 
> > 
> > 
> 
> -- 
> Dave Chinner
> david@xxxxxxxxxxxxx
> 
> 
> 

-- 
Dave Chinner
david@xxxxxxxxxxxxx

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