Re: [PATCH 1/1] nfs4.1: fix several problems with _pnfs_return_layout

[Benny Halevy <benny@tonian.com>]

On 2011-06-13 18:54, Fred Isaman wrote:
> _pnfs_return_layout had the following problems:
> 
> - it did not call pnfs_free_lseg_list on all paths
> - it unintentionally did a forgetful return when there was no outstanding io
> - it raced with concurrent LAYOUTGETS
> 
> Signed-off-by: Fred Isaman <iisaman@netapp.com>

ACK

Benny

> ---
>  fs/nfs/nfs4proc.c |    8 ++++----
>  fs/nfs/pnfs.c     |    8 +++++---
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index bc78597..2b2f51b 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5757,6 +5757,7 @@ static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
>  {
>  	struct nfs4_layoutreturn *lrp = calldata;
>  	struct nfs_server *server;
> +	struct pnfs_layout_hdr *lo = NFS_I(lrp->args.inode)->layout;
>  
>  	dprintk("--> %s\n", __func__);
>  
> @@ -5768,16 +5769,15 @@ static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
>  		nfs_restart_rpc(task, lrp->clp);
>  		return;
>  	}
> +	spin_lock(&lo->plh_inode->i_lock);
>  	if (task->tk_status == 0) {
> -		struct pnfs_layout_hdr *lo = NFS_I(lrp->args.inode)->layout;
> -
>  		if (lrp->res.lrs_present) {
> -			spin_lock(&lo->plh_inode->i_lock);
>  			pnfs_set_layout_stateid(lo, &lrp->res.stateid, true);
> -			spin_unlock(&lo->plh_inode->i_lock);
>  		} else
>  			BUG_ON(!list_empty(&lo->plh_segs));
>  	}
> +	lo->plh_block_lgets--;
> +	spin_unlock(&lo->plh_inode->i_lock);
>  	dprintk("<-- %s\n", __func__);
>  }
>  
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 8ff8c1b..1abb300 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -640,12 +640,14 @@ _pnfs_return_layout(struct inode *ino)
>  
>  	spin_lock(&ino->i_lock);
>  	lo = nfsi->layout;
> -	if (!lo || !mark_matching_lsegs_invalid(lo, &tmp_list, NULL)) {
> +	if (!lo) {
>  		spin_unlock(&ino->i_lock);
> -		dprintk("%s: no layout segments to return\n", __func__);
> -		goto out;
> +		dprintk("%s: no layout to return\n", __func__);
> +		return status;
>  	}
>  	stateid = nfsi->layout->plh_stateid;
> +	mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
> +	lo->plh_block_lgets++;
>  	/* Reference matched in nfs4_layoutreturn_release */
>  	get_layout_hdr(lo);
>  	spin_unlock(&ino->i_lock);

-- 
Benny Halevy
CTO, Tonian Inc.

Tel: +972-54-802-8340
benny@tonian.com