Note that this waits on any range that overlaps both an outstanding
LAYOUTRETURN and a current layout. Whereas what you really want is to
wait on any range that overlaps an outstanding LAYOUTRETURN. One way
to get the desired behavior would be to have LAYOUTRETURN insert an
"invalid" lseg covering its range.
Fred
On Tue, Sep 14, 2010 at 3:53 AM, Benny Halevy <bhalevy@xxxxxxxxxxx> wrote:
> Introduce lo_rpcwaitq and sleep on it while there's an lseg marked invalid,
> i.e. it is being returned (in the future, it could also be layoutget in progress).
>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> ---
> fs/nfs/inode.c | 1 +
> fs/nfs/nfs4proc.c | 25 ++++++++++++++++++++++---
> fs/nfs/pnfs.c | 37 ++++++++++++++++++-------------------
> fs/nfs/pnfs.h | 3 +++
> include/linux/nfs_fs.h | 1 +
> 5 files changed, 45 insertions(+), 22 deletions(-)
>
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 7621cfc..059bdf7 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -1462,6 +1462,7 @@ static inline void nfs4_init_once(struct nfs_inode *nfsi)
> init_rwsem(&nfsi->rwsem);
> #ifdef CONFIG_NFS_V4_1
> init_waitqueue_head(&nfsi->lo_waitq);
> + rpc_init_wait_queue(&nfsi->lo_rpcwaitq, "pNFS Layout");
> nfsi->pnfs_layout_suspend = 0;
> nfsi->layout = NULL;
> #endif /* CONFIG_NFS_V4_1 */
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 48a763e..f12568d 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5442,13 +5442,32 @@ nfs4_layoutget_prepare(struct rpc_task *task, void *calldata)
> {
> struct nfs4_layoutget *lgp = calldata;
> struct inode *ino = lgp->args.inode;
> + struct nfs_inode *nfsi = NFS_I(ino);
> struct nfs_server *server = NFS_SERVER(ino);
> + struct pnfs_layout_segment *lseg;
>
> dprintk("--> %s\n", __func__);
> - if (nfs4_setup_sequence(server, NULL, &lgp->args.seq_args,
> - &lgp->res.seq_res, 0, task))
> + spin_lock(&ino->i_lock);
> + lseg = pnfs_has_layout(nfsi->layout, &lgp->args.range);
> + if (likely(!lseg)) {
> + spin_unlock(&ino->i_lock);
> + dprintk("%s: no lseg found, proceeding\n", __func__);
> + if (!nfs4_setup_sequence(server, NULL, &lgp->args.seq_args,
> + &lgp->res.seq_res, 0, task))
> + rpc_call_start(task);
> return;
> - rpc_call_start(task);
> + }
> + if (!lseg->valid) {
> + put_lseg_locked(lseg);
> + spin_unlock(&ino->i_lock);
> + dprintk("%s: invalid lseg found, waiting\n", __func__);
> + rpc_sleep_on(&nfsi->lo_rpcwaitq, task, NULL);
> + return;
> + }
> + *lgp->lsegpp = lseg;
> + spin_unlock(&ino->i_lock);
> + dprintk("%s: valid lseg found, no rpc required\n", __func__);
> + rpc_exit(task, NFS4_OK);
> }
>
> static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index bc4f0c1..2450383 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -430,7 +430,7 @@ destroy_lseg(struct kref *kref)
> PNFS_LD_IO_OPS(lseg->layout)->free_lseg(lseg);
> }
>
> -static void
> +void
> put_lseg_locked(struct pnfs_layout_segment *lseg)
> {
> bool do_wake_up;
> @@ -444,8 +444,10 @@ put_lseg_locked(struct pnfs_layout_segment *lseg)
> do_wake_up = !lseg->valid;
> nfsi = PNFS_NFS_INODE(lseg->layout);
> kref_put(&lseg->kref, destroy_lseg);
> - if (do_wake_up)
> + if (do_wake_up) {
> wake_up(&nfsi->lo_waitq);
> + rpc_wake_up(&nfsi->lo_rpcwaitq);
> + }
> }
>
> void
> @@ -999,7 +1001,7 @@ has_matching_lseg(struct pnfs_layout_segment *lseg,
> /*
> * lookup range in layout
> */
> -static struct pnfs_layout_segment *
> +struct pnfs_layout_segment *
> pnfs_has_layout(struct pnfs_layout_hdr *lo,
> struct pnfs_layout_range *range)
> {
> @@ -1057,22 +1059,20 @@ _pnfs_update_layout(struct inode *ino,
>
> /* Check to see if the layout for the given range already exists */
> lseg = pnfs_has_layout(lo, &arg);
> - if (lseg && !lseg->valid) {
> - put_lseg_locked(lseg);
> - /* someone is cleaning the layout */
> - lseg = NULL;
> - goto out_unlock;
> - }
> -
> if (lseg) {
> - dprintk("%s: Using cached lseg %p for %llu@%llu iomode %d)\n",
> - __func__,
> - lseg,
> - arg.length,
> - arg.offset,
> - arg.iomode);
> + if (lseg->valid) {
> + dprintk("%s: Using cached lseg %p for %llu@%llu "
> + "iomode %d)\n",
> + __func__,
> + lseg,
> + arg.length,
> + arg.offset,
> + arg.iomode);
>
> - goto out_unlock;
> + goto out_unlock;
> + }
> + /* someone is cleaning the layout */
> + put_lseg_locked(lseg);
> }
>
> /* if get layout already failed once goto out */
> @@ -1097,8 +1097,7 @@ out:
> nfsi->layout->state, lseg);
> return;
> out_unlock:
> - if (lsegpp)
> - *lsegpp = lseg;
> + *lsegpp = lseg;
> spin_unlock(&ino->i_lock);
> goto out;
> }
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index ea70385..f7f567e 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -34,6 +34,9 @@ extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool wait);
> /* pnfs.c */
> extern const nfs4_stateid zero_stateid;
>
> +void put_lseg_locked(struct pnfs_layout_segment *);
> +struct pnfs_layout_segment *pnfs_has_layout(struct pnfs_layout_hdr *,
> + struct pnfs_layout_range *);
> void _pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
> loff_t pos, u64 count, enum pnfs_iomode access_type,
> struct pnfs_layout_segment **lsegpp);
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index 5bafa95..196c0c6 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -213,6 +213,7 @@ struct nfs_inode {
> /* pNFS layout information */
> #if defined(CONFIG_NFS_V4_1)
> wait_queue_head_t lo_waitq;
> + struct rpc_wait_queue lo_rpcwaitq;
> struct pnfs_layout_hdr *layout;
> time_t pnfs_layout_suspend;
> #endif /* CONFIG_NFS_V4_1 */
> --
> 1.7.2.2
>
> --
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