Re: [PATCH 1/1] SQUASHME pnfs-submit: replace layoutcommit_ctx with rpc_cred

[Boaz Harrosh <bharrosh@panasas.com>]

On 05/24/2010 09:28 PM, andros@netapp.com wrote:
> From: Andy Adamson <andros@netapp.com>
> 
> Taking a reference on the nfs_open_context to signal that a layoutcommit is
> needed is problematic because the last reference to the context triggers a
> close (nfs_release).  But, if the layout holds a reference on the
> nfs_open_context, then close will not be triggered.
> 
> Since we only use the rpc credential from the layoutcommit_ctx, replace the
> layoutcommit_ctx with the rpc_cred.
> 
> Hold a reference on the rpc_cred until the layoutcommit rpc returns.
> 
> If the layoutdriver fails to setup the layoutcommit, clear the layoutcommit
> properties and put the credential.
> 
> Signed-off-by: Andy Adamson <andros@netapp.com>

OK with this one I'm able to pass basic tests (git clone linux)

Missing is Tao's patch tho write.c::nfs_wb_all()

I've updated his patch ontop of this one and posting it (as separate email)

Thanks
Boaz

> ---
>  fs/nfs/inode.c            |    4 ++--
>  fs/nfs/nfs4state.c        |    2 +-
>  fs/nfs/pnfs.c             |   42 +++++++++++++++++-------------------------
>  fs/nfs/write.c            |    2 +-
>  include/linux/nfs4_pnfs.h |    6 ++++++
>  include/linux/nfs_fs.h    |    3 +--
>  include/linux/pnfs_xdr.h  |    1 -
>  7 files changed, 28 insertions(+), 32 deletions(-)
> 
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 7fd33d9..2b8e8e6 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -1110,7 +1110,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
>  	/*
>  	 * file needs layout commit, server attributes may be stale
>  	 */
> -	if (nfsi->layoutcommit_ctx && nfsi->change_attr >= fattr->change_attr) {
> +	if (do_layoutcommit(nfsi) && nfsi->change_attr >= fattr->change_attr) {
>  		dprintk("NFS: %s: layoutcommit is needed for file %s/%ld\n",
>  			__func__, inode->i_sb->s_id, inode->i_ino);
>  		return 0;
> @@ -1331,7 +1331,7 @@ static void pnfs_alloc_init_inode(struct nfs_inode *nfsi)
>  	nfsi->pnfs_layout_state = 0;
>  	memset(&nfsi->layout.stateid, 0, NFS4_STATEID_SIZE);
>  	nfsi->layout.roc_iomode = 0;
> -	nfsi->layoutcommit_ctx = NULL;
> +	nfsi->lo_cred = NULL;
>  	nfsi->pnfs_write_begin_pos = 0;
>  	nfsi->pnfs_write_end_pos = 0;
>  #endif /* CONFIG_NFS_V4_1 */
> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> index d145de1..bf03fde 100644
> --- a/fs/nfs/nfs4state.c
> +++ b/fs/nfs/nfs4state.c
> @@ -589,7 +589,7 @@ static void __nfs4_close(struct path *path, struct nfs4_state *state, fmode_t fm
>  #ifdef CONFIG_NFS_V4_1
>  		struct nfs_inode *nfsi = NFS_I(state->inode);
>  
> -		if (nfsi->layoutcommit_ctx)
> +		if (do_layoutcommit(nfsi))
>  			pnfs_layoutcommit_inode(state->inode, wait);
>  		if (has_layout(nfsi) && nfsi->layout.roc_iomode) {
>  			struct nfs4_pnfs_layout_segment range;
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 20285bc..ee530c8 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -145,21 +145,19 @@ find_pnfs(u32 id, struct pnfs_module **module) {
>  	return 0;
>  }
>  
> -/* Set context to indicate we require a layoutcommit
> +/* Set lo_cred to indicate we require a layoutcommit
>   * If we don't even have a layout, we don't need to commit it.
>   */
>  void
>  pnfs_need_layoutcommit(struct nfs_inode *nfsi, struct nfs_open_context *ctx)
>  {
> -	dprintk("%s: has_layout=%d layoutcommit_ctx=%p ctx=%p\n", __func__,
> -		has_layout(nfsi), nfsi->layoutcommit_ctx, ctx);
> +	dprintk("%s: has_layout=%d ctx=%p\n", __func__, has_layout(nfsi), ctx);
>  	spin_lock(&nfsi->lo_lock);
> -	if (has_layout(nfsi) && !nfsi->layoutcommit_ctx) {
> -		nfsi->layoutcommit_ctx = get_nfs_open_context(ctx);
> +	if (has_layout(nfsi) && !do_layoutcommit(nfsi)) {
> +		nfsi->lo_cred = get_rpccred(ctx->state->owner->so_cred);
>  		nfsi->change_attr++;
>  		spin_unlock(&nfsi->lo_lock);
> -		dprintk("%s: Set layoutcommit_ctx=%p\n", __func__,
> -			nfsi->layoutcommit_ctx);
> +		dprintk("%s: Set layoutcommit\n", __func__);
>  		return;
>  	}
>  	spin_unlock(&nfsi->lo_lock);
> @@ -755,7 +753,7 @@ _pnfs_return_layout(struct inode *ino, struct nfs4_pnfs_layout_segment *range,
>  				!pnfs_return_layout_barrier(nfsi, &arg));
>  		}
>  
> -		if (nfsi->layoutcommit_ctx) {
> +		if (do_layoutcommit(nfsi)) {
>  			status = pnfs_layoutcommit_inode(ino, wait);
>  			if (status) {
>  				dprintk("%s: layoutcommit failed, status=%d. "
> @@ -1910,16 +1908,9 @@ pnfs_layoutcommit_done(struct pnfs_layoutcommit_data *data)
>  
>  	dprintk("%s: (status %d)\n", __func__, data->status);
>  
> -	/* TODO: For now, set an error in the open context (just like
> -	 * if a commit failed) We may want to do more, much more, like
> -	 * replay all writes through the NFSv4
> -	 * server, or something.
> -	 */
> -	if (data->status < 0) {
> +	if (data->status < 0)
>  		printk(KERN_ERR "%s, Layoutcommit Failed! = %d\n",
>  		       __func__, data->status);
> -		data->ctx->error = data->status;
> -	}
>  
>  	/* TODO: Maybe we should avoid this by allowing the layout driver
>  	 * to directly xdr its layout on the wire.
> @@ -1929,9 +1920,7 @@ pnfs_layoutcommit_done(struct pnfs_layoutcommit_data *data)
>  							&nfsi->layout,
>  							&data->args,
>  							data->status);
> -
> -	/* release the open_context acquired in pnfs_writeback_done */
> -	put_nfs_open_context(data->ctx);
> +	put_rpccred(data->cred);
>  }
>  
>  /*
> @@ -1995,24 +1984,27 @@ pnfs_layoutcommit_inode(struct inode *inode, int sync)
>  		return -ENOMEM;
>  
>  	spin_lock(&nfsi->lo_lock);
> -	if (!nfsi->layoutcommit_ctx)
> +	if (!do_layoutcommit(nfsi))
>  		goto out_unlock;
>  
>  	data->args.inode = inode;
> -	data->cred  = nfsi->layoutcommit_ctx->cred;
> -	data->ctx = nfsi->layoutcommit_ctx;
> +	data->cred = nfsi->lo_cred;
>  
>  	/* Set up layout commit args*/
>  	status = pnfs_layoutcommit_setup(data, sync);
> -	if (status)
> -		goto out_unlock;
>  
>  	/* Clear layoutcommit properties in the inode so
>  	 * new lc info can be generated
>  	 */
>  	nfsi->pnfs_write_begin_pos = 0;
>  	nfsi->pnfs_write_end_pos = 0;
> -	nfsi->layoutcommit_ctx = NULL;
> +	nfsi->lo_cred = NULL;
> +
> +	if (status) {
> +		/* The layout driver failed to setup the layoutcommit */
> +		put_rpccred(data->cred);
> +		goto out_unlock;
> +	}
>  
>  	/* release lock on pnfs layoutcommit attrs */
>  	spin_unlock(&nfsi->lo_lock);
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index a4c95a0..2c1918e 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -1490,7 +1490,7 @@ static int nfs_commit_inode(struct inode *inode, int how)
>  					nfs_wait_bit_killable,
>  					TASK_KILLABLE);
>  #ifdef CONFIG_NFS_V4_1
> -		if (may_wait && NFS_I(inode)->layoutcommit_ctx) {
> +		if (may_wait && do_layoutcommit(NFS_I(inode))) {
>  			error = pnfs_layoutcommit_inode(inode, 1);
>  			if (error < 0)
>  				return error;
> diff --git a/include/linux/nfs4_pnfs.h b/include/linux/nfs4_pnfs.h
> index 4d47b48..c9ef43e 100644
> --- a/include/linux/nfs4_pnfs.h
> +++ b/include/linux/nfs4_pnfs.h
> @@ -80,6 +80,12 @@ has_layout(struct nfs_inode *nfsi)
>  	return nfsi->layout.ld_data != NULL;
>  }
>  
> +static inline bool
> +do_layoutcommit(struct nfs_inode *nfsi)
> +{
> +	return nfsi->lo_cred != NULL;
> +}
> +
>  #endif /* CONFIG_NFS_V4_1 */
>  
>  struct pnfs_layout_segment {
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index 98a8dc0..478b00c 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -203,11 +203,10 @@ struct nfs_inode {
>  #define NFS_INO_RW_LAYOUT_FAILED 1 	/* get rw layout failed stop trying */
>  #define NFS_INO_LAYOUT_ALLOC     2	/* bit lock for layout allocation */
>  	time_t pnfs_layout_suspend;
> +	struct rpc_cred		*lo_cred; /* layoutcommit credential */
>  	wait_queue_head_t lo_waitq;
>  	spinlock_t lo_lock;
>  	struct pnfs_layout_type layout;
> -	/* use rpc_creds in this open_context to send LAYOUTCOMMIT to MDS */
> -	struct nfs_open_context *layoutcommit_ctx;
>  	/* DH: These vars keep track of the maximum write range
>  	 * so the values can be used for layoutcommit.
>  	 */
> diff --git a/include/linux/pnfs_xdr.h b/include/linux/pnfs_xdr.h
> index a0bf341..154b04e 100644
> --- a/include/linux/pnfs_xdr.h
> +++ b/include/linux/pnfs_xdr.h
> @@ -86,7 +86,6 @@ struct pnfs_layoutcommit_data {
>  	bool is_sync;
>  	struct rpc_cred *cred;
>  	struct nfs_fattr fattr;
> -	struct nfs_open_context *ctx;
>  	struct pnfs_layoutcommit_arg args;
>  	struct pnfs_layoutcommit_res res;
>  	int status;