Re: [PATCH 01/50] pnfs: Prepare for flexfiles by pulling out common code

[Tom Haynes <thomas.haynes@primarydata.com>]

On Tue, Dec 16, 2014 at 12:32:30PM -0800, Tom Haynes wrote:
> On Tue, Dec 16, 2014 at 02:56:05PM -0500, Anna Schumaker wrote:
> > On 12/16/2014 02:01 PM, Tom Haynes wrote:
> > > The flexfilelayout driver will share some common code
> > > with the filelayout driver. This set of changes refactors
> > > that common code out to avoid any module depenencies.
> > 
> > Is this code generic enough that it could be used by the object and block layouts as well?  If not, maybe it the code could be moved to a filelayout_common module instead?
> 

Sorry about the earlier reply, Apple Mail.app was doing html spam.

The code is generic enough, but I don't see those other
layout types changing.

Do we want another module?

Note: The earlier patch set I had on this had the code
in the File Layout module, but Jeff objected to the
dependency.

 
> > 
> > Anna
> > 
> > > 
> > > Signed-off-by: Tom Haynes <loghyr@primarydata.com>
> > > ---
> > >  fs/nfs/Makefile                   |   2 +-
> > >  fs/nfs/filelayout/filelayout.c    | 291 ++------------------------------------
> > >  fs/nfs/filelayout/filelayout.h    |  11 --
> > >  fs/nfs/filelayout/filelayoutdev.c |   2 +-
> > >  fs/nfs/pnfs.h                     |  23 +++
> > >  fs/nfs/pnfs_nfsio.c               | 291 ++++++++++++++++++++++++++++++++++++++
> > >  6 files changed, 330 insertions(+), 290 deletions(-)
> > >  create mode 100644 fs/nfs/pnfs_nfsio.c
> > > 
> > > diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
> > > index 04cb830..7973c4e3 100644
> > > --- a/fs/nfs/Makefile
> > > +++ b/fs/nfs/Makefile
> > > @@ -27,7 +27,7 @@ nfsv4-y := nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o nfs4super.o nfs4file.o
> > >  	  dns_resolve.o nfs4trace.o
> > >  nfsv4-$(CONFIG_NFS_USE_LEGACY_DNS) += cache_lib.o
> > >  nfsv4-$(CONFIG_SYSCTL)	+= nfs4sysctl.o
> > > -nfsv4-$(CONFIG_NFS_V4_1)	+= pnfs.o pnfs_dev.o
> > > +nfsv4-$(CONFIG_NFS_V4_1)	+= pnfs.o pnfs_dev.o pnfs_nfsio.o
> > >  nfsv4-$(CONFIG_NFS_V4_2)	+= nfs42proc.o
> > >  
> > >  obj-$(CONFIG_PNFS_FILE_LAYOUT) += filelayout/
> > > diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
> > > index 7afb52f..bc36ed3 100644
> > > --- a/fs/nfs/filelayout/filelayout.c
> > > +++ b/fs/nfs/filelayout/filelayout.c
> > > @@ -118,13 +118,6 @@ static void filelayout_reset_read(struct nfs_pgio_header *hdr)
> > >  	}
> > >  }
> > >  
> > > -static void filelayout_fenceme(struct inode *inode, struct pnfs_layout_hdr *lo)
> > > -{
> > > -	if (!test_and_clear_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
> > > -		return;
> > > -	pnfs_return_layout(inode);
> > > -}
> > > -
> > >  static int filelayout_async_handle_error(struct rpc_task *task,
> > >  					 struct nfs4_state *state,
> > >  					 struct nfs_client *clp,
> > > @@ -339,16 +332,6 @@ static void filelayout_read_count_stats(struct rpc_task *task, void *data)
> > >  	rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
> > >  }
> > >  
> > > -static void filelayout_read_release(void *data)
> > > -{
> > > -	struct nfs_pgio_header *hdr = data;
> > > -	struct pnfs_layout_hdr *lo = hdr->lseg->pls_layout;
> > > -
> > > -	filelayout_fenceme(lo->plh_inode, lo);
> > > -	nfs_put_client(hdr->ds_clp);
> > > -	hdr->mds_ops->rpc_release(data);
> > > -}
> > > -
> > >  static int filelayout_write_done_cb(struct rpc_task *task,
> > >  				struct nfs_pgio_header *hdr)
> > >  {
> > > @@ -371,17 +354,6 @@ static int filelayout_write_done_cb(struct rpc_task *task,
> > >  	return 0;
> > >  }
> > >  
> > > -/* Fake up some data that will cause nfs_commit_release to retry the writes. */
> > > -static void prepare_to_resend_writes(struct nfs_commit_data *data)
> > > -{
> > > -	struct nfs_page *first = nfs_list_entry(data->pages.next);
> > > -
> > > -	data->task.tk_status = 0;
> > > -	memcpy(&data->verf.verifier, &first->wb_verf,
> > > -	       sizeof(data->verf.verifier));
> > > -	data->verf.verifier.data[0]++; /* ensure verifier mismatch */
> > > -}
> > > -
> > >  static int filelayout_commit_done_cb(struct rpc_task *task,
> > >  				     struct nfs_commit_data *data)
> > >  {
> > > @@ -393,7 +365,7 @@ static int filelayout_commit_done_cb(struct rpc_task *task,
> > >  
> > >  	switch (err) {
> > >  	case -NFS4ERR_RESET_TO_MDS:
> > > -		prepare_to_resend_writes(data);
> > > +		pnfs_generic_prepare_to_resend_writes(data);
> > >  		return -EAGAIN;
> > >  	case -EAGAIN:
> > >  		rpc_restart_call_prepare(task);
> > > @@ -451,16 +423,6 @@ static void filelayout_write_count_stats(struct rpc_task *task, void *data)
> > >  	rpc_count_iostats(task, NFS_SERVER(hdr->inode)->client->cl_metrics);
> > >  }
> > >  
> > > -static void filelayout_write_release(void *data)
> > > -{
> > > -	struct nfs_pgio_header *hdr = data;
> > > -	struct pnfs_layout_hdr *lo = hdr->lseg->pls_layout;
> > > -
> > > -	filelayout_fenceme(lo->plh_inode, lo);
> > > -	nfs_put_client(hdr->ds_clp);
> > > -	hdr->mds_ops->rpc_release(data);
> > > -}
> > > -
> > >  static void filelayout_commit_prepare(struct rpc_task *task, void *data)
> > >  {
> > >  	struct nfs_commit_data *wdata = data;
> > > @@ -471,14 +433,6 @@ static void filelayout_commit_prepare(struct rpc_task *task, void *data)
> > >  			task);
> > >  }
> > >  
> > > -static void filelayout_write_commit_done(struct rpc_task *task, void *data)
> > > -{
> > > -	struct nfs_commit_data *wdata = data;
> > > -
> > > -	/* Note this may cause RPC to be resent */
> > > -	wdata->mds_ops->rpc_call_done(task, data);
> > > -}
> > > -
> > >  static void filelayout_commit_count_stats(struct rpc_task *task, void *data)
> > >  {
> > >  	struct nfs_commit_data *cdata = data;
> > > @@ -486,35 +440,25 @@ static void filelayout_commit_count_stats(struct rpc_task *task, void *data)
> > >  	rpc_count_iostats(task, NFS_SERVER(cdata->inode)->client->cl_metrics);
> > >  }
> > >  
> > > -static void filelayout_commit_release(void *calldata)
> > > -{
> > > -	struct nfs_commit_data *data = calldata;
> > > -
> > > -	data->completion_ops->completion(data);
> > > -	pnfs_put_lseg(data->lseg);
> > > -	nfs_put_client(data->ds_clp);
> > > -	nfs_commitdata_release(data);
> > > -}
> > > -
> > >  static const struct rpc_call_ops filelayout_read_call_ops = {
> > >  	.rpc_call_prepare = filelayout_read_prepare,
> > >  	.rpc_call_done = filelayout_read_call_done,
> > >  	.rpc_count_stats = filelayout_read_count_stats,
> > > -	.rpc_release = filelayout_read_release,
> > > +	.rpc_release = pnfs_generic_rw_release,
> > >  };
> > >  
> > >  static const struct rpc_call_ops filelayout_write_call_ops = {
> > >  	.rpc_call_prepare = filelayout_write_prepare,
> > >  	.rpc_call_done = filelayout_write_call_done,
> > >  	.rpc_count_stats = filelayout_write_count_stats,
> > > -	.rpc_release = filelayout_write_release,
> > > +	.rpc_release = pnfs_generic_rw_release,
> > >  };
> > >  
> > >  static const struct rpc_call_ops filelayout_commit_call_ops = {
> > >  	.rpc_call_prepare = filelayout_commit_prepare,
> > > -	.rpc_call_done = filelayout_write_commit_done,
> > > +	.rpc_call_done = pnfs_generic_write_commit_done,
> > >  	.rpc_count_stats = filelayout_commit_count_stats,
> > > -	.rpc_release = filelayout_commit_release,
> > > +	.rpc_release = pnfs_generic_commit_release,
> > >  };
> > >  
> > >  static enum pnfs_try_status
> > > @@ -1004,33 +948,6 @@ static u32 select_bucket_index(struct nfs4_filelayout_segment *fl, u32 j)
> > >  		return j;
> > >  }
> > >  
> > > -/* The generic layer is about to remove the req from the commit list.
> > > - * If this will make the bucket empty, it will need to put the lseg reference.
> > > - * Note this is must be called holding the inode (/cinfo) lock
> > > - */
> > > -static void
> > > -filelayout_clear_request_commit(struct nfs_page *req,
> > > -				struct nfs_commit_info *cinfo)
> > > -{
> > > -	struct pnfs_layout_segment *freeme = NULL;
> > > -
> > > -	if (!test_and_clear_bit(PG_COMMIT_TO_DS, &req->wb_flags))
> > > -		goto out;
> > > -	cinfo->ds->nwritten--;
> > > -	if (list_is_singular(&req->wb_list)) {
> > > -		struct pnfs_commit_bucket *bucket;
> > > -
> > > -		bucket = list_first_entry(&req->wb_list,
> > > -					  struct pnfs_commit_bucket,
> > > -					  written);
> > > -		freeme = bucket->wlseg;
> > > -		bucket->wlseg = NULL;
> > > -	}
> > > -out:
> > > -	nfs_request_remove_commit_list(req, cinfo);
> > > -	pnfs_put_lseg_locked(freeme);
> > > -}
> > > -
> > >  static void
> > >  filelayout_mark_request_commit(struct nfs_page *req,
> > >  			       struct pnfs_layout_segment *lseg,
> > > @@ -1064,7 +981,7 @@ filelayout_mark_request_commit(struct nfs_page *req,
> > >  		 * is normally transferred to the COMMIT call and released
> > >  		 * there.  It could also be released if the last req is pulled
> > >  		 * off due to a rewrite, in which case it will be done in
> > > -		 * filelayout_clear_request_commit
> > > +		 * pnfs_generic_clear_request_commit
> > >  		 */
> > >  		buckets[i].wlseg = pnfs_get_lseg(lseg);
> > >  	}
> > > @@ -1142,97 +1059,11 @@ static int filelayout_initiate_commit(struct nfs_commit_data *data, int how)
> > >  				   &filelayout_commit_call_ops, how,
> > >  				   RPC_TASK_SOFTCONN);
> > >  out_err:
> > > -	prepare_to_resend_writes(data);
> > > -	filelayout_commit_release(data);
> > > +	pnfs_generic_prepare_to_resend_writes(data);
> > > +	pnfs_generic_commit_release(data);
> > >  	return -EAGAIN;
> > >  }
> > >  
> > > -static int
> > > -transfer_commit_list(struct list_head *src, struct list_head *dst,
> > > -		     struct nfs_commit_info *cinfo, int max)
> > > -{
> > > -	struct nfs_page *req, *tmp;
> > > -	int ret = 0;
> > > -
> > > -	list_for_each_entry_safe(req, tmp, src, wb_list) {
> > > -		if (!nfs_lock_request(req))
> > > -			continue;
> > > -		kref_get(&req->wb_kref);
> > > -		if (cond_resched_lock(cinfo->lock))
> > > -			list_safe_reset_next(req, tmp, wb_list);
> > > -		nfs_request_remove_commit_list(req, cinfo);
> > > -		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
> > > -		nfs_list_add_request(req, dst);
> > > -		ret++;
> > > -		if ((ret == max) && !cinfo->dreq)
> > > -			break;
> > > -	}
> > > -	return ret;
> > > -}
> > > -
> > > -/* Note called with cinfo->lock held. */
> > > -static int
> > > -filelayout_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
> > > -			       struct nfs_commit_info *cinfo,
> > > -			       int max)
> > > -{
> > > -	struct list_head *src = &bucket->written;
> > > -	struct list_head *dst = &bucket->committing;
> > > -	int ret;
> > > -
> > > -	ret = transfer_commit_list(src, dst, cinfo, max);
> > > -	if (ret) {
> > > -		cinfo->ds->nwritten -= ret;
> > > -		cinfo->ds->ncommitting += ret;
> > > -		bucket->clseg = bucket->wlseg;
> > > -		if (list_empty(src))
> > > -			bucket->wlseg = NULL;
> > > -		else
> > > -			pnfs_get_lseg(bucket->clseg);
> > > -	}
> > > -	return ret;
> > > -}
> > > -
> > > -/* Move reqs from written to committing lists, returning count of number moved.
> > > - * Note called with cinfo->lock held.
> > > - */
> > > -static int filelayout_scan_commit_lists(struct nfs_commit_info *cinfo,
> > > -					int max)
> > > -{
> > > -	int i, rv = 0, cnt;
> > > -
> > > -	for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
> > > -		cnt = filelayout_scan_ds_commit_list(&cinfo->ds->buckets[i],
> > > -						     cinfo, max);
> > > -		max -= cnt;
> > > -		rv += cnt;
> > > -	}
> > > -	return rv;
> > > -}
> > > -
> > > -/* Pull everything off the committing lists and dump into @dst */
> > > -static void filelayout_recover_commit_reqs(struct list_head *dst,
> > > -					   struct nfs_commit_info *cinfo)
> > > -{
> > > -	struct pnfs_commit_bucket *b;
> > > -	struct pnfs_layout_segment *freeme;
> > > -	int i;
> > > -
> > > -restart:
> > > -	spin_lock(cinfo->lock);
> > > -	for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
> > > -		if (transfer_commit_list(&b->written, dst, cinfo, 0)) {
> > > -			freeme = b->wlseg;
> > > -			b->wlseg = NULL;
> > > -			spin_unlock(cinfo->lock);
> > > -			pnfs_put_lseg(freeme);
> > > -			goto restart;
> > > -		}
> > > -	}
> > > -	cinfo->ds->nwritten = 0;
> > > -	spin_unlock(cinfo->lock);
> > > -}
> > > -
> > >  /* filelayout_search_commit_reqs - Search lists in @cinfo for the head reqest
> > >   *				   for @page
> > >   * @cinfo - commit info for current inode
> > > @@ -1263,108 +1094,14 @@ filelayout_search_commit_reqs(struct nfs_commit_info *cinfo, struct page *page)
> > >  	return NULL;
> > >  }
> > >  
> > > -static void filelayout_retry_commit(struct nfs_commit_info *cinfo, int idx)
> > > -{
> > > -	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
> > > -	struct pnfs_commit_bucket *bucket;
> > > -	struct pnfs_layout_segment *freeme;
> > > -	int i;
> > > -
> > > -	for (i = idx; i < fl_cinfo->nbuckets; i++) {
> > > -		bucket = &fl_cinfo->buckets[i];
> > > -		if (list_empty(&bucket->committing))
> > > -			continue;
> > > -		nfs_retry_commit(&bucket->committing, bucket->clseg, cinfo);
> > > -		spin_lock(cinfo->lock);
> > > -		freeme = bucket->clseg;
> > > -		bucket->clseg = NULL;
> > > -		spin_unlock(cinfo->lock);
> > > -		pnfs_put_lseg(freeme);
> > > -	}
> > > -}
> > > -
> > > -static unsigned int
> > > -alloc_ds_commits(struct nfs_commit_info *cinfo, struct list_head *list)
> > > -{
> > > -	struct pnfs_ds_commit_info *fl_cinfo;
> > > -	struct pnfs_commit_bucket *bucket;
> > > -	struct nfs_commit_data *data;
> > > -	int i;
> > > -	unsigned int nreq = 0;
> > > -
> > > -	fl_cinfo = cinfo->ds;
> > > -	bucket = fl_cinfo->buckets;
> > > -	for (i = 0; i < fl_cinfo->nbuckets; i++, bucket++) {
> > > -		if (list_empty(&bucket->committing))
> > > -			continue;
> > > -		data = nfs_commitdata_alloc();
> > > -		if (!data)
> > > -			break;
> > > -		data->ds_commit_index = i;
> > > -		spin_lock(cinfo->lock);
> > > -		data->lseg = bucket->clseg;
> > > -		bucket->clseg = NULL;
> > > -		spin_unlock(cinfo->lock);
> > > -		list_add(&data->pages, list);
> > > -		nreq++;
> > > -	}
> > > -
> > > -	/* Clean up on error */
> > > -	filelayout_retry_commit(cinfo, i);
> > > -	/* Caller will clean up entries put on list */
> > > -	return nreq;
> > > -}
> > > -
> > > -/* This follows nfs_commit_list pretty closely */
> > >  static int
> > >  filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
> > >  			   int how, struct nfs_commit_info *cinfo)
> > >  {
> > > -	struct nfs_commit_data *data, *tmp;
> > > -	LIST_HEAD(list);
> > > -	unsigned int nreq = 0;
> > > -
> > > -	if (!list_empty(mds_pages)) {
> > > -		data = nfs_commitdata_alloc();
> > > -		if (data != NULL) {
> > > -			data->lseg = NULL;
> > > -			list_add(&data->pages, &list);
> > > -			nreq++;
> > > -		} else {
> > > -			nfs_retry_commit(mds_pages, NULL, cinfo);
> > > -			filelayout_retry_commit(cinfo, 0);
> > > -			cinfo->completion_ops->error_cleanup(NFS_I(inode));
> > > -			return -ENOMEM;
> > > -		}
> > > -	}
> > > -
> > > -	nreq += alloc_ds_commits(cinfo, &list);
> > > -
> > > -	if (nreq == 0) {
> > > -		cinfo->completion_ops->error_cleanup(NFS_I(inode));
> > > -		goto out;
> > > -	}
> > > -
> > > -	atomic_add(nreq, &cinfo->mds->rpcs_out);
> > > -
> > > -	list_for_each_entry_safe(data, tmp, &list, pages) {
> > > -		list_del_init(&data->pages);
> > > -		if (!data->lseg) {
> > > -			nfs_init_commit(data, mds_pages, NULL, cinfo);
> > > -			nfs_initiate_commit(NFS_CLIENT(inode), data,
> > > -					    data->mds_ops, how, 0);
> > > -		} else {
> > > -			struct pnfs_commit_bucket *buckets;
> > > -
> > > -			buckets = cinfo->ds->buckets;
> > > -			nfs_init_commit(data, &buckets[data->ds_commit_index].committing, data->lseg, cinfo);
> > > -			filelayout_initiate_commit(data, how);
> > > -		}
> > > -	}
> > > -out:
> > > -	cinfo->ds->ncommitting = 0;
> > > -	return PNFS_ATTEMPTED;
> > > +	return pnfs_generic_commit_pagelist(inode, mds_pages, how, cinfo,
> > > +					    filelayout_initiate_commit);
> > >  }
> > > +
> > >  static struct nfs4_deviceid_node *
> > >  filelayout_alloc_deviceid_node(struct nfs_server *server,
> > >  		struct pnfs_device *pdev, gfp_t gfp_flags)
> > > @@ -1421,9 +1158,9 @@ static struct pnfs_layoutdriver_type filelayout_type = {
> > >  	.pg_write_ops		= &filelayout_pg_write_ops,
> > >  	.get_ds_info		= &filelayout_get_ds_info,
> > >  	.mark_request_commit	= filelayout_mark_request_commit,
> > > -	.clear_request_commit	= filelayout_clear_request_commit,
> > > -	.scan_commit_lists	= filelayout_scan_commit_lists,
> > > -	.recover_commit_reqs	= filelayout_recover_commit_reqs,
> > > +	.clear_request_commit	= pnfs_generic_clear_request_commit,
> > > +	.scan_commit_lists	= pnfs_generic_scan_commit_lists,
> > > +	.recover_commit_reqs	= pnfs_generic_recover_commit_reqs,
> > >  	.search_commit_reqs	= filelayout_search_commit_reqs,
> > >  	.commit_pagelist	= filelayout_commit_pagelist,
> > >  	.read_pagelist		= filelayout_read_pagelist,
> > > diff --git a/fs/nfs/filelayout/filelayout.h b/fs/nfs/filelayout/filelayout.h
> > > index 7c9f800..a5ce9b4 100644
> > > --- a/fs/nfs/filelayout/filelayout.h
> > > +++ b/fs/nfs/filelayout/filelayout.h
> > > @@ -119,17 +119,6 @@ FILELAYOUT_DEVID_NODE(struct pnfs_layout_segment *lseg)
> > >  	return &FILELAYOUT_LSEG(lseg)->dsaddr->id_node;
> > >  }
> > >  
> > > -static inline void
> > > -filelayout_mark_devid_invalid(struct nfs4_deviceid_node *node)
> > > -{
> > > -	u32 *p = (u32 *)&node->deviceid;
> > > -
> > > -	printk(KERN_WARNING "NFS: Deviceid [%x%x%x%x] marked out of use.\n",
> > > -		p[0], p[1], p[2], p[3]);
> > > -
> > > -	set_bit(NFS_DEVICEID_INVALID, &node->flags);
> > > -}
> > > -
> > >  static inline bool
> > >  filelayout_test_devid_invalid(struct nfs4_deviceid_node *node)
> > >  {
> > > diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c
> > > index bfecac7..d21080a 100644
> > > --- a/fs/nfs/filelayout/filelayoutdev.c
> > > +++ b/fs/nfs/filelayout/filelayoutdev.c
> > > @@ -708,7 +708,7 @@ nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
> > >  	if (ds == NULL) {
> > >  		printk(KERN_ERR "NFS: %s: No data server for offset index %d\n",
> > >  			__func__, ds_idx);
> > > -		filelayout_mark_devid_invalid(devid);
> > > +		pnfs_generic_mark_devid_invalid(devid);
> > >  		goto out;
> > >  	}
> > >  	smp_rmb();
> > > diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> > > index 9ae5b76..88eede0 100644
> > > --- a/fs/nfs/pnfs.h
> > > +++ b/fs/nfs/pnfs.h
> > > @@ -275,6 +275,23 @@ void nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node);
> > >  bool nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node);
> > >  void nfs4_deviceid_purge_client(const struct nfs_client *);
> > >  
> > > +/* pnfs_nfsio.c */
> > > +void pnfs_generic_clear_request_commit(struct nfs_page *req,
> > > +				       struct nfs_commit_info *cinfo);
> > > +void pnfs_generic_commit_release(void *calldata);
> > > +void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data);
> > > +void pnfs_generic_rw_release(void *data);
> > > +void pnfs_generic_recover_commit_reqs(struct list_head *dst,
> > > +				      struct nfs_commit_info *cinfo);
> > > +int pnfs_generic_commit_pagelist(struct inode *inode,
> > > +				 struct list_head *mds_pages,
> > > +				 int how,
> > > +				 struct nfs_commit_info *cinfo,
> > > +				 int (*initiate_commit)(struct nfs_commit_data *data,
> > > +							int how));
> > > +int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo, int max);
> > > +void pnfs_generic_write_commit_done(struct rpc_task *task, void *data);
> > > +
> > >  static inline struct nfs4_deviceid_node *
> > >  nfs4_get_deviceid(struct nfs4_deviceid_node *d)
> > >  {
> > > @@ -317,6 +334,12 @@ pnfs_get_ds_info(struct inode *inode)
> > >  	return ld->get_ds_info(inode);
> > >  }
> > >  
> > > +static inline void
> > > +pnfs_generic_mark_devid_invalid(struct nfs4_deviceid_node *node)
> > > +{
> > > +	set_bit(NFS_DEVICEID_INVALID, &node->flags);
> > > +}
> > > +
> > >  static inline bool
> > >  pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
> > >  			 struct nfs_commit_info *cinfo)
> > > diff --git a/fs/nfs/pnfs_nfsio.c b/fs/nfs/pnfs_nfsio.c
> > > new file mode 100644
> > > index 0000000..e5f841c
> > > --- /dev/null
> > > +++ b/fs/nfs/pnfs_nfsio.c
> > > @@ -0,0 +1,291 @@
> > > +/*
> > > + * Common NFS I/O  operations for the pnfs file based
> > > + * layout drivers.
> > > + *
> > > + * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
> > > + *
> > > + * Tom Haynes <loghyr@primarydata.com>
> > > + */
> > > +
> > > +#include <linux/nfs_fs.h>
> > > +#include <linux/nfs_page.h>
> > > +
> > > +#include "internal.h"
> > > +#include "pnfs.h"
> > > +
> > > +static void pnfs_generic_fenceme(struct inode *inode,
> > > +				 struct pnfs_layout_hdr *lo)
> > > +{
> > > +	if (!test_and_clear_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
> > > +		return;
> > > +	pnfs_return_layout(inode);
> > > +}
> > > +
> > > +void pnfs_generic_rw_release(void *data)
> > > +{
> > > +	struct nfs_pgio_header *hdr = data;
> > > +	struct pnfs_layout_hdr *lo = hdr->lseg->pls_layout;
> > > +
> > > +	pnfs_generic_fenceme(lo->plh_inode, lo);
> > > +	nfs_put_client(hdr->ds_clp);
> > > +	hdr->mds_ops->rpc_release(data);
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_rw_release);
> > > +
> > > +/* Fake up some data that will cause nfs_commit_release to retry the writes. */
> > > +void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data)
> > > +{
> > > +	struct nfs_page *first = nfs_list_entry(data->pages.next);
> > > +
> > > +	data->task.tk_status = 0;
> > > +	memcpy(&data->verf.verifier, &first->wb_verf,
> > > +	       sizeof(data->verf.verifier));
> > > +	data->verf.verifier.data[0]++; /* ensure verifier mismatch */
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_prepare_to_resend_writes);
> > > +
> > > +void pnfs_generic_write_commit_done(struct rpc_task *task, void *data)
> > > +{
> > > +	struct nfs_commit_data *wdata = data;
> > > +
> > > +	/* Note this may cause RPC to be resent */
> > > +	wdata->mds_ops->rpc_call_done(task, data);
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_write_commit_done);
> > > +
> > > +void pnfs_generic_commit_release(void *calldata)
> > > +{
> > > +	struct nfs_commit_data *data = calldata;
> > > +
> > > +	data->completion_ops->completion(data);
> > > +	pnfs_put_lseg(data->lseg);
> > > +	nfs_put_client(data->ds_clp);
> > > +	nfs_commitdata_release(data);
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
> > > +
> > > +/* The generic layer is about to remove the req from the commit list.
> > > + * If this will make the bucket empty, it will need to put the lseg reference.
> > > + * Note this is must be called holding the inode (/cinfo) lock
> > > + */
> > > +void
> > > +pnfs_generic_clear_request_commit(struct nfs_page *req,
> > > +				  struct nfs_commit_info *cinfo)
> > > +{
> > > +	struct pnfs_layout_segment *freeme = NULL;
> > > +
> > > +	if (!test_and_clear_bit(PG_COMMIT_TO_DS, &req->wb_flags))
> > > +		goto out;
> > > +	cinfo->ds->nwritten--;
> > > +	if (list_is_singular(&req->wb_list)) {
> > > +		struct pnfs_commit_bucket *bucket;
> > > +
> > > +		bucket = list_first_entry(&req->wb_list,
> > > +					  struct pnfs_commit_bucket,
> > > +					  written);
> > > +		freeme = bucket->wlseg;
> > > +		bucket->wlseg = NULL;
> > > +	}
> > > +out:
> > > +	nfs_request_remove_commit_list(req, cinfo);
> > > +	pnfs_put_lseg_locked(freeme);
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_clear_request_commit);
> > > +
> > > +static int
> > > +pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst,
> > > +				  struct nfs_commit_info *cinfo, int max)
> > > +{
> > > +	struct nfs_page *req, *tmp;
> > > +	int ret = 0;
> > > +
> > > +	list_for_each_entry_safe(req, tmp, src, wb_list) {
> > > +		if (!nfs_lock_request(req))
> > > +			continue;
> > > +		kref_get(&req->wb_kref);
> > > +		if (cond_resched_lock(cinfo->lock))
> > > +			list_safe_reset_next(req, tmp, wb_list);
> > > +		nfs_request_remove_commit_list(req, cinfo);
> > > +		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
> > > +		nfs_list_add_request(req, dst);
> > > +		ret++;
> > > +		if ((ret == max) && !cinfo->dreq)
> > > +			break;
> > > +	}
> > > +	return ret;
> > > +}
> > > +
> > > +/* Note called with cinfo->lock held. */
> > > +static int
> > > +pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
> > > +				 struct nfs_commit_info *cinfo,
> > > +				 int max)
> > > +{
> > > +	struct list_head *src = &bucket->written;
> > > +	struct list_head *dst = &bucket->committing;
> > > +	int ret;
> > > +
> > > +	ret = pnfs_generic_transfer_commit_list(src, dst, cinfo, max);
> > > +	if (ret) {
> > > +		cinfo->ds->nwritten -= ret;
> > > +		cinfo->ds->ncommitting += ret;
> > > +		bucket->clseg = bucket->wlseg;
> > > +		if (list_empty(src))
> > > +			bucket->wlseg = NULL;
> > > +		else
> > > +			pnfs_get_lseg(bucket->clseg);
> > > +	}
> > > +	return ret;
> > > +}
> > > +
> > > +/* Move reqs from written to committing lists, returning count of number moved.
> > > + * Note called with cinfo->lock held.
> > > + */
> > > +int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
> > > +				   int max)
> > > +{
> > > +	int i, rv = 0, cnt;
> > > +
> > > +	for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
> > > +		cnt = pnfs_generic_scan_ds_commit_list(&cinfo->ds->buckets[i],
> > > +						       cinfo, max);
> > > +		max -= cnt;
> > > +		rv += cnt;
> > > +	}
> > > +	return rv;
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_scan_commit_lists);
> > > +
> > > +/* Pull everything off the committing lists and dump into @dst */
> > > +void pnfs_generic_recover_commit_reqs(struct list_head *dst,
> > > +				      struct nfs_commit_info *cinfo)
> > > +{
> > > +	struct pnfs_commit_bucket *b;
> > > +	struct pnfs_layout_segment *freeme;
> > > +	int i;
> > > +
> > > +restart:
> > > +	spin_lock(cinfo->lock);
> > > +	for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
> > > +		if (pnfs_generic_transfer_commit_list(&b->written, dst,
> > > +						      cinfo, 0)) {
> > > +			freeme = b->wlseg;
> > > +			b->wlseg = NULL;
> > > +			spin_unlock(cinfo->lock);
> > > +			pnfs_put_lseg(freeme);
> > > +			goto restart;
> > > +		}
> > > +	}
> > > +	cinfo->ds->nwritten = 0;
> > > +	spin_unlock(cinfo->lock);
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);
> > > +
> > > +static void pnfs_generic_retry_commit(struct nfs_commit_info *cinfo, int idx)
> > > +{
> > > +	struct pnfs_ds_commit_info *fl_cinfo = cinfo->ds;
> > > +	struct pnfs_commit_bucket *bucket;
> > > +	struct pnfs_layout_segment *freeme;
> > > +	int i;
> > > +
> > > +	for (i = idx; i < fl_cinfo->nbuckets; i++) {
> > > +		bucket = &fl_cinfo->buckets[i];
> > > +		if (list_empty(&bucket->committing))
> > > +			continue;
> > > +		nfs_retry_commit(&bucket->committing, bucket->clseg, cinfo);
> > > +		spin_lock(cinfo->lock);
> > > +		freeme = bucket->clseg;
> > > +		bucket->clseg = NULL;
> > > +		spin_unlock(cinfo->lock);
> > > +		pnfs_put_lseg(freeme);
> > > +	}
> > > +}
> > > +
> > > +static unsigned int
> > > +pnfs_generic_alloc_ds_commits(struct nfs_commit_info *cinfo,
> > > +			      struct list_head *list)
> > > +{
> > > +	struct pnfs_ds_commit_info *fl_cinfo;
> > > +	struct pnfs_commit_bucket *bucket;
> > > +	struct nfs_commit_data *data;
> > > +	int i;
> > > +	unsigned int nreq = 0;
> > > +
> > > +	fl_cinfo = cinfo->ds;
> > > +	bucket = fl_cinfo->buckets;
> > > +	for (i = 0; i < fl_cinfo->nbuckets; i++, bucket++) {
> > > +		if (list_empty(&bucket->committing))
> > > +			continue;
> > > +		data = nfs_commitdata_alloc();
> > > +		if (!data)
> > > +			break;
> > > +		data->ds_commit_index = i;
> > > +		spin_lock(cinfo->lock);
> > > +		data->lseg = bucket->clseg;
> > > +		bucket->clseg = NULL;
> > > +		spin_unlock(cinfo->lock);
> > > +		list_add(&data->pages, list);
> > > +		nreq++;
> > > +	}
> > > +
> > > +	/* Clean up on error */
> > > +	pnfs_generic_retry_commit(cinfo, i);
> > > +	return nreq;
> > > +}
> > > +
> > > +/* This follows nfs_commit_list pretty closely */
> > > +int
> > > +pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
> > > +			     int how, struct nfs_commit_info *cinfo,
> > > +			     int (*initiate_commit)(struct nfs_commit_data *data,
> > > +						    int how))
> > > +{
> > > +	struct nfs_commit_data *data, *tmp;
> > > +	LIST_HEAD(list);
> > > +	unsigned int nreq = 0;
> > > +
> > > +	if (!list_empty(mds_pages)) {
> > > +		data = nfs_commitdata_alloc();
> > > +		if (data != NULL) {
> > > +			data->lseg = NULL;
> > > +			list_add(&data->pages, &list);
> > > +			nreq++;
> > > +		} else {
> > > +			nfs_retry_commit(mds_pages, NULL, cinfo);
> > > +			pnfs_generic_retry_commit(cinfo, 0);
> > > +			cinfo->completion_ops->error_cleanup(NFS_I(inode));
> > > +			return -ENOMEM;
> > > +		}
> > > +	}
> > > +
> > > +	nreq += pnfs_generic_alloc_ds_commits(cinfo, &list);
> > > +
> > > +	if (nreq == 0) {
> > > +		cinfo->completion_ops->error_cleanup(NFS_I(inode));
> > > +		goto out;
> > > +	}
> > > +
> > > +	atomic_add(nreq, &cinfo->mds->rpcs_out);
> > > +
> > > +	list_for_each_entry_safe(data, tmp, &list, pages) {
> > > +		list_del_init(&data->pages);
> > > +		if (!data->lseg) {
> > > +			nfs_init_commit(data, mds_pages, NULL, cinfo);
> > > +			nfs_initiate_commit(NFS_CLIENT(inode), data,
> > > +					    data->mds_ops, how, 0);
> > > +		} else {
> > > +			struct pnfs_commit_bucket *buckets;
> > > +
> > > +			buckets = cinfo->ds->buckets;
> > > +			nfs_init_commit(data,
> > > +					&buckets[data->ds_commit_index].committing,
> > > +					data->lseg,
> > > +					cinfo);
> > > +			initiate_commit(data, how);
> > > +		}
> > > +	}
> > > +out:
> > > +	cinfo->ds->ncommitting = 0;
> > > +	return PNFS_ATTEMPTED;
> > > +}
> > > +EXPORT_SYMBOL_GPL(pnfs_generic_commit_pagelist);
> > > 
> >