[PATCH 19/22] pnfs_submit: API change: remove pnfs_commit layoutget invocation

[Fred Isaman <iisaman@netapp.com>]

WARNING - this is an API change.

The layout driver's commit operation no longer takes an lseg.
This is because each nfs_page may or may not have an associated lseg.
It is the layout drivers task to send commits to the appropriate place.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
---
 fs/nfs/internal.h        |    2 +-
 fs/nfs/pagelist.c        |    5 ++-
 fs/nfs/pnfs.c            |   79 ++++++++-------------------------------------
 fs/nfs/pnfs.h            |   21 +++++-------
 fs/nfs/write.c           |   23 +++++++------
 include/linux/nfs_page.h |    3 +-
 6 files changed, 43 insertions(+), 90 deletions(-)

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 49c4ea8..f149452 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -288,7 +288,7 @@ extern int nfs_initiate_commit(struct nfs_write_data *data,
 extern int pnfs_initiate_commit(struct nfs_write_data *data,
 			       struct rpc_clnt *clnt,
 			       const struct rpc_call_ops *call_ops,
-			       int how);
+				int how, int pnfs);
 extern void nfs_write_prepare(struct rpc_task *task, void *calldata);
 extern void nfs_mark_list_commit(struct list_head *head);
 #ifdef CONFIG_MIGRATION
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 19ffdc5..52f6f6a 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -386,6 +386,7 @@ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
  * @idx_start: lower bound of page->index to scan
  * @npages: idx_start + npages sets the upper bound to scan.
  * @tag: tag to scan for
+ * @use_pnfs: will be set TRUE if commit needs to be handled by layout driver
  *
  * Moves elements from one of the inode request lists.
  * If the number of requests is set to 0, the entire address_space
@@ -395,7 +396,7 @@ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
  */
 int nfs_scan_list(struct nfs_inode *nfsi,
 		struct list_head *dst, pgoff_t idx_start,
-		unsigned int npages, int tag)
+		  unsigned int npages, int tag, int *use_pnfs)
 {
 	struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES];
 	struct nfs_page *req;
@@ -426,6 +427,8 @@ int nfs_scan_list(struct nfs_inode *nfsi,
 				radix_tree_tag_clear(&nfsi->nfs_page_tree,
 						req->wb_index, tag);
 				nfs_list_add_request(req, dst);
+				if (req->wb_lseg)
+					*use_pnfs = 1;
 				res++;
 				if (res == INT_MAX)
 					goto out;
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 5ccd406..4c3480b 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1673,19 +1673,11 @@ enum pnfs_try_status
 _pnfs_try_to_commit(struct nfs_write_data *data,
 		    const struct rpc_call_ops *call_ops, int how)
 {
-	struct inode *inode = data->inode;
-
-	if (!pnfs_enabled_sb(NFS_SERVER(inode))) {
-		dprintk("%s: Not using pNFS I/O\n", __func__);
-		return PNFS_NOT_ATTEMPTED;
-	} else {
-		/* data->call_ops and data->how set in nfs_commit_rpcsetup */
-		dprintk("%s: Utilizing pNFS I/O\n", __func__);
-		data->pdata.call_ops = call_ops;
-		data->pdata.pnfs_error = 0;
-		data->pdata.how = how;
-		return pnfs_commit(data, how);
-	}
+	dprintk("%s: Utilizing pNFS I/O\n", __func__);
+	data->pdata.call_ops = call_ops;
+	data->pdata.pnfs_error = 0;
+	data->pdata.how = how;
+	return pnfs_commit(data, how);
 }
 
 /* pNFS Commit callback function for all layout drivers */
@@ -1706,76 +1698,33 @@ pnfs_commit_done(struct nfs_write_data *data)
 		_pnfs_return_layout(data->inode, &range, NULL, RETURN_FILE,
 				    true);
 		pnfs_initiate_commit(data, NFS_CLIENT(data->inode),
-				     pdata->call_ops, pdata->how);
+				     pdata->call_ops, pdata->how, 1);
 	}
 }
 
 static enum pnfs_try_status
 pnfs_commit(struct nfs_write_data *data, int sync)
 {
-	int result;
 	struct nfs_inode *nfsi = NFS_I(data->inode);
 	struct nfs_server *nfss = NFS_SERVER(data->inode);
-	struct pnfs_layout_segment *lseg;
-	struct nfs_page *first, *last, *p;
-	int npages;
 	enum pnfs_try_status trypnfs;
-	u64 count;
 
 	dprintk("%s: Begin\n", __func__);
 
-	/* If the layout driver doesn't define its own commit function
-	 * use standard NFSv4 commit
-	 */
-	first = last = nfs_list_entry(data->pages.next);
-	npages = 0;
-	list_for_each_entry(p, &data->pages, wb_list) {
-		last = p;
-		npages++;
-	}
-	/* COMMIT indicates the whole file with offset = count = 0
-	 * whereas layout segments indicate whole file with offset = 0,
-	 * count = NFS4_MAX_UINT64.
+	/* We need to account for possibility that
+	 * each nfs_page can point to a different lseg (or be NULL).
+	 * For the immediate case of whole-file-only layouts, we at
+	 * least know there can be only a single lseg.
+	 * We still have to account for the possibility of some being NULL.
+	 * This will be done by passing the buck to the layout driver.
 	 */
-	count = ((npages - 1) << PAGE_CACHE_SHIFT) + first->wb_bytes +
-		 (first != last) ? last->wb_bytes : 0;
-	if (first->wb_offset == 0 && count == 0)
-		count = NFS4_MAX_UINT64;
-
-	/* FIXME: we really ought to keep the layout segment that we used
-	   to write the page around for committing it and never ask for a
-	   new one.  If it was recalled we better commit the data first
-	   before returning it, otherwise the data needs to be rewritten,
-	   either with a new layout or to the MDS */
-	result = _pnfs_update_layout(data->inode,
-				    NULL,
-				    count,
-				    first->wb_offset,
-				    IOMODE_RW,
-				    &lseg);
-	/* If no layout have been retrieved,
-	 * use standard NFSv4 commit
-	 */
-	if (result) {
-		dprintk("%s: Updating layout failed (%d), retry with NFS \n",
-			__func__, result);
-		trypnfs = PNFS_NOT_ATTEMPTED;
-		goto out;
-	}
-
-	dprintk("%s: Calling layout driver commit\n", __func__);
+	data->pdata.lseg = NULL;
 	if (!pnfs_use_rpc(nfss))
 		data->pdata.pnfsflags |= PNFS_NO_RPC;
-	data->pdata.lseg = lseg;
 	trypnfs = nfss->pnfs_curr_ld->ld_io_ops->commit(&nfsi->layout,
 							sync, data);
-	if (trypnfs == PNFS_NOT_ATTEMPTED) {
+	if (trypnfs == PNFS_NOT_ATTEMPTED)
 		data->pdata.pnfsflags &= ~PNFS_NO_RPC;
-		data->pdata.lseg = NULL;
-		put_lseg(lseg);
-	}
-
-out:
 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
 	return trypnfs;
 }
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index d1a4f42..78defc3 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -139,21 +139,18 @@ pnfs_try_to_commit(struct nfs_write_data *data,
 		   const struct rpc_call_ops *call_ops,
 		   int how)
 {
-	struct inode *inode = data->inode;
-	struct nfs_server *nfss = NFS_SERVER(inode);
 	enum pnfs_try_status ret;
 
-	/* Note that we check for "write_pagelist" and not for "commit"
-	   since if async writes were done and pages weren't marked as stable
-	   the commit method MUST be defined by the LD */
-	/* FIXME: write_pagelist should probably be mandated */
-	if (PNFS_EXISTS_LDIO_OP(nfss, write_pagelist))
-		ret = _pnfs_try_to_commit(data, call_ops, how);
-	else
-		ret = PNFS_NOT_ATTEMPTED;
-
+	/* Unlike in pnfs_try_to_write_data and pnfs_try_to_read_data,
+	 * we have no guarantee that all nfs_pages point to the same
+	 * lseg.  However, if we reach here, we are guaranteed that at
+	 * least one points to some lseg.
+	 */
+	ret = _pnfs_try_to_commit(data, call_ops, how);
 	if (ret == PNFS_ATTEMPTED)
-		nfs_inc_stats(inode, NFSIOS_PNFS_COMMIT);
+		nfs_inc_stats(data->inode, NFSIOS_PNFS_COMMIT);
+	else
+		_pnfs_clear_lseg_from_pages(&data->pages);
 	return ret;
 }
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 2302133..28e4907 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -527,7 +527,7 @@ nfs_need_commit(struct nfs_inode *nfsi)
  * The requests are *not* checked to ensure that they form a contiguous set.
  */
 static int
-nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
+nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages, int *use_pnfs)
 {
 	struct nfs_inode *nfsi = NFS_I(inode);
 	int ret;
@@ -535,7 +535,8 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, u
 	if (!nfs_need_commit(nfsi))
 		return 0;
 
-	ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
+	ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT,
+			    use_pnfs);
 	if (ret > 0)
 		nfsi->ncommit -= ret;
 	if (nfs_need_commit(NFS_I(inode)))
@@ -1334,9 +1335,10 @@ EXPORT_SYMBOL(nfs_initiate_commit);
 int pnfs_initiate_commit(struct nfs_write_data *data,
 			 struct rpc_clnt *clnt,
 			 const struct rpc_call_ops *call_ops,
-			 int how)
+			 int how, int pnfs)
 {
-	if (pnfs_try_to_commit(data, &nfs_commit_ops, how) == PNFS_ATTEMPTED)
+	if (pnfs &&
+	    (pnfs_try_to_commit(data, &nfs_commit_ops, how) == PNFS_ATTEMPTED))
 		return pnfs_get_write_status(data);
 
 	return nfs_initiate_commit(data, clnt, &nfs_commit_ops, how);
@@ -1347,7 +1349,7 @@ int pnfs_initiate_commit(struct nfs_write_data *data,
  */
 static int nfs_commit_rpcsetup(struct list_head *head,
 		struct nfs_write_data *data,
-		int how)
+		int how, int pnfs)
 {
 	struct nfs_page *first = nfs_list_entry(head->next);
 	struct inode *inode = first->wb_context->path.dentry->d_inode;
@@ -1374,7 +1376,7 @@ static int nfs_commit_rpcsetup(struct list_head *head,
 	data->args.context = first->wb_context;  /* used by commit done */
 
 	return pnfs_initiate_commit(data, NFS_CLIENT(inode), &nfs_commit_ops,
-				    how);
+				    how, pnfs);
 }
 
 /* Handle memory error during commit */
@@ -1398,7 +1400,7 @@ EXPORT_SYMBOL(nfs_mark_list_commit);
  * Commit dirty pages
  */
 static int
-nfs_commit_list(struct inode *inode, struct list_head *head, int how)
+nfs_commit_list(struct inode *inode, struct list_head *head, int how, int pnfs)
 {
 	struct nfs_write_data	*data;
 
@@ -1407,7 +1409,7 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how)
 		goto out_bad;
 
 	/* Set up the argument struct */
-	return nfs_commit_rpcsetup(head, data, how);
+	return nfs_commit_rpcsetup(head, data, how, pnfs);
  out_bad:
 	nfs_mark_list_commit(head);
 	nfs_commit_clear_lock(NFS_I(inode));
@@ -1495,14 +1497,15 @@ static int nfs_commit_inode(struct inode *inode, int how)
 	LIST_HEAD(head);
 	int may_wait = how & FLUSH_SYNC;
 	int res = 0;
+	int use_pnfs = 0;
 
 	if (!nfs_commit_set_lock(NFS_I(inode), may_wait))
 		goto out;
 	spin_lock(&inode->i_lock);
-	res = nfs_scan_commit(inode, &head, 0, 0);
+	res = nfs_scan_commit(inode, &head, 0, 0, &use_pnfs);
 	spin_unlock(&inode->i_lock);
 	if (res) {
-		int error = nfs_commit_list(inode, &head, how);
+		int error = nfs_commit_list(inode, &head, how, use_pnfs);
 		if (error < 0)
 			return error;
 		if (may_wait)
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index 18a455c..06e5157 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -83,7 +83,8 @@ extern	void nfs_release_request(struct nfs_page *req);
 
 
 extern	int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
-			  pgoff_t idx_start, unsigned int npages, int tag);
+			  pgoff_t idx_start, unsigned int npages, int tag,
+			  int *use_pnfs);
 extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 			     struct inode *inode,
 			     int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
-- 
1.6.6.1