NFS: create struct nfs_commit_info

It is COMMIT that is handled the most differently between
the paged and direct paths.  Create a structure that encapsulates
everything either path needs to know about the commit state.

We could use void to hide some of the layout driver stuff, but
Trond suggests pulling it out to ensure type checking, given the
huge changes being made, and the fact that it doesn't interfere
with other drivers.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 93 insertions, 65 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 2500f1c..18bf700 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -452,65 +452,79 @@ nfs_mark_request_dirty(struct nfs_page *req)
 /**
  * nfs_request_add_commit_list - add request to a commit list
  * @req: pointer to a struct nfs_page
- * @head: commit list head
+ * @dst: commit list head
+ * @cinfo: holds list lock and accounting info
  *
- * This sets the PG_CLEAN bit, updates the inode global count of
+ * This sets the PG_CLEAN bit, updates the cinfo count of
  * number of outstanding requests requiring a commit as well as
  * the MM page stats.
  *
- * The caller must _not_ hold the inode->i_lock, but must be
+ * The caller must _not_ hold the cinfo->lock, but must be
  * holding the nfs_page lock.
  */
 void
-nfs_request_add_commit_list(struct nfs_page *req, struct list_head *head)
+nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
+			    struct nfs_commit_info *cinfo)
 {
-	struct inode *inode = req->wb_context->dentry->d_inode;
-
 	set_bit(PG_CLEAN, &(req)->wb_flags);
-	spin_lock(&inode->i_lock);
-	nfs_list_add_request(req, head);
-	NFS_I(inode)->ncommit++;
-	spin_unlock(&inode->i_lock);
+	spin_lock(cinfo->lock);
+	nfs_list_add_request(req, dst);
+	cinfo->mds->ncommit++;
+	spin_unlock(cinfo->lock);
 	inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 	inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
-	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+	__mark_inode_dirty(req->wb_context->dentry->d_inode, I_DIRTY_DATASYNC);
 }
 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 
 /**
  * nfs_request_remove_commit_list - Remove request from a commit list
  * @req: pointer to a nfs_page
+ * @cinfo: holds list lock and accounting info
  *
- * This clears the PG_CLEAN bit, and updates the inode global count of
+ * This clears the PG_CLEAN bit, and updates the cinfo's count of
  * number of outstanding requests requiring a commit
  * It does not update the MM page stats.
  *
- * The caller _must_ hold the inode->i_lock and the nfs_page lock.
+ * The caller _must_ hold the cinfo->lock and the nfs_page lock.
  */
 void
-nfs_request_remove_commit_list(struct nfs_page *req)
+nfs_request_remove_commit_list(struct nfs_page *req,
+			       struct nfs_commit_info *cinfo)
 {
-	struct inode *inode = req->wb_context->dentry->d_inode;
-
 	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 		return;
 	nfs_list_remove_request(req);
-	NFS_I(inode)->ncommit--;
+	cinfo->mds->ncommit--;
 }
 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 
+static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
+				      struct inode *inode)
+{
+	cinfo->lock = &inode->i_lock;
+	cinfo->mds = &NFS_I(inode)->commit_info;
+	cinfo->ds = pnfs_get_ds_info(inode);
+}
+
+void nfs_init_cinfo(struct nfs_commit_info *cinfo,
+		    struct inode *inode,
+		    struct nfs_direct_req *dreq)
+{
+	nfs_init_cinfo_from_inode(cinfo, inode);
+}
+EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 
 /*
  * Add a request to the inode's commit list.
  */
 static void
-nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
+nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
+			struct nfs_commit_info *cinfo)
 {
-	struct inode *inode = req->wb_context->dentry->d_inode;
-
-	if (pnfs_mark_request_commit(req, lseg))
+	if (pnfs_mark_request_commit(req, lseg, cinfo))
 		return;
-	nfs_request_add_commit_list(req, &NFS_I(inode)->commit_list);
+	nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
 }
 
 static void
@@ -525,11 +539,13 @@ nfs_clear_request_commit(struct nfs_page *req)
 {
 	if (test_bit(PG_CLEAN, &req->wb_flags)) {
 		struct inode *inode = req->wb_context->dentry->d_inode;
+		struct nfs_commit_info cinfo;
 
-		if (!pnfs_clear_request_commit(req)) {
-			spin_lock(&inode->i_lock);
-			nfs_request_remove_commit_list(req);
-			spin_unlock(&inode->i_lock);
+		nfs_init_cinfo_from_inode(&cinfo, inode);
+		if (!pnfs_clear_request_commit(req, &cinfo)) {
+			spin_lock(cinfo.lock);
+			nfs_request_remove_commit_list(req, &cinfo);
+			spin_unlock(cinfo.lock);
 		}
 		nfs_clear_page_commit(req->wb_page);
 	}
@@ -545,7 +561,8 @@ int nfs_write_need_commit(struct nfs_write_data *data)
 
 #else
 static void
-nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
+nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
+			struct nfs_commit_info *cinfo)
 {
 }
 
@@ -564,10 +581,12 @@ int nfs_write_need_commit(struct nfs_write_data *data)
 
 static void nfs_write_completion(struct nfs_pgio_header *hdr)
 {
+	struct nfs_commit_info cinfo;
 	unsigned long bytes = 0;
 
 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 		goto out;
+	nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 	while (!list_empty(&hdr->pages)) {
 		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 		struct page *page = req->wb_page;
@@ -585,7 +604,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr)
 			goto next;
 		}
 		if (test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags)) {
-			nfs_mark_request_commit(req, hdr->lseg);
+			nfs_mark_request_commit(req, hdr->lseg, &cinfo);
 			goto next;
 		}
 remove_req:
@@ -599,16 +618,16 @@ out:
 }
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-static int
-nfs_need_commit(struct nfs_inode *nfsi)
+static unsigned long
+nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 {
-	return nfsi->ncommit > 0;
+	return cinfo->mds->ncommit;
 }
 
-/* i_lock held by caller */
+/* cinfo->lock held by caller */
 static int
-nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max,
-		spinlock_t *lock)
+nfs_scan_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;
@@ -616,9 +635,9 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max,
 	list_for_each_entry_safe(req, tmp, src, wb_list) {
 		if (!nfs_lock_request(req))
 			continue;
-		if (cond_resched_lock(lock))
+		if (cond_resched_lock(cinfo->lock))
 			list_safe_reset_next(req, tmp, wb_list);
-		nfs_request_remove_commit_list(req);
+		nfs_request_remove_commit_list(req, cinfo);
 		nfs_list_add_request(req, dst);
 		ret++;
 		if (ret == max)
@@ -630,37 +649,38 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max,
 /*
  * nfs_scan_commit - Scan an inode for commit requests
  * @inode: NFS inode to scan
- * @dst: destination list
+ * @dst: mds destination list
+ * @cinfo: mds and ds lists of reqs ready to commit
  *
  * Moves requests from the inode's 'commit' request list.
  * 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)
+nfs_scan_commit(struct inode *inode, struct list_head *dst,
+		struct nfs_commit_info *cinfo)
 {
-	struct nfs_inode *nfsi = NFS_I(inode);
 	int ret = 0;
 
-	spin_lock(&inode->i_lock);
-	if (nfsi->ncommit > 0) {
+	spin_lock(cinfo->lock);
+	if (cinfo->mds->ncommit > 0) {
 		const int max = INT_MAX;
 
-		ret = nfs_scan_commit_list(&nfsi->commit_list, dst, max,
-				&inode->i_lock);
-		ret += pnfs_scan_commit_lists(inode, max - ret,
-				&inode->i_lock);
+		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
+					   cinfo, max);
+		ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
 	}
-	spin_unlock(&inode->i_lock);
+	spin_unlock(cinfo->lock);
 	return ret;
 }
 
 #else
-static inline int nfs_need_commit(struct nfs_inode *nfsi)
+static unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 {
 	return 0;
 }
 
-static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst)
+static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst,
+				  struct nfs_commit_info *cinfo)
 {
 	return 0;
 }
@@ -929,7 +949,7 @@ EXPORT_SYMBOL_GPL(nfs_initiate_write);
  */
 static void nfs_write_rpcsetup(struct nfs_write_data *data,
 		unsigned int count, unsigned int offset,
-		int how)
+		int how, struct nfs_commit_info *cinfo)
 {
 	struct nfs_page *req = data->header->req;
 
@@ -950,7 +970,7 @@ static void nfs_write_rpcsetup(struct nfs_write_data *data,
 	case 0:
 		break;
 	case FLUSH_COND_STABLE:
-		if (nfs_need_commit(NFS_I(data->header->inode)))
+		if (nfs_reqs_to_commit(cinfo))
 			break;
 	default:
 		data->args.stable = NFS_FILE_SYNC;
@@ -1034,12 +1054,14 @@ static int nfs_flush_multi(struct nfs_pageio_descriptor *desc,
 	unsigned int offset;
 	int requests = 0;
 	int ret = 0;
+	struct nfs_commit_info cinfo;
 
+	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
 	nfs_list_remove_request(req);
 	nfs_list_add_request(req, &hdr->pages);
 
 	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
-	    (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
+	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo) ||
 	     desc->pg_count > wsize))
 		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 
@@ -1053,7 +1075,7 @@ static int nfs_flush_multi(struct nfs_pageio_descriptor *desc,
 		if (!data)
 			goto out_bad;
 		data->pages.pagevec[0] = page;
-		nfs_write_rpcsetup(data, len, offset, desc->pg_ioflags);
+		nfs_write_rpcsetup(data, len, offset, desc->pg_ioflags, &cinfo);
 		list_add(&data->list, &hdr->rpc_list);
 		requests++;
 		nbytes -= len;
@@ -1088,6 +1110,7 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
 	struct nfs_write_data	*data;
 	struct list_head *head = &desc->pg_list;
 	int ret = 0;
+	struct nfs_commit_info cinfo;
 
 	data = nfs_writedata_alloc(hdr, nfs_page_array_len(desc->pg_base,
 							   desc->pg_count));
@@ -1097,6 +1120,7 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
 		goto out;
 	}
 
+	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
 	pages = data->pages.pagevec;
 	while (!list_empty(head)) {
 		req = nfs_list_entry(head->next);
@@ -1106,11 +1130,11 @@ static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
 	}
 
 	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
-	    (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
+	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
 		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 
 	/* Set up the argument struct */
-	nfs_write_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags);
+	nfs_write_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
 	list_add(&data->list, &hdr->rpc_list);
 	desc->pg_rpc_callops = &nfs_write_common_ops;
 out:
@@ -1417,14 +1441,15 @@ void nfs_init_commit(struct nfs_commit_data *data,
 EXPORT_SYMBOL_GPL(nfs_init_commit);
 
 void nfs_retry_commit(struct list_head *page_list,
-		      struct pnfs_layout_segment *lseg)
+		      struct pnfs_layout_segment *lseg,
+		      struct nfs_commit_info *cinfo)
 {
 	struct nfs_page *req;
 
 	while (!list_empty(page_list)) {
 		req = nfs_list_entry(page_list->next);
 		nfs_list_remove_request(req);
-		nfs_mark_request_commit(req, lseg);
+		nfs_mark_request_commit(req, lseg, cinfo);
 		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 		dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
 			     BDI_RECLAIMABLE);
@@ -1437,7 +1462,8 @@ EXPORT_SYMBOL_GPL(nfs_retry_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,
+		struct nfs_commit_info *cinfo)
 {
 	struct nfs_commit_data	*data;
 
@@ -1450,7 +1476,7 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how)
 	nfs_init_commit(data, head, NULL);
 	return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops, how);
  out_bad:
-	nfs_retry_commit(head, NULL);
+	nfs_retry_commit(head, NULL, cinfo);
 	nfs_commit_clear_lock(NFS_I(inode));
 	return -ENOMEM;
 }
@@ -1524,30 +1550,32 @@ static const struct rpc_call_ops nfs_commit_ops = {
 };
 
 static int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
-				   int how)
+				   int how, struct nfs_commit_info *cinfo)
 {
 	int status;
 
-	status = pnfs_commit_list(inode, head, how);
+	status = pnfs_commit_list(inode, head, how, cinfo);
 	if (status == PNFS_NOT_ATTEMPTED)
-		status = nfs_commit_list(inode, head, how);
+		status = nfs_commit_list(inode, head, how, cinfo);
 	return status;
 }
 
 int nfs_commit_inode(struct inode *inode, int how)
 {
 	LIST_HEAD(head);
+	struct nfs_commit_info cinfo;
 	int may_wait = how & FLUSH_SYNC;
 	int res;
 
 	res = nfs_commit_set_lock(NFS_I(inode), may_wait);
 	if (res <= 0)
 		goto out_mark_dirty;
-	res = nfs_scan_commit(inode, &head);
+	nfs_init_cinfo_from_inode(&cinfo, inode);
+	res = nfs_scan_commit(inode, &head, &cinfo);
 	if (res) {
 		int error;
 
-		error = nfs_generic_commit_list(inode, &head, how);
+		error = nfs_generic_commit_list(inode, &head, how, &cinfo);
 		if (error < 0)
 			return error;
 		if (!may_wait)
@@ -1578,14 +1606,14 @@ static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_contr
 	int ret = 0;
 
 	/* no commits means nothing needs to be done */
-	if (!nfsi->ncommit)
+	if (!nfsi->commit_info.ncommit)
 		return ret;
 
 	if (wbc->sync_mode == WB_SYNC_NONE) {
 		/* Don't commit yet if this is a non-blocking flush and there
 		 * are a lot of outstanding writes for this mapping.
 		 */
-		if (nfsi->ncommit <= (nfsi->npages >> 1))
+		if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1))
 			goto out_mark_dirty;
 
 		/* don't wait for the COMMIT response */