From ba827c9abb0b413a4c87b68c87d39b310fc01101 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Fri, 20 Mar 2020 18:34:33 -0400
Subject: pNFS: Enable per-layout segment commit structures

Enable adding and lookup of per-layout segment commits in filelayout
and flexfilelayout.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/pnfs_nfs.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 71 insertions(+), 6 deletions(-)

(limited to 'fs/nfs/pnfs_nfs.c')

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index edad251a6a48..5b426a090ee3 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -118,6 +118,66 @@ pnfs_free_commit_array(struct pnfs_commit_array *p)
 }
 EXPORT_SYMBOL_GPL(pnfs_free_commit_array);
 
+static struct pnfs_commit_array *
+pnfs_find_commit_array_by_lseg(struct pnfs_ds_commit_info *fl_cinfo,
+		struct pnfs_layout_segment *lseg)
+{
+	struct pnfs_commit_array *array;
+
+	list_for_each_entry_rcu(array, &fl_cinfo->commits, cinfo_list) {
+		if (array->lseg == lseg)
+			return array;
+	}
+	return NULL;
+}
+
+struct pnfs_commit_array *
+pnfs_add_commit_array(struct pnfs_ds_commit_info *fl_cinfo,
+		struct pnfs_commit_array *new,
+		struct pnfs_layout_segment *lseg)
+{
+	struct pnfs_commit_array *array;
+
+	array = pnfs_find_commit_array_by_lseg(fl_cinfo, lseg);
+	if (array)
+		return array;
+	new->lseg = lseg;
+	refcount_set(&new->refcount, 1);
+	list_add_rcu(&new->cinfo_list, &fl_cinfo->commits);
+	list_add(&new->lseg_list, &lseg->pls_commits);
+	return new;
+}
+EXPORT_SYMBOL_GPL(pnfs_add_commit_array);
+
+static void
+pnfs_setup_ds_info(struct pnfs_ds_commit_info *fl_cinfo,
+		struct pnfs_layout_segment *lseg)
+{
+	struct inode *inode = lseg->pls_layout->plh_inode;
+	struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
+
+	if (ld->setup_ds_info != NULL)
+		ld->setup_ds_info(fl_cinfo, lseg);
+}
+
+static struct pnfs_commit_array *
+pnfs_lookup_commit_array(struct pnfs_ds_commit_info *fl_cinfo,
+		struct pnfs_layout_segment *lseg)
+{
+	struct pnfs_commit_array *array;
+
+	rcu_read_lock();
+	array = pnfs_find_commit_array_by_lseg(fl_cinfo, lseg);
+	if (!array) {
+		rcu_read_unlock();
+		pnfs_setup_ds_info(fl_cinfo, lseg);
+		rcu_read_lock();
+		array = pnfs_find_commit_array_by_lseg(fl_cinfo, lseg);
+	}
+	rcu_read_unlock();
+	return array;
+}
+
 static void
 pnfs_release_commit_array_locked(struct pnfs_commit_array *array)
 {
@@ -1082,17 +1142,18 @@ pnfs_layout_mark_request_commit(struct nfs_page *req,
 				u32 ds_commit_idx)
 {
 	struct list_head *list;
+	struct pnfs_commit_array *array;
 	struct pnfs_commit_bucket *buckets;
 
 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
-	buckets = cinfo->ds->buckets;
+	array = pnfs_lookup_commit_array(cinfo->ds, lseg);
+	if (!array)
+		goto out_resched;
+	buckets = array->buckets;
 	list = &buckets[ds_commit_idx].written;
 	if (list_empty(list)) {
-		if (!pnfs_is_valid_lseg(lseg)) {
-			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
-			cinfo->completion_ops->resched_write(cinfo, req);
-			return;
-		}
+		if (!pnfs_is_valid_lseg(lseg))
+			goto out_resched;
 		/* Non-empty buckets hold a reference on the lseg.  That ref
 		 * is normally transferred to the COMMIT call and released
 		 * there.  It could also be released if the last req is pulled
@@ -1108,6 +1169,10 @@ pnfs_layout_mark_request_commit(struct nfs_page *req,
 	nfs_request_add_commit_list_locked(req, list, cinfo);
 	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 	nfs_mark_page_unstable(req->wb_page, cinfo);
+	return;
+out_resched:
+	mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+	cinfo->completion_ops->resched_write(cinfo, req);
 }
 EXPORT_SYMBOL_GPL(pnfs_layout_mark_request_commit);
 
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