nfs: mark nfs_page reqs with flag for extra ref

Change the use of PG_INODE_REF - set it when taking extra reference on
subrequests and take care to only release once for each request.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

2 files changed, 9 insertions, 3 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index b6ee3a6ee96d..7368b2130a41 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -251,8 +251,10 @@ nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
                 /* grab extra ref if head request has extra ref from
                  * the write/commit path to handle handoff between write
                  * and commit lists */
-                if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags))
+                if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
+                        set_bit(PG_INODE_REF, &req->wb_flags);
                         kref_get(&req->wb_kref);
+                }
         }
 }
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 98ff061ccaf3..8e5745a4deff 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -448,7 +448,9 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
                 set_page_private(req->wb_page, (unsigned long)req);
         }
         nfsi->npages++;
-        set_bit(PG_INODE_REF, &req->wb_flags);
+        /* this a head request for a page group - mark it as having an
+         * extra reference so sub groups can follow suit */
+        WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
         kref_get(&req->wb_kref);
         spin_unlock(&inode->i_lock);
 }
@@ -474,7 +476,9 @@ static void nfs_inode_remove_request(struct nfs_page *req)
                 nfsi->npages--;
                 spin_unlock(&inode->i_lock);
         }
-        nfs_release_request(req);
+
+        if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags))
+                nfs_release_request(req);
 }
 
 static void