1 files changed, 11 insertions, 5 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d53857b148e2..106aca388ebc 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -85,6 +85,9 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
         atomic_set(&req->wb_complete, 0);
         req->wb_index   = page->index;
         page_cache_get(page);
+        BUG_ON(PagePrivate(page));
+        BUG_ON(!PageLocked(page));
+        BUG_ON(page->mapping->host != inode);
         req->wb_offset  = offset;
         req->wb_pgbase  = offset;
         req->wb_bytes   = count;
@@ -132,9 +135,11 @@ void nfs_clear_page_writeback(struct nfs_page *req)
 {
         struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
 
-        spin_lock(&nfsi->req_lock);
-        radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);
-        spin_unlock(&nfsi->req_lock);
+        if (req->wb_page != NULL) {
+                spin_lock(&nfsi->req_lock);
+                radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);
+                spin_unlock(&nfsi->req_lock);
+        }
         nfs_unlock_request(req);
 }
 
@@ -147,8 +152,9 @@ void nfs_clear_page_writeback(struct nfs_page *req)
  */
 void nfs_clear_request(struct nfs_page *req)
 {
-        if (req->wb_page) {
-                page_cache_release(req->wb_page);
+        struct page *page = req->wb_page;
+        if (page != NULL) {
+                page_cache_release(page);
                 req->wb_page = NULL;
         }
 }