ceph fscache: Introduce a routine for uncaching single no data page from fscache

Signed-off-by: Li Wang <liwang@ubuntukylin.com>
Reviewed-by: Milosz Tanski <milosz@adfin.com>

fs/ceph/cache.h

@@ -67,6 +67,14 @@ static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
 	return fscache_maybe_release_page(ci->fscache, page, gfp);
 }
 
+static inline void ceph_fscache_readpage_cancel(struct inode *inode,
+						struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	if (fscache_cookie_valid(ci->fscache) && PageFsCache(page))
+		__fscache_uncache_page(ci->fscache, page);
+}
+
 static inline void ceph_fscache_readpages_cancel(struct inode *inode,
 						 struct list_head *pages)
 {
@@ -145,6 +153,11 @@ static inline int ceph_release_fscache_page(struct page *page, gfp_t gfp)
 	return 1;
 }
 
+static inline void ceph_fscache_readpage_cancel(struct inode *inode,
+						struct page *page)
+{
+}
+
 static inline void ceph_fscache_readpages_cancel(struct inode *inode,
 						 struct list_head *pages)
 {