ceph: fix reading inline data when i_size > PAGE_SIZE

when inode has inline data but its size > PAGE_SIZE (it was truncated
to larger size), previous direct read code return -EIO. This patch adds
code to return zeros for data whose offset > PAGE_SIZE.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index c81c0e00..7d05e37 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -196,17 +196,22 @@
 	u64 len = PAGE_CACHE_SIZE;
 
 	if (off >= i_size_read(inode)) {
-		zero_user_segment(page, err, PAGE_CACHE_SIZE);
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
 		SetPageUptodate(page);
 		return 0;
 	}
 
-	/*
-	 * Uptodate inline data should have been added into page cache
-	 * while getting Fcr caps.
-	 */
-	if (ci->i_inline_version != CEPH_INLINE_NONE)
-		return -EINVAL;
+	if (ci->i_inline_version != CEPH_INLINE_NONE) {
+		/*
+		 * Uptodate inline data should have been added
+		 * into page cache while getting Fcr caps.
+		 */
+		if (off == 0)
+			return -EINVAL;
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+		SetPageUptodate(page);
+		return 0;
+	}
 
 	err = ceph_readpage_from_fscache(inode, page);
 	if (err == 0)