CIFS: Implement cifs_strict_fsync

Invalidate inode mapping if we don't have at least Level II oplock in
cifs_strict_fsync. Also remove filemap_write_and_wait call from cifs_fsync
because it is previously called from vfs_fsync_range. Add file operations'
structures for strict cache mode.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 6c9ee80..8852470 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -44,13 +44,17 @@
 				inode->i_fop = &cifs_file_direct_nobrl_ops;
 			else
 				inode->i_fop = &cifs_file_direct_ops;
+		} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
+			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
+				inode->i_fop = &cifs_file_strict_nobrl_ops;
+			else
+				inode->i_fop = &cifs_file_strict_ops;
 		} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
 			inode->i_fop = &cifs_file_nobrl_ops;
 		else { /* not direct, send byte range locks */
 			inode->i_fop = &cifs_file_ops;
 		}
 
-
 		/* check if server can support readpages */
 		if (cifs_sb_master_tcon(cifs_sb)->ses->server->maxBuf <
 				PAGE_CACHE_SIZE + MAX_CIFS_HDR_SIZE)
@@ -1679,7 +1683,7 @@
 /*
  * Zap the cache. Called when invalid_mapping flag is set.
  */
-static void
+void
 cifs_invalidate_mapping(struct inode *inode)
 {
 	int rc;