ocfs2: Update syncing after splicing to match generic version

Update ocfs2 specific splicing code to use generic syncing helper. The sync now
does not happen under rw_lock because generic_write_sync() acquires i_mutex
which ranks above rw_lock. That should not matter because standard fsync path
does not hold it either.
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
CC: ocfs2-devel@oss.oracle.com
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ocfs2/file.c

@@ -1993,31 +1993,16 @@ static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
 
 	if (ret > 0) {
 		unsigned long nr_pages;
-
-		*ppos += ret;
-		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-
-		/*
-		 * If file or inode is SYNC and we actually wrote some data,
-		 * sync it.
-		 */
-		if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
 		int err;
 
-			mutex_lock(&inode->i_mutex);
-			err = ocfs2_rw_lock(inode, 1);
-			if (err < 0) {
-				mlog_errno(err);
-			} else {
-				err = generic_osync_inode(inode, mapping,
-						  OSYNC_METADATA|OSYNC_DATA);
-				ocfs2_rw_unlock(inode, 1);
-			}
-			mutex_unlock(&inode->i_mutex);
+		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
+		err = generic_write_sync(out, *ppos, ret);
 		if (err)
 			ret = err;
-		}
+		else
+			*ppos += ret;
+
 		balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
 	}