/* sync the superblock to buffers */
sb = inode->i_sb;
lock_super(sb);
- if (sb->s_op->write_super)
+ if (sb->s_dirt && sb->s_op->write_super)
sb->s_op->write_super(sb);
unlock_super(sb);
* before performing the write.
*
* SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
- * range which are not presently under writeback.
+ * range which are not presently under writeback. Note that this may block for
+ * significant periods due to exhaustion of disk request structures.
*
* SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
* after performing the write.