- /*
- * Statahead entry reference rules:
- *
- * 1) When statahead entry is initialized, its reference is set as 2.
- * One reference is used by the directory scanner. When the scanner
- * searches the statahead cache for the given name, it can perform
- * lockless hash lookup (only the scanner can remove entry from hash
- * list), and once found, it needn't to call "atomic_inc()" for the
- * entry reference. So the performance is improved. After using the
- * statahead entry, the scanner will call "atomic_dec()" to drop the
- * reference held when initialization. If it is the last reference,
- * the statahead entry will be freed.
- *
- * 2) All other threads, including statahead thread and ptlrpcd thread,
- * when they process the statahead entry, the reference for target
- * should be held to guarantee the entry will not be released by the
- * directory scanner. After processing the entry, these threads will
- * drop the entry reference. If it is the last reference, the entry
- * will be freed.
- *
- * The second reference when initializes the statahead entry is used
- * by the statahead thread, following the rule 2).
- */
- atomic_set(&entry->se_refcount, 2);
- entry->se_stat = SA_ENTRY_INIT;