upcall_cache.c

来自「lustre 1.6.5 source code」· C语言 代码 · 共 519 行 · 第 1/2 页

        list_for_each_entry_safe(entry, next, head, ue_hash) {
                /* check invalid & expired items */
                if (check_unlink_entry(entry))
                        continue;
                if (entry->ue_key == key) {
                        found = 1;
                        break;
                }
        }

        if (!found) { /* didn't find it */
                if (!new) {
                        spin_unlock(&hash->uc_lock);
                        new = alloc_entry(key);
                        if (!new) {
                                CERROR("fail to alloc entry\n");
                                RETURN(ERR_PTR(-ENOMEM));
                        }
                        goto find_again;
                } else {
                        list_add(&new->ue_hash, head);
                        entry = new;
                }
        } else {
                if (new) {
                        free_entry(new);
                        new = NULL;
                }
                list_move(&entry->ue_hash, head);
        }
        get_entry(entry);

        /* acquire for new one */
        if (UC_CACHE_IS_NEW(entry)) {
                UC_CACHE_SET_ACQUIRING(entry);
                UC_CACHE_CLEAR_NEW(entry);
                entry->ue_acquire_expire = jiffies + hash->uc_acquire_expire;
                spin_unlock(&hash->uc_lock);
                rc = refresh_entry(hash, entry);
                spin_lock(&hash->uc_lock);
                if (rc < 0) {
                        UC_CACHE_CLEAR_ACQUIRING(entry);
                        UC_CACHE_SET_INVALID(entry);
                }
                /* fall through */
        }
        /* someone (and only one) is doing upcall upon
         * this item, just wait it complete
         */
        if (UC_CACHE_IS_ACQUIRING(entry)) {
                init_waitqueue_entry(&wait, current);
                add_wait_queue(&entry->ue_waitq, &wait);
                set_current_state(TASK_INTERRUPTIBLE);
                spin_unlock(&hash->uc_lock);

                schedule_timeout(hash->uc_acquire_expire);

                spin_lock(&hash->uc_lock);
                remove_wait_queue(&entry->ue_waitq, &wait);
                if (UC_CACHE_IS_ACQUIRING(entry)) {
                        static unsigned long next;
                        /* we're interrupted or upcall failed in the middle */
                        if (time_after(jiffies, next)) {
                                CERROR("acquire timeout exceeded for key "LPU64
                                       "\n", entry->ue_key);
                                next = jiffies + 1800;
                        }
                        put_entry(entry);
                        GOTO(out, entry = ERR_PTR(-EIDRM));
                }
                /* fall through */
        }

        /* invalid means error, don't need to try again */
        if (UC_CACHE_IS_INVALID(entry)) {
                put_entry(entry);
                GOTO(out, entry = ERR_PTR(-EIDRM));
        }

        /* check expired
         * We can't refresh the existing one because some
         * memory might be shared by multiple processes.
         */
        if (check_unlink_entry(entry)) {
                /* if expired, try again. but if this entry is
                 * created by me but too quickly turn to expired
                 * without any error, should at least give a
                 * chance to use it once.
                 */
                if (entry != new) {
                        put_entry(entry);
                        spin_unlock(&hash->uc_lock);
                        new = NULL;
                        goto find_again;
                }
        }

        /* Now we know it's good */
out:
        spin_unlock(&hash->uc_lock);
        RETURN(entry);
}
EXPORT_SYMBOL(upcall_cache_get_entry);

void upcall_cache_put_entry(struct upcall_cache *hash,
                            struct upcall_cache_entry *entry)
{
        ENTRY;

        if (!entry) {
                EXIT;
                return;
        }

        LASSERT(atomic_read(&entry->ue_refcount) > 0);
        spin_lock(&hash->uc_lock);
        put_entry(entry);
        spin_unlock(&hash->uc_lock);
        EXIT;
}
EXPORT_SYMBOL(upcall_cache_put_entry);

int upcall_cache_downcall(struct upcall_cache *hash, __u32 err, __u64 key,
                          __u32 primary, __u32 ngroups, __u32 *groups)
{
        struct upcall_cache_entry *entry = NULL;
        struct list_head *head;
        int found = 0, rc = 0;
        ENTRY;

        LASSERT(hash);

        head = &hash->uc_hashtable[UC_CACHE_HASH_INDEX(key)];

        spin_lock(&hash->uc_lock);
        list_for_each_entry(entry, head, ue_hash) {
                if (entry->ue_key == key) {
                        found = 1;
                        get_entry(entry);
                        break;
                }
        }

        if (!found) {
                CDEBUG(D_OTHER, "%s: upcall for key "LPU64" not expected\n",
                       hash->uc_name, entry->ue_key);
                /* haven't found, it's possible */
                spin_unlock(&hash->uc_lock);
                RETURN(-EINVAL);
        }

        if (err) {
                CDEBUG(D_OTHER, "%s: upcall for key "LPU64" returned %d\n",
                       hash->uc_name, entry->ue_key, err);
                GOTO(out, rc = -EINVAL);
        }

        if (!UC_CACHE_IS_ACQUIRING(entry)) {
                CDEBUG(D_RPCTRACE,"%s: found uptodate entry %p (key "LPU64")\n",
                       hash->uc_name, entry, entry->ue_key);
                GOTO(out, rc = 0);
        }

        if (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry)) {
                CERROR("%s: found a stale entry %p (key "LPU64") in ioctl\n",
                       hash->uc_name, entry, entry->ue_key);
                GOTO(out, rc = -EINVAL);
        }

        spin_unlock(&hash->uc_lock);
        rc = entry_set_group_info(entry, primary, ngroups, groups);
        spin_lock(&hash->uc_lock);
        if (rc)
                GOTO(out, rc);

        entry->ue_expire = jiffies + hash->uc_entry_expire;
        UC_CACHE_SET_VALID(entry);
        CDEBUG(D_OTHER, "%s: created upcall cache entry %p for key "LPU64"\n",
               hash->uc_name, entry, entry->ue_key);
out:
        if (rc) {
                UC_CACHE_SET_INVALID(entry);
                list_del_init(&entry->ue_hash);
        }
        UC_CACHE_CLEAR_ACQUIRING(entry);
        spin_unlock(&hash->uc_lock);
        wake_up_all(&entry->ue_waitq);
        put_entry(entry);

        RETURN(rc);
}
EXPORT_SYMBOL(upcall_cache_downcall);

static void cache_flush(struct upcall_cache *hash, int force)
{
        struct upcall_cache_entry *entry, *next;
        int i;
        ENTRY;

        spin_lock(&hash->uc_lock);
        for (i = 0; i < UC_CACHE_HASH_SIZE; i++) {
                list_for_each_entry_safe(entry, next,
                                         &hash->uc_hashtable[i], ue_hash) {
                        if (!force && atomic_read(&entry->ue_refcount)) {
                                UC_CACHE_SET_EXPIRED(entry);
                                continue;
                        }
                        LASSERT(!atomic_read(&entry->ue_refcount));
                        free_entry(entry);
                }
        }
        spin_unlock(&hash->uc_lock);
        EXIT;
}

void upcall_cache_flush_idle(struct upcall_cache *cache)
{
        cache_flush(cache, 0);
}
EXPORT_SYMBOL(upcall_cache_flush_idle);

void upcall_cache_flush_all(struct upcall_cache *cache)
{
        cache_flush(cache, 1);
}
EXPORT_SYMBOL(upcall_cache_flush_all);

struct upcall_cache *upcall_cache_init(const char *name)
{
        struct upcall_cache *hash;
        int i;
        ENTRY;

        OBD_ALLOC(hash, sizeof(*hash));
        if (!hash)
                RETURN(ERR_PTR(-ENOMEM));

        spin_lock_init(&hash->uc_lock);
        for (i = 0; i < UC_CACHE_HASH_SIZE; i++)
                INIT_LIST_HEAD(&hash->uc_hashtable[i]);
        strncpy(hash->uc_name, name, sizeof(hash->uc_name) - 1);
        /* set default value, proc tunable */
        strcpy(hash->uc_upcall, "NONE");
        hash->uc_entry_expire = 10 * 60 * HZ;
        hash->uc_acquire_expire = 15 * HZ;

        RETURN(hash);
}
EXPORT_SYMBOL(upcall_cache_init);

void upcall_cache_cleanup(struct upcall_cache *hash)
{
        if (!hash)
                return;
        upcall_cache_flush_all(hash);
        OBD_FREE(hash, sizeof(*hash));
}
EXPORT_SYMBOL(upcall_cache_cleanup);