diff options
Diffstat (limited to 'fs/fscache/cookie.c')
-rw-r--r-- | fs/fscache/cookie.c | 144 |
1 files changed, 95 insertions, 49 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 990535071a8a..0e91a3c9fdb2 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -95,6 +95,11 @@ struct fscache_cookie *__fscache_acquire_cookie( atomic_set(&cookie->usage, 1); atomic_set(&cookie->n_children, 0); + /* We keep the active count elevated until relinquishment to prevent an + * attempt to wake up every time the object operations queue quiesces. + */ + atomic_set(&cookie->n_active, 1); + atomic_inc(&parent->usage); atomic_inc(&parent->n_children); @@ -177,7 +182,6 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie) cookie->flags = (1 << FSCACHE_COOKIE_LOOKING_UP) | - (1 << FSCACHE_COOKIE_CREATING) | (1 << FSCACHE_COOKIE_NO_DATA_YET); /* ask the cache to allocate objects for this cookie and its parent @@ -205,7 +209,7 @@ static int fscache_acquire_non_index_cookie(struct fscache_cookie *cookie) /* initiate the process of looking up all the objects in the chain * (done by fscache_initialise_object()) */ - fscache_enqueue_object(object); + fscache_raise_event(object, FSCACHE_OBJECT_EV_NEW_CHILD); spin_unlock(&cookie->lock); @@ -237,13 +241,12 @@ static int fscache_alloc_object(struct fscache_cache *cache, struct fscache_cookie *cookie) { struct fscache_object *object; - struct hlist_node *_n; int ret; _enter("%p,%p{%s}", cache, cookie, cookie->def->name); spin_lock(&cookie->lock); - hlist_for_each_entry(object, _n, &cookie->backing_objects, + hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) { if (object->cache == cache) goto object_already_extant; @@ -286,7 +289,7 @@ static int fscache_alloc_object(struct fscache_cache *cache, object_already_extant: ret = -ENOBUFS; - if (object->state >= FSCACHE_OBJECT_DYING) { + if (fscache_object_is_dead(object)) { spin_unlock(&cookie->lock); goto error; } @@ -311,7 +314,6 @@ static int fscache_attach_object(struct fscache_cookie *cookie, { struct fscache_object *p; struct fscache_cache *cache = object->cache; - struct hlist_node *_n; int ret; _enter("{%s},{OBJ%x}", cookie->def->name, object->debug_id); @@ -321,9 +323,9 @@ static int fscache_attach_object(struct fscache_cookie *cookie, /* there may be multiple initial creations of this object, but we only * want one */ ret = -EEXIST; - hlist_for_each_entry(p, _n, &cookie->backing_objects, cookie_link) { + hlist_for_each_entry(p, &cookie->backing_objects, cookie_link) { if (p->cache == object->cache) { - if (p->state >= FSCACHE_OBJECT_DYING) + if (fscache_object_is_dying(p)) ret = -ENOBUFS; goto cant_attach_object; } @@ -331,10 +333,10 @@ static int fscache_attach_object(struct fscache_cookie *cookie, /* pin the parent object */ spin_lock_nested(&cookie->parent->lock, 1); - hlist_for_each_entry(p, _n, &cookie->parent->backing_objects, + hlist_for_each_entry(p, &cookie->parent->backing_objects, cookie_link) { if (p->cache == object->cache) { - if (p->state >= FSCACHE_OBJECT_DYING) { + if (fscache_object_is_dying(p)) { ret = -ENOBUFS; spin_unlock(&cookie->parent->lock); goto cant_attach_object; @@ -370,12 +372,71 @@ cant_attach_object: } /* + * Invalidate an object. Callable with spinlocks held. + */ +void __fscache_invalidate(struct fscache_cookie *cookie) +{ + struct fscache_object *object; + + _enter("{%s}", cookie->def->name); + + fscache_stat(&fscache_n_invalidates); + + /* Only permit invalidation of data files. Invalidating an index will + * require the caller to release all its attachments to the tree rooted + * there, and if it's doing that, it may as well just retire the + * cookie. + */ + ASSERTCMP(cookie->def->type, ==, FSCACHE_COOKIE_TYPE_DATAFILE); + + /* We will be updating the cookie too. */ + BUG_ON(!cookie->def->get_aux); + + /* If there's an object, we tell the object state machine to handle the + * invalidation on our behalf, otherwise there's nothing to do. + */ + if (!hlist_empty(&cookie->backing_objects)) { + spin_lock(&cookie->lock); + + if (!hlist_empty(&cookie->backing_objects) && + !test_and_set_bit(FSCACHE_COOKIE_INVALIDATING, + &cookie->flags)) { + object = hlist_entry(cookie->backing_objects.first, + struct fscache_object, + cookie_link); + if (fscache_object_is_live(object)) + fscache_raise_event( + object, FSCACHE_OBJECT_EV_INVALIDATE); + } + + spin_unlock(&cookie->lock); + } + + _leave(""); +} +EXPORT_SYMBOL(__fscache_invalidate); + +/* + * Wait for object invalidation to complete. + */ +void __fscache_wait_on_invalidate(struct fscache_cookie *cookie) +{ + _enter("%p", cookie); + + wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING, + fscache_wait_bit_interruptible, + TASK_UNINTERRUPTIBLE); + + _leave(""); +} +EXPORT_SYMBOL(__fscache_wait_on_invalidate); + +/* * update the index entries backing a cookie */ void __fscache_update_cookie(struct fscache_cookie *cookie) { struct fscache_object *object; - struct hlist_node *_p; fscache_stat(&fscache_n_updates); @@ -392,7 +453,7 @@ void __fscache_update_cookie(struct fscache_cookie *cookie) spin_lock(&cookie->lock); /* update the index entry on disk in each cache backing this cookie */ - hlist_for_each_entry(object, _p, + hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) { fscache_raise_event(object, FSCACHE_OBJECT_EV_UPDATE); } @@ -410,9 +471,7 @@ EXPORT_SYMBOL(__fscache_update_cookie); */ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) { - struct fscache_cache *cache; struct fscache_object *object; - unsigned long event; fscache_stat(&fscache_n_relinquishes); if (retire) @@ -424,8 +483,11 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) return; } - _enter("%p{%s,%p},%d", - cookie, cookie->def->name, cookie->netfs_data, retire); + _enter("%p{%s,%p,%d},%d", + cookie, cookie->def->name, cookie->netfs_data, + atomic_read(&cookie->n_active), retire); + + ASSERTCMP(atomic_read(&cookie->n_active), >, 0); if (atomic_read(&cookie->n_children) != 0) { printk(KERN_ERR "FS-Cache: Cookie '%s' still has children\n", @@ -433,44 +495,28 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) BUG(); } - /* wait for the cookie to finish being instantiated (or to fail) */ - if (test_bit(FSCACHE_COOKIE_CREATING, &cookie->flags)) { - fscache_stat(&fscache_n_relinquishes_waitcrt); - wait_on_bit(&cookie->flags, FSCACHE_COOKIE_CREATING, - fscache_wait_bit, TASK_UNINTERRUPTIBLE); - } - - event = retire ? FSCACHE_OBJECT_EV_RETIRE : FSCACHE_OBJECT_EV_RELEASE; + /* No further netfs-accessing operations on this cookie permitted */ + set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags); + if (retire) + set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags); spin_lock(&cookie->lock); - - /* break links with all the active objects */ - while (!hlist_empty(&cookie->backing_objects)) { - object = hlist_entry(cookie->backing_objects.first, - struct fscache_object, - cookie_link); - - _debug("RELEASE OBJ%x", object->debug_id); - - /* detach each cache object from the object cookie */ - spin_lock(&object->lock); - hlist_del_init(&object->cookie_link); - - cache = object->cache; - object->cookie = NULL; - fscache_raise_event(object, event); - spin_unlock(&object->lock); - - if (atomic_dec_and_test(&cookie->usage)) - /* the cookie refcount shouldn't be reduced to 0 yet */ - BUG(); + hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) { + fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL); } + spin_unlock(&cookie->lock); + + /* Wait for cessation of activity requiring access to the netfs (when + * n_active reaches 0). + */ + if (!atomic_dec_and_test(&cookie->n_active)) + wait_on_atomic_t(&cookie->n_active, fscache_wait_atomic_t, + TASK_UNINTERRUPTIBLE); - /* detach pointers back to the netfs */ + /* Clear pointers back to the netfs */ cookie->netfs_data = NULL; cookie->def = NULL; - - spin_unlock(&cookie->lock); + BUG_ON(cookie->stores.rnode); if (cookie->parent) { ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0); @@ -478,7 +524,7 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, int retire) atomic_dec(&cookie->parent->n_children); } - /* finally dispose of the cookie */ + /* Dispose of the netfs's link to the cookie */ ASSERTCMP(atomic_read(&cookie->usage), >, 0); fscache_cookie_put(cookie); |