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authorDavid Howells <dhowells@redhat.com>2012-12-21 01:52:36 +0400
committerDavid Howells <dhowells@redhat.com>2012-12-21 02:04:07 +0400
commitef778e7ae67cd426c30cad43378b908f5eb0bad5 (patch)
tree4893f19487cb99e8ec0eb835ec4391d952641a9c /fs/fscache/cookie.c
parent9f10523f891928330b7529da54c1a3cc65180b1a (diff)
downloadlinux-ef778e7ae67cd426c30cad43378b908f5eb0bad5.tar.xz
FS-Cache: Provide proper invalidation
Provide a proper invalidation method rather than relying on the netfs retiring the cookie it has and getting a new one. The problem with this is that isn't easy for the netfs to make sure that it has completed/cancelled all its outstanding storage and retrieval operations on the cookie it is retiring. Instead, have the cache provide an invalidation method that will cancel or wait for all currently outstanding operations before invalidating the cache, and will cause new operations to queue up behind that. Whilst invalidation is in progress, some requests will be rejected until the cache can stack a barrier on the operation queue to cause new operations to be deferred behind it. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/fscache/cookie.c')
-rw-r--r--fs/fscache/cookie.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 66be9eccede0..8dcb114758e3 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -370,6 +370,66 @@ 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 (object->state < FSCACHE_OBJECT_DYING)
+ 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)