Merge tag 'fscache-next-20180406' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fscache updates from David Howells:
 "Three patches that fix some of AFS's usage of fscache:

   (1) Need to invalidate the cache if a foreign data change is detected
       on the server.

   (2) Move the vnode ID uniquifier (equivalent to i_generation) from
       the auxiliary data to the index key to prevent a race between
       file delete and a subsequent file create seeing the same index
       key.

   (3) Need to retire cookies that correspond to files that we think got
       deleted on the server.

  Four patches to fix some things in fscache and cachefiles:

   (4) Fix a couple of checker warnings.

   (5) Correctly indicate to the end-of-operation callback whether an
       operation completed or was cancelled.

   (6) Add a check for multiple cookie relinquishment.

   (7) Fix a path through the asynchronous write that doesn't wake up a
       waiter for a page if the cache decides not to write that page,
       but discards it instead.

  A couple of patches to add tracepoints to fscache and cachefiles:

   (8) Add tracepoints for cookie operators, object state machine
       execution, cachefiles object management and cachefiles VFS
       operations.

   (9) Add tracepoints for fscache operation management and page
       wrangling.

  And then three development patches:

  (10) Attach the index key and auxiliary data to the cookie, pass this
       information through various fscache-netfs API functions and get
       rid of the callbacks to the netfs to get it.

       This means that the cache can get at this information, even if
       the netfs goes away. It also means that the cache can be lazy in
       updating the coherency data.

  (11) Pass the object data size through various fscache-netfs API
       rather than calling back to the netfs for it, and store the value
       in the object.

       This makes it easier to correctly resize the object, as the size
       is updated on writes to the cache, rather than calling back out
       to the netfs.

  (12) Maintain a catalogue of allocated cookies. This makes it possible
       to catch cookie collision up front rather than down in the bowels
       of the cache being run from a service thread from the object
       state machine.

       This will also make it possible in the future to reconnect to a
       cookie that's not gone dead yet because it's waiting for
       finalisation of the storage and also make it possible to bring
       cookies online if the cache is added after the cookie has been
       obtained"

* tag 'fscache-next-20180406' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  fscache: Maintain a catalogue of allocated cookies
  fscache: Pass object size in rather than calling back for it
  fscache: Attach the index key and aux data to the cookie
  fscache: Add more tracepoints
  fscache: Add tracepoints
  fscache: Fix hanging wait on page discarded by writeback
  fscache: Detect multiple relinquishment of a cookie
  fscache: Pass the correct cancelled indications to fscache_op_complete()
  fscache, cachefiles: Fix checker warnings
  afs: Be more aggressive in retiring cached vnodes
  afs: Use the vnode ID uniquifier in the cache key not the aux data
  afs: Invalidate cache on server data change

1 files changed, 40 insertions, 21 deletions

diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index e7f16a77a22a..222bc5d8b62c 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -32,7 +32,7 @@ static struct fscache_object *cachefiles_alloc_object(
 	struct cachefiles_cache *cache;
 	struct cachefiles_xattr *auxdata;
 	unsigned keylen, auxlen;
-	void *buffer;
+	void *buffer, *p;
 	char *key;
 
 	cache = container_of(_cache, struct cachefiles_cache, cache);
@@ -65,8 +65,12 @@ static struct fscache_object *cachefiles_alloc_object(
 	if (!buffer)
 		goto nomem_buffer;
 
-	keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
-	ASSERTCMP(keylen, <, 512);
+	keylen = cookie->key_len;
+	if (keylen <= sizeof(cookie->inline_key))
+		p = cookie->inline_key;
+	else
+		p = cookie->key;
+	memcpy(buffer + 2, p, keylen);
 
 	*(uint16_t *)buffer = keylen;
 	((char *)buffer)[keylen + 2] = 0;
@@ -80,15 +84,17 @@ static struct fscache_object *cachefiles_alloc_object(
 
 	/* get hold of the auxiliary data and prepend the object type */
 	auxdata = buffer;
-	auxlen = 0;
-	if (cookie->def->get_aux) {
-		auxlen = cookie->def->get_aux(cookie->netfs_data,
-					      auxdata->data, 511);
-		ASSERTCMP(auxlen, <, 511);
+	auxlen = cookie->aux_len;
+	if (auxlen) {
+		if (auxlen <= sizeof(cookie->inline_aux))
+			p = cookie->inline_aux;
+		else
+			p = cookie->aux;
+		memcpy(auxdata->data, p, auxlen);
 	}
 
 	auxdata->len = auxlen + 1;
-	auxdata->type = cookie->def->type;
+	auxdata->type = cookie->type;
 
 	lookup_data->auxdata = auxdata;
 	lookup_data->key = key;
@@ -177,10 +183,12 @@ static void cachefiles_lookup_complete(struct fscache_object *_object)
  * increment the usage count on an inode object (may fail if unmounting)
  */
 static
-struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
+struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
+					      enum fscache_obj_ref_trace why)
 {
 	struct cachefiles_object *object =
 		container_of(_object, struct cachefiles_object, fscache);
+	int u;
 
 	_enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
 
@@ -188,7 +196,9 @@ struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
 	ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
 #endif
 
-	atomic_inc(&object->usage);
+	u = atomic_inc_return(&object->usage);
+	trace_cachefiles_ref(object, _object->cookie,
+			     (enum cachefiles_obj_ref_trace)why, u);
 	return &object->fscache;
 }
 
@@ -202,6 +212,7 @@ static void cachefiles_update_object(struct fscache_object *_object)
 	struct cachefiles_cache *cache;
 	struct fscache_cookie *cookie;
 	const struct cred *saved_cred;
+	const void *aux;
 	unsigned auxlen;
 
 	_enter("{OBJ%x}", _object->debug_id);
@@ -216,26 +227,29 @@ static void cachefiles_update_object(struct fscache_object *_object)
 	}
 
 	cookie = object->fscache.cookie;
+	auxlen = cookie->aux_len;
 
-	if (!cookie->def->get_aux) {
+	if (!auxlen) {
 		fscache_unuse_cookie(_object);
 		_leave(" [no aux]");
 		return;
 	}
 
-	auxdata = kmalloc(2 + 512 + 3, cachefiles_gfp);
+	auxdata = kmalloc(2 + auxlen + 3, cachefiles_gfp);
 	if (!auxdata) {
 		fscache_unuse_cookie(_object);
 		_leave(" [nomem]");
 		return;
 	}
 
-	auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
+	aux = (auxlen <= sizeof(cookie->inline_aux)) ?
+		cookie->inline_aux : cookie->aux;
+
+	memcpy(auxdata->data, aux, auxlen);
 	fscache_unuse_cookie(_object);
-	ASSERTCMP(auxlen, <, 511);
 
 	auxdata->len = auxlen + 1;
-	auxdata->type = cookie->def->type;
+	auxdata->type = cookie->type;
 
 	cachefiles_begin_secure(cache, &saved_cred);
 	cachefiles_update_object_xattr(object, auxdata);
@@ -309,10 +323,12 @@ static void cachefiles_drop_object(struct fscache_object *_object)
 /*
  * dispose of a reference to an object
  */
-static void cachefiles_put_object(struct fscache_object *_object)
+static void cachefiles_put_object(struct fscache_object *_object,
+				  enum fscache_obj_ref_trace why)
 {
 	struct cachefiles_object *object;
 	struct fscache_cache *cache;
+	int u;
 
 	ASSERT(_object);
 
@@ -328,7 +344,11 @@ static void cachefiles_put_object(struct fscache_object *_object)
 	ASSERTIFCMP(object->fscache.parent,
 		    object->fscache.parent->n_children, >, 0);
 
-	if (atomic_dec_and_test(&object->usage)) {
+	u = atomic_dec_return(&object->usage);
+	trace_cachefiles_ref(object, _object->cookie,
+			     (enum cachefiles_obj_ref_trace)why, u);
+	ASSERTCMP(u, !=, -1);
+	if (u == 0) {
 		_debug("- kill object OBJ%x", object->fscache.debug_id);
 
 		ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
@@ -421,7 +441,7 @@ static int cachefiles_attr_changed(struct fscache_object *_object)
 	loff_t oi_size;
 	int ret;
 
-	_object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
+	ni_size = _object->store_limit_l;
 
 	_enter("{OBJ%x},[%llu]",
 	       _object->debug_id, (unsigned long long) ni_size);
@@ -493,8 +513,7 @@ static void cachefiles_invalidate_object(struct fscache_operation *op)
 	cache = container_of(object->fscache.cache,
 			     struct cachefiles_cache, cache);
 
-	op->object->cookie->def->get_attr(op->object->cookie->netfs_data,
-					  &ni_size);
+	ni_size = op->object->store_limit_l;
 
 	_enter("{OBJ%x},[%llu]",
 	       op->object->debug_id, (unsigned long long)ni_size);