AFS fixes

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Merge tag 'afs-fixes-20190117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:
 "Here's a set of fixes for AFS:

   - Use struct_size() for kzalloc() size calculation.

   - When calling YFS.CreateFile rather than AFS.CreateFile, it is
     possible to create a file with a file lock already held. The
     default value indicating no lock required is actually -1, not 0.

   - Fix an oops in inode/vnode validation if the target inode doesn't
     have a server interest assigned (ie. a server that will notify us
     of changes by third parties).

   - Fix refcounting of keys in file locking.

   - Fix a race in refcounting asynchronous operations in the event of
     an error during request transmission. The provision of a dedicated
     function to get an extra ref on a call is split into a separate
     commit"

* tag 'afs-fixes-20190117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix race in async call refcounting
  afs: Provide a function to get a ref on a call
  afs: Fix key refcounting in file locking code
  afs: Don't set vnode->cb_s_break in afs_validate()
  afs: Set correct lock type for the yfs CreateFile
  afs: Use struct_size() in kzalloc()

fs/afs/flock.c

@@ -208,7 +208,7 @@ again:
 		/* The new front of the queue now owns the state variables. */
 		next = list_entry(vnode->pending_locks.next,
 				  struct file_lock, fl_u.afs.link);
-		vnode->lock_key = afs_file_key(next->fl_file);
+		vnode->lock_key = key_get(afs_file_key(next->fl_file));
 		vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 		vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;
 		goto again;
@@ -413,7 +413,7 @@ static void afs_dequeue_lock(struct afs_vnode *vnode, struct file_lock *fl)
 	/* The new front of the queue now owns the state variables. */
 	next = list_entry(vnode->pending_locks.next,
 			  struct file_lock, fl_u.afs.link);
-	vnode->lock_key = afs_file_key(next->fl_file);
+	vnode->lock_key = key_get(afs_file_key(next->fl_file));
 	vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
 	vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB;
 	afs_lock_may_be_available(vnode);

fs/afs/inode.c

@@ -414,7 +414,6 @@ int afs_validate(struct afs_vnode *vnode, struct key *key)
 	} else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 		valid = true;
 	} else {
-		vnode->cb_s_break = vnode->cb_interest->server->cb_s_break;
 		vnode->cb_v_break = vnode->volume->cb_v_break;
 		valid = false;
 	}
@@ -546,6 +545,8 @@ void afs_evict_inode(struct inode *inode)
 #endif
 
 	afs_put_permits(rcu_access_pointer(vnode->permit_cache));
+	key_put(vnode->lock_key);
+	vnode->lock_key = NULL;
 	_leave("");
 }
 

fs/afs/protocol_yfs.h

@@ -161,3 +161,14 @@ struct yfs_xdr_YFSStoreVolumeStatus {
 	struct yfs_xdr_u64	max_quota;
 	struct yfs_xdr_u64	file_quota;
 } __packed;
+
+enum yfs_lock_type {
+	yfs_LockNone		= -1,
+	yfs_LockRead		= 0,
+	yfs_LockWrite		= 1,
+	yfs_LockExtend		= 2,
+	yfs_LockRelease		= 3,
+	yfs_LockMandatoryRead	= 0x100,
+	yfs_LockMandatoryWrite	= 0x101,
+	yfs_LockMandatoryExtend	= 0x102,
+};

fs/afs/rxrpc.c

@@ -23,6 +23,7 @@ struct workqueue_struct *afs_async_calls;
 static void afs_wake_up_call_waiter(struct sock *, struct rxrpc_call *, unsigned long);
 static long afs_wait_for_call_to_complete(struct afs_call *, struct afs_addr_cursor *);
 static void afs_wake_up_async_call(struct sock *, struct rxrpc_call *, unsigned long);
+static void afs_delete_async_call(struct work_struct *);
 static void afs_process_async_call(struct work_struct *);
 static void afs_rx_new_call(struct sock *, struct rxrpc_call *, unsigned long);
 static void afs_rx_discard_new_call(struct rxrpc_call *, unsigned long);
@@ -203,20 +204,26 @@ void afs_put_call(struct afs_call *call)
 	}
 }
 
+static struct afs_call *afs_get_call(struct afs_call *call,
+				     enum afs_call_trace why)
+{
+	int u = atomic_inc_return(&call->usage);
+
+	trace_afs_call(call, why, u,
+		       atomic_read(&call->net->nr_outstanding_calls),
+		       __builtin_return_address(0));
+	return call;
+}
+
 /*
  * Queue the call for actual work.
  */
 static void afs_queue_call_work(struct afs_call *call)
 {
 	if (call->type->work) {
-		int u = atomic_inc_return(&call->usage);
-
-		trace_afs_call(call, afs_call_trace_work, u,
-			       atomic_read(&call->net->nr_outstanding_calls),
-			       __builtin_return_address(0));
-
 		INIT_WORK(&call->work, call->type->work);
 
+		afs_get_call(call, afs_call_trace_work);
 		if (!queue_work(afs_wq, &call->work))
 			afs_put_call(call);
 	}
@@ -398,6 +405,12 @@ long afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call,
 		}
 	}
 
+	/* If the call is going to be asynchronous, we need an extra ref for
+	 * the call to hold itself so the caller need not hang on to its ref.
+	 */
+	if (call->async)
+		afs_get_call(call, afs_call_trace_get);
+
 	/* create a call */
 	rxcall = rxrpc_kernel_begin_call(call->net->socket, srx, call->key,
 					 (unsigned long)call,
@@ -438,15 +451,17 @@ long afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call,
 			goto error_do_abort;
 	}
 
-	/* at this point, an async call may no longer exist as it may have
-	 * already completed */
-	if (call->async)
+	/* Note that at this point, we may have received the reply or an abort
+	 * - and an asynchronous call may already have completed.
+	 */
+	if (call->async) {
+		afs_put_call(call);
 		return -EINPROGRESS;
+	}
 
 	return afs_wait_for_call_to_complete(call, ac);
 
 error_do_abort:
-	call->state = AFS_CALL_COMPLETE;
 	if (ret != -ECONNABORTED) {
 		rxrpc_kernel_abort_call(call->net->socket, rxcall,
 					RX_USER_ABORT, ret, "KSD");
@@ -463,8 +478,24 @@ error_do_abort:
 error_kill_call:
 	if (call->type->done)
 		call->type->done(call);
-	afs_put_call(call);
+
+	/* We need to dispose of the extra ref we grabbed for an async call.
+	 * The call, however, might be queued on afs_async_calls and we need to
+	 * make sure we don't get any more notifications that might requeue it.
+	 */
+	if (call->rxcall) {
+		rxrpc_kernel_end_call(call->net->socket, call->rxcall);
+		call->rxcall = NULL;
+	}
+	if (call->async) {
+		if (cancel_work_sync(&call->async_work))
+			afs_put_call(call);
+		afs_put_call(call);
+	}
+
 	ac->error = ret;
+	call->state = AFS_CALL_COMPLETE;
+	afs_put_call(call);
 	_leave(" = %d", ret);
 	return ret;
 }

fs/afs/server_list.c

@@ -42,9 +42,7 @@ struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
 		if (vldb->fs_mask[i] & type_mask)
 			nr_servers++;
 
-	slist = kzalloc(sizeof(struct afs_server_list) +
-			sizeof(struct afs_server_entry) * nr_servers,
-			GFP_KERNEL);
+	slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL);
 	if (!slist)
 		goto error;
 

fs/afs/yfsclient.c

@@ -803,7 +803,7 @@ int yfs_fs_create_file(struct afs_fs_cursor *fc,
 	bp = xdr_encode_YFSFid(bp, &vnode->fid);
 	bp = xdr_encode_string(bp, name, namesz);
 	bp = xdr_encode_YFSStoreStatus_mode(bp, mode);
-	bp = xdr_encode_u32(bp, 0); /* ViceLockType */
+	bp = xdr_encode_u32(bp, yfs_LockNone); /* ViceLockType */
 	yfs_check_req(call, bp);
 
 	afs_use_fs_server(call, fc->cbi);

include/trace/events/afs.h

@@ -25,6 +25,7 @@
 enum afs_call_trace {
 	afs_call_trace_alloc,
 	afs_call_trace_free,
+	afs_call_trace_get,
 	afs_call_trace_put,
 	afs_call_trace_wake,
 	afs_call_trace_work,
@@ -159,6 +160,7 @@ enum afs_file_error {
 #define afs_call_traces \
 	EM(afs_call_trace_alloc,		"ALLOC") \
 	EM(afs_call_trace_free,			"FREE ") \
+	EM(afs_call_trace_get,			"GET  ") \
 	EM(afs_call_trace_put,			"PUT  ") \
 	EM(afs_call_trace_wake,			"WAKE ") \
 	E_(afs_call_trace_work,			"WORK ")