AFS: AFS fixups

Make some miscellaneous changes to the AFS filesystem:

 (1) Assert RCU barriers on module exit to make sure RCU has finished with
     callbacks in this module.

 (2) Correctly handle the AFS server returning a zero-length read.

 (3) Split out data zapping calls into one function (afs_zap_data).

 (4) Rename some afs_file_*() functions to afs_*() where they apply to
     non-regular files too.

 (5) Be consistent about the presentation of volume ID:vnode ID in debugging
     output.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/afs/server.c b/fs/afs/server.c
index 96bb23b..231ae41 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -252,6 +252,9 @@
 {
 	_enter("%p", server);
 
+	ASSERTIF(server->cb_break_head != server->cb_break_tail,
+		 delayed_work_pending(&server->cb_break_work));
+
 	ASSERTCMP(server->fs_vnodes.rb_node, ==, NULL);
 	ASSERTCMP(server->cb_promises.rb_node, ==, NULL);
 	ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail);