Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull namei updates from Al Viro:
 "Most of that pile is LOOKUP_CACHED series; the rest is a couple of
  misc cleanups in the general area...

  There's a minor bisect hazard in the end of series, and normally I
  would've just folded the fix into the previous commit, but this branch
  is shared with Jens' tree, with stuff on top of it in there, so that
  would've required rebases outside of vfs.git"

* 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix handling of nd->depth on LOOKUP_CACHED failures in try_to_unlazy*
  fs: expose LOOKUP_CACHED through openat2() RESOLVE_CACHED
  fs: add support for LOOKUP_CACHED
  saner calling conventions for unlazy_child()
  fs: make unlazy_walk() error handling consistent
  fs/namei.c: Remove unlikely of status being -ECHILD in lookup_fast()
  do_tmpfile(): don't mess with finish_open()

include/uapi/linux/openat2.h

@@ -35,5 +35,9 @@ struct open_how {
 #define RESOLVE_IN_ROOT		0x10 /* Make all jumps to "/" and ".."
 					be scoped inside the dirfd
 					(similar to chroot(2)). */
+#define RESOLVE_CACHED		0x20 /* Only complete if resolution can be
+					completed through cached lookup. May
+					return -EAGAIN if that's not
+					possible. */
 
 #endif /* _UAPI_LINUX_OPENAT2_H */