->d_parent changes are not protected by BKL anymore. Read access is safe
if at least one of the following is true:
* filesystem has no cross-directory rename()
- * dcache_lock is held
* we know that parent had been locked (e.g. we are looking at
->d_parent of ->lookup() argument).
* we are called from ->rename().
.d_hash() calling convention and locking rules are significantly
changed. Read updated documentation in Documentation/filesystems/vfs.txt (and
look at examples of other filesystems) for guidance.
+
+---
+[mandatory]
+ dcache_lock is gone, replaced by fine grained locks. See fs/dcache.c
+for details of what locks to replace dcache_lock with in order to protect
+particular things. Most of the time, a filesystem only needs ->d_lock, which
+protects *all* the dcache state of a given dentry.