fs: rcu-walk aware d_revalidate method

Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

1 files changed, 9 insertions, 9 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index bdad6414dfa0..e90ffe61eb65 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -9,7 +9,7 @@ be able to use diff(1).
 
 --------------------------- dentry_operations --------------------------
 prototypes:
-        int (*d_revalidate)(struct dentry *, int);
+        int (*d_revalidate)(struct dentry *, struct nameidata *);
         int (*d_hash)(const struct dentry *, const struct inode *,
                         struct qstr *);
         int (*d_compare)(const struct dentry *, const struct inode *,
@@ -21,14 +21,14 @@ prototypes:
         char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
 
 locking rules:
-                rename_lock     ->d_lock        may block
-d_revalidate:   no              no              yes
-d_hash          no              no              no
-d_compare:      yes             no              no
-d_delete:       no              yes             no
-d_release:      no              no              yes
-d_iput:         no              no              yes
-d_dname:        no              no              no
+                rename_lock     ->d_lock        may block       rcu-walk
+d_revalidate:   no              no              yes (ref-walk)  maybe
+d_hash          no              no              no              maybe
+d_compare:      yes             no              no              maybe
+d_delete:       no              yes             no              no
+d_release:      no              no              yes             no
+d_iput:         no              no              yes             no
+d_dname:        no              no              no              no
 
 --------------------------- inode_operations --------------------------- 
 prototypes: