fs: change d_hash for rcu-walk

Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.

For in-tree filesystems, this is just a mechanical change.

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

1 files changed, 6 insertions, 2 deletions

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 250681b8c7cc..69b10ff5ec81 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -847,7 +847,8 @@ defined:
 
 struct dentry_operations {
         int (*d_revalidate)(struct dentry *, struct nameidata *);
-        int (*d_hash)(struct dentry *, struct qstr *);
+        int (*d_hash)(const struct dentry *, const struct inode *,
+                        struct qstr *);
         int (*d_compare)(const struct dentry *, const struct inode *,
                         const struct dentry *, const struct inode *,
                         unsigned int, const char *, const struct qstr *);
@@ -864,7 +865,10 @@ struct dentry_operations {
 
   d_hash: called when the VFS adds a dentry to the hash table. The first
         dentry passed to d_hash is the parent directory that the name is
-        to be hashed into.
+        to be hashed into. The inode is the dentry's inode.
+
+        Same locking and synchronisation rules as d_compare regarding
+        what is safe to dereference etc.
 
   d_compare: called to compare a dentry name with a given name. The first
         dentry is the parent of the dentry to be compared, the second is