fold _d_rehash() and __d_rehash() together

The only place where we feed to __d_rehash() something other than
d_hash(dentry->d_name.hash) is __d_move(), where we give it d_hash
of another dentry.  Postpone rehashing until we'd switched the
names and we are rid of that exception, along with the need to
keep _d_rehash() and __d_rehash() separate.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 11 insertions, 23 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 6a629f50c3cf..d9450bd496ac 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2339,19 +2339,15 @@ again:
 }
 EXPORT_SYMBOL(d_delete);
 
-static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b)
+static void __d_rehash(struct dentry *entry)
 {
+        struct hlist_bl_head *b = d_hash(entry->d_name.hash);
         BUG_ON(!d_unhashed(entry));
         hlist_bl_lock(b);
         hlist_bl_add_head_rcu(&entry->d_hash, b);
         hlist_bl_unlock(b);
 }
 
-static void _d_rehash(struct dentry * entry)
-{
-        __d_rehash(entry, d_hash(entry->d_name.hash));
-}
-
 /**
  * d_rehash     - add an entry back to the hash
  * @entry: dentry to add to the hash
@@ -2362,7 +2358,7 @@ static void _d_rehash(struct dentry * entry)
 void d_rehash(struct dentry * entry)
 {
         spin_lock(&entry->d_lock);
-        _d_rehash(entry);
+        __d_rehash(entry);
         spin_unlock(&entry->d_lock);
 }
 EXPORT_SYMBOL(d_rehash);
@@ -2536,7 +2532,7 @@ static inline void __d_add(struct dentry *dentry, struct inode *inode)
                 raw_write_seqcount_end(&dentry->d_seq);
                 fsnotify_update_flags(dentry);
         }
-        _d_rehash(dentry);
+        __d_rehash(dentry);
         if (dir)
                 end_dir_add(dir, n);
         spin_unlock(&dentry->d_lock);
@@ -2598,7 +2594,7 @@ struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode)
                         alias = NULL;
                 } else {
                         __dget_dlock(alias);
-                        _d_rehash(alias);
+                        __d_rehash(alias);
                         spin_unlock(&alias->d_lock);
                 }
                 spin_unlock(&inode->i_lock);
@@ -2782,23 +2778,10 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
         write_seqcount_begin(&dentry->d_seq);
         write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED);
 
+        /* unhash both */
         /* __d_drop does write_seqcount_barrier, but they're OK to nest. */
-
-        /*
-         * Move the dentry to the target hash queue. Don't bother checking
-         * for the same hash queue because of how unlikely it is.
-         */
         __d_drop(dentry);
-        __d_rehash(dentry, d_hash(target->d_name.hash));
-
-        /*
-         * Unhash the target (d_delete() is not usable here).  If exchanging
-         * the two dentries, then rehash onto the other's hash queue.
-         */
         __d_drop(target);
-        if (exchange) {
-                __d_rehash(target, d_hash(dentry->d_name.hash));
-        }
 
         /* Switch the names.. */
         if (exchange)
@@ -2806,6 +2789,11 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
         else
                 copy_name(dentry, target);
 
+        /* rehash in new place(s) */
+        __d_rehash(dentry);
+        if (exchange)
+                __d_rehash(target);
+
         /* ... and switch them in the tree */
         if (IS_ROOT(dentry)) {
                 /* splicing a tree */