Merge branch 'dcache-cleanup'

* dcache-cleanup:
  vfs: get rid of insane dentry hashing rules

1 files changed, 16 insertions, 26 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 7108c15685dd..d600a0af3b2e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -164,8 +164,8 @@ static void d_free(struct dentry *dentry)
         if (dentry->d_op && dentry->d_op->d_release)
                 dentry->d_op->d_release(dentry);
 
-        /* if dentry was never inserted into hash, immediate free is OK */
-        if (hlist_bl_unhashed(&dentry->d_hash))
+        /* if dentry was never visible to RCU, immediate free is OK */
+        if (!(dentry->d_flags & DCACHE_RCUACCESS))
                 __d_free(&dentry->d_u.d_rcu);
         else
                 call_rcu(&dentry->d_u.d_rcu, __d_free);
@@ -327,28 +327,19 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
  */
 void __d_drop(struct dentry *dentry)
 {
-        if (!(dentry->d_flags & DCACHE_UNHASHED)) {
+        if (!d_unhashed(dentry)) {
                 struct hlist_bl_head *b;
-                if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) {
+                if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
                         b = &dentry->d_sb->s_anon;
-                        spin_lock_bucket(b);
-                        dentry->d_flags |= DCACHE_UNHASHED;
-                        hlist_bl_del_init(&dentry->d_hash);
-                        spin_unlock_bucket(b);
-                } else {
-                        struct hlist_bl_head *b;
+                else
                         b = d_hash(dentry->d_parent, dentry->d_name.hash);
-                        spin_lock_bucket(b);
-                        /*
-                         * We may not actually need to put DCACHE_UNHASHED
-                         * manipulations under the hash lock, but follow
-                         * the principle of least surprise.
-                         */
-                        dentry->d_flags |= DCACHE_UNHASHED;
-                        hlist_bl_del_rcu(&dentry->d_hash);
-                        spin_unlock_bucket(b);
-                        dentry_rcuwalk_barrier(dentry);
-                }
+
+                spin_lock_bucket(b);
+                __hlist_bl_del(&dentry->d_hash);
+                dentry->d_hash.pprev = NULL;
+                spin_unlock_bucket(b);
+
+                dentry_rcuwalk_barrier(dentry);
         }
 }
 EXPORT_SYMBOL(__d_drop);
@@ -1301,7 +1292,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
         dname[name->len] = 0;
 
         dentry->d_count = 1;
-        dentry->d_flags = DCACHE_UNHASHED;
+        dentry->d_flags = 0;
         spin_lock_init(&dentry->d_lock);
         seqcount_init(&dentry->d_seq);
         dentry->d_inode = NULL;
@@ -1603,10 +1594,9 @@ struct dentry *d_obtain_alias(struct inode *inode)
         tmp->d_inode = inode;
         tmp->d_flags |= DCACHE_DISCONNECTED;
         list_add(&tmp->d_alias, &inode->i_dentry);
-        bit_spin_lock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
-        tmp->d_flags &= ~DCACHE_UNHASHED;
+        spin_lock_bucket(&tmp->d_sb->s_anon);
         hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
-        __bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
+        spin_unlock_bucket(&tmp->d_sb->s_anon);
         spin_unlock(&tmp->d_lock);
         spin_unlock(&inode->i_lock);
         security_d_instantiate(tmp, inode);
@@ -2087,7 +2077,7 @@ static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b)
 {
         BUG_ON(!d_unhashed(entry));
         spin_lock_bucket(b);
-        entry->d_flags &= ~DCACHE_UNHASHED;
+        entry->d_flags |= DCACHE_RCUACCESS;
         hlist_bl_add_head_rcu(&entry->d_hash, b);
         spin_unlock_bucket(b);
 }