1 files changed, 33 insertions, 56 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index ad25c4cec7d5..22a0ef41bad1 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -99,12 +99,9 @@ static struct kmem_cache *dentry_cache __read_mostly;
 static unsigned int d_hash_mask __read_mostly;
 static unsigned int d_hash_shift __read_mostly;
 
-struct dcache_hash_bucket {
-        struct hlist_bl_head head;
-};
-static struct dcache_hash_bucket *dentry_hashtable __read_mostly;
+static struct hlist_bl_head *dentry_hashtable __read_mostly;
 
-static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
+static inline struct hlist_bl_head *d_hash(struct dentry *parent,
                                         unsigned long hash)
 {
         hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
@@ -112,16 +109,6 @@ static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
         return dentry_hashtable + (hash & D_HASHMASK);
 }
 
-static inline void spin_lock_bucket(struct dcache_hash_bucket *b)
-{
-        bit_spin_lock(0, (unsigned long *)&b->head.first);
-}
-
-static inline void spin_unlock_bucket(struct dcache_hash_bucket *b)
-{
-        __bit_spin_unlock(0, (unsigned long *)&b->head.first);
-}
-
 /* Statistics gathering. */
 struct dentry_stat_t dentry_stat = {
         .age_limit = 45,
@@ -167,8 +154,8 @@ 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);
@@ -330,28 +317,19 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
  */
 void __d_drop(struct dentry *dentry)
 {
-        if (!(dentry->d_flags & DCACHE_UNHASHED)) {
-                if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) {
-                        bit_spin_lock(0,
-                                (unsigned long *)&dentry->d_sb->s_anon.first);
-                        dentry->d_flags |= DCACHE_UNHASHED;
-                        hlist_bl_del_init(&dentry->d_hash);
-                        __bit_spin_unlock(0,
-                                (unsigned long *)&dentry->d_sb->s_anon.first);
-                } else {
-                        struct dcache_hash_bucket *b;
+        if (!d_unhashed(dentry)) {
+                struct hlist_bl_head *b;
+                if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
+                        b = &dentry->d_sb->s_anon;
+                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);
-                }
+
+                hlist_bl_lock(b);
+                __hlist_bl_del(&dentry->d_hash);
+                dentry->d_hash.pprev = NULL;
+                hlist_bl_unlock(b);
+
+                dentry_rcuwalk_barrier(dentry);
         }
 }
 EXPORT_SYMBOL(__d_drop);
@@ -1304,7 +1282,7 @@ 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;
@@ -1606,10 +1584,9 @@ 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;
+        hlist_bl_lock(&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);
+        hlist_bl_unlock(&tmp->d_sb->s_anon);
         spin_unlock(&tmp->d_lock);
         spin_unlock(&inode->i_lock);
         security_d_instantiate(tmp, inode);
@@ -1789,7 +1766,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
         unsigned int len = name->len;
         unsigned int hash = name->hash;
         const unsigned char *str = name->name;
-        struct dcache_hash_bucket *b = d_hash(parent, hash);
+        struct hlist_bl_head *b = d_hash(parent, hash);
         struct hlist_bl_node *node;
         struct dentry *dentry;
 
@@ -1813,7 +1790,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
          *
          * See Documentation/filesystems/path-lookup.txt for more details.
          */
-        hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
+        hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
                 struct inode *i;
                 const char *tname;
                 int tlen;
@@ -1908,7 +1885,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
         unsigned int len = name->len;
         unsigned int hash = name->hash;
         const unsigned char *str = name->name;
-        struct dcache_hash_bucket *b = d_hash(parent, hash);
+        struct hlist_bl_head *b = d_hash(parent, hash);
         struct hlist_bl_node *node;
         struct dentry *found = NULL;
         struct dentry *dentry;
@@ -1935,7 +1912,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
          */
         rcu_read_lock();
         
-        hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
+        hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
                 const char *tname;
                 int tlen;
 
@@ -2086,13 +2063,13 @@ again:
 }
 EXPORT_SYMBOL(d_delete);
 
-static void __d_rehash(struct dentry * entry, struct dcache_hash_bucket *b)
+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;
-        hlist_bl_add_head_rcu(&entry->d_hash, &b->head);
-        spin_unlock_bucket(b);
+        hlist_bl_lock(b);
+        entry->d_flags |= DCACHE_RCUACCESS;
+        hlist_bl_add_head_rcu(&entry->d_hash, b);
+        hlist_bl_unlock(b);
 }
 
 static void _d_rehash(struct dentry * entry)
@@ -2131,7 +2108,7 @@ EXPORT_SYMBOL(d_rehash);
  */
 void dentry_update_name_case(struct dentry *dentry, struct qstr *name)
 {
-        BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
+        BUG_ON(!mutex_is_locked(&dentry->d_parent->d_inode->i_mutex));
         BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */
 
         spin_lock(&dentry->d_lock);
@@ -3025,7 +3002,7 @@ static void __init dcache_init_early(void)
 
         dentry_hashtable =
                 alloc_large_system_hash("Dentry cache",
-                                        sizeof(struct dcache_hash_bucket),
+                                        sizeof(struct hlist_bl_head),
                                         dhash_entries,
                                         13,
                                         HASH_EARLY,
@@ -3034,7 +3011,7 @@ static void __init dcache_init_early(void)
                                         0);
 
         for (loop = 0; loop < (1 << d_hash_shift); loop++)
-                INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
+                INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
 }
 
 static void __init dcache_init(void)
@@ -3057,7 +3034,7 @@ static void __init dcache_init(void)
 
         dentry_hashtable =
                 alloc_large_system_hash("Dentry cache",
-                                        sizeof(struct dcache_hash_bucket),
+                                        sizeof(struct hlist_bl_head),
                                         dhash_entries,
                                         13,
                                         0,
@@ -3066,7 +3043,7 @@ static void __init dcache_init(void)
                                         0);
 
         for (loop = 0; loop < (1 << d_hash_shift); loop++)
-                INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
+                INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
 }
 
 /* SLAB cache for __getname() consumers */