1 files changed, 55 insertions, 33 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 303ebd98bc80..e9a07b2a0948 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -104,11 +104,11 @@ static unsigned int d_hash_shift __read_mostly;
 
 static struct hlist_bl_head *dentry_hashtable __read_mostly;
 
-static inline struct hlist_bl_head *d_hash(struct dentry *parent,
-					unsigned long hash)
+static inline struct hlist_bl_head *d_hash(const struct dentry *parent,
+					unsigned int hash)
 {
-	hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
-	hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
+	hash += (unsigned long) parent / L1_CACHE_BYTES;
+	hash = hash + (hash >> D_HASHBITS);
 	return dentry_hashtable + (hash & D_HASHMASK);
 }
 
@@ -137,6 +137,49 @@ int proc_nr_dentry(ctl_table *table, int write, void __user *buffer,
 }
 #endif
 
+/*
+ * Compare 2 name strings, return 0 if they match, otherwise non-zero.
+ * The strings are both count bytes long, and count is non-zero.
+ */
+static inline int dentry_cmp(const unsigned char *cs, size_t scount,
+				const unsigned char *ct, size_t tcount)
+{
+#ifdef CONFIG_DCACHE_WORD_ACCESS
+	unsigned long a,b,mask;
+
+	if (unlikely(scount != tcount))
+		return 1;
+
+	for (;;) {
+		a = *(unsigned long *)cs;
+		b = *(unsigned long *)ct;
+		if (tcount < sizeof(unsigned long))
+			break;
+		if (unlikely(a != b))
+			return 1;
+		cs += sizeof(unsigned long);
+		ct += sizeof(unsigned long);
+		tcount -= sizeof(unsigned long);
+		if (!tcount)
+			return 0;
+	}
+	mask = ~(~0ul << tcount*8);
+	return unlikely(!!((a ^ b) & mask));
+#else
+	if (scount != tcount)
+		return 1;
+
+	do {
+		if (*cs != *ct)
+			return 1;
+		cs++;
+		ct++;
+		tcount--;
+	} while (tcount);
+	return 0;
+#endif
+}
+
 static void __d_free(struct rcu_head *head)
 {
 	struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
@@ -1423,30 +1466,6 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
 
 EXPORT_SYMBOL(d_instantiate_unique);
 
-/**
- * d_alloc_root - allocate root dentry
- * @root_inode: inode to allocate the root for
- *
- * Allocate a root ("/") dentry for the inode given. The inode is
- * instantiated and returned. %NULL is returned if there is insufficient
- * memory or the inode passed is %NULL.
- */
- 
-struct dentry * d_alloc_root(struct inode * root_inode)
-{
-	struct dentry *res = NULL;
-
-	if (root_inode) {
-		static const struct qstr name = { .name = "/", .len = 1 };
-
-		res = __d_alloc(root_inode->i_sb, &name);
-		if (res)
-			d_instantiate(res, root_inode);
-	}
-	return res;
-}
-EXPORT_SYMBOL(d_alloc_root);
-
 struct dentry *d_make_root(struct inode *root_inode)
 {
 	struct dentry *res = NULL;
@@ -1694,7 +1713,7 @@ EXPORT_SYMBOL(d_add_ci);
  * __d_lookup_rcu - search for a dentry (racy, store-free)
  * @parent: parent dentry
  * @name: qstr of name we wish to find
- * @seq: returns d_seq value at the point where the dentry was found
+ * @seqp: returns d_seq value at the point where the dentry was found
  * @inode: returns dentry->d_inode when the inode was found valid.
  * Returns: dentry, or NULL
  *
@@ -1717,8 +1736,9 @@ EXPORT_SYMBOL(d_add_ci);
  * child is looked up. Thus, an interlocking stepping of sequence lock checks
  * is formed, giving integrity down the path walk.
  */
-struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
-				unsigned *seq, struct inode **inode)
+struct dentry *__d_lookup_rcu(const struct dentry *parent,
+				const struct qstr *name,
+				unsigned *seqp, struct inode **inode)
 {
 	unsigned int len = name->len;
 	unsigned int hash = name->hash;
@@ -1748,6 +1768,7 @@ 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, d_hash) {
+		unsigned seq;
 		struct inode *i;
 		const char *tname;
 		int tlen;
@@ -1756,7 +1777,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
 			continue;
 
 seqretry:
-		*seq = read_seqcount_begin(&dentry->d_seq);
+		seq = read_seqcount_begin(&dentry->d_seq);
 		if (dentry->d_parent != parent)
 			continue;
 		if (d_unhashed(dentry))
@@ -1771,7 +1792,7 @@ seqretry:
 		 * edge of memory when walking. If we could load this
 		 * atomically some other way, we could drop this check.
 		 */
-		if (read_seqcount_retry(&dentry->d_seq, *seq))
+		if (read_seqcount_retry(&dentry->d_seq, seq))
 			goto seqretry;
 		if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
 			if (parent->d_op->d_compare(parent, *inode,
@@ -1788,6 +1809,7 @@ seqretry:
 		 * order to do anything useful with the returned dentry
 		 * anyway.
 		 */
+		*seqp = seq;
 		*inode = i;
 		return dentry;
 	}