1 files changed, 48 insertions, 30 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index bcbdb33fcc20..b80531c91779 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -23,7 +23,7 @@
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/cache.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/mount.h>
 #include <linux/file.h>
 #include <asm/uaccess.h>
@@ -105,10 +105,10 @@ 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(const struct dentry *parent,
-					unsigned long hash)
+					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);
 }
 
@@ -141,6 +141,45 @@ int proc_nr_dentry(ctl_table *table, int write, void __user *buffer,
  * Compare 2 name strings, return 0 if they match, otherwise non-zero.
  * The strings are both count bytes long, and count is non-zero.
  */
+#ifdef CONFIG_DCACHE_WORD_ACCESS
+
+#include <asm/word-at-a-time.h>
+/*
+ * NOTE! 'cs' and 'scount' come from a dentry, so it has a
+ * aligned allocation for this particular component. We don't
+ * strictly need the load_unaligned_zeropad() safety, but it
+ * doesn't hurt either.
+ *
+ * In contrast, 'ct' and 'tcount' can be from a pathname, and do
+ * need the careful unaligned handling.
+ */
+static inline int dentry_cmp(const unsigned char *cs, size_t scount,
+				const unsigned char *ct, size_t tcount)
+{
+	unsigned long a,b,mask;
+
+	if (unlikely(scount != tcount))
+		return 1;
+
+	for (;;) {
+		a = load_unaligned_zeropad(cs);
+		b = load_unaligned_zeropad(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
+
 static inline int dentry_cmp(const unsigned char *cs, size_t scount,
 				const unsigned char *ct, size_t tcount)
 {
@@ -157,6 +196,8 @@ static inline int dentry_cmp(const unsigned char *cs, size_t scount,
 	return 0;
 }
 
+#endif
+
 static void __d_free(struct rcu_head *head)
 {
 	struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
@@ -1443,30 +1484,6 @@ 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;
@@ -1714,7 +1731,7 @@ 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
  *
@@ -2405,6 +2422,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 			if (d_ancestor(alias, dentry)) {
 				/* Check for loops */
 				actual = ERR_PTR(-ELOOP);
+				spin_unlock(&inode->i_lock);
 			} else if (IS_ROOT(alias)) {
 				/* Is this an anonymous mountpoint that we
 				 * could splice into our tree? */
@@ -2414,7 +2432,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 				goto found;
 			} else {
 				/* Nope, but we must(!) avoid directory
-				 * aliasing */
+				 * aliasing. This drops inode->i_lock */
 				actual = __d_unalias(inode, dentry, alias);
 			}
 			write_sequnlock(&rename_lock);