1 files changed, 79 insertions, 48 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index c6d996ee2d61..7c38f39958bc 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -37,8 +37,6 @@
 #include <linux/prefetch.h>
 #include <linux/ratelimit.h>
 #include <linux/list_lru.h>
-#include <linux/kasan.h>
-
 #include "internal.h"
 #include "mount.h"
 
@@ -193,7 +191,7 @@ static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char
 	unsigned long a,b,mask;
 
 	for (;;) {
-		a = *(unsigned long *)cs;
+		a = read_word_at_a_time(cs);
 		b = load_unaligned_zeropad(ct);
 		if (tcount < sizeof(unsigned long))
 			break;
@@ -466,9 +464,11 @@ static void dentry_lru_add(struct dentry *dentry)
  * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
  * reason (NFS timeouts or autofs deletes).
  *
- * __d_drop requires dentry->d_lock.
+ * __d_drop requires dentry->d_lock
+ * ___d_drop doesn't mark dentry as "unhashed"
+ *   (dentry->d_hash.pprev will be LIST_POISON2, not NULL).
  */
-void __d_drop(struct dentry *dentry)
+static void ___d_drop(struct dentry *dentry)
 {
 	if (!d_unhashed(dentry)) {
 		struct hlist_bl_head *b;
@@ -484,12 +484,17 @@ void __d_drop(struct dentry *dentry)
 
 		hlist_bl_lock(b);
 		__hlist_bl_del(&dentry->d_hash);
-		dentry->d_hash.pprev = NULL;
 		hlist_bl_unlock(b);
 		/* After this call, in-progress rcu-walk path lookup will fail. */
 		write_seqcount_invalidate(&dentry->d_seq);
 	}
 }
+
+void __d_drop(struct dentry *dentry)
+{
+	___d_drop(dentry);
+	dentry->d_hash.pprev = NULL;
+}
 EXPORT_SYMBOL(__d_drop);
 
 void d_drop(struct dentry *dentry)
@@ -1621,9 +1626,6 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
 		}
 		atomic_set(&p->u.count, 1);
 		dname = p->name;
-		if (IS_ENABLED(CONFIG_DCACHE_WORD_ACCESS))
-			kasan_unpoison_shadow(dname,
-				round_up(name->len + 1,	sizeof(unsigned long)));
 	} else  {
 		dname = dentry->d_iname;
 	}	
@@ -1696,9 +1698,15 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
 }
 EXPORT_SYMBOL(d_alloc);
 
+struct dentry *d_alloc_anon(struct super_block *sb)
+{
+	return __d_alloc(sb, NULL);
+}
+EXPORT_SYMBOL(d_alloc_anon);
+
 struct dentry *d_alloc_cursor(struct dentry * parent)
 {
-	struct dentry *dentry = __d_alloc(parent->d_sb, NULL);
+	struct dentry *dentry = d_alloc_anon(parent->d_sb);
 	if (dentry) {
 		dentry->d_flags |= DCACHE_RCUACCESS | DCACHE_DENTRY_CURSOR;
 		dentry->d_parent = dget(parent);
@@ -1884,7 +1892,7 @@ struct dentry *d_make_root(struct inode *root_inode)
 	struct dentry *res = NULL;
 
 	if (root_inode) {
-		res = __d_alloc(root_inode->i_sb, NULL);
+		res = d_alloc_anon(root_inode->i_sb);
 		if (res)
 			d_instantiate(res, root_inode);
 		else
@@ -1923,33 +1931,19 @@ struct dentry *d_find_any_alias(struct inode *inode)
 }
 EXPORT_SYMBOL(d_find_any_alias);
 
-static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
+static struct dentry *__d_instantiate_anon(struct dentry *dentry,
+					   struct inode *inode,
+					   bool disconnected)
 {
-	struct dentry *tmp;
 	struct dentry *res;
 	unsigned add_flags;
 
-	if (!inode)
-		return ERR_PTR(-ESTALE);
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	res = d_find_any_alias(inode);
-	if (res)
-		goto out_iput;
-
-	tmp = __d_alloc(inode->i_sb, NULL);
-	if (!tmp) {
-		res = ERR_PTR(-ENOMEM);
-		goto out_iput;
-	}
-
-	security_d_instantiate(tmp, inode);
+	security_d_instantiate(dentry, inode);
 	spin_lock(&inode->i_lock);
 	res = __d_find_any_alias(inode);
 	if (res) {
 		spin_unlock(&inode->i_lock);
-		dput(tmp);
+		dput(dentry);
 		goto out_iput;
 	}
 
@@ -1959,24 +1953,57 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 	if (disconnected)
 		add_flags |= DCACHE_DISCONNECTED;
 
-	spin_lock(&tmp->d_lock);
-	__d_set_inode_and_type(tmp, inode, add_flags);
-	hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
+	spin_lock(&dentry->d_lock);
+	__d_set_inode_and_type(dentry, inode, add_flags);
+	hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
 	if (!disconnected) {
-		hlist_bl_lock(&tmp->d_sb->s_roots);
-		hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_roots);
-		hlist_bl_unlock(&tmp->d_sb->s_roots);
+		hlist_bl_lock(&dentry->d_sb->s_roots);
+		hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots);
+		hlist_bl_unlock(&dentry->d_sb->s_roots);
 	}
-	spin_unlock(&tmp->d_lock);
+	spin_unlock(&dentry->d_lock);
 	spin_unlock(&inode->i_lock);
 
-	return tmp;
+	return dentry;
 
  out_iput:
 	iput(inode);
 	return res;
 }
 
+struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode)
+{
+	return __d_instantiate_anon(dentry, inode, true);
+}
+EXPORT_SYMBOL(d_instantiate_anon);
+
+static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected)
+{
+	struct dentry *tmp;
+	struct dentry *res;
+
+	if (!inode)
+		return ERR_PTR(-ESTALE);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	res = d_find_any_alias(inode);
+	if (res)
+		goto out_iput;
+
+	tmp = d_alloc_anon(inode->i_sb);
+	if (!tmp) {
+		res = ERR_PTR(-ENOMEM);
+		goto out_iput;
+	}
+
+	return __d_instantiate_anon(tmp, inode, disconnected);
+
+out_iput:
+	iput(inode);
+	return res;
+}
+
 /**
  * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
  * @inode: inode to allocate the dentry for
@@ -1997,7 +2024,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
  */
 struct dentry *d_obtain_alias(struct inode *inode)
 {
-	return __d_obtain_alias(inode, 1);
+	return __d_obtain_alias(inode, true);
 }
 EXPORT_SYMBOL(d_obtain_alias);
 
@@ -2018,7 +2045,7 @@ EXPORT_SYMBOL(d_obtain_alias);
  */
 struct dentry *d_obtain_root(struct inode *inode)
 {
-	return __d_obtain_alias(inode, 0);
+	return __d_obtain_alias(inode, false);
 }
 EXPORT_SYMBOL(d_obtain_root);
 
@@ -2380,7 +2407,7 @@ EXPORT_SYMBOL(d_delete);
 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);
@@ -2815,9 +2842,9 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
 	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. */
-	__d_drop(dentry);
-	__d_drop(target);
+	/* ___d_drop does write_seqcount_barrier, but they're OK to nest. */
+	___d_drop(dentry);
+	___d_drop(target);
 
 	/* Switch the names.. */
 	if (exchange)
@@ -2829,6 +2856,8 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
 	__d_rehash(dentry);
 	if (exchange)
 		__d_rehash(target);
+	else
+		target->d_hash.pprev = NULL;
 
 	/* ... and switch them in the tree */
 	if (IS_ROOT(dentry)) {
@@ -3523,6 +3552,7 @@ bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry)
 
 	return result;
 }
+EXPORT_SYMBOL(is_subdir);
 
 static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
 {
@@ -3598,8 +3628,9 @@ static void __init dcache_init(void)
 	 * but it is probably not worth it because of the cache nature
 	 * of the dcache.
 	 */
-	dentry_cache = KMEM_CACHE(dentry,
-		SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT);
+	dentry_cache = KMEM_CACHE_USERCOPY(dentry,
+		SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,
+		d_iname);
 
 	/* Hash may have been set up in dcache_init_early */
 	if (!hashdist)
@@ -3637,8 +3668,8 @@ void __init vfs_caches_init_early(void)
 
 void __init vfs_caches_init(void)
 {
-	names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
+			SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
 
 	dcache_init();
 	inode_init();