1 files changed, 17 insertions, 9 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 90de0e498371..45b6919903e6 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -17,7 +17,7 @@
 
 #include "kernfs-internal.h"
 
-static DEFINE_SPINLOCK(kernfs_rename_lock);	/* kn->parent and ->name */
+static DEFINE_RWLOCK(kernfs_rename_lock);	/* kn->parent and ->name */
 /*
  * Don't use rename_lock to piggy back on pr_cont_buf. We don't want to
  * call pr_cont() while holding rename_lock. Because sometimes pr_cont()
@@ -196,9 +196,9 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
 	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&kernfs_rename_lock, flags);
+	read_lock_irqsave(&kernfs_rename_lock, flags);
 	ret = kernfs_name_locked(kn, buf, buflen);
-	spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+	read_unlock_irqrestore(&kernfs_rename_lock, flags);
 	return ret;
 }
 
@@ -224,9 +224,9 @@ int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
 	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&kernfs_rename_lock, flags);
+	read_lock_irqsave(&kernfs_rename_lock, flags);
 	ret = kernfs_path_from_node_locked(to, from, buf, buflen);
-	spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+	read_unlock_irqrestore(&kernfs_rename_lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(kernfs_path_from_node);
@@ -294,10 +294,10 @@ struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
 	struct kernfs_node *parent;
 	unsigned long flags;
 
-	spin_lock_irqsave(&kernfs_rename_lock, flags);
+	read_lock_irqsave(&kernfs_rename_lock, flags);
 	parent = kn->parent;
 	kernfs_get(parent);
-	spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+	read_unlock_irqrestore(&kernfs_rename_lock, flags);
 
 	return parent;
 }
@@ -770,12 +770,15 @@ int kernfs_add_one(struct kernfs_node *kn)
 		goto out_unlock;
 
 	/* Update timestamps on the parent */
+	down_write(&root->kernfs_iattr_rwsem);
+
 	ps_iattr = parent->iattr;
 	if (ps_iattr) {
 		ktime_get_real_ts64(&ps_iattr->ia_ctime);
 		ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 	}
 
+	up_write(&root->kernfs_iattr_rwsem);
 	up_write(&root->kernfs_rwsem);
 
 	/*
@@ -940,6 +943,8 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
 
 	idr_init(&root->ino_idr);
 	init_rwsem(&root->kernfs_rwsem);
+	init_rwsem(&root->kernfs_iattr_rwsem);
+	init_rwsem(&root->kernfs_supers_rwsem);
 	INIT_LIST_HEAD(&root->supers);
 
 	/*
@@ -1462,11 +1467,14 @@ static void __kernfs_remove(struct kernfs_node *kn)
 				pos->parent ? pos->parent->iattr : NULL;
 
 			/* update timestamps on the parent */
+			down_write(&kernfs_root(kn)->kernfs_iattr_rwsem);
+
 			if (ps_iattr) {
 				ktime_get_real_ts64(&ps_iattr->ia_ctime);
 				ps_iattr->ia_mtime = ps_iattr->ia_ctime;
 			}
 
+			up_write(&kernfs_root(kn)->kernfs_iattr_rwsem);
 			kernfs_put(pos);
 		}
 
@@ -1723,7 +1731,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
 	kernfs_get(new_parent);
 
 	/* rename_lock protects ->parent and ->name accessors */
-	spin_lock_irq(&kernfs_rename_lock);
+	write_lock_irq(&kernfs_rename_lock);
 
 	old_parent = kn->parent;
 	kn->parent = new_parent;
@@ -1734,7 +1742,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
 		kn->name = new_name;
 	}
 
-	spin_unlock_irq(&kernfs_rename_lock);
+	write_unlock_irq(&kernfs_rename_lock);
 
 	kn->hash = kernfs_name_hash(kn->name, kn->ns);
 	kernfs_link_sibling(kn);