3 files changed, 66 insertions, 21 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 91e004518..996b7742c 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -541,14 +541,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 	if (!kn)
 		goto err_out1;
 
-	/*
-	 * If the ino of the sysfs entry created for a kmem cache gets
-	 * allocated from an ida layer, which is accounted to the memcg that
-	 * owns the cache, the memcg will get pinned forever. So do not account
-	 * ino ida allocations.
-	 */
-	ret = ida_simple_get(&root->ino_ida, 1, 0,
-			     GFP_KERNEL | __GFP_NOACCOUNT);
+	ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
 	if (ret < 0)
 		goto err_out2;
 	kn->ino = ret;
@@ -694,6 +687,29 @@ static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
 	return NULL;
 }
 
+static struct kernfs_node *kernfs_walk_ns(struct kernfs_node *parent,
+					  const unsigned char *path,
+					  const void *ns)
+{
+	static char path_buf[PATH_MAX];	/* protected by kernfs_mutex */
+	size_t len = strlcpy(path_buf, path, PATH_MAX);
+	char *p = path_buf;
+	char *name;
+
+	lockdep_assert_held(&kernfs_mutex);
+
+	if (len >= PATH_MAX)
+		return NULL;
+
+	while ((name = strsep(&p, "/")) && parent) {
+		if (*name == '\0')
+			continue;
+		parent = kernfs_find_ns(parent, name, ns);
+	}
+
+	return parent;
+}
+
 /**
  * kernfs_find_and_get_ns - find and get kernfs_node with the given name
  * @parent: kernfs_node to search under
@@ -719,6 +735,29 @@ struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
 EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
 
 /**
+ * kernfs_walk_and_get_ns - find and get kernfs_node with the given path
+ * @parent: kernfs_node to search under
+ * @path: path to look for
+ * @ns: the namespace tag to use
+ *
+ * Look for kernfs_node with path @path under @parent and get a reference
+ * if found.  This function may sleep and returns pointer to the found
+ * kernfs_node on success, %NULL on failure.
+ */
+struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
+					   const char *path, const void *ns)
+{
+	struct kernfs_node *kn;
+
+	mutex_lock(&kernfs_mutex);
+	kn = kernfs_walk_ns(parent, path, ns);
+	kernfs_get(kn);
+	mutex_unlock(&kernfs_mutex);
+
+	return kn;
+}
+
+/**
  * kernfs_create_root - create a new kernfs hierarchy
  * @scops: optional syscall operations for the hierarchy
  * @flags: KERNFS_ROOT_* flags
@@ -1472,9 +1511,9 @@ static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
 	struct inode *inode = file_inode(file);
 	loff_t ret;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 	ret = generic_file_llseek(file, offset, whence);
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 
 	return ret;
 }
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 756dd56aa..16405ae88 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -205,7 +205,7 @@ int kernfs_iop_removexattr(struct dentry *dentry, const char *name)
 	if (!attrs)
 		return -ENOMEM;
 
-	return simple_xattr_remove(&attrs->xattrs, name);
+	return simple_xattr_set(&attrs->xattrs, name, NULL, 0, XATTR_REPLACE);
 }
 
 ssize_t kernfs_iop_getxattr(struct dentry *dentry, const char *name, void *buf,
@@ -230,7 +230,7 @@ ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
 	if (!attrs)
 		return -ENOMEM;
 
-	return simple_xattr_list(&attrs->xattrs, buf, size);
+	return simple_xattr_list(d_inode(dentry), &attrs->xattrs, buf, size);
 }
 
 static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index db272528a..117b8b341 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -112,18 +112,25 @@ static int kernfs_getlink(struct dentry *dentry, char *path)
 	return error;
 }
 
-static const char *kernfs_iop_follow_link(struct dentry *dentry, void **cookie)
+static const char *kernfs_iop_get_link(struct dentry *dentry,
+				       struct inode *inode,
+				       struct delayed_call *done)
 {
-	int error = -ENOMEM;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	if (!page)
+	char *body;
+	int error;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!body)
 		return ERR_PTR(-ENOMEM);
-	error = kernfs_getlink(dentry, (char *)page);
+	error = kernfs_getlink(dentry, body);
 	if (unlikely(error < 0)) {
-		free_page((unsigned long)page);
+		kfree(body);
 		return ERR_PTR(error);
 	}
-	return *cookie = (char *)page;
+	set_delayed_call(done, kfree_link, body);
+	return body;
 }
 
 const struct inode_operations kernfs_symlink_iops = {
@@ -132,8 +139,7 @@ const struct inode_operations kernfs_symlink_iops = {
 	.getxattr	= kernfs_iop_getxattr,
 	.listxattr	= kernfs_iop_listxattr,
 	.readlink	= generic_readlink,
-	.follow_link	= kernfs_iop_follow_link,
-	.put_link	= free_page_put_link,
+	.get_link	= kernfs_iop_get_link,
 	.setattr	= kernfs_iop_setattr,
 	.getattr	= kernfs_iop_getattr,
 	.permission	= kernfs_iop_permission,