Commit 0a959df5 authored by Al Viro's avatar Al Viro
Browse files

namei.c: separate the parts of follow_link() that find the link body 



Split a piece of fs/namei.c:follow_link() that does obtaining the link
body into a separate function.  follow_link() itself is converted to
calling get_link() and then doing the body traversal (if any).

The next step will expand follow_link() call in link_path_walk()
and this helps to keep the size down...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 680baacb

fs/namei.c

+36 −29
Original line number Diff line number Diff line
@@ -836,21 +836,22 @@ static int may_linkat(struct path *link) 
	return -EPERM;

}



static __always_inline int

follow_link(struct path *link, struct nameidata *nd, void **p)

static __always_inline const char *

get_link(struct path *link, struct nameidata *nd, void **p)

{

	struct dentry *dentry = link->dentry;

	struct inode *inode = dentry->d_inode;

	int error;

	const char *s;

	const char *res;



	BUG_ON(nd->flags & LOOKUP_RCU);



	if (link->mnt == nd->path.mnt)

		mntget(link->mnt);



	error = -ELOOP;

	res = ERR_PTR(-ELOOP);

	if (unlikely(current->total_link_count >= 40))

		goto out_put_nd_path;

		goto out;



	cond_resched();

	current->total_link_count++;
@@ -858,18 +859,31 @@ follow_link(struct path *link, struct nameidata *nd, void **p) 
	touch_atime(link);



	error = security_inode_follow_link(dentry);

	res = ERR_PTR(error);

	if (error)

		goto out_put_nd_path;

		goto out;



	nd->last_type = LAST_BIND;

	*p = NULL;

	s = dentry->d_inode->i_op->follow_link(dentry, p, nd);

	error = PTR_ERR(s);

	if (IS_ERR(s))

		goto out_put_nd_path;

	res = inode->i_op->follow_link(dentry, p, nd);

	if (IS_ERR(res)) {

out:

		path_put(&nd->path);

		path_put(link);

	}

	return res;

}



	error = 0;

	if (s) {

static __always_inline int

follow_link(struct path *link, struct nameidata *nd, void **p)

{

	const char *s = get_link(link, nd, p);

	int error;



	if (unlikely(IS_ERR(s)))

		return PTR_ERR(s);

	if (unlikely(!s))

		return 0;

	if (*s == '/') {

		if (!nd->root.mnt)

			set_root(nd);
@@ -882,13 +896,6 @@ follow_link(struct path *link, struct nameidata *nd, void **p) 
	error = link_path_walk(s, nd);

	if (unlikely(error))

		put_link(nd, link, *p);

	}



	return error;



out_put_nd_path:

	path_put(&nd->path);

	path_put(link);

	return error;

}

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