Commit 248fb5b9 authored by Al Viro's avatar Al Viro
Browse files

namei.c: take "jump to root" into a new helper 



... and use it both in path_init() (for absolute pathnames) and
get_link() (for absolute symlinks).

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ef55d917

fs/namei.c

+26 −28
Original line number Diff line number Diff line
@@ -841,6 +841,26 @@ static inline void path_to_nameidata(const struct path *path, 
	nd->path.dentry = path->dentry;

}



static int nd_jump_root(struct nameidata *nd)

{

	if (nd->flags & LOOKUP_RCU) {

		struct dentry *d;

		nd->path = nd->root;

		d = nd->path.dentry;

		nd->inode = d->d_inode;

		nd->seq = nd->root_seq;

		if (unlikely(read_seqcount_retry(&d->d_seq, nd->seq)))

			return -ECHILD;

	} else {

		path_put(&nd->path);

		nd->path = nd->root;

		path_get(&nd->path);

		nd->inode = nd->path.dentry->d_inode;

	}

	nd->flags |= LOOKUP_JUMPED;

	return 0;

}



/*

 * Helper to directly jump to a known parsed path from ->follow_link,

 * caller must have taken a reference to path beforehand.
@@ -1017,21 +1037,8 @@ const char *get_link(struct nameidata *nd) 
	if (*res == '/') {

		if (!nd->root.mnt)

			set_root(nd);

		if (nd->flags & LOOKUP_RCU) {

			struct dentry *d;

			nd->path = nd->root;

			d = nd->path.dentry;

			nd->inode = d->d_inode;

			nd->seq = nd->root_seq;

			if (unlikely(read_seqcount_retry(&d->d_seq, nd->seq)))

		if (unlikely(nd_jump_root(nd)))

			return ERR_PTR(-ECHILD);

		} else {

			path_put(&nd->path);

			nd->path = nd->root;

			path_get(&nd->root);

			nd->inode = nd->path.dentry->d_inode;

		}

		nd->flags |= LOOKUP_JUMPED;

		while (unlikely(*++res == '/'))

			;

	}
@@ -2015,25 +2022,16 @@ static const char *path_init(struct nameidata *nd, unsigned flags) 
	}



	nd->root.mnt = NULL;

	nd->path.mnt = NULL;

	nd->path.dentry = NULL;



	nd->m_seq = read_seqbegin(&mount_lock);

	if (*s == '/') {

		if (flags & LOOKUP_RCU)

			rcu_read_lock();

		set_root(nd);

		if (flags & LOOKUP_RCU) {

			nd->seq = nd->root_seq;

			nd->path = nd->root;

		} else {

			path_get(&nd->root);

			nd->path = nd->root;

		}

		nd->inode = nd->path.dentry->d_inode;

		if (!(flags & LOOKUP_RCU))

		if (likely(!nd_jump_root(nd)))

			return s;

		if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))

			return s;

		if (!(nd->flags & LOOKUP_ROOT))

		nd->root.mnt = NULL;

		rcu_read_unlock();

		return ERR_PTR(-ECHILD);