Commit ad6cc4c3 authored by Al Viro's avatar Al Viro
Browse files

finally fold get_link() into pick_link() 



kill nd->link_inode, while we are at it

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 06708adb

fs/namei.c

+61 −74
Original line number Diff line number Diff line
@@ -503,7 +503,6 @@ struct nameidata { 
	} *stack, internal[EMBEDDED_LEVELS];

	struct filename	*name;

	struct nameidata *saved;

	struct inode	*link_inode;

	unsigned	root_seq;

	int		dfd;

} __randomize_layout;
@@ -962,9 +961,8 @@ int sysctl_protected_regular __read_mostly; 
 *

 * Returns 0 if following the symlink is allowed, -ve on error.

 */

static inline int may_follow_link(struct nameidata *nd)

static inline int may_follow_link(struct nameidata *nd, const struct inode *inode)

{

	const struct inode *inode;

	const struct inode *parent;

	kuid_t puid;
@@ -972,7 +970,6 @@ static inline int may_follow_link(struct nameidata *nd) 
		return 0;



	/* Allowed if owner and follower match. */

	inode = nd->link_inode;

	if (uid_eq(current_cred()->fsuid, inode->i_uid))

		return 0;
@@ -1106,73 +1103,6 @@ static int may_create_in_sticky(umode_t dir_mode, kuid_t dir_uid, 
	return 0;

}



static __always_inline

const char *get_link(struct nameidata *nd)

{

	struct saved *last = nd->stack + nd->depth - 1;

	struct dentry *dentry = last->link.dentry;

	struct inode *inode = nd->link_inode;

	int error;

	const char *res;



	if (!(nd->flags & LOOKUP_PARENT)) {

		error = may_follow_link(nd);

		if (unlikely(error))

			return ERR_PTR(error);

	}



	if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS))

		return ERR_PTR(-ELOOP);



	if (!(nd->flags & LOOKUP_RCU)) {

		touch_atime(&last->link);

		cond_resched();

	} else if (atime_needs_update(&last->link, inode)) {

		if (unlikely(unlazy_walk(nd)))

			return ERR_PTR(-ECHILD);

		touch_atime(&last->link);

	}



	error = security_inode_follow_link(dentry, inode,

					   nd->flags & LOOKUP_RCU);

	if (unlikely(error))

		return ERR_PTR(error);



	nd->last_type = LAST_BIND;

	res = READ_ONCE(inode->i_link);

	if (!res) {

		const char * (*get)(struct dentry *, struct inode *,

				struct delayed_call *);

		get = inode->i_op->get_link;

		if (nd->flags & LOOKUP_RCU) {

			res = get(NULL, inode, &last->done);

			if (res == ERR_PTR(-ECHILD)) {

				if (unlikely(unlazy_walk(nd)))

					return ERR_PTR(-ECHILD);

				res = get(dentry, inode, &last->done);

			}

		} else {

			res = get(dentry, inode, &last->done);

		}

		if (!res)

			goto all_done;

		if (IS_ERR(res))

			return res;

	}

	if (*res == '/') {

		error = nd_jump_root(nd);

		if (unlikely(error))

			return ERR_PTR(error);

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

			;

	}

	if (*res)

		return res;

all_done: // pure jump

	put_link(nd);

	return NULL;

}



/*

 * follow_up - Find the mountpoint of path's vfsmount

 *
@@ -1796,8 +1726,10 @@ static inline int handle_dots(struct nameidata *nd, int type) 
static const char *pick_link(struct nameidata *nd, struct path *link,

		     struct inode *inode, unsigned seq)

{

	int error;

	struct saved *last;

	const char *res;

	int error;



	if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {

		path_to_nameidata(link, nd);

		return ERR_PTR(-ELOOP);
@@ -1828,9 +1760,64 @@ static const char *pick_link(struct nameidata *nd, struct path *link, 
	last = nd->stack + nd->depth++;

	last->link = *link;

	clear_delayed_call(&last->done);

	nd->link_inode = inode;

	last->seq = seq;

	return get_link(nd);



	if (!(nd->flags & LOOKUP_PARENT)) {

		error = may_follow_link(nd, inode);

		if (unlikely(error))

			return ERR_PTR(error);

	}



	if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS))

		return ERR_PTR(-ELOOP);



	if (!(nd->flags & LOOKUP_RCU)) {

		touch_atime(&last->link);

		cond_resched();

	} else if (atime_needs_update(&last->link, inode)) {

		if (unlikely(unlazy_walk(nd)))

			return ERR_PTR(-ECHILD);

		touch_atime(&last->link);

	}



	error = security_inode_follow_link(link->dentry, inode,

					   nd->flags & LOOKUP_RCU);

	if (unlikely(error))

		return ERR_PTR(error);



	nd->last_type = LAST_BIND;

	res = READ_ONCE(inode->i_link);

	if (!res) {

		const char * (*get)(struct dentry *, struct inode *,

				struct delayed_call *);

		get = inode->i_op->get_link;

		if (nd->flags & LOOKUP_RCU) {

			res = get(NULL, inode, &last->done);

			if (res == ERR_PTR(-ECHILD)) {

				if (unlikely(unlazy_walk(nd)))

					return ERR_PTR(-ECHILD);

				res = get(link->dentry, inode, &last->done);

			}

		} else {

			res = get(link->dentry, inode, &last->done);

		}

		if (!res)

			goto all_done;

		if (IS_ERR(res))

			return res;

	}

	if (*res == '/') {

		error = nd_jump_root(nd);

		if (unlikely(error))

			return ERR_PTR(error);

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

			;

	}

	if (*res)

		return res;

all_done: // pure jump

	put_link(nd);

	return NULL;

}



enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};