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Commit b5fb63c1 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

fs: add nd_jump_link 



Add a helper that abstracts out the jump to an already parsed struct path
from ->follow_link operation from procfs.  Not only does this clean up
the code by moving the two sides of this game into a single helper, but
it also prepares for making struct nameidata private to namei.c

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 408ef013

fs/namei.c

+17 −10
Original line number Original line Diff line number Diff line
@@ -586,6 +586,21 @@ static inline void path_to_nameidata(const struct path *path, 
	nd->path.dentry = path->dentry;

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

}

}





/*

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

 * caller must have taken a reference to path beforehand.

 */

void nd_jump_link(struct nameidata *nd, struct path *path)

{

	path_put(&nd->path);



	nd->path = *path;

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

	nd->flags |= LOOKUP_JUMPED;



	BUG_ON(nd->inode->i_op->follow_link);

}



static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)

static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)

{

{

	struct inode *inode = link->dentry->d_inode;

	struct inode *inode = link->dentry->d_inode;
@@ -630,17 +645,9 @@ follow_link(struct path *link, struct nameidata *nd, void **p) 
	s = nd_get_link(nd);

	s = nd_get_link(nd);

	if (s) {

	if (s) {

		error = __vfs_follow_link(nd, s);

		error = __vfs_follow_link(nd, s);

	} else if (nd->last_type == LAST_BIND) {

		nd->flags |= LOOKUP_JUMPED;

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

		if (nd->inode->i_op->follow_link) {

			/* stepped on a _really_ weird one */

			path_put(&nd->path);

			error = -ELOOP;

		}

	}

		if (unlikely(error))

		if (unlikely(error))

			put_link(nd, link, *p);

			put_link(nd, link, *p);

	}





	return error;

	return error;

fs/proc/base.c

+1 −2
Original line number Original line Diff line number Diff line
@@ -1438,8 +1438,7 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd) 
	if (error)

	if (error)

		goto out;

		goto out;





	path_put(&nd->path);

	nd_jump_link(nd, &path);

	nd->path = path;

	return NULL;

	return NULL;

out:

out:

	return ERR_PTR(error);

	return ERR_PTR(error);

include/linux/namei.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -80,6 +80,8 @@ extern int follow_up(struct path *); 
extern struct dentry *lock_rename(struct dentry *, struct dentry *);

extern struct dentry *lock_rename(struct dentry *, struct dentry *);

extern void unlock_rename(struct dentry *, struct dentry *);

extern void unlock_rename(struct dentry *, struct dentry *);





extern void nd_jump_link(struct nameidata *nd, struct path *path);



static inline void nd_set_link(struct nameidata *nd, char *path)

static inline void nd_set_link(struct nameidata *nd, char *path)

{

{

	nd->saved_names[nd->depth] = path;

	nd->saved_names[nd->depth] = path;