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

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
...@@ -586,6 +586,21 @@ static inline void path_to_nameidata(const struct path *path, ...@@ -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) ...@@ -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) { if (unlikely(error))
nd->flags |= LOOKUP_JUMPED; put_link(nd, link, *p);
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))
put_link(nd, link, *p);
return error; return error;
......
...@@ -1438,8 +1438,7 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd) ...@@ -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);
......
...@@ -80,6 +80,8 @@ extern int follow_up(struct path *); ...@@ -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;
......
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