Commit 6d7b5aae authored by Al Viro's avatar Al Viro

namei.c: let follow_link() do put_link() on failure

no need for kludgy "set cookie to ERR_PTR(...) because we failed
before we did actual ->follow_link() and want to suppress put_link()",
no pointless check in put_link() itself.

Callers checked if follow_link() has failed anyway; might as well
break out of their loops if that happened, without bothering
to call put_link() first.

[AV: folded fixes from hch]
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1d674107
...@@ -605,7 +605,7 @@ static inline void path_to_nameidata(const struct path *path, ...@@ -605,7 +605,7 @@ static inline void path_to_nameidata(const struct path *path,
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;
if (!IS_ERR(cookie) && inode->i_op->put_link) if (inode->i_op->put_link)
inode->i_op->put_link(link->dentry, nd, cookie); inode->i_op->put_link(link->dentry, nd, cookie);
path_put(link); path_put(link);
} }
...@@ -613,19 +613,19 @@ static inline void put_link(struct nameidata *nd, struct path *link, void *cooki ...@@ -613,19 +613,19 @@ static inline void put_link(struct nameidata *nd, struct path *link, void *cooki
static __always_inline int static __always_inline int
follow_link(struct path *link, struct nameidata *nd, void **p) follow_link(struct path *link, struct nameidata *nd, void **p)
{ {
int error;
struct dentry *dentry = link->dentry; struct dentry *dentry = link->dentry;
int error;
char *s;
BUG_ON(nd->flags & LOOKUP_RCU); BUG_ON(nd->flags & LOOKUP_RCU);
if (link->mnt == nd->path.mnt) if (link->mnt == nd->path.mnt)
mntget(link->mnt); mntget(link->mnt);
if (unlikely(current->total_link_count >= 40)) { error = -ELOOP;
*p = ERR_PTR(-ELOOP); /* no ->put_link(), please */ if (unlikely(current->total_link_count >= 40))
path_put(&nd->path); goto out_put_nd_path;
return -ELOOP;
}
cond_resched(); cond_resched();
current->total_link_count++; current->total_link_count++;
...@@ -633,30 +633,37 @@ follow_link(struct path *link, struct nameidata *nd, void **p) ...@@ -633,30 +633,37 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
nd_set_link(nd, NULL); nd_set_link(nd, NULL);
error = security_inode_follow_link(link->dentry, nd); error = security_inode_follow_link(link->dentry, nd);
if (error) { if (error)
*p = ERR_PTR(error); /* no ->put_link(), please */ goto out_put_nd_path;
path_put(&nd->path);
return error;
}
nd->last_type = LAST_BIND; nd->last_type = LAST_BIND;
*p = dentry->d_inode->i_op->follow_link(dentry, nd); *p = dentry->d_inode->i_op->follow_link(dentry, nd);
error = PTR_ERR(*p); error = PTR_ERR(*p);
if (!IS_ERR(*p)) { if (IS_ERR(*p))
char *s = nd_get_link(nd); goto out_put_link;
error = 0;
if (s) error = 0;
error = __vfs_follow_link(nd, s); s = nd_get_link(nd);
else if (nd->last_type == LAST_BIND) { if (s) {
nd->flags |= LOOKUP_JUMPED; error = __vfs_follow_link(nd, s);
nd->inode = nd->path.dentry->d_inode; } else if (nd->last_type == LAST_BIND) {
if (nd->inode->i_op->follow_link) { nd->flags |= LOOKUP_JUMPED;
/* stepped on a _really_ weird one */ nd->inode = nd->path.dentry->d_inode;
path_put(&nd->path); if (nd->inode->i_op->follow_link) {
error = -ELOOP; /* stepped on a _really_ weird one */
} path_put(&nd->path);
error = -ELOOP;
} }
} }
if (unlikely(error))
put_link(nd, link, *p);
return error;
out_put_nd_path:
path_put(&nd->path);
out_put_link:
path_put(link);
return error; return error;
} }
...@@ -1383,9 +1390,10 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd) ...@@ -1383,9 +1390,10 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
void *cookie; void *cookie;
res = follow_link(&link, nd, &cookie); res = follow_link(&link, nd, &cookie);
if (!res) if (res)
res = walk_component(nd, path, &nd->last, break;
nd->last_type, LOOKUP_FOLLOW); res = walk_component(nd, path, &nd->last,
nd->last_type, LOOKUP_FOLLOW);
put_link(nd, &link, cookie); put_link(nd, &link, cookie);
} while (res > 0); } while (res > 0);
...@@ -1777,8 +1785,9 @@ static int path_lookupat(int dfd, const char *name, ...@@ -1777,8 +1785,9 @@ static int path_lookupat(int dfd, const char *name,
struct path link = path; struct path link = path;
nd->flags |= LOOKUP_PARENT; nd->flags |= LOOKUP_PARENT;
err = follow_link(&link, nd, &cookie); err = follow_link(&link, nd, &cookie);
if (!err) if (err)
err = lookup_last(nd, &path); break;
err = lookup_last(nd, &path);
put_link(nd, &link, cookie); put_link(nd, &link, cookie);
} }
} }
...@@ -2475,9 +2484,8 @@ static struct file *path_openat(int dfd, const char *pathname, ...@@ -2475,9 +2484,8 @@ static struct file *path_openat(int dfd, const char *pathname,
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
error = follow_link(&link, nd, &cookie); error = follow_link(&link, nd, &cookie);
if (unlikely(error)) if (unlikely(error))
filp = ERR_PTR(error); goto out_filp;
else filp = do_last(nd, &path, op, pathname);
filp = do_last(nd, &path, op, pathname);
put_link(nd, &link, cookie); put_link(nd, &link, cookie);
} }
out: out:
......
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