make nameidata_dentry_drop_rcu_maybe() always leave RCU mode
Now we have do_follow_link() guaranteed to leave without dangling RCU
and the next step will get LOOKUP_RCU logics completely out of
link_path_walk().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index ea14bfb..53bba7c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -498,8 +498,15 @@
/* Try to drop out of rcu-walk mode if we were in it, otherwise do nothing. */
static inline int nameidata_dentry_drop_rcu_maybe(struct nameidata *nd, struct dentry *dentry)
{
- if (nd->flags & LOOKUP_RCU)
- return nameidata_dentry_drop_rcu(nd, dentry);
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(nameidata_dentry_drop_rcu(nd, dentry))) {
+ nd->flags &= ~LOOKUP_RCU;
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ return -ECHILD;
+ }
+ }
return 0;
}
@@ -1424,7 +1431,7 @@
if (inode && inode->i_op->follow_link) {
err = do_follow_link(inode, &next, nd);
if (err)
- goto return_err;
+ return err;
nd->inode = nd->path.dentry->d_inode;
} else {
path_to_nameidata(&next, nd);
@@ -1455,7 +1462,7 @@
(lookup_flags & LOOKUP_FOLLOW)) {
err = do_follow_link(inode, &next, nd);
if (err)
- goto return_err;
+ return err;
nd->inode = nd->path.dentry->d_inode;
} else {
path_to_nameidata(&next, nd);
@@ -1477,7 +1484,6 @@
}
if (!(nd->flags & LOOKUP_RCU))
path_put(&nd->path);
-return_err:
if (nd->flags & LOOKUP_RCU) {
nd->flags &= ~LOOKUP_RCU;
nd->root.mnt = NULL;