From a7472baba22dd5d68580f528374f93421b33667e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 4 Mar 2011 14:39:30 -0500 Subject: [PATCH] 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 --- fs/namei.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index ea14bfb04785..53bba7c1a520 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -498,8 +498,15 @@ err_root: /* 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 @@ static int link_path_walk(const char *name, struct nameidata *nd) 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 @@ last_component: (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 @@ lookup_parent: } if (!(nd->flags & LOOKUP_RCU)) path_put(&nd->path); -return_err: if (nd->flags & LOOKUP_RCU) { nd->flags &= ~LOOKUP_RCU; nd->root.mnt = NULL; -- 2.39.5