[PATCH 16/20] VFS/namei: enable RCU-walk when following symlinks.

NeilBrown
2015-03-23T02:39:41Z

Now that follow_link handles LOOKUP_RCU, we do not need to
'unlazy_walk' when a symlink is found.

As we remain in RCU-walk mode, dentry->d_inode can change
so the BUG_ON() assertions are no longer appropriate.

Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/namei.c | 21 +++------------------
1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 40ff4cb04244..0f5b627bd78e 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1636,16 +1636,9 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
if (!inode || d_is_negative(path->dentry))
goto out_path_put;

- if (should_follow_link(path->dentry, follow)) {
- if (nd->flags & LOOKUP_RCU) {
- if (unlikely(unlazy_walk(nd, path->dentry))) {
- err = -ECHILD;
- goto out_err;
- }
- }
- BUG_ON(inode != path->dentry->d_inode);
+ if (should_follow_link(path->dentry, follow))
return 1;
- }
+
path_to_nameidata(path, nd);
nd->inode = inode;
return 0;
@@ -3102,16 +3095,8 @@ finish_lookup:
goto out;
}

- if (should_follow_link(path->dentry, !symlink_ok)) {
- if (nd->flags & LOOKUP_RCU) {
- if (unlikely(unlazy_walk(nd, path->dentry))) {
- error = -ECHILD;
- goto out;
- }
- }
- BUG_ON(inode != path->dentry->d_inode);
+ if (should_follow_link(path->dentry, !symlink_ok))
return 1;
- }

if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
path_to_nameidata(path, nd);