From 65d8eb5a8f5480756105173de147ef5d60163e2f Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 23 Feb 2018 22:07:35 -0500
Subject: [PATCH] now lock_parent() can't run into killed dentry
all remaining callers hold either a reference or ->i_lock
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/dcache.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index af8501489af59..916fd57b9d18d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -593,8 +593,6 @@ static inline struct dentry *lock_parent(struct dentry *dentry)
struct dentry *parent = dentry->d_parent;
if (IS_ROOT(dentry))
return NULL;
- if (unlikely(dentry->d_lockref.count < 0))
- return NULL;
if (likely(spin_trylock(&parent->d_lock)))
return parent;
rcu_read_lock();
@@ -614,16 +612,11 @@ again:
spin_unlock(&parent->d_lock);
goto again;
}
- if (parent != dentry) {
+ rcu_read_unlock();
+ if (parent != dentry)
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
- if (unlikely(dentry->d_lockref.count < 0)) {
- spin_unlock(&parent->d_lock);
- parent = NULL;
- }
- } else {
+ else
parent = NULL;
- }
- rcu_read_unlock();
return parent;
}
--
2.30.2