| From: Al Viro <viro@zeniv.linux.org.uk> |
| Date: Fri, 23 Feb 2018 22:07:35 -0500 |
| Subject: [PATCH 02/17] now lock_parent() can't run into killed dentry |
| |
| Upstream commit 65d8eb5a8f5480756105173de147ef5d60163e2f |
| |
| all remaining callers hold either a reference or ->i_lock |
| |
| Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| fs/dcache.c | 13 +++---------- |
| 1 file changed, 3 insertions(+), 10 deletions(-) |
| |
| --- a/fs/dcache.c |
| +++ b/fs/dcache.c |
| @@ -593,8 +593,6 @@ static inline struct dentry *lock_parent |
| 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 @@ static inline struct dentry *lock_parent |
| 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; |
| } |
| |
