diff options
| -rw-r--r-- | fs/dcache.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index b949af850cd..2d244227999 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -611,8 +611,23 @@ static inline void __dget(struct dentry *dentry) struct dentry *dget_parent(struct dentry *dentry) { + int gotref; struct dentry *ret; + /* + * Do optimistic parent lookup without any + * locking. + */ + rcu_read_lock(); + ret = ACCESS_ONCE(dentry->d_parent); + gotref = lockref_get_not_zero(&ret->d_lockref); + rcu_read_unlock(); + if (likely(gotref)) { + if (likely(ret == ACCESS_ONCE(dentry->d_parent))) + return ret; + dput(ret); + } + repeat: /* * Don't need rcu_dereference because we re-check it was correct under |