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linux-sg2042
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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>
This commit is contained in:
Al Viro 2018-02-23 22:07:35 -05:00
parent 3b3f09f48b
commit 65d8eb5a8f
1 changed files with 4 additions and 11 deletions
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15
fs/dcache.c
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@ -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) {
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 {
parent = NULL;
}
rcu_read_unlock();
if (parent != dentry)
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
else
parent = NULL;
return parent;
}