Al Viro:
> Nope. You are misreading it. Note that in *all* cases the parent is
> locked. And NULL is returned exactly in the case when that parent is
:::
Thanks.
Please allow me another question.
In the case of concurrent dentry_kill() and shrink_dentry_list(),
dentry_kill() kills the dentry and calls list_del(&dentry->d_u.d_child).
lock_parent() (called by shrink_dentry_list()) doesn't check d_child
nor DCACHE_DENTRY_KILLED. So shrink_dentry_list() may get a parent of a
dead dentry and tries traversing via d_parent.
Is it correct to track d_parent after list_del(&dentry->d_u.d_child)?
Should lock_parent() consider DCACHE_DENTRY_KILLED too?
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -533,7 +533,8 @@ failed:
static inline struct dentry *lock_parent(struct dentry *dentry)
{
struct dentry *parent = dentry->d_parent;
- if (IS_ROOT(dentry))
+ if (IS_ROOT(dentry)
+ || (dentry->d_flags & DCACHE_DENTRY_KILLED))
return NULL;
if (likely(spin_trylock(&parent->d_lock)))
return parent;
J. R. Okajima
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