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-rw-r--r--fs/dcache.c72
1 files changed, 49 insertions, 23 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index c5dc32a59c76..bb0c4d0038db 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2270,6 +2270,48 @@ bool d_same_name(const struct dentry *dentry, const struct dentry *parent,
}
EXPORT_SYMBOL_GPL(d_same_name);
+/*
+ * This is __d_lookup_rcu() when the parent dentry has
+ * DCACHE_OP_COMPARE, which makes things much nastier.
+ */
+static noinline struct dentry *__d_lookup_rcu_op_compare(
+ const struct dentry *parent,
+ const struct qstr *name,
+ unsigned *seqp)
+{
+ u64 hashlen = name->hash_len;
+ struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
+ struct hlist_bl_node *node;
+ struct dentry *dentry;
+
+ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
+ int tlen;
+ const char *tname;
+ unsigned seq;
+
+seqretry:
+ seq = raw_seqcount_begin(&dentry->d_seq);
+ if (dentry->d_parent != parent)
+ continue;
+ if (d_unhashed(dentry))
+ continue;
+ if (dentry->d_name.hash != hashlen_hash(hashlen))
+ continue;
+ tlen = dentry->d_name.len;
+ tname = dentry->d_name.name;
+ /* we want a consistent (name,len) pair */
+ if (read_seqcount_retry(&dentry->d_seq, seq)) {
+ cpu_relax();
+ goto seqretry;
+ }
+ if (parent->d_op->d_compare(dentry, tlen, tname, name) != 0)
+ continue;
+ *seqp = seq;
+ return dentry;
+ }
+ return NULL;
+}
+
/**
* __d_lookup_rcu - search for a dentry (racy, store-free)
* @parent: parent dentry
@@ -2316,6 +2358,9 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
* Keep the two functions in sync.
*/
+ if (unlikely(parent->d_flags & DCACHE_OP_COMPARE))
+ return __d_lookup_rcu_op_compare(parent, name, seqp);
+
/*
* The hash list is protected using RCU.
*
@@ -2332,7 +2377,6 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
unsigned seq;
-seqretry:
/*
* The dentry sequence count protects us from concurrent
* renames, and thus protects parent and name fields.
@@ -2355,28 +2399,10 @@ seqretry:
continue;
if (d_unhashed(dentry))
continue;
-
- if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
- int tlen;
- const char *tname;
- if (dentry->d_name.hash != hashlen_hash(hashlen))
- continue;
- tlen = dentry->d_name.len;
- tname = dentry->d_name.name;
- /* we want a consistent (name,len) pair */
- if (read_seqcount_retry(&dentry->d_seq, seq)) {
- cpu_relax();
- goto seqretry;
- }
- if (parent->d_op->d_compare(dentry,
- tlen, tname, name) != 0)
- continue;
- } else {
- if (dentry->d_name.hash_len != hashlen)
- continue;
- if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
- continue;
- }
+ if (dentry->d_name.hash_len != hashlen)
+ continue;
+ if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0)
+ continue;
*seqp = seq;
return dentry;
}