1 files changed, 54 insertions, 35 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index c5dc32a59c76..52e6d5fdab6b 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;
 	}
@@ -2571,15 +2597,7 @@ EXPORT_SYMBOL(d_rehash);
 
 static inline unsigned start_dir_add(struct inode *dir)
 {
-	/*
-	 * The caller holds a spinlock (dentry::d_lock). On !PREEMPT_RT
-	 * kernels spin_lock() implicitly disables preemption, but not on
-	 * PREEMPT_RT.  So for RT it has to be done explicitly to protect
-	 * the sequence count write side critical section against a reader
-	 * or another writer preempting, which would result in a live lock.
-	 */
-	if (IS_ENABLED(CONFIG_PREEMPT_RT))
-		preempt_disable();
+	preempt_disable_nested();
 	for (;;) {
 		unsigned n = dir->i_dir_seq;
 		if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
@@ -2592,8 +2610,7 @@ static inline void end_dir_add(struct inode *dir, unsigned int n,
 			       wait_queue_head_t *d_wait)
 {
 	smp_store_release(&dir->i_dir_seq, n + 2);
-	if (IS_ENABLED(CONFIG_PREEMPT_RT))
-		preempt_enable();
+	preempt_enable_nested();
 	wake_up_all(d_wait);
 }
 
@@ -3232,8 +3249,10 @@ void d_genocide(struct dentry *parent)
 
 EXPORT_SYMBOL(d_genocide);
 
-void d_tmpfile(struct dentry *dentry, struct inode *inode)
+void d_tmpfile(struct file *file, struct inode *inode)
 {
+	struct dentry *dentry = file->f_path.dentry;
+
 	inode_dec_link_count(inode);
 	BUG_ON(dentry->d_name.name != dentry->d_iname ||
 		!hlist_unhashed(&dentry->d_u.d_alias) ||