1 files changed, 96 insertions, 16 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 9fcec07a9d7c..72c4c347afb7 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -497,7 +497,7 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval)
 
 	spin_lock(&inode_hash_lock);
 	spin_lock(&inode->i_lock);
-	hlist_add_head(&inode->i_hash, b);
+	hlist_add_head_rcu(&inode->i_hash, b);
 	spin_unlock(&inode->i_lock);
 	spin_unlock(&inode_hash_lock);
 }
@@ -513,7 +513,7 @@ void __remove_inode_hash(struct inode *inode)
 {
 	spin_lock(&inode_hash_lock);
 	spin_lock(&inode->i_lock);
-	hlist_del_init(&inode->i_hash);
+	hlist_del_init_rcu(&inode->i_hash);
 	spin_unlock(&inode->i_lock);
 	spin_unlock(&inode_hash_lock);
 }
@@ -1107,7 +1107,7 @@ again:
 	 */
 	spin_lock(&inode->i_lock);
 	inode->i_state |= I_NEW;
-	hlist_add_head(&inode->i_hash, head);
+	hlist_add_head_rcu(&inode->i_hash, head);
 	spin_unlock(&inode->i_lock);
 	if (!creating)
 		inode_sb_list_add(inode);
@@ -1201,7 +1201,7 @@ again:
 			inode->i_ino = ino;
 			spin_lock(&inode->i_lock);
 			inode->i_state = I_NEW;
-			hlist_add_head(&inode->i_hash, head);
+			hlist_add_head_rcu(&inode->i_hash, head);
 			spin_unlock(&inode->i_lock);
 			inode_sb_list_add(inode);
 			spin_unlock(&inode_hash_lock);
@@ -1244,15 +1244,10 @@ static int test_inode_iunique(struct super_block *sb, unsigned long ino)
 	struct hlist_head *b = inode_hashtable + hash(sb, ino);
 	struct inode *inode;
 
-	spin_lock(&inode_hash_lock);
-	hlist_for_each_entry(inode, b, i_hash) {
-		if (inode->i_ino == ino && inode->i_sb == sb) {
-			spin_unlock(&inode_hash_lock);
+	hlist_for_each_entry_rcu(inode, b, i_hash) {
+		if (inode->i_ino == ino && inode->i_sb == sb)
 			return 0;
-		}
 	}
-	spin_unlock(&inode_hash_lock);
-
 	return 1;
 }
 
@@ -1281,6 +1276,7 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
 	static unsigned int counter;
 	ino_t res;
 
+	rcu_read_lock();
 	spin_lock(&iunique_lock);
 	do {
 		if (counter <= max_reserved)
@@ -1288,6 +1284,7 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
 		res = counter++;
 	} while (!test_inode_iunique(sb, res));
 	spin_unlock(&iunique_lock);
+	rcu_read_unlock();
 
 	return res;
 }
@@ -1456,6 +1453,84 @@ out:
 }
 EXPORT_SYMBOL(find_inode_nowait);
 
+/**
+ * find_inode_rcu - find an inode in the inode cache
+ * @sb:		Super block of file system to search
+ * @hashval:	Key to hash
+ * @test:	Function to test match on an inode
+ * @data:	Data for test function
+ *
+ * Search for the inode specified by @hashval and @data in the inode cache,
+ * where the helper function @test will return 0 if the inode does not match
+ * and 1 if it does.  The @test function must be responsible for taking the
+ * i_lock spin_lock and checking i_state for an inode being freed or being
+ * initialized.
+ *
+ * If successful, this will return the inode for which the @test function
+ * returned 1 and NULL otherwise.
+ *
+ * The @test function is not permitted to take a ref on any inode presented.
+ * It is also not permitted to sleep.
+ *
+ * The caller must hold the RCU read lock.
+ */
+struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
+			     int (*test)(struct inode *, void *), void *data)
+{
+	struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+	struct inode *inode;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
+			 "suspicious find_inode_rcu() usage");
+
+	hlist_for_each_entry_rcu(inode, head, i_hash) {
+		if (inode->i_sb == sb &&
+		    !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) &&
+		    test(inode, data))
+			return inode;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(find_inode_rcu);
+
+/**
+ * find_inode_by_rcu - Find an inode in the inode cache
+ * @sb:		Super block of file system to search
+ * @ino:	The inode number to match
+ *
+ * Search for the inode specified by @hashval and @data in the inode cache,
+ * where the helper function @test will return 0 if the inode does not match
+ * and 1 if it does.  The @test function must be responsible for taking the
+ * i_lock spin_lock and checking i_state for an inode being freed or being
+ * initialized.
+ *
+ * If successful, this will return the inode for which the @test function
+ * returned 1 and NULL otherwise.
+ *
+ * The @test function is not permitted to take a ref on any inode presented.
+ * It is also not permitted to sleep.
+ *
+ * The caller must hold the RCU read lock.
+ */
+struct inode *find_inode_by_ino_rcu(struct super_block *sb,
+				    unsigned long ino)
+{
+	struct hlist_head *head = inode_hashtable + hash(sb, ino);
+	struct inode *inode;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
+			 "suspicious find_inode_by_ino_rcu() usage");
+
+	hlist_for_each_entry_rcu(inode, head, i_hash) {
+		if (inode->i_ino == ino &&
+		    inode->i_sb == sb &&
+		    !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)))
+		    return inode;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(find_inode_by_ino_rcu);
+
 int insert_inode_locked(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
@@ -1480,7 +1555,7 @@ int insert_inode_locked(struct inode *inode)
 		if (likely(!old)) {
 			spin_lock(&inode->i_lock);
 			inode->i_state |= I_NEW | I_CREATING;
-			hlist_add_head(&inode->i_hash, head);
+			hlist_add_head_rcu(&inode->i_hash, head);
 			spin_unlock(&inode->i_lock);
 			spin_unlock(&inode_hash_lock);
 			return 0;
@@ -1540,6 +1615,7 @@ static void iput_final(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
 	const struct super_operations *op = inode->i_sb->s_op;
+	unsigned long state;
 	int drop;
 
 	WARN_ON(inode->i_state & I_NEW);
@@ -1555,16 +1631,20 @@ static void iput_final(struct inode *inode)
 		return;
 	}
 
+	state = inode->i_state;
 	if (!drop) {
-		inode->i_state |= I_WILL_FREE;
+		WRITE_ONCE(inode->i_state, state | I_WILL_FREE);
 		spin_unlock(&inode->i_lock);
+
 		write_inode_now(inode, 1);
+
 		spin_lock(&inode->i_lock);
-		WARN_ON(inode->i_state & I_NEW);
-		inode->i_state &= ~I_WILL_FREE;
+		state = inode->i_state;
+		WARN_ON(state & I_NEW);
+		state &= ~I_WILL_FREE;
 	}
 
-	inode->i_state |= I_FREEING;
+	WRITE_ONCE(inode->i_state, state | I_FREEING);
 	if (!list_empty(&inode->i_lru))
 		inode_lru_list_del(inode);
 	spin_unlock(&inode->i_lock);