[PATCH v2] jbd2: fix potential double free

[Chengguang Xu]

When fail from creating cache jbd2_inode_cache, we will
destroy previously created cache jbd2_handle_cache twice.
This patch fixes it by sperating each cache
initialization/destruction to individual function.

Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxx>
---
v2:
- Seperate cache initialization/destruction to individual function.

 fs/jbd2/journal.c     | 51 +++++++++++++++++++++++++++----------------
 fs/jbd2/revoke.c      | 32 +++++++++++++++++----------
 fs/jbd2/transaction.c |  8 ++++---
 include/linux/jbd2.h  |  8 ++++---
 4 files changed, 62 insertions(+), 37 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 37e16d969925..0f1ac43d0560 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2299,7 +2299,7 @@ static void jbd2_journal_destroy_slabs(void)
 	}
 }
 
-static int jbd2_journal_create_slab(size_t size)
+static int __init jbd2_journal_create_slab(size_t size)
 {
 	static DEFINE_MUTEX(jbd2_slab_create_mutex);
 	int i = order_base_2(size) - 10;
@@ -2375,22 +2375,19 @@ static struct kmem_cache *jbd2_journal_head_cache;
 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
 #endif
 
-static int jbd2_journal_init_journal_head_cache(void)
+static int __init jbd2_journal_init_journal_head_cache(void)
 {
-	int retval;
-
-	J_ASSERT(jbd2_journal_head_cache == NULL);
+	J_ASSERT(!jbd2_journal_head_cache);
 	jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
 				sizeof(struct journal_head),
 				0,		/* offset */
 				SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
 				NULL);		/* ctor */
-	retval = 0;
 	if (!jbd2_journal_head_cache) {
-		retval = -ENOMEM;
 		printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
+		return -ENOMEM;
 	}
-	return retval;
+	return 0;
 }
 
 static void jbd2_journal_destroy_journal_head_cache(void)
@@ -2636,28 +2633,38 @@ static void __exit jbd2_remove_jbd_stats_proc_entry(void)
 
 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
 
+static int __init jbd2_journal_init_inode_cache(void)
+{
+	J_ASSERT(!jbd2_inode_cache);
+	jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
+	if (!jbd2_inode_cache) {
+		pr_emerg("JBD2: failed to create inode cache\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
 static int __init jbd2_journal_init_handle_cache(void)
 {
+	J_ASSERT(!jbd2_handle_cache);
 	jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
-	if (jbd2_handle_cache == NULL) {
+	if (!jbd2_handle_cache) {
 		printk(KERN_EMERG "JBD2: failed to create handle cache\n");
 		return -ENOMEM;
 	}
-	jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
-	if (jbd2_inode_cache == NULL) {
-		printk(KERN_EMERG "JBD2: failed to create inode cache\n");
-		kmem_cache_destroy(jbd2_handle_cache);
-		return -ENOMEM;
-	}
 	return 0;
 }
 
+static void jbd2_journal_destroy_inode_cache(void)
+{
+	kmem_cache_destroy(jbd2_inode_cache);
+	jbd2_inode_cache = NULL;
+}
+
 static void jbd2_journal_destroy_handle_cache(void)
 {
 	kmem_cache_destroy(jbd2_handle_cache);
 	jbd2_handle_cache = NULL;
-	kmem_cache_destroy(jbd2_inode_cache);
-	jbd2_inode_cache = NULL;
 }
 
 /*
@@ -2668,11 +2675,15 @@ static int __init journal_init_caches(void)
 {
 	int ret;
 
-	ret = jbd2_journal_init_revoke_caches();
+	ret = jbd2_journal_init_revoke_record_cache();
+	if (ret == 0)
+		ret = jbd2_journal_init_revoke_table_cache();
 	if (ret == 0)
 		ret = jbd2_journal_init_journal_head_cache();
 	if (ret == 0)
 		ret = jbd2_journal_init_handle_cache();
+	if (ret == 0)
+		ret = jbd2_journal_init_inode_cache();
 	if (ret == 0)
 		ret = jbd2_journal_init_transaction_cache();
 	return ret;
@@ -2680,9 +2691,11 @@ static int __init journal_init_caches(void)
 
 static void jbd2_journal_destroy_caches(void)
 {
-	jbd2_journal_destroy_revoke_caches();
+	jbd2_journal_destroy_revoke_record_cache();
+	jbd2_journal_destroy_revoke_table_cache();
 	jbd2_journal_destroy_journal_head_cache();
 	jbd2_journal_destroy_handle_cache();
+	jbd2_journal_destroy_inode_cache();
 	jbd2_journal_destroy_transaction_cache();
 	jbd2_journal_destroy_slabs();
 }
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index a1143e57a718..69b9bc329964 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -178,33 +178,41 @@ static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
 	return NULL;
 }
 
-void jbd2_journal_destroy_revoke_caches(void)
+void jbd2_journal_destroy_revoke_record_cache(void)
 {
 	kmem_cache_destroy(jbd2_revoke_record_cache);
 	jbd2_revoke_record_cache = NULL;
+}
+
+void jbd2_journal_destroy_revoke_table_cache(void)
+{
 	kmem_cache_destroy(jbd2_revoke_table_cache);
 	jbd2_revoke_table_cache = NULL;
 }
 
-int __init jbd2_journal_init_revoke_caches(void)
+int __init jbd2_journal_init_revoke_record_cache(void)
 {
 	J_ASSERT(!jbd2_revoke_record_cache);
-	J_ASSERT(!jbd2_revoke_table_cache);
-
 	jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
 					SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
-	if (!jbd2_revoke_record_cache)
-		goto record_cache_failure;
 
+	if (!jbd2_revoke_record_cache) {
+		pr_emerg("JBD2: failed to create revoke_record cache\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+int __init jbd2_journal_init_revoke_table_cache(void)
+{
+	J_ASSERT(!jbd2_revoke_table_cache);
 	jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
 					     SLAB_TEMPORARY);
-	if (!jbd2_revoke_table_cache)
-		goto table_cache_failure;
-	return 0;
-table_cache_failure:
-	jbd2_journal_destroy_revoke_caches();
-record_cache_failure:
+	if (!jbd2_revoke_table_cache) {
+		pr_emerg("JBD2: failed to create revoke_table cache\n");
 		return -ENOMEM;
+	}
+	return 0;
 }
 
 static struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index f940d31c2adc..8ca4fddc705f 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -42,9 +42,11 @@ int __init jbd2_journal_init_transaction_cache(void)
 					0,
 					SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
 					NULL);
-	if (transaction_cache)
-		return 0;
-	return -ENOMEM;
+	if (!transaction_cache) {
+		pr_emerg("JBD2: failed to create transaction cache\n");
+		return -ENOMEM;
+	}
+	return 0;
 }
 
 void jbd2_journal_destroy_transaction_cache(void)
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index c2ffff5f9ae2..6c9870e16b19 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1318,7 +1318,7 @@ extern void		__wait_on_journal (journal_t *);
 
 /* Transaction cache support */
 extern void jbd2_journal_destroy_transaction_cache(void);
-extern int  jbd2_journal_init_transaction_cache(void);
+extern int __init jbd2_journal_init_transaction_cache(void);
 extern void jbd2_journal_free_transaction(transaction_t *);
 
 /*
@@ -1446,8 +1446,10 @@ static inline void jbd2_free_inode(struct jbd2_inode *jinode)
 /* Primary revoke support */
 #define JOURNAL_REVOKE_DEFAULT_HASH 256
 extern int	   jbd2_journal_init_revoke(journal_t *, int);
-extern void	   jbd2_journal_destroy_revoke_caches(void);
-extern int	   jbd2_journal_init_revoke_caches(void);
+extern void	   jbd2_journal_destroy_revoke_record_cache(void);
+extern void	   jbd2_journal_destroy_revoke_table_cache(void);
+extern int __init jbd2_journal_init_revoke_record_cache(void);
+extern int __init jbd2_journal_init_revoke_table_cache(void);
 
 extern void	   jbd2_journal_destroy_revoke(journal_t *);
 extern int	   jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *);
-- 
2.20.1