jbd2: fix potential double free

When failing from creating cache jbd2_inode_cache, we will destroy the
previously created cache jbd2_handle_cache twice. This patch fixes
this by moving each cache initialization/destruction to its own
separate, individual function.

Signed-off-by: Chengguang Xu <[e-mail]>
Signed-off-by: Theodore Ts'o <[e-mail]>
Cc: [e-mail]

fs/jbd2/journal.c

···
 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)
···
 
 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
 
-static int __init jbd2_journal_init_handle_cache(void)
+static int __init jbd2_journal_init_inode_cache(void)
 {
-	jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
-	if (jbd2_handle_cache == NULL) {
-		printk(KERN_EMERG "JBD2: failed to create handle cache\n");
-		return -ENOMEM;
-	}
+	J_ASSERT(!jbd2_inode_cache);
 	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);
+	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) {
+		printk(KERN_EMERG "JBD2: failed to create handle cache\n");
+		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;
 }
 
 /*
···
 {
 	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;
···
 
 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();
 }

fs/jbd2/revoke.c

···
 	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)

fs/jbd2/transaction.c

···
 					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)

include/linux/jbd2.h

···
 
 /* 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 *);
 
 /*
···
 /* 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 *);