jbd2: fix kabi broken in struct journal_s

hulk inclusion
category: bugfix
bugzilla: 172974
CVE: NA
---------------------------

72c9e4df ('jbd2: ensure abort the journal if detect IO error when
writing original buffer back') will add 'j_atomic_flags' which can lead
lots of kabi broken like jbd2_journal_destroy/jbd2_journal_abort and so
on.

Fix it by add a wrapper.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

fs/jbd2/checkpoint.c

@@ -562,6 +562,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 	struct transaction_chp_stats_s *stats;
 	transaction_t *transaction;
 	journal_t *journal;
+	journal_wrapper_t *journal_wrapper;
 	struct buffer_head *bh = jh2bh(jh);
 
 	JBUFFER_TRACE(jh, "entry");
@@ -572,6 +573,8 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 		return 0;
 	}
 	journal = transaction->t_journal;
+	journal_wrapper = container_of(journal, journal_wrapper_t,
+				       jw_journal);
 
 	JBUFFER_TRACE(jh, "removing from transaction");
 
@@ -583,7 +586,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 	 * journal here and we abort the journal later from a better context.
 	 */
 	if (buffer_write_io_error(bh))
-		set_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags);
+		set_bit(JBD2_CHECKPOINT_IO_ERROR, &journal_wrapper->j_atomic_flags);
 
 	__buffer_unlink(jh);
 	jh->b_cp_transaction = NULL;

fs/jbd2/journal.c

@@ -1129,14 +1129,17 @@ static journal_t *journal_init_common(struct block_device *bdev,
 {
 	static struct lock_class_key jbd2_trans_commit_key;
 	journal_t *journal;
+	journal_wrapper_t *journal_wrapper;
 	int err;
 	struct buffer_head *bh;
 	int n;
 
-	journal = kzalloc(sizeof(*journal), GFP_KERNEL);
-	if (!journal)
+	journal_wrapper = kzalloc(sizeof(*journal_wrapper), GFP_KERNEL);
+	if (!journal_wrapper)
 		return NULL;
 
+	journal = &(journal_wrapper->jw_journal);
+
 	init_waitqueue_head(&journal->j_wait_transaction_locked);
 	init_waitqueue_head(&journal->j_wait_done_commit);
 	init_waitqueue_head(&journal->j_wait_commit);
@@ -1195,7 +1198,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
 err_cleanup:
 	kfree(journal->j_wbuf);
 	jbd2_journal_destroy_revoke(journal);
-	kfree(journal);
+	kfree(journal_wrapper);
 	return NULL;
 }
 
@@ -1425,11 +1428,13 @@ int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
 				     unsigned long tail_block, int write_op)
 {
 	journal_superblock_t *sb = journal->j_superblock;
+	journal_wrapper_t *journal_wrapper = container_of(journal,
+					     journal_wrapper_t, jw_journal);
 	int ret;
 
 	if (is_journal_aborted(journal))
 		return -EIO;
-	if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags)) {
+	if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal_wrapper->j_atomic_flags)) {
 		jbd2_journal_abort(journal, -EIO);
 		return -EIO;
 	}
@@ -1754,6 +1759,8 @@ int jbd2_journal_load(journal_t *journal)
 int jbd2_journal_destroy(journal_t *journal)
 {
 	int err = 0;
+	journal_wrapper_t *journal_wrapper = container_of(journal,
+					     journal_wrapper_t, jw_journal);
 
 	/* Wait for the commit thread to wake up and die. */
 	journal_kill_thread(journal);
@@ -1795,7 +1802,7 @@ int jbd2_journal_destroy(journal_t *journal)
 	 * may become inconsistent.
 	 */
 	if (!is_journal_aborted(journal) &&
-	    test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags))
+	    test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal_wrapper->j_atomic_flags))
 		jbd2_journal_abort(journal, -EIO);
 
 	if (journal->j_sb_buffer) {
@@ -1823,7 +1830,7 @@ int jbd2_journal_destroy(journal_t *journal)
 	if (journal->j_chksum_driver)
 		crypto_free_shash(journal->j_chksum_driver);
 	kfree(journal->j_wbuf);
-	kfree(journal);
+	kfree(journal_wrapper);
 
 	return err;
 }

include/linux/jbd2.h

@@ -105,6 +105,8 @@ typedef struct jbd2_journal_handle handle_t;	/* Atomic operation type */
  * This is an opaque datatype.
  **/
 typedef struct journal_s	journal_t;	/* Journal control structure */
+
+typedef struct journal_wrapper_s journal_wrapper_t;
 #endif
 
 /*
@@ -780,11 +782,6 @@ struct journal_s
 	 */
 	unsigned long		j_flags;
 
-	/**
-	 * @j_atomic_flags: Atomic journaling state flags.
-	 */
-	unsigned long		j_atomic_flags;
-
 	/**
 	 * @j_errno:
 	 *
@@ -1199,6 +1196,22 @@ struct journal_s
 #endif
 };
 
+/**
+ * struct journal_wrapper_s - The wrapper of journal_s to fix KABI.
+ */
+struct journal_wrapper_s
+{
+	/**
+	 * @jw_journal: real journal.
+	 */
+	journal_t		jw_journal;
+
+	/**
+	 * @j_atomic_flags: Atomic journaling state flags.
+	 */
+	unsigned long		j_atomic_flags;
+};
+
 #define jbd2_might_wait_for_commit(j) \
 	do { \
 		rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \