jbd2: don't leak memory if setting up journal fails

In journal_init_common(), if we failed to allocate the j_wbuf array, or
if we failed to create the buffer_head for the journal superblock, we
leaked the memory allocated for the revocation tables.  Fix this.

Cc: stable@vger.kernel.org # 4.9
Fixes: f0c9fd5458bacf7b12a9a579a727dc740cbe047e
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

fs/jbd2/journal.c

@@ -1125,10 +1125,8 @@ static journal_t *journal_init_common(struct block_device *bdev,
 
 	/* Set up a default-sized revoke table for the new mount. */
 	err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
-	if (err) {
-		kfree(journal);
-		return NULL;
-	}
+	if (err)
+		goto err_cleanup;
 
 	spin_lock_init(&journal->j_history_lock);
 
@@ -1145,23 +1143,25 @@ static journal_t *journal_init_common(struct block_device *bdev,
 	journal->j_wbufsize = n;
 	journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
 					GFP_KERNEL);
-	if (!journal->j_wbuf) {
-		kfree(journal);
-		return NULL;
-	}
+	if (!journal->j_wbuf)
+		goto err_cleanup;
 
 	bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
 	if (!bh) {
 		pr_err("%s: Cannot get buffer for journal superblock\n",
 			__func__);
-		kfree(journal->j_wbuf);
-		kfree(journal);
-		return NULL;
+		goto err_cleanup;
 	}
 	journal->j_sb_buffer = bh;
 	journal->j_superblock = (journal_superblock_t *)bh->b_data;
 
 	return journal;
+
+err_cleanup:
+	kfree(journal->j_wbuf);
+	jbd2_journal_destroy_revoke(journal);
+	kfree(journal);
+	return NULL;
 }
 
 /* jbd2_journal_init_dev and jbd2_journal_init_inode:

fs/jbd2/revoke.c

@@ -280,6 +280,7 @@ int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
 
 fail1:
 	jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
+	journal->j_revoke_table[0] = NULL;
 fail0:
 	return -ENOMEM;
 }