jffs2: fix memory leak in jffs2_do_mount_fs

If jffs2_build_filesystem() in jffs2_do_mount_fs() returns an error,
we can observe the following kmemleak report:

--------------------------------------------
unreferenced object 0xffff88811b25a640 (size 64):
comm "mount", pid 691, jiffies 4294957728 (age 71.952s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffffa493be24>] kmem_cache_alloc_trace+0x584/0x880
[<ffffffffa5423a06>] jffs2_sum_init+0x86/0x130
[<ffffffffa5400e58>] jffs2_do_mount_fs+0x798/0xac0
[<ffffffffa540acf3>] jffs2_do_fill_super+0x383/0xc30
[<ffffffffa540c00a>] jffs2_fill_super+0x2ea/0x4c0
[...]
unreferenced object 0xffff88812c760000 (size 65536):
comm "mount", pid 691, jiffies 4294957728 (age 71.952s)
hex dump (first 32 bytes):
bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................
bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................
backtrace:
[<ffffffffa493a449>] __kmalloc+0x6b9/0x910
[<ffffffffa5423a57>] jffs2_sum_init+0xd7/0x130
[<ffffffffa5400e58>] jffs2_do_mount_fs+0x798/0xac0
[<ffffffffa540acf3>] jffs2_do_fill_super+0x383/0xc30
[<ffffffffa540c00a>] jffs2_fill_super+0x2ea/0x4c0
[...]
--------------------------------------------

This is because the resources allocated in jffs2_sum_init() are not
released. Call jffs2_sum_exit() to release these resources to solve
the problem.

Fixes: e631ddba5887 ("[JFFS2] Add erase block summary support (mount time improvement)")
Cc: [e-mail]
Signed-off-by: Baokun Li <[e-mail]>
Signed-off-by: Richard Weinberger <[e-mail]>

fs/jffs2/build.c

···
 		jffs2_free_ino_caches(c);
 		jffs2_free_raw_node_refs(c);
 		ret = -EIO;
-		goto out_free;
+		goto out_sum_exit;
 	}
 
 	jffs2_calc_trigger_levels(c);
 
 	return 0;
 
+ out_sum_exit:
+	jffs2_sum_exit(c);
  out_free:
 	kvfree(c->blocks);