From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE,T_DKIMWL_WL_MED, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 4B6C17D922 for ; Thu, 30 May 2019 00:53:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727226AbfE3AxY (ORCPT ); Wed, 29 May 2019 20:53:24 -0400 Received: from mail-yw1-f74.google.com ([209.85.161.74]:52557 "EHLO mail-yw1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727223AbfE3AxY (ORCPT ); Wed, 29 May 2019 20:53:24 -0400 Received: by mail-yw1-f74.google.com with SMTP id b189so3886654ywa.19 for ; Wed, 29 May 2019 17:53:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=d6X4/k5B5WeQgyIvpn8Af86NqovFLF22qTA1Y2V4Fe8=; b=Ax2EXMsdAnoEHIrqzhP0Cv23VlEaDoSoO1OWqhvxtcuBXmnYYLbiiBAZQlVXUUtGgA i6w+G4d54N8mfV0D6KY3vURUd55d8xA1pwqYEpTzjK68EmxEOCRJVDhq648b4GXT1jGV 3YrMacqCMm6wtkWM9ach4dG7xfETTseNfVw9UM/pxIHth0Ji7tonp1P9tLbqoqqtynbi DiENSJNzIdEipIykCMGLgC1Nz8YKxon3Gno9T6HkP2TBj6bY9GFxNm0etPi64anLqTnl aFpqLIUEQL5Pswsuq9dgOrW+1PKzioUiwtMYbgzR/a96OB4IOOCPkunrKKKeoQnMXWxu 4Y7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=d6X4/k5B5WeQgyIvpn8Af86NqovFLF22qTA1Y2V4Fe8=; b=dbbfIpTjbNa8L1pcY3wnh0GraxGRy8s9g1KG7XiYr8m5jObdeUJ4uQV9spHNcgeG0w AlWLtMXocS0hH9kyM1/s7+vI9XlUHSe3xilWL6yu73TskfTMuUmTwVL5Vl2pdx+60DnP 4ynOl5UNXLRG5sxFSvqTn0N4XLOh4sLTyheeZTBezsmAaSb8eUT/+XVBja8ctV1+eU2N PkO1HdxJKYtlC2BSobLMTWQMOYmVTHY6VihGpndRnor3d9bdYCfylnMhyyCb24II+hps SmSt2QDOpH37v7da/GwfU0okG1+hWNCGbrvVnRcl+p37dgC7s+W5/foWGmtPK8rdqQpL Z1EA== X-Gm-Message-State: APjAAAUbd6v58IUtzbLi+ogF7Y4nTZyNOhJ9+ctbDJXc5O3jNRkD7Wbe l1Ph68sTA6FWCdUSGTOaBvwfv9/fpgc= X-Google-Smtp-Source: APXvYqzY+oI/v3047+rLfAdqlDZ9Z79kMZvQRPmWfGPVRdyfWVyQ3mLlfGRyfTAwrOQom+6CDZKVd7elYDo= X-Received: by 2002:a81:300c:: with SMTP id w12mr555304yww.57.1559177603199; Wed, 29 May 2019 17:53:23 -0700 (PDT) Date: Wed, 29 May 2019 17:49:04 -0700 In-Reply-To: <20190530004906.261170-1-drosen@google.com> Message-Id: <20190530004906.261170-3-drosen@google.com> Mime-Version: 1.0 References: <20190530004906.261170-1-drosen@google.com> X-Mailer: git-send-email 2.22.0.rc1.257.g3120a18244-goog Subject: [PATCH v3 2/4] f2fs: Fix root reserved on remount From: Daniel Rosenberg To: Jaegeuk Kim , Chao Yu , Jonathan Corbet , linux-f2fs-devel@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg Content-Type: text/plain; charset="UTF-8" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On a remount, you can currently set root reserved if it was not previously set. This can cause an underflow if reserved has been set to a very high value, since then root reserved + current reserved could be greater than user_block_count. inc_valid_block_count later subtracts out these values from user_block_count, causing an underflow. Signed-off-by: Daniel Rosenberg --- fs/f2fs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 912e2619d581b..359fd68509d16 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -213,7 +213,8 @@ void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...) static inline void limit_reserve_root(struct f2fs_sb_info *sbi) { - block_t limit = (sbi->user_block_count << 1) / 1000; + block_t limit = min((sbi->user_block_count << 1) / 1000, + sbi->user_block_count - sbi->reserved_blocks); /* limit is 0.2% */ if (test_opt(sbi, RESERVE_ROOT) && -- 2.22.0.rc1.257.g3120a18244-goog