lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 16 May 2018 09:00:13 +0800
From:   Liu Bo <>
To:     Eric Whitney <>
Cc:, "Theodore Y. Ts'o" <>
Subject: Re: [RFC PATCH 0/5] ext4: rework delayed allocated cluster accounting

On Mon, May 14, 2018 at 1:56 AM, Eric Whitney <> wrote:
> The goals of this patch series are to solve the specific bugs
> described in bugzilla #151491 and to arrive at a correct solution
> for delayed allocated cluster accounting for bigalloc file systems
> generally. Under some circumstances, ext4 currently makes gross
> overestimates of the number of reserved clusters required to handle
> bigalloc write requests under delayed allocation.  In addition to
> premature ENOSPC and quota limit failures, these overestimates tend
> to persist over time and in some cases even persist across umounts
> and remounts of an affected file system.
> This patch series is a work in progress.  Although it does appear to
> correct all known delayed cluster accounting deficiencies, and
> produces no regressions for all xfstest-bld test cases, it currently
> contains a significant bug that adversely affects ext4's direct I/O
> code.  The next and hopefully final step is to address that bug.
> These patches are being posted now to show the work in progress and
> to solicit comments on its general approach and implementation.
> All of the patches in the series must be applied as a unit to obtain
> a correct solution to the problem.  The individual fixes in this
> series have not been submitted separately because they can cause
> new failures or misbehavior to appear.  The effect is to make matters
> even worse for the use case described in bugzilla #151491 until all
> the fixes have been applied together.
> This patch series is based on 4.17-rc3.  4.17-rc4 has exhibited a
> number of undiagnosed xfstest-bldtest test failures that appear to be
> unrelated to ext4 and which make comparisons with a regression
> baseline troublesome.  4.17-rc3 is free of those failures.

FYI, I'm going thru the whole patch set, the first two patches look good to me.


> Eric Whitney (5):
>   ext4: fix reserved cluster accounting at delayed write time
>   ext4: reduce reserved cluster count by number of allocated clusters
>   ext4: adjust reserved cluster count when removing extents
>   ext4:  release delayed allocated clusters when removing block ranges
>   ext4: don't release delalloc clusters when invalidating page
>  fs/ext4/ext4.h           |  11 +
>  fs/ext4/extents.c        | 661 ++++++++++++++++++++++++++++-------------------
>  fs/ext4/extents_status.c | 303 ++++++++++++++++++++++
>  fs/ext4/extents_status.h |  20 ++
>  fs/ext4/inode.c          | 113 ++++----
>  fs/ext4/mballoc.c        |  11 +-
>  6 files changed, 798 insertions(+), 321 deletions(-)
> --
> 2.11.0

Powered by blists - more mailing lists