Re: file born 30 seconds after its creation on ext4 - bug?

From	<tomas@tuxteam.de>
Newsgroups	linux.debian.user
Subject	Re: file born 30 seconds after its creation on ext4 - bug?
Date	2022-04-30 15:10 +0200
Message-ID	<EhV1f-cdXu-5@gated-at.bofh.it> (permalink)
References	<EhNZL-c9Hi-1@gated-at.bofh.it> <EhQNX-cbmK-1@gated-at.bofh.it> <EhUyd-cdxO-5@gated-at.bofh.it>
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On Sat, Apr 30, 2022 at 12:31:07PM -0000, Curt wrote:
> On 2022-04-30, Thomas Schmitt <scdbackup@gmx.net> wrote:
> >
> > Indeed. With normal filesystem operations there should be no need to call
> > something like sync(2) in order to get a consistent representation of the
> > current filesystem state.
> >
> 
> What does the following mean, then, in that light:
> 
>  Because of delayed allocation and other performance optimizations, ext4's
>  behavior of writing files to disk is different from ext3. In ext4, when a
>  program writes to the file system, it is not guaranteed to be on-disk unless
>  the program issues an fsync() call afterwards. 

You still can't observe that during a normally running system. You'll
see the same file system behaviour regardless of whether the data have
touched the disk or are still in cache.

The only way to actually observe this in action is to "pull the plug"
before data has a chance to reach the disk. Then, of course, some
files you thought were there will have magically disappeared.

Cheers
-- 
t

Thread

file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-26 15:50 +0200
  Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-26 19:10 +0200
    Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 04:40 +0200
      Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-27 09:10 +0200
        Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 10:30 +0200
          Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-27 11:40 +0200
            Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 15:20 +0200
              Re: file born 30 seconds after its creation on ext4 - bug? Greg Wooledge <greg@wooledge.org> - 2022-04-27 15:30 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 16:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Stefan Monnier <monnier@iro.umontreal.ca> - 2022-04-28 04:50 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Greg Wooledge <greg@wooledge.org> - 2022-04-28 05:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? duh <fill_in_the_blanks@email.com> - 2022-04-29 16:20 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Marc Auslander <marcausl@gmail.com> - 2022-04-29 20:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? "sp007@caiway.net" <sp007@caiway.net> - 2022-04-29 22:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? <tomas@tuxteam.de> - 2022-04-30 07:40 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-30 10:40 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? <tomas@tuxteam.de> - 2022-04-30 14:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-05-02 01:20 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? <tomas@tuxteam.de> - 2022-05-02 07:30 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Curt <curty@free.fr> - 2022-04-30 14:40 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? <tomas@tuxteam.de> - 2022-04-30 15:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-30 15:20 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-05-02 01:40 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Greg Wooledge <greg@wooledge.org> - 2022-05-02 01:40 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? David Wright <deblis@lionunicorn.co.uk> - 2022-05-02 17:10 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? <tomas@tuxteam.de> - 2022-05-02 18:20 +0200
                Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-28 10:40 +0200
            Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-28 11:40 +0200
  Re: file born 30 seconds after its creation on ext4 - bug? Nicholas Geovanis <nickgeovanis@gmail.com> - 2022-04-26 19:40 +0200
    Re: file born 30 seconds after its creation on ext4 - bug? Nicholas Geovanis <nickgeovanis@gmail.com> - 2022-04-26 19:50 +0200
      Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 04:50 +0200
  Re: file born 30 seconds after its creation on ext4 - bug? Stefan Monnier <monnier@iro.umontreal.ca> - 2022-04-26 20:20 +0200
    Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-27 05:10 +0200
  Re: file born 30 seconds after its creation on ext4 - bug? "Thomas Schmitt" <scdbackup@gmx.net> - 2022-04-28 11:30 +0200
    Re: file born 30 seconds after its creation on ext4 - bug? Vincent Lefevre <vincent@vinc17.net> - 2022-04-28 12:20 +0200

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