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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Josh Triplett <josh@joshtriplett.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Jan Kara <jack@suse.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-ext4@vger.kernel.org
Subject: Re: ext4 regression in v5.9-rc2 from e7bfb5c9bb3d on ro fs with overlapped bitmaps
Date: Mon, 5 Oct 2020 23:18:34 -0400	[thread overview]
Message-ID: <20201006031834.GA5797@mit.edu> (raw)
In-Reply-To: <20201006025110.GJ49559@magnolia>

On Mon, Oct 05, 2020 at 07:51:10PM -0700, Darrick J. Wong wrote:
> > > Could /somebody/ please document the ondisk format changes that are
> > > associated with this feature?
> > 
> > I pretty much had to sort it out by looking at a combination of
> > e2fsprogs and the kernel, and a lot of experimentation, until I ended up
> > with something that the kernel was completely happy with without a
> > single complaint.
> > 
> > I'd be happy to write up a summary of the format.
> 
> Seems like a good idea, particularly since you're asking for a format
> change that requires kernel support and the ondisk format documentation
> lives under Documentation/.  That said...

> > If you set up the rest of the metadata consistently with it (for
> > instance, 0 free blocks and 0 free inodes), you'll only get a single
> > complaint, from the e2fsck equivalent of block_validity. See
> > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=956509 for details on
> > that;
> 
> ...Ted shot down this whole thing six months ago.
> 
> The Debian bug database is /not/ the designated forum to discuss changes
> to the ondisk format; linux-ext4 is.

What Josh is proposing I'm pretty sure would also break "e2fsck -E
unshare_blocks", so that's another reason not to accept this as a
valid format change.

As far as I'm concerned, contrib/e2fsdroid is the canonical definition
of how to create valid file systems with shared_blocks.

					- Ted

  reply	other threads:[~2020-10-06  3:18 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAHk-=wj-H5BYCU_kKiOK=B9sN3BtRzL4pnne2AJPyf54nQ+d=w@mail.gmail.com>
2020-10-05  8:14 ` ext4 regression in v5.9-rc2 from e7bfb5c9bb3d on ro fs with overlapped bitmaps Josh Triplett
2020-10-05  9:46   ` Jan Kara
2020-10-05 10:16     ` Josh Triplett
2020-10-05 16:19       ` Jan Kara
2020-10-05 16:20   ` Jan Kara
2020-10-05 17:36   ` Darrick J. Wong
2020-10-06  0:04     ` Theodore Y. Ts'o
2020-10-06  0:32     ` Josh Triplett
2020-10-06  2:51       ` Darrick J. Wong
2020-10-06  3:18         ` Theodore Y. Ts'o [this message]
2020-10-06  5:03           ` Josh Triplett
2020-10-06  6:03             ` Josh Triplett
2020-10-06 13:35             ` Theodore Y. Ts'o
2020-10-07  8:03               ` Josh Triplett
2020-10-07 14:32                 ` Theodore Y. Ts'o
2020-10-07 20:14                   ` Josh Triplett
2020-10-08  2:10                     ` Theodore Y. Ts'o
2020-10-08 17:54                       ` Darrick J. Wong
2020-10-08 22:38                         ` Josh Triplett
2020-10-09  2:54                           ` Darrick J. Wong
2020-10-09 19:08                             ` Josh Triplett
2020-10-08 22:22                       ` Josh Triplett
2020-10-09 14:37                         ` Theodore Y. Ts'o
2020-10-09 20:30                           ` Josh Triplett
2021-01-10 18:41                           ` Malicious fs images was " Pavel Machek
2021-01-11 18:51                             ` Darrick J. Wong
2021-01-11 19:39                               ` Eric Biggers
2021-01-12 21:43                             ` Theodore Ts'o
2021-01-12 22:28                               ` Pavel Machek
2021-01-13  5:09                                 ` Theodore Ts'o
2020-10-08  2:57                     ` Andreas Dilger
2020-10-08 19:12                       ` Josh Triplett
2020-10-08 19:25                         ` Andreas Dilger
2020-10-08 22:28                           ` Josh Triplett

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