2022-05-21 16:13:17

by Kiselev, Oleg

[permalink] [raw]
Subject: Does `-O bigalloc` still conflict with `delalloc`?

The `ext4(5)` man page, contained in the most recent e2fsprogs still says:

Warning: The bigalloc feature is still under development, and may not be fully supported
with your kernel or may have various bugs. Please see the web page http://ext4.wiki.ker‐
nel.org/index.php/Bigalloc for details. May clash with delayed allocation (see nodelal‐
loc mount option).

Is a bad interaction with `delalloc` still an issue and should we be using the `nodelalloc` option?


2022-05-28 10:10:05

by Kiselev, Oleg

[permalink] [raw]
Subject: Re: Does `-O bigalloc` still conflict with `delalloc`?

Thank you, Ted!

On 5/27/22, 7:32 PM, "Theodore Ts'o" <[email protected]> wrote:

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On Sat, May 21, 2022 at 02:39:00AM +0000, Kiselev, Oleg wrote:
> The `ext4(5)` man page, contained in the most recent e2fsprogs still says:
>
> Warning: The bigalloc feature is still under development, and may not be fully supported
> with your kernel or may have various bugs. Please see the web page http://ext4.wiki.ker‐
> nel.org/index.php/Bigalloc for details. May clash with delayed allocation (see nodelal‐
> loc mount option).
>
> Is a bad interaction with `delalloc` still an issue and should we be using the `nodelalloc` option?

Apologies for not getting back to you right away. I wanted to check
with some folks on the ext4 team, and in fact we talked about it at
this week's ext4 video chat. Eric Whitney worked on fixing bigalloc
and delalloc, and it looks like the last of the fixes landed in Linux
version 5.4 in 2019. So that warning in the ext4(5) man page is
definitely out of date.

I'll remove it in the next release of e2fsprogs.

Cheers,

- Ted

2022-05-28 12:27:23

by Theodore Ts'o

[permalink] [raw]
Subject: Re: Does `-O bigalloc` still conflict with `delalloc`?

On Sat, May 21, 2022 at 02:39:00AM +0000, Kiselev, Oleg wrote:
> The `ext4(5)` man page, contained in the most recent e2fsprogs still says:
>
> Warning: The bigalloc feature is still under development, and may not be fully supported
> with your kernel or may have various bugs. Please see the web page http://ext4.wiki.ker‐
> nel.org/index.php/Bigalloc for details. May clash with delayed allocation (see nodelal‐
> loc mount option).
>
> Is a bad interaction with `delalloc` still an issue and should we be using the `nodelalloc` option?

Apologies for not getting back to you right away. I wanted to check
with some folks on the ext4 team, and in fact we talked about it at
this week's ext4 video chat. Eric Whitney worked on fixing bigalloc
and delalloc, and it looks like the last of the fixes landed in Linux
version 5.4 in 2019. So that warning in the ext4(5) man page is
definitely out of date.

I'll remove it in the next release of e2fsprogs.

Cheers,

- Ted