From: Chris Murphy <lists@colorremedies.com>
To: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: Does GRUB btrfs support log tree?
Date: Fri, 25 Oct 2019 11:50:36 +0200 [thread overview]
Message-ID: <CAJCQCtTWF2e6Q1MNLDVkmq62N6zv8n-BGEvT1c9vzK=TtN93FA@mail.gmail.com> (raw)
In-Reply-To: <CAJCQCtS1v7waFA=ERafSCSCHmPJVytdFZkJLqNTC3U3Gw3Y7tA@mail.gmail.com>
On Fri, Oct 25, 2019 at 11:47 AM Chris Murphy <lists@colorremedies.com> wrote:
>
> I see references to root and chunk trees, but not the log tree.
>
> If boot related files: kernel, initramfs, bootloader configuration
> files, are stored on Btrfs; and if they are changed in such a way as
> to rely on the log tree; and then there's a crash; what's the worse
> case scenario effect?
>
> At first glance, if the bootloader doesn't support log tree, it would
> have a stale view of the file system. Since log tree writes means a
> full file system update hasn't happened, the old file system state
> hasn't been dereferenced, so even in an SSD + discard case, the system
> should still be bootable. And at that point Btrfs kernel code does log
> replay, and catches the system up, and the next update will boot the
> new state.
>
> Correct?
Pretty sure this is the current and self-contained Btrfs code for GRUB
http://git.savannah.gnu.org/cgit/grub.git/tree/grub-core/fs/btrfs.c
--
Chris Murphy
next prev parent reply other threads:[~2019-10-25 9:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 9:47 Does GRUB btrfs support log tree? Chris Murphy
2019-10-25 9:50 ` Chris Murphy [this message]
2019-10-26 7:12 ` Andrei Borzenkov
2019-10-27 20:05 ` Chris Murphy
2019-11-04 19:34 ` David Sterba
2019-11-11 19:37 ` Chris Murphy
2019-11-12 20:04 ` Goffredo Baroncelli
2019-11-13 17:00 ` Chris Murphy
2019-11-13 18:54 ` Goffredo Baroncelli
2019-11-13 21:50 ` Chris Murphy
2019-11-14 8:18 ` Andrei Borzenkov
2019-11-17 23:24 ` Chris Murphy
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