From: Josef Bacik <josef@toxicpanda.com>
To: Nikolay Borisov <nborisov@suse.com>,
linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 2/8] btrfs: do not init a reloc root if we aren't relocating
Date: Wed, 4 Mar 2020 13:47:12 -0500 [thread overview]
Message-ID: <1af0b245-d1b6-a043-f74c-e3d80c08590e@toxicpanda.com> (raw)
In-Reply-To: <27cd0745-6e4c-be69-5604-00b36a3cfcd7@suse.com>
On 3/4/20 1:44 PM, Nikolay Borisov wrote:
>
>
> On 4.03.20 г. 18:18 ч., Josef Bacik wrote:
>> We previously were checking if the root had a dead root before accessing
>> root->reloc_root in order to avoid a UAF type bug. However this
>> scenario happens after we've unset the reloc control, so we would have
>> been saved if we'd simply checked for fs_info->reloc_control. At this
>> point during relocation we no longer need to be creating new reloc
>> roots, so simply move this check above the reloc_root checks to avoid
>> any future races and confusion.
>>
>> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
>
>
> Doesn't this patch essentially obviate the reloc_root_is_dead. W.r.t
> ->reloc_ctl it's important to note that it's being set under reloc_mutex
> which this function is also called under so we are guaranteed consistent
> value.
>
Yes it does, but I want to keep the cleanups separate from the fixes. I threw
this in here because it's more of a correctness/fix than a cleanup. Thanks,
Josef
next prev parent reply other threads:[~2020-03-04 18:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 16:18 [PATCH 0/8][v2] relocation error handling fixes Josef Bacik
2020-03-04 16:18 ` [PATCH 1/8] btrfs: drop block from cache on error in relocation Josef Bacik
2020-03-05 11:37 ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 2/8] btrfs: do not init a reloc root if we aren't relocating Josef Bacik
2020-03-04 18:44 ` Nikolay Borisov
2020-03-04 18:47 ` Josef Bacik [this message]
2020-03-05 11:24 ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 3/8] btrfs: unset reloc control if we fail to recover Josef Bacik
2020-03-05 11:38 ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 4/8] btrfs: free the reloc_control in a consistent way Josef Bacik
2020-03-05 11:39 ` Qu Wenruo
2020-03-13 15:18 ` David Sterba
2020-03-13 15:32 ` Josef Bacik
2020-03-14 0:13 ` Qu Wenruo
2020-03-04 16:18 ` [PATCH 5/8] btrfs: run clean_dirty_subvols if we fail to start a trans Josef Bacik
2020-03-05 11:40 ` Qu Wenruo
2020-03-05 17:46 ` David Sterba
2020-03-04 16:18 ` [PATCH 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root Josef Bacik
2020-03-05 11:41 ` Qu Wenruo
2020-03-05 13:54 ` Josef Bacik
2020-03-04 16:18 ` [PATCH 7/8] btrfs: hold a ref on the root->reloc_root Josef Bacik
2020-03-04 16:18 ` [PATCH 8/8] btrfs: remove a BUG_ON() from merge_reloc_roots() Josef Bacik
2020-03-13 14:35 ` [PATCH 0/8][v2] relocation error handling fixes David Sterba
2020-03-13 15:44 [PATCH 0/8][v3] " Josef Bacik
2020-03-13 15:44 ` [PATCH 2/8] btrfs: do not init a reloc root if we aren't relocating Josef Bacik
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