From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: Josef Bacik <josef@toxicpanda.com>,
linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root
Date: Thu, 5 Mar 2020 19:41:28 +0800 [thread overview]
Message-ID: <21e4b656-af48-d10c-c549-11770eba541a@gmx.com> (raw)
In-Reply-To: <20200304161830.2360-7-josef@toxicpanda.com>
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On 2020/3/5 上午12:18, Josef Bacik wrote:
> We were doing the clear dance for the reloc root after doing the drop of
> the reloc root, which means we have a giant window where we could miss
> having BTRFS_ROOT_DEAD_RELOC_TREE unset and the reloc_root == NULL.
Still, I can't see the problem where we have BTRFS_ROOT_DEAD_RELOC_TREE
and reloc_root == NULL.
IMHO, that would cause anything wrong. Or is there anything I missed?
Thanks,
Qu
>
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
> fs/btrfs/relocation.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 53509c367eff..ceb90d152cdd 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -2291,18 +2291,19 @@ static int clean_dirty_subvols(struct reloc_control *rc)
>
> list_del_init(&root->reloc_dirty_list);
> root->reloc_root = NULL;
> - if (reloc_root) {
> -
> - ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
> - if (ret2 < 0 && !ret)
> - ret = ret2;
> - }
> /*
> * Need barrier to ensure clear_bit() only happens after
> * root->reloc_root = NULL. Pairs with have_reloc_root.
> */
> smp_wmb();
> clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
> +
> + if (reloc_root) {
> +
> + ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
> + if (ret2 < 0 && !ret)
> + ret = ret2;
> + }
> btrfs_put_root(root);
> } else {
> /* Orphan reloc tree, just clean it up */
>
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next prev parent reply other threads:[~2020-03-05 11:41 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
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 [this message]
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 6/8] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root Josef Bacik
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