From: Stefan Behrens <sbehrens@giantdisaster.de>
To: Wang Shilong <wangshilong1991@gmail.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] Btrfs: fix race condition between writting and scrubing supers
Date: Sat, 19 Oct 2013 10:50:43 +0200 [thread overview]
Message-ID: <526247E3.9000804@giantdisaster.de> (raw)
In-Reply-To: <1382156250-2336-1-git-send-email-wangshilong1991@gmail.com>
On 10/19/2013 06:17, Wang Shilong wrote:
> From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
>
> Scrubing supers is not in a transaction context, when trying to
> write supers to disk, we should check if we are trying to
> scrub supers.Fix it.
>
> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
> ---
> fs/btrfs/disk-io.c | 2 ++
> fs/btrfs/transaction.c | 2 ++
> 2 files changed, 4 insertions(+)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 419968e..0debb19 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -3582,7 +3582,9 @@ int btrfs_commit_super(struct btrfs_root *root)
> return ret;
> }
>
> + btrfs_scrub_pause_super(root);
> ret = write_ctree_super(NULL, root, 0);
> + btrfs_scrub_continue_super(root);
> return ret;
> }
>
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 277fe81..3ebcbbd 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1892,7 +1892,9 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
> goto cleanup_transaction;
> }
>
> + btrfs_scrub_pause_super(root);
> ret = write_ctree_super(trans, root, 0);
> + btrfs_scrub_continue_super(root);
> if (ret) {
> mutex_unlock(&root->fs_info->tree_log_mutex);
> goto cleanup_transaction;
>
What kind of race do you see between writing the 4K superblock and scrub
checking its checksum? Or in other words, what could happen?
next prev parent reply other threads:[~2013-10-19 8:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-19 4:17 [PATCH] Btrfs: fix race condition between writting and scrubing supers Wang Shilong
2013-10-19 8:50 ` Stefan Behrens [this message]
2013-10-19 10:32 ` Shilong Wang
2013-10-19 14:03 ` Stefan Behrens
2013-10-19 14:34 ` Wang Shilong
2013-10-20 4:03 ` Wang Shilong
2013-10-22 8:37 ` Stefan Behrens
2013-10-22 16:55 ` Bob Marley
2013-10-23 17:21 ` Stefan Behrens
2013-10-24 10:08 ` Chris Mason
2013-10-24 10:42 ` Miao Xie
2013-10-24 11:32 ` Wang Shilong
2013-10-25 2:14 ` Miao Xie
2013-10-20 7:28 ` Bob Marley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=526247E3.9000804@giantdisaster.de \
--to=sbehrens@giantdisaster.de \
--cc=linux-btrfs@vger.kernel.org \
--cc=wangshilong1991@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).