From: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
To: unlisted-recipients:; (no To-header on input)
Cc: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>,
Jan Kara <jack@suse.cz>, "Theodore Ts'o" <tytso@mit.edu>,
Jan Kara <jack@suse.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] Updated locking documentation for transaction_t
Date: Wed, 17 Mar 2021 21:58:12 +0100 [thread overview]
Message-ID: <c309db05-bca5-7bcd-cf86-a85637d49407@tu-dortmund.de> (raw)
In-Reply-To: <20210211171410.17984-1-alexander.lochmann@tu-dortmund.de>
Does this patch look good to you either?
- Alex
On 11.02.21 18:14, Alexander Lochmann wrote:
> Some members of transaction_t are allowed to be read without
> any lock being held if accessed from the correct context.
> We used LockDoc's findings to determine those members.
> Each member of them is marked with a short comment:
> "no lock needed for jbd2 thread".
>
> Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de>
> Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de>
> Reviewed-by: Jan Kara <jack@suse.cz>
> ---
> include/linux/jbd2.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index 99d3cd051ac3..1f19d19f6435 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -594,18 +594,18 @@ struct transaction_s
> */
> unsigned long t_log_start;
>
> - /* Number of buffers on the t_buffers list [j_list_lock] */
> + /* Number of buffers on the t_buffers list [j_list_lock, no locks needed for jbd2 thread] */
> int t_nr_buffers;
>
> /*
> * Doubly-linked circular list of all buffers reserved but not yet
> - * modified by this transaction [j_list_lock]
> + * modified by this transaction [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_reserved_list;
>
> /*
> * Doubly-linked circular list of all metadata buffers owned by this
> - * transaction [j_list_lock]
> + * transaction [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_buffers;
>
> @@ -631,7 +631,7 @@ struct transaction_s
> /*
> * Doubly-linked circular list of metadata buffers being shadowed by log
> * IO. The IO buffers on the iobuf list and the shadow buffers on this
> - * list match each other one for one at all times. [j_list_lock]
> + * list match each other one for one at all times. [j_list_lock, no locks needed for jbd2 thread]
> */
> struct journal_head *t_shadow_list;
>
>
--
Technische Universität Dortmund
Alexander Lochmann PGP key: 0xBC3EF6FD
Otto-Hahn-Str. 16 phone: +49.231.7556141
D-44227 Dortmund fax: +49.231.7556116
http://ess.cs.tu-dortmund.de/Staff/al
next prev parent reply other threads:[~2021-03-17 20:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 17:14 [PATCH v3] Updated locking documentation for transaction_t Alexander Lochmann
2021-03-17 20:58 ` Alexander Lochmann [this message]
2021-04-02 15:40 ` Theodore Ts'o
-- strict thread matches above, loose matches on Subject: below --
2019-04-08 8:35 Alexander Lochmann
2019-06-20 20:45 ` Alexander Lochmann
2020-10-15 13:26 ` Alexander Lochmann
2020-12-03 14:04 ` Theodore Y. Ts'o
2020-12-03 14:38 ` Alexander Lochmann
2020-12-03 20:39 ` Theodore Y. Ts'o
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