[PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[Wang Sheng-Hui]

The patch is against 3.0

In the definition of struct journal_head, the comment for
the field "unsigned b_cow_tid" says the field tracks the
last transaction id in which this buffer has been cowed.

In the header part of file journal-head.h, it defines
   typedef unsigned int  tid_t;
We should use type tid_t to define transaction id fields.

Change the field "b_cow_tid" of struct journal_head from
type unsigned to tid_t.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
---
 include/linux/journal-head.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/journal-head.h b/include/linux/journal-head.h
index 44e95d0..423cb6d 100644
--- a/include/linux/journal-head.h
+++ b/include/linux/journal-head.h
@@ -45,7 +45,7 @@ struct journal_head {
 	 * has been cowed
 	 * [jbd_lock_bh_state()]
 	 */
-	unsigned b_cow_tid;
+	tid_t b_cow_tid;
 
 	/*
 	 * Copy of the buffer data frozen for writing to the log.
-- 
1.7.1

Re: [PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[Amir Goldstein]

On Mon, Jul 25, 2011 at 4:02 PM, Wang Sheng-Hui <shhuiw@gmail.com> wrote:
> The patch is against 3.0
>
> In the definition of struct journal_head, the comment for
> the field "unsigned b_cow_tid" says the field tracks the
> last transaction id in which this buffer has been cowed.
>
> In the header part of file journal-head.h, it defines
>   typedef unsigned int  tid_t;
> We should use type tid_t to define transaction id fields.
>
> Change the field "b_cow_tid" of struct journal_head from
> type unsigned to tid_t.
>
> Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>

my bad.

Acked-by: Amir Goldstein <amir73il@users.sf.net>

> ---
>  include/linux/journal-head.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/journal-head.h b/include/linux/journal-head.h
> index 44e95d0..423cb6d 100644
> --- a/include/linux/journal-head.h
> +++ b/include/linux/journal-head.h
> @@ -45,7 +45,7 @@ struct journal_head {
>         * has been cowed
>         * [jbd_lock_bh_state()]
>         */
> -       unsigned b_cow_tid;
> +       tid_t b_cow_tid;
>
>        /*
>         * Copy of the buffer data frozen for writing to the log.
> --
> 1.7.1
>
> --
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Re: [PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[Christoph Hellwig]

On Mon, Jul 25, 2011 at 09:02:25PM +0800, Wang Sheng-Hui wrote:
> The patch is against 3.0
> 
> In the definition of struct journal_head, the comment for
> the field "unsigned b_cow_tid" says the field tracks the
> last transaction id in which this buffer has been cowed.

The correct fix is to simply remove the field, as it's entirely unused.

Re: [PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[Amir Goldstein]

On Mon, Jul 25, 2011 at 4:44 PM, Christoph Hellwig <hch@infradead.org> wrote:
> On Mon, Jul 25, 2011 at 09:02:25PM +0800, Wang Sheng-Hui wrote:
>> The patch is against 3.0
>>
>> In the definition of struct journal_head, the comment for
>> the field "unsigned b_cow_tid" says the field tracks the
>> last transaction id in which this buffer has been cowed.
>
> The correct fix is to simply remove the field, as it's entirely unused.
>

It's part of the ext4 snapshot patches, which are making their way into mainline
as slowly as one could expect them to.
This patch was merged for 2.6.39, so more users will be able to test
ext4 snapshots
independent module without having to patch their kernels, so that the
patches get proper
QA before they arrive to mainline.

Cheers,
Amir.

Re: [PATCH] jbd: change the field "b_cow_tid" of struct journal_head from type unsigned to tid_t

[Jan Kara]

On Mon 25-07-11 21:02:25, Wang Sheng-Hui wrote:
> The patch is against 3.0
> 
> In the definition of struct journal_head, the comment for
> the field "unsigned b_cow_tid" says the field tracks the
> last transaction id in which this buffer has been cowed.
> 
> In the header part of file journal-head.h, it defines
>    typedef unsigned int  tid_t;
> We should use type tid_t to define transaction id fields.
> 
> Change the field "b_cow_tid" of struct journal_head from
> type unsigned to tid_t.
  Hmm, I didn't notice Ted merged this from ext4cow patch series. Looking
at struct journal_head, I'm thinking we might split jbd and jbd2 version of
this structure. jbd one could be 16 bytes shorter. Anyway, I've merged your
patch. Thanks.

								Honza
> 
> Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
> ---
>  include/linux/journal-head.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/include/linux/journal-head.h b/include/linux/journal-head.h
> index 44e95d0..423cb6d 100644
> --- a/include/linux/journal-head.h
> +++ b/include/linux/journal-head.h
> @@ -45,7 +45,7 @@ struct journal_head {
>  	 * has been cowed
>  	 * [jbd_lock_bh_state()]
>  	 */
> -	unsigned b_cow_tid;
> +	tid_t b_cow_tid;
>  
>  	/*
>  	 * Copy of the buffer data frozen for writing to the log.
> -- 
> 1.7.1
> 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR