linux-ext4 - Re: [PATCH v2 2/7] ext4: introduce new metadata buffer read helpers

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Message-ID: <20201009014315.GB816148@mit.edu>
Date:   Thu, 8 Oct 2020 21:43:15 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     "zhangyi (F)" <yi.zhang@...wei.com>
Cc:     linux-ext4@...r.kernel.org, jack@...e.com, adilger.kernel@...ger.ca
Subject: Re: [PATCH v2 2/7] ext4: introduce new metadata buffer read helpers

On Thu, Sep 24, 2020 at 03:33:32PM +0800, zhangyi (F) wrote:
> The previous patch add clear_buffer_verified() before we read metadata
> block from disk again, but it's rather easy to miss clearing of this bit
> because currently we read metadata buffer through different open codes
> (e.g. ll_rw_block(), bh_submit_read() and invoke submit_bh() directly).
> So, it's time to add common helpers to unify in all the places reading
> metadata buffers instead. This patch add 3 helpers:
> 
>  - ext4_read_bh_nowait(): async read metadata buffer if it's actually
>    not uptodate, clear buffer_verified bit before read from disk.
>  - ext4_read_bh(): sync version of read metadata buffer, it will wait
>    until the read operation return and check the return status.
>  - ext4_read_bh_lock(): try to lock the buffer before read buffer, it
>    will skip reading if the buffer is already locked.
> 
> After this patch, we need to use these helpers in all the places reading
> metadata buffer instead of different open codes.
> 
> Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>
> Suggested-by: Jan Kara <jack@...e.cz>

Thanks, applied.

						- Ted