linux-kernel - Re: [PATCH 2/5] ext4: correct the reserved credits for extent conversion

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Message-ID: <2xgxxvibw35ijwl5gtuure7hegce6h3ysx2m453hx6hcs5vnqs@2tvvv57fbvee>
Date: Thu, 5 Jun 2025 13:32:12 +0200
From: Jan Kara <jack@...e.cz>
To: Zhang Yi <yi.zhang@...weicloud.com>
Cc: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz, 
	ojaswin@...ux.ibm.com, yi.zhang@...wei.com, libaokun1@...wei.com, yukuai3@...wei.com, 
	yangerkun@...wei.com
Subject: Re: [PATCH 2/5] ext4: correct the reserved credits for extent
 conversion

On Fri 30-05-25 14:28:55, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@...wei.com>
> 
> Now, we reserve journal credits for converting extents in only one page
> to written state when the I/O operation is complete. This is
> insufficient when large folio is enabled.
> 
> Fix this by reserving credits for converting up to one extent per block in
> the largest 2MB folio, this calculation should only involve extents index
> and leaf blocks, so it should not estimate too many credits.
> 
> Fixes: 7ac67301e82f ("ext4: enable large folio for regular file")
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/inode.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 5ef34c0c5633..d35c07c1dcac 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2808,12 +2808,12 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)
>  	mpd->journalled_more_data = 0;
>  
>  	if (ext4_should_dioread_nolock(inode)) {
> +		int bpf = ext4_journal_blocks_per_folio(inode);
>  		/*
>  		 * We may need to convert up to one extent per block in
> -		 * the page and we may dirty the inode.
> +		 * the folio and we may dirty the inode.
>  		 */
> -		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
> -						PAGE_SIZE >> inode->i_blkbits);
> +		rsv_blocks = 1 + ext4_ext_index_trans_blocks(inode, bpf);
>  	}
>  
>  	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> -- 
> 2.46.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR