Re: [PATCH 17/25] ext4: support large block size in ext4_block_write_begin()

[Jan Kara <jack@suse.cz>]

On Sat 25-10-25 11:22:13, libaokun@huaweicloud.com wrote:
> From: Baokun Li <libaokun1@huawei.com>
> 
> Use the EXT4_P_TO_LBLK() macro to convert folio indexes to blocks to avoid
> negative left shifts after supporting blocksize greater than PAGE_SIZE.
> 
> Signed-off-by: Baokun Li <libaokun1@huawei.com>
> Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

Looks good. Feel free to add:

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

								Honza

> ---
>  fs/ext4/inode.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 73c1da90b604..d97ce88d6e0a 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -1162,8 +1162,7 @@ int ext4_block_write_begin(handle_t *handle, struct folio *folio,
>  	unsigned block_start, block_end;
>  	sector_t block;
>  	int err = 0;
> -	unsigned blocksize = inode->i_sb->s_blocksize;
> -	unsigned bbits;
> +	unsigned int blocksize = i_blocksize(inode);
>  	struct buffer_head *bh, *head, *wait[2];
>  	int nr_wait = 0;
>  	int i;
> @@ -1172,12 +1171,12 @@ int ext4_block_write_begin(handle_t *handle, struct folio *folio,
>  	BUG_ON(!folio_test_locked(folio));
>  	BUG_ON(to > folio_size(folio));
>  	BUG_ON(from > to);
> +	WARN_ON_ONCE(blocksize > folio_size(folio));
>  
>  	head = folio_buffers(folio);
>  	if (!head)
>  		head = create_empty_buffers(folio, blocksize, 0);
> -	bbits = ilog2(blocksize);
> -	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
> +	block = EXT4_P_TO_LBLK(inode, folio->index);
>  
>  	for (bh = head, block_start = 0; bh != head || !block_start;
>  	    block++, block_start = block_end, bh = bh->b_this_page) {
> -- 
> 2.46.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR