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Date: Thu, 13 Jun 2024 22:56:52 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Zhang Yi <yi.zhang@huaweicloud.com>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, djwong@kernel.org, hch@infradead.org,
	brauner@kernel.org, david@fromorbit.com, chandanbabu@kernel.org,
	jack@suse.cz, yi.zhang@huawei.com, chengzhihao1@huawei.com,
	yukuai3@huawei.com
Subject: Re: [PATCH -next v5 2/8] iomap: pass blocksize to
 iomap_truncate_page()
Message-ID: <ZmvbpFjEkYguGHha@infradead.org>
References: <20240613090033.2246907-1-yi.zhang@huaweicloud.com>
 <20240613090033.2246907-3-yi.zhang@huaweicloud.com>
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In-Reply-To: <20240613090033.2246907-3-yi.zhang@huaweicloud.com>

On Thu, Jun 13, 2024 at 05:00:27PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> iomap_truncate_page() always assumes the block size of the truncating
> inode is i_blocksize(), this is not always true for some filesystems,
> e.g. XFS does extent size alignment for realtime inodes. Drop this
> assumption and pass the block size for zeroing into
> iomap_truncate_page(), allow filesystems to indicate the correct block
> size.

FYI, I still prefer to just kill iomap_truncate_page in it's current
form instead.

>  #include "../internal.h"
> @@ -1453,11 +1454,10 @@ iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
>  EXPORT_SYMBOL_GPL(iomap_zero_range);
>  
>  int
> -iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
> -		const struct iomap_ops *ops)
> +iomap_truncate_page(struct inode *inode, loff_t pos, unsigned int blocksize,
> +		bool *did_zero, const struct iomap_ops *ops)
>  {
> -	unsigned int blocksize = i_blocksize(inode);
> -	unsigned int off = pos & (blocksize - 1);
> +	unsigned int off = rem_u64(pos, blocksize);
>  
>  	/* Block boundary? Nothing to do */
>  	if (!off)
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 378342673925..32306804b01b 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -1471,10 +1471,11 @@ xfs_truncate_page(
>  	bool			*did_zero)
>  {
>  	struct inode		*inode = VFS_I(ip);
> +	unsigned int		blocksize = i_blocksize(inode);
>  
>  	if (IS_DAX(inode))
>  		return dax_truncate_page(inode, pos, did_zero,
>  					&xfs_dax_write_iomap_ops);
> -	return iomap_truncate_page(inode, pos, did_zero,
> +	return iomap_truncate_page(inode, pos, blocksize, did_zero,
>  				   &xfs_buffered_write_iomap_ops);
>  }
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 6fc1c858013d..d67bf86ec582 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -273,8 +273,8 @@ int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
>  		const struct iomap_ops *ops);
>  int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
>  		bool *did_zero, const struct iomap_ops *ops);
> -int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
> -		const struct iomap_ops *ops);
> +int iomap_truncate_page(struct inode *inode, loff_t pos, unsigned int blocksize,
> +		bool *did_zero, const struct iomap_ops *ops);
>  vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
>  			const struct iomap_ops *ops);
>  int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> -- 
> 2.39.2
> 
> 
---end quoted text---