Re: [PATCH 13/19] xfs: factor out a helper to calculate the end_fsb

From: Allison Collins <allison.henderson@oracle.com>
To: Christoph Hellwig <hch@lst.de>,
	Goldwyn Rodrigues <rgoldwyn@suse.com>,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 13/19] xfs: factor out a helper to calculate the end_fsb
Date: Fri, 13 Sep 2019 17:42:37 -0700	[thread overview]
Message-ID: <a7926d72-bbee-eb3d-124d-ebcb094de6ea@oracle.com> (raw)
In-Reply-To: <20190909182722.16783-14-hch@lst.de>

Looks Ok to me:
Reviewed-by: Allison Collins <allison.henderson@oracle.com>

On 9/9/19 11:27 AM, Christoph Hellwig wrote:
> We have lots of places that want to calculate the final fsb for
> a offset + count in bytes and check that the result fits into
> s_maxbytes.  Factor out a helper for that.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/xfs/xfs_iomap.c | 40 ++++++++++++++++++++--------------------
>   1 file changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index d12eacdc9bba..0ba67a8d8169 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -102,6 +102,17 @@ xfs_hole_to_iomap(
>   	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
>   }
>   
> +static inline xfs_fileoff_t
> +xfs_iomap_end_fsb(
> +	struct xfs_mount	*mp,
> +	loff_t			offset,
> +	loff_t			count)
> +{
> +	ASSERT(offset <= mp->m_super->s_maxbytes);
> +	return min(XFS_B_TO_FSB(mp, offset + count),
> +		   XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
> +}
> +
>   xfs_extlen_t
>   xfs_eof_alignment(
>   	struct xfs_inode	*ip,
> @@ -172,8 +183,8 @@ xfs_iomap_write_direct(
>   	int		nmaps)
>   {
>   	xfs_mount_t	*mp = ip->i_mount;
> -	xfs_fileoff_t	offset_fsb;
> -	xfs_fileoff_t	last_fsb;
> +	xfs_fileoff_t	offset_fsb = XFS_B_TO_FSBT(mp, offset);
> +	xfs_fileoff_t	last_fsb = xfs_iomap_end_fsb(mp, offset, count);
>   	xfs_filblks_t	count_fsb, resaligned;
>   	xfs_extlen_t	extsz;
>   	int		nimaps;
> @@ -192,8 +203,6 @@ xfs_iomap_write_direct(
>   
>   	ASSERT(xfs_isilocked(ip, lockmode));
>   
> -	offset_fsb = XFS_B_TO_FSBT(mp, offset);
> -	last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
>   	if ((offset + count) > XFS_ISIZE(ip)) {
>   		/*
>   		 * Assert that the in-core extent list is present since this can
> @@ -533,9 +542,7 @@ xfs_file_iomap_begin_delay(
>   	struct xfs_inode	*ip = XFS_I(inode);
>   	struct xfs_mount	*mp = ip->i_mount;
>   	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
> -	xfs_fileoff_t		maxbytes_fsb =
> -		XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
> -	xfs_fileoff_t		end_fsb;
> +	xfs_fileoff_t		end_fsb = xfs_iomap_end_fsb(mp, offset, count);
>   	struct xfs_bmbt_irec	imap, cmap;
>   	struct xfs_iext_cursor	icur, ccur;
>   	xfs_fsblock_t		prealloc_blocks = 0;
> @@ -565,8 +572,6 @@ xfs_file_iomap_begin_delay(
>   			goto out_unlock;
>   	}
>   
> -	end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);
> -
>   	/*
>   	 * Search the data fork fork first to look up our source mapping.  We
>   	 * always need the data fork map, as we have to return it to the
> @@ -648,7 +653,7 @@ xfs_file_iomap_begin_delay(
>   		 * the lower level functions are updated.
>   		 */
>   		count = min_t(loff_t, count, 1024 * PAGE_SIZE);
> -		end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);
> +		end_fsb = xfs_iomap_end_fsb(mp, offset, count);
>   
>   		if (xfs_is_always_cow_inode(ip))
>   			whichfork = XFS_COW_FORK;
> @@ -674,7 +679,8 @@ xfs_file_iomap_begin_delay(
>   			if (align)
>   				p_end_fsb = roundup_64(p_end_fsb, align);
>   
> -			p_end_fsb = min(p_end_fsb, maxbytes_fsb);
> +			p_end_fsb = min(p_end_fsb,
> +				XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
>   			ASSERT(p_end_fsb > offset_fsb);
>   			prealloc_blocks = p_end_fsb - end_fsb;
>   		}
> @@ -937,7 +943,8 @@ xfs_file_iomap_begin(
>   	struct xfs_inode	*ip = XFS_I(inode);
>   	struct xfs_mount	*mp = ip->i_mount;
>   	struct xfs_bmbt_irec	imap, cmap;
> -	xfs_fileoff_t		offset_fsb, end_fsb;
> +	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
> +	xfs_fileoff_t		end_fsb = xfs_iomap_end_fsb(mp, offset, length);
>   	int			nimaps = 1, error = 0;
>   	bool			shared = false;
>   	u16			iomap_flags = 0;
> @@ -963,12 +970,6 @@ xfs_file_iomap_begin(
>   	if (error)
>   		return error;
>   
> -	ASSERT(offset <= mp->m_super->s_maxbytes);
> -	if (offset > mp->m_super->s_maxbytes - length)
> -		length = mp->m_super->s_maxbytes - offset;
> -	offset_fsb = XFS_B_TO_FSBT(mp, offset);
> -	end_fsb = XFS_B_TO_FSB(mp, offset + length);
> -
>   	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
>   			       &nimaps, 0);
>   	if (error)
> @@ -1189,8 +1190,7 @@ xfs_seek_iomap_begin(
>   		/*
>   		 * Fake a hole until the end of the file.
>   		 */
> -		data_fsb = min(XFS_B_TO_FSB(mp, offset + length),
> -			       XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
> +		data_fsb = xfs_iomap_end_fsb(mp, offset, length);
>   	}
>   
>   	/*
>