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Date: Fri, 26 Apr 2024 08:16:19 -0700
From: "Darrick J. Wong" <djwong@kernel.org>
To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
Cc: willy@infradead.org, brauner@kernel.org, david@fromorbit.com,
	chandan.babu@oracle.com, akpm@linux-foundation.org,
	linux-fsdevel@vger.kernel.org, hare@suse.de,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-xfs@vger.kernel.org, mcgrof@kernel.org, gost.dev@samsung.com,
	p.raghav@samsung.com
Subject: Re: [PATCH v4 10/11] xfs: make the calculation generic in
 xfs_sb_validate_fsb_count()
Message-ID: <20240426151619.GF360919@frogsfrogsfrogs>
References: <20240425113746.335530-1-kernel@pankajraghav.com>
 <20240425113746.335530-11-kernel@pankajraghav.com>
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In-Reply-To: <20240425113746.335530-11-kernel@pankajraghav.com>

On Thu, Apr 25, 2024 at 01:37:45PM +0200, Pankaj Raghav (Samsung) wrote:
> From: Pankaj Raghav <p.raghav@samsung.com>
> 
> Instead of assuming that PAGE_SHIFT is always higher than the blocklog,
> make the calculation generic so that page cache count can be calculated
> correctly for LBS.
> 
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>

Looks ok,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_mount.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index df370eb5dc15..56d71282972a 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -133,9 +133,16 @@ xfs_sb_validate_fsb_count(
>  {
>  	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
>  	ASSERT(sbp->sb_blocklog >= BBSHIFT);
> +	uint64_t max_index;
> +	uint64_t max_bytes;
> +
> +	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
> +		return -EFBIG;
>  
>  	/* Limited by ULONG_MAX of page cache index */
> -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> +	max_index = max_bytes >> PAGE_SHIFT;
> +
> +	if (max_index > ULONG_MAX)
>  		return -EFBIG;
>  	return 0;
>  }
> -- 
> 2.34.1
> 
>