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Date: Tue, 11 Jun 2024 07:59:06 +0200
From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
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Subject: Re: [PATCH 05/26] loop: regularize upgrading the lock size for
 direct I/O
Message-ID: <20240611055906.GA3640@lst.de>
References: <20240611051929.513387-1-hch@lst.de> <20240611051929.513387-6-hch@lst.de> <dabc33cd-feb9-4263-8f6e-4d2ab3d71430@kernel.org>
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On Tue, Jun 11, 2024 at 02:56:59PM +0900, Damien Le Moal wrote:
> > +	if (!bsize)
> > +		bsize = loop_default_blocksize(lo, inode->i_sb->s_bdev);
> 
> If bsize is specified and there is a backing dev used with direct IO, should it
> be checked that bsize is a multiple of bdev_logical_block_size(backing_bdev) ?

For direct I/O that check would be useful.  For buffered I/O we can do
read-modify-write cycles.  However this series is already huge and not
primarily about improving the loop driver parameter validation, so
I'll defer this for now.