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Date: Fri, 25 Sep 2026 08:12:20 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Carlos Maiolino <cem@kernel.org>,
	Jens Axboe <axboe@kernel.dk>,
	Christian Brauner <brauner@kernel.org>, linux-xfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 10/21] xfs: calculate the log reservation for logging
 data checksum buffers
Message-ID: <20260925061220.GA3637@lst.de>
References: <20260924100032.2733101-1-hch@lst.de> <20260924100032.2733101-11-hch@lst.de> <20260924223021.GK2705364@frogsfrogsfrogs>
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On Thu, Sep 24, 2026 at 03:30:21PM -0700, Darrick J. Wong wrote:
> > +	resp->tr_csum.tr_logres =
> > +		xfs_calc_csum_reservation(mp, XFS_RTCSUM_MAX_WRITE);
> > +	resp->tr_csum.tr_logcount = XFS_DEFAULT_LOG_COUNT;
> 
> Going back to a question I had in "xfs: prepare
> xfs_rtfile_initialize_blocks for larger than FSB blocks", should we be
> using tr_csum for the transaction to write out new checksum file block
> contents?

They actually are different reservations.  Preparing the file writes
one csumblock at a time, while the write path can write upto three
right now as it only has an absolute size limit, but no alignment
limit.