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Received: from willy by casper.infradead.org with local (Exim 4.98.1 #2 (Red Hat Linux)) id 1tznN6-00000008YS0-2Dgm; Wed, 02 Apr 2025 01:58:28 +0000 Date: Wed, 2 Apr 2025 02:58:28 +0100 From: Matthew Wilcox To: Jan Kara , Luis Chamberlain , brauner@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, riel@surriel.com, hannes@cmpxchg.org, oliver.sang@intel.com, david@redhat.com, axboe@kernel.dk, hare@suse.de, david@fromorbit.com, djwong@kernel.org, ritesh.list@gmail.com, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, gost.dev@samsung.com, p.raghav@samsung.com, da.gomez@samsung.com Subject: Re: [PATCH 2/3] fs/buffer: avoid races with folio migrations on __find_get_block_slow() Message-ID: References: <20250330064732.3781046-1-mcgrof@kernel.org> <20250330064732.3781046-3-mcgrof@kernel.org> <20250401214951.kikcrmu5k3q6qmcr@offworld> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250401214951.kikcrmu5k3q6qmcr@offworld> X-Rspamd-Queue-Id: C7DAB180004 X-Stat-Signature: j6rtpfin6acfzhc69utknxwiuuka7m76 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1743559124-997114 X-HE-Meta: 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 VGD5yq2o 9jYLQZrsljX6T/XRIb+YwRtveaq9EEJ23cJ7jLJiD8HwIpy+BFp4zPYV6E3S1OtUzAMK3ORqkaNFKDpSF2Ky24xHxBXYck5QkbSEn+OKJ3LA4FbPGgkfctEzP6i0AubuTN3Fb3M7u38c73PLNhzOOZ2BTh99bnfYrIuu2em6RPcghgKjF/QA2sr8hCREL5+/Ux7cZJZHh3KpnR2bRMlTeXxEGHCimhiDNKSKC/t8piuzZ+1WQkqk+84aMs85pQhncUulNxE6rZaSHxOQU1MgwPfRJs7dXPkuWCogbxgCKtwyxQPRvJTz6Ft6ILXKGMqW/LwAC4HXITZqK96JDEdCJdROIuULEZWwjdjbWWJHwZbvBEAiVHDZtev+iTA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Apr 01, 2025 at 02:49:51PM -0700, Davidlohr Bueso wrote: > So the below could be tucked in for norefs only (because this is about the addr > space i_private_lock), but this also shortens the hold time; if that matters > at all, of course, vs changing the migration semantics. I like this approach a lot better. One wrinkle is that it doesn't seem that we need to set the BH_Migrate bit on every buffer; we could define that it's only set on the head BH, right?