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b=dmHA4CXBlOondQYr1s3wHnFJbTwzL5Y5dFCsnYGAfYRQw4/QdERsmrgWiyu+afWe2 WU9V/RU64WTZ1H+iTCHhm9s58493GI5tvupt1fatfNVKkFZuGUNW9v6jY243bR9df/ li9Li2Jz4DCEqxcQtEFgiMNoLMQ4WGA+f8fjPkdF+L5dGGap/gK2ql11RgeFpJL0Ry 4D8lniQBP1lHhac0lZF/P5ewQjsiLvOJ9I4kDVZh5lSlfN0zftGqymhQxrQWgtpwqU JMJ5ALQbwkt6kM4tiMr6E4r0a4I3jZyrWv2hAR/GR9UuQRRtLbtxidcFQR9BEFgu2p Oxjp7WTldZhcg== Message-ID: <6d0948f5-e739-49f3-8e23-359ddbf3da8f@kernel.org> Date: Wed, 26 Nov 2025 11:41:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 2/2] fs/writeback: skip inodes with potential writeback hang in wait_sb_inodes() To: Miklos Szeredi , Joanne Koong Cc: akpm@linux-foundation.org, linux-mm@kvack.org, shakeel.butt@linux.dev, athul.krishna.kr@protonmail.com, stable@vger.kernel.org References: <20251120184211.2379439-1-joannelkoong@gmail.com> <20251120184211.2379439-3-joannelkoong@gmail.com> <5c1630ac-d304-4854-9ba6-5c9cc1f78be5@kernel.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: EB84480005 X-Stat-Signature: 84uad7bbeafc4ppcwc7enikqu3gmjyr8 X-HE-Tag: 1764153722-101133 X-HE-Meta: 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 NEzpJi/W gUaMJTrYHOLtBPVUzRMwvv+NRb6STL69TZCzl8TZNg9vuPUgbaXxZWfro2wruXq5CGwQC4b80DBY4AGxCEbz+fMifYFPl9+tCWdggWeYqZYck89dx4x7ETzZjQl29yho766MZ3IkZbc/7VxZVbCNyao1+oRnqCBord3/FWH2gIdcREFjgWfr3t4vRtb3KqORjGrktF/zwAoPh4W4vAbAGfrioDmZG06VE4hqhK3u1Q71pjW4RnLHj26VGMxIxmM9698R83gs/+B9t6nVVXYPmY8gvsU5bmDV+Bu7o 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 11/26/25 11:19, Miklos Szeredi wrote: > On Tue, 25 Nov 2025 at 02:10, Joanne Koong wrote: > >> Prior to the changes added in commit 0c58a97f919c ("fuse: remove tmp >> folio for writebacks and internal rb tree"), fuse didn't ensure that >> data was written back for sync. The folio was marked as not under >> writeback anymore, even if it was still under writeback. > > This is the main point. Fuse has existed for 20 years without data > integrity guarantees. Reverting to that behavior is *not* a > regression, it's simply a decades old bug. And solving that bug is > darn hard, which is why it's not an option at this point. Yes, and it should be clearly spelled out in the patch descriptions that this is a fuse-only thing, and why it is a fuse-only thing. It's not a "we don't have data integrity because writeback may hang", it's a "we don't have data integrity because fuse never supported it, so waiting here is simply not required". -- Cheers David