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AJvYcCV/JyCsqBtUCg89792bag9k0sv7JaEh8+wWjL+SVE4suHzptgm+bI+Q/ntrnjBWo/zSJufRjVN2bQ==@kvack.org X-Gm-Message-State: AOJu0YwBnq5Ys+EuBfk/ViTIjIsCZxVN+cTJNVV253yLhxfyIh6rSXyN Y1BdGGmFgoX2KMUiYKskP7oPZllB8osuVOnx5Oy//iDMleVpGFV97rdX7BHOADkd+LR1DAiGYnC GQK5XX+zmw1tUIJnIUvdNscHPir9wq+8= X-Gm-Gg: ASbGnctqAwiBjhjd5LW6/wggtSbMVcuBDZQMc4fn3dJBoT7wppsaku6pRcnkTOpVCHn NqhD09pyHQJwweKUIcuSQtw//kWhet2DcW5gNc+X0RYD/eUSjAXk6rcrHFrRSlHTxWp+Kj/I46p HT1N2M6fyWe2/hEc5Trf4IkLgVRgHKMw9pJXk2r/00N3wQRCoWeFeN9lcXGWFuk44zhep4Glmz1 +Z1IuNqkwekMlScXB68mDzOGlX+Xv4q9N4zAE4Be07dUduJyRYIAGNWveF6AO55b2Ulzw== X-Google-Smtp-Source: AGHT+IEa5T+vJspuWQ+toPhdixw0WwlXC4G0HJVZEYNsBGrI4UEp3MsHvbWsFOZ191NkPJIFH9UZtf+mHSYJj1eRNx0= X-Received: by 2002:a05:622a:4ca:b0:4ee:15af:b938 with SMTP id d75a77b69052e-4ee5892e29dmr992241cf.70.1763674115151; Thu, 20 Nov 2025 13:28:35 -0800 (PST) MIME-Version: 1.0 References: <20251120184211.2379439-1-joannelkoong@gmail.com> <20251120184211.2379439-2-joannelkoong@gmail.com> <7fae20ca-d7b0-4786-8c31-288648db8ad0@kernel.org> In-Reply-To: <7fae20ca-d7b0-4786-8c31-288648db8ad0@kernel.org> From: Joanne Koong Date: Thu, 20 Nov 2025 13:28:24 -0800 X-Gm-Features: AWmQ_bmnvTHHOQkyw-5ik9LsEU1gIAn8vSNbEvhvGRrj7a058LOg6piKf3ugJVk Message-ID: Subject: Re: [PATCH v1 1/2] mm: rename AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM to AS_WRITEBACK_MAY_HANG To: "David Hildenbrand (Red Hat)" Cc: akpm@linux-foundation.org, linux-mm@kvack.org, shakeel.butt@linux.dev, athul.krishna.kr@protonmail.com, miklos@szeredi.hu, stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: bexqc64eyzy6466ym79xcpotrih4ckj1 X-Rspam-User: X-Rspamd-Queue-Id: 2EA00C000A X-Rspamd-Server: rspam01 X-HE-Tag: 1763674116-651163 X-HE-Meta: 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 /QkozL+s WNXzVfNStFlPK4DgWgiZhHUzrot4TCc0yOuE/ai3Xz8fu23+zG23g4cA+hjtmq9rXrp64RDpGAumcm9foBKqeEw2uTBFTyqcJ6TNMA7+VDVlxTssGjjyzAr338vKz4LdIAn81JICFJiWvNS42HghmL7R/UZ0KGAgjVrL/v3f9iHRfW88d6369nO/zmN3ywYnfP7DkkC92jsJEeNtVvPWOcbEzDqJWnhwfnmQJwpLCbnasczWtxz6My18lOx+q8lDxHVKB/wJ9XVVGR1jEUxaivETOmEH1h6/OvH/3fUHqEvvgTG7pvSMwyCw1kFWnQNN38lMGiWRZYXkJOWvdFlPPCtH9GZTW1eNTmcbYI9Jd8pkrOql1yPKBwJ2MF6jWaW5x5BAiYrJD+K1rNMVNFzq6/4VjKYag1LXJDZlovVkUb56x/SY= 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 Thu, Nov 20, 2025 at 12:08=E2=80=AFPM David Hildenbrand (Red Hat) wrote: > > On 11/20/25 19:42, Joanne Koong wrote: > > AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM was added to avoid waiting on > > writeback during reclaim for inodes belonging to filesystems where > > a) waiting on writeback in reclaim may lead to a deadlock or > > b) a writeback request may never complete due to the nature of the > > filesystem (unrelated to reclaim) > > > > Rename AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM to the more generic > > AS_WRITEBACK_MAY_HANG to reflect mappings where writeback may hang wher= e > > the cause could be unrelated to reclaim. > > > > This allows us to later use AS_WRITEBACK_MAY_HANG to mitigate other > > scenarios such as possible hangs when sync waits on writeback. > > Hmm, there is a difference whether writeback may hang or whether > writeback may deadlock. > > In particular, isn't it the case that writeback on any filesystem might > effectively hang forever on I/O errors etc? > > Is this going back to the previous flag semantics before we decided on > AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM? (I'd have to look at the previous > discussions, but "writeback may take an indefinite amount" in patch #2 > pretty much looks like what I remember there) Yes, I think if we keep AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM, then we would need another flag to denote the inode should be skipped in wait_sb_inodes(), which seems unideal. I was considering renaming this to AS_WRITEBACK_INDETERMINATE but I remember everyone hated that name. Thanks, Joanne > > -- > Cheers > > David