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b=CBuBU4gQ4AkZBrbUoPRDpNX7SRB7Jc7wspQPnrfo/ldXBoOBchIV8+zxKvHz6Ut6P ec1XLPh2xj3CcWAkOZRDjJh0FDRR1pxWLJR7GUu2bA/k4V4kLq6phPh3HeBnn+9sIY AuOljrHMMdIRPejyf0VkLJs8P40rfOcNbC5SEDIA= Date: Sat, 3 Jan 2026 10:03:10 -0800 From: Andrew Morton To: Joanne Koong Cc: david@redhat.com, miklos@szeredi.hu, linux-mm@kvack.org, athul.krishna.kr@protonmail.com, j.neuschaefer@gmx.net, carnil@debian.org, linux-fsdevel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 1/1] fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes() Message-Id: <20260103100310.7181968cda53b14def0455b3@linux-foundation.org> In-Reply-To: <20251215030043.1431306-2-joannelkoong@gmail.com> References: <20251215030043.1431306-1-joannelkoong@gmail.com> <20251215030043.1431306-2-joannelkoong@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 24D831A001C X-Stat-Signature: uzoo7t8be6b9gpazrs4ecnf63bysucoa X-HE-Tag: 1767463391-385317 X-HE-Meta: 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 sAECT7b/ uK2Mr+DROm5qLVggYPJR7JhFvGUbDk2LML/jkXD+uSTXNNVQjaGfBnUvySmw4mirW3tw4jiwwf0nMs43lzNd8hyFVhILbdu0TUCq+VFWUn5VDWIBpBDJJrFxBfjxUAr7LSL7VLS0zFfpU/C5kjnCIU+0MaJ9FFZCTqAl5Lz3A89no3WPwbohSrIxqK/0KcXV8MIFGRXePErvsJhVQEIiD7ASGRkB2r9ZM028Q0Lz6eF7HjOkurrpXhpZ/5/lHxLa+bYSemk3enUeIsh7BBCRaAX5zoTwyO2Ikal0xE1OwwqsSyRMDWNc31C5KeEW88PNfW51i8RK+L0XhdkLM/x1KUnVxXTD+OqCOpQa66LPXg7n0jrBbIEWBfSrq9TGog+JuODACUvnbde1jM3oij8dpPfOCAPiZT6G9pADGN2NKLlaWc4Q= 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 Sun, 14 Dec 2025 19:00:43 -0800 Joanne Koong wr= ote: > Skip waiting on writeback for inodes that belong to mappings that do not > have data integrity guarantees (denoted by the AS_NO_DATA_INTEGRITY > mapping flag). >=20 > This restores fuse back to prior behavior where syncs are no-ops. This > is needed because otherwise, if a system is running a faulty fuse > server that does not reply to issued write requests, this will cause > wait_sb_inodes() to wait forever. >=20 > Fixes: 0c58a97f919c ("fuse: remove tmp folio for writebacks and internal = rb tree") > Reported-by: Athul Krishna > Reported-by: J. Neusch=E4fer > Cc: stable@vger.kernel.org > Signed-off-by: Joanne Koong > > .. > > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -2751,7 +2751,8 @@ static void wait_sb_inodes(struct super_block *sb) > * do not have the mapping lock. Skip it here, wb completion > * will remove it. > */ > - if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) > + if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK) || > + mapping_no_data_integrity(mapping)) > continue; It's not obvious why a no-data-integrity mapping would want to skip writeback - what do these things have to do with each other? So can we please have a v2 which has a comment here explaining this to the reader?