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Thu, 20 Nov 2025 10:42:45 -0800 (PST) From: Joanne Koong To: akpm@linux-foundation.org Cc: david@redhat.com, linux-mm@kvack.org, shakeel.butt@linux.dev, athul.krishna.kr@protonmail.com, miklos@szeredi.hu, stable@vger.kernel.org Subject: [PATCH v1 2/2] fs/writeback: skip inodes with potential writeback hang in wait_sb_inodes() Date: Thu, 20 Nov 2025 10:42:11 -0800 Message-ID: <20251120184211.2379439-3-joannelkoong@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251120184211.2379439-1-joannelkoong@gmail.com> References: <20251120184211.2379439-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit During superblock writeback waiting, skip inodes where writeback may take an indefinite amount of time or hang, as denoted by the AS_WRITEBACK_MAY_HANG mapping flag. Currently, fuse is the only filesystem with this flag set. For a properly functioning fuse server, writeback requests are completed and there is no issue. However, if there is a bug in the fuse server and it hangs on writeback, then without this change, wait_sb_inodes() will wait forever. Signed-off-by: Joanne Koong Fixes: 0c58a97f919c ("fuse: remove tmp folio for writebacks and internal rb tree") Reported-by: Athul Krishna --- fs/fs-writeback.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 2b35e80037fe..eb246e9fbf3d 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -2733,6 +2733,9 @@ static void wait_sb_inodes(struct super_block *sb) if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) continue; + if (mapping_writeback_may_hang(mapping)) + continue; + spin_unlock_irq(&sb->s_inode_wblist_lock); spin_lock(&inode->i_lock); -- 2.47.3