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AJvYcCVxoFrpccxoATkh7YwZjzhNIUR/T0dGLIO67DlR5DFKljkzJFVUVX7eG1RzOxC6j0o0aq1KnABCtg==@kvack.org X-Gm-Message-State: AOJu0Yy8dZY43Q2XgzM62o+gHSqZwvOhG2zXBImyiWRWoPUsQS4EbvmJ ymX+Qh/M6wxqirKGx62mXSHXszUm/b5AQ2WVGMBDjb6fw4/eY5xm2YDGsqKMOO8GP6hSnfXyIFL tDgWvatTAuQ0hwx/ORwo7ONzyd5Fm+5s27r2fHhP8Kg== X-Gm-Gg: ASbGncvs2ezqnfM7rqg5aCOnNwd4XxaUD+uNCJZBWpq042wBhlTLGjtUs4//fvxR8D8 Ry5wsLWEqqkrvJcZ7pwBjlEsaYGGNpNeVQEhr7FFJ2gbtY85QZBxWdNnLv6i52gezKSI0vyW2h3 V3gdATD5VIJn1m0r8J0nXNZZ1e1cOJME4Os0asikTATrS9+bKI1QuYpuXcN+O2jg9zI1gphzm1e KZXbgYQFNHR30KZGqWonN0rpMyzuoOgSr0N X-Google-Smtp-Source: AGHT+IGfptemIFohfTy+lGP+G94GDKuCT6cuywROwctnniSHmTHsaA0aWmc8jBz7sUxZychQu36GLP7/p/srVhhMhOs= X-Received: by 2002:a17:907:dac:b0:afe:e1e3:36a2 with SMTP id a640c23a62f3a-b1bb6beec18mr411560666b.31.1758141419817; Wed, 17 Sep 2025 13:36:59 -0700 (PDT) MIME-Version: 1.0 References: <4z3imll6zbzwqcyfl225xn3rc4mev6ppjnx5itmvznj2yormug@utk6twdablj3> <20250917201408.GX39973@ZenIV> <20250917203435.GA39973@ZenIV> In-Reply-To: <20250917203435.GA39973@ZenIV> From: Max Kellermann Date: Wed, 17 Sep 2025 22:36:48 +0200 X-Gm-Features: AS18NWCHuKu5FkRi5MWoSntMnfUkf_rpkIBRpCjAVUQOvwmxI5LYn5BBnB2B2gI Message-ID: Subject: Re: Need advice with iput() deadlock during writeback To: Al Viro Cc: Mateusz Guzik , linux-fsdevel , Linux Memory Management List , ceph-devel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 47B352000F X-Stat-Signature: fo1cftdpgptnpwtpxco353yebtjuma53 X-Rspam-User: X-HE-Tag: 1758141421-744709 X-HE-Meta: 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 k2PRH08/ b73bR68WP2HQhSMLLjdTY749RtERJVi9qfKtITNOyp01g0ApD9YpAGggzLrRbf1hfJKqpjav+9vn93AtgR7axT1rufdZPvtjzzV1SOZCOvYZaQZxgYEXKC6jxK1dtw0ec1dTjf7svf0ahLuIzDmUIXiKQYlFcI6PG7+d1NjncO27hVb/bTt4Ie8rEHGOyHcZdK+LuBD4WdsF1NipNLGBA9lnZXco01H8fbdsdEBr6spUoSKcLMs0OW7bkeA== 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 Wed, Sep 17, 2025 at 10:34=E2=80=AFPM Al Viro = wrote: > Suppose two threads do umount() on two different filesystems. The first > one to flush picks *everything* you've delayed and starts handling that. > The second sees nothing to do and proceeds to taking the filesystem > it's unmounting apart, right under the nose of the first thread doing > work on both filesystems... Each filesystem (struct ceph_fs_client) has its own inode_wq.