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Sat, 12 Apr 2025 16:39:26 +0000 (UTC) Received: from pasta.fast.eng.rdu2.dc.redhat.com (unknown [10.45.224.37]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 69ACE180174E; Sat, 12 Apr 2025 16:39:23 +0000 (UTC) From: Andreas Gruenbacher To: cgroups@vger.kernel.org Cc: Jan Kara , Tetsuo Handa , Rafael Aquini , gfs2@lists.linux.dev, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Gruenbacher Subject: [PATCH v3 2/2] writeback: Fix false warning in inode_to_wb() Date: Sat, 12 Apr 2025 18:39:12 +0200 Message-ID: <20250412163914.3773459-3-agruenba@redhat.com> In-Reply-To: <20250412163914.3773459-1-agruenba@redhat.com> References: <20250412163914.3773459-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Rspamd-Queue-Id: ECBAB18000D X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: q9twcmzgz66kxaf7dyb8wstfxjtbo5si X-HE-Tag: 1744475971-940281 X-HE-Meta: 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 9EjrFnz9 CLuShh+uNCPvpirV65m4/I8cbApJHwNLPcQreU45kmAmagEh67LQo/G+r1Du5i5Bds9MdWCvMEjevfKJOI/tBs188HUQWn0I0eVygpqLMfmdPTgzAo7jAczpT2GIuY43I24uUj5uqo3zHXp82RIomjBKtxh0jnFi43Z3l9y4GBpXn9NN1N1EaoxDSO/xWewffVmFnfN3fj0uozcB3rmGPtY9MmqmO/Ui3D9NHtvm8Aa8AWeuikxMLYlb9iAvNxBRTALlh6s6kXWfsUB7ZkIRgyNhtv7qDFalHtZeN+XT6zjMmOqmZbPod3xZCC5obxJpRV8AnWEowH1L8yXG9GC0Hrfx3WM8eb1G4eGP7TqxS3Nc5mcIVxQwEFv8vecGkchOYL9lq 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: From: Jan Kara inode_to_wb() is used also for filesystems that don't support cgroup writeback. For these filesystems inode->i_wb is stable during the lifetime of the inode (it points to bdi->wb) and there's no need to hold locks protecting the inode->i_wb dereference. Improve the warning in inode_to_wb() to not trigger for these filesystems. Signed-off-by: Jan Kara Reviewed-by: Andreas Gruenbacher signed-off-by:Andreas somewhere. I made that change to the mm.git copy --- include/linux/backing-dev.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 8e7af9a03b41..e721148c95d0 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -249,6 +249,7 @@ static inline struct bdi_writeback *inode_to_wb(const struct inode *inode) { #ifdef CONFIG_LOCKDEP WARN_ON_ONCE(debug_locks && + (inode->i_sb->s_iflags & SB_I_CGROUPWB) && (!lockdep_is_held(&inode->i_lock) && !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) && !lockdep_is_held(&inode->i_wb->list_lock)));