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[46.135.66.155]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b5007639379sm553509366b.48.2025.10.09.00.59.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Oct 2025 00:59:42 -0700 (PDT) From: Mateusz Guzik To: brauner@kernel.org Cc: viro@zeniv.linux.org.uk, jack@suse.cz, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, josef@toxicpanda.com, kernel-team@fb.com, amir73il@gmail.com, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-unionfs@vger.kernel.org, Mateusz Guzik Subject: [PATCH v7 02/14] fs: spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb Date: Thu, 9 Oct 2025 09:59:16 +0200 Message-ID: <20251009075929.1203950-3-mjguzik@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251009075929.1203950-1-mjguzik@gmail.com> References: <20251009075929.1203950-1-mjguzik@gmail.com> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The incomming helpers don't ship with _release/_acquire variants, for the time being anyway. Signed-off-by: Mateusz Guzik --- fs/fs-writeback.c | 5 +++-- include/linux/backing-dev.h | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 2b35e80037fe..9cda19a40ca2 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -476,10 +476,11 @@ static bool inode_do_switch_wbs(struct inode *inode, switched = true; skip_switch: /* - * Paired with load_acquire in unlocked_inode_to_wb_begin() and + * Paired with an acquire fence in unlocked_inode_to_wb_begin() and * ensures that the new wb is visible if they see !I_WB_SWITCH. */ - smp_store_release(&inode->i_state, inode->i_state & ~I_WB_SWITCH); + smp_wmb(); + inode->i_state &= ~I_WB_SWITCH; xa_unlock_irq(&mapping->i_pages); spin_unlock(&inode->i_lock); diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 3e64f14739dd..065cba5dc111 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -277,10 +277,11 @@ unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie) rcu_read_lock(); /* - * Paired with store_release in inode_switch_wbs_work_fn() and + * Paired with a release fence in inode_do_switch_wbs() and * ensures that we see the new wb if we see cleared I_WB_SWITCH. */ - cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH; + cookie->locked = inode->i_state & I_WB_SWITCH; + smp_rmb(); if (unlikely(cookie->locked)) xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags); -- 2.34.1