From: Mateusz Guzik Date: Thu, 9 Oct 2025 07:59:16 +0000 (+0200) Subject: fs: spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cb5db358ab5769cbd3e8e864f14af321126cccdb;p=thirdparty%2Flinux.git fs: spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb The incomming helpers don't ship with _release/_acquire variants, for the time being anyway. Signed-off-by: Mateusz Guzik Signed-off-by: Christian Brauner --- diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 2b35e80037fee..9cda19a40ca2e 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 3e64f14739dd2..065cba5dc111b 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);