From 31e332b911fca54df467d264d7e2a2ef9317f3ca Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Mon, 6 Oct 2025 01:15:26 +0200 Subject: fs: add missing fences to I_NEW handling Suppose there are 2 CPUs racing inode hash lookup func (say ilookup5()) and unlock_new_inode(). In principle the latter can clear the I_NEW flag before prior stores into the inode were made visible. The former can in turn observe I_NEW is cleared and proceed to use the inode, while possibly reading from not-yet-published areas. Signed-off-by: Mateusz Guzik Signed-off-by: Christian Brauner --- include/linux/writeback.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 22dd4adc5667..e1e1231a6830 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -194,6 +194,10 @@ static inline void wait_on_inode(struct inode *inode) { wait_var_event(inode_state_wait_address(inode, __I_NEW), !(READ_ONCE(inode->i_state) & I_NEW)); + /* + * Pairs with routines clearing I_NEW. + */ + smp_rmb(); } #ifdef CONFIG_CGROUP_WRITEBACK -- cgit v1.2.3