It's possible for the atime to be updated with a fine-grained timestamp and then later get an update that uses a coarse-grained timestamp which makes the atime appear to go backward. Fix this by only updating the atime if "now" is later than the current value. Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Closes: https://lore.kernel.org/oe-lkp/202309071017.a64aca5e-oliver.sang@xxxxxxxxx Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- fs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 54237f4242ff..cf4726b7f4b5 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1905,7 +1905,7 @@ int inode_update_timestamps(struct inode *inode, int flags) } if (flags & S_ATIME) { - if (!timespec64_equal(&now, &inode->i_atime)) { + if (timespec64_compare(&inode->i_atime, &now) < 0) { inode->i_atime = now; updated |= S_ATIME; } @@ -1991,7 +1991,7 @@ bool atime_needs_update(const struct path *path, struct inode *inode) if (!relatime_need_update(mnt, inode, now)) return false; - if (timespec64_equal(&inode->i_atime, &now)) + if (timespec64_compare(&inode->i_atime, &now) >= 0) return false; return true; -- 2.41.0
