From b06c684d3984ef64e792ec3e89889c96cab97b5e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 31 Oct 2023 00:23:35 -0400 Subject: dentry_kill(): don't bother with retain_dentry() on slow path We have already checked it and dentry used to look not worthy of keeping. The only hard obstacle to evicting dentry is non-zero refcount; everything else is advisory - e.g. memory pressure could evict any dentry found with refcount zero. On the slow path in dentry_kill() we had dropped and regained ->d_lock; we must recheck the refcount, but everything else is not worth bothering with. Note that filesystem can not count upon ->d_delete() being called for dentry - not even once. Again, memory pressure (as well as d_prune_aliases(), or attempted rmdir() of ancestor, or...) will not call ->d_delete() at all. So from the correctness point of view we are fine doing the check only once. And it makes things simpler down the road. Signed-off-by: Al Viro --- fs/dcache.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index b527db8e5901..80992e49561c 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -739,14 +739,10 @@ slow_positive: spin_lock(&dentry->d_lock); parent = lock_parent(dentry); got_locks: - if (unlikely(dentry->d_lockref.count != 1)) { - dentry->d_lockref.count--; - } else if (likely(!retain_dentry(dentry))) { - dentry->d_lockref.count--; + dentry->d_lockref.count--; + if (likely(dentry->d_lockref.count == 0)) { __dentry_kill(dentry); return parent; - } else { - dentry->d_lockref.count--; } /* we are keeping it, after all */ if (inode) -- cgit v1.2.3