From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 10 May 2012 18:06:18 +0000 (-0700)
Subject: vfs: remove unnecessary d_unhashed() check from __d_lookup_rcu
X-Git-Tag: v3.5-rc1~192^2~3
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8c01a529b861ba97c7d78368e6a5d4d42e946f75;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git

vfs: remove unnecessary d_unhashed() check from __d_lookup_rcu

The check for d_unhashed() is not strictly incorrect, but at the same
time it is also not sensible.  The actual dentry removal from the dentry
hash chains is totally asynchronous to the __d_lookup_rcu() logic, and
we depend on __d_drop() updating the sequence number to invalidate any
lookup of an unhashed dentry.

So checking d_unhashed() is not incorrect, but it's not useful either:
the code has to work correctly even without it. So just remove it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/dcache.c b/fs/dcache.c
index 539943e..c4d2ff8 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1871,8 +1871,6 @@ seqretry:
 		seq = raw_seqcount_begin(&dentry->d_seq);
 		if (dentry->d_parent != parent)
 			continue;
-		if (d_unhashed(dentry))
-			continue;
 		*seqp = seq;
 
 		if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {