linux-kernel - [PATCH v2 23/29] staging/lustre/llite: ll_revalidate

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Date:	Mon, 20 Jun 2016 16:55:46 -0400
From:	Oleg Drokin <green@...uxhacker.ru>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	devel@...verdev.osuosl.org,
	Andreas Dilger <andreas.dilger@...el.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Lustre Development List <lustre-devel@...ts.lustre.org>,
	Oleg Drokin <oleg.drokin@...el.com>,
	Oleg Drokin <green@...uxhacker.ru>
Subject: [PATCH v2 23/29] staging/lustre/llite: ll_revalidate_dentry update

From: Oleg Drokin <oleg.drokin@...el.com>

There are a couple of cases in ll_revalidate_dentry() where
we are pretty sure the dentry is valid, so check for them early
and save more expensive checks for later.

Signed-off-by: Oleg Drokin <green@...uxhacker.ru>
---
 drivers/staging/lustre/lustre/llite/dcache.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/staging/lustre/lustre/llite/dcache.c b/drivers/staging/lustre/lustre/llite/dcache.c
index d964f4f..581a63a 100644
--- a/drivers/staging/lustre/lustre/llite/dcache.c
+++ b/drivers/staging/lustre/lustre/llite/dcache.c
@@ -302,6 +302,17 @@ static int ll_revalidate_dentry(struct dentry *dentry,
 {
 	struct inode *dir = d_inode(dentry->d_parent);
 
+	/* If this is intermediate component path lookup and we were able to get
+	 * to this dentry, then its lock has not been revoked and the
+	 * path component is valid.
+	 */
+	if (lookup_flags & LOOKUP_PARENT)
+		return 1;
+
+	/* Symlink - always valid as long as the dentry was found */
+	if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))
+		return 1;
+
 	/*
 	 * if open&create is set, talk to MDS to make sure file is created if
 	 * necessary, because we can't do this in ->open() later since that's
-- 
2.7.4