Return-Path: linux-nfs-owner@vger.kernel.org Received: from cantor2.suse.de ([195.135.220.15]:52090 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755165AbaCEDBP (ORCPT ); Tue, 4 Mar 2014 22:01:15 -0500 From: NeilBrown To: Trond Myklebust Date: Wed, 05 Mar 2014 14:00:28 +1100 Subject: [PATCH 1/8] NFS: nfs4_lookup_revalidate: only evaluate parent if it will be used. Cc: linux-nfs@vger.kernel.org Message-ID: <20140305030028.27421.54675.stgit@notabene.brown> In-Reply-To: <20140305025813.27421.23871.stgit@notabene.brown> References: <20140305025813.27421.23871.stgit@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: nfs4_lookup_revalidate only uses 'parent' to get 'dir', and only uses 'dir' if 'inode == NULL'. So we don't need to find out what 'parent' or 'dir' is until we know that 'inode' is NULL. By moving 'dget_parent' inside the 'if', we can reduce the number of call sites for 'dput(parent)'. Signed-off-by: NeilBrown --- fs/nfs/dir.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index be38b573495a..f5509f95f261 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1496,9 +1496,7 @@ EXPORT_SYMBOL_GPL(nfs_atomic_open); static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) { - struct dentry *parent = NULL; struct inode *inode; - struct inode *dir; int ret = 0; if (flags & LOOKUP_RCU) @@ -1512,34 +1510,35 @@ static int nfs4_lookup_revalidate(struct dentry *dentry, unsigned int flags) goto no_open; inode = dentry->d_inode; - parent = dget_parent(dentry); - dir = parent->d_inode; /* We can't create new files in nfs_open_revalidate(), so we * optimize away revalidation of negative dentries. */ if (inode == NULL) { + struct dentry *parent; + struct inode *dir; + + parent = dget_parent(dentry); + dir = parent->d_inode; if (!nfs_neg_need_reval(dir, dentry, flags)) ret = 1; + dput(parent); goto out; } /* NFS only supports OPEN on regular files */ if (!S_ISREG(inode->i_mode)) - goto no_open_dput; + goto no_open; /* We cannot do exclusive creation on a positive dentry */ if (flags & LOOKUP_EXCL) - goto no_open_dput; + goto no_open; /* Let f_op->open() actually open (and revalidate) the file */ ret = 1; out: - dput(parent); return ret; -no_open_dput: - dput(parent); no_open: return nfs_lookup_revalidate(dentry, flags); }