From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sage Weil Subject: [PATCH 2/2] vfs: clean up real_lookup Date: Thu, 19 Mar 2009 13:16:30 -0700 Message-ID: <1237493790-5665-2-git-send-email-sage@newdream.net> References: <1237493790-5665-1-git-send-email-sage@newdream.net> Cc: Sage Weil To: linux-fsdevel@vger.kernel.org, hch@infradead.org, akpm@linux-foundation.org Return-path: Received: from cobra.newdream.net ([66.33.216.30]:44789 "EHLO cobra.newdream.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754573AbZCSURz (ORCPT ); Thu, 19 Mar 2009 16:17:55 -0400 In-Reply-To: <1237493790-5665-1-git-send-email-sage@newdream.net> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Get rid of the goto by flipping the if (!result) over. Make the comments a bit more descriptive. Fix a few kernel style problems. No functional changes. Signed-off-by: Sage Weil --- fs/namei.c | 65 +++++++++++++++++++++++++++++++---------------------------- 1 files changed, 34 insertions(+), 31 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index b9e7128..b98d916 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -461,19 +461,20 @@ ok: * This is called when everything else fails, and we actually have * to go to the low-level filesystem to find out what we should do.. * - * We get the directory semaphore, and after getting that we also + * We get the directory mutex, and after getting that we also * make sure that nobody added the entry to the dcache in the meantime.. * SMP-safe */ -static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) +static struct dentry *real_lookup(struct dentry *parent, struct qstr *name, + struct nameidata *nd) { - struct dentry * result; + struct dentry *result, *dentry; struct inode *dir = parent->d_inode; mutex_lock(&dir->i_mutex); /* * First re-do the cached lookup just in case it was created - * while we waited for the directory semaphore.. + * while we waited for the directory mutex. * * FIXME! This could use version numbering or similar to * avoid unnecessary cache lookups. @@ -486,38 +487,40 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup */ result = d_lookup(parent, name); - if (!result) { - struct dentry *dentry; - -do_the_lookup: - /* Don't create child dentry for a dead directory. */ - result = ERR_PTR(-ENOENT); - if (IS_DEADDIR(dir)) - goto out_unlock; - - dentry = d_alloc(parent, name); - result = ERR_PTR(-ENOMEM); - if (dentry) { - result = dir->i_op->lookup(dir, dentry, nd); + if (result) { + /* + * The cache was re-populated while we waited on the + * mutex. We need to revalidate, this time while + * holding i_mutex (to avoid another race). + */ + if (result->d_op && result->d_op->d_revalidate) { + result = do_revalidate(result, nd); if (result) - dput(dentry); - else - result = dentry; + goto out_unlock; + /* + * The dentry was left behind invalid. Just + * do the lookup. + */ + } else { + goto out_unlock; } -out_unlock: - mutex_unlock(&dir->i_mutex); - return result; } - /* - * Uhhuh! Nasty case: the cache was re-populated while - * we waited on the semaphore. Need to revalidate. - */ - if (result->d_op && result->d_op->d_revalidate) { - result = do_revalidate(result, nd); - if (!result) - goto do_the_lookup; + /* Don't create child dentry for a dead directory. */ + result = ERR_PTR(-ENOENT); + if (IS_DEADDIR(dir)) + goto out_unlock; + + dentry = d_alloc(parent, name); + result = ERR_PTR(-ENOMEM); + if (dentry) { + result = dir->i_op->lookup(dir, dentry, nd); + if (result) + dput(dentry); + else + result = dentry; } +out_unlock: mutex_unlock(&dir->i_mutex); return result; } -- 1.5.6.5