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From: NeilBrown <neilb@suse.com>
To: Oleg Drokin <oleg.drokin@intel.com>,
	Greg Kroah-Hartman <greg@kroah.com>,
	Andreas Dilger <andreas.dilger@intel.com>
Cc: Lustre Development List <lustre-devel@lists.lustre.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH 4/6] staging: lluste: llite: simplify ll_find_alias()
Date: Wed, 02 Aug 2017 13:06:18 +1000	[thread overview]
Message-ID: <150164317827.13199.14294676526176745668.stgit@noble> (raw)
In-Reply-To: <150164273003.13199.7841976922211510658.stgit@noble>

Now that ll_find_alias is only searching for one type
of dentry, we can return as soon as we find it.
This allows substantial simplification, and brings the
bonus that we don't need to take the d_lock again just
to increment the ref-count.  We can increment it immediately
that the dentry is found.

Signed-off-by: NeilBrown <neilb@suse.com>
---
 drivers/staging/lustre/lustre/llite/namei.c |   23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/namei.c b/drivers/staging/lustre/lustre/llite/namei.c
index 329038a10a07..51838eed501a 100644
--- a/drivers/staging/lustre/lustre/llite/namei.c
+++ b/drivers/staging/lustre/lustre/llite/namei.c
@@ -382,13 +382,11 @@ void ll_i2gids(__u32 *suppgids, struct inode *i1, struct inode *i2)
  */
 static struct dentry *ll_find_alias(struct inode *inode, struct dentry *dentry)
 {
-	struct dentry *alias, *invalid_alias;
+	struct dentry *alias;
 
 	if (hlist_empty(&inode->i_dentry))
 		return NULL;
 
-	invalid_alias = NULL;
-
 	spin_lock(&inode->i_lock);
 	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
 		LASSERT(alias != dentry);
@@ -398,22 +396,17 @@ static struct dentry *ll_find_alias(struct inode *inode, struct dentry *dentry)
 		    alias->d_name.hash == dentry->d_name.hash       &&
 		    alias->d_name.len == dentry->d_name.len	 &&
 		    memcmp(alias->d_name.name, dentry->d_name.name,
-			   dentry->d_name.len) == 0)
-			invalid_alias = alias;
-		spin_unlock(&alias->d_lock);
-
-		if (invalid_alias)
-			break;
-	}
-	alias = invalid_alias ?: NULL;
-	if (alias) {
-		spin_lock(&alias->d_lock);
-		dget_dlock(alias);
+			   dentry->d_name.len) == 0) {
+			dget_dlock(alias);
+			spin_unlock(&alias->d_lock);
+			spin_unlock(&inode->i_lock);
+			return alias;
+		}
 		spin_unlock(&alias->d_lock);
 	}
 	spin_unlock(&inode->i_lock);
 
-	return alias;
+	return NULL;
 }
 
 /*

  parent reply	other threads:[~2017-08-02  3:08 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-02  3:06 [PATCH 0/6] dcache/namei fixes for lustre NeilBrown
2017-08-02  3:06 ` [PATCH 6/6] staging: lustre: llite: fix incorrect DCACHE_DISCONNECTED test NeilBrown
2017-08-02  3:06 ` [PATCH 3/6] staging: lustre: llite: remove directory-specific code from ll_find_alias() NeilBrown
2017-08-02  3:06 ` [PATCH 2/6] staging: lustre: llite: use d_splice_alias for directories NeilBrown
2017-08-02  3:06 ` NeilBrown [this message]
2017-08-02  3:06 ` [PATCH 1/6] staging: lustre: llite: handle DCACHE_PAR_LOOKUP in ll_dcompare NeilBrown
2017-08-02  3:06 ` [PATCH 5/6] staging: lustre: llite: refine ll_find_alias based on d_exact_alias NeilBrown
2017-08-20  2:58 ` [lustre-devel] [PATCH 0/6] dcache/namei fixes for lustre James Simmons
2017-10-20  0:39   ` NeilBrown
2017-10-24 21:50     ` James Simmons
2017-10-24 22:35       ` NeilBrown

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