linux-kernel - [PATCH 07/15] reconnect_one(): use lookup_one_len

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Message-Id: <1460768127-31822-7-git-send-email-viro@ZenIV.linux.org.uk>
Date:	Sat, 16 Apr 2016 01:55:19 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 07/15] reconnect_one(): use lookup_one_len_unlocked()

From: Al Viro <viro@...iv.linux.org.uk>

... and explain the non-obvious logics in case when lookup yields
a different dentry.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/exportfs/expfs.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index c46f1a1..402c5ca 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -143,14 +143,18 @@ static struct dentry *reconnect_one(struct vfsmount *mnt,
 	if (err)
 		goto out_err;
 	dprintk("%s: found name: %s\n", __func__, nbuf);
-	inode_lock(parent->d_inode);
-	tmp = lookup_one_len(nbuf, parent, strlen(nbuf));
-	inode_unlock(parent->d_inode);
+	tmp = lookup_one_len_unlocked(nbuf, parent, strlen(nbuf));
 	if (IS_ERR(tmp)) {
 		dprintk("%s: lookup failed: %d\n", __func__, PTR_ERR(tmp));
 		goto out_err;
 	}
 	if (tmp != dentry) {
+		/*
+		 * Somebody has renamed it since exportfs_get_name();
+		 * great, since it could've only been renamed if it
+		 * got looked up and thus connected, and it would
+		 * remain connected afterwards.  We are done.
+		 */
 		dput(tmp);
 		goto out_reconnected;
 	}
-- 
2.8.0.rc3