[PATCH 10/23] vfs: Teach do_path_lookup to use file_hotplug_lock

["Eric W. Biederman" <ebiederm@xmission.com>]

From: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
 fs/namei.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 5472ed0..c4c6575 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1049,23 +1049,30 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct namei
 		if (!file)
 			goto out_fail;
 
+		retval = -EIO;
+		if (!file_hotplug_read_trylock(file))
+			goto fput_fail;
+
 		dentry = file->f_path.dentry;
 
 		retval = -ENOTDIR;
 		if (!S_ISDIR(dentry->d_inode->i_mode))
-			goto fput_fail;
+			goto unlock_fail;
 
 		retval = file_permission(file, MAY_EXEC);
 		if (retval)
-			goto fput_fail;
+			goto unlock_fail;
 
 		nd->path = file->f_path;
 		path_get(&file->f_path);
 
+		file_hotplug_read_unlock(file);
 		fput_light(file, fput_needed);
 	}
 	return 0;
 
+unlock_fail:
+	file_hotplug_read_unlock(file);
 fput_fail:
 	fput_light(file, fput_needed);
 out_fail:
-- 
1.6.3.1.54.g99dd.dirty