[PATCH 29/34] union-mount: Return files found in lower layers in __union_lookup()

[Valerie Aurora <vaurora@redhat.com>]

If we find a file during union lookup, don't look in any lower layers
and replace the topmost path with the file's path.

Signed-off-by: Valerie Aurora <vaurora@redhat.com>
---
 fs/namei.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index f6ad8b3..c6696d8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -798,11 +798,34 @@ static int __lookup_union(struct nameidata *nd, struct qstr *name,
 			continue;
 		}
 
+		/*
+		 * Files block everything below them.  Special case:
+		 * If we find a file below a directory (which makes no
+		 * sense), just ignore the file and return the
+		 * directory above it.
+		 */
+		if (!S_ISDIR(lower.dentry->d_inode->i_mode)) {
+			if (topmost->dentry->d_inode &&
+			    S_ISDIR(topmost->dentry->d_inode->i_mode))
+				goto out_lookup_done;
+			goto out_found_file;
+		}
+
 		/* XXX - do nothing, more in later patches */
 		path_put(&lower);
 	}
 	return 0;
 
+out_found_file:
+	/*
+	 * Swap out the positive lower dentry with the negative upper
+	 * dentry for this file.  Note that the matching mntput() is done
+	 * in link_path_walk().
+	 */
+	dput(topmost->dentry);
+	*topmost = lower;
+	return 0;
+
 out_lookup_done:
 	path_put(&lower);
 	return 0;
-- 
1.6.3.3