[PATCH 3.16 180/306] ubifs: Fix regression in ubifs_readdir()

[Ben Hutchings]

3.16.40-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Richard Weinberger <richard@xxxxxx>

commit a00052a296e54205cf238c75bd98d17d5d02a6db upstream.

Commit c83ed4c9dbb35 ("ubifs: Abort readdir upon error") broke
overlayfs support because the fix exposed an internal error
code to VFS.

Reported-by: Peter Rosin <peda@xxxxxxxxxx>
Tested-by: Peter Rosin <peda@xxxxxxxxxx>
Reported-by: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
Tested-by: Ralph Sennhauser <ralph.sennhauser@xxxxxxxxx>
Fixes: c83ed4c9dbb35 ("ubifs: Abort readdir upon error")
Signed-off-by: Richard Weinberger <richard@xxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/ubifs/dir.c | 8 ++++++++
 1 file changed, 8 insertions(+)

--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -448,6 +448,14 @@ static int ubifs_readdir(struct file *fi
 out:
 	if (err != -ENOENT)
 		ubifs_err("cannot find next direntry, error %d", err);
+	else
+		/*
+		 * -ENOENT is a non-fatal error in this context, the TNC uses
+		 * it to indicate that the cursor moved past the current directory
+		 * and readdir() has to stop.
+		 */
+		err = 0;
+
 
 	kfree(file->private_data);
 	file->private_data = NULL;