[PATCH] ubifs: Fix regression in ubifs_readdir()

[Richard Weinberger]

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 at axentia.se>
Tested-by: Peter Rosin <peda at axentia.se>
Reported-by: Ralph Sennhauser <ralph.sennhauser at gmail.com>
Fixes: c83ed4c9dbb35 ("ubifs: Abort readdir upon error")
Cc: stable at vger.kernel.org
Signed-off-by: Richard Weinberger <richard at nod.at>
---
 fs/ubifs/dir.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index bd4a5e8ce441..ca16c5d7bab1 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -543,6 +543,14 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx)
 
 	if (err != -ENOENT)
 		ubifs_err(c, "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;
+
 
 	/* 2 is a special value indicating that there are no more direntries */
 	ctx->pos = 2;
-- 
2.7.3