Re: Regression caused by commit c83ed4c9dbb3 "ubifs: Abort readdir on error"

[Richard Weinberger]

Peter,

On 25.10.2016 22:09, Richard Weinberger wrote:
>> /bin/mkdir -p /mnt/ovl/ovl
>> /bin/mkdir -p /mnt/ovl/work
>> # with c83ed4c9dbb3, the following mount fails with
>> # mount: mounting overlay on /mnt/merge failed: No such file or directory
>> /bin/mount -t overlay -o lowerdir=/,upperdir=/mnt/ovl/ovl,workdir=/mnt/ovl/work overlay /mnt/merge
> 
> Uhhhh! Thanks for catching this.
> I think I know what is going on, the fix exposes now internal UBIFS return codes to VFS.
> Let me prepare a fix.

Does the attached patch cure the issue?

Thanks,
//richard
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;