From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 24 Feb 2022 10:59:37 -0500
Subject: [PATCH] NFS: Return valid errors from nfs2/3_decode_dirent()
Git-commit: 64cfca85bacde54caa64e0ab855c48734894fa37
Patch-mainline: v5.18
References: git-fixes

Valid return values for decode_dirent() callback functions are:
 0: Success
 -EBADCOOKIE: End of directory
 -EAGAIN: End of xdr_stream

All errors need to map into one of those three values.

Fixes: 573c4e1ef53a ("NFS: Simplify ->decode_dirent() calling sequence")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/nfs2xdr.c |    2 +-
 fs/nfs/nfs3xdr.c |   21 ++++++---------------
 2 files changed, 7 insertions(+), 16 deletions(-)

--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -949,7 +949,7 @@ int nfs2_decode_dirent(struct xdr_stream
 
 	error = decode_filename_inline(xdr, &entry->name, &entry->len);
 	if (unlikely(error))
-		return error;
+		return -EAGAIN;
 
 	/*
 	 * The type (size and byte order) of nfscookie isn't defined in
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1967,7 +1967,6 @@ int nfs3_decode_dirent(struct xdr_stream
 		       bool plus)
 {
 	struct user_namespace *userns = rpc_userns(entry->server->client);
-	struct nfs_entry old = *entry;
 	__be32 *p;
 	int error;
 	u64 new_cookie;
@@ -1987,15 +1986,15 @@ int nfs3_decode_dirent(struct xdr_stream
 
 	error = decode_fileid3(xdr, &entry->ino);
 	if (unlikely(error))
-		return error;
+		return -EAGAIN;
 
 	error = decode_inline_filename3(xdr, &entry->name, &entry->len);
 	if (unlikely(error))
-		return error;
+		return -EAGAIN;
 
 	error = decode_cookie3(xdr, &new_cookie);
 	if (unlikely(error))
-		return error;
+		return -EAGAIN;
 
 	entry->d_type = DT_UNKNOWN;
 
@@ -2003,7 +2002,7 @@ int nfs3_decode_dirent(struct xdr_stream
 		entry->fattr->valid = 0;
 		error = decode_post_op_attr(xdr, entry->fattr, userns);
 		if (unlikely(error))
-			return error;
+			return -EAGAIN;
 		if (entry->fattr->valid & NFS_ATTR_FATTR_V3)
 			entry->d_type = nfs_umode_to_dtype(entry->fattr->mode);
 
@@ -2018,11 +2017,8 @@ int nfs3_decode_dirent(struct xdr_stream
 			return -EAGAIN;
 		if (*p != xdr_zero) {
 			error = decode_nfs_fh3(xdr, entry->fh);
-			if (unlikely(error)) {
-				if (error == -E2BIG)
-					goto out_truncated;
-				return error;
-			}
+			if (unlikely(error))
+				return -EAGAIN;
 		} else
 			zero_nfs_fh3(entry->fh);
 	}
@@ -2031,11 +2027,6 @@ int nfs3_decode_dirent(struct xdr_stream
 	entry->cookie = new_cookie;
 
 	return 0;
-
-out_truncated:
-	dprintk("NFS: directory entry contains invalid file handle\n");
-	*entry = old;
-	return -EAGAIN;
 }
 
 /*