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 |   20 ++++++--------------
 2 files changed, 7 insertions(+), 15 deletions(-)

--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -938,7 +938,7 @@ 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
@@ -1948,7 +1948,6 @@ out_status:
 int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
 		       int plus)
 {
-	struct nfs_entry old = *entry;
 	__be32 *p;
 	int error;
 
@@ -1967,16 +1966,16 @@ 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;
 
 	entry->prev_cookie = entry->cookie;
 	error = decode_cookie3(xdr, &entry->cookie);
 	if (unlikely(error))
-		return error;
+		return -EAGAIN;
 
 	entry->d_type = DT_UNKNOWN;
 
@@ -1984,7 +1983,7 @@ int nfs3_decode_dirent(struct xdr_stream
 		entry->fattr->valid = 0;
 		error = decode_post_op_attr(xdr, entry->fattr);
 		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);
 
@@ -1999,11 +1998,8 @@ int nfs3_decode_dirent(struct xdr_stream
 			goto out_overflow;
 		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);
 	}
@@ -2013,10 +2009,6 @@ int nfs3_decode_dirent(struct xdr_stream
 out_overflow:
 	print_overflow_msg(__func__, xdr);
 	return -EAGAIN;
-out_truncated:
-	dprintk("NFS: directory entry contains invalid file handle\n");
-	*entry = old;
-	return -EAGAIN;
 }
 
 /*