commit 64cfca85bacde54caa64e0ab855c48734894fa37
author Trond Myklebust <trond.myklebust@hammerspace.com> Thu Feb 24 10:59:37 2022 -0500
committer Trond Myklebust <trond.myklebust@hammerspace.com> Mon Feb 28 10:11:32 2022 -0500
tree 0ff9768007b09b52f98985cc593de36750db7afc
parent b38e09b9b613ee608c87bc00979db891ee9f0538

NFS: Return valid errors from nfs2/3_decode_dirent()

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>

fs/nfs/nfs3xdr.c

diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 54a1d21..7ab60ad 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1967,7 +1967,6 @@ int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
 		       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 *xdr, struct nfs_entry *entry,
 
 	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 *xdr, struct nfs_entry *entry,
 		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 *xdr, struct nfs_entry *entry,
 			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 *xdr, struct nfs_entry *entry,
 	entry->cookie = new_cookie;
 
 	return 0;
-
-out_truncated:
-	dprintk("NFS: directory entry contains invalid file handle\n");
-	*entry = old;
-	return -EAGAIN;
 }
 
 /*