nfsd: return RESOURCE not GARBAGE_ARGS on too many ops
A client that sends more than a hundred ops in a single compound
currently gets an rpc-level GARBAGE_ARGS error.
It would be more helpful to return NFS4ERR_RESOURCE, since that gives
the client a better idea how to recover (for example by splitting up the
compound into smaller compounds).
This is all a bit academic since we've never actually seen a reason for
clients to send such long compounds, but we may as well fix it.
While we're there, just use NFSD4_MAX_OPS_PER_COMPOUND == 16, the
constant we already use in the 4.1 case, instead of hard-coding 100.
Chances anyone actually uses even 16 ops per compound are small enough
that I think there's a neglible risk or any regression.
This fixes pynfs test COMP6.
Reported-by: "Lu, Xinyu" <luxy.fnst@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 2c61c6b..5dcd7cb 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1918,8 +1918,13 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
if (argp->taglen > NFSD4_MAX_TAGLEN)
goto xdr_error;
- if (argp->opcnt > 100)
- goto xdr_error;
+ /*
+ * NFS4ERR_RESOURCE is a more helpful error than GARBAGE_ARGS
+ * here, so we return success at the xdr level so that
+ * nfsd4_proc can handle this is an NFS-level error.
+ */
+ if (argp->opcnt > NFSD_MAX_OPS_PER_COMPOUND)
+ return 0;
if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops), GFP_KERNEL);
