NFSv4: OPEN must handle the NFS4ERR_IO return code correctly
commit c7848f69ec4a8c03732cde5c949bd2aa711a9f4b upstream.
decode_op_hdr() cannot distinguish between an XDR decoding error and
the perfectly valid errorcode NFS4ERR_IO. This is normally not a
problem, but for the particular case of OPEN, we need to be able
to increment the NFSv4 open sequence id when the server returns
a valid response.
Reported-by: J Bruce Fields <bfields@fieldses.org>
Link: http://lkml.kernel.org/r/20131204210356.GA19452@fieldses.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index c8ac9a1..8cf722f 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -2955,7 +2955,8 @@
return -EIO;
}
-static int decode_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
+static bool __decode_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected,
+ int *nfs_retval)
{
__be32 *p;
uint32_t opnum;
@@ -2965,19 +2966,32 @@
if (unlikely(!p))
goto out_overflow;
opnum = be32_to_cpup(p++);
- if (opnum != expected) {
- dprintk("nfs: Server returned operation"
- " %d but we issued a request for %d\n",
- opnum, expected);
- return -EIO;
- }
+ if (unlikely(opnum != expected))
+ goto out_bad_operation;
nfserr = be32_to_cpup(p);
- if (nfserr != NFS_OK)
- return nfs4_stat_to_errno(nfserr);
- return 0;
+ if (nfserr == NFS_OK)
+ *nfs_retval = 0;
+ else
+ *nfs_retval = nfs4_stat_to_errno(nfserr);
+ return true;
+out_bad_operation:
+ dprintk("nfs: Server returned operation"
+ " %d but we issued a request for %d\n",
+ opnum, expected);
+ *nfs_retval = -EREMOTEIO;
+ return false;
out_overflow:
print_overflow_msg(__func__, xdr);
- return -EIO;
+ *nfs_retval = -EIO;
+ return false;
+}
+
+static int decode_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
+{
+ int retval;
+
+ __decode_op_hdr(xdr, expected, &retval);
+ return retval;
}
/* Dummy routine */
@@ -4680,11 +4694,12 @@
uint32_t savewords, bmlen, i;
int status;
- status = decode_op_hdr(xdr, OP_OPEN);
- if (status != -EIO)
- nfs_increment_open_seqid(status, res->seqid);
- if (!status)
- status = decode_stateid(xdr, &res->stateid);
+ if (!__decode_op_hdr(xdr, OP_OPEN, &status))
+ return status;
+ nfs_increment_open_seqid(status, res->seqid);
+ if (status)
+ return status;
+ status = decode_stateid(xdr, &res->stateid);
if (unlikely(status))
return status;