handle the case where we try a multi-read that is completely beyond the end of file.

when a multi-read was completely beyond the end of file, this caused us to invoke the callback with a 'read-count' of <0  which the callback would treat as a failure.
This would then cause the callback to treat the data pointer as an error string and try to use it for nfs_set_error().
Since the data pointer was actually a real binary databuffer and not an error string this would cause the NFS error string to look like it contained garbage data.

In this case, where the multi-read fails to read any data at all since it if fully beyond end of file,  make sure to invoke the callback with a read-count of 0

diff --git a/lib/libnfs.c b/lib/libnfs.c
index 996b9880a91c232d8627b1470fa7b658046032d5..d1f4f0e87859d31666083a6eac2246d429238298 100644 (file)
--- a/lib/libnfs.c
+++ b/lib/libnfs.c
@@ -889,7 +889,11 @@ static void nfs_pread_mcb(struct rpc_context *rpc _U_, int status, void *command
        }
 
        data->nfsfh->offset = data->max_offset;
-       data->cb(data->max_offset - data->start_offset, nfs, data->buffer, data->private_data);
+       if (data->max_offset - data->start_offset >= 0) {
+               data->cb(data->max_offset - data->start_offset, nfs, data->buffer, data->private_data);
+       } else {
+               data->cb(0, nfs, data->buffer, data->private_data);
+       }
        free_nfs_cb_data(data);
        free(mdata);
 }