Return-Path: Received: from mail-vn0-f42.google.com ([209.85.216.42]:46695 "EHLO mail-vn0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752818AbbFLOEz (ORCPT ); Fri, 12 Jun 2015 10:04:55 -0400 Received: by vnbf7 with SMTP id f7so6132033vnb.13 for ; Fri, 12 Jun 2015 07:04:54 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <557AE2E7.1090908@gmail.com> References: <557AE2E7.1090908@gmail.com> Date: Fri, 12 Jun 2015 10:04:54 -0400 Message-ID: Subject: Re: [PATCH] nfs: Fix showing truncated fsid/dev in /proc/net/nfsfs/volumes From: Trond Myklebust To: Kinglong Mee Cc: "linux-nfs@vger.kernel.org" , David Howells Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Jun 12, 2015 at 9:47 AM, Kinglong Mee wrote: > A truncated fsid showing from /proc/fs/nfsfs/volumes as, > # cat /proc/fs/nfsfs/volumes > NV SERVER PORT DEV FSID FSC > v4 c0a80881 801 0:43 34931f044c2a439b no > > It should be as, > # cat /proc/fs/nfsfs/volumes > NV SERVER PORT DEV FSID FSC > v4 c0a80881 801 0:43 34931f044c2a439b:954c5d830fa4be8c no > > The max buffer length for storing "%llx:%llx" format should be > 16 + 1 + 16 + 1 = 34 (16 for %llx, 1 for ':', 1 for '\0'). > > Also, for storing "%u:%u" of MAJOR() and MINOR() should be > 8 + 1 + 3 + 1 = 13 (8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'). > > Signed-off-by: Kinglong Mee > --- > fs/nfs/client.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/fs/nfs/client.c b/fs/nfs/client.c > index 892aeff..873f194 100644 > --- a/fs/nfs/client.c > +++ b/fs/nfs/client.c > @@ -1364,27 +1364,28 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) > { > struct nfs_server *server; > struct nfs_client *clp; > - char dev[8], fsid[17]; > + char dev[13], fsid[34]; Could use a comment to explain why these particular sizes. > struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id); > > /* display header on line 1 */ > if (v == &nn->nfs_volume_list) { > - seq_puts(m, "NV SERVER PORT DEV FSID FSC\n"); > + seq_puts(m, "NV SERVER PORT DEV FSID" > + " FSC\n"); > return 0; > } > /* display one transport per line on subsequent lines */ > server = list_entry(v, struct nfs_server, master_link); > clp = server->nfs_client; > > - snprintf(dev, 8, "%u:%u", > + snprintf(dev, 13, "%u:%u", Is there any reason not to settle for using sizeof(dev) here? > MAJOR(server->s_dev), MINOR(server->s_dev)); > > - snprintf(fsid, 17, "%llx:%llx", > + snprintf(fsid, 34, "%llx:%llx", ditto > (unsigned long long) server->fsid.major, > (unsigned long long) server->fsid.minor); > > rcu_read_lock(); > - seq_printf(m, "v%u %s %s %-7s %-17s %s\n", > + seq_printf(m, "v%u %s %s %-12s %-33s %s\n", > clp->rpc_ops->version, > rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR), > rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT), > -- > 2.4.3 >