Return-Path: Received: from mail-pa0-f68.google.com ([209.85.220.68]:35637 "EHLO mail-pa0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330AbbFMA6x (ORCPT ); Fri, 12 Jun 2015 20:58:53 -0400 Received: by pabli10 with SMTP id li10so9344012pab.2 for ; Fri, 12 Jun 2015 17:58:53 -0700 (PDT) Message-ID: <557B8042.8010208@gmail.com> Date: Sat, 13 Jun 2015 08:58:42 +0800 From: Kinglong Mee MIME-Version: 1.0 To: Trond Myklebust CC: "linux-nfs@vger.kernel.org" , David Howells Subject: Re: [PATCH] nfs: Fix showing truncated fsid/dev in /proc/net/nfsfs/volumes References: <557AE2E7.1090908@gmail.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 6/12/2015 10:04 PM, Trond Myklebust wrote: > 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'). Here is the comments for why buffer size is 13 and 34. >> >> 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? No, I just modify it as before. I will update it as using sizeof(dev) in the new version. thanks, Kinglong Mee > >> 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 >> >