2015-06-12 13:47:33

by Kinglong Mee

Subject: [PATCH] nfs: Fix showing truncated fsid/dev in /proc/net/nfsfs/volumes

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 <[email protected]>
---
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];
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",
MAJOR(server->s_dev), MINOR(server->s_dev));

- snprintf(fsid, 17, "%llx:%llx",
+ snprintf(fsid, 34, "%llx:%llx",
(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

2015-06-12 14:04:55

by Trond Myklebust

Subject: Re: [PATCH] nfs: Fix showing truncated fsid/dev in /proc/net/nfsfs/volumes

On Fri, Jun 12, 2015 at 9:47 AM, Kinglong Mee <[email protected]> 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 <[email protected]>
> ---
> 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
>

2015-06-13 00:58:53

by Kinglong Mee

Subject: Re: [PATCH] nfs: Fix showing truncated fsid/dev in /proc/net/nfsfs/volumes

On 6/12/2015 10:04 PM, Trond Myklebust wrote:
> On Fri, Jun 12, 2015 at 9:47 AM, Kinglong Mee <[email protected]> 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 <[email protected]>
>> ---
>> 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
>>
>

2015-06-13 02:07:06

by Kinglong Mee

Subject: [PATCH v2] nfs: Fix showing truncated fsid/dev in, /proc/net/nfsfs/volumes

A truncated fsid showing from /proc/fs/nfsfs/volumes as,
NV SERVER PORT DEV FSID FSC
v4 c0a80881 801 0:43 34931f044c2a439b no

It should be as,
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').

v2, add comments for dev/fsid buffer and use sizeof in snprintf.

Signed-off-by: Kinglong Mee <[email protected]>
---
fs/nfs/client.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 892aeff..1e37491 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1364,27 +1364,29 @@ 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]; // 8 for 2^24, 1 for ':', 3 for 2^8, 1 for '\0'
+ char fsid[34]; // 2 * 16 for %llx, 1 for ':', 1 for '\0'
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, sizeof(dev), "%u:%u",
MAJOR(server->s_dev), MINOR(server->s_dev));

- snprintf(fsid, 17, "%llx:%llx",
+ snprintf(fsid, sizeof(fsid), "%llx:%llx",
(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