[SMB3][Multichannel] avoid confusing warning message on mount to Azure

[SMB3][Multichannel] avoid confusing warning message on mount to Azure

[Steve French]

[-- Attachment #1: Type: text/plain, Size: 1069 bytes --]

Mounts to Azure cause an unneeded warning message in dmesg
   "CIFS: VFS: parse_server_interfaces: incomplete interface info"

Azure rounds up the size (by 8 additional bytes, to a
16 byte boundary) of the structure returned on the query
of the server interfaces at mount time.  This is permissible
even though different than other servers so do not log a warning
if query network interfaces response is only rounded up by 8
bytes or fewer.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/smb2ops.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 3d914d7d0d11..22f1d8dc12b0 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -477,7 +477,8 @@ parse_server_interfaces(struct
network_interface_info_ioctl_rsp *buf,
  goto out;
  }

- if (bytes_left || p->Next)
+ /* Azure rounds the buffer size up 8, to a 16 byte boundary */
+ if ((bytes_left > 8) || p->Next)
  cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);


-- 
Thanks,

Steve

[-- Attachment #2: 0001-SMB3-avoid-confusing-warning-message-on-mount-to-Azu.patch --]
[-- Type: text/x-patch, Size: 1293 bytes --]

From ce86e35e88df69f2890ed2ab699e292c7390ef2c Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Tue, 8 Dec 2020 21:13:31 -0600
Subject: [PATCH] SMB3: avoid confusing warning message on mount to Azure

Mounts to Azure cause an unneeded warning message in dmesg
   "CIFS: VFS: parse_server_interfaces: incomplete interface info"

Azure rounds up the size (by 8 additional bytes, to a
16 byte boundary) of the structure returned on the query
of the server interfaces at mount time.  This is permissible
even though different than other servers so do not log a warning
if query network interfaces response is only rounded up by 8
bytes or fewer.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/smb2ops.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 3d914d7d0d11..22f1d8dc12b0 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -477,7 +477,8 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
 		goto out;
 	}
 
-	if (bytes_left || p->Next)
+	/* Azure rounds the buffer size up 8, to a 16 byte boundary */
+	if ((bytes_left > 8) || p->Next)
 		cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
 
 
-- 
2.27.0

Re: [SMB3][Multichannel] avoid confusing warning message on mount to Azure

[ronnie sahlberg]

Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

On Wed, Dec 9, 2020 at 1:22 PM Steve French <smfrench@gmail.com> wrote:
>
> Mounts to Azure cause an unneeded warning message in dmesg
>    "CIFS: VFS: parse_server_interfaces: incomplete interface info"
>
> Azure rounds up the size (by 8 additional bytes, to a
> 16 byte boundary) of the structure returned on the query
> of the server interfaces at mount time.  This is permissible
> even though different than other servers so do not log a warning
> if query network interfaces response is only rounded up by 8
> bytes or fewer.
>
> CC: Stable <stable@vger.kernel.org>
> Signed-off-by: Steve French <stfrench@microsoft.com>
> ---
>  fs/cifs/smb2ops.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 3d914d7d0d11..22f1d8dc12b0 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -477,7 +477,8 @@ parse_server_interfaces(struct
> network_interface_info_ioctl_rsp *buf,
>   goto out;
>   }
>
> - if (bytes_left || p->Next)
> + /* Azure rounds the buffer size up 8, to a 16 byte boundary */
> + if ((bytes_left > 8) || p->Next)
>   cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
>
>
> --
> Thanks,
>
> Steve

Re: [SMB3][Multichannel] avoid confusing warning message on mount to Azure

[Tom Talpey]

Why not just delete the splat? It isn't causing a failure, and
appears to be legal protocol behavior.

On 12/8/2020 10:21 PM, Steve French wrote:
> Mounts to Azure cause an unneeded warning message in dmesg
>     "CIFS: VFS: parse_server_interfaces: incomplete interface info"
> 
> Azure rounds up the size (by 8 additional bytes, to a
> 16 byte boundary) of the structure returned on the query
> of the server interfaces at mount time.  This is permissible
> even though different than other servers so do not log a warning
> if query network interfaces response is only rounded up by 8
> bytes or fewer.
> 
> CC: Stable <stable@vger.kernel.org>
> Signed-off-by: Steve French <stfrench@microsoft.com>
> ---
>   fs/cifs/smb2ops.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 3d914d7d0d11..22f1d8dc12b0 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -477,7 +477,8 @@ parse_server_interfaces(struct
> network_interface_info_ioctl_rsp *buf,
>    goto out;
>    }
> 
> - if (bytes_left || p->Next)
> + /* Azure rounds the buffer size up 8, to a 16 byte boundary */
> + if ((bytes_left > 8) || p->Next)
>    cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);
> 
>