linux-kernel - Re: [PATCH 11/13] smb: introduce struct create_posix_ctxt

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Message-ID: <CAKYAXd8ANQKPbzzxfhp1eiH5my-uoZvr-x0iRYaqu=+BnV0P8A@mail.gmail.com>
Date: Wed, 10 Dec 2025 09:31:26 +0900
From: Namjae Jeon <linkinjeon@...nel.org>
To: ChenXiaoSong <chenxiaosong.chenxiaosong@...ux.dev>
Cc: sfrench@...ba.org, smfrench@...il.com, linkinjeon@...ba.org, 
	linux-cifs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	liuzhengyuan@...inos.cn, huhai@...inos.cn, liuyun01@...inos.cn, 
	ZhangGuoDong <zhangguodong@...inos.cn>, ChenXiaoSong <chenxiaosong@...inos.cn>
Subject: Re: [PATCH 11/13] smb: introduce struct create_posix_ctxt_rsp

On Wed, Dec 10, 2025 at 9:13 AM ChenXiaoSong
<chenxiaosong.chenxiaosong@...ux.dev> wrote:
>
> Hi Namjae,
>
> The `create_posix_rsp` structures on the client and server sides differ,
> but they share a common part, and only this common part is defined in
> POSIX‑SMB2 2.2.14.2.16.
I agree with moving create_posix_rsp struct to common, but doing it
partially feels forced and unnatural.
>
> /*
>   * [POSIX-SMB2] SMB3 POSIX Extensions
>   * Link:
> https://gitlab.com/samba-team/smb3-posix-spec/-/blob/master/smb3_posix_extensions.md
>   */
>
> Thanks,
> ChenXiaoSong.
>
> On 12/10/25 7:45 AM, Namjae Jeon wrote:
> > On Tue, Dec 9, 2025 at 10:12 AM <chenxiaosong.chenxiaosong@...ux.dev> wrote:
> >>
> >> From: ZhangGuoDong <zhangguodong@...inos.cn>
> >>
> >> Modify the following places:
> >>
> >>    - introduce new struct create_posix_ctxt_rsp
> >>    - some fields in "struct create_posix_rsp" -> "struct create_posix_ctxt_rsp"
> >>    - create_posix_rsp_buf(): offsetof(..., nlink) -> offsetof(..., ctxt_rsp)
> > I don't know why we need to add a new create_posix_ctxt_rsp struct.
> >>
> >> Co-developed-by: ChenXiaoSong <chenxiaosong@...inos.cn>
> >> Signed-off-by: ChenXiaoSong <chenxiaosong@...inos.cn>
> >> Signed-off-by: ZhangGuoDong <zhangguodong@...inos.cn>
> >> ---
> >>   fs/smb/client/smb2pdu.c |  9 +++++----
> >>   fs/smb/client/smb2pdu.h |  6 ++----
> >>   fs/smb/common/smb2pdu.h | 18 ++++++++++++++++++
> >>   fs/smb/server/oplock.c  |  8 ++++----
> >>   fs/smb/server/smb2pdu.h |  6 ++----
> >>   5 files changed, 31 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
> >> index ef2c6ac500f7..ec0f83db5591 100644
> >> --- a/fs/smb/client/smb2pdu.c
> >> +++ b/fs/smb/client/smb2pdu.c
> >> @@ -2298,9 +2298,9 @@ parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info,
> >>
> >>          memset(posix, 0, sizeof(*posix));
> >>
> >> -       posix->nlink = le32_to_cpu(*(__le32 *)(beg + 0));
> >> -       posix->reparse_tag = le32_to_cpu(*(__le32 *)(beg + 4));
> >> -       posix->mode = le32_to_cpu(*(__le32 *)(beg + 8));
> >> +       posix->ctxt_rsp.nlink = le32_to_cpu(*(__le32 *)(beg + 0));
> >> +       posix->ctxt_rsp.reparse_tag = le32_to_cpu(*(__le32 *)(beg + 4));
> >> +       posix->ctxt_rsp.mode = le32_to_cpu(*(__le32 *)(beg + 8));
> >>
> >>          sid = beg + 12;
> >>          sid_len = posix_info_sid_size(sid, end);
> >> @@ -2319,7 +2319,8 @@ parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info,
> >>          memcpy(&posix->group, sid, sid_len);
> >>
> >>          cifs_dbg(FYI, "nlink=%d mode=%o reparse_tag=%x\n",
> >> -                posix->nlink, posix->mode, posix->reparse_tag);
> >> +                posix->ctxt_rsp.nlink, posix->ctxt_rsp.mode,
> >> +                posix->ctxt_rsp.reparse_tag);
> >>   }
> >>
> >>   int smb2_parse_contexts(struct TCP_Server_Info *server,
> >> diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
> >> index 78bb99f29d38..4928fb620233 100644
> >> --- a/fs/smb/client/smb2pdu.h
> >> +++ b/fs/smb/client/smb2pdu.h
> >> @@ -251,11 +251,9 @@ struct smb2_file_id_extd_directory_info {
> >>
> >>   extern char smb2_padding[7];
> >>
> >> -/* equivalent of the contents of SMB3.1.1 POSIX open context response */
> >> +/* See POSIX-SMB2 2.2.14.2.16 */
> >>   struct create_posix_rsp {
> >> -       u32 nlink;
> >> -       u32 reparse_tag;
> >> -       u32 mode;
> >> +       struct create_posix_ctxt_rsp ctxt_rsp;
> >>          struct smb_sid owner; /* var-sized on the wire */
> >>          struct smb_sid group; /* var-sized on the wire */
> >>   } __packed;
> >> diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h
> >> index 72f2cfc47da8..698ab9d7d16b 100644
> >> --- a/fs/smb/common/smb2pdu.h
> >> +++ b/fs/smb/common/smb2pdu.h
> >> @@ -1814,4 +1814,22 @@ typedef struct smb_negotiate_req {
> >>          unsigned char DialectsArray[];
> >>   } __packed SMB_NEGOTIATE_REQ;
> >>
> >> +
> >> +/*
> >> + * [POSIX-SMB2] SMB3 POSIX Extensions
> >> + * Link: https://gitlab.com/samba-team/smb3-posix-spec/-/blob/master/smb3_posix_extensions.md
> >> + */
> >> +
> >> +/*
> >> + * SMB2_CREATE_POSIX_CONTEXT Response
> >> + * See POSIX-SMB2 2.2.14.2.16
> >> + */
> >> +struct create_posix_ctxt_rsp {
> >> +       __le32 nlink;
> >> +       __le32 reparse_tag;
> >> +       __le32 mode;
> >> +       // var sized owner SID
> >> +       // var sized group SID
> >> +} __packed;
> >> +
> >>   #endif                         /* _COMMON_SMB2PDU_H */
> >> diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c
> >> index 1f07ebf431d7..8658402ff893 100644
> >> --- a/fs/smb/server/oplock.c
> >> +++ b/fs/smb/server/oplock.c
> >> @@ -1703,7 +1703,7 @@ void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp)
> >>          buf = (struct create_posix_rsp *)cc;
> >>          memset(buf, 0, sizeof(struct create_posix_rsp));
> >>          buf->ccontext.DataOffset = cpu_to_le16(offsetof
> >> -                       (struct create_posix_rsp, nlink));
> >> +                       (struct create_posix_rsp, ctxt_rsp));
> >>          /*
> >>           * DataLength = nlink(4) + reparse_tag(4) + mode(4) +
> >>           * domain sid(28) + unix group sid(16).
> >> @@ -1730,9 +1730,9 @@ void create_posix_rsp_buf(char *cc, struct ksmbd_file *fp)
> >>          buf->Name[14] = 0xCD;
> >>          buf->Name[15] = 0x7C;
> >>
> >> -       buf->nlink = cpu_to_le32(inode->i_nlink);
> >> -       buf->reparse_tag = cpu_to_le32(fp->volatile_id);
> >> -       buf->mode = cpu_to_le32(inode->i_mode & 0777);
> >> +       buf->ctxt_rsp.nlink = cpu_to_le32(inode->i_nlink);
> >> +       buf->ctxt_rsp.reparse_tag = cpu_to_le32(fp->volatile_id);
> >> +       buf->ctxt_rsp.mode = cpu_to_le32(inode->i_mode & 0777);
> >>          /*
> >>           * SidBuffer(44) contain two sids(Domain sid(28), UNIX group sid(16)).
> >>           * Domain sid(28) = revision(1) + num_subauth(1) + authority(6) +
> >> diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h
> >> index 66cdc8e4a648..09311a9eb1de 100644
> >> --- a/fs/smb/server/smb2pdu.h
> >> +++ b/fs/smb/server/smb2pdu.h
> >> @@ -83,13 +83,11 @@ struct create_durable_rsp {
> >>          } Data;
> >>   } __packed;
> >>
> >> -/* equivalent of the contents of SMB3.1.1 POSIX open context response */
> >> +/* See POSIX-SMB2 2.2.14.2.16 */
> >>   struct create_posix_rsp {
> >>          struct create_context_hdr ccontext;
> >>          __u8    Name[16];
> >> -       __le32 nlink;
> >> -       __le32 reparse_tag;
> >> -       __le32 mode;
> >> +       struct create_posix_ctxt_rsp ctxt_rsp;
> >>          /* SidBuffer contain two sids(Domain sid(28), UNIX group sid(16)) */
> >>          u8 SidBuffer[44];
> >>   } __packed;
> >> --
> >> 2.43.0
> >>
>