Improve performance of POSIX open - request query disk id open context
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Message ID CAH2r5mtb_g1Hx4UPB+5XpSY3Ew_fn=bdjLnpRD=ZQymJxrUw0g@mail.gmail.com
State New
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  • Improve performance of POSIX open - request query disk id open context
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Commit Message

Steve French July 6, 2019, 6:13 a.m. UTC
We can cut the number of roundtrips on open (may also
help some rename cases as well) by returning the inode
number in the SMB2 open request itself instead of
querying it afterwards via a query FILE_INTERNAL_INFO.
This should significantly improve the performance of
posix open.

Add SMB2_CREATE_QUERY_ON_DISK_ID create context request
on open calls so that when server supports this we
can save a roundtrip for QUERY_INFO on every open.

Follow on patch will add the response processing for
SMB2_CREATE_QUERY_ON_DISK_ID context and optimize
smb2_open_file to avoid the extra network roundtrip
on every posix open. This patch adds the context on
SMB2/SMB3 open requests.

Comments

Pavel Shilovsky July 6, 2019, 4:34 p.m. UTC | #1
Good idea! See some comments below.

When adding new context, the following defines need to be changed:

689 /*
690  * Maximum size of a SMB2_CREATE response is 64 (smb2 header) +
691  * 88 (fixed part of create response) + 520 (path) + 150 (contexts) +
692  * 2 bytes of padding.
693  */
694 #define MAX_SMB2_CREATE_RESPONSE_SIZE 824

and

657 /*
658  * Maximum number of iovs we need for an open/create request.
659  * [0] : struct smb2_create_req
660  * [1] : path
661  * [2] : lease context
662  * [3] : durable context
663  * [4] : posix context
664  * [5] : time warp context
665  * [6] : compound padding
666  */
667 #define SMB2_CREATE_IOV_SIZE 7

+       if (n_iov > 2) {
+               struct create_context *ccontext =
+                       (struct create_context *)iov[n_iov-1].iov_base;
+               ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
+       }
+       add_query_id_context(iov, &n_iov);

I think we should add a check if iov has enough capacity to keep all
the contexts. Right now it will oops if it wasn't allocated right in
the upper layer.

In general, I think having a complete patch that adds the whole
functionality is better for future git bisect and looks more logical
instead of breaking such small features into parts.

Best regards,
Pavel Shilovskiy

пт, 5 июл. 2019 г. в 23:14, Steve French via samba-technical
<samba-technical@lists.samba.org>:
>
> We can cut the number of roundtrips on open (may also
> help some rename cases as well) by returning the inode
> number in the SMB2 open request itself instead of
> querying it afterwards via a query FILE_INTERNAL_INFO.
> This should significantly improve the performance of
> posix open.
>
> Add SMB2_CREATE_QUERY_ON_DISK_ID create context request
> on open calls so that when server supports this we
> can save a roundtrip for QUERY_INFO on every open.
>
> Follow on patch will add the response processing for
> SMB2_CREATE_QUERY_ON_DISK_ID context and optimize
> smb2_open_file to avoid the extra network roundtrip
> on every posix open. This patch adds the context on
> SMB2/SMB3 open requests.
>
> --
> Thanks,
>
> Steve
Steve French July 6, 2019, 7:43 p.m. UTC | #2
minor updates to incorporate Pavel's suggestions


On Sat, Jul 6, 2019 at 11:34 AM Pavel Shilovsky
<pavel.shilovsky@gmail.com> wrote:
>
> Good idea! See some comments below.
>
> When adding new context, the following defines need to be changed:
>
> 689 /*
> 690  * Maximum size of a SMB2_CREATE response is 64 (smb2 header) +
> 691  * 88 (fixed part of create response) + 520 (path) + 150 (contexts) +
> 692  * 2 bytes of padding.
> 693  */
> 694 #define MAX_SMB2_CREATE_RESPONSE_SIZE 824
>
> and
>
> 657 /*
> 658  * Maximum number of iovs we need for an open/create request.
> 659  * [0] : struct smb2_create_req
> 660  * [1] : path
> 661  * [2] : lease context
> 662  * [3] : durable context
> 663  * [4] : posix context
> 664  * [5] : time warp context
> 665  * [6] : compound padding
> 666  */
> 667 #define SMB2_CREATE_IOV_SIZE 7
>
> +       if (n_iov > 2) {
> +               struct create_context *ccontext =
> +                       (struct create_context *)iov[n_iov-1].iov_base;
> +               ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
> +       }
> +       add_query_id_context(iov, &n_iov);
>
> I think we should add a check if iov has enough capacity to keep all
> the contexts. Right now it will oops if it wasn't allocated right in
> the upper layer.
>
> In general, I think having a complete patch that adds the whole
> functionality is better for future git bisect and looks more logical
> instead of breaking such small features into parts.
>
> Best regards,
> Pavel Shilovskiy
>
> пт, 5 июл. 2019 г. в 23:14, Steve French via samba-technical
> <samba-technical@lists.samba.org>:
> >
> > We can cut the number of roundtrips on open (may also
> > help some rename cases as well) by returning the inode
> > number in the SMB2 open request itself instead of
> > querying it afterwards via a query FILE_INTERNAL_INFO.
> > This should significantly improve the performance of
> > posix open.
> >
> > Add SMB2_CREATE_QUERY_ON_DISK_ID create context request
> > on open calls so that when server supports this we
> > can save a roundtrip for QUERY_INFO on every open.
> >
> > Follow on patch will add the response processing for
> > SMB2_CREATE_QUERY_ON_DISK_ID context and optimize
> > smb2_open_file to avoid the extra network roundtrip
> > on every posix open. This patch adds the context on
> > SMB2/SMB3 open requests.
> >
> > --
> > Thanks,
> >
> > Steve

Patch
diff mbox series

From eb91a7da9d286c46bcaf30c9d8bd9ca977ad9832 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Sat, 6 Jul 2019 01:03:07 -0500
Subject: [PATCH] SMB3: query inode number on open via create context

We can cut the number of roundtrips on open (may also
help some rename cases as well) by returning the inode
number in the SMB2 open request itself instead of
querying it afterwards via a query FILE_INTERNAL_INFO.
This should significantly improve the performance of
posix open.

Add SMB2_CREATE_QUERY_ON_DISK_ID create context request
on open calls so that when server supports this we
can save a roundtrip for QUERY_INFO on every open.

Follow on patch will add the response processing for
SMB2_CREATE_QUERY_ON_DISK_ID context and optimize
smb2_open_file to avoid the extra network roundtrip
on every posix open. This patch adds the context on
SMB2/SMB3 open requests.

Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/smb2pdu.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 fs/cifs/smb2pdu.h |  6 ++++++
 2 files changed, 54 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 34d5397a1989..f58e4dc3987b 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2118,6 +2118,48 @@  add_twarp_context(struct kvec *iov, unsigned int *num_iovec, __u64 timewarp)
 	return 0;
 }
 
+static struct crt_query_id_ctxt *
+create_query_id_buf(void)
+{
+	struct crt_query_id_ctxt *buf;
+
+	buf = kzalloc(sizeof(struct crt_query_id_ctxt), GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	buf->ccontext.DataOffset = cpu_to_le16(0);
+	buf->ccontext.DataLength = cpu_to_le32(0);
+	buf->ccontext.NameOffset = cpu_to_le16(offsetof
+				(struct crt_query_id_ctxt, Name));
+	buf->ccontext.NameLength = cpu_to_le16(4);
+	/* SMB2_CREATE_QUERY_ON_DISK_ID is "QFid" */
+	buf->Name[0] = 'Q';
+	buf->Name[1] = 'F';
+	buf->Name[2] = 'i';
+	buf->Name[3] = 'd';
+	return buf;
+}
+
+/* See MS-SMB2 2.2.13.2.9 */
+static int
+add_query_id_context(struct kvec *iov, unsigned int *num_iovec)
+{
+	struct smb2_create_req *req = iov[0].iov_base;
+	unsigned int num = *num_iovec;
+
+	iov[num].iov_base = create_query_id_buf();
+	if (iov[num].iov_base == NULL)
+		return -ENOMEM;
+	iov[num].iov_len = sizeof(struct crt_query_id_ctxt);
+	if (!req->CreateContextsOffset)
+		req->CreateContextsOffset = cpu_to_le32(
+				sizeof(struct smb2_create_req) +
+				iov[num - 1].iov_len);
+	le32_add_cpu(&req->CreateContextsLength, sizeof(struct crt_query_id_ctxt));
+	*num_iovec = num + 1;
+	return 0;
+}
+
 static int
 alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
 			    const char *treename, const __le16 *path)
@@ -2446,6 +2488,12 @@  SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, __u8 *oplock,
 			return rc;
 	}
 
+	if (n_iov > 2) {
+		struct create_context *ccontext =
+			(struct create_context *)iov[n_iov-1].iov_base;
+		ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
+	}
+	add_query_id_context(iov, &n_iov);
 
 	rqst->rq_nvec = n_iov;
 	return 0;
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 053ec621e7b9..a397cea744cd 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -841,6 +841,12 @@  struct crt_twarp_ctxt {
 
 } __packed;
 
+/* See MS-SMB2 2.2.13.2.9 */
+struct crt_query_id_ctxt {
+	struct create_context ccontext;
+	__u8	Name[8];
+} __packed;
+
 #define COPY_CHUNK_RES_KEY_SIZE	24
 struct resume_key_req {
 	char ResumeKey[COPY_CHUNK_RES_KEY_SIZE];
-- 
2.20.1