[PATCH] Improve performance of POSIX open

* [PATCH] Improve performance of POSIX open - request query disk id open context
@ 2019-07-06  6:13 Steve French
  2019-07-06 16:34 ` Pavel Shilovsky
  0 siblings, 1 reply; 3+ messages in thread
From: Steve French @ 2019-07-06  6:13 UTC (permalink / raw)
  To: CIFS; +Cc: samba-technical

[-- Attachment #1: Type: text/plain, Size: 691 bytes --]

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

[-- Attachment #2: 0001-SMB3-query-inode-number-on-open-via-create-context.patch --]
[-- Type: text/x-patch, Size: 3469 bytes --]

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


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