CIFS: Separate RFC1001 length processing for SMB2 read

BugLink: http://bugs.launchpad.net/bugs/1670508
Allocate and initialize SMB2 read request without RFC1001 length
field to directly call cifs_send_recv() rather than SendReceive2()
in a read codepath.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
(cherry picked from commit b8f57ee8aad414a3122bff72d7968a94baacb9b6)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 7b20993a5acc409dfffbe77608d4c2ff71796aec..711718cd73dd3daf8b3fd759e9b9b8c60c82577f 100644 (file)
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -79,6 +79,9 @@ extern int cifs_call_async(struct TCP_Server_Info *server,
                        struct smb_rqst *rqst,
                        mid_receive_t *receive, mid_callback_t *callback,
                        void *cbdata, const int flags);
+extern int cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
+                         struct smb_rqst *rqst, int *resp_buf_type,
+                         const int flags, struct kvec *resp_iov);
 extern int SendReceive(const unsigned int /* xid */ , struct cifs_ses *,
                        struct smb_hdr * /* input */ ,
                        struct smb_hdr * /* out */ ,

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index f6ba2c03f7cce1b6a7ec0f855d3170dfd02a9d5b..d1a90371b649ccf02f95f958fde55ea26372e91e 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -293,10 +293,46 @@ fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
        *total_len = parmsize + sizeof(struct smb2_sync_hdr);
 }
 
+/* init request without RFC1001 length at the beginning */
+static int
+smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
+                   void **request_buf, unsigned int *total_len)
+{
+       int rc;
+       struct smb2_sync_hdr *shdr;
+
+       rc = smb2_reconnect(smb2_command, tcon);
+       if (rc)
+               return rc;
+
+       /* BB eventually switch this to SMB2 specific small buf size */
+       *request_buf = cifs_small_buf_get();
+       if (*request_buf == NULL) {
+               /* BB should we add a retry in here if not a writepage? */
+               return -ENOMEM;
+       }
+
+       shdr = (struct smb2_sync_hdr *)(*request_buf);
+
+       fill_small_buf(smb2_command, tcon, shdr, total_len);
+
+       if (tcon != NULL) {
+#ifdef CONFIG_CIFS_STATS2
+               uint16_t com_code = le16_to_cpu(smb2_command);
+
+               cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_sent[com_code]);
+#endif
+               cifs_stats_inc(&tcon->num_smbs_sent);
+       }
+
+       return rc;
+}
+
 /*
  * Allocate and return pointer to an SMB request hdr, and set basic
  * SMB information in the SMB header. If the return code is zero, this
- * function must have filled in request_buf pointer.
+ * function must have filled in request_buf pointer. The returned buffer
+ * has RFC1001 length at the beginning.
  */
 static int
 small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
@@ -2140,16 +2176,17 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
                  int request_type)
 {
        int rc = -EACCES;
-       struct smb2_read_req *req = NULL;
+       struct smb2_read_plain_req *req = NULL;
        struct smb2_sync_hdr *shdr;
 
-       rc = small_smb2_init(SMB2_READ, io_parms->tcon, (void **) &req);
+       rc = smb2_plain_req_init(SMB2_READ, io_parms->tcon, (void **) &req,
+                                total_len);
        if (rc)
                return rc;
        if (io_parms->tcon->ses->server == NULL)
                return -ECONNABORTED;
 
-       shdr = get_sync_hdr(req);
+       shdr = &req->sync_hdr;
        shdr->ProcessId = cpu_to_le32(io_parms->pid);
 
        req->PersistentFileId = io_parms->persistent_fid;
@@ -2163,9 +2200,9 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 
        if (request_type & CHAINED_REQUEST) {
                if (!(request_type & END_OF_CHAIN)) {
-                       /* 4 for rfc1002 length field */
-                       shdr->NextCommand =
-                               cpu_to_le32(get_rfc1002_length(req) + 4);
+                       /* next 8-byte aligned request */
+                       *total_len = DIV_ROUND_UP(*total_len, 8) * 8;
+                       shdr->NextCommand = cpu_to_le32(*total_len);
                } else /* END_OF_CHAIN */
                        shdr->NextCommand = 0;
                if (request_type & RELATED_REQUEST) {
@@ -2186,8 +2223,6 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
                req->RemainingBytes = 0;
 
        *buf = req;
-       /* 4 for rfc1002 length field */
-       *total_len = get_rfc1002_length(req) + 4;
        return rc;
 }
 
@@ -2264,6 +2299,7 @@ smb2_async_readv(struct cifs_readdata *rdata)
                                 .rq_nvec = 2 };
        struct TCP_Server_Info *server;
        unsigned int total_len;
+       __be32 req_len;
 
        cifs_dbg(FYI, "%s: offset=%llu bytes=%u\n",
                 __func__, rdata->offset, rdata->bytes);
@@ -2290,12 +2326,14 @@ smb2_async_readv(struct cifs_readdata *rdata)
                return rc;
        }
 
-       shdr = get_sync_hdr(buf);
-       /* 4 for rfc1002 length field */
-       rdata->iov[0].iov_len = 4;
-       rdata->iov[0].iov_base = buf;
-       rdata->iov[1].iov_len = total_len - 4;
-       rdata->iov[1].iov_base = buf + 4;
+       req_len = cpu_to_be32(total_len);
+
+       rdata->iov[0].iov_base = &req_len;
+       rdata->iov[0].iov_len = sizeof(__be32);
+       rdata->iov[1].iov_base = buf;
+       rdata->iov[1].iov_len = total_len;
+
+       shdr = (struct smb2_sync_hdr *)buf;
 
        if (rdata->credits) {
                shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
@@ -2327,24 +2365,31 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
          unsigned int *nbytes, char **buf, int *buf_type)
 {
        int resp_buftype, rc = -EACCES;
+       struct smb2_read_plain_req *req = NULL;
        struct smb2_read_rsp *rsp = NULL;
        struct smb2_sync_hdr *shdr;
-       struct kvec iov[1];
+       struct kvec iov[2];
        struct kvec rsp_iov;
        unsigned int total_len;
-       char *req;
+       __be32 req_len;
+       struct smb_rqst rqst = { .rq_iov = iov,
+                                .rq_nvec = 2 };
 
        *nbytes = 0;
        rc = smb2_new_read_req((void **)&req, &total_len, io_parms, 0, 0);
        if (rc)
                return rc;
 
-       iov[0].iov_base = buf;
-       iov[0].iov_len = total_len;
+       req_len = cpu_to_be32(total_len);
 
-       rc = SendReceive2(xid, io_parms->tcon->ses, iov, 1,
-                         &resp_buftype, CIFS_LOG_ERROR, &rsp_iov);
-       cifs_small_buf_release(iov[0].iov_base);
+       iov[0].iov_base = &req_len;
+       iov[0].iov_len = sizeof(__be32);
+       iov[1].iov_base = req;
+       iov[1].iov_len = total_len;
+
+       rc = cifs_send_recv(xid, io_parms->tcon->ses, &rqst, &resp_buftype,
+                           CIFS_LOG_ERROR, &rsp_iov);
+       cifs_small_buf_release(req);
 
        rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;
        shdr = get_sync_hdr(rsp);

diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 052342da484484dc4b87ba513340ef23bd02eb51..35ff9fae1c27763e7ee089ee012c5474f38d4f2d 100644 (file)
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -823,8 +823,9 @@ struct smb2_flush_rsp {
 #define SMB2_CHANNEL_RDMA_V1           0x00000001 /* SMB3 or later */
 #define SMB2_CHANNEL_RDMA_V1_INVALIDATE 0x00000001 /* SMB3.02 or later */
 
-struct smb2_read_req {
-       struct smb2_hdr hdr;
+/* SMB2 read request without RFC1001 length at the beginning */
+struct smb2_read_plain_req {
+       struct smb2_sync_hdr sync_hdr;
        __le16 StructureSize; /* Must be 49 */
        __u8   Padding; /* offset from start of SMB2 header to place read */
        __u8   Flags; /* MBZ unless SMB3.02 or later */

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index dacfdf080330461b8a14b1898642e7c4cc08e349..729e5b7b80442467e6c5ab8bb2ca4b54064b2542 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -666,7 +666,7 @@ cifs_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
        return mid;
 }
 
-static int
+int
 cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
               struct smb_rqst *rqst, int *resp_buf_type, const int flags,
               struct kvec *resp_iov)