CIFS: Request durable open for SMB2 opens

by passing durable context together with a handle caching lease or
batch oplock.

Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steven French <steven@steven-GA-970A-DS3.(none)>

3 files changed, 68 insertions, 2 deletions

diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c
index 46a4299b7ae8..150a9b1bc7fa 100644
--- a/fs/cifs/smb2file.c
+++ b/fs/cifs/smb2file.c
@@ -81,7 +81,7 @@ smb2_open_file(const unsigned int xid, struct cifs_tcon *tcon, const char *path,
         }
 
         desired_access |= FILE_READ_ATTRIBUTES;
-        *smb2_oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
+        *smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;
 
         if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
                 memcpy(smb2_oplock + 1, fid->lease_key, SMB2_LEASE_KEY_SIZE);
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index e65ccdb528cf..140a613073fb 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -847,6 +847,28 @@ create_lease_buf(u8 *lease_key, u8 oplock)
         return buf;
 }
 
+static struct create_durable *
+create_durable_buf(void)
+{
+        struct create_durable *buf;
+
+        buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
+        if (!buf)
+                return NULL;
+
+        buf->ccontext.DataOffset = cpu_to_le16(offsetof
+                                        (struct create_durable, Reserved));
+        buf->ccontext.DataLength = cpu_to_le32(16);
+        buf->ccontext.NameOffset = cpu_to_le16(offsetof
+                                (struct create_durable, Name));
+        buf->ccontext.NameLength = cpu_to_le16(4);
+        buf->Name[0] = 'D';
+        buf->Name[1] = 'H';
+        buf->Name[2] = 'n';
+        buf->Name[3] = 'Q';
+        return buf;
+}
+
 static __u8
 parse_lease_state(struct smb2_create_rsp *rsp)
 {
@@ -901,6 +923,28 @@ add_lease_context(struct kvec *iov, unsigned int *num_iovec, __u8 *oplock)
         return 0;
 }
 
+static int
+add_durable_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_durable_buf();
+        if (iov[num].iov_base == NULL)
+                return -ENOMEM;
+        iov[num].iov_len = sizeof(struct create_durable);
+        if (!req->CreateContextsOffset)
+                req->CreateContextsOffset =
+                        cpu_to_le32(sizeof(struct smb2_create_req) - 4 +
+                                                                iov[1].iov_len);
+        req->CreateContextsLength =
+                        cpu_to_le32(le32_to_cpu(req->CreateContextsLength) +
+                                                sizeof(struct create_durable));
+        inc_rfc1001_len(&req->hdr, sizeof(struct create_durable));
+        *num_iovec = num + 1;
+        return 0;
+}
+
 int
 SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
           u64 *persistent_fid, u64 *volatile_fid, __u32 desired_access,
@@ -911,7 +955,7 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
         struct smb2_create_rsp *rsp;
         struct TCP_Server_Info *server;
         struct cifs_ses *ses = tcon->ses;
-        struct kvec iov[3];
+        struct kvec iov[4];
         int resp_buftype;
         int uni_path_len;
         __le16 *copy_path = NULL;
@@ -987,6 +1031,22 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
                 }
         }
 
+        if (*oplock == SMB2_OPLOCK_LEVEL_BATCH) {
+                /* need to set Next field of lease context if we request it */
+                if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING) {
+                        struct create_context *ccontext =
+                            (struct create_context *)iov[num_iovecs-1].iov_base;
+                        ccontext->Next = sizeof(struct create_lease);
+                }
+                rc = add_durable_context(iov, &num_iovecs);
+                if (rc) {
+                        cifs_small_buf_release(req);
+                        kfree(copy_path);
+                        kfree(iov[num_iovecs-1].iov_base);
+                        return rc;
+                }
+        }
+
         rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
         rsp = (struct smb2_create_rsp *)iov[0].iov_base;
 
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 8b1025f6f0da..3e30f0ad5749 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -485,6 +485,12 @@ struct create_lease {
         struct lease_context lcontext;
 } __packed;
 
+struct create_durable {
+        struct create_context ccontext;
+        __u8   Name[8];
+        __u8   Reserved[16];
+} __packed;
+
 /* this goes in the ioctl buffer when doing a copychunk request */
 struct copychunk_ioctl {
         char SourceKey[24];