Add SMB2.02 dialect support

This patch enables optional for original SMB2 (SMB2.02) dialect
by specifying vers=2.0 on mount.

Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

3 files changed, 23 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d1a93d32db81..ac66409fb9d3 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -178,6 +178,7 @@ struct smb_rqst {
 
 enum smb_version {
         Smb_1 = 1,
+        Smb_20,
         Smb_21,
         Smb_30,
 };
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 5ce5686353f1..d01c7328dbae 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -274,6 +274,7 @@ static const match_table_t cifs_cacheflavor_tokens = {
 
 static const match_table_t cifs_smb_version_tokens = {
         { Smb_1, SMB1_VERSION_STRING },
+        { Smb_20, SMB20_VERSION_STRING},
         { Smb_21, SMB21_VERSION_STRING },
         { Smb_30, SMB30_VERSION_STRING },
 };
@@ -1074,6 +1075,10 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol)
                 vol->vals = &smb1_values;
                 break;
 #ifdef CONFIG_CIFS_SMB2
+        case Smb_20:
+                vol->ops = &smb21_operations; /* currently identical with 2.1 */
+                vol->vals = &smb20_values;
+                break;
         case Smb_21:
                 vol->ops = &smb21_operations;
                 vol->vals = &smb21_values;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 137aaf8d6f38..ad4d96a4bff5 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -625,6 +625,23 @@ struct smb_version_operations smb21_operations = {
         .new_lease_key = smb2_new_lease_key,
 };
 
+struct smb_version_values smb20_values = {
+        .version_string = SMB20_VERSION_STRING,
+        .protocol_id = SMB20_PROT_ID,
+        .req_capabilities = 0, /* MBZ */
+        .large_lock_type = 0,
+        .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
+        .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
+        .unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
+        .header_size = sizeof(struct smb2_hdr),
+        .max_header_size = MAX_SMB2_HDR_SIZE,
+        .read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
+        .lock_cmd = SMB2_LOCK,
+        .cap_unix = 0,
+        .cap_nt_find = SMB2_NT_FIND,
+        .cap_large_files = SMB2_LARGE_FILES,
+};
+
 struct smb_version_values smb21_values = {
         .version_string = SMB21_VERSION_STRING,
         .protocol_id = SMB21_PROT_ID,