cifs: maintain a state machine for tcp/smb/tcon sessions
If functions like cifs_negotiate_protocol, cifs_setup_session,
cifs_tree_connect are called in parallel on different channels,
each of these will be execute the requests. This maybe unnecessary
in some cases, and only the first caller may need to do the work.
This is achieved by having more states for the tcp/smb/tcon session
status fields. And tracking the state of reconnection based on the
state machine.
For example:
for tcp connections:
CifsNew/CifsNeedReconnect ->
CifsNeedNegotiate ->
CifsInNegotiate ->
CifsNeedSessSetup ->
CifsInSessSetup ->
CifsGood
for smb sessions:
CifsNew/CifsNeedReconnect ->
CifsGood
for tcon:
CifsNew/CifsNeedReconnect ->
CifsInFilesInvalidate ->
CifsNeedTcon ->
CifsInTcon ->
CifsGood
If any channel reconnect sees that it's in the middle of
transition to CifsGood, then they can skip the function.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 4ba35fa..f88d2b1 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -113,7 +113,13 @@ enum statusEnum {
CifsGood,
CifsExiting,
CifsNeedReconnect,
- CifsNeedNegotiate
+ CifsNeedNegotiate,
+ CifsInNegotiate,
+ CifsNeedSessSetup,
+ CifsInSessSetup,
+ CifsNeedTcon,
+ CifsInTcon,
+ CifsInFilesInvalidate
};
enum securityEnum {