nfs/nlm: procedures for PC clients

*  This change introduces four NLMv4 procedures:

   NM_LOCK, SHARE, UNSHARE and FREE_ALL.

   These are used by PC clients (windows/dos) to control access
   to files.

   1. NM_LOCK: this lock is not monitored by statd.

   2. SHARE: A share reservation is a lock on the whole file
      that is taken whenever a file is opened on windows clients.
      This has ACCESS (N, R, W, RW) and DENY MODE (N, R, W, RW).
        ACCESS:    mode of access requested by the client;
        DENY MODE: what the requesting client wants to
                   deny other clients.

   3. UNSHARE: remove a share reservation obtained by SHARE.
      Called while closing a file.

   4. FREE_ALL: remove all share reservations and locks,
      both monitored and unmonitored, of the calling client.

*  lock and nm_lock use a common function with only
   a flag conveying whether or not to monitor a lock.

*  NOTES:
   1. SHARE reservations are not STACK_WIND'd to subsequent xlators.
      These are maintained in-memory in the nfs xlator.

   2. Consequently, for SHARE reservations to work effectively,
      all PC clients  *must* mount from the same gNfs server.
      Not doing so will result in different servers maintaining
      separate SHARE reservations which will not be enforced
      for obvious reasons.

Change-Id: Id4f22670a94ed58691a6a7f4c80aa8c11421a277
BUG: 800287
Signed-off-by: Rajesh Amaravathi <rajesh@redhat.com>
Reviewed-on: http://review.gluster.com/3212
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishna Srinivas <krishna@gluster.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/xlators/nfs/server/src/nlm4.h b/xlators/nfs/server/src/nlm4.h
index db5874387f4..bcc7ae57343 100644
--- a/xlators/nfs/server/src/nlm4.h
+++ b/xlators/nfs/server/src/nlm4.h
@@ -60,11 +60,21 @@ typedef struct nlm_client {
         pid_t uniq;
         struct list_head nlm_clients;
         struct list_head fdes;
+        struct list_head shares;
         struct rpc_clnt *rpc_clnt;
         char *caller_name;
         int nsm_monitor;
 } nlm_client_t;
 
+typedef struct nlm_share {
+        struct list_head     client_list;
+        struct list_head     inode_list;
+        gf_lkowner_t         lkowner;
+        inode_t             *inode;
+        fsh_mode             mode;
+        fsh_access           access;
+} nlm_share_t;
+
 typedef struct nlm_fde {
         struct list_head fde_list;
         fd_t *fd;