NFSv4: Teach NFSv4 to cache locks when we hold a delegation

 Now that we have a method of dealing with delegation recalls, actually
 enable the caching of posix and BSD locks.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e6a9322..21482b2 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2918,6 +2918,10 @@ static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *
        struct nfs4_lock_state *lsp;
        int status;
 
+       /* Is this a delegated lock? */
+       if (test_bit(NFS_DELEGATED_STATE, &state->flags))
+               return do_vfs_lock(request->fl_file, request);
+
        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                return status;
@@ -3032,6 +3036,9 @@ static int nfs4_lock_reclaim(struct nfs4_state *state, struct file_lock *request
        struct nfs4_exception exception = { };
        int err;
 
+       /* Cache the lock if possible... */
+       if (test_bit(NFS_DELEGATED_STATE, &state->flags))
+               return 0;
        do {
                err = _nfs4_do_setlk(state, F_SETLK, request, 1);
                if (err != -NFS4ERR_DELAY)
@@ -3047,6 +3054,9 @@ static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request
        struct nfs4_exception exception = { };
        int err;
 
+       err = nfs4_set_lock_state(state, request);
+       if (err != 0)
+               return err;
        do {
                err = _nfs4_do_setlk(state, F_SETLK, request, 0);
                if (err != -NFS4ERR_DELAY)
@@ -3062,15 +3072,25 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
        int status;
 
        down_read(&clp->cl_sem);
-       status = nfs4_set_lock_state(state, request);
-       if (status == 0)
-               status = _nfs4_do_setlk(state, cmd, request, 0);
-       if (status == 0) {
-               /* Note: we always want to sleep here! */
-               request->fl_flags |= FL_SLEEP;
-               if (do_vfs_lock(request->fl_file, request) < 0)
-                       printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
+       /* Is this a delegated open? */
+       if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
+               /* Yes: cache locks! */
+               status = do_vfs_lock(request->fl_file, request);
+               /* ...but avoid races with delegation recall... */
+               if (status < 0 || test_bit(NFS_DELEGATED_STATE, &state->flags))
+                       goto out;
        }
+       status = nfs4_set_lock_state(state, request);
+       if (status != 0)
+               goto out;
+       status = _nfs4_do_setlk(state, cmd, request, 0);
+       if (status != 0)
+               goto out;
+       /* Note: we always want to sleep here! */
+       request->fl_flags |= FL_SLEEP;
+       if (do_vfs_lock(request->fl_file, request) < 0)
+               printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__);
+out:
        up_read(&clp->cl_sem);
        return status;
 }