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>

1 files changed, 28 insertions, 8 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e6a9322a321f..21482b2518f6 100644
--- 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;
 }