lockd: add code to handle deferred lock requests

Rewrite nlmsvc_lock() to use the asynchronous interface.

As with testlock, we answer nlm requests in nlmsvc_lock by first looking up
the block and then using the results we find in the block if B_QUEUED is
set, and calling vfs_lock_file() otherwise.

If this a new lock request and we get -EINPROGRESS return on a non-blocking
request then we defer the request.

Also modify nlmsvc_unlock() to call the filesystem method if appropriate.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index 205d8befbf1b..bf27b6c6cb6b 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -145,6 +145,8 @@ nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_args *argp,
         /* Now try to lock the file */
         resp->status = nlmsvc_lock(rqstp, file, &argp->lock,
                                         argp->block, &argp->cookie);
+        if (resp->status == nlm_drop_reply)
+                return rpc_drop_reply;
 
         dprintk("lockd: LOCK          status %d\n", ntohl(resp->status));
         nlm_release_host(host);