lockd: Convert NLM service fl_owner to nlm_lockowner

Do as the NLM client: allocate and track a struct nlm_lockowner for use as
the fl_owner for locks created by the NLM sever.  This allows us to keep
the svid within this structure for matching locks, and will allow us to
track the pid of lockd in a future patch.  It should also allow easier
reference of the nlm_host in conflicting locks, and simplify lock hashing
and comparison.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
[bfields@redhat.com: fix type of some error returns]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

6 files changed, 121 insertions, 5 deletions

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index 1bddf70d9656..a00134fd8956 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -46,8 +46,13 @@ nlm4svc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
 
                 /* Set up the missing parts of the file_lock structure */
                 lock->fl.fl_file  = file->f_file;
-                lock->fl.fl_owner = (fl_owner_t) host;
                 lock->fl.fl_lmops = &nlmsvc_lock_operations;
+                nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+                if (!lock->fl.fl_owner) {
+                        /* lockowner allocation has failed */
+                        nlmsvc_release_host(host);
+                        return nlm_lck_denied_nolocks;
+                }
         }
 
         return 0;
@@ -94,6 +99,7 @@ __nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp)
         else
                 dprintk("lockd: TEST4        status %d\n", ntohl(resp->status));
 
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rc;
@@ -142,6 +148,7 @@ __nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
         else
                 dprintk("lockd: LOCK         status %d\n", ntohl(resp->status));
 
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rc;
@@ -178,6 +185,7 @@ __nlm4svc_proc_cancel(struct svc_rqst *rqstp, struct nlm_res *resp)
         resp->status = nlmsvc_cancel_blocked(SVC_NET(rqstp), file, &argp->lock);
 
         dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -217,6 +225,7 @@ __nlm4svc_proc_unlock(struct svc_rqst *rqstp, struct nlm_res *resp)
         resp->status = nlmsvc_unlock(SVC_NET(rqstp), file, &argp->lock);
 
         dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -365,6 +374,7 @@ nlm4svc_proc_share(struct svc_rqst *rqstp)
         resp->status = nlmsvc_share_file(host, file, argp);
 
         dprintk("lockd: SHARE         status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -399,6 +409,7 @@ nlm4svc_proc_unshare(struct svc_rqst *rqstp)
         resp->status = nlmsvc_unshare_file(host, file, argp);
 
         dprintk("lockd: UNSHARE       status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index ea719cdd6a36..34c6ee85274e 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -332,6 +332,93 @@ restart:
         mutex_unlock(&file->f_mutex);
 }
 
+static struct nlm_lockowner *
+nlmsvc_get_lockowner(struct nlm_lockowner *lockowner)
+{
+        refcount_inc(&lockowner->count);
+        return lockowner;
+}
+
+static void nlmsvc_put_lockowner(struct nlm_lockowner *lockowner)
+{
+        if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
+                return;
+        list_del(&lockowner->list);
+        spin_unlock(&lockowner->host->h_lock);
+        nlmsvc_release_host(lockowner->host);
+        kfree(lockowner);
+}
+
+static struct nlm_lockowner *__nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+        struct nlm_lockowner *lockowner;
+        list_for_each_entry(lockowner, &host->h_lockowners, list) {
+                if (lockowner->pid != pid)
+                        continue;
+                return nlmsvc_get_lockowner(lockowner);
+        }
+        return NULL;
+}
+
+static struct nlm_lockowner *nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
+{
+        struct nlm_lockowner *res, *new = NULL;
+
+        spin_lock(&host->h_lock);
+        res = __nlmsvc_find_lockowner(host, pid);
+
+        if (res == NULL) {
+                spin_unlock(&host->h_lock);
+                new = kmalloc(sizeof(*res), GFP_KERNEL);
+                spin_lock(&host->h_lock);
+                res = __nlmsvc_find_lockowner(host, pid);
+                if (res == NULL && new != NULL) {
+                        res = new;
+                        /* fs/locks.c will manage the refcount through lock_ops */
+                        refcount_set(&new->count, 1);
+                        new->pid = pid;
+                        new->host = nlm_get_host(host);
+                        list_add(&new->list, &host->h_lockowners);
+                        new = NULL;
+                }
+        }
+
+        spin_unlock(&host->h_lock);
+        kfree(new);
+        return res;
+}
+
+void
+nlmsvc_release_lockowner(struct nlm_lock *lock)
+{
+        if (lock->fl.fl_owner)
+                nlmsvc_put_lockowner(lock->fl.fl_owner);
+}
+
+static void nlmsvc_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+        struct nlm_lockowner *nlm_lo = (struct nlm_lockowner *)fl->fl_owner;
+        new->fl_owner = nlmsvc_get_lockowner(nlm_lo);
+}
+
+static void nlmsvc_locks_release_private(struct file_lock *fl)
+{
+        nlmsvc_put_lockowner((struct nlm_lockowner *)fl->fl_owner);
+}
+
+const struct file_lock_operations nlmsvc_lock_ops = {
+        .fl_copy_lock = nlmsvc_locks_copy_lock,
+        .fl_release_private = nlmsvc_locks_release_private,
+};
+
+void nlmsvc_locks_init_private(struct file_lock *fl, struct nlm_host *host,
+                                                pid_t pid)
+{
+        fl->fl_owner = nlmsvc_find_lockowner(host, pid);
+        if (fl->fl_owner != NULL)
+                fl->fl_ops = &nlmsvc_lock_ops;
+}
+
 /*
  * Initialize arguments for GRANTED call. The nlm_rqst structure
  * has been cleared already.
@@ -509,6 +596,7 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
 {
         int                     error;
         __be32                  ret;
+        struct nlm_lockowner    *test_owner;
 
         dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
                                 locks_inode(file->f_file)->i_sb->s_id,
@@ -522,6 +610,9 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
                 goto out;
         }
 
+        /* If there's a conflicting lock, remember to clean up the test lock */
+        test_owner = (struct nlm_lockowner *)lock->fl.fl_owner;
+
         error = vfs_test_lock(file->f_file, &lock->fl);
         if (error) {
                 /* We can't currently deal with deferred test requests */
@@ -548,6 +639,11 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
         conflock->fl.fl_start = lock->fl.fl_start;
         conflock->fl.fl_end = lock->fl.fl_end;
         locks_release_private(&lock->fl);
+
+        /* Clean up the test lock */
+        lock->fl.fl_owner = NULL;
+        nlmsvc_put_lockowner(test_owner);
+
         ret = nlm_lck_denied;
 out:
         return ret;
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index ea77c66d3cc3..36245ab43ae3 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -76,8 +76,13 @@ nlmsvc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
 
                 /* Set up the missing parts of the file_lock structure */
                 lock->fl.fl_file  = file->f_file;
-                lock->fl.fl_owner = (fl_owner_t) host;
                 lock->fl.fl_lmops = &nlmsvc_lock_operations;
+                nlmsvc_locks_init_private(&lock->fl, host, (pid_t)lock->svid);
+                if (!lock->fl.fl_owner) {
+                        /* lockowner allocation has failed */
+                        nlmsvc_release_host(host);
+                        return nlm_lck_denied_nolocks;
+                }
         }
 
         return 0;
@@ -125,6 +130,7 @@ __nlmsvc_proc_test(struct svc_rqst *rqstp, struct nlm_res *resp)
                 dprintk("lockd: TEST          status %d vers %d\n",
                         ntohl(resp->status), rqstp->rq_vers);
 
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rc;
@@ -173,6 +179,7 @@ __nlmsvc_proc_lock(struct svc_rqst *rqstp, struct nlm_res *resp)
         else
                 dprintk("lockd: LOCK         status %d\n", ntohl(resp->status));
 
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rc;
@@ -210,6 +217,7 @@ __nlmsvc_proc_cancel(struct svc_rqst *rqstp, struct nlm_res *resp)
         resp->status = cast_status(nlmsvc_cancel_blocked(net, file, &argp->lock));
 
         dprintk("lockd: CANCEL        status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -250,6 +258,7 @@ __nlmsvc_proc_unlock(struct svc_rqst *rqstp, struct nlm_res *resp)
         resp->status = cast_status(nlmsvc_unlock(net, file, &argp->lock));
 
         dprintk("lockd: UNLOCK        status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -408,6 +417,7 @@ nlmsvc_proc_share(struct svc_rqst *rqstp)
         resp->status = cast_status(nlmsvc_share_file(host, file, argp));
 
         dprintk("lockd: SHARE         status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
@@ -442,6 +452,7 @@ nlmsvc_proc_unshare(struct svc_rqst *rqstp)
         resp->status = cast_status(nlmsvc_unshare_file(host, file, argp));
 
         dprintk("lockd: UNSHARE       status %d\n", ntohl(resp->status));
+        nlmsvc_release_lockowner(&argp->lock);
         nlmsvc_release_host(host);
         nlm_release_file(file);
         return rpc_success;
diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index 0e610f422406..028fc152da22 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -180,7 +180,7 @@ again:
                 /* update current lock count */
                 file->f_locks++;
 
-                lockhost = (struct nlm_host *) fl->fl_owner;
+                lockhost = ((struct nlm_lockowner *)fl->fl_owner)->host;
                 if (match(lockhost, host)) {
                         struct file_lock lock = *fl;
 
diff --git a/fs/lockd/xdr.c b/fs/lockd/xdr.c
index 7147e4aebecc..ec717ae41ee3 100644
--- a/fs/lockd/xdr.c
+++ b/fs/lockd/xdr.c
@@ -126,7 +126,6 @@ nlm_decode_lock(__be32 *p, struct nlm_lock *lock)
         lock->svid  = ntohl(*p++);
 
         locks_init_lock(fl);
-        fl->fl_owner = current->files;
         fl->fl_pid   = (pid_t)lock->svid;
         fl->fl_flags = FL_POSIX;
         fl->fl_type  = F_RDLCK;         /* as good as anything else */
diff --git a/fs/lockd/xdr4.c b/fs/lockd/xdr4.c
index 7ed9edf9aed4..45741adfe041 100644
--- a/fs/lockd/xdr4.c
+++ b/fs/lockd/xdr4.c
@@ -118,7 +118,6 @@ nlm4_decode_lock(__be32 *p, struct nlm_lock *lock)
         lock->svid  = ntohl(*p++);
 
         locks_init_lock(fl);
-        fl->fl_owner = current->files;
         fl->fl_pid   = (pid_t)lock->svid;
         fl->fl_flags = FL_POSIX;
         fl->fl_type  = F_RDLCK;         /* as good as anything else */