Merge tag 'dlm-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

Pull dlm update from David Teigland:
 "This set includes one feature, which allows locks that have been
  orphaned to be reacquired"

* tag 'dlm-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: adopt orphan locks

4 files changed, 89 insertions, 5 deletions

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 83f3d5520307..35502d4046f5 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -5886,6 +5886,78 @@ int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
         return error;
 }
 
+/*
+ * The caller asks for an orphan lock on a given resource with a given mode.
+ * If a matching lock exists, it's moved to the owner's list of locks and
+ * the lkid is returned.
+ */
+
+int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
+                     int mode, uint32_t flags, void *name, unsigned int namelen,
+                     unsigned long timeout_cs, uint32_t *lkid)
+{
+        struct dlm_lkb *lkb;
+        struct dlm_user_args *ua;
+        int found_other_mode = 0;
+        int found = 0;
+        int rv = 0;
+
+        mutex_lock(&ls->ls_orphans_mutex);
+        list_for_each_entry(lkb, &ls->ls_orphans, lkb_ownqueue) {
+                if (lkb->lkb_resource->res_length != namelen)
+                        continue;
+                if (memcmp(lkb->lkb_resource->res_name, name, namelen))
+                        continue;
+                if (lkb->lkb_grmode != mode) {
+                        found_other_mode = 1;
+                        continue;
+                }
+
+                found = 1;
+                list_del_init(&lkb->lkb_ownqueue);
+                lkb->lkb_flags &= ~DLM_IFL_ORPHAN;
+                *lkid = lkb->lkb_id;
+                break;
+        }
+        mutex_unlock(&ls->ls_orphans_mutex);
+
+        if (!found && found_other_mode) {
+                rv = -EAGAIN;
+                goto out;
+        }
+
+        if (!found) {
+                rv = -ENOENT;
+                goto out;
+        }
+
+        lkb->lkb_exflags = flags;
+        lkb->lkb_ownpid = (int) current->pid;
+
+        ua = lkb->lkb_ua;
+
+        ua->proc = ua_tmp->proc;
+        ua->xid = ua_tmp->xid;
+        ua->castparam = ua_tmp->castparam;
+        ua->castaddr = ua_tmp->castaddr;
+        ua->bastparam = ua_tmp->bastparam;
+        ua->bastaddr = ua_tmp->bastaddr;
+        ua->user_lksb = ua_tmp->user_lksb;
+
+        /*
+         * The lkb reference from the ls_orphans list was not
+         * removed above, and is now considered the reference
+         * for the proc locks list.
+         */
+
+        spin_lock(&ua->proc->locks_spin);
+        list_add_tail(&lkb->lkb_ownqueue, &ua->proc->locks);
+        spin_unlock(&ua->proc->locks_spin);
+ out:
+        kfree(ua_tmp);
+        return rv;
+}
+
 int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
                     uint32_t flags, uint32_t lkid, char *lvb_in)
 {
@@ -6029,7 +6101,7 @@ static int orphan_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb)
         struct dlm_args args;
         int error;
 
-        hold_lkb(lkb);
+        hold_lkb(lkb); /* reference for the ls_orphans list */
         mutex_lock(&ls->ls_orphans_mutex);
         list_add_tail(&lkb->lkb_ownqueue, &ls->ls_orphans);
         mutex_unlock(&ls->ls_orphans_mutex);
@@ -6217,7 +6289,7 @@ int dlm_user_purge(struct dlm_ls *ls, struct dlm_user_proc *proc,
 {
         int error = 0;
 
-        if (nodeid != dlm_our_nodeid()) {
+        if (nodeid && (nodeid != dlm_our_nodeid())) {
                 error = send_purge(ls, nodeid, pid);
         } else {
                 dlm_lock_recovery(ls);
diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h
index 5e0c72e36a9b..ed8ebd3a8593 100644
--- a/fs/dlm/lock.h
+++ b/fs/dlm/lock.h
@@ -49,6 +49,9 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua, int mode,
 int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
         int mode, uint32_t flags, uint32_t lkid, char *lvb_in,
         unsigned long timeout_cs);
+int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
+        int mode, uint32_t flags, void *name, unsigned int namelen,
+        unsigned long timeout_cs, uint32_t *lkid);
 int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
         uint32_t flags, uint32_t lkid, char *lvb_in);
 int dlm_user_cancel(struct dlm_ls *ls,  struct dlm_user_args *ua_tmp,
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 142e21655eed..fb85f32e9eca 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -238,6 +238,7 @@ static int device_user_lock(struct dlm_user_proc *proc,
 {
         struct dlm_ls *ls;
         struct dlm_user_args *ua;
+        uint32_t lkid;
         int error = -ENOMEM;
 
         ls = dlm_find_lockspace_local(proc->lockspace);
@@ -260,12 +261,20 @@ static int device_user_lock(struct dlm_user_proc *proc,
         ua->bastaddr = params->bastaddr;
         ua->xid = params->xid;
 
-        if (params->flags & DLM_LKF_CONVERT)
+        if (params->flags & DLM_LKF_CONVERT) {
                 error = dlm_user_convert(ls, ua,
                                          params->mode, params->flags,
                                          params->lkid, params->lvb,
                                          (unsigned long) params->timeout);
-        else {
+        } else if (params->flags & DLM_LKF_ORPHAN) {
+                error = dlm_user_adopt_orphan(ls, ua,
+                                         params->mode, params->flags,
+                                         params->name, params->namelen,
+                                         (unsigned long) params->timeout,
+                                         &lkid);
+                if (!error)
+                        error = lkid;
+        } else {
                 error = dlm_user_request(ls, ua,
                                          params->mode, params->flags,
                                          params->name, params->namelen,
diff --git a/include/uapi/linux/dlmconstants.h b/include/uapi/linux/dlmconstants.h
index 47bf08dc7566..2857bdc5b27b 100644
--- a/include/uapi/linux/dlmconstants.h
+++ b/include/uapi/linux/dlmconstants.h
@@ -114,7 +114,7 @@
  *
  * DLM_LKF_ORPHAN
  *
- * not yet implemented
+ * Acquire an orphan lock.
  *
  * DLM_LKF_ALTPR
  *