From 2402453b330e10d8efd767ffcf224744feb3cf94 Mon Sep 17 00:00:00 2001
From: Kern Sibbald <kern@sibbald.com>
Date: Sun, 7 Mar 2010 17:09:32 +0100
Subject: [PATCH] More devlock work

---
 bacula/src/lib/devlock.c | 45 ++++++++++++++++++++++++++++++++++++++--
 bacula/src/lib/devlock.h | 18 +++++++++++++---
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/bacula/src/lib/devlock.c b/bacula/src/lib/devlock.c
index 2d36c6b86f..c85721f79d 100644
--- a/bacula/src/lib/devlock.c
+++ b/bacula/src/lib/devlock.c
@@ -240,7 +240,7 @@ int devlock::readunlock()
  * Lock for write access, wait until locked (or error).
  *   Multiple nested write locking is permitted.
  */
-int devlock::writelock(int areason, bool acan_steal)
+int devlock::writelock(int areason, bool acan_take)
 {
    devlock *rwl = this;
    int stat;
@@ -275,7 +275,7 @@ int devlock::writelock(int areason, bool acan_steal)
       lmgr_post_lock();
    } 
    rwl->reason = areason;
-   rwl->can_steal = acan_steal;
+   rwl->can_take = acan_take;
    pthread_mutex_unlock(&rwl->mutex);
    return stat;
 }
@@ -349,6 +349,47 @@ int devlock::writeunlock()
    return (stat == 0 ? stat2 : stat);
 }
 
+int devlock::take_lock(take_lock_t *hold, int areason)
+{
+   int stat;
+
+   if (valid != DEVLOCK_VALID) {
+      return EINVAL;
+   }
+   if ((stat = pthread_mutex_lock(&mutex)) != 0) {
+      return stat;
+   }
+   hold->reason = reason;
+   hold->prev_reason = prev_reason;
+   hold->writer_id = writer_id;
+   reason = areason;
+   writer_id = pthread_self();
+   stat = pthread_mutex_unlock(&mutex);
+   return stat;
+}
+
+int devlock::return_lock(take_lock_t *hold)
+{
+   int stat, stat2;
+
+   if (valid != DEVLOCK_VALID) {
+      return EINVAL;
+   }
+   if ((stat = pthread_mutex_lock(&mutex)) != 0) {
+      return stat;
+   }
+   reason = hold->reason;
+   prev_reason = hold->prev_reason;
+   writer_id = hold->writer_id;
+   writer_id = pthread_self();
+   stat2 = pthread_mutex_unlock(&mutex);
+   if (w_active || w_wait) {
+      stat = pthread_cond_broadcast(&write);
+   }
+   return (stat == 0 ? stat2 : stat);
+
+}
+
 #ifdef TEST_RWLOCK
 
 #define THREADS     300
diff --git a/bacula/src/lib/devlock.h b/bacula/src/lib/devlock.h
index b8ad3513c2..bf2e4f6b14 100644
--- a/bacula/src/lib/devlock.h
+++ b/bacula/src/lib/devlock.h
@@ -39,6 +39,13 @@
 #ifndef __DEVLOCK_H
 #define __DEVLOCK_H 1
 
+struct take_lock_t {
+   pthread_t  writer_id;              /* id of writer */
+   int        reason;                 /* save reason */
+   int        prev_reason;            /* previous reason */
+};
+
+
 class devlock {
 private:
    pthread_mutex_t   mutex;
@@ -52,16 +59,21 @@ private:
    int               r_wait;          /* readers waiting */
    int               w_wait;          /* writers waiting */
    int               reason;          /* reason for lock */
-   bool              can_steal;       /* can the lock be stolen? */
+   int               prev_reason;     /* previous reason */
+   bool              can_take;        /* can the lock be taken? */
 
 
 public:
-   devlock(int reason, bool can_steal=false);
+   devlock(int reason, bool can_take=false);
    ~devlock();
    int init(int priority);
    int destroy();
+   int take_lock(take_lock_t *hold, int reason);
+   int return_lock(take_lock_t *hold);
+   void new_reason(int nreason) { prev_reason = reason; reason = nreason; };
+   void restore_reason() { reason = prev_reason; prev_reason = 0; };
 
-   int writelock(int reason, bool can_steal=false); 
+   int writelock(int reason, bool can_take=false); 
    int writetrylock();
    int writeunlock();
    void write_release();
-- 
2.39.5