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-rw-r--r--libglusterfs/src/syncop.c174
-rw-r--r--libglusterfs/src/syncop.h26
2 files changed, 146 insertions, 54 deletions
diff --git a/libglusterfs/src/syncop.c b/libglusterfs/src/syncop.c
index 20d4d00561c..cb08b03d44b 100644
--- a/libglusterfs/src/syncop.c
+++ b/libglusterfs/src/syncop.c
@@ -827,16 +827,20 @@ syncenv_new (size_t stacksize, int procmin, int procmax)
int
-synclock_init (synclock_t *lock)
+synclock_init (synclock_t *lock, lock_attr_t attr)
{
- if (!lock)
- return -1;
+ if (!lock)
+ return -1;
- pthread_cond_init (&lock->cond, 0);
- lock->lock = 0;
- INIT_LIST_HEAD (&lock->waitq);
+ pthread_cond_init (&lock->cond, 0);
+ lock->type = LOCK_NULL;
+ lock->owner = NULL;
+ lock->owner_tid = 0;
+ lock->lock = 0;
+ lock->attr = attr;
+ INIT_LIST_HEAD (&lock->waitq);
- return pthread_mutex_init (&lock->guard, 0);
+ return pthread_mutex_init (&lock->guard, 0);
}
@@ -854,32 +858,70 @@ synclock_destroy (synclock_t *lock)
static int
__synclock_lock (struct synclock *lock)
{
- struct synctask *task = NULL;
+ struct synctask *task = NULL;
- if (!lock)
- return -1;
+ if (!lock)
+ return -1;
- task = synctask_get ();
+ task = synctask_get ();
- while (lock->lock) {
- if (task) {
- /* called within a synctask */
- list_add_tail (&task->waitq, &lock->waitq);
+ if (lock->lock && (lock->attr == SYNC_LOCK_RECURSIVE)) {
+ /*Recursive lock (if same owner requested for lock again then
+ *increment lock count and return success).
+ *Note:same number of unlocks required.
+ */
+ switch (lock->type) {
+ case LOCK_TASK:
+ if (task == lock->owner) {
+ lock->lock++;
+ gf_log ("", GF_LOG_TRACE, "Recursive lock called by "
+ "sync task.owner= %p,lock=%d", lock->owner, lock->lock);
+ return 0;
+ }
+ break;
+ case LOCK_THREAD:
+ if (pthread_self () == lock->owner_tid) {
+ lock->lock++;
+ gf_log ("", GF_LOG_TRACE, "Recursive lock called by "
+ "thread ,owner=%u lock=%d", (unsigned int) lock->owner_tid,
+ lock->lock);
+ return 0;
+ }
+ break;
+ default:
+ gf_log ("", GF_LOG_CRITICAL, "unknown lock type");
+ break;
+ }
+ }
+
+
+ while (lock->lock) {
+ if (task) {
+ /* called within a synctask */
+ list_add_tail (&task->waitq, &lock->waitq);
pthread_mutex_unlock (&lock->guard);
synctask_yield (task);
/* task is removed from waitq in unlock,
* under lock->guard.*/
pthread_mutex_lock (&lock->guard);
- } else {
- /* called by a non-synctask */
- pthread_cond_wait (&lock->cond, &lock->guard);
- }
- }
+ } else {
+ /* called by a non-synctask */
+ pthread_cond_wait (&lock->cond, &lock->guard);
+ }
+ }
- lock->lock = _gf_true;
- lock->owner = task;
+ if (task) {
+ lock->type = LOCK_TASK;
+ lock->owner = task; /* for synctask*/
- return 0;
+ } else {
+ lock->type = LOCK_THREAD;
+ lock->owner_tid = pthread_self (); /* for non-synctask */
+
+ }
+ lock->lock = 1;
+
+ return 0;
}
@@ -925,37 +967,73 @@ unlock:
static int
__synclock_unlock (synclock_t *lock)
{
- struct synctask *task = NULL;
- struct synctask *curr = NULL;
+ struct synctask *task = NULL;
+ struct synctask *curr = NULL;
- if (!lock)
- return -1;
+ if (!lock)
+ return -1;
+
+ if (lock->lock == 0) {
+ gf_log ("", GF_LOG_CRITICAL, "Unlock called before lock ");
+ return -1;
+ }
+ curr = synctask_get ();
+ /*unlock should be called by lock owner
+ *i.e this will not allow the lock in nonsync task and unlock
+ * in sync task and vice-versa
+ */
+ switch (lock->type) {
+ case LOCK_TASK:
+ if (curr == lock->owner) {
+ lock->lock--;
+ gf_log ("", GF_LOG_TRACE, "Unlock success %p, remaining"
+ " locks=%d", lock->owner, lock->lock);
+ } else {
+ gf_log ("", GF_LOG_WARNING, "Unlock called by %p, but"
+ " lock held by %p", curr, lock->owner);
+ }
- curr = synctask_get ();
+ break;
+ case LOCK_THREAD:
+ if (pthread_self () == lock->owner_tid) {
+ lock->lock--;
+ gf_log ("", GF_LOG_TRACE, "Unlock success %u, remaining"
+ " locks=%d", (unsigned int)lock->owner_tid, lock->lock);
+ } else {
+ gf_log ("", GF_LOG_WARNING, "Unlock called by %u, but"
+ " lock held by %u", (unsigned int) pthread_self(),
+ (unsigned int) lock->owner_tid);
+ }
- if (lock->owner != curr) {
- /* warn ? */
- }
+ break;
+ default:
+ break;
+ }
- lock->lock = _gf_false;
-
- /* There could be both synctasks and non synctasks
- waiting (or none, or either). As a mid-approach
- between maintaining too many waiting counters
- at one extreme and a thundering herd on unlock
- at the other, call a cond_signal (which wakes
- one waiter) and first synctask waiter. So at
- most we have two threads waking up to grab the
- just released lock.
- */
- pthread_cond_signal (&lock->cond);
- if (!list_empty (&lock->waitq)) {
- task = list_entry (lock->waitq.next, struct synctask, waitq);
+ if (lock->lock > 0) {
+ return 0;
+ }
+ lock->type = LOCK_NULL;
+ lock->owner = NULL;
+ lock->owner_tid = 0;
+ lock->lock = 0;
+ /* There could be both synctasks and non synctasks
+ waiting (or none, or either). As a mid-approach
+ between maintaining too many waiting counters
+ at one extreme and a thundering herd on unlock
+ at the other, call a cond_signal (which wakes
+ one waiter) and first synctask waiter. So at
+ most we have two threads waking up to grab the
+ just released lock.
+ */
+ pthread_cond_signal (&lock->cond);
+ if (!list_empty (&lock->waitq)) {
+ task = list_entry (lock->waitq.next, struct synctask, waitq);
list_del_init (&task->waitq);
- synctask_wake (task);
- }
+ synctask_wake (task);
+ }
- return 0;
+ return 0;
}
diff --git a/libglusterfs/src/syncop.h b/libglusterfs/src/syncop.h
index 3a7798fa17e..f41706a9d37 100644
--- a/libglusterfs/src/syncop.h
+++ b/libglusterfs/src/syncop.h
@@ -114,12 +114,26 @@ struct syncenv {
};
+typedef enum {
+ LOCK_NULL = 0,
+ LOCK_TASK,
+ LOCK_THREAD
+} lock_type_t;
+
+typedef enum {
+ SYNC_LOCK_DEFAULT = 0,
+ SYNC_LOCK_RECURSIVE, /*it allows recursive locking*/
+} lock_attr_t;
+
struct synclock {
- pthread_mutex_t guard; /* guard the remaining members, pair @cond */
- pthread_cond_t cond; /* waiting non-synctasks */
- struct list_head waitq; /* waiting synctasks */
- gf_boolean_t lock; /* _gf_true or _gf_false, lock status */
- struct synctask *owner; /* NULL if current owner is not a synctask */
+ pthread_mutex_t guard; /* guard the remaining members, pair @cond */
+ pthread_cond_t cond; /* waiting non-synctasks */
+ struct list_head waitq; /* waiting synctasks */
+ volatile int lock; /* true(non zero) or false(zero), lock status */
+ lock_attr_t attr;
+ struct synctask *owner; /* NULL if current owner is not a synctask */
+ pthread_t owner_tid;
+ lock_type_t type;
};
typedef struct synclock synclock_t;
@@ -336,7 +350,7 @@ syncop_create_frame (xlator_t *this)
return frame;
}
-int synclock_init (synclock_t *lock);
+int synclock_init (synclock_t *lock, lock_attr_t attr);
int synclock_destroy (synclock_t *lock);
int synclock_lock (synclock_t *lock);
int synclock_trylock (synclock_t *lock);