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Code Releases Activity

Use condition instead of sleep

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Replace usleep with pthread condition to increase speed testing
(for simplicity just 1 condition for all locks).

Use thread mutex also for unlock resource (so it wakes up awaiting
threads)

Better check some error states and return error in fail case with
unlocked mutex.
This commit is contained in:
Zdenek Kabelac 2011-10-11 09:05:20 +00:00
parent df251f14dc
commit efe62a3411
2 changed files with 36 additions and 22 deletions
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1
WHATS_NEW
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@ -1,5 +1,6 @@
Version 2.02.89 -
==================================
Use pthread condition for SINGLENODE lock implementation.
Improve backtrace reporting for some dev_manager_ functions.
Change message severity to log_warn when symlink creation fails.
Add ability to convert mirror segtype to RAID1 segtype.

57
daemons/clvmd/clvmd-singlenode.c
View File

@ -147,6 +147,8 @@ int _lock_file(const char *file, uint32_t flags);
static int _lock_max = 1;
static pthread_mutex_t _lock_mutex = PTHREAD_MUTEX_INITIALIZER;
/* Using one common condition for all locks for simplicity */
static pthread_cond_t _lock_cond = PTHREAD_COND_INITIALIZER;
/* Real locking */
static int _lock_resource(const char *resource, int mode, int flags, int *lockid)
@ -155,11 +157,11 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
char **_resources_1;
int i, j;
DEBUGLOG("lock_resource '%s', flags=%d, mode=%d\n",
DEBUGLOG("Locking resource %s, flags=%d, mode=%d\n",
resource, flags, mode);
retry:
pthread_mutex_lock(&_lock_mutex);
retry:
/* look for an existing lock for this resource */
for (i = 1; i < _lock_max; ++i) {
@ -168,12 +170,12 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
if (!strcmp(_resources[i], resource)) {
if ((_locks[i] & LCK_TYPE_MASK) == LCK_WRITE ||
(_locks[i] & LCK_TYPE_MASK) == LCK_EXCL) {
DEBUGLOG("%s already write/exclusively locked...\n", resource);
DEBUGLOG("Resource %s already write/exclusively locked...\n", resource);
goto maybe_retry;
}
if ((mode & LCK_TYPE_MASK) == LCK_WRITE ||
(mode & LCK_TYPE_MASK) == LCK_EXCL) {
DEBUGLOG("%s already locked and WRITE/EXCL lock requested...\n",
DEBUGLOG("Resource %s already locked and WRITE/EXCL lock requested...\n",
resource);
goto maybe_retry;
}
@ -181,15 +183,14 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
}
if (i == _lock_max) { /* out of lock slots, extend */
_locks_1 = dm_realloc(_locks, 2 * _lock_max * sizeof(int));
if (!_locks_1)
return 1; /* fail */
if (!(_locks_1 = dm_realloc(_locks, 2 * _lock_max * sizeof(int))))
goto_bad;
_locks = _locks_1;
_resources_1 = dm_realloc(_resources, 2 * _lock_max * sizeof(char *));
if (!_resources_1) {
if (!(_resources_1 = dm_realloc(_resources, 2 * _lock_max * sizeof(char *))))
/* _locks may get realloc'd twice, but that should be safe */
return 1; /* fail */
}
goto_bad;
_resources = _resources_1;
/* clear the new resource entries */
for (j = _lock_max; j < 2 * _lock_max; ++j)
@ -198,40 +199,52 @@ static int _lock_resource(const char *resource, int mode, int flags, int *lockid
}
/* resource is not currently locked, grab it */
if (!(_resources[i] = dm_strdup(resource)))
goto_bad;
*lockid = i;
_locks[i] = mode;
_resources[i] = dm_strdup(resource);
DEBUGLOG("%s locked -> %d\n", resource, i);
DEBUGLOG("Locked resource %s, lockid=%d\n", resource, i);
pthread_mutex_unlock(&_lock_mutex);
return 0;
maybe_retry:
pthread_mutex_unlock(&_lock_mutex);
maybe_retry:
if (!(flags & LCK_NONBLOCK)) {
usleep(10000);
pthread_cond_wait(&_lock_cond, &_lock_mutex);
goto retry;
}
bad:
DEBUGLOG("Failed to lock resource %s\n", resource);
pthread_mutex_unlock(&_lock_mutex);
return 1; /* fail */
}
static int _unlock_resource(const char *resource, int lockid)
{
DEBUGLOG("unlock_resource: %s lockid: %x\n", resource, lockid);
if(!_resources[lockid]) {
DEBUGLOG("(%s) %d not locked\n", resource, lockid);
DEBUGLOG("Unlocking resource %s, lockid=%d\n", resource, lockid);
pthread_mutex_lock(&_lock_mutex);
if (!_resources[lockid]) {
pthread_mutex_unlock(&_lock_mutex);
DEBUGLOG("Resource %s, lockid=%d is not locked\n", resource, lockid);
return 1;
}
if(strcmp(_resources[lockid], resource)) {
DEBUGLOG("%d has wrong resource (requested %s, got %s)\n",
if (strcmp(_resources[lockid], resource)) {
pthread_mutex_unlock(&_lock_mutex);
DEBUGLOG("Resource %d has wrong resource (requested %s, got %s)\n",
lockid, resource, _resources[lockid]);
return 1;
}
dm_free(_resources[lockid]);
_resources[lockid] = 0;
pthread_cond_broadcast(&_lock_cond); /* wakeup waiters */
pthread_mutex_unlock(&_lock_mutex);
return 0;
}