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make dirty_page_table_flush be reentrant; fix possible dereference of null pointer

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This commit is contained in:
Sears Russell 2010-10-19 22:55:03 +00:00
parent 6f0c50d861
commit d26da056b7
1 changed files with 15 additions and 21 deletions
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26
src/stasis/dirtyPageTable.c
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@ -41,7 +41,6 @@ struct stasis_dirty_page_table_t {
int flushing; int flushing;
pthread_cond_t writebackCond; pthread_cond_t writebackCond;
lsn_t targetLsn;
}; };
void stasis_dirty_page_table_set_dirty(stasis_dirty_page_table_t * dirtyPages, Page * p) { void stasis_dirty_page_table_set_dirty(stasis_dirty_page_table_t * dirtyPages, Page * p) {
@ -93,15 +92,7 @@ void stasis_dirty_page_table_set_clean(stasis_dirty_page_table_t * dirtyPages, P
assert(p->dirty); assert(p->dirty);
p->dirty = 0; p->dirty = 0;
lsn_t targetLsn = dirtyPages->targetLsn;
if (e->lsn < targetLsn) {
const dpt_entry * e2 = rbmin(dirtyPages->tableByLsnAndPage);
if (!e2 || e2->lsn >= targetLsn) {
dirtyPages->targetLsn = 0;
pthread_cond_broadcast( &dirtyPages->writebackCond ); pthread_cond_broadcast( &dirtyPages->writebackCond );
}
}
dirtyPages->count--; dirtyPages->count--;
} }
@ -147,6 +138,9 @@ int stasis_dirty_page_table_flush_with_target(stasis_dirty_page_table_t * dirtyP
if(dirtyPages->flushing) { if(dirtyPages->flushing) {
pthread_cond_wait(&dirtyPages->flushDone, &dirtyPages->mutex); pthread_cond_wait(&dirtyPages->flushDone, &dirtyPages->mutex);
pthread_mutex_unlock(&dirtyPages->mutex); pthread_mutex_unlock(&dirtyPages->mutex);
// We return EAGAIN here because the other flush may have begun
// before some page that this flush is interested in was
// written.
return EAGAIN; return EAGAIN;
} }
dirtyPages->flushing = 1; dirtyPages->flushing = 1;
@ -184,14 +178,15 @@ int stasis_dirty_page_table_flush_with_target(stasis_dirty_page_table_t * dirtyP
} }
pthread_mutex_lock(&dirtyPages->mutex); pthread_mutex_lock(&dirtyPages->mutex);
dpt_entry * e = ((dpt_entry*)rbmin(dirtyPages->tableByLsnAndPage));
if (!all_flushed && if (!all_flushed &&
targetLsn < LSN_T_MAX && targetLsn < LSN_T_MAX &&
dirtyPages->count > 0 && dirtyPages->count > 0 &&
targetLsn > ((dpt_entry*)rbmin(dirtyPages->tableByLsnAndPage))->lsn ) { e && targetLsn > e->lsn ) {
struct timespec ts; struct timespec ts;
struct timeval tv; struct timeval tv;
dirtyPages->targetLsn = targetLsn;
all_flushed = 1; all_flushed = 1;
int res = gettimeofday(&tv, 0); int res = gettimeofday(&tv, 0);
@ -211,11 +206,14 @@ int stasis_dirty_page_table_flush_with_target(stasis_dirty_page_table_t * dirtyP
ts.tv_sec = tv.tv_sec; ts.tv_sec = tv.tv_sec;
ts.tv_nsec = 1000*tv.tv_usec; ts.tv_nsec = 1000*tv.tv_usec;
while ( dirtyPages->targetLsn != 0 ) { dpt_entry * e = ((dpt_entry*)rbmin(dirtyPages->tableByLsnAndPage));
while( e && targetLsn > e->lsn ) {
if (pthread_cond_timedwait(&dirtyPages->writebackCond, &dirtyPages->mutex, &ts) == ETIMEDOUT) { if (pthread_cond_timedwait(&dirtyPages->writebackCond, &dirtyPages->mutex, &ts) == ETIMEDOUT) {
all_flushed = 0; all_flushed = 0;
break; break;
} }
e = ((dpt_entry*)rbmin(dirtyPages->tableByLsnAndPage));
} }
} }
} while(!all_flushed); } while(!all_flushed);
@ -226,9 +224,6 @@ int stasis_dirty_page_table_flush_with_target(stasis_dirty_page_table_t * dirtyP
pthread_mutex_unlock(&dirtyPages->mutex); pthread_mutex_unlock(&dirtyPages->mutex);
// if(strides < 5) { DEBUG("strides: %d dirtyCount = %lld\n", strides, stasis_dirty_page_table_dirty_count(dirtyPages)); }
return 0; return 0;
} }
@ -308,7 +303,6 @@ stasis_dirty_page_table_t * stasis_dirty_page_table_init() {
pthread_mutex_init(&ret->mutex, 0); pthread_mutex_init(&ret->mutex, 0);
pthread_cond_init(&ret->flushDone, 0); pthread_cond_init(&ret->flushDone, 0);
ret->flushing = 0; ret->flushing = 0;
ret->targetLsn = 0;
pthread_cond_init(&ret->writebackCond, 0); pthread_cond_init(&ret->writebackCond, 0);
return ret; return ret;
} }