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Overview
| Comment: | Do not hold the shared-memory mutex in os_unix.c if returning NULL. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | wal-incr-ckpt |
| Files: | files | file ages | folders |
| SHA1: |
9622dd468c8914262e9d8bd8dbca9e22 |
| User & Date: | dan 2010-06-01 11:08:57 |
Context
|
2010-06-01
| ||
| 12:58 | Fix an off-by-one boundary-value issue in walCleanupHash(). (check-in: f039552e user: drh tags: wal-incr-ckpt) | |
| 11:08 | Do not hold the shared-memory mutex in os_unix.c if returning NULL. (check-in: 9622dd46 user: dan tags: wal-incr-ckpt) | |
| 10:44 | If the checkpoint fails to obtain an exclusive lock on one of the read-lock bytes, do not consider this an error. (check-in: 9e95e357 user: dan tags: wal-incr-ckpt) | |
Changes
Changes to src/os_unix.c.
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/* Remove connection p from the set of connections associated
** with pShmNode */
sqlite3_mutex_enter(pShmNode->mutex);
for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
*pp = p->pNext;
/* Free the connection p */
sqlite3_free(p);
pDbFd->pShm = 0;
sqlite3_mutex_leave(pShmNode->mutex);
/* If pShmNode->nRef has reached 0, then close the underlying
** shared-memory file, too */
unixEnterMutex();
................................................................................
}
rc = ftruncate(pShmNode->h, reqSize);
reqSize = -1;
}
return rc;
}
/*
** Map the shared storage into memory.
**
** If reqMapSize is positive, then an attempt is made to make the
** mapping at least reqMapSize bytes in size. However, the mapping
** will never be larger than the size of the underlying shared memory
................................................................................
pShmNode->pMMapBuf = 0;
pShmNode->szMap = 0;
}
}
*pNewMapSize = pShmNode->szMap;
*ppBuf = pShmNode->pMMapBuf;
sqlite3_mutex_leave(pShmNode->mutex);
return rc;
}
/*
** Release the lock held on the shared memory segment to that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int unixShmRelease(sqlite3_file *fd){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p = pDbFd->pShm;
if( p->hasMutexBuf ){
assert( sqlite3_mutex_notheld(p->pShmNode->mutex) );
sqlite3_mutex_leave(p->pShmNode->mutexBuf);
p->hasMutexBuf = 0;
}
return SQLITE_OK;
}
/*
** Change the lock state for a shared-memory segment.
**
** Note that the relationship between SHAREd and EXCLUSIVE locks is a little
** different here than in posix. In xShmLock(), one can go from unlocked
** to shared and back or from unlocked to exclusive and back. But one may
|
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3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 .... 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 .... 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 |
/* Remove connection p from the set of connections associated
** with pShmNode */
sqlite3_mutex_enter(pShmNode->mutex);
for(pp=&pShmNode->pFirst; (*pp)!=p; pp = &(*pp)->pNext){}
*pp = p->pNext;
/* Free the connection p */
assert( p->hasMutexBuf==0 );
sqlite3_free(p);
pDbFd->pShm = 0;
sqlite3_mutex_leave(pShmNode->mutex);
/* If pShmNode->nRef has reached 0, then close the underlying
** shared-memory file, too */
unixEnterMutex();
................................................................................
}
rc = ftruncate(pShmNode->h, reqSize);
reqSize = -1;
}
return rc;
}
/*
** Release the lock held on the shared memory segment to that other
** threads are free to resize it if necessary.
**
** If the lock is not currently held, this routine is a harmless no-op.
**
** If the shared-memory object is in lock state RECOVER, then we do not
** really want to release the lock, so in that case too, this routine
** is a no-op.
*/
static int unixShmRelease(sqlite3_file *fd){
unixFile *pDbFd = (unixFile*)fd;
unixShm *p = pDbFd->pShm;
if( p->hasMutexBuf ){
assert( sqlite3_mutex_notheld(p->pShmNode->mutex) );
sqlite3_mutex_leave(p->pShmNode->mutexBuf);
p->hasMutexBuf = 0;
}
return SQLITE_OK;
}
/*
** Map the shared storage into memory.
**
** If reqMapSize is positive, then an attempt is made to make the
** mapping at least reqMapSize bytes in size. However, the mapping
** will never be larger than the size of the underlying shared memory
................................................................................
pShmNode->pMMapBuf = 0;
pShmNode->szMap = 0;
}
}
*pNewMapSize = pShmNode->szMap;
*ppBuf = pShmNode->pMMapBuf;
sqlite3_mutex_leave(pShmNode->mutex);
if( *ppBuf==0 ){
/* Do not hold the mutex if a NULL pointer is being returned. */
unixShmRelease(fd);
}
return rc;
}
/*
** Change the lock state for a shared-memory segment.
**
** Note that the relationship between SHAREd and EXCLUSIVE locks is a little
** different here than in posix. In xShmLock(), one can go from unlocked
** to shared and back or from unlocked to exclusive and back. But one may
|