diff options
Diffstat (limited to 'src/os_unix.c')
| -rw-r--r-- | src/os_unix.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/src/os_unix.c b/src/os_unix.c index 927b9e1c5..16cb935de 100644 --- a/src/os_unix.c +++ b/src/os_unix.c @@ -248,6 +248,7 @@ static pid_t randomnessPid = 0; #define UNIXFILE_URI 0x40 /* Filename might have query parameters */ #define UNIXFILE_NOLOCK 0x80 /* Do no file locking */ #define UNIXFILE_WARNED 0x0100 /* verifyDbFile() warnings issued */ +#define UNIXFILE_BLOCK 0x0200 /* Next SHM lock might block */ /* ** Include code that is common to all os_*.c files @@ -4090,15 +4091,17 @@ struct unixShm { ** otherwise. */ static int unixShmSystemLock( - unixShmNode *pShmNode, /* Apply locks to this open shared-memory segment */ + unixFile *pFile, /* Open connection to the WAL file */ int lockType, /* F_UNLCK, F_RDLCK, or F_WRLCK */ int ofst, /* First byte of the locking range */ int n /* Number of bytes to lock */ ){ - struct flock f; /* The posix advisory locking structure */ - int rc = SQLITE_OK; /* Result code form fcntl() */ + unixShmNode *pShmNode; /* Apply locks to this open shared-memory segment */ + struct flock f; /* The posix advisory locking structure */ + int rc = SQLITE_OK; /* Result code form fcntl() */ /* Access to the unixShmNode object is serialized by the caller */ + pShmNode = pFile->pInode->pShmNode; assert( sqlite3_mutex_held(pShmNode->mutex) || pShmNode->nRef==0 ); /* Shared locks never span more than one byte */ @@ -4108,6 +4111,7 @@ static int unixShmSystemLock( assert( n>=1 && n<SQLITE_SHM_NLOCK ); if( pShmNode->h>=0 ){ + int lkType; /* Initialize the locking parameters */ memset(&f, 0, sizeof(f)); f.l_type = lockType; @@ -4115,8 +4119,10 @@ static int unixShmSystemLock( f.l_start = ofst; f.l_len = n; - rc = osFcntl(pShmNode->h, F_SETLK, &f); + lkType = (pFile->ctrlFlags & UNIXFILE_BLOCK)!=0 ? F_SETLKW : F_SETLK; + rc = osFcntl(pShmNode->h, lkType, &f); rc = (rc!=(-1)) ? SQLITE_OK : SQLITE_BUSY; + pFile->ctrlFlags &= ~UNIXFILE_BLOCK; } /* Update the global lock state and do debug tracing */ @@ -4326,13 +4332,13 @@ static int unixOpenSharedMemory(unixFile *pDbFd){ ** If not, truncate the file to zero length. */ rc = SQLITE_OK; - if( unixShmSystemLock(pShmNode, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){ + if( unixShmSystemLock(pDbFd, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){ if( robust_ftruncate(pShmNode->h, 0) ){ rc = unixLogError(SQLITE_IOERR_SHMOPEN, "ftruncate", zShmFilename); } } if( rc==SQLITE_OK ){ - rc = unixShmSystemLock(pShmNode, F_RDLCK, UNIX_SHM_DMS, 1); + rc = unixShmSystemLock(pDbFd, F_RDLCK, UNIX_SHM_DMS, 1); } if( rc ) goto shm_open_err; } @@ -4564,7 +4570,7 @@ static int unixShmLock( /* Unlock the system-level locks */ if( (mask & allMask)==0 ){ - rc = unixShmSystemLock(pShmNode, F_UNLCK, ofst+UNIX_SHM_BASE, n); + rc = unixShmSystemLock(pDbFd, F_UNLCK, ofst+UNIX_SHM_BASE, n); }else{ rc = SQLITE_OK; } @@ -4592,7 +4598,7 @@ static int unixShmLock( /* Get shared locks at the system level, if necessary */ if( rc==SQLITE_OK ){ if( (allShared & mask)==0 ){ - rc = unixShmSystemLock(pShmNode, F_RDLCK, ofst+UNIX_SHM_BASE, n); + rc = unixShmSystemLock(pDbFd, F_RDLCK, ofst+UNIX_SHM_BASE, n); }else{ rc = SQLITE_OK; } @@ -4617,7 +4623,7 @@ static int unixShmLock( ** also mark the local connection as being locked. */ if( rc==SQLITE_OK ){ - rc = unixShmSystemLock(pShmNode, F_WRLCK, ofst+UNIX_SHM_BASE, n); + rc = unixShmSystemLock(pDbFd, F_WRLCK, ofst+UNIX_SHM_BASE, n); if( rc==SQLITE_OK ){ assert( (p->sharedMask & mask)==0 ); p->exclMask |= mask; @@ -7222,6 +7228,10 @@ static int proxyTransformUnixFile(unixFile *pFile, const char *path) { */ static int proxyFileControl(sqlite3_file *id, int op, void *pArg){ switch( op ){ + case SQLITE_FCNTL_WAL_BLOCK: { + id->ctrlFlags |= UNIXFILE_BLOCK; + return SQLITE_OK; + } case SQLITE_FCNTL_GET_LOCKPROXYFILE: { unixFile *pFile = (unixFile*)id; if( pFile->pMethod == &proxyIoMethods ){ |