/*
** Sync an jt-file.
*/
static int jtSync(sqlite3_file *pFile, int flags){
jt_file *p = (jt_file *)pFile;
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
int rc;
jt_file *pMain; /* The associated database file */
/* The journal file is being synced. At this point, we inspect the
** contents of the file up to this point and set each bit in the
** jt_file.pWritable bitvec of the main database file associated with
** this journal file.
*/
pMain = locateDatabaseHandle(p->zName);
assert(pMain);
/* Set the bitvec values */
if( pMain->pWritable ){
pMain->nSync++;
rc = readJournalFile(p, pMain);
if( rc!=SQLITE_OK ){
return rc;
}
}
}
return sqlite3OsSync(p->pReal, flags);
}
/*
** Sync the file.
*/
static int jrnlSync(sqlite3_file *pJfd, int flags){
int rc;
JournalFile *p = (JournalFile *)pJfd;
rc = createFile(p);
if( rc==SQLITE_OK ){
rc = sqlite3OsSync(p->pReal, flags);
}
return rc;
}
/*
** Sync the file.
*/
static int jrnlSync(sqlite3_file *pJfd, int flags){
int rc;
JournalFile *p = (JournalFile *)pJfd;
if( p->pReal ){
rc = sqlite3OsSync(p->pReal, flags);
}else{
rc = SQLITE_OK;
}
return rc;
}
/*
** Sync an tvfs-file.
*/
static int tvfsSync(sqlite3_file *pFile, int flags){
int rc = SQLITE_OK;
TestvfsFd *pFd = tvfsGetFd(pFile);
Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
if( p->pScript && p->mask&TESTVFS_SYNC_MASK ){
char *zFlags;
switch( flags ){
case SQLITE_SYNC_NORMAL:
zFlags = "normal";
break;
case SQLITE_SYNC_FULL:
zFlags = "full";
break;
case SQLITE_SYNC_NORMAL|SQLITE_SYNC_DATAONLY:
zFlags = "normal|dataonly";
break;
case SQLITE_SYNC_FULL|SQLITE_SYNC_DATAONLY:
zFlags = "full|dataonly";
break;
default:
assert(0);
}
tvfsExecTcl(p, "xSync",
Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId,
Tcl_NewStringObj(zFlags, -1), 0
);
tvfsResultCode(p, &rc);
}
if( rc==SQLITE_OK && tvfsInjectFullerr(p) ) rc = SQLITE_FULL;
if( rc==SQLITE_OK ){
rc = sqlite3OsSync(pFd->pReal, flags);
}
return rc;
}
static int jtSync(sqlite3_file *pFile, int flags){
jt_file *p = (jt_file *)pFile;
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
int rc;
jt_file *pMain;
pMain = locateDatabaseHandle(p->zName);
assert(pMain);
if( pMain->pWritable ){
pMain->nSync++;
rc = readJournalFile(p, pMain);
if( rc!=SQLITE_OK ){
return rc;
}
}
}
return sqlite3OsSync(p->pReal, flags);
}
/*
** Sync an devsym-file.
*/
static int devsymSync(sqlite3_file *pFile, int flags){
devsym_file *p = (devsym_file *)pFile;
return sqlite3OsSync(p->pReal, flags);
}
/*
** A read or write transaction may or may not be active on database handle
** db. If a transaction is active, commit it. If there is a
** write-transaction spanning more than one database file, this routine
** takes care of the master journal trickery.
*/
static int vdbeCommit(sqlite3 *db){
int i;
int nTrans = 0; /* Number of databases with an active write-transaction */
int rc = SQLITE_OK;
int needXcommit = 0;
for(i=0; i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( pBt && sqlite3BtreeIsInTrans(pBt) ){
needXcommit = 1;
if( i!=1 ) nTrans++;
}
}
/* If there are any write-transactions at all, invoke the commit hook */
if( needXcommit && db->xCommitCallback ){
int rc;
sqlite3SafetyOff(db);
rc = db->xCommitCallback(db->pCommitArg);
sqlite3SafetyOn(db);
if( rc ){
return SQLITE_CONSTRAINT;
}
}
/* The simple case - no more than one database file (not counting the
** TEMP database) has a transaction active. There is no need for the
** master-journal.
**
** If the return value of sqlite3BtreeGetFilename() is a zero length
** string, it means the main database is :memory:. In that case we do
** not support atomic multi-file commits, so use the simple case then
** too.
*/
if( 0==strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt)) || nTrans<=1 ){
for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( pBt ){
rc = sqlite3BtreeSync(pBt, 0);
}
}
/* Do the commit only if all databases successfully synced */
if( rc==SQLITE_OK ){
for(i=0; i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( pBt ){
sqlite3BtreeCommit(pBt);
}
}
}
}
/* The complex case - There is a multi-file write-transaction active.
** This requires a master journal file to ensure the transaction is
** committed atomicly.
*/
else{
char *zMaster = 0; /* File-name for the master journal */
char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
OsFile master;
/* Select a master journal file name */
do {
u32 random;
sqliteFree(zMaster);
sqlite3Randomness(sizeof(random), &random);
zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
if( !zMaster ){
return SQLITE_NOMEM;
}
}while( sqlite3OsFileExists(zMaster) );
/* Open the master journal. */
memset(&master, 0, sizeof(master));
rc = sqlite3OsOpenExclusive(zMaster, &master, 0);
if( rc!=SQLITE_OK ){
sqliteFree(zMaster);
return rc;
}
/* Write the name of each database file in the transaction into the new
** master journal file. If an error occurs at this point close
** and delete the master journal file. All the individual journal files
** still have 'null' as the master journal pointer, so they will roll
** back independantly if a failure occurs.
*/
for(i=0; i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( i==1 ) continue; /* Ignore the TEMP database */
if( pBt && sqlite3BtreeIsInTrans(pBt) ){
char const *zFile = sqlite3BtreeGetJournalname(pBt);
if( zFile[0]==0 ) continue; /* Ignore :memory: databases */
rc = sqlite3OsWrite(&master, zFile, strlen(zFile)+1);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&master);
sqlite3OsDelete(zMaster);
sqliteFree(zMaster);
return rc;
}
}
}
/* Sync the master journal file. Before doing this, open the directory
** the master journal file is store in so that it gets synced too.
*/
zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
rc = sqlite3OsOpenDirectory(zMainFile, &master);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&master);
sqlite3OsDelete(zMaster);
sqliteFree(zMaster);
return rc;
}
rc = sqlite3OsSync(&master);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&master);
sqliteFree(zMaster);
return rc;
}
/* Sync all the db files involved in the transaction. The same call
** sets the master journal pointer in each individual journal. If
** an error occurs here, do not delete the master journal file.
**
** If the error occurs during the first call to sqlite3BtreeSync(),
** then there is a chance that the master journal file will be
** orphaned. But we cannot delete it, in case the master journal
** file name was written into the journal file before the failure
** occured.
*/
for(i=0; i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( pBt && sqlite3BtreeIsInTrans(pBt) ){
rc = sqlite3BtreeSync(pBt, zMaster);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&master);
sqliteFree(zMaster);
return rc;
}
}
}
sqlite3OsClose(&master);
/* Delete the master journal file. This commits the transaction. After
** doing this the directory is synced again before any individual
** transaction files are deleted.
*/
rc = sqlite3OsDelete(zMaster);
assert( rc==SQLITE_OK );
sqliteFree(zMaster);
zMaster = 0;
rc = sqlite3OsSyncDirectory(zMainFile);
if( rc!=SQLITE_OK ){
/* This is not good. The master journal file has been deleted, but
** the directory sync failed. There is no completely safe course of
** action from here. The individual journals contain the name of the
** master journal file, but there is no way of knowing if that
** master journal exists now or if it will exist after the operating
** system crash that may follow the fsync() failure.
*/
assert(0);
sqliteFree(zMaster);
return rc;
}
/* All files and directories have already been synced, so the following
** calls to sqlite3BtreeCommit() are only closing files and deleting
** journals. If something goes wrong while this is happening we don't
** really care. The integrity of the transaction is already guaranteed,
** but some stray 'cold' journals may be lying around. Returning an
** error code won't help matters.
*/
for(i=0; i<db->nDb; i++){
Btree *pBt = db->aDb[i].pBt;
if( pBt ){
sqlite3BtreeCommit(pBt);
}
}
}
return rc;
}
/*
** This procedure runs in a separate thread, reading messages off of the
** write queue and processing them one by one.
**
** If async.writerHaltNow is true, then this procedure exits
** after processing a single message.
**
** If async.writerHaltWhenIdle is true, then this procedure exits when
** the write queue is empty.
**
** If both of the above variables are false, this procedure runs
** indefinately, waiting for operations to be added to the write queue
** and processing them in the order in which they arrive.
**
** An artifical delay of async.ioDelay milliseconds is inserted before
** each write operation in order to simulate the effect of a slow disk.
**
** Only one instance of this procedure may be running at a time.
*/
static void *asyncWriterThread(void *NotUsed){
AsyncWrite *p = 0;
int rc = SQLITE_OK;
int holdingMutex = 0;
if( pthread_mutex_trylock(&async.writerMutex) ){
return 0;
}
while( async.writerHaltNow==0 ){
OsFile *pBase = 0;
if( !holdingMutex ){
pthread_mutex_lock(&async.queueMutex);
}
while( (p = async.pQueueFirst)==0 ){
pthread_cond_broadcast(&async.emptySignal);
if( async.writerHaltWhenIdle ){
pthread_mutex_unlock(&async.queueMutex);
break;
}else{
ASYNC_TRACE(("IDLE\n"));
pthread_cond_wait(&async.queueSignal, &async.queueMutex);
ASYNC_TRACE(("WAKEUP\n"));
}
}
if( p==0 ) break;
holdingMutex = 1;
/* Right now this thread is holding the mutex on the write-op queue.
** Variable 'p' points to the first entry in the write-op queue. In
** the general case, we hold on to the mutex for the entire body of
** the loop.
**
** However in the cases enumerated below, we relinquish the mutex,
** perform the IO, and then re-request the mutex before removing 'p' from
** the head of the write-op queue. The idea is to increase concurrency with
** sqlite threads.
**
** * An ASYNC_CLOSE operation.
** * An ASYNC_OPENEXCLUSIVE operation. For this one, we relinquish
** the mutex, call the underlying xOpenExclusive() function, then
** re-aquire the mutex before seting the AsyncFile.pBaseRead
** variable.
** * ASYNC_SYNC and ASYNC_WRITE operations, if
** SQLITE_ASYNC_TWO_FILEHANDLES was set at compile time and two
** file-handles are open for the particular file being "synced".
*/
if( async.ioError!=SQLITE_OK && p->op!=ASYNC_CLOSE ){
p->op = ASYNC_NOOP;
}
if( p->pFile ){
pBase = p->pFile->pBaseWrite;
if(
p->op==ASYNC_CLOSE ||
p->op==ASYNC_OPENEXCLUSIVE ||
(pBase && (p->op==ASYNC_SYNC || p->op==ASYNC_WRITE) )
){
pthread_mutex_unlock(&async.queueMutex);
holdingMutex = 0;
}
if( !pBase ){
pBase = p->pFile->pBaseRead;
}
}
switch( p->op ){
case ASYNC_NOOP:
break;
case ASYNC_WRITE:
assert( pBase );
ASYNC_TRACE(("WRITE %s %d bytes at %d\n",
p->pFile->zName, p->nByte, p->iOffset));
rc = sqlite3OsSeek(pBase, p->iOffset);
if( rc==SQLITE_OK ){
rc = sqlite3OsWrite(pBase, (const void *)(p->zBuf), p->nByte);
}
break;
case ASYNC_SYNC:
assert( pBase );
ASYNC_TRACE(("SYNC %s\n", p->pFile->zName));
rc = sqlite3OsSync(pBase, p->nByte);
break;
case ASYNC_TRUNCATE:
assert( pBase );
ASYNC_TRACE(("TRUNCATE %s to %d bytes\n", p->pFile->zName, p->iOffset));
rc = sqlite3OsTruncate(pBase, p->iOffset);
break;
case ASYNC_CLOSE:
ASYNC_TRACE(("CLOSE %s\n", p->pFile->zName));
sqlite3OsClose(&p->pFile->pBaseWrite);
sqlite3OsClose(&p->pFile->pBaseRead);
sqlite3OsFree(p->pFile);
break;
case ASYNC_OPENDIRECTORY:
assert( pBase );
ASYNC_TRACE(("OPENDIR %s\n", p->zBuf));
sqlite3OsOpenDirectory(pBase, p->zBuf);
break;
case ASYNC_SETFULLSYNC:
assert( pBase );
ASYNC_TRACE(("SETFULLSYNC %s %d\n", p->pFile->zName, p->nByte));
sqlite3OsSetFullSync(pBase, p->nByte);
break;
case ASYNC_DELETE:
ASYNC_TRACE(("DELETE %s\n", p->zBuf));
rc = xOrigDelete(p->zBuf);
break;
case ASYNC_SYNCDIRECTORY:
ASYNC_TRACE(("SYNCDIR %s\n", p->zBuf));
rc = xOrigSyncDirectory(p->zBuf);
break;
case ASYNC_OPENEXCLUSIVE: {
AsyncFile *pFile = p->pFile;
int delFlag = ((p->iOffset)?1:0);
OsFile *pBase = 0;
ASYNC_TRACE(("OPEN %s delFlag=%d\n", p->zBuf, delFlag));
assert(pFile->pBaseRead==0 && pFile->pBaseWrite==0);
rc = xOrigOpenExclusive(p->zBuf, &pBase, delFlag);
assert( holdingMutex==0 );
pthread_mutex_lock(&async.queueMutex);
holdingMutex = 1;
if( rc==SQLITE_OK ){
pFile->pBaseRead = pBase;
}
break;
}
default: assert(!"Illegal value for AsyncWrite.op");
}
/* If we didn't hang on to the mutex during the IO op, obtain it now
** so that the AsyncWrite structure can be safely removed from the
** global write-op queue.
*/
if( !holdingMutex ){
pthread_mutex_lock(&async.queueMutex);
holdingMutex = 1;
}
/* ASYNC_TRACE(("UNLINK %p\n", p)); */
if( p==async.pQueueLast ){
async.pQueueLast = 0;
}
async.pQueueFirst = p->pNext;
sqlite3OsFree(p);
assert( holdingMutex );
/* An IO error has occured. We cannot report the error back to the
** connection that requested the I/O since the error happened
** asynchronously. The connection has already moved on. There
** really is nobody to report the error to.
**
** The file for which the error occured may have been a database or
** journal file. Regardless, none of the currently queued operations
** associated with the same database should now be performed. Nor should
** any subsequently requested IO on either a database or journal file
** handle for the same database be accepted until the main database
** file handle has been closed and reopened.
**
** Furthermore, no further IO should be queued or performed on any file
** handle associated with a database that may have been part of a
** multi-file transaction that included the database associated with
** the IO error (i.e. a database ATTACHed to the same handle at some
** point in time).
*/
if( rc!=SQLITE_OK ){
async.ioError = rc;
}
/* Drop the queue mutex before continuing to the next write operation
** in order to give other threads a chance to work with the write queue.
*/
if( !async.pQueueFirst || !async.ioError ){
sqlite3ApiExit(0, 0);
pthread_mutex_unlock(&async.queueMutex);
holdingMutex = 0;
if( async.ioDelay>0 ){
sqlite3OsSleep(async.ioDelay);
}else{
sched_yield();
}
}
}
pthread_mutex_unlock(&async.writerMutex);
return 0;
}
