stasis-aries-wal/src/lladd/bufferManager.c

/*---
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---*/
/*******************************
 * $Id$
 *
 * implementation of the page buffer
 * *************************************************/

#include <config.h>
#include <lladd/common.h>

#include <assert.h>
#include <stdio.h>

#include <lladd/bufferManager.h>
#include "blobManager.h"
#include <lladd/pageCache.h>
#include <lladd/logger/logWriter.h>

#include <lladd/page.h>

static FILE * stable = NULL;

/** 
    This function blocks until there are no events pending for this page.
*/
static void finalize(Page * page);



/**
   Invariant: This lock should be held while updating lastFreepage, or
   while performing any operation that may decrease the amount of
   freespace in the page that lastFreepage refers to.  

   Since pageCompact and pageDeRalloc may only increase this value,
   they do not need to hold this lock.  Since bufferManager is the
   only place where pageRalloc is called, pageRalloc does not obtain
   this lock.
*/

static pthread_mutex_t lastFreepage_mutex;
static unsigned int lastFreepage = 0;

/**
 * @param pageid ID of the page you want to load
 * @return fully formed Page type
 * @return page with -1 ID if page not found
 */
Page * loadPage(int pageid); 



/* ** File I/O functions ** */
/* Defined in blobManager.c, but don't want to export this in any public .h files... */
long myFseek(FILE * f, long offset, int whence);

void pageRead(Page *ret) {
  long fileSize = myFseek(stable, 0, SEEK_END);
  long pageoffset = ret->id * PAGE_SIZE;
  long offset;

  DEBUG("Reading page %d\n", ret->id);

  if(!ret->memAddr) {
    ret->memAddr = malloc(PAGE_SIZE);
  }
  assert(ret->memAddr);
  
  if ((ret->id)*PAGE_SIZE >= fileSize) {
    myFseek(stable, (1+ ret->id) * PAGE_SIZE -1, SEEK_SET);
    if(1 != fwrite("", 1, 1, stable)) {
      if(feof(stable)) { printf("Unexpected eof extending storefile!\n"); fflush(NULL); abort(); }
      if(ferror(stable)) { printf("Error extending storefile! %d", ferror(stable)); fflush(NULL); abort(); }
    }

  }
  offset = myFseek(stable, pageoffset, SEEK_SET);
  assert(offset == pageoffset);

  if(1 != fread(ret->memAddr, PAGE_SIZE, 1, stable)) {
                                                                                                                 
    if(feof(stable)) { printf("Unexpected eof reading!\n"); fflush(NULL); abort(); }
    if(ferror(stable)) { printf("Error reading stream! %d", ferror(stable)); fflush(NULL); abort(); }
                                                                                                                 
  }

}

void pageWrite(Page * ret) {

  long pageoffset = ret->id * PAGE_SIZE;
  long offset = myFseek(stable, pageoffset, SEEK_SET);
  assert(offset == pageoffset);
  assert(ret->memAddr);

  DEBUG("Writing page %d\n", ret->id);

  if(flushedLSN() < pageReadLSN(ret)) {
    DEBUG("pageWrite is calling syncLog()!\n");
    syncLog();
  }

  finalize(ret);

  if(1 != fwrite(ret->memAddr, PAGE_SIZE, 1, stable)) {
                                                                                                                 
    if(feof(stable)) { printf("Unexpected eof writing!\n"); fflush(NULL); abort(); }
    if(ferror(stable)) { printf("Error writing stream! %d", ferror(stable)); fflush(NULL); abort(); }
                                                                                                                 
  }


}

static void openPageFile() {

  DEBUG("Opening storefile.\n");
  if( ! (stable = fopen(STORE_FILE, "r+"))) { /* file may not exist */
    byte* zero = calloc(1, PAGE_SIZE);

    if(!(stable = fopen(STORE_FILE, "w+"))) { perror("Couldn't open or create store file"); abort(); }

    /* Write out one page worth of zeros to get started. */
    
    if(1 != fwrite(zero, PAGE_SIZE, 1, stable)) { assert (0); }

    free(zero);
  }
  
  lastFreepage = 0;
  pthread_mutex_init(&lastFreepage_mutex , NULL);

  DEBUG("storefile opened.\n");

}
static void closePageFile() {

  int ret = fclose(stable);
  assert(!ret);
  stable = NULL;
}

int bufInit() {

	stable = NULL;
	pageInit();
	openPageFile();
	pageCacheInit();
	openBlobStore();

	return 0;
}

void bufDeinit() {

	closeBlobStore();
	pageCacheDeinit();
	closePageFile();

	return;
}
/**
    Just close file descriptors, don't do any other clean up. (For
    testing.)
*/
void simulateBufferManagerCrash() {
  closeBlobStore();
  closePageFile();
  /*  close(stable);
      stable = -1;*/

}

/* ** No file I/O below this line. ** */

Page * loadPage (int pageid) {
	return loadPagePtr(pageid);
}

Page * lastRallocPage = 0;


recordid ralloc(int xid, /*lsn_t lsn,*/ long size) {
  
  recordid ret;
  Page * p;
  
  DEBUG("Rallocing record of size %ld\n", (long int)size);
  
  assert(size < BLOB_THRESHOLD_SIZE || size == BLOB_SLOT);
  
  pthread_mutex_lock(&lastFreepage_mutex);
  
  while(freespace(p = loadPage(lastFreepage)) < size ) { lastFreepage++; }
  
  ret = pageRalloc(p, size);
    
  pthread_mutex_unlock(&lastFreepage_mutex);
  
  DEBUG("alloced rid = {%d, %d, %ld}\n", ret.page, ret.slot, ret.size);

  return ret;
}

void slotRalloc(int pageid, lsn_t lsn, recordid rid) {
  Page * loadedPage = loadPage(rid.page);
  pageSlotRalloc(loadedPage, lsn, rid);
}

long readLSN(int pageid) {

	return pageReadLSN(loadPage(pageid));
}

void writeRecord(int xid, lsn_t lsn, recordid rid, const void *dat) {

  Page *p;
  
  if(rid.size > BLOB_THRESHOLD_SIZE) {
    DEBUG("Writing blob.\n");
    writeBlob(xid, lsn, rid, dat);

  } else {
    DEBUG("Writing record.\n");
    p = loadPagePtr(rid.page);
    assert( (p->id == rid.page) && (p->memAddr != NULL) );	
    /** @todo This assert should be here, but the tests are broken, so it causes bogus failures. */
    /*assert(pageReadLSN(*p) <= lsn);*/
    
    /** @todo Should pageWriteRecord take an LSN (so it can do the locking?) */
    /*    pageWriteRecord(xid, *p, rid, dat);
    p->LSN = lsn;
    pageWriteLSN(*p); */
    pageWriteRecord(xid, p, rid, lsn, dat);
    
  }
}

void readRecord(int xid, recordid rid, void *buf) {
  if(rid.size > BLOB_THRESHOLD_SIZE) {
    DEBUG("Reading blob. xid = %d rid = { %d %d %ld } buf = %x\n", 
	  xid, rid.page, rid.slot, rid.size, (unsigned int)buf);
    readBlob(xid, rid, buf);
  } else {
    DEBUG("Reading record xid = %d rid = { %d %d %ld } buf = %x\n", 
	  xid, rid.page, rid.slot, rid.size, (unsigned int)buf);
    pageReadRecord(xid, loadPage(rid.page), rid, buf);
  }
}

int bufTransCommit(int xid, lsn_t lsn) {

  commitBlobs(xid);
  pageCommit(xid);

  return 0;
}

int bufTransAbort(int xid, lsn_t lsn) {

  abortBlobs(xid);  /* abortBlobs doesn't write any log entries, so it doesn't need the lsn. */
  pageAbort(xid);

  return 0;
}

void addPendingEvent(int pageid){
  
  Page * p = loadPage(pageid);

  pthread_mutex_lock(&(p->pending_mutex));

  assert(!(p->waiting));

  p->pending++;

  pthread_mutex_unlock(&(p->pending_mutex));

}

/** @todo as implemented, loadPage() ... doOperation is not atomic!*/
void removePendingEvent(int pageid) {
  
  Page * p = loadPage(pageid);

  pthread_mutex_lock(&(p->pending_mutex));

  p->pending--;
  
  assert(p->pending >= 0);

  if(p->waiting && !p->pending) {
    assert(p->waiting == 1);
    pthread_cond_signal(&(p->noMorePending));
  }

  pthread_mutex_unlock(&(p->pending_mutex));
}


static void finalize(Page * p) {
  pthread_mutex_lock(&(p->pending_mutex));
  p->waiting++;

  while(p->pending) {
    
    pthread_cond_wait(&(p->noMorePending), &(p->pending_mutex));
  }

  pthread_mutex_unlock(&(p->pending_mutex)); 

  return;
}


void setSlotType(int pageid, int slot, int type) {
  Page * p = loadPage(pageid);
  pageSetSlotType(p, slot, type);
}