C++ IBLOCK函数代码示例

// Lock the given inode.
void
ilock(struct inode *ip)
{
  struct buf *bp;
  struct dinode *dip;

  if(ip == 0 || ip->ref < 1)
    panic("ilock");

  acquire(&icache.lock);
  while(ip->flags & I_BUSY)
    sleep(ip, &icache.lock);
  ip->flags |= I_BUSY;
  release(&icache.lock);

  if(!(ip->flags & I_VALID)){
    bp = bread(ip->dev, IBLOCK(ip->inum));
    dip = (struct dinode*)bp->data + ip->inum%IPB;
    ip->type = dip->type;
    ip->major = dip->major;
    ip->minor = dip->minor;
    ip->nlink = dip->nlink;
    ip->size = dip->size;
    memmove(ip->addrs, dip->addrs, sizeof(ip->addrs));
    brelse(bp);
    ip->flags |= I_VALID;
    if(ip->type == 0)
      panic("ilock: no type");
  }
}

// Lock the given inode.
// Reads the inode from disk if necessary.
void ilock(struct inode* ip)
{
    struct buf* bp;
    struct dinode* dip;
    //   cprintf("ilock \n");

    if (ip == 0 || ip->ref < 1)
        panic("ilock");

    acquire(&icache.lock);
    while (ip->flags & I_BUSY)
        sleep(ip, &icache.lock);
    ip->flags |= I_BUSY;
    release(&icache.lock);

    if (!(ip->flags & I_VALID)) {
        struct superblock sb;
        sb = sbs[ip->part->number];
        // cprintf("inode inum %d , part Number %d \n",ip->inum,ip->part->number);
        bp = bread(ip->dev, IBLOCK(ip->inum, sb));
        dip = (struct dinode*)bp->data + ip->inum % IPB;
        ip->type = dip->type;
        ip->major = dip->major;
        ip->minor = dip->minor;
        ip->nlink = dip->nlink;
        ip->size = dip->size;
        memmove(ip->addrs, dip->addrs, sizeof(ip->addrs));
        brelse(bp);
        ip->flags |= I_VALID;
        if (ip->type == 0)
            panic("ilock: no type");
    }
}

//PAGEBREAK!
// Allocate a new inode with the given type on device dev.
// A free inode has a type of zero.
struct inode*
ialloc(uint dev, short type)
{
  int inum;
  struct buf *bp;
  struct dinode *dip;
  struct superblock sb;

  readsb(dev, &sb);

  for(inum = 1; inum < sb.ninodes; inum++){
    bp = bread(dev, IBLOCK(inum));
    dip = (struct dinode*)bp->data + inum%IPB;
    if(dip->type == 0){  // a free inode
      memset(dip, 0, sizeof(*dip));
      dip->type = type;
      log_write(bp);   // mark it allocated on the disk
      brelse(bp);
      return iget(dev, inum);
    }
    brelse(bp);
  }
  panic("ialloc: no inodes");
  return 0;
}

// Lock the given inode.
// Reads the inode from disk if necessary.
static void
sfs_ilock(struct inode *ip)
{
  struct sfs_inode *sin = vop_info(ip, sfs_inode);
  struct buf *bp;
  struct sfs_dinode *dip;

  if(sin == 0 || sin->ref < 1)
    panic("ilock");

  acquire(&icache.lock);
  while(sin->flags & I_BUSY)
    sleep(ip, &icache.lock);
  sin->flags |= I_BUSY;
  release(&icache.lock);
  
  if(!(sin->flags & I_VALID)){
//    cprintf("dev=%d, inum=%d\n", sin->dev, sin->inum);
    bp = bread(sin->dev, IBLOCK(sin->inum));
    dip = (struct sfs_dinode*)bp->data + sin->inum%IPB;
    sin->type = dip->type;
    sin->major = dip->major;
    sin->minor = dip->minor;
    sin->nlink = dip->nlink;
    sin->size = dip->size;
    memmove(sin->addrs, dip->addrs, sizeof(sin->addrs));
    brelse(bp);
    sin->flags |= I_VALID;
    if(sin->type == 0)
      panic("ilock: no type");
  }
}

void
rinode(uint inum, struct dinode *ip)
{
  char buf[BSIZE];
  uint bn;
  struct dinode *dip;

  bn = IBLOCK(inum, sb);
  rsect(bn, buf);
  dip = ((struct dinode*)buf) + (inum % IPB);
  *ip = *dip;
}

void
winode(uint inum, struct dinode *ip)
{
  char buf[BSIZE];
  uint bn;
  struct dinode *dip;

  bn = IBLOCK(inum);
  printf("winode %d\n", bn);
  rsect(bn, buf);
  dip = ((struct dinode*)buf) + (inum % IPB);
  *dip = *ip;
  wsect(bn, buf);
}

void
log_iupdate(struct inode *ip)
{
  struct dinode *dip;
  bp[b_index] = bread(ip->dev, IBLOCK(ip->inum));
  dip = (struct dinode*)bp[b_index]->data + ip->inum%IPB;
  dip->type = ip->type;
  dip->major = ip->major;
  dip->minor = ip->minor;
  dip->nlink = ip->nlink;
  dip->size = ip->size;
  memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
  b_index++;
}

// Copy a modified in-memory inode to disk.
void
sfs_iupdate(struct inode *ip)
{
  struct sfs_inode *sin = vop_info(ip, sfs_inode);
  struct buf *bp;
  struct sfs_dinode *dip;

  bp = bread(sin->dev, IBLOCK(sin->inum));
  dip = (struct sfs_dinode*)bp->data + sin->inum%IPB;
  dip->type = sin->type;
  dip->major = sin->major;
  dip->minor = sin->minor;
  dip->nlink = sin->nlink;
  dip->size = sin->size;
  memmove(dip->addrs, sin->addrs, sizeof(sin->addrs));
  log_write(bp);
  brelse(bp);
}

// Copy a modified in-memory inode to disk.
void
iupdate(struct inode *ip)
{
  struct buf *bp;
  struct dinode *dip;

  bp = bread(ip->dev, IBLOCK(ip->inum));
  dip = (struct dinode*)bp->data + ip->inum%IPB;
  dip->type = ip->type;
  dip->major = ip->major;
  dip->minor = ip->minor;
  dip->nlink = ip->nlink;
  dip->size = ip->size;
//  cprintf("iupdate - password in memory: %s\n",ip->password);
  dip->passwordSet = ip->passwordSet;
  memmove(dip->password, ip->password, 10);
  memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
  log_write(bp);
  brelse(bp);
}

// Copy a modified in-memory inode to disk.
void iupdate(struct inode* ip)
{

    //  cprintf("iupdate \n");

    struct buf* bp;
    struct dinode* dip;
    struct superblock sb;

    sb = sbs[ip->part->number];
    bp = bread(ip->dev, IBLOCK(ip->inum, sb));
    dip = (struct dinode*)bp->data + ip->inum % IPB;
    dip->type = ip->type;
    dip->major = ip->major;
    dip->minor = ip->minor;
    dip->nlink = ip->nlink;
    dip->size = ip->size;
    memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
    log_write(bp, ip->part->number);
    brelse(bp);
}

// Copy a modified in-memory inode to disk.
void
iupdate(struct inode *ip)
{
  struct buf *bp;
  struct dinode *dip;

  bp = bread(ip->dev, IBLOCK(ip->inum));
  dip = (struct dinode*)bp->data + ip->inum%IPB;
  dip->type = ip->type;
  dip->major = ip->major;
  dip->minor = ip->minor;
  dip->nlink = ip->nlink;
  dip->size = ip->size;
  memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
/*vvv  TASK 1.1  vvv*/
  dip->indirect2 = ip->indirect2;
/*^^^^^^^^^^^^^^^^^^*/
/*vvv  TASK 2    vvv*/
  memmove(dip->password, ip->password, sizeof(ip->password));
/*^^^^^^^^^^^^^^^^^^*/
  log_write(bp);
  brelse(bp);
}

// PAGEBREAK!
// Allocate a new inode with the given type on device dev.
// A free inode has a type of zero.
struct inode* ialloc(uint dev, short type, int partitionNumber)
{
    // cprintf("ialloc \n");
    int inum;
    struct buf* bp;
    struct dinode* dip;
    struct superblock sb;
    sb = sbs[partitionNumber];
    //  cprintf("ialloc pnumber %d , numberofnods %d \n", partitionNumber, sb.ninodes);
    for (inum = 1; inum < sb.ninodes; inum++) {
        // cprintf("checking inode %d \n", inum);
        bp = bread(dev, IBLOCK(inum, sb));
        dip = (struct dinode*)bp->data + inum % IPB;
        if (dip->type == 0) { // a free inode
            memset(dip, 0, sizeof(*dip));
            dip->type = type;
            log_write(bp, partitionNumber); // mark it allocated on the disk
            brelse(bp);
            return iget(dev, inum, partitionNumber);
        }
        brelse(bp);
    }
    panic("ialloc: no inodes");
}

/* Subroutine */ int sstein_(integer *n, real *d, real *e, integer *m, real *
	w, integer *iblock, integer *isplit, real *z, integer *ldz, real *
	work, integer *iwork, integer *ifail, integer *info)
{
/*  -- LAPACK routine (version 2.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       September 30, 1994   


    Purpose   
    =======   

    SSTEIN computes the eigenvectors of a real symmetric tridiagonal   
    matrix T corresponding to specified eigenvalues, using inverse   
    iteration.   

    The maximum number of iterations allowed for each eigenvector is   
    specified by an internal parameter MAXITS (currently set to 5).   

    Arguments   
    =========   

    N       (input) INTEGER   
            The order of the matrix.  N >= 0.   

    D       (input) REAL array, dimension (N)   
            The n diagonal elements of the tridiagonal matrix T.   

    E       (input) REAL array, dimension (N)   
            The (n-1) subdiagonal elements of the tridiagonal matrix   
            T, in elements 1 to N-1.  E(N) need not be set.   

    M       (input) INTEGER   
            The number of eigenvectors to be found.  0 <= M <= N.   

    W       (input) REAL array, dimension (N)   
            The first M elements of W contain the eigenvalues for   
            which eigenvectors are to be computed.  The eigenvalues   
            should be grouped by split-off block and ordered from   
            smallest to largest within the block.  ( The output array   
            W from SSTEBZ with ORDER = 'B' is expected here. )   

    IBLOCK  (input) INTEGER array, dimension (N)   
            The submatrix indices associated with the corresponding   
            eigenvalues in W; IBLOCK(i)=1 if eigenvalue W(i) belongs to   
            the first submatrix from the top, =2 if W(i) belongs to   
            the second submatrix, etc.  ( The output array IBLOCK   
            from SSTEBZ is expected here. )   

    ISPLIT  (input) INTEGER array, dimension (N)   
            The splitting points, at which T breaks up into submatrices. 
  
            The first submatrix consists of rows/columns 1 to   
            ISPLIT( 1 ), the second of rows/columns ISPLIT( 1 )+1   
            through ISPLIT( 2 ), etc.   
            ( The output array ISPLIT from SSTEBZ is expected here. )   

    Z       (output) REAL array, dimension (LDZ, M)   
            The computed eigenvectors.  The eigenvector associated   
            with the eigenvalue W(i) is stored in the i-th column of   
            Z.  Any vector which fails to converge is set to its current 
  
            iterate after MAXITS iterations.   

    LDZ     (input) INTEGER   
            The leading dimension of the array Z.  LDZ >= max(1,N).   

    WORK    (workspace) REAL array, dimension (5*N)   

    IWORK   (workspace) INTEGER array, dimension (N)   

    IFAIL   (output) INTEGER array, dimension (M)   
            On normal exit, all elements of IFAIL are zero.   
            If one or more eigenvectors fail to converge after   
            MAXITS iterations, then their indices are stored in   
            array IFAIL.   

    INFO    (output) INTEGER   
            = 0: successful exit.   
            < 0: if INFO = -i, the i-th argument had an illegal value   
            > 0: if INFO = i, then i eigenvectors failed to converge   
                 in MAXITS iterations.  Their indices are stored in   
                 array IFAIL.   

    Internal Parameters   
    ===================   

    MAXITS  INTEGER, default = 5   
            The maximum number of iterations performed.   

    EXTRA   INTEGER, default = 2   
            The number of iterations performed after norm growth   
            criterion is satisfied, should be at least 1.   

    ===================================================================== 
  


       Test the input parameters.   
//.........这里部分代码省略.........

/* Subroutine */ int sstebz_(char *range, char *order, integer *n, real *vl, 
	real *vu, integer *il, integer *iu, real *abstol, real *d, real *e, 
	integer *m, integer *nsplit, real *w, integer *iblock, integer *
	isplit, real *work, integer *iwork, integer *info)
{
/*  -- LAPACK routine (version 2.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       September 30, 1994   


    Purpose   
    =======   

    SSTEBZ computes the eigenvalues of a symmetric tridiagonal   
    matrix T.  The user may ask for all eigenvalues, all eigenvalues   
    in the half-open interval (VL, VU], or the IL-th through IU-th   
    eigenvalues.   

    To avoid overflow, the matrix must be scaled so that its   
    largest element is no greater than overflow**(1/2) *   
    underflow**(1/4) in absolute value, and for greatest   
    accuracy, it should not be much smaller than that.   

    See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal   
    Matrix", Report CS41, Computer Science Dept., Stanford   
    University, July 21, 1966.   

    Arguments   
    =========   

    RANGE   (input) CHARACTER   
            = 'A': ("All")   all eigenvalues will be found.   
            = 'V': ("Value") all eigenvalues in the half-open interval   
                             (VL, VU] will be found.   
            = 'I': ("Index") the IL-th through IU-th eigenvalues (of the 
  
                             entire matrix) will be found.   

    ORDER   (input) CHARACTER   
            = 'B': ("By Block") the eigenvalues will be grouped by   
                                split-off block (see IBLOCK, ISPLIT) and 
  
                                ordered from smallest to largest within   
                                the block.   
            = 'E': ("Entire matrix")   
                                the eigenvalues for the entire matrix   
                                will be ordered from smallest to   
                                largest.   

    N       (input) INTEGER   
            The order of the tridiagonal matrix T.  N >= 0.   

    VL      (input) REAL   
    VU      (input) REAL   
            If RANGE='V', the lower and upper bounds of the interval to   
            be searched for eigenvalues.  Eigenvalues less than or equal 
  
            to VL, or greater than VU, will not be returned.  VL < VU.   
            Not referenced if RANGE = 'A' or 'I'.   

    IL      (input) INTEGER   
    IU      (input) INTEGER   
            If RANGE='I', the indices (in ascending order) of the   
            smallest and largest eigenvalues to be returned.   
            1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0.   
            Not referenced if RANGE = 'A' or 'V'.   

    ABSTOL  (input) REAL   
            The absolute tolerance for the eigenvalues.  An eigenvalue   
            (or cluster) is considered to be located if it has been   
            determined to lie in an interval whose width is ABSTOL or   
            less.  If ABSTOL is less than or equal to zero, then ULP*|T| 
  
            will be used, where |T| means the 1-norm of T.   

            Eigenvalues will be computed most accurately when ABSTOL is   
            set to twice the underflow threshold 2*SLAMCH('S'), not zero. 
  

    D       (input) REAL array, dimension (N)   
            The n diagonal elements of the tridiagonal matrix T.   

    E       (input) REAL array, dimension (N-1)   
            The (n-1) off-diagonal elements of the tridiagonal matrix T. 
  

    M       (output) INTEGER   
            The actual number of eigenvalues found. 0 <= M <= N.   
            (See also the description of INFO=2,3.)   

    NSPLIT  (output) INTEGER   
            The number of diagonal blocks in the matrix T.   
            1 <= NSPLIT <= N.   

    W       (output) REAL array, dimension (N)   
            On exit, the first M elements of W will contain the   
            eigenvalues.  (SSTEBZ may use the remaining N-M elements as   
            workspace.)   

//.........这里部分代码省略.........

struct dinode *inodeFromINum(uint inum) {
	uint blockNum = IBLOCK(inum);
	void *blockPtr = blockPtrFromBNum(blockNum);
	return (struct dinode *) blockPtr + (inum % IPB);
}