Linux中文件系统truncate.c源码分析

static void free_ind(int dev,int block)

struct buffer_head * bh;unsigned short * p;int i;if (!block)    return;if ((bh=bread(dev,block))) {

for (i=0;i<512;i++,p++)    if (*p)        free_block(dev,*p);brelse(bh);free_block(dev,block);

static void free_dind(int dev,int block)

struct buffer_head * bh;unsigned short * p;int i;if (!block)    return;

if ((bh=bread(dev,block))) {    p = (unsigned short *) bh->b_data;    for (i=0;i<512;i++,p++)        if (*p)            free_ind(dev,*p);    brelse(bh);}free_block(dev,block);

void truncate(struct m_inode * inode)

int i;if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))    return;

for (i=0;i<7;i++)    if (inode->i_zone[i]) {        free_block(inode->i_dev,inode->i_zone[i]);        inode->i_zone[i]=0;    }

free_ind(inode->i_dev,inode->i_zone[7]);free_dind(inode->i_dev,inode->i_zone[8]);

inode->i_zone[7] = inode->i_zone[8] = 0;inode->i_size = 0;inode->i_dirt = 1;inode->i_mtime = inode->i_ctime = CURRENT_TIME;