inode.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "fs.h"
//member functions for Inode, Itable class
void Inode_init(struct Inode *in){
   in->ino=-1;
   //in->num_blk=0; // 0 blocks assigned yet
}
void ITable_make_inode(int ino, int blkno){
// make new inode in disk and copy it in itable
   struct Ext2Inode * inode;
   struct Inode *in;
   inode=Ext2Inode_make_inode(ino, blkno);
   in = ITable_get_free_inode();
   in->ino=ino;
   in->inode=inode;
}
   
void Inode_alloc_block(struct Inode *in, int blk_no){
// assign a block (whose block number is blk_no) to this inode
   Ext2Inode_alloc_block(in->inode, blk_no);
}

struct DirBlock *Inode_get_block(struct Inode *in, int b){
// return b-th block of file with inode "in"
   // block num
   int  bno = in->inode->i_block[b];
   return (struct DirBlock *)FBTable_get_block(bno);
}

void ITable_init(){
   int i;
   for(i=0;i<MAX_INODE_ITABLE;i++)
      Inode_init(&(itable.arr[i]));
}

struct Inode * ITable_get_free_inode(){
   int i;
   for(i=0;i<MAX_INODE_ITABLE;i++)
      if (itable.arr[i].ino==-1)
	     return &(itable.arr[i]);
}
struct Inode * ITable_get_inode(int ino){
// this inode is not in the system ITable. get it
   struct Ext2Inode * inode;
   struct Inode *in;
   inode = Ext2Inode_get_inode(ino);
   in = ITable_get_free_inode();
   in->ino = ino;
   in->inode = inode;
   return in;
}

struct Inode *ITable_find_loc(int ino){
// the location of inode in inode table that has inode num = ino
   int i;
   for(i=0;i<MAX_INODE_ITABLE;i++)
      if (itable.arr[i].ino==ino)
	     return &(itable.arr[i]);
   // if we couldn't find, get it
   return ITable_get_inode(ino);
}



struct Inode *find_inode_for_file(struct Inode *currdir, char *f){
// return the inode for file f which belongs to currdir.
   int ino = find_ino_for_file_in_dir(f, currdir); // get ino
   struct Inode *in = ITable_find_loc(ino);
   printk("inode for %s is %d\n", f, ino);
   return in;
}

struct Inode *ITable_compute_inode(char *path){
// bring in the inode of file "path" and return the pointer
// suppose path was /aa/bb
   char dir[EXT2_NAME_LEN+1], *temp;
   struct Inode *curr_inode;
   int leaf; // we don't use this here

   leaf = get_next_fname(path,dir);
   // following should changed later so that we use current->root, current->pwd
   if (dir[0]=='/' && strlen(dir)==1){
      curr_inode = root; // root dir indoe
   } 
   else panic("only absolute path supported for now\n");
   temp = path; // temp is /aa/bb
   for(;;){
      temp=move_to_remaining_path(temp); // temp is aa/bb, bb, NULL 
	  if (temp==0) return curr_inode; // return inode of /aa/bb
	  leaf=get_next_fname(temp, dir); // dir is aa, bb
	  curr_inode = find_inode_for_file(curr_inode, dir); 
	                           // curr_inode is /aa, /aa/bb
   }
}

struct Inode *ITable_compute_inode_for_last_directory(char *path, char *leaf_name){
// bring in the inode of last dir in "path" and return the pointer, and at the
// same time return the leaf file name in leaf_name
// suppose path was /aa/bb/cc, then we return inode of /aa/bb, and cc in
// leaf_name
   char dir[EXT2_NAME_LEN+1], *temp;
   struct Inode *curr_inode;
   int leaf;
   printk("comp inode for last dir. path is %s :", path);
   leaf = get_next_fname(path, dir);
   printk("next fname is %s : ", dir);
   // following should changed later so that we use current->root, current->pwd
   if (dir[0]=='/' && strlen(dir)==1){
      curr_inode = &(itable.arr[2]); // root dir indoe
   } 
   else panic("only absolute path supported for now\n");
   temp = path; // temp is /aa/bb/cc
   for(;;){
      printk("curr inode no is %d : ",curr_inode->ino);
      temp=move_to_remaining_path(temp); // temp is aa/bb/cc, bb/cc, cc
	  if (temp==0) panic("we reached end of path\n"); //this shouldn't happen
	  leaf = get_next_fname(temp, dir); // dir is aa, bb, cc
	  if (leaf==1){ // we reached the end of the path. leaf is 0,0,1
	     // leaf file name
		 strcpy(leaf_name, dir);
		 printk("returning. leaf_name %s last dir ino %d\n",leaf_name,curr_inode->ino);
	     return curr_inode; // return the last directory
	  }
	  curr_inode = find_inode_for_file(curr_inode, dir); 
	                           // curr_inode is /aa, /aa/bb
   }
}