426 lines
14 KiB
C
426 lines
14 KiB
C
/* This file manages the inode table. There are procedures to allocate and
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* deallocate inodes, acquire, erase, and release them, and read and write
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* them from the disk.
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*
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* The entry points into this file are
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* get_inode: search inode table for a given inode; if not there,
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* read it
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* put_inode: indicate that an inode is no longer needed in memory
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* update_times: update atime, ctime, and mtime
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* rw_inode: read a disk block and extract an inode, or corresp. write
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* dup_inode: indicate that someone else is using an inode table entry
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* find_inode: retrieve pointer to inode in inode cache
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*
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* Created (MFS based):
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* February 2010 (Evgeniy Ivanov)
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*/
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#include "fs.h"
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#include <string.h>
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#include "buf.h"
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#include "inode.h"
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#include "super.h"
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#include <minix/vfsif.h>
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FORWARD _PROTOTYPE( void icopy, (struct inode *rip, d_inode *dip,
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int direction, int norm));
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FORWARD _PROTOTYPE( void addhash_inode, (struct inode *node) );
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FORWARD _PROTOTYPE( void unhash_inode, (struct inode *node) );
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/*===========================================================================*
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* fs_putnode *
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*===========================================================================*/
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PUBLIC int fs_putnode(void)
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{
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/* Find the inode specified by the request message and decrease its counter.*/
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struct inode *rip;
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int count;
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rip = find_inode(fs_dev, (ino_t) fs_m_in.REQ_INODE_NR);
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if (!rip) {
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printf("%s:%d put_inode: inode #%lu dev: %d not found\n", __FILE__,
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__LINE__, (ino_t) fs_m_in.REQ_INODE_NR, fs_dev);
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panic("fs_putnode failed");
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}
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count = fs_m_in.REQ_COUNT;
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if (count <= 0) {
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printf("%s:%d put_inode: bad value for count: %d\n", __FILE__,
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__LINE__, count);
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panic("fs_putnode failed");
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} else if (count > rip->i_count) {
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printf("%s:%d put_inode: count too high: %d > %d\n", __FILE__,
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__LINE__, count, rip->i_count);
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panic("fs_putnode failed");
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}
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/* Decrease reference counter, but keep one reference;
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* it will be consumed by put_inode().
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*/
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rip->i_count -= count - 1;
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put_inode(rip);
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return(OK);
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}
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/*===========================================================================*
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* init_inode_cache *
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*===========================================================================*/
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PUBLIC void init_inode_cache()
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{
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struct inode *rip;
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struct inodelist *rlp;
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inode_cache_hit = 0;
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inode_cache_miss = 0;
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/* init free/unused list */
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TAILQ_INIT(&unused_inodes);
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/* init hash lists */
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for (rlp = &hash_inodes[0]; rlp < &hash_inodes[INODE_HASH_SIZE]; ++rlp)
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LIST_INIT(rlp);
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/* add free inodes to unused/free list */
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for (rip = &inode[0]; rip < &inode[NR_INODES]; ++rip) {
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rip->i_num = NO_ENTRY;
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TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
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}
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}
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/*===========================================================================*
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* addhash_inode *
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*===========================================================================*/
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PRIVATE void addhash_inode(struct inode *node)
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{
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int hashi = node->i_num & INODE_HASH_MASK;
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/* insert into hash table */
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LIST_INSERT_HEAD(&hash_inodes[hashi], node, i_hash);
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}
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/*===========================================================================*
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* unhash_inode *
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*===========================================================================*/
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PRIVATE void unhash_inode(struct inode *node)
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{
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/* remove from hash table */
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LIST_REMOVE(node, i_hash);
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}
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/*===========================================================================*
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* get_inode *
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*===========================================================================*/
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PUBLIC struct inode *get_inode(
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dev_t dev, /* device on which inode resides */
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ino_t numb /* inode number (ANSI: may not be unshort) */
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)
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{
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/* Find the inode in the hash table. If it is not there, get a free inode
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* load it from the disk if it's necessary and put on the hash list
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*/
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register struct inode *rip;
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int hashi;
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int i;
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hashi = (int) numb & INODE_HASH_MASK;
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/* Search inode in the hash table */
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LIST_FOREACH(rip, &hash_inodes[hashi], i_hash) {
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if (rip->i_num == numb && rip->i_dev == dev) {
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/* If unused, remove it from the unused/free list */
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if (rip->i_count == 0) {
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inode_cache_hit++;
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TAILQ_REMOVE(&unused_inodes, rip, i_unused);
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}
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++rip->i_count;
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return(rip);
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}
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}
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inode_cache_miss++;
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/* Inode is not on the hash, get a free one */
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if (TAILQ_EMPTY(&unused_inodes)) {
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err_code = ENFILE;
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return(NULL);
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}
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rip = TAILQ_FIRST(&unused_inodes);
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/* If not free unhash it */
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if (rip->i_num != NO_ENTRY)
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unhash_inode(rip);
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/* Inode is not unused any more */
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TAILQ_REMOVE(&unused_inodes, rip, i_unused);
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/* Load the inode. */
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rip->i_dev = dev;
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rip->i_num = numb;
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rip->i_count = 1;
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if (dev != NO_DEV)
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rw_inode(rip, READING); /* get inode from disk */
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rip->i_update = 0; /* all the times are initially up-to-date */
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rip->i_last_dpos = 0; /* no dentries searched for yet */
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rip->i_bsearch = NO_BLOCK;
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rip->i_last_pos_bl_alloc = 0;
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rip->i_last_dentry_size = 0;
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rip->i_mountpoint= FALSE;
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rip->i_preallocation = opt.use_prealloc;
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rip->i_prealloc_count = rip->i_prealloc_index = 0;
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for (i = 0; i < EXT2_PREALLOC_BLOCKS; i++) {
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if (rip->i_prealloc_blocks[i] != NO_BLOCK) {
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/* Actually this should never happen */
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free_block(rip->i_sp, rip->i_prealloc_blocks[i]);
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rip->i_prealloc_blocks[i] = NO_BLOCK;
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ext2_debug("Warning: Unexpected preallocated block.");
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}
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}
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/* Add to hash */
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addhash_inode(rip);
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return(rip);
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}
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/*===========================================================================*
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* find_inode *
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*===========================================================================*/
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PUBLIC struct inode *find_inode(
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dev_t dev, /* device on which inode resides */
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ino_t numb /* inode number (ANSI: may not be unshort) */
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)
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{
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/* Find the inode specified by the inode and device number. */
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struct inode *rip;
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int hashi;
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hashi = (int) numb & INODE_HASH_MASK;
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/* Search inode in the hash table */
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LIST_FOREACH(rip, &hash_inodes[hashi], i_hash) {
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if (rip->i_count > 0 && rip->i_num == numb && rip->i_dev == dev) {
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return(rip);
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}
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}
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return(NULL);
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}
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/*===========================================================================*
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* put_inode *
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*===========================================================================*/
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PUBLIC void put_inode(
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register struct inode *rip /* pointer to inode to be released */
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)
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{
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/* The caller is no longer using this inode. If no one else is using it either
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* write it back to the disk immediately. If it has no links, truncate it and
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* return it to the pool of available inodes.
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*/
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if (rip == NULL)
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return; /* checking here is easier than in caller */
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if (rip->i_count < 1)
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panic("put_inode: i_count already below 1", rip->i_count);
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if (--rip->i_count == 0) { /* i_count == 0 means no one is using it now */
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if (rip->i_links_count == NO_LINK) {
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/* i_nlinks == NO_LINK means free the inode. */
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/* return all the disk blocks */
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/* Ignore errors by truncate_inode in case inode is a block
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* special or character special file.
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*/
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(void) truncate_inode(rip, (off_t) 0);
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/* free inode clears I_TYPE field, since it's used there */
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rip->i_dirt = DIRTY;
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free_inode(rip);
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}
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rip->i_mountpoint = FALSE;
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if (rip->i_dirt == DIRTY) rw_inode(rip, WRITING);
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discard_preallocated_blocks(rip); /* Return blocks to the filesystem */
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if (rip->i_links_count == NO_LINK) {
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/* free, put at the front of the LRU list */
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unhash_inode(rip);
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rip->i_num = NO_ENTRY;
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TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
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} else {
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/* unused, put at the back of the LRU (cache it) */
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TAILQ_INSERT_TAIL(&unused_inodes, rip, i_unused);
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}
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}
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}
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/*===========================================================================*
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* update_times *
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*===========================================================================*/
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PUBLIC void update_times(
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register struct inode *rip /* pointer to inode to be read/written */
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)
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{
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/* Various system calls are required by the standard to update atime, ctime,
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* or mtime. Since updating a time requires sending a message to the clock
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* task--an expensive business--the times are marked for update by setting
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* bits in i_update. When a stat, fstat, or sync is done, or an inode is
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* released, update_times() may be called to actually fill in the times.
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*/
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time_t cur_time;
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struct super_block *sp;
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sp = rip->i_sp; /* get pointer to super block. */
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if (sp->s_rd_only)
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return; /* no updates for read-only file systems */
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cur_time = clock_time();
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if (rip->i_update & ATIME)
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rip->i_atime = cur_time;
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if (rip->i_update & CTIME)
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rip->i_ctime = cur_time;
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if (rip->i_update & MTIME)
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rip->i_mtime = cur_time;
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rip->i_update = 0; /* they are all up-to-date now */
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}
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/*===========================================================================*
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* rw_inode *
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*===========================================================================*/
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PUBLIC void rw_inode(
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register struct inode *rip, /* pointer to inode to be read/written */
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int rw_flag /* READING or WRITING */
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)
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{
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/* An entry in the inode table is to be copied to or from the disk. */
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register struct buf *bp;
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register struct super_block *sp;
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register struct group_desc *gd;
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register d_inode *dip;
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u32_t block_group_number;
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block_t b, offset;
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/* Get the block where the inode resides. */
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sp = get_super(rip->i_dev); /* get pointer to super block */
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rip->i_sp = sp; /* inode must contain super block pointer */
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block_group_number = (rip->i_num - 1) / sp->s_inodes_per_group;
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gd = get_group_desc(block_group_number);
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if (gd == NULL)
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panic("can't get group_desc to read/write inode");
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offset = ((rip->i_num - 1) % sp->s_inodes_per_group) * EXT2_INODE_SIZE(sp);
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/* offset requires shifting, since each block contains several inodes,
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* e.g. inode 2 is stored in bklock 0.
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*/
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b = (block_t) gd->inode_table + (offset >> sp->s_blocksize_bits);
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bp = get_block(rip->i_dev, b, NORMAL);
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offset &= (sp->s_block_size - 1);
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dip = (d_inode*) (bp->b_data + offset);
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/* Do the read or write. */
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if (rw_flag == WRITING) {
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if (rip->i_update)
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update_times(rip); /* times need updating */
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if (sp->s_rd_only == FALSE)
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bp->b_dirt = DIRTY;
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}
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icopy(rip, dip, rw_flag, TRUE);
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put_block(bp, INODE_BLOCK);
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rip->i_dirt = CLEAN;
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}
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/*===========================================================================*
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* icopy *
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*===========================================================================*/
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PRIVATE void icopy(
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register struct inode *rip, /* pointer to the in-core inode struct */
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register d_inode *dip, /* pointer to the on-disk struct */
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int direction, /* READING (from disk) or WRITING (to disk) */
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int norm /* TRUE = do not swap bytes; FALSE = swap */
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)
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{
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int i;
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if (direction == READING) {
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/* Copy inode to the in-core table, swapping bytes if need be. */
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rip->i_mode = conv2(norm,dip->i_mode);
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rip->i_uid = conv2(norm,dip->i_uid);
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rip->i_size = conv4(norm,dip->i_size);
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rip->i_atime = conv4(norm,dip->i_atime);
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rip->i_ctime = conv4(norm,dip->i_ctime);
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rip->i_mtime = conv4(norm,dip->i_mtime);
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rip->i_dtime = conv4(norm,dip->i_dtime);
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rip->i_gid = conv2(norm,dip->i_gid);
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rip->i_links_count = conv2(norm,dip->i_links_count);
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rip->i_blocks = conv4(norm,dip->i_blocks);
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rip->i_flags = conv4(norm,dip->i_flags);
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/* Minix doesn't touch osd1 and osd2 either, so just copy. */
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memcpy(&rip->osd1, &dip->osd1, sizeof(rip->osd1));
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for (i = 0; i < EXT2_N_BLOCKS; i++)
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rip->i_block[i] = conv4(norm, dip->i_block[i]);
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rip->i_generation = conv4(norm,dip->i_generation);
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rip->i_file_acl = conv4(norm,dip->i_file_acl);
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rip->i_dir_acl = conv4(norm,dip->i_dir_acl);
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rip->i_faddr = conv4(norm,dip->i_faddr);
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memcpy(&rip->osd2, &dip->osd2, sizeof(rip->osd2));
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} else {
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/* Copying inode to disk from the in-core table. */
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dip->i_mode = conv2(norm,rip->i_mode);
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dip->i_uid = conv2(norm,rip->i_uid);
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dip->i_size = conv4(norm,rip->i_size);
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dip->i_atime = conv4(norm,rip->i_atime);
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dip->i_ctime = conv4(norm,rip->i_ctime);
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dip->i_mtime = conv4(norm,rip->i_mtime);
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dip->i_dtime = conv4(norm,rip->i_dtime);
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dip->i_gid = conv2(norm,rip->i_gid);
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dip->i_links_count = conv2(norm,rip->i_links_count);
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dip->i_blocks = conv4(norm,rip->i_blocks);
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dip->i_flags = conv4(norm,rip->i_flags);
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/* Minix doesn't touch osd1 and osd2 either, so just copy. */
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memcpy(&dip->osd1, &rip->osd1, sizeof(dip->osd1));
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for (i = 0; i < EXT2_N_BLOCKS; i++)
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dip->i_block[i] = conv4(norm, rip->i_block[i]);
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dip->i_generation = conv4(norm,rip->i_generation);
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dip->i_file_acl = conv4(norm,rip->i_file_acl);
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dip->i_dir_acl = conv4(norm,rip->i_dir_acl);
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dip->i_faddr = conv4(norm,rip->i_faddr);
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memcpy(&dip->osd2, &rip->osd2, sizeof(dip->osd2));
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}
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}
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/*===========================================================================*
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* dup_inode *
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*===========================================================================*/
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PUBLIC void dup_inode(
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struct inode *ip /* The inode to be duplicated. */
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)
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{
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/* This routine is a simplified form of get_inode() for the case where
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* the inode pointer is already known.
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*/
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ip->i_count++;
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}
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