336 lines
10 KiB
C
336 lines
10 KiB
C
/* This file manages the inode table. There are procedures to allocate and
|
|
* deallocate inodes, acquire, erase, and release them, and read and write
|
|
* them from the disk.
|
|
*
|
|
* The entry points into this file are
|
|
* get_inode: search inode table for a given inode; if not there,
|
|
* read it
|
|
* put_inode: indicate that an inode is no longer needed in memory
|
|
* alloc_inode: allocate a new, unused inode
|
|
* wipe_inode: erase some fields of a newly allocated inode
|
|
* free_inode: mark an inode as available for a new file
|
|
* update_times: update atime, ctime, and mtime
|
|
* find_inode: retrieve pointer to inode in inode cache
|
|
*
|
|
*/
|
|
|
|
#include "fs.h"
|
|
#include "buf.h"
|
|
#include "inode.h"
|
|
#include <minix/vfsif.h>
|
|
|
|
FORWARD _PROTOTYPE( void addhash_inode, (struct inode * const node) );
|
|
FORWARD _PROTOTYPE( void unhash_inode, (struct inode * const node) );
|
|
|
|
|
|
/*===========================================================================*
|
|
* fs_putnode *
|
|
*===========================================================================*/
|
|
PUBLIC int fs_putnode(message *fs_m_in, message *fs_m_out)
|
|
{
|
|
/* Find the inode specified by the request message and decrease its counter.*/
|
|
|
|
struct inode *rip;
|
|
int count;
|
|
dev_t dev;
|
|
ino_t inum;
|
|
|
|
rip = find_inode( (ino_t) fs_m_in->REQ_INODE_NR);
|
|
|
|
if(!rip) {
|
|
printf("%s:%d put_inode: inode #%ld dev: %d not found\n", __FILE__,
|
|
__LINE__, fs_m_in->REQ_INODE_NR, (dev_t) fs_m_in->REQ_DEV);
|
|
panic("fs_putnode failed");
|
|
}
|
|
|
|
count = fs_m_in->REQ_COUNT;
|
|
if (count <= 0) {
|
|
printf("%s:%d put_inode: bad value for count: %d\n", __FILE__,
|
|
__LINE__, count);
|
|
panic("fs_putnode failed");
|
|
} else if(count > rip->i_count) {
|
|
printf("%s:%d put_inode: count too high: %d > %d\n", __FILE__,
|
|
__LINE__, count, rip->i_count);
|
|
panic("fs_putnode failed");
|
|
}
|
|
|
|
/* Decrease reference counter, but keep one reference; it will be consumed by
|
|
* put_inode(). */
|
|
rip->i_count -= count - 1;
|
|
dev = rip->i_dev;
|
|
inum = rip->i_num;
|
|
put_inode(rip);
|
|
if (rip->i_count == 0) put_block(dev, inum);
|
|
return(OK);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* init_inode_cache *
|
|
*===========================================================================*/
|
|
PUBLIC void init_inode_cache()
|
|
{
|
|
struct inode *rip;
|
|
struct inodelist *rlp;
|
|
|
|
/* init free/unused list */
|
|
TAILQ_INIT(&unused_inodes);
|
|
|
|
/* init hash lists */
|
|
for (rlp = &hash_inodes[0]; rlp < &hash_inodes[INODE_HASH_SIZE]; ++rlp)
|
|
LIST_INIT(rlp);
|
|
|
|
/* add free inodes to unused/free list */
|
|
for (rip = &inode[0]; rip < &inode[NR_INODES]; ++rip) {
|
|
rip->i_num = NO_ENTRY;
|
|
TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
|
|
}
|
|
|
|
/* Reserve the first inode (bit 0) to prevent it from being allocated later*/
|
|
if (alloc_bit() != NO_BIT) printf("PFS could not reserve NO_BIT\n");
|
|
busy = 0; /* This bit does not make the server 'in use/busy'. */
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* addhash_inode *
|
|
*===========================================================================*/
|
|
PRIVATE void addhash_inode(struct inode * const node)
|
|
{
|
|
int hashi = (int) (node->i_num & INODE_HASH_MASK);
|
|
|
|
/* insert into hash table */
|
|
LIST_INSERT_HEAD(&hash_inodes[hashi], node, i_hash);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* unhash_inode *
|
|
*===========================================================================*/
|
|
PRIVATE void unhash_inode(struct inode * const node)
|
|
{
|
|
/* remove from hash table */
|
|
LIST_REMOVE(node, i_hash);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* get_inode *
|
|
*===========================================================================*/
|
|
PUBLIC struct inode *get_inode(
|
|
dev_t dev, /* device on which inode resides */
|
|
ino_t numb /* inode number */
|
|
)
|
|
{
|
|
/* Find the inode in the hash table. If it is not there, get a free inode
|
|
* load it from the disk if it's necessary and put on the hash list
|
|
*/
|
|
register struct inode *rip;
|
|
int hashi;
|
|
|
|
hashi = (int) (numb & INODE_HASH_MASK);
|
|
|
|
/* Search inode in the hash table */
|
|
LIST_FOREACH(rip, &hash_inodes[hashi], i_hash) {
|
|
if (rip->i_num == numb && rip->i_dev == dev) {
|
|
/* If unused, remove it from the unused/free list */
|
|
if (rip->i_count == 0) {
|
|
TAILQ_REMOVE(&unused_inodes, rip, i_unused);
|
|
}
|
|
++rip->i_count;
|
|
|
|
return(rip);
|
|
}
|
|
}
|
|
|
|
/* Inode is not on the hash, get a free one */
|
|
if (TAILQ_EMPTY(&unused_inodes)) {
|
|
err_code = ENFILE;
|
|
return(NULL);
|
|
}
|
|
rip = TAILQ_FIRST(&unused_inodes);
|
|
|
|
/* If not free unhash it */
|
|
if (rip->i_num != NO_ENTRY) unhash_inode(rip);
|
|
|
|
/* Inode is not unused any more */
|
|
TAILQ_REMOVE(&unused_inodes, rip, i_unused);
|
|
|
|
/* Load the inode. */
|
|
rip->i_dev = dev;
|
|
rip->i_num = numb;
|
|
rip->i_count = 1;
|
|
rip->i_update = 0; /* all the times are initially up-to-date */
|
|
|
|
/* Add to hash */
|
|
addhash_inode(rip);
|
|
|
|
|
|
return(rip);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* find_inode *
|
|
*===========================================================================*/
|
|
PUBLIC struct inode *find_inode(numb)
|
|
ino_t numb; /* inode number */
|
|
{
|
|
/* Find the inode specified by the inode and device number.
|
|
*/
|
|
struct inode *rip;
|
|
int hashi;
|
|
|
|
hashi = (int) (numb & INODE_HASH_MASK);
|
|
|
|
/* Search inode in the hash table */
|
|
LIST_FOREACH(rip, &hash_inodes[hashi], i_hash) {
|
|
if (rip->i_count > 0 && rip->i_num == numb) {
|
|
return(rip);
|
|
}
|
|
}
|
|
|
|
return(NULL);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* put_inode *
|
|
*===========================================================================*/
|
|
PUBLIC void put_inode(rip)
|
|
struct inode *rip; /* pointer to inode to be released */
|
|
{
|
|
/* The caller is no longer using this inode. If no one else is using it either
|
|
* write it back to the disk immediately. If it has no links, truncate it and
|
|
* return it to the pool of available inodes.
|
|
*/
|
|
|
|
if (rip == NULL) return; /* checking here is easier than in caller */
|
|
|
|
if (rip->i_count < 1)
|
|
panic("put_inode: i_count already below 1: %d", rip->i_count);
|
|
|
|
if (--rip->i_count == 0) { /* i_count == 0 means no one is using it now */
|
|
if (rip->i_nlinks == NO_LINK) { /* Are there links to this file? */
|
|
/* no links, free the inode. */
|
|
truncate_inode(rip, 0); /* return all the disk blocks */
|
|
rip->i_mode = I_NOT_ALLOC; /* clear I_TYPE field */
|
|
free_inode(rip);
|
|
} else {
|
|
truncate_inode(rip, (off_t) 0);
|
|
}
|
|
|
|
if (rip->i_nlinks == NO_LINK) {
|
|
/* free, put at the front of the LRU list */
|
|
unhash_inode(rip);
|
|
rip->i_num = NO_ENTRY;
|
|
rip->i_dev = NO_DEV;
|
|
rip->i_rdev = NO_DEV;
|
|
TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
|
|
} else {
|
|
/* unused, put at the back of the LRU (cache it) */
|
|
TAILQ_INSERT_TAIL(&unused_inodes, rip, i_unused);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* alloc_inode *
|
|
*===========================================================================*/
|
|
PUBLIC struct inode *alloc_inode(dev_t dev, mode_t bits)
|
|
{
|
|
/* Allocate a free inode on 'dev', and return a pointer to it. */
|
|
|
|
register struct inode *rip;
|
|
bit_t b;
|
|
ino_t i_num;
|
|
|
|
b = alloc_bit();
|
|
if (b == NO_BIT) {
|
|
err_code = ENOSPC;
|
|
printf("PipeFS is out of inodes\n");
|
|
return(NULL);
|
|
}
|
|
i_num = (ino_t) b;
|
|
|
|
|
|
/* Try to acquire a slot in the inode table. */
|
|
if ((rip = get_inode(dev, i_num)) == NULL) {
|
|
/* No inode table slots available. Free the inode if just allocated.*/
|
|
if (dev == NO_DEV) free_bit(b);
|
|
} else {
|
|
/* An inode slot is available. */
|
|
|
|
rip->i_mode = bits; /* set up RWX bits */
|
|
rip->i_nlinks = NO_LINK; /* initial no links */
|
|
rip->i_uid = caller_uid; /* file's uid is owner's */
|
|
rip->i_gid = caller_gid; /* ditto group id */
|
|
|
|
/* Fields not cleared already are cleared in wipe_inode(). They have
|
|
* been put there because truncate() needs to clear the same fields if
|
|
* the file happens to be open while being truncated. It saves space
|
|
* not to repeat the code twice.
|
|
*/
|
|
wipe_inode(rip);
|
|
}
|
|
|
|
return(rip);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* wipe_inode *
|
|
*===========================================================================*/
|
|
PUBLIC void wipe_inode(rip)
|
|
struct inode *rip; /* the inode to be erased */
|
|
{
|
|
/* Erase some fields in the inode. This function is called from alloc_inode()
|
|
* when a new inode is to be allocated, and from truncate(), when an existing
|
|
* inode is to be truncated.
|
|
*/
|
|
|
|
rip->i_size = 0;
|
|
rip->i_update = ATIME | CTIME | MTIME; /* update all times later */
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* free_inode *
|
|
*===========================================================================*/
|
|
PUBLIC void free_inode(rip)
|
|
struct inode *rip;
|
|
{
|
|
/* Return an inode to the pool of unallocated inodes. */
|
|
|
|
bit_t b;
|
|
|
|
if (rip->i_num <= (ino_t) 0 || rip->i_num >= (ino_t) NR_INODES) return;
|
|
b = (bit_t) rip->i_num;
|
|
free_bit(b);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* update_times *
|
|
*===========================================================================*/
|
|
PUBLIC void update_times(rip)
|
|
struct inode *rip; /* pointer to inode to be read/written */
|
|
{
|
|
/* Various system calls are required by the standard to update atime, ctime,
|
|
* or mtime. Since updating a time requires sending a message to the clock
|
|
* task--an expensive business--the times are marked for update by setting
|
|
* bits in i_update. When a stat, fstat, or sync is done, or an inode is
|
|
* released, update_times() may be called to actually fill in the times.
|
|
*/
|
|
|
|
time_t cur_time;
|
|
|
|
cur_time = clock_time();
|
|
if (rip->i_update & ATIME) rip->i_atime = cur_time;
|
|
if (rip->i_update & CTIME) rip->i_ctime = cur_time;
|
|
if (rip->i_update & MTIME) rip->i_mtime = cur_time;
|
|
rip->i_update = 0; /* they are all up-to-date now */
|
|
}
|
|
|