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minix/servers/mfs/inode.c
David van Moolenbroek 5a370afc8e MFS put_inode issues (reported by Maurizio Lombardi)
2009-07-22 08:54:28 +00:00

561 lines
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/* 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
* rw_inode: read a disk block and extract an inode, or corresp. write
* old_icopy: copy to/from in-core inode struct and disk inode (V1.x)
* new_icopy: copy to/from in-core inode struct and disk inode (V2.x)
* dup_inode: indicate that someone else is using an inode table entry
*
* Updates:
* 2007-06-01: jfdsmit@gmail.com added i_zsearch initialization
*/
#include "fs.h"
#include "buf.h"
#include "inode.h"
#include "super.h"
#include <minix/vfsif.h>
FORWARD _PROTOTYPE( void old_icopy, (struct inode *rip, d1_inode *dip,
int direction, int norm));
FORWARD _PROTOTYPE( void new_icopy, (struct inode *rip, d2_inode *dip,
int direction, int norm));
/*===========================================================================*
* fs_putnode *
*===========================================================================*/
PUBLIC int fs_putnode()
{
/* Find the inode specified by the request message and decrease its counter.
*/
struct inode *rip;
int count;
/* Sanity check for the direct index */
if (fs_m_in.REQ_INODE_INDEX >= 0 &&
fs_m_in.REQ_INODE_INDEX < NR_INODES &&
inode[fs_m_in.REQ_INODE_INDEX].i_num == fs_m_in.REQ_INODE_NR) {
rip = &inode[fs_m_in.REQ_INODE_INDEX];
if(!rip) {
panic(__FILE__, "null rip", NO_NUM);
}
}
/* Otherwise find it */
else {
if(!(rip = find_inode(fs_dev, fs_m_in.REQ_INODE_NR))) {
printf("FSput_inode: inode #%d dev: %d not found, req_nr: %d\n",
fs_m_in.REQ_INODE_NR, fs_dev, req_nr);
}
}
if (!rip)
{
panic(__FILE__, "fs_putnode failed", NO_NUM);
}
count= fs_m_in.REQ_COUNT;
if (count <= 0)
{
printf("put_inode: bad value for count: %d\n", count);
panic(__FILE__, "fs_putnode failed", NO_NUM);
return EINVAL;
}
if (count > rip->i_count)
{
printf("put_inode: count too high: %d > %d\n", count, rip->i_count);
panic(__FILE__, "fs_putnode failed", NO_NUM);
return EINVAL;
}
rip->i_count -= count - 1;
put_inode(rip);
return OK;
}
/*===========================================================================*
* fs_getnode *
*===========================================================================*/
PUBLIC int fs_getnode()
{
/* Increase the inode's counter specified in the request message
*/
struct inode *rip;
/* Get the inode */
rip = get_inode(fs_dev, fs_m_in.REQ_INODE_NR);
if (!rip) {
printf("FS: inode #%d couldn't be found\n", fs_m_in.REQ_INODE_NR);
return EINVAL;
}
/* Transfer back the inode's details */
fs_m_out.m_source = rip->i_dev;
fs_m_out.RES_INODE_NR = rip->i_num;
fs_m_out.RES_MODE = rip->i_mode;
fs_m_out.RES_FILE_SIZE = rip->i_size;
fs_m_out.RES_DEV = (Dev_t) rip->i_zone[0];
fs_m_out.RES_UID = rip->i_uid;
fs_m_out.RES_GID = rip->i_gid;
return OK;
}
/*===========================================================================*
* init_inode_cache *
*===========================================================================*/
PUBLIC void init_inode_cache()
{
struct inode *rip;
struct inodelist *rlp;
inode_cache_hit = 0;
inode_cache_miss = 0;
/* 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 = 0;
TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
}
}
/*===========================================================================*
* addhash_inode *
*===========================================================================*/
PRIVATE int addhash_inode(struct inode *node)
{
int hashi = node->i_num & INODE_HASH_MASK;
/* insert into hash table */
LIST_INSERT_HEAD(&hash_inodes[hashi], node, i_hash);
return OK;
}
/*===========================================================================*
* unhash_inode *
*===========================================================================*/
PRIVATE int unhash_inode(struct inode *node)
{
/* remove from hash table */
LIST_REMOVE(node, i_hash);
return OK;
}
/*===========================================================================*
* get_inode *
*===========================================================================*/
PUBLIC struct inode *get_inode(dev, numb)
dev_t dev; /* device on which inode resides */
int numb; /* inode number (ANSI: may not be unshort) */
{
/* 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, *xp;
int hashi;
hashi = 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) {
inode_cache_hit++;
TAILQ_REMOVE(&unused_inodes, rip, i_unused);
}
++rip->i_count;
return rip;
}
}
inode_cache_miss++;
/* Inode is not on the hash, get a free one */
if (TAILQ_EMPTY(&unused_inodes)) {
err_code = ENFILE;
return NIL_INODE;
}
rip = TAILQ_FIRST(&unused_inodes);
/* If not free unhash it */
if (rip->i_num != 0)
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;
if (dev != NO_DEV) rw_inode(rip, READING); /* get inode from disk */
rip->i_update = 0; /* all the times are initially up-to-date */
rip->i_zsearch = NO_ZONE; /* no zones searched for yet */
if ((rip->i_mode & I_TYPE) == I_NAMED_PIPE)
rip->i_pipe = I_PIPE;
else
rip->i_pipe = NO_PIPE;
rip->i_mountpoint= FALSE;
/* Add to hash */
addhash_inode(rip);
return(rip);
}
/*===========================================================================*
* find_inode *
*===========================================================================*/
PUBLIC struct inode *find_inode(dev, numb)
dev_t dev; /* device on which inode resides */
int numb; /* inode number (ANSI: may not be unshort) */
{
/* Find the inode specified by the inode and device number.
*/
struct inode *rip;
int hashi;
hashi = 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 && rip->i_dev == dev) {
return rip;
}
}
return NIL_INODE;
}
/*===========================================================================*
* put_inode *
*===========================================================================*/
PUBLIC void put_inode(rip)
register 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 == NIL_INODE) return; /* checking here is easier than in caller */
if (rip->i_count < 1)
panic(__FILE__, "put_inode: i_count already below 1", rip->i_count);
if (--rip->i_count == 0) { /* i_count == 0 means no one is using it now */
if (rip->i_nlinks == 0) {
/* i_nlinks == 0 means free the inode. */
truncate_inode(rip, 0); /* return all the disk blocks */
rip->i_mode = I_NOT_ALLOC; /* clear I_TYPE field */
rip->i_dirt = DIRTY;
free_inode(rip->i_dev, rip->i_num);
}
else {
if (rip->i_pipe == I_PIPE) truncate_inode(rip, 0);
}
rip->i_mountpoint = FALSE;
if (rip->i_dirt == DIRTY) rw_inode(rip, WRITING);
if (rip->i_nlinks == 0) {
/* free, put at the front of the LRU list */
unhash_inode(rip);
rip->i_num = 0;
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;
register struct super_block *sp;
int major, minor, inumb;
bit_t b;
sp = get_super(dev); /* get pointer to super_block */
if (sp->s_rd_only) { /* can't allocate an inode on a read only device. */
err_code = EROFS;
return(NIL_INODE);
}
/* Acquire an inode from the bit map. */
b = alloc_bit(sp, IMAP, sp->s_isearch);
if (b == NO_BIT) {
err_code = ENFILE;
major = (int) (sp->s_dev >> MAJOR) & BYTE;
minor = (int) (sp->s_dev >> MINOR) & BYTE;
printf("Out of i-nodes on device %d/%d\n", major, minor);
return(NIL_INODE);
}
sp->s_isearch = b; /* next time start here */
inumb = (int) b; /* be careful not to pass unshort as param */
/* Try to acquire a slot in the inode table. */
if ((rip = get_inode(NO_DEV, inumb)) == NIL_INODE) {
/* No inode table slots available. Free the inode just allocated. */
free_bit(sp, IMAP, b);
} else {
/* An inode slot is available. Put the inode just allocated into it. */
rip->i_mode = bits; /* set up RWX bits */
rip->i_nlinks = 0; /* initial no links */
rip->i_uid = caller_uid; /* file's uid is owner's */
rip->i_gid = caller_gid; /* ditto group id */
rip->i_dev = dev; /* mark which device it is on */
rip->i_ndzones = sp->s_ndzones; /* number of direct zones */
rip->i_nindirs = sp->s_nindirs; /* number of indirect zones per blk*/
rip->i_sp = sp; /* pointer to super block */
/* 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)
register 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.
*/
register int i;
rip->i_size = 0;
rip->i_update = ATIME | CTIME | MTIME; /* update all times later */
rip->i_dirt = DIRTY;
for (i = 0; i < V2_NR_TZONES; i++) rip->i_zone[i] = NO_ZONE;
}
/*===========================================================================*
* free_inode *
*===========================================================================*/
PUBLIC void free_inode(dev, inumb)
dev_t dev; /* on which device is the inode */
ino_t inumb; /* number of inode to be freed */
{
/* Return an inode to the pool of unallocated inodes. */
register struct super_block *sp;
bit_t b;
/* Locate the appropriate super_block. */
sp = get_super(dev);
if (inumb <= 0 || inumb > sp->s_ninodes) return;
b = inumb;
free_bit(sp, IMAP, b);
if (b < sp->s_isearch) sp->s_isearch = b;
}
/*===========================================================================*
* update_times *
*===========================================================================*/
PUBLIC void update_times(rip)
register 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;
struct super_block *sp;
sp = rip->i_sp; /* get pointer to super block. */
if (sp->s_rd_only) return; /* no updates for read-only file systems */
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 */
}
/*===========================================================================*
* rw_inode *
*===========================================================================*/
PUBLIC void rw_inode(rip, rw_flag)
register struct inode *rip; /* pointer to inode to be read/written */
int rw_flag; /* READING or WRITING */
{
/* An entry in the inode table is to be copied to or from the disk. */
register struct buf *bp;
register struct super_block *sp;
d1_inode *dip;
d2_inode *dip2;
block_t b, offset;
/* Get the block where the inode resides. */
sp = get_super(rip->i_dev); /* get pointer to super block */
rip->i_sp = sp; /* inode must contain super block pointer */
offset = sp->s_imap_blocks + sp->s_zmap_blocks + 2;
b = (block_t) (rip->i_num - 1)/sp->s_inodes_per_block + offset;
bp = get_block(rip->i_dev, b, NORMAL);
dip = bp->b_v1_ino + (rip->i_num - 1) % V1_INODES_PER_BLOCK;
dip2 = bp->b_v2_ino + (rip->i_num - 1) %
V2_INODES_PER_BLOCK(sp->s_block_size);
/* Do the read or write. */
if (rw_flag == WRITING) {
if (rip->i_update) update_times(rip); /* times need updating */
if (sp->s_rd_only == FALSE) bp->b_dirt = DIRTY;
}
/* Copy the inode from the disk block to the in-core table or vice versa.
* If the fourth parameter below is FALSE, the bytes are swapped.
*/
if (sp->s_version == V1)
old_icopy(rip, dip, rw_flag, sp->s_native);
else
new_icopy(rip, dip2, rw_flag, sp->s_native);
put_block(bp, INODE_BLOCK);
rip->i_dirt = CLEAN;
}
/*===========================================================================*
* old_icopy *
*===========================================================================*/
PRIVATE void old_icopy(rip, dip, direction, norm)
register struct inode *rip; /* pointer to the in-core inode struct */
register d1_inode *dip; /* pointer to the d1_inode inode struct */
int direction; /* READING (from disk) or WRITING (to disk) */
int norm; /* TRUE = do not swap bytes; FALSE = swap */
{
/* The V1.x IBM disk, the V1.x 68000 disk, and the V2 disk (same for IBM and
* 68000) all have different inode layouts. When an inode is read or written
* this routine handles the conversions so that the information in the inode
* table is independent of the disk structure from which the inode came.
* The old_icopy routine copies to and from V1 disks.
*/
int i;
if (direction == READING) {
/* Copy V1.x inode to the in-core table, swapping bytes if need be. */
rip->i_mode = conv2(norm, (int) dip->d1_mode);
rip->i_uid = conv2(norm, (int) dip->d1_uid );
rip->i_size = conv4(norm, dip->d1_size);
rip->i_mtime = conv4(norm, dip->d1_mtime);
rip->i_atime = rip->i_mtime;
rip->i_ctime = rip->i_mtime;
rip->i_nlinks = dip->d1_nlinks; /* 1 char */
rip->i_gid = dip->d1_gid; /* 1 char */
rip->i_ndzones = V1_NR_DZONES;
rip->i_nindirs = V1_INDIRECTS;
for (i = 0; i < V1_NR_TZONES; i++)
rip->i_zone[i] = conv2(norm, (int) dip->d1_zone[i]);
} else {
/* Copying V1.x inode to disk from the in-core table. */
dip->d1_mode = conv2(norm, (int) rip->i_mode);
dip->d1_uid = conv2(norm, (int) rip->i_uid );
dip->d1_size = conv4(norm, rip->i_size);
dip->d1_mtime = conv4(norm, rip->i_mtime);
dip->d1_nlinks = rip->i_nlinks; /* 1 char */
dip->d1_gid = rip->i_gid; /* 1 char */
for (i = 0; i < V1_NR_TZONES; i++)
dip->d1_zone[i] = conv2(norm, (int) rip->i_zone[i]);
}
}
/*===========================================================================*
* new_icopy *
*===========================================================================*/
PRIVATE void new_icopy(rip, dip, direction, norm)
register struct inode *rip; /* pointer to the in-core inode struct */
register d2_inode *dip; /* pointer to the d2_inode struct */
int direction; /* READING (from disk) or WRITING (to disk) */
int norm; /* TRUE = do not swap bytes; FALSE = swap */
{
/* Same as old_icopy, but to/from V2 disk layout. */
int i;
if (direction == READING) {
/* Copy V2.x inode to the in-core table, swapping bytes if need be. */
rip->i_mode = conv2(norm,dip->d2_mode);
rip->i_uid = conv2(norm,dip->d2_uid);
rip->i_nlinks = conv2(norm,dip->d2_nlinks);
rip->i_gid = conv2(norm,dip->d2_gid);
rip->i_size = conv4(norm,dip->d2_size);
rip->i_atime = conv4(norm,dip->d2_atime);
rip->i_ctime = conv4(norm,dip->d2_ctime);
rip->i_mtime = conv4(norm,dip->d2_mtime);
rip->i_ndzones = V2_NR_DZONES;
rip->i_nindirs = V2_INDIRECTS(rip->i_sp->s_block_size);
for (i = 0; i < V2_NR_TZONES; i++)
rip->i_zone[i] = conv4(norm, (long) dip->d2_zone[i]);
} else {
/* Copying V2.x inode to disk from the in-core table. */
dip->d2_mode = conv2(norm,rip->i_mode);
dip->d2_uid = conv2(norm,rip->i_uid);
dip->d2_nlinks = conv2(norm,rip->i_nlinks);
dip->d2_gid = conv2(norm,rip->i_gid);
dip->d2_size = conv4(norm,rip->i_size);
dip->d2_atime = conv4(norm,rip->i_atime);
dip->d2_ctime = conv4(norm,rip->i_ctime);
dip->d2_mtime = conv4(norm,rip->i_mtime);
for (i = 0; i < V2_NR_TZONES; i++)
dip->d2_zone[i] = conv4(norm, (long) rip->i_zone[i]);
}
}
/*===========================================================================*
* dup_inode *
*===========================================================================*/
PUBLIC void dup_inode(ip)
struct inode *ip; /* The inode to be duplicated. */
{
/* This routine is a simplified form of get_inode() for the case where
* the inode pointer is already known.
*/
ip->i_count++;
}
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