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phunix/servers/ext2/inode.c

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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
* update_times: update atime, ctime, and mtime
* rw_inode: read a disk block and extract an inode, or corresp. write
* dup_inode: indicate that someone else is using an inode table entry
* find_inode: retrieve pointer to inode in inode cache
*
* Created (MFS based):
* February 2010 (Evgeniy Ivanov)
*/
#include "fs.h"
#include <string.h>
#include "buf.h"
#include "inode.h"
#include "super.h"
#include <minix/vfsif.h>
FORWARD _PROTOTYPE( void icopy, (struct inode *rip, d_inode *dip,
int direction, int norm));
FORWARD _PROTOTYPE( void addhash_inode, (struct inode *node) );
FORWARD _PROTOTYPE( void unhash_inode, (struct inode *node) );
/*===========================================================================*
* fs_putnode *
*===========================================================================*/
PUBLIC int fs_putnode(void)
{
/* Find the inode specified by the request message and decrease its counter.*/
struct inode *rip;
int count;
rip = find_inode(fs_dev, (ino_t) fs_m_in.REQ_INODE_NR);
if (!rip) {
printf("%s:%d put_inode: inode #%d dev: %d not found\n", __FILE__,
__LINE__, (ino_t) fs_m_in.REQ_INODE_NR, fs_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;
put_inode(rip);
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 = NO_ENTRY;
TAILQ_INSERT_HEAD(&unused_inodes, rip, i_unused);
}
}
/*===========================================================================*
* addhash_inode *
*===========================================================================*/
PRIVATE void 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);
}
/*===========================================================================*
* unhash_inode *
*===========================================================================*/
PRIVATE void unhash_inode(struct inode *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 (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;
int hashi;
int i;
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) {
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(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;
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_last_dpos = 0; /* no dentries searched for yet */
rip->i_bsearch = NO_BLOCK;
rip->i_last_pos_bl_alloc = 0;
rip->i_last_dentry_size = 0;
rip->i_mountpoint= FALSE;
rip->i_preallocation = opt.use_prealloc;
rip->i_prealloc_count = rip->i_prealloc_index = 0;
for (i = 0; i < EXT2_PREALLOC_BLOCKS; i++) {
if (rip->i_prealloc_blocks[i] != NO_BLOCK) {
/* Actually this should never happen */
free_block(rip->i_sp, rip->i_prealloc_blocks[i]);
rip->i_prealloc_blocks[i] = NO_BLOCK;
ext2_debug("Warning: Unexpected preallocated block.");
}
}
/* Add to hash */
addhash_inode(rip);
return(rip);
}
/*===========================================================================*
* find_inode *
*===========================================================================*/
PUBLIC struct inode *find_inode(
dev_t dev, /* device on which inode resides */
ino_t numb /* inode number (ANSI: may not be unshort) */
)
{
/* 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 && rip->i_dev == dev) {
return(rip);
}
}
return(NULL);
}
/*===========================================================================*
* put_inode *
*===========================================================================*/
PUBLIC void put_inode(
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 == NULL)
return; /* checking here is easier than in caller */
if (rip->i_count < 1)
panic("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_links_count == NO_LINK) {
/* i_nlinks == NO_LINK means free the inode. */
/* return all the disk blocks */
/* Ignore errors by truncate_inode in case inode is a block
* special or character special file.
*/
(void) truncate_inode(rip, (off_t) 0);
/* free inode clears I_TYPE field, since it's used there */
rip->i_dirt = DIRTY;
free_inode(rip);
}
rip->i_mountpoint = FALSE;
if (rip->i_dirt == DIRTY) rw_inode(rip, WRITING);
discard_preallocated_blocks(rip); /* Return blocks to the filesystem */
if (rip->i_links_count == NO_LINK) {
/* free, put at the front of the LRU list */
unhash_inode(rip);
rip->i_num = NO_ENTRY;
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);
}
}
}
/*===========================================================================*
* update_times *
*===========================================================================*/
PUBLIC void update_times(
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(
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;
register struct group_desc *gd;
register d_inode *dip;
u32_t block_group_number;
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 */
block_group_number = (rip->i_num - 1) / sp->s_inodes_per_group;
gd = get_group_desc(block_group_number);
if (gd == NULL)
panic("can't get group_desc to read/write inode");
offset = ((rip->i_num - 1) % sp->s_inodes_per_group) * EXT2_INODE_SIZE(sp);
/* offset requires shifting, since each block contains several inodes,
* e.g. inode 2 is stored in bklock 0.
*/
b = (block_t) gd->inode_table + (offset >> sp->s_blocksize_bits);
bp = get_block(rip->i_dev, b, NORMAL);
offset &= (sp->s_block_size - 1);
dip = (d_inode*) (bp->b_data + offset);
/* 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;
}
icopy(rip, dip, rw_flag, TRUE);
put_block(bp, INODE_BLOCK);
rip->i_dirt = CLEAN;
}
/*===========================================================================*
* icopy *
*===========================================================================*/
PRIVATE void icopy(
register struct inode *rip, /* pointer to the in-core inode struct */
register d_inode *dip, /* pointer to the on-disk struct */
int direction, /* READING (from disk) or WRITING (to disk) */
int norm /* TRUE = do not swap bytes; FALSE = swap */
)
{
int i;
if (direction == READING) {
/* Copy inode to the in-core table, swapping bytes if need be. */
rip->i_mode = conv2(norm,dip->i_mode);
rip->i_uid = conv2(norm,dip->i_uid);
rip->i_size = conv4(norm,dip->i_size);
rip->i_atime = conv4(norm,dip->i_atime);
rip->i_ctime = conv4(norm,dip->i_ctime);
rip->i_mtime = conv4(norm,dip->i_mtime);
rip->i_dtime = conv4(norm,dip->i_dtime);
rip->i_gid = conv2(norm,dip->i_gid);
rip->i_links_count = conv2(norm,dip->i_links_count);
rip->i_blocks = conv4(norm,dip->i_blocks);
rip->i_flags = conv4(norm,dip->i_flags);
/* Minix doesn't touch osd1 and osd2 either, so just copy. */
memcpy(&rip->osd1, &dip->osd1, sizeof(rip->osd1));
for (i = 0; i < EXT2_N_BLOCKS; i++)
rip->i_block[i] = conv4(norm, dip->i_block[i]);
rip->i_generation = conv4(norm,dip->i_generation);
rip->i_file_acl = conv4(norm,dip->i_file_acl);
rip->i_dir_acl = conv4(norm,dip->i_dir_acl);
rip->i_faddr = conv4(norm,dip->i_faddr);
memcpy(&rip->osd2, &dip->osd2, sizeof(rip->osd2));
} else {
/* Copying inode to disk from the in-core table. */
dip->i_mode = conv2(norm,rip->i_mode);
dip->i_uid = conv2(norm,rip->i_uid);
dip->i_size = conv4(norm,rip->i_size);
dip->i_atime = conv4(norm,rip->i_atime);
dip->i_ctime = conv4(norm,rip->i_ctime);
dip->i_mtime = conv4(norm,rip->i_mtime);
dip->i_dtime = conv4(norm,rip->i_dtime);
dip->i_gid = conv2(norm,rip->i_gid);
dip->i_links_count = conv2(norm,rip->i_links_count);
dip->i_blocks = conv4(norm,rip->i_blocks);
dip->i_flags = conv4(norm,rip->i_flags);
/* Minix doesn't touch osd1 and osd2 either, so just copy. */
memcpy(&dip->osd1, &rip->osd1, sizeof(dip->osd1));
for (i = 0; i < EXT2_N_BLOCKS; i++)
dip->i_block[i] = conv4(norm, rip->i_block[i]);
dip->i_generation = conv4(norm,rip->i_generation);
dip->i_file_acl = conv4(norm,rip->i_file_acl);
dip->i_dir_acl = conv4(norm,rip->i_dir_acl);
dip->i_faddr = conv4(norm,rip->i_faddr);
memcpy(&dip->osd2, &rip->osd2, sizeof(dip->osd2));
}
}
/*===========================================================================*
* dup_inode *
*===========================================================================*/
PUBLIC void dup_inode(
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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