50b06261b6
Implemented by changing write_map to accept a WMAP_FREE flag. In that case, it doesn't update the datablock (creating indirect zones as necessary) pointer, but it frees the datablock if present. Also it frees the single and double indirect blocks if unused. This makes the implementation of truncate_inode() simpler. truncate_inode() now accepts a truncation length which makes implementing truncate() and ftruncate() simple. This also allowed implementing the F_FREESP fcntl().
367 lines
13 KiB
C
367 lines
13 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
|
|
* 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
|
|
*/
|
|
|
|
#include "fs.h"
|
|
#include "buf.h"
|
|
#include "file.h"
|
|
#include "fproc.h"
|
|
#include "inode.h"
|
|
#include "super.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));
|
|
|
|
/*===========================================================================*
|
|
* 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 a slot in the inode table, load the specified inode into it, and
|
|
* return a pointer to the slot. If 'dev' == NO_DEV, just return a free slot.
|
|
*/
|
|
|
|
register struct inode *rip, *xp;
|
|
|
|
/* Search the inode table both for (dev, numb) and a free slot. */
|
|
xp = NIL_INODE;
|
|
for (rip = &inode[0]; rip < &inode[NR_INODES]; rip++) {
|
|
if (rip->i_count > 0) { /* only check used slots for (dev, numb) */
|
|
if (rip->i_dev == dev && rip->i_num == numb) {
|
|
/* This is the inode that we are looking for. */
|
|
rip->i_count++;
|
|
return(rip); /* (dev, numb) found */
|
|
}
|
|
} else {
|
|
xp = rip; /* remember this free slot for later */
|
|
}
|
|
}
|
|
|
|
/* Inode we want is not currently in use. Did we find a free slot? */
|
|
if (xp == NIL_INODE) { /* inode table completely full */
|
|
err_code = ENFILE;
|
|
return(NIL_INODE);
|
|
}
|
|
|
|
/* A free inode slot has been located. Load the inode into it. */
|
|
xp->i_dev = dev;
|
|
xp->i_num = numb;
|
|
xp->i_count = 1;
|
|
if (dev != NO_DEV) rw_inode(xp, READING); /* get inode from disk */
|
|
xp->i_update = 0; /* all the times are initially up-to-date */
|
|
|
|
return(xp);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* 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 == 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_pipe = NO_PIPE; /* should always be cleared */
|
|
if (rip->i_dirt == DIRTY) rw_inode(rip, WRITING);
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* 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 %sdevice %d/%d\n",
|
|
sp->s_dev == root_dev ? "root " : "", 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 = fp->fp_effuid; /* file's uid is owner's */
|
|
rip->i_gid = fp->fp_effgid; /* 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++;
|
|
}
|