4.1cBSD/a/sys/sys/ufs_inode.c
/* ufs_inode.c 4.34 83/03/15 */
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mount.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/inode.h"
#include "../h/fs.h"
#include "../h/conf.h"
#include "../h/buf.h"
#ifdef QUOTA
#include "../h/quota.h"
#endif
#include "../h/kernel.h"
#define INOHSZ 63
#if ((INOHSZ&(INOHSZ-1)) == 0)
#define INOHASH(dev,ino) (((dev)+(ino))&(INOHSZ-1))
#else
#define INOHASH(dev,ino) (((unsigned)((dev)+(ino)))%INOHSZ)
#endif
union ihead { /* inode LRU cache, Chris Maltby */
union ihead *ih_head[2];
struct inode *ih_chain[2];
} ihead[INOHSZ];
struct inode *ifreeh, **ifreet;
/*
* Initialize hash links for inodes
* and build inode free list.
*/
ihinit()
{
register int i;
register struct inode *ip = inode;
register union ihead *ih = ihead;
for (i = INOHSZ; --i >= 0; ih++) {
ih->ih_head[0] = ih;
ih->ih_head[1] = ih;
}
ifreeh = ip;
ifreet = &ip->i_freef;
ip->i_freeb = &ifreeh;
ip->i_forw = ip;
ip->i_back = ip;
for (i = ninode; --i > 0; ) {
++ip;
ip->i_forw = ip;
ip->i_back = ip;
*ifreet = ip;
ip->i_freeb = ifreet;
ifreet = &ip->i_freef;
}
ip->i_freef = NULL;
}
#ifdef notdef
/*
* Find an inode if it is incore.
* This is the equivalent, for inodes,
* of ``incore'' in bio.c or ``pfind'' in subr.c.
*/
struct inode *
ifind(dev, ino)
dev_t dev;
ino_t ino;
{
register struct inode *ip;
register union ihead *ih;
ih = &ihead[INOHASH(dev, ino)];
for (ip = ih->ih_chain[0]; ip != (struct inode *)ih; ip = ip->i_forw)
if (ino==ip->i_number && dev==ip->i_dev)
return (ip);
return ((struct inode *)0);
}
#endif notdef
/*
* Look up an inode by device,inumber.
* If it is in core (in the inode structure),
* honor the locking protocol.
* If it is not in core, read it in from the
* specified device.
* If the inode is mounted on, perform
* the indicated indirection.
* In all cases, a pointer to a locked
* inode structure is returned.
*
* panic: no imt -- if the mounted file
* system is not in the mount table.
* "cannot happen"
*/
struct inode *
iget(dev, fs, ino)
dev_t dev;
register struct fs *fs;
ino_t ino;
{
register struct inode *ip;
register union ihead *ih;
register struct mount *mp;
register struct buf *bp;
register struct dinode *dp;
register struct inode *iq;
loop:
if (getfs(dev) != fs)
panic("iget: bad fs");
ih = &ihead[INOHASH(dev, ino)];
for (ip = ih->ih_chain[0]; ip != (struct inode *)ih; ip = ip->i_forw)
if (ino == ip->i_number && dev == ip->i_dev) {
if ((ip->i_flag&ILOCKED) != 0) {
ip->i_flag |= IWANT;
sleep((caddr_t)ip, PINOD);
goto loop;
}
if ((ip->i_flag&IMOUNT) != 0) {
for (mp = &mount[0]; mp < &mount[NMOUNT]; mp++)
if(mp->m_inodp == ip) {
dev = mp->m_dev;
fs = mp->m_bufp->b_un.b_fs;
ino = ROOTINO;
goto loop;
}
panic("no imt");
}
if (ip->i_count == 0) { /* ino on free list */
if (iq = ip->i_freef)
iq->i_freeb = ip->i_freeb;
else
ifreet = ip->i_freeb;
*ip->i_freeb = iq;
ip->i_freef = NULL;
ip->i_freeb = NULL;
}
ip->i_count++;
ip->i_flag |= ILOCKED;
return(ip);
}
if ((ip = ifreeh) == NULL) {
tablefull("inode");
u.u_error = ENFILE;
return(NULL);
}
if (iq = ip->i_freef)
iq->i_freeb = &ifreeh;
ifreeh = iq;
ip->i_freef = NULL;
ip->i_freeb = NULL;
/*
* Now to take inode off the hash chain it was on
* (initially, or after an iflush, it is on a "hash chain"
* consisting entirely of itself, and pointed to by no-one,
* but that doesn't matter), and put it on the chain for
* its new (ino, dev) pair
*/
remque(ip);
insque(ip, ih);
#ifdef QUOTA
dqrele(ip->i_dquot);
#endif
ip->i_dev = dev;
ip->i_fs = fs;
ip->i_number = ino;
ip->i_flag = ILOCKED;
ip->i_count++;
ip->i_lastr = 0;
bp = bread(dev, fsbtodb(fs, itod(fs, ino)), (int)fs->fs_bsize);
/*
* Check I/O errors
*/
if ((bp->b_flags&B_ERROR) != 0) {
brelse(bp);
/*
* the inode doesn't contain anything useful, so it would
* be misleading to leave it on its hash chain.
* 'iput' will take care of putting it back on the free list.
*/
remque(ip);
ip->i_forw = ip;
ip->i_back = ip;
/*
* we also loose its inumber, just in case (as iput
* doesn't do that any more) - but as it isn't on its
* hash chain, I doubt if this is really necessary .. kre
* (probably the two methods are interchangable)
*/
ip->i_number = 0;
#ifdef QUOTA
ip->i_dquot = NODQUOT;
#endif
iput(ip);
return(NULL);
}
dp = bp->b_un.b_dino;
dp += itoo(fs, ino);
ip->i_ic = dp->di_ic;
brelse(bp);
#ifdef QUOTA
if (ip->i_mode == 0)
ip->i_dquot = NODQUOT;
else
ip->i_dquot = inoquota(ip);
#endif
return (ip);
}
/*
* Decrement reference count of
* an inode structure.
* On the last reference,
* write the inode out and if necessary,
* truncate and deallocate the file.
*/
iput(ip)
register struct inode *ip;
{
if ((ip->i_flag & ILOCKED) == 0)
panic("iput");
iunlock(ip);
irele(ip);
}
irele(ip)
register struct inode *ip;
{
int mode;
if (ip->i_count == 1) {
ip->i_flag |= ILOCKED;
if (ip->i_nlink <= 0) {
itrunc(ip, (u_long)0);
mode = ip->i_mode;
ip->i_mode = 0;
ip->i_rdev = 0;
ip->i_flag |= IUPD|ICHG;
ifree(ip, ip->i_number, mode);
#ifdef QUOTA
(void)chkiq(ip->i_dev, ip, ip->i_uid, 0);
dqrele(ip->i_dquot);
ip->i_dquot = NODQUOT;
#endif
}
IUPDAT(ip, &time, &time, 0);
iunlock(ip);
ip->i_flag = 0;
/*
* Put the inode on the end of the free list.
* Possibly in some cases it would be better to
* put the inode at the head of the free list,
* (eg: where i_mode == 0 || i_number == 0)
* but I will think about that later .. kre
* (i_number is rarely 0 - only after an i/o error in iget,
* where i_mode == 0, the inode will probably be wanted
* again soon for an ialloc, so possibly we should keep it)
*/
if (ifreeh) {
*ifreet = ip;
ip->i_freeb = ifreet;
} else {
ifreeh = ip;
ip->i_freeb = &ifreeh;
}
ip->i_freef = NULL;
ifreet = &ip->i_freef;
}
ip->i_count--;
}
/*
* Check accessed and update flags on
* an inode structure.
* If any is on, update the inode
* with the current time.
* If waitfor is given, then must insure
* i/o order so wait for write to complete.
*/
iupdat(ip, ta, tm, waitfor)
register struct inode *ip;
struct timeval *ta, *tm;
int waitfor;
{
register struct buf *bp;
struct dinode *dp;
register struct fs *fp;
fp = ip->i_fs;
if ((ip->i_flag & (IUPD|IACC|ICHG)) != 0) {
if (fp->fs_ronly)
return;
bp = bread(ip->i_dev, fsbtodb(fp, itod(fp, ip->i_number)),
(int)fp->fs_bsize);
if (bp->b_flags & B_ERROR) {
brelse(bp);
return;
}
if (ip->i_flag&IACC)
ip->i_atime = ta->tv_sec;
if (ip->i_flag&IUPD)
ip->i_mtime = tm->tv_sec;
if (ip->i_flag&ICHG)
ip->i_ctime = time.tv_sec;
ip->i_flag &= ~(IUPD|IACC|ICHG);
dp = bp->b_un.b_dino + itoo(fp, ip->i_number);
dp->di_ic = ip->i_ic;
if (waitfor)
bwrite(bp);
else
bdwrite(bp);
}
}
#define SINGLE 0 /* index of single indirect block */
#define DOUBLE 1 /* index of double indirect block */
#define TRIPLE 2 /* index of triple indirect block */
/*
* Truncate the inode ip to at most
* length size. Free affected disk
* blocks -- the blocks of the file
* are removed in reverse order.
*
* NB: triple indirect blocks are untested.
*/
itrunc(oip, length)
struct inode *oip;
u_long length;
{
register i;
register daddr_t lastblock;
daddr_t bn, lastiblock[NIADDR];
register struct fs *fs;
register struct inode *ip;
struct inode tip;
int level;
#ifdef QUOTA
long blocksreleased = 0, nblocks;
long indirtrunc();
#endif
if (oip->i_size <= length)
return;
/*
* Calculate index into inode's block list of
* last direct and indirect blocks (if any)
* which we want to keep. Lastblock is -1 when
* the file is truncated to 0.
*/
fs = oip->i_fs;
lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
lastiblock[SINGLE] = lastblock - NDADDR;
lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
#ifdef QUOTA
nblocks = fs->fs_bsize / DEV_BSIZE;
#endif
/*
* Update size of file and block pointers
* on disk before we start freeing blocks.
* If we crash before free'ing blocks below,
* the blocks will be returned to the free list.
* lastiblock values are also normalized to -1
* for calls to indirtrunc below.
* (? fsck doesn't check validity of pointers in indirect blocks)
*/
tip = *oip;
for (level = TRIPLE; level >= SINGLE; level--)
if (lastiblock[level] < 0) {
oip->i_ib[level] = 0;
lastiblock[level] = -1;
}
for (i = NDADDR - 1; i > lastblock; i--)
oip->i_db[i] = 0;
oip->i_size = length;
oip->i_flag |= ICHG|IUPD;
iupdat(oip, &time, &time, 1);
ip = &tip;
/*
* Indirect blocks first.
*/
for (level = TRIPLE; level >= SINGLE; level--) {
bn = ip->i_ib[level];
if (bn != 0) {
#ifdef QUOTA
blocksreleased +=
#endif
indirtrunc(ip, bn, lastiblock[level], level);
if (lastiblock[level] < 0) {
ip->i_ib[level] = 0;
free(ip, bn, (off_t)fs->fs_bsize);
#ifdef QUOTA
blocksreleased += nblocks;
#endif
}
}
if (lastiblock[level] >= 0)
goto done;
}
/*
* All whole direct blocks or frags.
*/
for (i = NDADDR - 1; i > lastblock; i--) {
register int size;
bn = ip->i_db[i];
if (bn == 0)
continue;
ip->i_db[i] = 0;
size = (off_t)blksize(fs, ip, i);
free(ip, bn, size);
#ifdef QUOTA
blocksreleased += size / DEV_BSIZE;
#endif
}
if (lastblock < 0)
goto done;
/*
* Finally, look for a change in size of the
* last direct block; release any frags.
*/
bn = ip->i_db[lastblock];
if (bn != 0) {
int oldspace, newspace;
/*
* Calculate amount of space we're giving
* back as old block size minus new block size.
*/
oldspace = blksize(fs, ip, lastblock);
ip->i_size = length;
newspace = blksize(fs, ip, lastblock);
if (newspace == 0)
panic("itrunc: newspace");
if (oldspace - newspace > 0) {
/*
* Block number of space to be free'd is
* the old block # plus the number of frags
* required for the storage we're keeping.
*/
bn += numfrags(fs, newspace);
free(ip, bn, oldspace - newspace);
#ifdef QUOTA
blocksreleased += (oldspace - newspace) / DEV_BSIZE;
#endif
}
}
done:
/* BEGIN PARANOIA */
for (level = SINGLE; level <= TRIPLE; level++)
if (ip->i_ib[level] != oip->i_ib[level])
panic("itrunc1");
for (i = 0; i < NDADDR; i++)
if (ip->i_db[i] != oip->i_db[i])
panic("itrunc2");
/* END PARANOIA */
#ifdef QUOTA
(void) chkdq(ip, -blocksreleased, 0);
#endif
}
/*
* Release blocks associated with the inode ip and
* stored in the indirect block bn. Blocks are free'd
* in LIFO order up to (but not including) lastbn. If
* level is greater than SINGLE, the block is an indirect
* block and recursive calls to indirtrunc must be used to
* cleanse other indirect blocks.
*
* NB: triple indirect blocks are untested.
*/
#ifdef QUOTA
long
#endif
indirtrunc(ip, bn, lastbn, level)
register struct inode *ip;
daddr_t bn, lastbn;
int level;
{
register int i;
struct buf *bp, *copy;
register daddr_t *bap;
register struct fs *fs = ip->i_fs;
daddr_t nb, last;
long factor;
#ifdef QUOTA
int blocksreleased = 0, nblocks;
#endif
/*
* Calculate index in current block of last
* block to be kept. -1 indicates the entire
* block so we need not calculate the index.
*/
factor = 1;
for (i = SINGLE; i < level; i++)
factor *= NINDIR(fs);
last = lastbn;
if (lastbn > 0)
last /= factor;
#ifdef QUOTA
nblocks = fs->fs_bsize / DEV_BSIZE;
#endif
/*
* Get buffer of block pointers, zero those
* entries corresponding to blocks to be free'd,
* and update on disk copy first.
*/
copy = geteblk((int)fs->fs_bsize);
bp = bread(ip->i_dev, fsbtodb(fs, bn), (int)fs->fs_bsize);
if (bp->b_flags&B_ERROR) {
brelse(copy);
brelse(bp);
#ifdef QUOTA
return (0);
#else
return;
#endif
}
bap = bp->b_un.b_daddr;
bcopy((caddr_t)bap, (caddr_t)copy->b_un.b_daddr, (u_int)fs->fs_bsize);
bzero((caddr_t)&bap[last + 1],
(u_int)(NINDIR(fs) - (last + 1)) * sizeof (daddr_t));
bwrite(bp);
bp = copy, bap = bp->b_un.b_daddr;
/*
* Recursively free totally unused blocks.
*/
for (i = NINDIR(fs) - 1; i > last; i--) {
nb = bap[i];
if (nb == 0)
continue;
if (level > SINGLE)
#ifdef QUOTA
blocksreleased +=
#endif
indirtrunc(ip, nb, (daddr_t)-1, level - 1);
free(ip, nb, (int)fs->fs_bsize);
#ifdef QUOTA
blocksreleased += nblocks;
#endif
}
/*
* Recursively free last partial block.
*/
if (level > SINGLE && lastbn >= 0) {
last = lastbn % factor;
nb = bap[i];
if (nb != 0)
#ifdef QUOTA
blocksreleased +=
#endif
indirtrunc(ip, nb, last, level - 1);
}
brelse(bp);
#ifdef QUOTA
return (blocksreleased);
#endif
}
/*
* remove any inodes in the inode cache belonging to dev
*
* There should not be any active ones, return error if any are found
* (nb: this is a user error, not a system err)
*
* Also, count the references to dev by block devices - this really
* has nothing to do with the object of the procedure, but as we have
* to scan the inode table here anyway, we might as well get the
* extra benefit.
*
* this is called from sumount()/sys3.c when dev is being unmounted
*/
#ifdef QUOTA
iflush(dev, iq)
dev_t dev;
struct inode *iq;
#else
iflush(dev)
dev_t dev;
#endif
{
register struct inode *ip;
register open = 0;
for (ip = inode; ip < inodeNINODE; ip++) {
#ifdef QUOTA
if (ip != iq && ip->i_dev == dev)
#else
if (ip->i_dev == dev)
#endif
if (ip->i_count)
return(-1);
else {
remque(ip);
ip->i_forw = ip;
ip->i_back = ip;
/*
* as i_count == 0, the inode was on the free
* list already, just leave it there, it will
* fall off the bottom eventually. We could
* perhaps move it to the head of the free
* list, but as umounts are done so
* infrequently, we would gain very little,
* while making the code bigger.
*/
#ifdef QUOTA
dqrele(ip->i_dquot);
ip->i_dquot = NODQUOT;
#endif
}
else if (ip->i_count && (ip->i_mode&IFMT)==IFBLK &&
ip->i_rdev == dev)
open++;
}
return (open);
}
/*
* Lock an inode. If its already locked, set the WANT bit and sleep.
*/
ilock(ip)
register struct inode *ip;
{
ILOCK(ip);
}
/*
* Unlock an inode. If WANT bit is on, wakeup.
*/
iunlock(ip)
register struct inode *ip;
{
IUNLOCK(ip);
}