-/* Copyright (c) 1981 Regents of the University of California */
-
-static char vers[] = "@(#)lfs_alloc.c 1.21 %G%";
-
-/* alloc.c 4.8 81/03/08 */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/mount.h"
-#include "../h/fs.h"
-#include "../h/conf.h"
-#include "../h/buf.h"
-#include "../h/inode.h"
-#include "../h/user.h"
-
-extern u_long hashalloc();
-extern ino_t ialloccg();
-extern daddr_t alloccg();
-extern daddr_t alloccgblk();
-extern daddr_t fragextend();
-extern daddr_t blkpref();
-extern daddr_t mapsearch();
-extern int inside[], around[];
-extern unsigned char *fragtbl[];
-
-/*
- * Allocate a block in the file system.
- *
- * The size of the requested block is given, which must be some
- * multiple of fs_fsize and <= fs_bsize.
- * A preference may be optionally specified. If a preference is given
- * the following hierarchy is used to allocate a block:
- * 1) allocate the requested block.
- * 2) allocate a rotationally optimal block in the same cylinder.
- * 3) allocate a block in the same cylinder group.
- * 4) quadradically rehash into other cylinder groups, until an
- * available block is located.
- * If no block preference is given the following heirarchy is used
- * to allocate a block:
- * 1) allocate a block in the cylinder group that contains the
- * inode for the file.
- * 2) quadradically rehash into other cylinder groups, until an
- * available block is located.
- */
-struct buf *
-alloc(ip, bpref, size)
- register struct inode *ip;
- daddr_t bpref;
- int size;
-{
- daddr_t bno;
- register struct fs *fs;
- register struct buf *bp;
- int cg;
-
- fs = ip->i_fs;
- if ((unsigned)size > fs->fs_bsize || fragoff(fs, size) != 0)
- panic("alloc: bad size");
- if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0)
- goto nospace;
- if (u.u_uid != 0 &&
- fs->fs_cstotal.cs_nbfree * fs->fs_frag + fs->fs_cstotal.cs_nffree <
- fs->fs_dsize * fs->fs_minfree / 100)
- goto nospace;
- if (bpref >= fs->fs_size)
- bpref = 0;
- if (bpref == 0)
- cg = itog(fs, ip->i_number);
- else
- cg = dtog(fs, bpref);
- bno = (daddr_t)hashalloc(ip, cg, (long)bpref, size, alloccg);
- if (bno == 0)
- goto nospace;
- bp = getblk(ip->i_dev, fsbtodb(fs, bno), size);
- clrbuf(bp);
- return (bp);
-nospace:
- fserr(fs, "file system full");
- uprintf("\n%s: write failed, file system is full\n", fs->fs_fsmnt);
- u.u_error = ENOSPC;
- return (NULL);
-}
-
-/*
- * Reallocate a fragment to a bigger size
- *
- * The number and size of the old block is given, and a preference
- * and new size is also specified. The allocator attempts to extend
- * the original block. Failing that, the regular block allocator is
- * invoked to get an appropriate block.
- */
-struct buf *
-realloccg(ip, bprev, bpref, osize, nsize)
- register struct inode *ip;
- daddr_t bprev, bpref;
- int osize, nsize;
-{
- daddr_t bno;
- register struct fs *fs;
- register struct buf *bp, *obp;
- caddr_t cp;
- int cg;
-
- fs = ip->i_fs;
- if ((unsigned)osize > fs->fs_bsize || fragoff(fs, osize) != 0 ||
- (unsigned)nsize > fs->fs_bsize || fragoff(fs, nsize) != 0)
- panic("realloccg: bad size");
- if (u.u_uid != 0 &&
- fs->fs_cstotal.cs_nbfree * fs->fs_frag + fs->fs_cstotal.cs_nffree <
- fs->fs_dsize * fs->fs_minfree / 100)
- goto nospace;
- if (bprev == 0)
- panic("realloccg: bad bprev");
- cg = dtog(fs, bprev);
- bno = fragextend(ip, cg, (long)bprev, osize, nsize);
- if (bno != 0) {
- bp = bread(ip->i_dev, fsbtodb(fs, bno), osize);
- if (bp->b_flags & B_ERROR) {
- brelse(bp);
- return (NULL);
- }
- bp->b_bcount = nsize;
- blkclr(bp->b_un.b_addr + osize, nsize - osize);
- return (bp);
- }
- if (bpref >= fs->fs_size)
- bpref = 0;
- bno = (daddr_t)hashalloc(ip, cg, (long)bpref, nsize, alloccg);
- if (bno != 0) {
- /*
- * make a new copy
- */
- obp = bread(ip->i_dev, fsbtodb(fs, bprev), osize);
- if (obp->b_flags & B_ERROR) {
- brelse(obp);
- return (NULL);
- }
- bp = getblk(ip->i_dev, fsbtodb(fs, bno), nsize);
- cp = bp->b_un.b_addr;
- bp->b_un.b_addr = obp->b_un.b_addr;
- obp->b_un.b_addr = cp;
- obp->b_flags |= B_INVAL;
- brelse(obp);
- fre(ip, bprev, (off_t)osize);
- blkclr(bp->b_un.b_addr + osize, nsize - osize);
- return (bp);
- }
-nospace:
- /*
- * no space available
- */
- fserr(fs, "file system full");
- uprintf("\n%s: write failed, file system is full\n", fs->fs_fsmnt);
- u.u_error = ENOSPC;
- return (NULL);
-}
-
-/*
- * Allocate an inode in the file system.
- *
- * A preference may be optionally specified. If a preference is given
- * the following hierarchy is used to allocate an inode:
- * 1) allocate the requested inode.
- * 2) allocate an inode in the same cylinder group.
- * 3) quadradically rehash into other cylinder groups, until an
- * available inode is located.
- * If no inode preference is given the following heirarchy is used
- * to allocate an inode:
- * 1) allocate an inode in cylinder group 0.
- * 2) quadradically rehash into other cylinder groups, until an
- * available inode is located.
- */
-struct inode *
-ialloc(pip, ipref, mode)
- register struct inode *pip;
- ino_t ipref;
- int mode;
-{
- ino_t ino;
- register struct fs *fs;
- register struct inode *ip;
- int cg;
-
- fs = pip->i_fs;
- if (fs->fs_cstotal.cs_nifree == 0)
- goto noinodes;
- if (ipref >= fs->fs_ncg * fs->fs_ipg)
- ipref = 0;
- cg = itog(fs, ipref);
- ino = (ino_t)hashalloc(pip, cg, (long)ipref, mode, ialloccg);
- if (ino == 0)
- goto noinodes;
- ip = iget(pip->i_dev, pip->i_fs, ino);
- if (ip == NULL) {
- ifree(ip, ino, 0);
- return (NULL);
- }
- if (ip->i_mode)
- panic("ialloc: dup alloc");
- return (ip);
-noinodes:
- fserr(fs, "out of inodes");
- uprintf("\n%s: create/symlink failed, no inodes free\n", fs->fs_fsmnt);
- u.u_error = ENOSPC;
- return (NULL);
-}
-
-/*
- * Find a cylinder to place a directory.
- *
- * The policy implemented by this algorithm is to select from
- * among those cylinder groups with above the average number of
- * free inodes, the one with the smallest number of directories.
- */
-dirpref(fs)
- register struct fs *fs;
-{
- int cg, minndir, mincg, avgifree;
-
- avgifree = fs->fs_cstotal.cs_nifree / fs->fs_ncg;
- minndir = fs->fs_ipg;
- mincg = 0;
- for (cg = 0; cg < fs->fs_ncg; cg++)
- if (fs->fs_cs(fs, cg).cs_ndir < minndir &&
- fs->fs_cs(fs, cg).cs_nifree >= avgifree) {
- mincg = cg;
- minndir = fs->fs_cs(fs, cg).cs_ndir;
- }
- return (fs->fs_ipg * mincg);
-}
-
-/*
- * Select a cylinder to place a large block of data.
- *
- * The policy implemented by this algorithm is to maintain a
- * rotor that sweeps the cylinder groups. When a block is
- * needed, the rotor is advanced until a cylinder group with
- * greater than the average number of free blocks is found.
- */
-daddr_t
-blkpref(fs)
- register struct fs *fs;
-{
- int cg, avgbfree;
-
- avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
- for (cg = fs->fs_cgrotor + 1; cg < fs->fs_ncg; cg++)
- if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
- fs->fs_cgrotor = cg;
- return (fs->fs_fpg * cg + fs->fs_frag);
- }
- for (cg = 0; cg <= fs->fs_cgrotor; cg++)
- if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
- fs->fs_cgrotor = cg;
- return (fs->fs_fpg * cg + fs->fs_frag);
- }
- return (NULL);
-}
-
-/*
- * Implement the cylinder overflow algorithm.
- *
- * The policy implemented by this algorithm is:
- * 1) allocate the block in its requested cylinder group.
- * 2) quadradically rehash on the cylinder group number.
- * 3) brute force search for a free block.
- */
-/*VARARGS5*/
-u_long
-hashalloc(ip, cg, pref, size, allocator)
- struct inode *ip;
- int cg;
- long pref;
- int size; /* size for data blocks, mode for inodes */
- u_long (*allocator)();
-{
- register struct fs *fs;
- long result;
- int i, icg = cg;
-
- fs = ip->i_fs;
- /*
- * 1: preferred cylinder group
- */
- result = (*allocator)(ip, cg, pref, size);
- if (result)
- return (result);
- /*
- * 2: quadratic rehash
- */
- for (i = 1; i < fs->fs_ncg; i *= 2) {
- cg += i;
- if (cg >= fs->fs_ncg)
- cg -= fs->fs_ncg;
- result = (*allocator)(ip, cg, 0, size);
- if (result)
- return (result);
- }
- /*
- * 3: brute force search
- */
- cg = icg;
- for (i = 0; i < fs->fs_ncg; i++) {
- result = (*allocator)(ip, cg, 0, size);
- if (result)
- return (result);
- cg++;
- if (cg == fs->fs_ncg)
- cg = 0;
- }
- return (NULL);
-}
-
-/*
- * Determine whether a fragment can be extended.
- *
- * Check to see if the necessary fragments are available, and
- * if they are, allocate them.
- */
-daddr_t
-fragextend(ip, cg, bprev, osize, nsize)
- struct inode *ip;
- int cg;
- long bprev;
- int osize, nsize;
-{
- register struct fs *fs;
- register struct buf *bp;
- register struct cg *cgp;
- long bno;
- int frags, bbase;
- int i;
-
- fs = ip->i_fs;
- frags = numfrags(fs, nsize);
- bbase = fragoff(fs, bprev);
- if (bbase > (bprev + frags - 1) % fs->fs_frag) {
- /* cannot extend across a block boundry */
- return (NULL);
- }
- bp = bread(ip->i_dev, fsbtodb(fs, cgtod(fs, cg)), fs->fs_bsize);
- if (bp->b_flags & B_ERROR) {
- brelse(bp);
- return (NULL);
- }
- cgp = bp->b_un.b_cg;
- bno = dtogd(fs, bprev);
- for (i = numfrags(fs, osize); i < frags; i++)
- if (isclr(cgp->cg_free, bno + i)) {
- brelse(bp);
- return (NULL);
- }
- /*
- * the current fragment can be extended
- * deduct the count on fragment being extended into
- * increase the count on the remaining fragment (if any)
- * allocate the extended piece
- */
- for (i = frags; i < fs->fs_frag - bbase; i++)
- if (isclr(cgp->cg_free, bno + i))
- break;
- cgp->cg_frsum[i - numfrags(fs, osize)]--;
- if (i != frags)
- cgp->cg_frsum[i - frags]++;
- for (i = numfrags(fs, osize); i < frags; i++) {
- clrbit(cgp->cg_free, bno + i);
- cgp->cg_cs.cs_nffree--;
- fs->fs_cstotal.cs_nffree--;
- fs->fs_cs(fs, cg).cs_nffree--;
- }
- fs->fs_fmod++;
- bdwrite(bp);
- return (bprev);
-}
-
-/*
- * Determine whether a block can be allocated.
- *
- * Check to see if a block of the apprpriate size is available,
- * and if it is, allocate it.
- */
-daddr_t
-alloccg(ip, cg, bpref, size)
- struct inode *ip;
- int cg;
- daddr_t bpref;
- int size;
-{
- register struct fs *fs;
- register struct buf *bp;
- register struct cg *cgp;
- int bno, frags;
- int allocsiz;
- register int i;
-
- fs = ip->i_fs;
- if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
- return (NULL);
- bp = bread(ip->i_dev, fsbtodb(fs, cgtod(fs, cg)), fs->fs_bsize);
- if (bp->b_flags & B_ERROR) {
- brelse(bp);
- return (NULL);
- }
- cgp = bp->b_un.b_cg;
- if (size == fs->fs_bsize) {
- bno = alloccgblk(fs, cgp, bpref);
- bdwrite(bp);
- return (bno);
- }
- /*
- * check to see if any fragments are already available
- * allocsiz is the size which will be allocated, hacking
- * it down to a smaller size if necessary
- */
- frags = numfrags(fs, size);
- for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++)
- if (cgp->cg_frsum[allocsiz] != 0)
- break;
- if (allocsiz == fs->fs_frag) {
- /*
- * no fragments were available, so a block will be
- * allocated, and hacked up
- */
- if (cgp->cg_cs.cs_nbfree == 0) {
- brelse(bp);
- return (NULL);
- }
- bno = alloccgblk(fs, cgp, bpref);
- bpref = dtogd(fs, bno);
- for (i = frags; i < fs->fs_frag; i++)
- setbit(cgp->cg_free, bpref + i);
- i = fs->fs_frag - frags;
- cgp->cg_cs.cs_nffree += i;
- fs->fs_cstotal.cs_nffree += i;
- fs->fs_cs(fs, cg).cs_nffree += i;
- cgp->cg_frsum[i]++;
- bdwrite(bp);
- return (bno);
- }
- bno = mapsearch(fs, cgp, bpref, allocsiz);
- if (bno == 0)
- return (NULL);
- for (i = 0; i < frags; i++)
- clrbit(cgp->cg_free, bno + i);
- cgp->cg_cs.cs_nffree -= frags;
- fs->fs_cstotal.cs_nffree -= frags;
- fs->fs_cs(fs, cg).cs_nffree -= frags;
- cgp->cg_frsum[allocsiz]--;
- if (frags != allocsiz)
- cgp->cg_frsum[allocsiz - frags]++;
- bdwrite(bp);
- return (cg * fs->fs_fpg + bno);
-}
-
-/*
- * Allocate a block in a cylinder group.
- *
- * This algorithm implements the following policy:
- * 1) allocate the requested block.
- * 2) allocate a rotationally optimal block in the same cylinder.
- * 3) allocate the next available block on the block rotor for the
- * specified cylinder group.
- * Note that this routine only allocates fs_bsize blocks; these
- * blocks may be fragmented by the routine that allocates them.
- */
-daddr_t
-alloccgblk(fs, cgp, bpref)
- register struct fs *fs;
- register struct cg *cgp;
- daddr_t bpref;
-{
- daddr_t bno;
- int cylno, pos, delta;
- short *cylbp;
- register int i;
-
- if (bpref == 0) {
- bpref = cgp->cg_rotor;
- goto norot;
- }
- bpref &= ~(fs->fs_frag - 1);
- bpref = dtogd(fs, bpref);
- /*
- * if the requested block is available, use it
- */
- if (isblock(fs, cgp->cg_free, bpref/fs->fs_frag)) {
- bno = bpref;
- goto gotit;
- }
- /*
- * check for a block available on the same cylinder
- */
- cylno = cbtocylno(fs, bpref);
- if (cgp->cg_btot[cylno] == 0)
- goto norot;
- if (fs->fs_cpc == 0) {
- /*
- * block layout info is not available, so just have
- * to take any block in this cylinder.
- */
- bpref = howmany(fs->fs_spc * cylno, NSPF(fs));
- goto norot;
- }
- /*
- * find a block that is rotationally optimal
- */
- cylbp = cgp->cg_b[cylno];
- if (fs->fs_rotdelay == 0) {
- pos = cbtorpos(fs, bpref);
- } else {
- /*
- * here we convert ms of delay to frags as:
- * (frags) = (ms) * (rev/sec) * (sect/rev) /
- * ((sect/frag) * (ms/sec))
- * then round up to the next rotational position
- */
- bpref += fs->fs_rotdelay * fs->fs_rps * fs->fs_nsect /
- (NSPF(fs) * 1000);
- pos = cbtorpos(fs, bpref);
- pos = (pos + 1) % NRPOS;
- }
- /*
- * check the summary information to see if a block is
- * available in the requested cylinder starting at the
- * optimal rotational position and proceeding around.
- */
- for (i = pos; i < NRPOS; i++)
- if (cylbp[i] > 0)
- break;
- if (i == NRPOS)
- for (i = 0; i < pos; i++)
- if (cylbp[i] > 0)
- break;
- if (cylbp[i] > 0) {
- /*
- * found a rotational position, now find the actual
- * block. A panic if none is actually there.
- */
- pos = cylno % fs->fs_cpc;
- bno = (cylno - pos) * fs->fs_spc / NSPB(fs);
- if (fs->fs_postbl[pos][i] == -1)
- panic("alloccgblk: cyl groups corrupted");
- for (i = fs->fs_postbl[pos][i];; ) {
- if (isblock(fs, cgp->cg_free, bno + i)) {
- bno = (bno + i) * fs->fs_frag;
- goto gotit;
- }
- delta = fs->fs_rotbl[i];
- if (delta <= 0 || delta > MAXBPC - i)
- break;
- i += delta;
- }
- panic("alloccgblk: can't find blk in cyl");
- }
-norot:
- /*
- * no blocks in the requested cylinder, so take next
- * available one in this cylinder group.
- */
- bno = mapsearch(fs, cgp, bpref, fs->fs_frag);
- if (bno == 0)
- return (NULL);
- cgp->cg_rotor = bno;
-gotit:
- clrblock(fs, cgp->cg_free, bno/fs->fs_frag);
- cgp->cg_cs.cs_nbfree--;
- fs->fs_cstotal.cs_nbfree--;
- fs->fs_cs(fs, cgp->cg_cgx).cs_nbfree--;
- cylno = cbtocylno(fs, bno);
- cgp->cg_b[cylno][cbtorpos(fs, bno)]--;
- cgp->cg_btot[cylno]--;
- fs->fs_fmod++;
- return (cgp->cg_cgx * fs->fs_fpg + bno);
-}
-