-/* lfs_alloc.c 2.4 82/04/19 */
-
-#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/dir.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;
- 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);
- }
- brealloc(bp, 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) {
- 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);
- bcopy(obp->b_un.b_addr, bp->b_un.b_addr, osize);
- blkclr(bp->b_un.b_addr + osize, nsize - osize);
- brelse(obp);
- fre(ip, bprev, (off_t)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);
-}
-