[unix-history] / usr / src / sys / ufs / ffs / ffs_subr.c

/*
* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*
*      @(#)ffs_subr.c  7.26 (Berkeley) %G%
*/

#include <sys/param.h>
#include <ufs/ffs/fs.h>

#ifdef KERNEL
#include <sys/systm.h>
#include <sys/vnode.h>
#include <ufs/ffs/ffs_extern.h>
#include <sys/buf.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>

/*
* Return buffer with the contents of block "offset" from the beginning of
* directory "ip".  If "res" is non-zero, fill it in with a pointer to the
* remaining space in the directory.
*/
int
ffs_blkatoff(ap)
       struct vop_blkatoff_args /* {
               struct vnode *a_vp;
               off_t a_offset;
               char **a_res;
               struct buf **a_bpp;
       } */ *ap;
{
       struct inode *ip;
       register struct fs *fs;
       struct buf *bp;
       daddr_t lbn;
       int bsize, error;

       ip = VTOI(ap->a_vp);
       fs = ip->i_fs;
       lbn = lblkno(fs, ap->a_offset);
       bsize = blksize(fs, ip, lbn);

       *ap->a_bpp = NULL;
       if (error = bread(ap->a_vp, lbn, bsize, NOCRED, &bp)) {
               brelse(bp);
               return (error);
       }
       if (ap->a_res)
               *ap->a_res = bp->b_un.b_addr + blkoff(fs, ap->a_offset);
       *ap->a_bpp = bp;
       return (0);
}
#endif

/*
* Update the frsum fields to reflect addition or deletion 
* of some frags.
*/
void
ffs_fragacct(fs, fragmap, fraglist, cnt)
       struct fs *fs;
       int fragmap;
       long fraglist[];
       int cnt;
{
       int inblk;
       register int field, subfield;
       register int siz, pos;

       inblk = (int)(fragtbl[fs->fs_frag][fragmap]) << 1;
       fragmap <<= 1;
       for (siz = 1; siz < fs->fs_frag; siz++) {
               if ((inblk & (1 << (siz + (fs->fs_frag % NBBY)))) == 0)
                       continue;
               field = around[siz];
               subfield = inside[siz];
               for (pos = siz; pos <= fs->fs_frag; pos++) {
                       if ((fragmap & field) == subfield) {
                               fraglist[siz] += cnt;
                               pos += siz;
                               field <<= siz;
                               subfield <<= siz;
                       }
                       field <<= 1;
                       subfield <<= 1;
               }
       }
}

#if defined(KERNEL) && defined(DIAGNOSTIC)
void
ffs_checkoverlap(bp, ip)
       struct buf *bp;
       struct inode *ip;
{
       register struct buf *ebp, *ep;
       register daddr_t start, last;
       struct vnode *vp;

       ebp = &buf[nbuf];
       start = bp->b_blkno;
       last = start + btodb(bp->b_bcount) - 1;
       for (ep = buf; ep < ebp; ep++) {
               if (ep == bp || (ep->b_flags & B_INVAL) ||
                   ep->b_vp == NULLVP)
                       continue;
               if (VOP_BMAP(ep->b_vp, (daddr_t)0, &vp, (daddr_t)0))
                       continue;
               if (vp != ip->i_devvp)
                       continue;
               /* look for overlap */
               if (ep->b_bcount == 0 || ep->b_blkno > last ||
                   ep->b_blkno + btodb(ep->b_bcount) <= start)
                       continue;
               vprint("Disk overlap", vp);
               (void)printf("\tstart %d, end %d overlap start %d, end %d\n",
                       start, last, ep->b_blkno,
                       ep->b_blkno + btodb(ep->b_bcount) - 1);
               panic("Disk buffer overlap");
       }
}
#endif /* DIAGNOSTIC */

/*
* block operations
*
* check if a block is available
*/
int
ffs_isblock(fs, cp, h)
       struct fs *fs;
       unsigned char *cp;
       daddr_t h;
{
       unsigned char mask;

       switch ((int)fs->fs_frag) {
       case 8:
               return (cp[h] == 0xff);
       case 4:
               mask = 0x0f << ((h & 0x1) << 2);
               return ((cp[h >> 1] & mask) == mask);
       case 2:
               mask = 0x03 << ((h & 0x3) << 1);
               return ((cp[h >> 2] & mask) == mask);
       case 1:
               mask = 0x01 << (h & 0x7);
               return ((cp[h >> 3] & mask) == mask);
       default:
               panic("ffs_isblock");
       }
}

/*
* take a block out of the map
*/
void
ffs_clrblock(fs, cp, h)
       struct fs *fs;
       u_char *cp;
       daddr_t h;
{

       switch ((int)fs->fs_frag) {
       case 8:
               cp[h] = 0;
               return;
       case 4:
               cp[h >> 1] &= ~(0x0f << ((h & 0x1) << 2));
               return;
       case 2:
               cp[h >> 2] &= ~(0x03 << ((h & 0x3) << 1));
               return;
       case 1:
               cp[h >> 3] &= ~(0x01 << (h & 0x7));
               return;
       default:
               panic("ffs_clrblock");
       }
}

/*
* put a block into the map
*/
void
ffs_setblock(fs, cp, h)
       struct fs *fs;
       unsigned char *cp;
       daddr_t h;
{

       switch ((int)fs->fs_frag) {

       case 8:
               cp[h] = 0xff;
               return;
       case 4:
               cp[h >> 1] |= (0x0f << ((h & 0x1) << 2));
               return;
       case 2:
               cp[h >> 2] |= (0x03 << ((h & 0x3) << 1));
               return;
       case 1:
               cp[h >> 3] |= (0x01 << (h & 0x7));
               return;
       default:
               panic("ffs_setblock");
       }
}