/* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)ffs_subr.c 8.5 (Berkeley) 3/21/95 * $FreeBSD: src/sys/ufs/ffs/ffs_subr.c,v 1.25 1999/12/29 04:55:04 peter Exp $ * $DragonFly: src/sys/vfs/ufs/ffs_subr.c,v 1.12 2006/04/27 23:28:37 dillon Exp $ */ #include #ifndef _KERNEL #include "dinode.h" #include "fs.h" #else #include "opt_ddb.h" #include #include #include #include #include #include "quota.h" #include "inode.h" #include "fs.h" #include "ffs_extern.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(struct vnode *vp, off_t offset, char **res, struct buf **bpp) { struct inode *ip; struct fs *fs; struct buf *bp; ufs_daddr_t lbn; int bsize, error; ip = VTOI(vp); fs = ip->i_fs; lbn = lblkno(fs, offset); bsize = blksize(fs, ip, lbn); *bpp = NULL; error = bread(vp, lblktodoff(fs, lbn), bsize, &bp); if (error) { brelse(bp); return (error); } if (res) *res = (char *)bp->b_data + blkoff(fs, offset); *bpp = bp; return (0); } #endif /* * Update the frsum fields to reflect addition or deletion * of some frags. */ void ffs_fragacct(struct fs *fs, int fragmap, int32_t fraglist[], int cnt) { int inblk; int field, subfield; int siz, pos; /* * inblk represents a bitmap of fragment sizes which may be * contained in the data 'fragmap'. e.g. if a fragment of size * 1 is available, bit 0 would be set. inblk is shifted left * by one so we do not have to calculate (1 << (siz - 1)). * * fragment represents the data pattern we are trying to decipher, * we shift it left by one to align it with the 'around' and 'inside' * masks. * * around represents the bits around the subfield and is a mask. * inside represents what we must match within the mask, it is * basically the mask with the first and last bit set to 0, allowing * us to represent a whole fragment. * * When we find a match we bump our position by the size of the * matching fragment, then bump the position again: * * 010101010 fragmap (shifted left by 1) * 111 around mask * 010 inside mask * 111 (shifted by siz) * 010 * 111 (shifted again) * 010 */ 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; } } } /* * block operations * * check if a block is available */ int ffs_isblock(struct fs *fs, unsigned char *cp, ufs_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"); } } /* * check if a block is free */ int ffs_isfreeblock(struct fs *fs, unsigned char *cp, ufs_daddr_t h) { switch ((int)fs->fs_frag) { case 8: return (cp[h] == 0); case 4: return ((cp[h >> 1] & (0x0f << ((h & 0x1) << 2))) == 0); case 2: return ((cp[h >> 2] & (0x03 << ((h & 0x3) << 1))) == 0); case 1: return ((cp[h >> 3] & (0x01 << (h & 0x7))) == 0); default: panic("ffs_isfreeblock"); } } /* * take a block out of the map */ void ffs_clrblock(struct fs *fs, u_char *cp, ufs_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(struct fs *fs, unsigned char *cp, ufs_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"); } }