/* $NetBSD: ffs_alloc.c,v 1.3 1994/07/04 21:06:07 mycroft Exp $ */ /* * 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_alloc.c 8.8 (Berkeley) 2/21/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include extern u_long nextgennumber; static daddr_t ffs_alloccg __P((struct inode *, int, daddr_t, int)); static daddr_t ffs_alloccgblk __P((struct fs *, struct cg *, daddr_t)); static daddr_t ffs_clusteralloc __P((struct inode *, int, daddr_t, int)); static ino_t ffs_dirpref __P((struct fs *)); static daddr_t ffs_fragextend __P((struct inode *, int, long, int, int)); static void ffs_fserr __P((struct fs *, u_int, char *)); static u_long ffs_hashalloc __P((struct inode *, int, long, int, u_long (*)())); static ino_t ffs_nodealloccg __P((struct inode *, int, daddr_t, int)); static daddr_t ffs_mapsearch __P((struct fs *, struct cg *, daddr_t, int)); /* * 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. */ ffs_alloc(ip, lbn, bpref, size, cred, bnp) register struct inode *ip; daddr_t lbn, bpref; int size; struct ucred *cred; daddr_t *bnp; { register struct fs *fs; daddr_t bno; int cg, error; *bnp = 0; fs = ip->i_fs; #ifdef DIAGNOSTIC if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) { printf("dev = 0x%x, bsize = %d, size = %d, fs = %s\n", ip->i_dev, fs->fs_bsize, size, fs->fs_fsmnt); panic("ffs_alloc: bad size"); } if (cred == NOCRED) panic("ffs_alloc: missing credential\n"); #endif /* DIAGNOSTIC */ if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0) goto nospace; if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0) goto nospace; #ifdef QUOTA if (error = chkdq(ip, (long)btodb(size), cred, 0)) return (error); #endif if (bpref >= fs->fs_size) bpref = 0; if (bpref == 0) cg = ino_to_cg(fs, ip->i_number); else cg = dtog(fs, bpref); bno = (daddr_t)ffs_hashalloc(ip, cg, (long)bpref, size, (u_long (*)())ffs_alloccg); if (bno > 0) { ip->i_blocks += btodb(size); ip->i_flag |= IN_CHANGE | IN_UPDATE; *bnp = bno; return (0); } #ifdef QUOTA /* * Restore user's disk quota because allocation failed. */ (void) chkdq(ip, (long)-btodb(size), cred, FORCE); #endif nospace: ffs_fserr(fs, cred->cr_uid, "file system full"); uprintf("\n%s: write failed, file system is full\n", fs->fs_fsmnt); return (ENOSPC); } /* * 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. */ ffs_realloccg(ip, lbprev, bpref, osize, nsize, cred, bpp) register struct inode *ip; daddr_t lbprev; daddr_t bpref; int osize, nsize; struct ucred *cred; struct buf **bpp; { register struct fs *fs; struct buf *bp; int cg, request, error; daddr_t bprev, bno; *bpp = 0; fs = ip->i_fs; #ifdef DIAGNOSTIC if ((u_int)osize > fs->fs_bsize || fragoff(fs, osize) != 0 || (u_int)nsize > fs->fs_bsize || fragoff(fs, nsize) != 0) { printf( "dev = 0x%x, bsize = %d, osize = %d, nsize = %d, fs = %s\n", ip->i_dev, fs->fs_bsize, osize, nsize, fs->fs_fsmnt); panic("ffs_realloccg: bad size"); } if (cred == NOCRED) panic("ffs_realloccg: missing credential\n"); #endif /* DIAGNOSTIC */ if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0) goto nospace; if ((bprev = ip->i_db[lbprev]) == 0) { printf("dev = 0x%x, bsize = %d, bprev = %d, fs = %s\n", ip->i_dev, fs->fs_bsize, bprev, fs->fs_fsmnt); panic("ffs_realloccg: bad bprev"); } /* * Allocate the extra space in the buffer. */ if (error = bread(ITOV(ip), lbprev, osize, NOCRED, &bp)) { brelse(bp); return (error); } #ifdef QUOTA if (error = chkdq(ip, (long)btodb(nsize - osize), cred, 0)) { brelse(bp); return (error); } #endif /* * Check for extension in the existing location. */ cg = dtog(fs, bprev); if (bno = ffs_fragextend(ip, cg, (long)bprev, osize, nsize)) { if (bp->b_blkno != fsbtodb(fs, bno)) panic("bad blockno"); ip->i_blocks += btodb(nsize - osize); ip->i_flag |= IN_CHANGE | IN_UPDATE; allocbuf(bp, nsize); bp->b_flags |= B_DONE; bzero((char *)bp->b_data + osize, (u_int)nsize - osize); *bpp = bp; return (0); } /* * Allocate a new disk location. */ if (bpref >= fs->fs_size) bpref = 0; switch ((int)fs->fs_optim) { case FS_OPTSPACE: /* * Allocate an exact sized fragment. Although this makes * best use of space, we will waste time relocating it if * the file continues to grow. If the fragmentation is * less than half of the minimum free reserve, we choose * to begin optimizing for time. */ request = nsize; if (fs->fs_minfree < 5 || fs->fs_cstotal.cs_nffree > fs->fs_dsize * fs->fs_minfree / (2 * 100)) break; log(LOG_NOTICE, "%s: optimization changed from SPACE to TIME\n", fs->fs_fsmnt); fs->fs_optim = FS_OPTTIME; break; case FS_OPTTIME: /* * At this point we have discovered a file that is trying to * grow a small fragment to a larger fragment. To save time, * we allocate a full sized block, then free the unused portion. * If the file continues to grow, the `ffs_fragextend' call * above will be able to grow it in place without further * copying. If aberrant programs cause disk fragmentation to * grow within 2% of the free reserve, we choose to begin * optimizing for space. */ request = fs->fs_bsize; if (fs->fs_cstotal.cs_nffree < fs->fs_dsize * (fs->fs_minfree - 2) / 100) break; log(LOG_NOTICE, "%s: optimization changed from TIME to SPACE\n", fs->fs_fsmnt); fs->fs_optim = FS_OPTSPACE; break; default: printf("dev = 0x%x, optim = %d, fs = %s\n", ip->i_dev, fs->fs_optim, fs->fs_fsmnt); panic("ffs_realloccg: bad optim"); /* NOTREACHED */ } bno = (daddr_t)ffs_hashalloc(ip, cg, (long)bpref, request, (u_long (*)())ffs_alloccg); if (bno > 0) { bp->b_blkno = fsbtodb(fs, bno); (void) vnode_pager_uncache(ITOV(ip)); ffs_blkfree(ip, bprev, (long)osize); if (nsize < request) ffs_blkfree(ip, bno + numfrags(fs, nsize), (long)(request - nsize)); ip->i_blocks += btodb(nsize - osize); ip->i_flag |= IN_CHANGE | IN_UPDATE; allocbuf(bp, nsize); bp->b_flags |= B_DONE; bzero((char *)bp->b_data + osize, (u_int)nsize - osize); *bpp = bp; return (0); } #ifdef QUOTA /* * Restore user's disk quota because allocation failed. */ (void) chkdq(ip, (long)-btodb(nsize - osize), cred, FORCE); #endif brelse(bp); nospace: /* * no space available */ ffs_fserr(fs, cred->cr_uid, "file system full"); uprintf("\n%s: write failed, file system is full\n", fs->fs_fsmnt); return (ENOSPC); } /* * Reallocate a sequence of blocks into a contiguous sequence of blocks. * * The vnode and an array of buffer pointers for a range of sequential * logical blocks to be made contiguous is given. The allocator attempts * to find a range of sequential blocks starting as close as possible to * an fs_rotdelay offset from the end of the allocation for the logical * block immediately preceeding the current range. If successful, the * physical block numbers in the buffer pointers and in the inode are * changed to reflect the new allocation. If unsuccessful, the allocation * is left unchanged. The success in doing the reallocation is returned. * Note that the error return is not reflected back to the user. Rather * the previous block allocation will be used. */ #ifdef DEBUG #include int doasyncfree = 1; struct ctldebug debug14 = { "doasyncfree", &doasyncfree }; #else #define doasyncfree 1 #endif int ffs_reallocblks(ap) struct vop_reallocblks_args /* { struct vnode *a_vp; struct cluster_save *a_buflist; } */ *ap; { struct fs *fs; struct inode *ip; struct vnode *vp; struct buf *sbp, *ebp; daddr_t *bap, *sbap, *ebap; struct cluster_save *buflist; daddr_t start_lbn, end_lbn, soff, eoff, newblk, blkno; struct indir start_ap[NIADDR + 1], end_ap[NIADDR + 1], *idp; int i, len, start_lvl, end_lvl, pref, ssize; vp = ap->a_vp; ip = VTOI(vp); fs = ip->i_fs; if (fs->fs_contigsumsize <= 0) return (ENOSPC); buflist = ap->a_buflist; len = buflist->bs_nchildren; start_lbn = buflist->bs_children[0]->b_lblkno; end_lbn = start_lbn + len - 1; #ifdef DIAGNOSTIC for (i = 1; i < len; i++) if (buflist->bs_children[i]->b_lblkno != start_lbn + i) panic("ffs_reallocblks: non-cluster"); #endif /* * If the latest allocation is in a new cylinder group, assume that * the filesystem has decided to move and do not force it back to * the previous cylinder group. */ if (dtog(fs, dbtofsb(fs, buflist->bs_children[0]->b_blkno)) != dtog(fs, dbtofsb(fs, buflist->bs_children[len - 1]->b_blkno))) return (ENOSPC); if (ufs_getlbns(vp, start_lbn, start_ap, &start_lvl) || ufs_getlbns(vp, end_lbn, end_ap, &end_lvl)) return (ENOSPC); /* * Get the starting offset and block map for the first block. */ if (start_lvl == 0) { sbap = &ip->i_db[0]; soff = start_lbn; } else { idp = &start_ap[start_lvl - 1]; if (bread(vp, idp->in_lbn, (int)fs->fs_bsize, NOCRED, &sbp)) { brelse(sbp); return (ENOSPC); } sbap = (daddr_t *)sbp->b_data; soff = idp->in_off; } /* * Find the preferred location for the cluster. */ pref = ffs_blkpref(ip, start_lbn, soff, sbap); /* * If the block range spans two block maps, get the second map. */ if (end_lvl == 0 || (idp = &end_ap[end_lvl - 1])->in_off + 1 >= len) { ssize = len; } else { #ifdef DIAGNOSTIC if (start_ap[start_lvl-1].in_lbn == idp->in_lbn) panic("ffs_reallocblk: start == end"); #endif ssize = len - (idp->in_off + 1); if (bread(vp, idp->in_lbn, (int)fs->fs_bsize, NOCRED, &ebp)) goto fail; ebap = (daddr_t *)ebp->b_data; } /* * Search the block map looking for an allocation of the desired size. */ if ((newblk = (daddr_t)ffs_hashalloc(ip, dtog(fs, pref), (long)pref, len, (u_long (*)())ffs_clusteralloc)) == 0) goto fail; /* * We have found a new contiguous block. * * First we have to replace the old block pointers with the new * block pointers in the inode and indirect blocks associated * with the file. */ blkno = newblk; for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->fs_frag) { if (i == ssize) bap = ebap; #ifdef DIAGNOSTIC if (buflist->bs_children[i]->b_blkno != fsbtodb(fs, *bap)) panic("ffs_reallocblks: alloc mismatch"); #endif *bap++ = blkno; } /* * Next we must write out the modified inode and indirect blocks. * For strict correctness, the writes should be synchronous since * the old block values may have been written to disk. In practise * they are almost never written, but if we are concerned about * strict correctness, the `doasyncfree' flag should be set to zero. * * The test on `doasyncfree' should be changed to test a flag * that shows whether the associated buffers and inodes have * been written. The flag should be set when the cluster is * started and cleared whenever the buffer or inode is flushed. * We can then check below to see if it is set, and do the * synchronous write only when it has been cleared. */ if (sbap != &ip->i_db[0]) { if (doasyncfree) bdwrite(sbp); else bwrite(sbp); } else { ip->i_flag |= IN_CHANGE | IN_UPDATE; if (!doasyncfree) VOP_UPDATE(vp, &time, &time, MNT_WAIT); } if (ssize < len) if (doasyncfree) bdwrite(ebp); else bwrite(ebp); /* * Last, free the old blocks and assign the new blocks to the buffers. */ for (blkno = newblk, i = 0; i < len; i++, blkno += fs->fs_frag) { ffs_blkfree(ip, dbtofsb(fs, buflist->bs_children[i]->b_blkno), fs->fs_bsize); buflist->bs_children[i]->b_blkno = fsbtodb(fs, blkno); } return (0); fail: if (ssize < len) brelse(ebp); if (sbap != &ip->i_db[0]) brelse(sbp); return (ENOSPC); } /* * Allocate an inode in the file system. * * If allocating a directory, use ffs_dirpref to select the inode. * If allocating in a directory, the following hierarchy is followed: * 1) allocate the preferred 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. */ ffs_valloc(ap) struct vop_valloc_args /* { struct vnode *a_pvp; int a_mode; struct ucred *a_cred; struct vnode **a_vpp; } */ *ap; { register struct vnode *pvp = ap->a_pvp; register struct inode *pip; register struct fs *fs; register struct inode *ip; mode_t mode = ap->a_mode; ino_t ino, ipref; int cg, error; *ap->a_vpp = NULL; pip = VTOI(pvp); fs = pip->i_fs; if (fs->fs_cstotal.cs_nifree == 0) goto noinodes; if ((mode & IFMT) == IFDIR) ipref = ffs_dirpref(fs); else ipref = pip->i_number; if (ipref >= fs->fs_ncg * fs->fs_ipg) ipref = 0; cg = ino_to_cg(fs, ipref); ino = (ino_t)ffs_hashalloc(pip, cg, (long)ipref, mode, ffs_nodealloccg); if (ino == 0) goto noinodes; error = VFS_VGET(pvp->v_mount, ino, ap->a_vpp); if (error) { VOP_VFREE(pvp, ino, mode); return (error); } ip = VTOI(*ap->a_vpp); if (ip->i_mode) { printf("mode = 0%o, inum = %d, fs = %s\n", ip->i_mode, ip->i_number, fs->fs_fsmnt); panic("ffs_valloc: dup alloc"); } if (ip->i_blocks) { /* XXX */ printf("free inode %s/%d had %d blocks\n", fs->fs_fsmnt, ino, ip->i_blocks); ip->i_blocks = 0; } ip->i_flags = 0; /* * Set up a new generation number for this inode. */ if (++nextgennumber < (u_long)time.tv_sec) nextgennumber = time.tv_sec; ip->i_gen = nextgennumber; return (0); noinodes: ffs_fserr(fs, ap->a_cred->cr_uid, "out of inodes"); uprintf("\n%s: create/symlink failed, no inodes free\n", fs->fs_fsmnt); return (ENOSPC); } /* * 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. */ static ino_t ffs_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 ((ino_t)(fs->fs_ipg * mincg)); } /* * Select the desired position for the next block in a file. The file is * logically divided into sections. The first section is composed of the * direct blocks. Each additional section contains fs_maxbpg blocks. * * If no blocks have been allocated in the first section, the policy is to * request a block in the same cylinder group as the inode that describes * the file. If no blocks have been allocated in any other section, the * policy is to place the section in a cylinder group with a greater than * average number of free blocks. An appropriate cylinder group is found * by using a rotor that sweeps the cylinder groups. When a new group of * blocks is needed, the sweep begins in the cylinder group following the * cylinder group from which the previous allocation was made. The sweep * continues until a cylinder group with greater than the average number * of free blocks is found. If the allocation is for the first block in an * indirect block, the information on the previous allocation is unavailable; * here a best guess is made based upon the logical block number being * allocated. * * If a section is already partially allocated, the policy is to * contiguously allocate fs_maxcontig blocks. The end of one of these * contiguous blocks and the beginning of the next is physically separated * so that the disk head will be in transit between them for at least * fs_rotdelay milliseconds. This is to allow time for the processor to * schedule another I/O transfer. */ daddr_t ffs_blkpref(ip, lbn, indx, bap) struct inode *ip; daddr_t lbn; int indx; daddr_t *bap; { register struct fs *fs; register int cg; int avgbfree, startcg; daddr_t nextblk; fs = ip->i_fs; if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) { if (lbn < NDADDR) { cg = ino_to_cg(fs, ip->i_number); return (fs->fs_fpg * cg + fs->fs_frag); } /* * Find a cylinder with greater than average number of * unused data blocks. */ if (indx == 0 || bap[indx - 1] == 0) startcg = ino_to_cg(fs, ip->i_number) + lbn / fs->fs_maxbpg; else startcg = dtog(fs, bap[indx - 1]) + 1; startcg %= fs->fs_ncg; avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg; for (cg = startcg; 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 <= startcg; cg++) if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) { fs->fs_cgrotor = cg; return (fs->fs_fpg * cg + fs->fs_frag); } return (NULL); } /* * One or more previous blocks have been laid out. If less * than fs_maxcontig previous blocks are contiguous, the * next block is requested contiguously, otherwise it is * requested rotationally delayed by fs_rotdelay milliseconds. */ nextblk = bap[indx - 1] + fs->fs_frag; if (indx < fs->fs_maxcontig || bap[indx - fs->fs_maxcontig] + blkstofrags(fs, fs->fs_maxcontig) != nextblk) return (nextblk); if (fs->fs_rotdelay != 0) /* * 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 block. */ nextblk += roundup(fs->fs_rotdelay * fs->fs_rps * fs->fs_nsect / (NSPF(fs) * 1000), fs->fs_frag); return (nextblk); } /* * 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*/ static u_long ffs_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 * Note that we start at i == 2, since 0 was checked initially, * and 1 is always checked in the quadratic rehash. */ cg = (icg + 2) % fs->fs_ncg; for (i = 2; 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. */ static daddr_t ffs_fragextend(ip, cg, bprev, osize, nsize) struct inode *ip; int cg; long bprev; int osize, nsize; { register struct fs *fs; register struct cg *cgp; struct buf *bp; long bno; int frags, bbase; int i, error; fs = ip->i_fs; if (fs->fs_cs(fs, cg).cs_nffree < numfrags(fs, nsize - osize)) return (NULL); frags = numfrags(fs, nsize); bbase = fragnum(fs, bprev); if (bbase > fragnum(fs, (bprev + frags - 1))) { /* cannot extend across a block boundary */ return (NULL); } error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp); if (error) { brelse(bp); return (NULL); } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp)) { brelse(bp); return (NULL); } cgp->cg_time = time.tv_sec; bno = dtogd(fs, bprev); for (i = numfrags(fs, osize); i < frags; i++) if (isclr(cg_blksfree(cgp), 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(cg_blksfree(cgp), 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(cg_blksfree(cgp), bno + i); cgp->cg_cs.cs_nffree--; fs->fs_cstotal.cs_nffree--; fs->fs_cs(fs, cg).cs_nffree--; } fs->fs_fmod = 1; bdwrite(bp); return (bprev); } /* * Determine whether a block can be allocated. * * Check to see if a block of the appropriate size is available, * and if it is, allocate it. */ static daddr_t ffs_alloccg(ip, cg, bpref, size) struct inode *ip; int cg; daddr_t bpref; int size; { register struct fs *fs; register struct cg *cgp; struct buf *bp; register int i; int error, bno, frags, allocsiz; fs = ip->i_fs; if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize) return (NULL); error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp); if (error) { brelse(bp); return (NULL); } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp) || (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize)) { brelse(bp); return (NULL); } cgp->cg_time = time.tv_sec; if (size == fs->fs_bsize) { bno = ffs_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 = ffs_alloccgblk(fs, cgp, bpref); bpref = dtogd(fs, bno); for (i = frags; i < fs->fs_frag; i++) setbit(cg_blksfree(cgp), 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; fs->fs_fmod = 1; cgp->cg_frsum[i]++; bdwrite(bp); return (bno); } bno = ffs_mapsearch(fs, cgp, bpref, allocsiz); if (bno < 0) { brelse(bp); return (NULL); } for (i = 0; i < frags; i++) clrbit(cg_blksfree(cgp), bno + i); cgp->cg_cs.cs_nffree -= frags; fs->fs_cstotal.cs_nffree -= frags; fs->fs_cs(fs, cg).cs_nffree -= frags; fs->fs_fmod = 1; 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. */ static daddr_t ffs_alloccgblk(fs, cgp, bpref) register struct fs *fs; register struct cg *cgp; daddr_t bpref; { daddr_t bno, blkno; int cylno, pos, delta; short *cylbp; register int i; if (bpref == 0 || dtog(fs, bpref) != cgp->cg_cgx) { bpref = cgp->cg_rotor; goto norot; } bpref = blknum(fs, bpref); bpref = dtogd(fs, bpref); /* * if the requested block is available, use it */ if (ffs_isblock(fs, cg_blksfree(cgp), fragstoblks(fs, bpref))) { bno = bpref; goto gotit; } /* * check for a block available on the same cylinder */ cylno = cbtocylno(fs, bpref); if (cg_blktot(cgp)[cylno] == 0) goto norot; if (fs->fs_cpc == 0) { /* * Block layout information is not available. * Leaving bpref unchanged means we take the * next available free block following the one * we just allocated. Hopefully this will at * least hit a track cache on drives of unknown * geometry (e.g. SCSI). */ goto norot; } /* * check the summary information to see if a block is * available in the requested cylinder starting at the * requested rotational position and proceeding around. */ cylbp = cg_blks(fs, cgp, cylno); pos = cbtorpos(fs, bpref); for (i = pos; i < fs->fs_nrpos; i++) if (cylbp[i] > 0) break; if (i == fs->fs_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_postbl(fs, pos)[i] == -1) { printf("pos = %d, i = %d, fs = %s\n", pos, i, fs->fs_fsmnt); panic("ffs_alloccgblk: cyl groups corrupted"); } for (i = fs_postbl(fs, pos)[i];; ) { if (ffs_isblock(fs, cg_blksfree(cgp), bno + i)) { bno = blkstofrags(fs, (bno + i)); goto gotit; } delta = fs_rotbl(fs)[i]; if (delta <= 0 || delta + i > fragstoblks(fs, fs->fs_fpg)) break; i += delta; } printf("pos = %d, i = %d, fs = %s\n", pos, i, fs->fs_fsmnt); panic("ffs_alloccgblk: can't find blk in cyl"); } norot: /* * no blocks in the requested cylinder, so take next * available one in this cylinder group. */ bno = ffs_mapsearch(fs, cgp, bpref, (int)fs->fs_frag); if (bno < 0) return (NULL); cgp->cg_rotor = bno; gotit: blkno = fragstoblks(fs, bno); ffs_clrblock(fs, cg_blksfree(cgp), (long)blkno); ffs_clusteracct(fs, cgp, blkno, -1); cgp->cg_cs.cs_nbfree--; fs->fs_cstotal.cs_nbfree--; fs->fs_cs(fs, cgp->cg_cgx).cs_nbfree--; cylno = cbtocylno(fs, bno); cg_blks(fs, cgp, cylno)[cbtorpos(fs, bno)]--; cg_blktot(cgp)[cylno]--; fs->fs_fmod = 1; return (cgp->cg_cgx * fs->fs_fpg + bno); } /* * Determine whether a cluster can be allocated. * * We do not currently check for optimal rotational layout if there * are multiple choices in the same cylinder group. Instead we just * take the first one that we find following bpref. */ static daddr_t ffs_clusteralloc(ip, cg, bpref, len) struct inode *ip; int cg; daddr_t bpref; int len; { register struct fs *fs; register struct cg *cgp; struct buf *bp; int i, run, bno, bit, map; u_char *mapp; fs = ip->i_fs; if (fs->fs_cs(fs, cg).cs_nbfree < len) return (NULL); if (bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp)) goto fail; cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp)) goto fail; /* * Check to see if a cluster of the needed size (or bigger) is * available in this cylinder group. */ for (i = len; i <= fs->fs_contigsumsize; i++) if (cg_clustersum(cgp)[i] > 0) break; if (i > fs->fs_contigsumsize) goto fail; /* * Search the cluster map to find a big enough cluster. * We take the first one that we find, even if it is larger * than we need as we prefer to get one close to the previous * block allocation. We do not search before the current * preference point as we do not want to allocate a block * that is allocated before the previous one (as we will * then have to wait for another pass of the elevator * algorithm before it will be read). We prefer to fail and * be recalled to try an allocation in the next cylinder group. */ if (dtog(fs, bpref) != cg) bpref = 0; else bpref = fragstoblks(fs, dtogd(fs, blknum(fs, bpref))); mapp = &cg_clustersfree(cgp)[bpref / NBBY]; map = *mapp++; bit = 1 << (bpref % NBBY); for (run = 0, i = bpref; i < cgp->cg_nclusterblks; i++) { if ((map & bit) == 0) { run = 0; } else { run++; if (run == len) break; } if ((i & (NBBY - 1)) != (NBBY - 1)) { bit <<= 1; } else { map = *mapp++; bit = 1; } } if (i == cgp->cg_nclusterblks) goto fail; /* * Allocate the cluster that we have found. */ bno = cg * fs->fs_fpg + blkstofrags(fs, i - run + 1); len = blkstofrags(fs, len); for (i = 0; i < len; i += fs->fs_frag) if (ffs_alloccgblk(fs, cgp, bno + i) != bno + i) panic("ffs_clusteralloc: lost block"); brelse(bp); return (bno); fail: brelse(bp); return (0); } /* * Determine whether an inode can be allocated. * * Check to see if an inode is available, and if it is, * allocate it using the following policy: * 1) allocate the requested inode. * 2) allocate the next available inode after the requested * inode in the specified cylinder group. */ static ino_t ffs_nodealloccg(ip, cg, ipref, mode) struct inode *ip; int cg; daddr_t ipref; int mode; { register struct fs *fs; register struct cg *cgp; struct buf *bp; int error, start, len, loc, map, i; fs = ip->i_fs; if (fs->fs_cs(fs, cg).cs_nifree == 0) return (NULL); error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp); if (error) { brelse(bp); return (NULL); } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp) || cgp->cg_cs.cs_nifree == 0) { brelse(bp); return (NULL); } cgp->cg_time = time.tv_sec; if (ipref) { ipref %= fs->fs_ipg; if (isclr(cg_inosused(cgp), ipref)) goto gotit; } start = cgp->cg_irotor / NBBY; len = howmany(fs->fs_ipg - cgp->cg_irotor, NBBY); loc = skpc(0xff, len, &cg_inosused(cgp)[start]); if (loc == 0) { len = start + 1; start = 0; loc = skpc(0xff, len, &cg_inosused(cgp)[0]); if (loc == 0) { printf("cg = %d, irotor = %d, fs = %s\n", cg, cgp->cg_irotor, fs->fs_fsmnt); panic("ffs_nodealloccg: map corrupted"); /* NOTREACHED */ } } i = start + len - loc; map = cg_inosused(cgp)[i]; ipref = i * NBBY; for (i = 1; i < (1 << NBBY); i <<= 1, ipref++) { if ((map & i) == 0) { cgp->cg_irotor = ipref; goto gotit; } } printf("fs = %s\n", fs->fs_fsmnt); panic("ffs_nodealloccg: block not in map"); /* NOTREACHED */ gotit: setbit(cg_inosused(cgp), ipref); cgp->cg_cs.cs_nifree--; fs->fs_cstotal.cs_nifree--; fs->fs_cs(fs, cg).cs_nifree--; fs->fs_fmod = 1; if ((mode & IFMT) == IFDIR) { cgp->cg_cs.cs_ndir++; fs->fs_cstotal.cs_ndir++; fs->fs_cs(fs, cg).cs_ndir++; } bdwrite(bp); return (cg * fs->fs_ipg + ipref); } /* * Free a block or fragment. * * The specified block or fragment is placed back in the * free map. If a fragment is deallocated, a possible * block reassembly is checked. */ ffs_blkfree(ip, bno, size) register struct inode *ip; daddr_t bno; long size; { register struct fs *fs; register struct cg *cgp; struct buf *bp; daddr_t blkno; int i, error, cg, blk, frags, bbase; fs = ip->i_fs; if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) { printf("dev = 0x%x, bsize = %d, size = %d, fs = %s\n", ip->i_dev, fs->fs_bsize, size, fs->fs_fsmnt); panic("blkfree: bad size"); } cg = dtog(fs, bno); if ((u_int)bno >= fs->fs_size) { printf("bad block %d, ino %d\n", bno, ip->i_number); ffs_fserr(fs, ip->i_uid, "bad block"); return; } error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp); if (error) { brelse(bp); return; } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp)) { brelse(bp); return; } cgp->cg_time = time.tv_sec; bno = dtogd(fs, bno); if (size == fs->fs_bsize) { blkno = fragstoblks(fs, bno); if (ffs_isblock(fs, cg_blksfree(cgp), blkno)) { printf("dev = 0x%x, block = %d, fs = %s\n", ip->i_dev, bno, fs->fs_fsmnt); panic("blkfree: freeing free block"); } ffs_setblock(fs, cg_blksfree(cgp), blkno); ffs_clusteracct(fs, cgp, blkno, 1); cgp->cg_cs.cs_nbfree++; fs->fs_cstotal.cs_nbfree++; fs->fs_cs(fs, cg).cs_nbfree++; i = cbtocylno(fs, bno); cg_blks(fs, cgp, i)[cbtorpos(fs, bno)]++; cg_blktot(cgp)[i]++; } else { bbase = bno - fragnum(fs, bno); /* * decrement the counts associated with the old frags */ blk = blkmap(fs, cg_blksfree(cgp), bbase); ffs_fragacct(fs, blk, cgp->cg_frsum, -1); /* * deallocate the fragment */ frags = numfrags(fs, size); for (i = 0; i < frags; i++) { if (isset(cg_blksfree(cgp), bno + i)) { printf("dev = 0x%x, block = %d, fs = %s\n", ip->i_dev, bno + i, fs->fs_fsmnt); panic("blkfree: freeing free frag"); } setbit(cg_blksfree(cgp), bno + i); } cgp->cg_cs.cs_nffree += i; fs->fs_cstotal.cs_nffree += i; fs->fs_cs(fs, cg).cs_nffree += i; /* * add back in counts associated with the new frags */ blk = blkmap(fs, cg_blksfree(cgp), bbase); ffs_fragacct(fs, blk, cgp->cg_frsum, 1); /* * if a complete block has been reassembled, account for it */ blkno = fragstoblks(fs, bbase); if (ffs_isblock(fs, cg_blksfree(cgp), blkno)) { cgp->cg_cs.cs_nffree -= fs->fs_frag; fs->fs_cstotal.cs_nffree -= fs->fs_frag; fs->fs_cs(fs, cg).cs_nffree -= fs->fs_frag; ffs_clusteracct(fs, cgp, blkno, 1); cgp->cg_cs.cs_nbfree++; fs->fs_cstotal.cs_nbfree++; fs->fs_cs(fs, cg).cs_nbfree++; i = cbtocylno(fs, bbase); cg_blks(fs, cgp, i)[cbtorpos(fs, bbase)]++; cg_blktot(cgp)[i]++; } } fs->fs_fmod = 1; bdwrite(bp); } /* * Free an inode. * * The specified inode is placed back in the free map. */ int ffs_vfree(ap) struct vop_vfree_args /* { struct vnode *a_pvp; ino_t a_ino; int a_mode; } */ *ap; { register struct fs *fs; register struct cg *cgp; register struct inode *pip; ino_t ino = ap->a_ino; struct buf *bp; int error, cg; pip = VTOI(ap->a_pvp); fs = pip->i_fs; if ((u_int)ino >= fs->fs_ipg * fs->fs_ncg) panic("ifree: range: dev = 0x%x, ino = %d, fs = %s\n", pip->i_dev, ino, fs->fs_fsmnt); cg = ino_to_cg(fs, ino); error = bread(pip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), (int)fs->fs_cgsize, NOCRED, &bp); if (error) { brelse(bp); return (0); } cgp = (struct cg *)bp->b_data; if (!cg_chkmagic(cgp)) { brelse(bp); return (0); } cgp->cg_time = time.tv_sec; ino %= fs->fs_ipg; if (isclr(cg_inosused(cgp), ino)) { printf("dev = 0x%x, ino = %d, fs = %s\n", pip->i_dev, ino, fs->fs_fsmnt); if (fs->fs_ronly == 0) panic("ifree: freeing free inode"); } clrbit(cg_inosused(cgp), ino); if (ino < cgp->cg_irotor) cgp->cg_irotor = ino; cgp->cg_cs.cs_nifree++; fs->fs_cstotal.cs_nifree++; fs->fs_cs(fs, cg).cs_nifree++; if ((ap->a_mode & IFMT) == IFDIR) { cgp->cg_cs.cs_ndir--; fs->fs_cstotal.cs_ndir--; fs->fs_cs(fs, cg).cs_ndir--; } fs->fs_fmod = 1; bdwrite(bp); return (0); } /* * Find a block of the specified size in the specified cylinder group. * * It is a panic if a request is made to find a block if none are * available. */ static daddr_t ffs_mapsearch(fs, cgp, bpref, allocsiz) register struct fs *fs; register struct cg *cgp; daddr_t bpref; int allocsiz; { daddr_t bno; int start, len, loc, i; int blk, field, subfield, pos; /* * find the fragment by searching through the free block * map for an appropriate bit pattern */ if (bpref) start = dtogd(fs, bpref) / NBBY; else start = cgp->cg_frotor / NBBY; len = howmany(fs->fs_fpg, NBBY) - start; loc = scanc((u_int)len, (u_char *)&cg_blksfree(cgp)[start], (u_char *)fragtbl[fs->fs_frag], (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); if (loc == 0) { len = start + 1; start = 0; loc = scanc((u_int)len, (u_char *)&cg_blksfree(cgp)[0], (u_char *)fragtbl[fs->fs_frag], (u_char)(1 << (allocsiz - 1 + (fs->fs_frag % NBBY)))); if (loc == 0) { printf("start = %d, len = %d, fs = %s\n", start, len, fs->fs_fsmnt); panic("ffs_alloccg: map corrupted"); /* NOTREACHED */ } } bno = (start + len - loc) * NBBY; cgp->cg_frotor = bno; /* * found the byte in the map * sift through the bits to find the selected frag */ for (i = bno + NBBY; bno < i; bno += fs->fs_frag) { blk = blkmap(fs, cg_blksfree(cgp), bno); blk <<= 1; field = around[allocsiz]; subfield = inside[allocsiz]; for (pos = 0; pos <= fs->fs_frag - allocsiz; pos++) { if ((blk & field) == subfield) return (bno + pos); field <<= 1; subfield <<= 1; } } printf("bno = %d, fs = %s\n", bno, fs->fs_fsmnt); panic("ffs_alloccg: block not in map"); return (-1); } /* * Update the cluster map because of an allocation or free. * * Cnt == 1 means free; cnt == -1 means allocating. */ ffs_clusteracct(fs, cgp, blkno, cnt) struct fs *fs; struct cg *cgp; daddr_t blkno; int cnt; { long *sump; u_char *freemapp, *mapp; int i, start, end, forw, back, map, bit; if (fs->fs_contigsumsize <= 0) return; freemapp = cg_clustersfree(cgp); sump = cg_clustersum(cgp); /* * Allocate or clear the actual block. */ if (cnt > 0) setbit(freemapp, blkno); else clrbit(freemapp, blkno); /* * Find the size of the cluster going forward. */ start = blkno + 1; end = start + fs->fs_contigsumsize; if (end >= cgp->cg_nclusterblks) end = cgp->cg_nclusterblks; mapp = &freemapp[start / NBBY]; map = *mapp++; bit = 1 << (start % NBBY); for (i = start; i < end; i++) { if ((map & bit) == 0) break; if ((i & (NBBY - 1)) != (NBBY - 1)) { bit <<= 1; } else { map = *mapp++; bit = 1; } } forw = i - start; /* * Find the size of the cluster going backward. */ start = blkno - 1; end = start - fs->fs_contigsumsize; if (end < 0) end = -1; mapp = &freemapp[start / NBBY]; map = *mapp--; bit = 1 << (start % NBBY); for (i = start; i > end; i--) { if ((map & bit) == 0) break; if ((i & (NBBY - 1)) != 0) { bit >>= 1; } else { map = *mapp--; bit = 1 << (NBBY - 1); } } back = start - i; /* * Account for old cluster and the possibly new forward and * back clusters. */ i = back + forw + 1; if (i > fs->fs_contigsumsize) i = fs->fs_contigsumsize; sump[i] += cnt; if (back > 0) sump[back] -= cnt; if (forw > 0) sump[forw] -= cnt; } /* * Fserr prints the name of a file system with an error diagnostic. * * The form of the error message is: * fs: error message */ static void ffs_fserr(fs, uid, cp) struct fs *fs; u_int uid; char *cp; { log(LOG_ERR, "uid %d on %s: %s\n", uid, fs->fs_fsmnt, cp); }