diff options
Diffstat (limited to 'sys/gnu/fs/ext2fs/ext2_bmap.c')
-rw-r--r-- | sys/gnu/fs/ext2fs/ext2_bmap.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/sys/gnu/fs/ext2fs/ext2_bmap.c b/sys/gnu/fs/ext2fs/ext2_bmap.c new file mode 100644 index 0000000..bcd838d --- /dev/null +++ b/sys/gnu/fs/ext2fs/ext2_bmap.c @@ -0,0 +1,294 @@ +/* + * Copyright (c) 1989, 1991, 1993 + * The Regents of the University of California. All rights reserved. + * (c) UNIX System Laboratories, Inc. + * All or some portions of this file are derived from material licensed + * to the University of California by American Telephone and Telegraph + * Co. or Unix System Laboratories, Inc. and are reproduced herein with + * the permission of UNIX System Laboratories, Inc. + * + * 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. + * + * @(#)ufs_bmap.c 8.6 (Berkeley) 1/21/94 + */ + +#include <sys/param.h> +#include <sys/buf.h> +#include <sys/proc.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/resourcevar.h> +#include <sys/trace.h> + +#include <miscfs/specfs/specdev.h> + +#include <ufs/ufs/quota.h> +#include <ufs/ufs/inode.h> +#include <ufs/ufs/ufsmount.h> +#include <ufs/ufs/ufs_extern.h> + +/* + * Bmap converts a the logical block number of a file to its physical block + * number on the disk. The conversion is done by using the logical block + * number to index into the array of block pointers described by the dinode. + */ +int +ufs_bmap(ap) + struct vop_bmap_args /* { + struct vnode *a_vp; + daddr_t a_bn; + struct vnode **a_vpp; + daddr_t *a_bnp; + int *a_runp; + } */ *ap; +{ + /* + * Check for underlying vnode requests and ensure that logical + * to physical mapping is requested. + */ + if (ap->a_vpp != NULL) + *ap->a_vpp = VTOI(ap->a_vp)->i_devvp; + if (ap->a_bnp == NULL) + return (0); + + return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL, + ap->a_runp)); +} + +/* + * Indirect blocks are now on the vnode for the file. They are given negative + * logical block numbers. Indirect blocks are addressed by the negative + * address of the first data block to which they point. Double indirect blocks + * are addressed by one less than the address of the first indirect block to + * which they point. Triple indirect blocks are addressed by one less than + * the address of the first double indirect block to which they point. + * + * ufs_bmaparray does the bmap conversion, and if requested returns the + * array of logical blocks which must be traversed to get to a block. + * Each entry contains the offset into that block that gets you to the + * next block and the disk address of the block (if it is assigned). + */ + +int +ufs_bmaparray(vp, bn, bnp, ap, nump, runp) + struct vnode *vp; + register daddr_t bn; + daddr_t *bnp; + struct indir *ap; + int *nump; + int *runp; +{ + register struct inode *ip; + struct buf *bp; + struct ufsmount *ump; + struct mount *mp; + struct vnode *devvp; + struct indir a[NIADDR], *xap; + daddr_t daddr; + long metalbn; + int error, maxrun, num; + + ip = VTOI(vp); + mp = vp->v_mount; + ump = VFSTOUFS(mp); +#ifdef DIAGNOSTIC + if (ap != NULL && nump == NULL || ap == NULL && nump != NULL) + panic("ufs_bmaparray: invalid arguments"); +#endif + + if (runp) { + /* + * XXX + * If MAXBSIZE is the largest transfer the disks can handle, + * we probably want maxrun to be 1 block less so that we + * don't create a block larger than the device can handle. + */ + *runp = 0; + maxrun = MAXBSIZE / mp->mnt_stat.f_iosize - 1; + } + + xap = ap == NULL ? a : ap; + if (!nump) + nump = # + if (error = ufs_getlbns(vp, bn, xap, nump)) + return (error); + + num = *nump; + if (num == 0) { + *bnp = blkptrtodb(ump, ip->i_db[bn]); + if (*bnp == 0) + *bnp = -1; + else if (runp) + for (++bn; bn < NDADDR && *runp < maxrun && + is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]); + ++bn, ++*runp); + return (0); + } + + + /* Get disk address out of indirect block array */ + daddr = ip->i_ib[xap->in_off]; + + devvp = VFSTOUFS(vp->v_mount)->um_devvp; + for (bp = NULL, ++xap; --num; ++xap) { + /* + * Exit the loop if there is no disk address assigned yet and + * the indirect block isn't in the cache, or if we were + * looking for an indirect block and we've found it. + */ + + metalbn = xap->in_lbn; + if (daddr == 0 && !incore(vp, metalbn) || metalbn == bn) + break; + /* + * If we get here, we've either got the block in the cache + * or we have a disk address for it, go fetch it. + */ + if (bp) + brelse(bp); + + xap->in_exists = 1; + bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0); + if (bp->b_flags & (B_DONE | B_DELWRI)) { + trace(TR_BREADHIT, pack(vp, size), metalbn); + } +#ifdef DIAGNOSTIC + else if (!daddr) + panic("ufs_bmaparry: indirect block not in cache"); +#endif + else { + trace(TR_BREADMISS, pack(vp, size), metalbn); + bp->b_blkno = blkptrtodb(ump, daddr); + bp->b_flags |= B_READ; + VOP_STRATEGY(bp); + curproc->p_stats->p_ru.ru_inblock++; /* XXX */ + if (error = biowait(bp)) { + brelse(bp); + return (error); + } + } + + daddr = ((daddr_t *)bp->b_data)[xap->in_off]; + if (num == 1 && daddr && runp) + for (bn = xap->in_off + 1; + bn < MNINDIR(ump) && *runp < maxrun && + is_sequential(ump, ((daddr_t *)bp->b_data)[bn - 1], + ((daddr_t *)bp->b_data)[bn]); + ++bn, ++*runp); + } + if (bp) + brelse(bp); + + daddr = blkptrtodb(ump, daddr); + *bnp = daddr == 0 ? -1 : daddr; + return (0); +} + +/* + * Create an array of logical block number/offset pairs which represent the + * path of indirect blocks required to access a data block. The first "pair" + * contains the logical block number of the appropriate single, double or + * triple indirect block and the offset into the inode indirect block array. + * Note, the logical block number of the inode single/double/triple indirect + * block appears twice in the array, once with the offset into the i_ib and + * once with the offset into the page itself. + */ +int +ufs_getlbns(vp, bn, ap, nump) + struct vnode *vp; + register daddr_t bn; + struct indir *ap; + int *nump; +{ + long metalbn, realbn; + struct ufsmount *ump; + int blockcnt, i, numlevels, off; + + ump = VFSTOUFS(vp->v_mount); + if (nump) + *nump = 0; + numlevels = 0; + realbn = bn; + if ((long)bn < 0) + bn = -(long)bn; + + /* The first NDADDR blocks are direct blocks. */ + if (bn < NDADDR) + return (0); + + /* + * Determine the number of levels of indirection. After this loop + * is done, blockcnt indicates the number of data blocks possible + * at the given level of indirection, and NIADDR - i is the number + * of levels of indirection needed to locate the requested block. + */ + for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) { + if (i == 0) + return (EFBIG); + blockcnt *= MNINDIR(ump); + if (bn < blockcnt) + break; + } + + /* Calculate the address of the first meta-block. */ + if (realbn >= 0) + metalbn = -(realbn - bn + NIADDR - i); + else + metalbn = -(-realbn - bn + NIADDR - i); + + /* + * At each iteration, off is the offset into the bap array which is + * an array of disk addresses at the current level of indirection. + * The logical block number and the offset in that block are stored + * into the argument array. + */ + ap->in_lbn = metalbn; + ap->in_off = off = NIADDR - i; + ap->in_exists = 0; + ap++; + for (++numlevels; i <= NIADDR; i++) { + /* If searching for a meta-data block, quit when found. */ + if (metalbn == realbn) + break; + + blockcnt /= MNINDIR(ump); + off = (bn / blockcnt) % MNINDIR(ump); + + ++numlevels; + ap->in_lbn = metalbn; + ap->in_off = off; + ap->in_exists = 0; + ++ap; + + metalbn -= -1 + off * blockcnt; + } + if (nump) + *nump = numlevels; + return (0); +} |