diff options
Diffstat (limited to 'sys/fs/ext2fs/ext2_bmap.c')
| -rw-r--r-- | sys/fs/ext2fs/ext2_bmap.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/sys/fs/ext2fs/ext2_bmap.c b/sys/fs/ext2fs/ext2_bmap.c new file mode 100644 index 0000000..c742188 --- /dev/null +++ b/sys/fs/ext2fs/ext2_bmap.c @@ -0,0 +1,334 @@ +/*- + * 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. + * 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 8.7 (Berkeley) 3/21/95 + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/bio.h> +#include <sys/buf.h> +#include <sys/proc.h> +#include <sys/vnode.h> +#include <sys/mount.h> +#include <sys/resourcevar.h> +#include <sys/stat.h> + +#include <fs/ext2fs/inode.h> +#include <fs/ext2fs/ext2fs.h> +#include <fs/ext2fs/ext2_mount.h> +#include <fs/ext2fs/ext2_extern.h> + +/* + * Bmap converts 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 +ext2_bmap(ap) + struct vop_bmap_args /* { + struct vnode *a_vp; + daddr_t a_bn; + struct bufobj **a_bop; + daddr_t *a_bnp; + int *a_runp; + int *a_runb; + } */ *ap; +{ + int32_t blkno; + int error; + + /* + * Check for underlying vnode requests and ensure that logical + * to physical mapping is requested. + */ + if (ap->a_bop != NULL) + *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj; + if (ap->a_bnp == NULL) + return (0); + + error = ext2_bmaparray(ap->a_vp, ap->a_bn, &blkno, + ap->a_runp, ap->a_runb); + *ap->a_bnp = blkno; + return (error); +} + +/* + * 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. + * + * ext2_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 +ext2_bmaparray(vp, bn, bnp, runp, runb) + struct vnode *vp; + int32_t bn; + int32_t *bnp; + int *runp; + int *runb; +{ + struct inode *ip; + struct buf *bp; + struct ext2mount *ump; + struct mount *mp; + struct vnode *devvp; + struct indir a[NIADDR+1], *ap; + int32_t daddr; + long metalbn; + int error, num, maxrun = 0, bsize; + int *nump; + + ap = NULL; + ip = VTOI(vp); + mp = vp->v_mount; + ump = VFSTOEXT2(mp); + devvp = ump->um_devvp; + + bsize = EXT2_BLOCK_SIZE(ump->um_e2fs); + + if (runp) { + maxrun = mp->mnt_iosize_max / bsize - 1; + *runp = 0; + } + + if (runb) { + *runb = 0; + } + + + ap = a; + nump = # + error = ext2_getlbns(vp, bn, ap, nump); + if (error) + return (error); + + num = *nump; + if (num == 0) { + *bnp = blkptrtodb(ump, ip->i_db[bn]); + if (*bnp == 0) { + *bnp = -1; + } else if (runp) { + int32_t bnb = bn; + for (++bn; bn < NDADDR && *runp < maxrun && + is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]); + ++bn, ++*runp); + bn = bnb; + if (runb && (bn > 0)) { + for (--bn; (bn >= 0) && (*runb < maxrun) && + is_sequential(ump, ip->i_db[bn], + ip->i_db[bn+1]); + --bn, ++*runb); + } + } + return (0); + } + + + /* Get disk address out of indirect block array */ + daddr = ip->i_ib[ap->in_off]; + + for (bp = NULL, ++ap; --num; ++ap) { + /* + * 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 = ap->in_lbn; + if ((daddr == 0 && !incore(&vp->v_bufobj, 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) + bqrelse(bp); + + ap->in_exists = 1; + bp = getblk(vp, metalbn, bsize, 0, 0, 0); + if ((bp->b_flags & B_CACHE) == 0) { +#ifdef DIAGNOSTIC + if (!daddr) + panic("ufs_bmaparray: indirect block not in cache"); +#endif + bp->b_blkno = blkptrtodb(ump, daddr); + bp->b_iocmd = BIO_READ; + bp->b_flags &= ~B_INVAL; + bp->b_ioflags &= ~BIO_ERROR; + vfs_busy_pages(bp, 0); + bp->b_iooffset = dbtob(bp->b_blkno); + bstrategy(bp); + curthread->td_ru.ru_inblock++; + error = bufwait(bp); + if (error) { + brelse(bp); + return (error); + } + } + + daddr = ((int32_t *)bp->b_data)[ap->in_off]; + if (num == 1 && daddr && runp) { + for (bn = ap->in_off + 1; + bn < MNINDIR(ump) && *runp < maxrun && + is_sequential(ump, + ((int32_t *)bp->b_data)[bn - 1], + ((int32_t *)bp->b_data)[bn]); + ++bn, ++*runp); + bn = ap->in_off; + if (runb && bn) { + for(--bn; bn >= 0 && *runb < maxrun && + is_sequential(ump, ((int32_t *)bp->b_data)[bn], + ((int32_t *)bp->b_data)[bn+1]); + --bn, ++*runb); + } + } + } + if (bp) + bqrelse(bp); + + /* + * Since this is FFS independent code, we are out of scope for the + * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they + * will fall in the range 1..um_seqinc, so we use that test and + * return a request for a zeroed out buffer if attempts are made + * to read a BLK_NOCOPY or BLK_SNAP block. + */ + if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){ + *bnp = -1; + return (0); + } + *bnp = blkptrtodb(ump, daddr); + if (*bnp == 0) { + *bnp = -1; + } + 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 +ext2_getlbns(vp, bn, ap, nump) + struct vnode *vp; + int32_t bn; + struct indir *ap; + int *nump; +{ + long blockcnt, metalbn, realbn; + struct ext2mount *ump; + int i, numlevels, off; + int64_t qblockcnt; + + ump = VFSTOEXT2(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 previous 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); + /* + * Use int64_t's here to avoid overflow for triple indirect + * blocks when longs have 32 bits and the block size is more + * than 4K. + */ + qblockcnt = (int64_t)blockcnt * MNINDIR(ump); + if (bn < qblockcnt) + break; + blockcnt = qblockcnt; + } + + /* 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; + + off = (bn / blockcnt) % MNINDIR(ump); + + ++numlevels; + ap->in_lbn = metalbn; + ap->in_off = off; + ap->in_exists = 0; + ++ap; + + metalbn -= -1 + off * blockcnt; + blockcnt /= MNINDIR(ump); + } + if (nump) + *nump = numlevels; + return (0); +} |
