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NetBSD/sys/ufs/lfs/ulfs_bmap.c

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/* $NetBSD: ulfs_bmap.c,v 1.5 2013/07/28 01:10:49 dholland Exp $ */
/* from NetBSD: ufs_bmap.c,v 1.50 2013/01/22 09:39:18 dholland Exp */
/*
* 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. 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 8.8 (Berkeley) 8/11/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ulfs_bmap.c,v 1.5 2013/07/28 01:10:49 dholland Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/stat.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 <sys/fstrans.h>
#include <miscfs/specfs/specdev.h>
#include <ufs/lfs/ulfs_inode.h>
#include <ufs/lfs/ulfsmount.h>
#include <ufs/lfs/ulfs_extern.h>
#include <ufs/lfs/ulfs_bswap.h>
static bool
ulfs_issequential(const struct lfs *fs, daddr_t daddr0, daddr_t daddr1)
{
/* for ulfs, blocks in a hole is not 'contiguous'. */
if (daddr0 == 0)
return false;
return (daddr0 + fs->um_seqinc == daddr1);
}
/*
* 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
ulfs_bmap(void *v)
{
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
} */ *ap = v;
int error;
/*
* 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);
fstrans_start(ap->a_vp->v_mount, FSTRANS_SHARED);
error = ulfs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
ap->a_runp, ulfs_issequential);
fstrans_done(ap->a_vp->v_mount);
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.
*
* ulfs_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
ulfs_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, struct indir *ap,
int *nump, int *runp, ulfs_issequential_callback_t is_sequential)
{
struct inode *ip;
struct buf *bp, *cbp;
struct ulfsmount *ump;
struct lfs *fs;
struct mount *mp;
struct indir a[ULFS_NIADDR + 1], *xap;
daddr_t daddr;
daddr_t metalbn;
int error, maxrun = 0, num;
ip = VTOI(vp);
mp = vp->v_mount;
ump = ip->i_ump;
fs = ip->i_lfs;
#ifdef DIAGNOSTIC
if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL))
panic("ulfs_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 = MAXPHYS / mp->mnt_stat.f_iosize - 1;
}
if (bn >= 0 && bn < ULFS_NDADDR) {
if (nump != NULL)
*nump = 0;
if (ump->um_fstype == ULFS1)
daddr = ulfs_rw32(ip->i_ffs1_db[bn],
ULFS_MPNEEDSWAP(fs));
else
daddr = ulfs_rw64(ip->i_ffs2_db[bn],
ULFS_MPNEEDSWAP(fs));
*bnp = blkptrtodb(fs, daddr);
/*
* 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 | SF_SNAPINVAL)) == SF_SNAPSHOT
&& daddr > 0 &&
daddr < fs->um_seqinc) {
*bnp = -1;
} else if (*bnp == 0) {
if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
== SF_SNAPSHOT) {
*bnp = blkptrtodb(fs, bn * fs->um_seqinc);
} else {
*bnp = -1;
}
} else if (runp) {
if (ump->um_fstype == ULFS1) {
for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
is_sequential(fs,
ulfs_rw32(ip->i_ffs1_db[bn - 1],
ULFS_MPNEEDSWAP(fs)),
ulfs_rw32(ip->i_ffs1_db[bn],
ULFS_MPNEEDSWAP(fs)));
++bn, ++*runp);
} else {
for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
is_sequential(fs,
ulfs_rw64(ip->i_ffs2_db[bn - 1],
ULFS_MPNEEDSWAP(fs)),
ulfs_rw64(ip->i_ffs2_db[bn],
ULFS_MPNEEDSWAP(fs)));
++bn, ++*runp);
}
}
return (0);
}
xap = ap == NULL ? a : ap;
if (!nump)
nump = &num;
if ((error = ulfs_getlbns(vp, bn, xap, nump)) != 0)
return (error);
num = *nump;
/* Get disk address out of indirect block array */
if (ump->um_fstype == ULFS1)
daddr = ulfs_rw32(ip->i_ffs1_ib[xap->in_off],
ULFS_MPNEEDSWAP(fs));
else
daddr = ulfs_rw64(ip->i_ffs2_ib[xap->in_off],
ULFS_MPNEEDSWAP(fs));
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 (metalbn == bn)
break;
if (daddr == 0) {
mutex_enter(&bufcache_lock);
cbp = incore(vp, metalbn);
mutex_exit(&bufcache_lock);
if (cbp == NULL)
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, 0);
xap->in_exists = 1;
bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
if (bp == NULL) {
/*
* getblk() above returns NULL only iff we are
* pagedaemon. See the implementation of getblk
* for detail.
*/
return (ENOMEM);
}
if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
trace(TR_BREADHIT, pack(vp, size), metalbn);
}
#ifdef DIAGNOSTIC
else if (!daddr)
panic("ulfs_bmaparray: indirect block not in cache");
#endif
else {
trace(TR_BREADMISS, pack(vp, size), metalbn);
bp->b_blkno = blkptrtodb(fs, daddr);
bp->b_flags |= B_READ;
BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
VOP_STRATEGY(vp, bp);
curlwp->l_ru.ru_inblock++; /* XXX */
if ((error = biowait(bp)) != 0) {
brelse(bp, 0);
return (error);
}
}
if (ump->um_fstype == ULFS1) {
daddr = ulfs_rw32(((u_int32_t *)bp->b_data)[xap->in_off],
ULFS_MPNEEDSWAP(fs));
if (num == 1 && daddr && runp) {
for (bn = xap->in_off + 1;
bn < MNINDIR(fs) && *runp < maxrun &&
is_sequential(fs,
ulfs_rw32(((int32_t *)bp->b_data)[bn-1],
ULFS_MPNEEDSWAP(fs)),
ulfs_rw32(((int32_t *)bp->b_data)[bn],
ULFS_MPNEEDSWAP(fs)));
++bn, ++*runp);
}
} else {
daddr = ulfs_rw64(((u_int64_t *)bp->b_data)[xap->in_off],
ULFS_MPNEEDSWAP(fs));
if (num == 1 && daddr && runp) {
for (bn = xap->in_off + 1;
bn < MNINDIR(fs) && *runp < maxrun &&
is_sequential(fs,
ulfs_rw64(((int64_t *)bp->b_data)[bn-1],
ULFS_MPNEEDSWAP(fs)),
ulfs_rw64(((int64_t *)bp->b_data)[bn],
ULFS_MPNEEDSWAP(fs)));
++bn, ++*runp);
}
}
}
if (bp)
brelse(bp, 0);
/*
* 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 | SF_SNAPINVAL)) == SF_SNAPSHOT
&& daddr > 0 && daddr < fs->um_seqinc) {
*bnp = -1;
return (0);
}
*bnp = blkptrtodb(fs, daddr);
if (*bnp == 0) {
if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
== SF_SNAPSHOT) {
*bnp = blkptrtodb(fs, bn * fs->um_seqinc);
} else {
*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_ffs1_ib and
* once with the offset into the page itself.
*/
int
ulfs_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
{
daddr_t metalbn, realbn;
struct ulfsmount *ump;
struct lfs *fs;
int64_t blockcnt;
int lbc;
int i, numlevels, off;
ump = VFSTOULFS(vp->v_mount);
fs = ump->um_lfs;
if (nump)
*nump = 0;
numlevels = 0;
realbn = bn;
if (bn < 0)
bn = -bn;
KASSERT(bn >= ULFS_NDADDR);
/*
* 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 ULFS_NIADDR - i is the number
* of levels of indirection needed to locate the requested block.
*/
bn -= ULFS_NDADDR;
for (lbc = 0, i = ULFS_NIADDR;; i--, bn -= blockcnt) {
if (i == 0)
return (EFBIG);
lbc += fs->um_lognindir;
blockcnt = (int64_t)1 << lbc;
if (bn < blockcnt)
break;
}
/* Calculate the address of the first meta-block. */
metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + ULFS_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 = ULFS_NIADDR - i;
ap->in_exists = 0;
ap++;
for (++numlevels; i <= ULFS_NIADDR; i++) {
/* If searching for a meta-data block, quit when found. */
if (metalbn == realbn)
break;
lbc -= fs->um_lognindir;
off = (bn >> lbc) & (MNINDIR(fs) - 1);
++numlevels;
ap->in_lbn = metalbn;
ap->in_off = off;
ap->in_exists = 0;
++ap;
metalbn -= -1 + ((int64_t)off << lbc);
}
if (nump)
*nump = numlevels;
return (0);
}
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