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linux-next/fs/freevxfs/vxfs_bmap.c
Dmitriy Monakhov 82f703bb8c freevxfs: possible null pointer dereference fix 
sb_read may return NULL, so let's explicitly check it.

Signed-off-by: Dmitriy Monakhov <dmonakhov@openvz.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:14:59 -07:00

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/*
* Copyright (c) 2000-2001 Christoph Hellwig.
* 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,
* without modification.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL").
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
/*
* Veritas filesystem driver - filesystem to disk block mapping.
*/
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>
#include "vxfs.h"
#include "vxfs_inode.h"
#include "vxfs_extern.h"
#ifdef DIAGNOSTIC
static void
vxfs_typdump(struct vxfs_typed *typ)
{
printk(KERN_DEBUG "type=%Lu ", typ->vt_hdr >> VXFS_TYPED_TYPESHIFT);
printk("offset=%Lx ", typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
printk("block=%x ", typ->vt_block);
printk("size=%x\n", typ->vt_size);
}
#endif
/**
* vxfs_bmap_ext4 - do bmap for ext4 extents
* @ip: pointer to the inode we do bmap for
* @iblock: logical block.
*
* Description:
* vxfs_bmap_ext4 performs the bmap operation for inodes with
* ext4-style extents (which are much like the traditional UNIX
* inode organisation).
*
* Returns:
* The physical block number on success, else Zero.
*/
static daddr_t
vxfs_bmap_ext4(struct inode *ip, long bn)
{
struct super_block *sb = ip->i_sb;
struct vxfs_inode_info *vip = VXFS_INO(ip);
unsigned long bsize = sb->s_blocksize;
u32 indsize = vip->vii_ext4.ve4_indsize;
int i;
if (indsize > sb->s_blocksize)
goto fail_size;
for (i = 0; i < VXFS_NDADDR; i++) {
struct direct *d = vip->vii_ext4.ve4_direct + i;
if (bn >= 0 && bn < d->size)
return (bn + d->extent);
bn -= d->size;
}
if ((bn / (indsize * indsize * bsize / 4)) == 0) {
struct buffer_head *buf;
daddr_t bno;
u32 *indir;
buf = sb_bread(sb, vip->vii_ext4.ve4_indir[0]);
if (!buf || !buffer_mapped(buf))
goto fail_buf;
indir = (u32 *)buf->b_data;
bno = indir[(bn/indsize) % (indsize*bn)] + (bn%indsize);
brelse(buf);
return bno;
} else
printk(KERN_WARNING "no matching indir?");
return 0;
fail_size:
printk("vxfs: indirect extent too big!\n");
fail_buf:
return 0;
}
/**
* vxfs_bmap_indir - recursion for vxfs_bmap_typed
* @ip: pointer to the inode we do bmap for
* @indir: indirect block we start reading at
* @size: size of the typed area to search
* @block: partially result from further searches
*
* Description:
* vxfs_bmap_indir reads a &struct vxfs_typed at @indir
* and performs the type-defined action.
*
* Return Value:
* The physical block number on success, else Zero.
*
* Note:
* Kernelstack is rare. Unrecurse?
*/
static daddr_t
vxfs_bmap_indir(struct inode *ip, long indir, int size, long block)
{
struct buffer_head *bp = NULL;
daddr_t pblock = 0;
int i;
for (i = 0; i < size * VXFS_TYPED_PER_BLOCK(ip->i_sb); i++) {
struct vxfs_typed *typ;
int64_t off;
bp = sb_bread(ip->i_sb,
indir + (i / VXFS_TYPED_PER_BLOCK(ip->i_sb)));
if (!bp || !buffer_mapped(bp))
return 0;
typ = ((struct vxfs_typed *)bp->b_data) +
(i % VXFS_TYPED_PER_BLOCK(ip->i_sb));
off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
if (block < off) {
brelse(bp);
continue;
}
switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
case VXFS_TYPED_INDIRECT:
pblock = vxfs_bmap_indir(ip, typ->vt_block,
typ->vt_size, block - off);
if (pblock == -2)
break;
goto out;
case VXFS_TYPED_DATA:
if ((block - off) >= typ->vt_size)
break;
pblock = (typ->vt_block + block - off);
goto out;
case VXFS_TYPED_INDIRECT_DEV4:
case VXFS_TYPED_DATA_DEV4: {
struct vxfs_typed_dev4 *typ4 =
(struct vxfs_typed_dev4 *)typ;
printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
(unsigned long long) typ4->vd4_block,
(unsigned long long) typ4->vd4_size,
typ4->vd4_dev);
goto fail;
}
default:
BUG();
}
brelse(bp);
}
fail:
pblock = 0;
out:
brelse(bp);
return (pblock);
}
/**
* vxfs_bmap_typed - bmap for typed extents
* @ip: pointer to the inode we do bmap for
* @iblock: logical block
*
* Description:
* Performs the bmap operation for typed extents.
*
* Return Value:
* The physical block number on success, else Zero.
*/
static daddr_t
vxfs_bmap_typed(struct inode *ip, long iblock)
{
struct vxfs_inode_info *vip = VXFS_INO(ip);
daddr_t pblock = 0;
int i;
for (i = 0; i < VXFS_NTYPED; i++) {
struct vxfs_typed *typ = vip->vii_org.typed + i;
int64_t off = (typ->vt_hdr & VXFS_TYPED_OFFSETMASK);
#ifdef DIAGNOSTIC
vxfs_typdump(typ);
#endif
if (iblock < off)
continue;
switch ((u_int32_t)(typ->vt_hdr >> VXFS_TYPED_TYPESHIFT)) {
case VXFS_TYPED_INDIRECT:
pblock = vxfs_bmap_indir(ip, typ->vt_block,
typ->vt_size, iblock - off);
if (pblock == -2)
break;
return (pblock);
case VXFS_TYPED_DATA:
if ((iblock - off) < typ->vt_size)
return (typ->vt_block + iblock - off);
break;
case VXFS_TYPED_INDIRECT_DEV4:
case VXFS_TYPED_DATA_DEV4: {
struct vxfs_typed_dev4 *typ4 =
(struct vxfs_typed_dev4 *)typ;
printk(KERN_INFO "\n\nTYPED_DEV4 detected!\n");
printk(KERN_INFO "block: %Lu\tsize: %Ld\tdev: %d\n",
(unsigned long long) typ4->vd4_block,
(unsigned long long) typ4->vd4_size,
typ4->vd4_dev);
return 0;
}
default:
BUG();
}
}
return 0;
}
/**
* vxfs_bmap1 - vxfs-internal bmap operation
* @ip: pointer to the inode we do bmap for
* @iblock: logical block
*
* Description:
* vxfs_bmap1 perfoms a logical to physical block mapping
* for vxfs-internal purposes.
*
* Return Value:
* The physical block number on success, else Zero.
*/
daddr_t
vxfs_bmap1(struct inode *ip, long iblock)
{
struct vxfs_inode_info *vip = VXFS_INO(ip);
if (VXFS_ISEXT4(vip))
return vxfs_bmap_ext4(ip, iblock);
if (VXFS_ISTYPED(vip))
return vxfs_bmap_typed(ip, iblock);
if (VXFS_ISNONE(vip))
goto unsupp;
if (VXFS_ISIMMED(vip))
goto unsupp;
printk(KERN_WARNING "vxfs: inode %ld has no valid orgtype (%x)\n",
ip->i_ino, vip->vii_orgtype);
BUG();
unsupp:
printk(KERN_WARNING "vxfs: inode %ld has an unsupported orgtype (%x)\n",
ip->i_ino, vip->vii_orgtype);
return 0;
}
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