vm: fix a null dereference on out-of-memory

[minix.git] / sys / ufs / ext2fs / ext2fs_inode.c

/*      $NetBSD: ext2fs_inode.c,v 1.74 2011/06/16 09:21:03 hannken 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. 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_inode.c 8.8 (Berkeley) 10/19/94
 * Modified for ext2fs by Manuel Bouyer.
 */

/*
 * Copyright (c) 1997 Manuel Bouyer.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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_inode.c 8.8 (Berkeley) 10/19/94
 * Modified for ext2fs by Manuel Bouyer.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ext2fs_inode.c,v 1.74 2011/06/16 09:21:03 hannken Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/trace.h>
#include <sys/resourcevar.h>
#include <sys/kauth.h>

#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

#include <ufs/ext2fs/ext2fs.h>
#include <ufs/ext2fs/ext2fs_extern.h>

extern int prtactive;

static int ext2fs_indirtrunc(struct inode *, daddr_t, daddr_t,
                                  daddr_t, int, long *);

/*
 * Get the size of an inode.
 */
uint64_t
ext2fs_size(struct inode *ip)
{
        uint64_t size = ip->i_e2fs_size;

        if ((ip->i_e2fs_mode & IFMT) == IFREG)
                size |= (uint64_t)ip->i_e2fs_dacl << 32;
        return size;
}

int
ext2fs_setsize(struct inode *ip, uint64_t size)
{
        if ((ip->i_e2fs_mode & IFMT) == IFREG ||
            ip->i_e2fs_mode == 0) {
                ip->i_e2fs_dacl = size >> 32;
                if (size >= 0x80000000U) {
                        struct m_ext2fs *fs = ip->i_e2fs;

                        if (fs->e2fs.e2fs_rev <= E2FS_REV0) {
                                /* Linux automagically upgrades to REV1 here! */
                                return EFBIG;
                        }
                        if (!(fs->e2fs.e2fs_features_rocompat
                            & EXT2F_ROCOMPAT_LARGEFILE)) {
                                fs->e2fs.e2fs_features_rocompat |=
                                    EXT2F_ROCOMPAT_LARGEFILE;
                                fs->e2fs_fmod = 1;
                        }
                }
        } else if (size >= 0x80000000U)
                return EFBIG;

        ip->i_e2fs_size = size;

        return 0;
}

/*
 * Last reference to an inode.  If necessary, write or delete it.
 */
int
ext2fs_inactive(void *v)
{
        struct vop_inactive_args /* {
                struct vnode *a_vp;
                bool *a_recycle;
        } */ *ap = v;
        struct vnode *vp = ap->a_vp;
        struct inode *ip = VTOI(vp);
        int error = 0;

        if (prtactive && vp->v_usecount != 0)
                vprint("ext2fs_inactive: pushing active", vp);
        /* Get rid of inodes related to stale file handles. */
        if (ip->i_e2fs_mode == 0 || ip->i_e2fs_dtime != 0)
                goto out;

        error = 0;
        if (ip->i_e2fs_nlink == 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
                /* Defer final inode free and update to reclaim.*/
                if (ext2fs_size(ip) != 0) {
                        error = ext2fs_truncate(vp, (off_t)0, 0, NOCRED);
                }
                ip->i_e2fs_dtime = time_second;
                ip->i_flag |= IN_CHANGE | IN_UPDATE;
                ip->i_omode = 1;
        }
        if (ip->i_flag & (IN_CHANGE | IN_UPDATE | IN_MODIFIED)) {
                ext2fs_update(vp, NULL, NULL, 0);
        }
out:
        /*
         * If we are done with the inode, reclaim it
         * so that it can be reused immediately.
         */
        *ap->a_recycle = (ip->i_e2fs_dtime != 0);
        VOP_UNLOCK(vp);
        return (error);
}


/*
 * Update the access, modified, and inode change times as specified by the
 * IACCESS, IUPDATE, and ICHANGE flags respectively. The IMODIFIED flag is
 * used to specify that the inode needs to be updated but that the times have
 * already been set. The access and modified times are taken from the second
 * and third parameters; the inode change time is always taken from the current
 * time. If UPDATE_WAIT or UPDATE_DIROP is set, then wait for the disk
 * write of the inode to complete.
 */
int
ext2fs_update(struct vnode *vp, const struct timespec *acc,
    const struct timespec *mod, int updflags)
{
        struct m_ext2fs *fs;
        struct buf *bp;
        struct inode *ip;
        int error;
        void *cp;
        int flags;

        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                return (0);
        ip = VTOI(vp);
        EXT2FS_ITIMES(ip, acc, mod, NULL);
        if (updflags & UPDATE_CLOSE)
                flags = ip->i_flag & (IN_MODIFIED | IN_ACCESSED);
        else
                flags = ip->i_flag & IN_MODIFIED;
        if (flags == 0)
                return (0);
        fs = ip->i_e2fs;

        error = bread(ip->i_devvp,
                          fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
                          (int)fs->e2fs_bsize, NOCRED, B_MODIFY, &bp);
        if (error) {
                brelse(bp, 0);
                return (error);
        }
        ip->i_flag &= ~(IN_MODIFIED | IN_ACCESSED);
        cp = (char *)bp->b_data +
            (ino_to_fsbo(fs, ip->i_number) * EXT2_DINODE_SIZE(fs));
        e2fs_isave(ip->i_din.e2fs_din, (struct ext2fs_dinode *)cp);
        if ((updflags & (UPDATE_WAIT|UPDATE_DIROP)) != 0 &&
            (flags & IN_MODIFIED) != 0 &&
            (vp->v_mount->mnt_flag & MNT_ASYNC) == 0)
                return (bwrite(bp));
        else {
                bdwrite(bp);
                return (0);
        }
}

#define SINGLE  0       /* index of single indirect block */
#define DOUBLE  1       /* index of double indirect block */
#define TRIPLE  2       /* index of triple indirect block */
/*
 * Truncate the inode oip to at most length size, freeing the
 * disk blocks.
 */
int
ext2fs_truncate(struct vnode *ovp, off_t length, int ioflag,
    kauth_cred_t cred)
{
        daddr_t lastblock;
        struct inode *oip = VTOI(ovp);
        daddr_t bn, lastiblock[NIADDR], indir_lbn[NIADDR];
        /* XXX ondisk32 */
        int32_t oldblks[NDADDR + NIADDR], newblks[NDADDR + NIADDR];
        struct m_ext2fs *fs;
        int offset, size, level;
        long count, blocksreleased = 0;
        int i, nblocks;
        int error, allerror = 0;
        off_t osize;
        int sync;
        struct ufsmount *ump = oip->i_ump;

        if (ovp->v_type == VCHR || ovp->v_type == VBLK ||
            ovp->v_type == VFIFO || ovp->v_type == VSOCK) {
                return 0;
        }

        if (length < 0)
                return (EINVAL);

        if (ovp->v_type == VLNK &&
            (ext2fs_size(oip) < ump->um_maxsymlinklen ||
             (ump->um_maxsymlinklen == 0 && oip->i_e2fs_nblock == 0))) {
                KDASSERT(length == 0);
                memset((char *)&oip->i_din.e2fs_din->e2di_shortlink, 0,
                        (u_int)ext2fs_size(oip));
                (void)ext2fs_setsize(oip, 0);
                oip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2fs_update(ovp, NULL, NULL, 0));
        }
        if (ext2fs_size(oip) == length) {
                /* still do a uvm_vnp_setsize() as writesize may be larger */
                uvm_vnp_setsize(ovp, length);
                oip->i_flag |= IN_CHANGE | IN_UPDATE;
                return (ext2fs_update(ovp, NULL, NULL, 0));
        }
        fs = oip->i_e2fs;
        if (length > ump->um_maxfilesize)
                return (EFBIG);

        osize = ext2fs_size(oip);

        /*
         * Lengthen the size of the file. We must ensure that the
         * last byte of the file is allocated. Since the smallest
         * value of osize is 0, length will be at least 1.
         */
        if (osize < length) {
                uvm_vnp_setwritesize(ovp, length);
                error = ufs_balloc_range(ovp, length - 1, 1, cred,
                    ioflag & IO_SYNC ? B_SYNC : 0);
                if (error) {
                        (void) ext2fs_truncate(ovp, osize, ioflag & IO_SYNC,
                            cred);
                        return (error);
                }
                uvm_vnp_setsize(ovp, length);
                oip->i_flag |= IN_CHANGE | IN_UPDATE;
                KASSERT(error  || ovp->v_size == ext2fs_size(oip));
                return (ext2fs_update(ovp, NULL, NULL, 0));
        }
        /*
         * Shorten the size of the file. If the file is not being
         * truncated to a block boundry, the contents of the
         * partial block following the end of the file must be
         * zero'ed in case it ever become accessible again because
         * of subsequent file growth.
         */
        offset = blkoff(fs, length);
        if (offset != 0) {
                size = fs->e2fs_bsize;

                /* XXXUBC we should handle more than just VREG */
                ubc_zerorange(&ovp->v_uobj, length, size - offset,
                    UBC_UNMAP_FLAG(ovp));
        }
        (void)ext2fs_setsize(oip, length);
        uvm_vnp_setsize(ovp, length);
        /*
         * Calculate index into inode's block list of
         * last direct and indirect blocks (if any)
         * which we want to keep.  Lastblock is -1 when
         * the file is truncated to 0.
         */
        lastblock = lblkno(fs, length + fs->e2fs_bsize - 1) - 1;
        lastiblock[SINGLE] = lastblock - NDADDR;
        lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
        lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
        nblocks = btodb(fs->e2fs_bsize);
        /*
         * Update file and block pointers on disk before we start freeing
         * blocks.  If we crash before free'ing blocks below, the blocks
         * will be returned to the free list.  lastiblock values are also
         * normalized to -1 for calls to ext2fs_indirtrunc below.
         */
        memcpy((void *)oldblks, (void *)&oip->i_e2fs_blocks[0], sizeof oldblks);
        sync = 0;
        for (level = TRIPLE; level >= SINGLE; level--) {
                if (lastiblock[level] < 0 && oldblks[NDADDR + level] != 0) {
                        sync = 1;
                        oip->i_e2fs_blocks[NDADDR + level] = 0;
                        lastiblock[level] = -1;
                }
        }
        for (i = 0; i < NDADDR; i++) {
                if (i > lastblock && oldblks[i] != 0) {
                        sync = 1;
                        oip->i_e2fs_blocks[i] = 0;
                }
        }
        oip->i_flag |= IN_CHANGE | IN_UPDATE;
        if (sync) {
                error = ext2fs_update(ovp, NULL, NULL, UPDATE_WAIT);
                if (error && !allerror)
                        allerror = error;
        }

        /*
         * Having written the new inode to disk, save its new configuration
         * and put back the old block pointers long enough to process them.
         * Note that we save the new block configuration so we can check it
         * when we are done.
         */
        memcpy((void *)newblks, (void *)&oip->i_e2fs_blocks[0], sizeof newblks);
        memcpy((void *)&oip->i_e2fs_blocks[0], (void *)oldblks, sizeof oldblks);

        (void)ext2fs_setsize(oip, osize);
        error = vtruncbuf(ovp, lastblock + 1, 0, 0);
        if (error && !allerror)
                allerror = error;

        /*
         * Indirect blocks first.
         */
        indir_lbn[SINGLE] = -NDADDR;
        indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) -1;
        indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
        for (level = TRIPLE; level >= SINGLE; level--) {
                /* XXX ondisk32 */
                bn = fs2h32(oip->i_e2fs_blocks[NDADDR + level]);
                if (bn != 0) {
                        error = ext2fs_indirtrunc(oip, indir_lbn[level],
                            fsbtodb(fs, bn), lastiblock[level], level, &count);
                        if (error)
                                allerror = error;
                        blocksreleased += count;
                        if (lastiblock[level] < 0) {
                                oip->i_e2fs_blocks[NDADDR + level] = 0;
                                ext2fs_blkfree(oip, bn);
                                blocksreleased += nblocks;
                        }
                }
                if (lastiblock[level] >= 0)
                        goto done;
        }

        /*
         * All whole direct blocks or frags.
         */
        for (i = NDADDR - 1; i > lastblock; i--) {
                /* XXX ondisk32 */
                bn = fs2h32(oip->i_e2fs_blocks[i]);
                if (bn == 0)
                        continue;
                oip->i_e2fs_blocks[i] = 0;
                ext2fs_blkfree(oip, bn);
                blocksreleased += btodb(fs->e2fs_bsize);
        }

done:
#ifdef DIAGNOSTIC
        for (level = SINGLE; level <= TRIPLE; level++)
                if (newblks[NDADDR + level] !=
                    oip->i_e2fs_blocks[NDADDR + level])
                        panic("ext2fs_truncate1");
        for (i = 0; i < NDADDR; i++)
                if (newblks[i] != oip->i_e2fs_blocks[i])
                        panic("ext2fs_truncate2");
        if (length == 0 &&
            (!LIST_EMPTY(&ovp->v_cleanblkhd) ||
             !LIST_EMPTY(&ovp->v_dirtyblkhd)))
                panic("ext2fs_truncate3");
#endif /* DIAGNOSTIC */
        /*
         * Put back the real size.
         */
        (void)ext2fs_setsize(oip, length);
        oip->i_e2fs_nblock -= blocksreleased;
        oip->i_flag |= IN_CHANGE;
        KASSERT(ovp->v_type != VREG || ovp->v_size == ext2fs_size(oip));
        return (allerror);
}

/*
 * Release blocks associated with the inode ip and stored in the indirect
 * block bn.  Blocks are free'd in LIFO order up to (but not including)
 * lastbn.  If level is greater than SINGLE, the block is an indirect block
 * and recursive calls to indirtrunc must be used to cleanse other indirect
 * blocks.
 *
 * NB: triple indirect blocks are untested.
 */
static int
ext2fs_indirtrunc(struct inode *ip, daddr_t lbn, daddr_t dbn, daddr_t lastbn,
                int level, long *countp)
{
        int i;
        struct buf *bp;
        struct m_ext2fs *fs = ip->i_e2fs;
        int32_t *bap;   /* XXX ondisk32 */
        struct vnode *vp;
        daddr_t nb, nlbn, last;
        int32_t *copy = NULL;   /* XXX ondisk32 */
        long blkcount, factor;
        int nblocks, blocksreleased = 0;
        int error = 0, allerror = 0;

        /*
         * Calculate index in current block of last
         * block to be kept.  -1 indicates the entire
         * block so we need not calculate the index.
         */
        factor = 1;
        for (i = SINGLE; i < level; i++)
                factor *= NINDIR(fs);
        last = lastbn;
        if (lastbn > 0)
                last /= factor;
        nblocks = btodb(fs->e2fs_bsize);
        /*
         * Get buffer of block pointers, zero those entries corresponding
         * to blocks to be free'd, and update on disk copy first.  Since
         * double(triple) indirect before single(double) indirect, calls
         * to bmap on these blocks will fail.  However, we already have
         * the on disk address, so we have to set the b_blkno field
         * explicitly instead of letting bread do everything for us.
         */
        vp = ITOV(ip);
        bp = getblk(vp, lbn, (int)fs->e2fs_bsize, 0, 0);
        if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
                /* Braces must be here in case trace evaluates to nothing. */
                trace(TR_BREADHIT, pack(vp, fs->e2fs_bsize), lbn);
        } else {
                trace(TR_BREADMISS, pack(vp, fs->e2fs_bsize), lbn);
                curlwp->l_ru.ru_inblock++;      /* pay for read */
                bp->b_flags |= B_READ;
                if (bp->b_bcount > bp->b_bufsize)
                        panic("ext2fs_indirtrunc: bad buffer size");
                bp->b_blkno = dbn;
                VOP_STRATEGY(vp, bp);
                error = biowait(bp);
        }
        if (error) {
                brelse(bp, 0);
                *countp = 0;
                return (error);
        }

        bap = (int32_t *)bp->b_data;    /* XXX ondisk32 */
        if (lastbn >= 0) {
                /* XXX ondisk32 */
                copy = malloc(fs->e2fs_bsize, M_TEMP, M_WAITOK);
                memcpy((void *)copy, (void *)bap, (u_int)fs->e2fs_bsize);
                memset((void *)&bap[last + 1], 0,
                        (u_int)(NINDIR(fs) - (last + 1)) * sizeof (uint32_t));
                error = bwrite(bp);
                if (error)
                        allerror = error;
                bap = copy;
        }

        /*
         * Recursively free totally unused blocks.
         */
        for (i = NINDIR(fs) - 1,
                nlbn = lbn + 1 - i * factor; i > last;
                i--, nlbn += factor) {
                /* XXX ondisk32 */
                nb = fs2h32(bap[i]);
                if (nb == 0)
                        continue;
                if (level > SINGLE) {
                        error = ext2fs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
                                                   (daddr_t)-1, level - 1,
                                                   &blkcount);
                        if (error)
                                allerror = error;
                        blocksreleased += blkcount;
                }
                ext2fs_blkfree(ip, nb);
                blocksreleased += nblocks;
        }

        /*
         * Recursively free last partial block.
         */
        if (level > SINGLE && lastbn >= 0) {
                last = lastbn % factor;
                /* XXX ondisk32 */
                nb = fs2h32(bap[i]);
                if (nb != 0) {
                        error = ext2fs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
                                                   last, level - 1, &blkcount);
                        if (error)
                                allerror = error;
                        blocksreleased += blkcount;
                }
        }

        if (copy != NULL) {
                free(copy, M_TEMP);
        } else {
                brelse(bp, BC_INVAL);
        }

        *countp = blocksreleased;
        return (allerror);
}