truncate.c

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/*
 *  linux/fs/ufs/truncate.c
 *
 * Copyright (C) 1998
 * Daniel Pirkl <[email protected]>
 * Charles University, Faculty of Mathematics and Physics
 *
 *  from
 *
 *  linux/fs/ext2/truncate.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/truncate.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller ([email protected]), 1995
 */

/*
 * Real random numbers for secure rm added 94/02/18
 * Idea from Pierre del Perugia <[email protected]>
 */

/*
 * Adoptation to use page cache and UFS2 write support by
 * Evgeniy Dushistov <[email protected]>, 2006-2007
 */

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/sched.h>

#include "ufs_fs.h"
#include "ufs.h"
#include "swab.h"
#include "util.h"

/*
 * Secure deletion currently doesn't work. It interacts very badly
 * with buffers shared with memory mappings, and for that reason
 * can't be done in the truncate() routines. It should instead be
 * done separately in "release()" before calling the truncate routines
 * that will release the actual file blocks.
 *
 *      Linus
 */

#define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
#define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)


static int ufs_trunc_direct(struct inode *inode)
{
    struct ufs_inode_info *ufsi = UFS_I(inode);
    struct super_block * sb;
    struct ufs_sb_private_info * uspi;
    void *p;
    u64 frag1, frag2, frag3, frag4, block1, block2;
    unsigned frag_to_free, free_count;
    unsigned i, tmp;
    int retry;
    
    UFSD("ENTER: ino %lu\n", inode->i_ino);

    sb = inode->i_sb;
    uspi = UFS_SB(sb)->s_uspi;
    
    frag_to_free = 0;
    free_count = 0;
    retry = 0;
    
    frag1 = DIRECT_FRAGMENT;
    frag4 = min_t(u64, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
    frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
    frag3 = frag4 & ~uspi->s_fpbmask;
    block1 = block2 = 0;
    if (frag2 > frag3) {
        frag2 = frag4;
        frag3 = frag4 = 0;
    } else if (frag2 < frag3) {
        block1 = ufs_fragstoblks (frag2);
        block2 = ufs_fragstoblks (frag3);
    }

    UFSD("ino %lu, frag1 %llu, frag2 %llu, block1 %llu, block2 %llu,"
         " frag3 %llu, frag4 %llu\n", inode->i_ino,
         (unsigned long long)frag1, (unsigned long long)frag2,
         (unsigned long long)block1, (unsigned long long)block2,
         (unsigned long long)frag3, (unsigned long long)frag4);

    if (frag1 >= frag2)
        goto next1;     

    /*
     * Free first free fragments
     */
    p = ufs_get_direct_data_ptr(uspi, ufsi, ufs_fragstoblks(frag1));
    tmp = ufs_data_ptr_to_cpu(sb, p);
    if (!tmp )
        ufs_panic (sb, "ufs_trunc_direct", "internal error");
    frag2 -= frag1;
    frag1 = ufs_fragnum (frag1);

    ufs_free_fragments(inode, tmp + frag1, frag2);
    mark_inode_dirty(inode);
    frag_to_free = tmp + frag1;

next1:
    /*
     * Free whole blocks
     */
    for (i = block1 ; i < block2; i++) {
        p = ufs_get_direct_data_ptr(uspi, ufsi, i);
        tmp = ufs_data_ptr_to_cpu(sb, p);
        if (!tmp)
            continue;
        ufs_data_ptr_clear(uspi, p);

        if (free_count == 0) {
            frag_to_free = tmp;
            free_count = uspi->s_fpb;
        } else if (free_count > 0 && frag_to_free == tmp - free_count)
            free_count += uspi->s_fpb;
        else {
            ufs_free_blocks (inode, frag_to_free, free_count);
            frag_to_free = tmp;
            free_count = uspi->s_fpb;
        }
        mark_inode_dirty(inode);
    }
    
    if (free_count > 0)
        ufs_free_blocks (inode, frag_to_free, free_count);

    if (frag3 >= frag4)
        goto next3;

    /*
     * Free last free fragments
     */
    p = ufs_get_direct_data_ptr(uspi, ufsi, ufs_fragstoblks(frag3));
    tmp = ufs_data_ptr_to_cpu(sb, p);
    if (!tmp )
        ufs_panic(sb, "ufs_truncate_direct", "internal error");
    frag4 = ufs_fragnum (frag4);
    ufs_data_ptr_clear(uspi, p);

    ufs_free_fragments (inode, tmp, frag4);
    mark_inode_dirty(inode);
 next3:

    UFSD("EXIT: ino %lu\n", inode->i_ino);
    return retry;
}


static int ufs_trunc_indirect(struct inode *inode, u64 offset, void *p)
{
    struct super_block * sb;
    struct ufs_sb_private_info * uspi;
    struct ufs_buffer_head * ind_ubh;
    void *ind;
    u64 tmp, indirect_block, i, frag_to_free;
    unsigned free_count;
    int retry;

    UFSD("ENTER: ino %lu, offset %llu, p: %p\n",
         inode->i_ino, (unsigned long long)offset, p);

    BUG_ON(!p);
        
    sb = inode->i_sb;
    uspi = UFS_SB(sb)->s_uspi;

    frag_to_free = 0;
    free_count = 0;
    retry = 0;
    
    tmp = ufs_data_ptr_to_cpu(sb, p);
    if (!tmp)
        return 0;
    ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
    if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
        ubh_brelse (ind_ubh);
        return 1;
    }
    if (!ind_ubh) {
        ufs_data_ptr_clear(uspi, p);
        return 0;
    }

    indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
    for (i = indirect_block; i < uspi->s_apb; i++) {
        ind = ubh_get_data_ptr(uspi, ind_ubh, i);
        tmp = ufs_data_ptr_to_cpu(sb, ind);
        if (!tmp)
            continue;

        ufs_data_ptr_clear(uspi, ind);
        ubh_mark_buffer_dirty(ind_ubh);
        if (free_count == 0) {
            frag_to_free = tmp;
            free_count = uspi->s_fpb;
        } else if (free_count > 0 && frag_to_free == tmp - free_count)
            free_count += uspi->s_fpb;
        else {
            ufs_free_blocks (inode, frag_to_free, free_count);
            frag_to_free = tmp;
            free_count = uspi->s_fpb;
        }

        mark_inode_dirty(inode);
    }

    if (free_count > 0) {
        ufs_free_blocks (inode, frag_to_free, free_count);
    }
    for (i = 0; i < uspi->s_apb; i++)
        if (!ufs_is_data_ptr_zero(uspi,
                      ubh_get_data_ptr(uspi, ind_ubh, i)))
            break;
    if (i >= uspi->s_apb) {
        tmp = ufs_data_ptr_to_cpu(sb, p);
        ufs_data_ptr_clear(uspi, p);

        ufs_free_blocks (inode, tmp, uspi->s_fpb);
        mark_inode_dirty(inode);
        ubh_bforget(ind_ubh);
        ind_ubh = NULL;
    }
    if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh))
        ubh_sync_block(ind_ubh);
    ubh_brelse (ind_ubh);
    
    UFSD("EXIT: ino %lu\n", inode->i_ino);
    
    return retry;
}

static int ufs_trunc_dindirect(struct inode *inode, u64 offset, void *p)
{
    struct super_block * sb;
    struct ufs_sb_private_info * uspi;
    struct ufs_buffer_head *dind_bh;
    u64 i, tmp, dindirect_block;
    void *dind;
    int retry = 0;
    
    UFSD("ENTER: ino %lu\n", inode->i_ino);
    
    sb = inode->i_sb;
    uspi = UFS_SB(sb)->s_uspi;

    dindirect_block = (DIRECT_BLOCK > offset) 
        ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
    retry = 0;
    
    tmp = ufs_data_ptr_to_cpu(sb, p);
    if (!tmp)
        return 0;
    dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
    if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
        ubh_brelse (dind_bh);
        return 1;
    }
    if (!dind_bh) {
        ufs_data_ptr_clear(uspi, p);
        return 0;
    }

    for (i = dindirect_block ; i < uspi->s_apb ; i++) {
        dind = ubh_get_data_ptr(uspi, dind_bh, i);
        tmp = ufs_data_ptr_to_cpu(sb, dind);
        if (!tmp)
            continue;
        retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
        ubh_mark_buffer_dirty(dind_bh);
    }

    for (i = 0; i < uspi->s_apb; i++)
        if (!ufs_is_data_ptr_zero(uspi,
                      ubh_get_data_ptr(uspi, dind_bh, i)))
            break;
    if (i >= uspi->s_apb) {
        tmp = ufs_data_ptr_to_cpu(sb, p);
        ufs_data_ptr_clear(uspi, p);

        ufs_free_blocks(inode, tmp, uspi->s_fpb);
        mark_inode_dirty(inode);
        ubh_bforget(dind_bh);
        dind_bh = NULL;
    }
    if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh))
        ubh_sync_block(dind_bh);
    ubh_brelse (dind_bh);
    
    UFSD("EXIT: ino %lu\n", inode->i_ino);
    
    return retry;
}

static int ufs_trunc_tindirect(struct inode *inode)
{
    struct super_block *sb = inode->i_sb;
    struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
    struct ufs_inode_info *ufsi = UFS_I(inode);
    struct ufs_buffer_head * tind_bh;
    u64 tindirect_block, tmp, i;
    void *tind, *p;
    int retry;
    
    UFSD("ENTER: ino %lu\n", inode->i_ino);

    retry = 0;
    
    tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
        ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;

    p = ufs_get_direct_data_ptr(uspi, ufsi, UFS_TIND_BLOCK);
    if (!(tmp = ufs_data_ptr_to_cpu(sb, p)))
        return 0;
    tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
    if (tmp != ufs_data_ptr_to_cpu(sb, p)) {
        ubh_brelse (tind_bh);
        return 1;
    }
    if (!tind_bh) {
        ufs_data_ptr_clear(uspi, p);
        return 0;
    }

    for (i = tindirect_block ; i < uspi->s_apb ; i++) {
        tind = ubh_get_data_ptr(uspi, tind_bh, i);
        retry |= ufs_trunc_dindirect(inode, UFS_NDADDR + 
            uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
        ubh_mark_buffer_dirty(tind_bh);
    }
    for (i = 0; i < uspi->s_apb; i++)
        if (!ufs_is_data_ptr_zero(uspi,
                      ubh_get_data_ptr(uspi, tind_bh, i)))
            break;
    if (i >= uspi->s_apb) {
        tmp = ufs_data_ptr_to_cpu(sb, p);
        ufs_data_ptr_clear(uspi, p);

        ufs_free_blocks(inode, tmp, uspi->s_fpb);
        mark_inode_dirty(inode);
        ubh_bforget(tind_bh);
        tind_bh = NULL;
    }
    if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh))
        ubh_sync_block(tind_bh);
    ubh_brelse (tind_bh);
    
    UFSD("EXIT: ino %lu\n", inode->i_ino);
    return retry;
}

static int ufs_alloc_lastblock(struct inode *inode)
{
    int err = 0;
    struct super_block *sb = inode->i_sb;
    struct address_space *mapping = inode->i_mapping;
    struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
    unsigned i, end;
    sector_t lastfrag;
    struct page *lastpage;
    struct buffer_head *bh;
    u64 phys64;

    lastfrag = (i_size_read(inode) + uspi->s_fsize - 1) >> uspi->s_fshift;

    if (!lastfrag)
        goto out;

    lastfrag--;

    lastpage = ufs_get_locked_page(mapping, lastfrag >>
                       (PAGE_CACHE_SHIFT - inode->i_blkbits));
       if (IS_ERR(lastpage)) {
               err = -EIO;
               goto out;
       }

       end = lastfrag & ((1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)) - 1);
       bh = page_buffers(lastpage);
       for (i = 0; i < end; ++i)
               bh = bh->b_this_page;


       err = ufs_getfrag_block(inode, lastfrag, bh, 1);

       if (unlikely(err))
           goto out_unlock;

       if (buffer_new(bh)) {
           clear_buffer_new(bh);
           unmap_underlying_metadata(bh->b_bdev,
                     bh->b_blocknr);
           /*
        * we do not zeroize fragment, because of
        * if it maped to hole, it already contains zeroes
        */
           set_buffer_uptodate(bh);
           mark_buffer_dirty(bh);
           set_page_dirty(lastpage);
       }

       if (lastfrag >= UFS_IND_FRAGMENT) {
           end = uspi->s_fpb - ufs_fragnum(lastfrag) - 1;
           phys64 = bh->b_blocknr + 1;
           for (i = 0; i < end; ++i) {
               bh = sb_getblk(sb, i + phys64);
               lock_buffer(bh);
               memset(bh->b_data, 0, sb->s_blocksize);
               set_buffer_uptodate(bh);
               mark_buffer_dirty(bh);
               unlock_buffer(bh);
               sync_dirty_buffer(bh);
               brelse(bh);
           }
       }
out_unlock:
       ufs_put_locked_page(lastpage);
out:
       return err;
}

int ufs_truncate(struct inode *inode, loff_t old_i_size)
{
    struct ufs_inode_info *ufsi = UFS_I(inode);
    struct super_block *sb = inode->i_sb;
    struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
    int retry, err = 0;
    
    UFSD("ENTER: ino %lu, i_size: %llu, old_i_size: %llu\n",
         inode->i_ino, (unsigned long long)i_size_read(inode),
         (unsigned long long)old_i_size);

    if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
          S_ISLNK(inode->i_mode)))
        return -EINVAL;
    if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
        return -EPERM;

    err = ufs_alloc_lastblock(inode);

    if (err) {
        i_size_write(inode, old_i_size);
        goto out;
    }

    block_truncate_page(inode->i_mapping, inode->i_size, ufs_getfrag_block);

    while (1) {
        retry = ufs_trunc_direct(inode);
        retry |= ufs_trunc_indirect(inode, UFS_IND_BLOCK,
                        ufs_get_direct_data_ptr(uspi, ufsi,
                                    UFS_IND_BLOCK));
        retry |= ufs_trunc_dindirect(inode, UFS_IND_BLOCK + uspi->s_apb,
                         ufs_get_direct_data_ptr(uspi, ufsi,
                                     UFS_DIND_BLOCK));
        retry |= ufs_trunc_tindirect (inode);
        if (!retry)
            break;
        if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
            ufs_sync_inode (inode);
        yield();
    }

    inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
    ufsi->i_lastfrag = DIRECT_FRAGMENT;
    mark_inode_dirty(inode);
out:
    UFSD("EXIT: err %d\n", err);
    return err;
}

int ufs_setattr(struct dentry *dentry, struct iattr *attr)
{
    struct inode *inode = dentry->d_inode;
    unsigned int ia_valid = attr->ia_valid;
    int error;

    error = inode_change_ok(inode, attr);
    if (error)
        return error;

    if (ia_valid & ATTR_SIZE && attr->ia_size != inode->i_size) {
        loff_t old_i_size = inode->i_size;

        /* XXX(truncate): truncate_setsize should be called last */
        truncate_setsize(inode, attr->ia_size);

        lock_ufs(inode->i_sb);
        error = ufs_truncate(inode, old_i_size);
        unlock_ufs(inode->i_sb);
        if (error)
            return error;
    }

    setattr_copy(inode, attr);
    mark_inode_dirty(inode);
    return 0;
}

const struct inode_operations ufs_file_inode_operations = {
    .setattr = ufs_setattr,
};