[funini.com] -> [kei@sodan] -> Kernel Reading

root/fs/ufs/truncate.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. ufs_trunc_direct
  2. ufs_trunc_indirect
  3. ufs_trunc_dindirect
  4. ufs_trunc_tindirect
  5. ufs_alloc_lastblock
  6. ufs_truncate
  7. ufs_setattr

/*
 *  linux/fs/ufs/truncate.c
 *
 * Copyright (C) 1998
 * Daniel Pirkl <daniel.pirkl@email.cz>
 * Charles University, Faculty of Mathematics and Physics
 *
 *  from
 *
 *  linux/fs/ext2/truncate.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * 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 (davem@caip.rutgers.edu), 1995
 */

/*
 * Real random numbers for secure rm added 94/02/18
 * Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
 */

/*
 * Adoptation to use page cache and UFS2 write support by
 * Evgeniy Dushistov <dushistov@mail.ru>, 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/smp_lock.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(u32, 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_ll_rw_block(SWRITE, ind_ubh);
                ubh_wait_on_buffer (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_ll_rw_block(SWRITE, dind_bh);
                ubh_wait_on_buffer (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_ll_rw_block(SWRITE, tind_bh);
                ubh_wait_on_buffer (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);

        lock_kernel();
        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);
                blk_run_address_space(inode->i_mapping);
                yield();
        }

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


/*
 * We don't define our `inode->i_op->truncate', and call it here,
 * because of:
 * - there is no way to know old size
 * - there is no way inform user about error, if it happens in `truncate'
 */
static 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 != i_size_read(inode)) {
                loff_t old_i_size = inode->i_size;
                error = vmtruncate(inode, attr->ia_size);
                if (error)
                        return error;
                error = ufs_truncate(inode, old_i_size);
                if (error)
                        return error;
        }
        return inode_setattr(inode, attr);
}

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

/* [<][>][^][v][top][bottom][index][help] */

[funini.com] -> [kei@sodan] -> Kernel Reading