| 1 |
1628 |
jcastillo |
/*
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| 2 |
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* linux/fs/ext2/truncate.c
|
| 3 |
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*
|
| 4 |
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* Copyright (C) 1992, 1993, 1994, 1995
|
| 5 |
|
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* Remy Card (card@masi.ibp.fr)
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| 6 |
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* Laboratoire MASI - Institut Blaise Pascal
|
| 7 |
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* Universite Pierre et Marie Curie (Paris VI)
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| 8 |
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*
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| 9 |
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* from
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| 10 |
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*
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| 11 |
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* linux/fs/minix/truncate.c
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| 12 |
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*
|
| 13 |
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* Copyright (C) 1991, 1992 Linus Torvalds
|
| 14 |
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*
|
| 15 |
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* Big-endian to little-endian byte-swapping/bitmaps by
|
| 16 |
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* David S. Miller (davem@caip.rutgers.edu), 1995
|
| 17 |
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*/
|
| 18 |
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| 19 |
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/*
|
| 20 |
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* Real random numbers for secure rm added 94/02/18
|
| 21 |
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* Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
|
| 22 |
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*/
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| 23 |
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| 24 |
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#include <linux/errno.h>
|
| 25 |
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#include <linux/fs.h>
|
| 26 |
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#include <linux/ext2_fs.h>
|
| 27 |
|
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#include <linux/fcntl.h>
|
| 28 |
|
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#include <linux/sched.h>
|
| 29 |
|
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#include <linux/stat.h>
|
| 30 |
|
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#include <linux/locks.h>
|
| 31 |
|
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#include <linux/string.h>
|
| 32 |
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|
| 33 |
|
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#if 0
|
| 34 |
|
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|
| 35 |
|
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/*
|
| 36 |
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* Secure deletion currently doesn't work. It interacts very badly
|
| 37 |
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* with buffers shared with memory mappings, and for that reason
|
| 38 |
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* can't be done in the truncate() routines. It should instead be
|
| 39 |
|
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* done separately in "release()" before calling the truncate routines
|
| 40 |
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* that will release the actual file blocks.
|
| 41 |
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*
|
| 42 |
|
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* Linus
|
| 43 |
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*/
|
| 44 |
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static int ext2_secrm_seed = 152; /* Random generator base */
|
| 45 |
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|
|
| 46 |
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#define RANDOM_INT (ext2_secrm_seed = ext2_secrm_seed * 69069l +1)
|
| 47 |
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#endif
|
| 48 |
|
|
|
| 49 |
|
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/*
|
| 50 |
|
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* Truncate has the most races in the whole filesystem: coding it is
|
| 51 |
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* a pain in the a**. Especially as I don't do any locking...
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| 52 |
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*
|
| 53 |
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* The code may look a bit weird, but that's just because I've tried to
|
| 54 |
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* handle things like file-size changes in a somewhat graceful manner.
|
| 55 |
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* Anyway, truncating a file at the same time somebody else writes to it
|
| 56 |
|
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* is likely to result in pretty weird behaviour...
|
| 57 |
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*
|
| 58 |
|
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* The new code handles normal truncates (size = 0) as well as the more
|
| 59 |
|
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* general case (size = XXX). I hope.
|
| 60 |
|
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*/
|
| 61 |
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|
| 62 |
|
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static int trunc_direct (struct inode * inode)
|
| 63 |
|
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{
|
| 64 |
|
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u32 * p;
|
| 65 |
|
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int i, tmp;
|
| 66 |
|
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struct buffer_head * bh;
|
| 67 |
|
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unsigned long block_to_free = 0;
|
| 68 |
|
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unsigned long free_count = 0;
|
| 69 |
|
|
int retry = 0;
|
| 70 |
|
|
int blocks = inode->i_sb->s_blocksize / 512;
|
| 71 |
|
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#define DIRECT_BLOCK ((inode->i_size + inode->i_sb->s_blocksize - 1) / \
|
| 72 |
|
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inode->i_sb->s_blocksize)
|
| 73 |
|
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int direct_block = DIRECT_BLOCK;
|
| 74 |
|
|
|
| 75 |
|
|
repeat:
|
| 76 |
|
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for (i = direct_block ; i < EXT2_NDIR_BLOCKS ; i++) {
|
| 77 |
|
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p = inode->u.ext2_i.i_data + i;
|
| 78 |
|
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tmp = *p;
|
| 79 |
|
|
if (!tmp)
|
| 80 |
|
|
continue;
|
| 81 |
|
|
bh = get_hash_table (inode->i_dev, tmp,
|
| 82 |
|
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inode->i_sb->s_blocksize);
|
| 83 |
|
|
if (i < direct_block) {
|
| 84 |
|
|
brelse (bh);
|
| 85 |
|
|
goto repeat;
|
| 86 |
|
|
}
|
| 87 |
|
|
if ((bh && bh->b_count != 1) || tmp != *p) {
|
| 88 |
|
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retry = 1;
|
| 89 |
|
|
brelse (bh);
|
| 90 |
|
|
continue;
|
| 91 |
|
|
}
|
| 92 |
|
|
*p = 0;
|
| 93 |
|
|
inode->i_blocks -= blocks;
|
| 94 |
|
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inode->i_dirt = 1;
|
| 95 |
|
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bforget(bh);
|
| 96 |
|
|
if (free_count == 0) {
|
| 97 |
|
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block_to_free = tmp;
|
| 98 |
|
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free_count++;
|
| 99 |
|
|
} else if (free_count > 0 && block_to_free == tmp - free_count)
|
| 100 |
|
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free_count++;
|
| 101 |
|
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else {
|
| 102 |
|
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ext2_free_blocks (inode, block_to_free, free_count);
|
| 103 |
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block_to_free = tmp;
|
| 104 |
|
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free_count = 1;
|
| 105 |
|
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}
|
| 106 |
|
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/* ext2_free_blocks (inode, tmp, 1); */
|
| 107 |
|
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}
|
| 108 |
|
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if (free_count > 0)
|
| 109 |
|
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ext2_free_blocks (inode, block_to_free, free_count);
|
| 110 |
|
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return retry;
|
| 111 |
|
|
}
|
| 112 |
|
|
|
| 113 |
|
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static int trunc_indirect (struct inode * inode, int offset, u32 * p)
|
| 114 |
|
|
{
|
| 115 |
|
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int i, tmp;
|
| 116 |
|
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struct buffer_head * bh;
|
| 117 |
|
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struct buffer_head * ind_bh;
|
| 118 |
|
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u32 * ind;
|
| 119 |
|
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unsigned long block_to_free = 0;
|
| 120 |
|
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unsigned long free_count = 0;
|
| 121 |
|
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int retry = 0;
|
| 122 |
|
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int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
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| 123 |
|
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int blocks = inode->i_sb->s_blocksize / 512;
|
| 124 |
|
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#define INDIRECT_BLOCK ((int)DIRECT_BLOCK - offset)
|
| 125 |
|
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int indirect_block = INDIRECT_BLOCK;
|
| 126 |
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|
|
| 127 |
|
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tmp = *p;
|
| 128 |
|
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if (!tmp)
|
| 129 |
|
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return 0;
|
| 130 |
|
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ind_bh = bread (inode->i_dev, tmp, inode->i_sb->s_blocksize);
|
| 131 |
|
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if (tmp != *p) {
|
| 132 |
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brelse (ind_bh);
|
| 133 |
|
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return 1;
|
| 134 |
|
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}
|
| 135 |
|
|
if (!ind_bh) {
|
| 136 |
|
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*p = 0;
|
| 137 |
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return 0;
|
| 138 |
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}
|
| 139 |
|
|
repeat:
|
| 140 |
|
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for (i = indirect_block ; i < addr_per_block ; i++) {
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| 141 |
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if (i < 0)
|
| 142 |
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i = 0;
|
| 143 |
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if (i < indirect_block)
|
| 144 |
|
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goto repeat;
|
| 145 |
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ind = i + (u32 *) ind_bh->b_data;
|
| 146 |
|
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tmp = swab32(*ind);
|
| 147 |
|
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if (!tmp)
|
| 148 |
|
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continue;
|
| 149 |
|
|
bh = get_hash_table (inode->i_dev, tmp,
|
| 150 |
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inode->i_sb->s_blocksize);
|
| 151 |
|
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if (i < indirect_block) {
|
| 152 |
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brelse (bh);
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| 153 |
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goto repeat;
|
| 154 |
|
|
}
|
| 155 |
|
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if ((bh && bh->b_count != 1) || tmp != swab32(*ind)) {
|
| 156 |
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retry = 1;
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| 157 |
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brelse (bh);
|
| 158 |
|
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continue;
|
| 159 |
|
|
}
|
| 160 |
|
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*ind = swab32(0);
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| 161 |
|
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mark_buffer_dirty(ind_bh, 1);
|
| 162 |
|
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bforget(bh);
|
| 163 |
|
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if (free_count == 0) {
|
| 164 |
|
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block_to_free = tmp;
|
| 165 |
|
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free_count++;
|
| 166 |
|
|
} else if (free_count > 0 && block_to_free == tmp - free_count)
|
| 167 |
|
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free_count++;
|
| 168 |
|
|
else {
|
| 169 |
|
|
ext2_free_blocks (inode, block_to_free, free_count);
|
| 170 |
|
|
block_to_free = tmp;
|
| 171 |
|
|
free_count = 1;
|
| 172 |
|
|
}
|
| 173 |
|
|
/* ext2_free_blocks (inode, tmp, 1); */
|
| 174 |
|
|
inode->i_blocks -= blocks;
|
| 175 |
|
|
inode->i_dirt = 1;
|
| 176 |
|
|
}
|
| 177 |
|
|
if (free_count > 0)
|
| 178 |
|
|
ext2_free_blocks (inode, block_to_free, free_count);
|
| 179 |
|
|
ind = (u32 *) ind_bh->b_data;
|
| 180 |
|
|
for (i = 0; i < addr_per_block; i++)
|
| 181 |
|
|
if (swab32(*(ind++)))
|
| 182 |
|
|
break;
|
| 183 |
|
|
if (i >= addr_per_block)
|
| 184 |
|
|
if (ind_bh->b_count != 1)
|
| 185 |
|
|
retry = 1;
|
| 186 |
|
|
else {
|
| 187 |
|
|
tmp = *p;
|
| 188 |
|
|
*p = 0;
|
| 189 |
|
|
inode->i_blocks -= blocks;
|
| 190 |
|
|
inode->i_dirt = 1;
|
| 191 |
|
|
ext2_free_blocks (inode, tmp, 1);
|
| 192 |
|
|
}
|
| 193 |
|
|
if (IS_SYNC(inode) && buffer_dirty(ind_bh)) {
|
| 194 |
|
|
ll_rw_block (WRITE, 1, &ind_bh);
|
| 195 |
|
|
wait_on_buffer (ind_bh);
|
| 196 |
|
|
}
|
| 197 |
|
|
brelse (ind_bh);
|
| 198 |
|
|
return retry;
|
| 199 |
|
|
}
|
| 200 |
|
|
|
| 201 |
|
|
static int trunc_indirect_swab32 (struct inode * inode, int offset, u32 * p)
|
| 202 |
|
|
{
|
| 203 |
|
|
int i, tmp;
|
| 204 |
|
|
struct buffer_head * bh;
|
| 205 |
|
|
struct buffer_head * ind_bh;
|
| 206 |
|
|
u32 * ind;
|
| 207 |
|
|
unsigned long block_to_free = 0;
|
| 208 |
|
|
unsigned long free_count = 0;
|
| 209 |
|
|
int retry = 0;
|
| 210 |
|
|
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
|
| 211 |
|
|
int blocks = inode->i_sb->s_blocksize / 512;
|
| 212 |
|
|
int indirect_block = INDIRECT_BLOCK;
|
| 213 |
|
|
|
| 214 |
|
|
tmp = swab32(*p);
|
| 215 |
|
|
if (!tmp)
|
| 216 |
|
|
return 0;
|
| 217 |
|
|
ind_bh = bread (inode->i_dev, tmp, inode->i_sb->s_blocksize);
|
| 218 |
|
|
if (tmp != swab32(*p)) {
|
| 219 |
|
|
brelse (ind_bh);
|
| 220 |
|
|
return 1;
|
| 221 |
|
|
}
|
| 222 |
|
|
if (!ind_bh) {
|
| 223 |
|
|
*p = swab32(0);
|
| 224 |
|
|
return 0;
|
| 225 |
|
|
}
|
| 226 |
|
|
repeat:
|
| 227 |
|
|
for (i = indirect_block ; i < addr_per_block ; i++) {
|
| 228 |
|
|
if (i < 0)
|
| 229 |
|
|
i = 0;
|
| 230 |
|
|
if (i < indirect_block)
|
| 231 |
|
|
goto repeat;
|
| 232 |
|
|
ind = i + (u32 *) ind_bh->b_data;
|
| 233 |
|
|
tmp = swab32(*ind);
|
| 234 |
|
|
if (!tmp)
|
| 235 |
|
|
continue;
|
| 236 |
|
|
bh = get_hash_table (inode->i_dev, tmp,
|
| 237 |
|
|
inode->i_sb->s_blocksize);
|
| 238 |
|
|
if (i < indirect_block) {
|
| 239 |
|
|
brelse (bh);
|
| 240 |
|
|
goto repeat;
|
| 241 |
|
|
}
|
| 242 |
|
|
if ((bh && bh->b_count != 1) || tmp != swab32(*ind)) {
|
| 243 |
|
|
retry = 1;
|
| 244 |
|
|
brelse (bh);
|
| 245 |
|
|
continue;
|
| 246 |
|
|
}
|
| 247 |
|
|
*ind = swab32(0);
|
| 248 |
|
|
mark_buffer_dirty(ind_bh, 1);
|
| 249 |
|
|
bforget(bh);
|
| 250 |
|
|
if (free_count == 0) {
|
| 251 |
|
|
block_to_free = tmp;
|
| 252 |
|
|
free_count++;
|
| 253 |
|
|
} else if (free_count > 0 && block_to_free == tmp - free_count)
|
| 254 |
|
|
free_count++;
|
| 255 |
|
|
else {
|
| 256 |
|
|
ext2_free_blocks (inode, block_to_free, free_count);
|
| 257 |
|
|
block_to_free = tmp;
|
| 258 |
|
|
free_count = 1;
|
| 259 |
|
|
}
|
| 260 |
|
|
/* ext2_free_blocks (inode, tmp, 1); */
|
| 261 |
|
|
inode->i_blocks -= blocks;
|
| 262 |
|
|
inode->i_dirt = 1;
|
| 263 |
|
|
}
|
| 264 |
|
|
if (free_count > 0)
|
| 265 |
|
|
ext2_free_blocks (inode, block_to_free, free_count);
|
| 266 |
|
|
ind = (u32 *) ind_bh->b_data;
|
| 267 |
|
|
for (i = 0; i < addr_per_block; i++)
|
| 268 |
|
|
if (swab32(*(ind++)))
|
| 269 |
|
|
break;
|
| 270 |
|
|
if (i >= addr_per_block)
|
| 271 |
|
|
if (ind_bh->b_count != 1)
|
| 272 |
|
|
retry = 1;
|
| 273 |
|
|
else {
|
| 274 |
|
|
tmp = swab32(*p);
|
| 275 |
|
|
*p = swab32(0);
|
| 276 |
|
|
inode->i_blocks -= blocks;
|
| 277 |
|
|
inode->i_dirt = 1;
|
| 278 |
|
|
ext2_free_blocks (inode, tmp, 1);
|
| 279 |
|
|
}
|
| 280 |
|
|
if (IS_SYNC(inode) && buffer_dirty(ind_bh)) {
|
| 281 |
|
|
ll_rw_block (WRITE, 1, &ind_bh);
|
| 282 |
|
|
wait_on_buffer (ind_bh);
|
| 283 |
|
|
}
|
| 284 |
|
|
brelse (ind_bh);
|
| 285 |
|
|
return retry;
|
| 286 |
|
|
}
|
| 287 |
|
|
|
| 288 |
|
|
static int trunc_dindirect (struct inode * inode, int offset,
|
| 289 |
|
|
u32 * p)
|
| 290 |
|
|
{
|
| 291 |
|
|
int i, tmp;
|
| 292 |
|
|
struct buffer_head * dind_bh;
|
| 293 |
|
|
u32 * dind;
|
| 294 |
|
|
int retry = 0;
|
| 295 |
|
|
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
|
| 296 |
|
|
int blocks = inode->i_sb->s_blocksize / 512;
|
| 297 |
|
|
#define DINDIRECT_BLOCK (((int)DIRECT_BLOCK - offset) / addr_per_block)
|
| 298 |
|
|
int dindirect_block = DINDIRECT_BLOCK;
|
| 299 |
|
|
|
| 300 |
|
|
tmp = *p;
|
| 301 |
|
|
if (!tmp)
|
| 302 |
|
|
return 0;
|
| 303 |
|
|
dind_bh = bread (inode->i_dev, tmp, inode->i_sb->s_blocksize);
|
| 304 |
|
|
if (tmp != *p) {
|
| 305 |
|
|
brelse (dind_bh);
|
| 306 |
|
|
return 1;
|
| 307 |
|
|
}
|
| 308 |
|
|
if (!dind_bh) {
|
| 309 |
|
|
*p = 0;
|
| 310 |
|
|
return 0;
|
| 311 |
|
|
}
|
| 312 |
|
|
repeat:
|
| 313 |
|
|
for (i = dindirect_block ; i < addr_per_block ; i++) {
|
| 314 |
|
|
if (i < 0)
|
| 315 |
|
|
i = 0;
|
| 316 |
|
|
if (i < dindirect_block)
|
| 317 |
|
|
goto repeat;
|
| 318 |
|
|
dind = i + (u32 *) dind_bh->b_data;
|
| 319 |
|
|
tmp = swab32(*dind);
|
| 320 |
|
|
if (!tmp)
|
| 321 |
|
|
continue;
|
| 322 |
|
|
retry |= trunc_indirect_swab32 (inode, offset + (i * addr_per_block),
|
| 323 |
|
|
dind);
|
| 324 |
|
|
mark_buffer_dirty(dind_bh, 1);
|
| 325 |
|
|
}
|
| 326 |
|
|
dind = (u32 *) dind_bh->b_data;
|
| 327 |
|
|
for (i = 0; i < addr_per_block; i++)
|
| 328 |
|
|
if (swab32(*(dind++)))
|
| 329 |
|
|
break;
|
| 330 |
|
|
if (i >= addr_per_block)
|
| 331 |
|
|
if (dind_bh->b_count != 1)
|
| 332 |
|
|
retry = 1;
|
| 333 |
|
|
else {
|
| 334 |
|
|
tmp = *p;
|
| 335 |
|
|
*p = 0;
|
| 336 |
|
|
inode->i_blocks -= blocks;
|
| 337 |
|
|
inode->i_dirt = 1;
|
| 338 |
|
|
ext2_free_blocks (inode, tmp, 1);
|
| 339 |
|
|
}
|
| 340 |
|
|
if (IS_SYNC(inode) && buffer_dirty(dind_bh)) {
|
| 341 |
|
|
ll_rw_block (WRITE, 1, &dind_bh);
|
| 342 |
|
|
wait_on_buffer (dind_bh);
|
| 343 |
|
|
}
|
| 344 |
|
|
brelse (dind_bh);
|
| 345 |
|
|
return retry;
|
| 346 |
|
|
}
|
| 347 |
|
|
|
| 348 |
|
|
static int trunc_dindirect_swab32 (struct inode * inode, int offset,
|
| 349 |
|
|
u32 * p)
|
| 350 |
|
|
{
|
| 351 |
|
|
int i, tmp;
|
| 352 |
|
|
struct buffer_head * dind_bh;
|
| 353 |
|
|
u32 * dind;
|
| 354 |
|
|
int retry = 0;
|
| 355 |
|
|
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
|
| 356 |
|
|
int blocks = inode->i_sb->s_blocksize / 512;
|
| 357 |
|
|
int dindirect_block = DINDIRECT_BLOCK;
|
| 358 |
|
|
|
| 359 |
|
|
tmp = swab32(*p);
|
| 360 |
|
|
if (!tmp)
|
| 361 |
|
|
return 0;
|
| 362 |
|
|
dind_bh = bread (inode->i_dev, tmp, inode->i_sb->s_blocksize);
|
| 363 |
|
|
if (tmp != swab32(*p)) {
|
| 364 |
|
|
brelse (dind_bh);
|
| 365 |
|
|
return 1;
|
| 366 |
|
|
}
|
| 367 |
|
|
if (!dind_bh) {
|
| 368 |
|
|
*p = swab32(0);
|
| 369 |
|
|
return 0;
|
| 370 |
|
|
}
|
| 371 |
|
|
repeat:
|
| 372 |
|
|
for (i = dindirect_block ; i < addr_per_block ; i++) {
|
| 373 |
|
|
if (i < 0)
|
| 374 |
|
|
i = 0;
|
| 375 |
|
|
if (i < dindirect_block)
|
| 376 |
|
|
goto repeat;
|
| 377 |
|
|
dind = i + (u32 *) dind_bh->b_data;
|
| 378 |
|
|
tmp = swab32(*dind);
|
| 379 |
|
|
if (!tmp)
|
| 380 |
|
|
continue;
|
| 381 |
|
|
retry |= trunc_indirect_swab32 (inode, offset + (i * addr_per_block),
|
| 382 |
|
|
dind);
|
| 383 |
|
|
mark_buffer_dirty(dind_bh, 1);
|
| 384 |
|
|
}
|
| 385 |
|
|
dind = (u32 *) dind_bh->b_data;
|
| 386 |
|
|
for (i = 0; i < addr_per_block; i++)
|
| 387 |
|
|
if (swab32(*(dind++)))
|
| 388 |
|
|
break;
|
| 389 |
|
|
if (i >= addr_per_block)
|
| 390 |
|
|
if (dind_bh->b_count != 1)
|
| 391 |
|
|
retry = 1;
|
| 392 |
|
|
else {
|
| 393 |
|
|
tmp = swab32(*p);
|
| 394 |
|
|
*p = swab32(0);
|
| 395 |
|
|
inode->i_blocks -= blocks;
|
| 396 |
|
|
inode->i_dirt = 1;
|
| 397 |
|
|
ext2_free_blocks (inode, tmp, 1);
|
| 398 |
|
|
}
|
| 399 |
|
|
if (IS_SYNC(inode) && buffer_dirty(dind_bh)) {
|
| 400 |
|
|
ll_rw_block (WRITE, 1, &dind_bh);
|
| 401 |
|
|
wait_on_buffer (dind_bh);
|
| 402 |
|
|
}
|
| 403 |
|
|
brelse (dind_bh);
|
| 404 |
|
|
return retry;
|
| 405 |
|
|
}
|
| 406 |
|
|
|
| 407 |
|
|
static int trunc_tindirect (struct inode * inode)
|
| 408 |
|
|
{
|
| 409 |
|
|
int i, tmp;
|
| 410 |
|
|
struct buffer_head * tind_bh;
|
| 411 |
|
|
u32 * tind, * p;
|
| 412 |
|
|
int retry = 0;
|
| 413 |
|
|
int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
|
| 414 |
|
|
int blocks = inode->i_sb->s_blocksize / 512;
|
| 415 |
|
|
#define TINDIRECT_BLOCK (((int)DIRECT_BLOCK - (addr_per_block * addr_per_block + \
|
| 416 |
|
|
addr_per_block + EXT2_NDIR_BLOCKS)) / \
|
| 417 |
|
|
(addr_per_block * addr_per_block))
|
| 418 |
|
|
int tindirect_block = TINDIRECT_BLOCK;
|
| 419 |
|
|
|
| 420 |
|
|
p = inode->u.ext2_i.i_data + EXT2_TIND_BLOCK;
|
| 421 |
|
|
if (!(tmp = *p))
|
| 422 |
|
|
return 0;
|
| 423 |
|
|
tind_bh = bread (inode->i_dev, tmp, inode->i_sb->s_blocksize);
|
| 424 |
|
|
if (tmp != *p) {
|
| 425 |
|
|
brelse (tind_bh);
|
| 426 |
|
|
return 1;
|
| 427 |
|
|
}
|
| 428 |
|
|
if (!tind_bh) {
|
| 429 |
|
|
*p = 0;
|
| 430 |
|
|
return 0;
|
| 431 |
|
|
}
|
| 432 |
|
|
repeat:
|
| 433 |
|
|
for (i = tindirect_block ; i < addr_per_block ; i++) {
|
| 434 |
|
|
if (i < 0)
|
| 435 |
|
|
i = 0;
|
| 436 |
|
|
if (i < tindirect_block)
|
| 437 |
|
|
goto repeat;
|
| 438 |
|
|
tind = i + (u32 *) tind_bh->b_data;
|
| 439 |
|
|
retry |= trunc_dindirect_swab32(inode, EXT2_NDIR_BLOCKS +
|
| 440 |
|
|
addr_per_block + (i + 1) * addr_per_block * addr_per_block,
|
| 441 |
|
|
tind);
|
| 442 |
|
|
mark_buffer_dirty(tind_bh, 1);
|
| 443 |
|
|
}
|
| 444 |
|
|
tind = (u32 *) tind_bh->b_data;
|
| 445 |
|
|
for (i = 0; i < addr_per_block; i++)
|
| 446 |
|
|
if (swab32(*(tind++)))
|
| 447 |
|
|
break;
|
| 448 |
|
|
if (i >= addr_per_block)
|
| 449 |
|
|
if (tind_bh->b_count != 1)
|
| 450 |
|
|
retry = 1;
|
| 451 |
|
|
else {
|
| 452 |
|
|
tmp = *p;
|
| 453 |
|
|
*p = 0;
|
| 454 |
|
|
inode->i_blocks -= blocks;
|
| 455 |
|
|
inode->i_dirt = 1;
|
| 456 |
|
|
ext2_free_blocks (inode, tmp, 1);
|
| 457 |
|
|
}
|
| 458 |
|
|
if (IS_SYNC(inode) && buffer_dirty(tind_bh)) {
|
| 459 |
|
|
ll_rw_block (WRITE, 1, &tind_bh);
|
| 460 |
|
|
wait_on_buffer (tind_bh);
|
| 461 |
|
|
}
|
| 462 |
|
|
brelse (tind_bh);
|
| 463 |
|
|
return retry;
|
| 464 |
|
|
}
|
| 465 |
|
|
|
| 466 |
|
|
void ext2_truncate (struct inode * inode)
|
| 467 |
|
|
{
|
| 468 |
|
|
int retry;
|
| 469 |
|
|
struct buffer_head * bh;
|
| 470 |
|
|
int err;
|
| 471 |
|
|
int offset;
|
| 472 |
|
|
|
| 473 |
|
|
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
|
| 474 |
|
|
S_ISLNK(inode->i_mode)))
|
| 475 |
|
|
return;
|
| 476 |
|
|
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
|
| 477 |
|
|
return;
|
| 478 |
|
|
ext2_discard_prealloc(inode);
|
| 479 |
|
|
while (1) {
|
| 480 |
|
|
retry = trunc_direct(inode);
|
| 481 |
|
|
retry |= trunc_indirect (inode, EXT2_IND_BLOCK,
|
| 482 |
|
|
(u32 *) &inode->u.ext2_i.i_data[EXT2_IND_BLOCK]);
|
| 483 |
|
|
retry |= trunc_dindirect (inode, EXT2_IND_BLOCK +
|
| 484 |
|
|
EXT2_ADDR_PER_BLOCK(inode->i_sb),
|
| 485 |
|
|
(u32 *) &inode->u.ext2_i.i_data[EXT2_DIND_BLOCK]);
|
| 486 |
|
|
retry |= trunc_tindirect (inode);
|
| 487 |
|
|
if (!retry)
|
| 488 |
|
|
break;
|
| 489 |
|
|
if (IS_SYNC(inode) && inode->i_dirt)
|
| 490 |
|
|
ext2_sync_inode (inode);
|
| 491 |
|
|
current->counter = 0;
|
| 492 |
|
|
schedule ();
|
| 493 |
|
|
}
|
| 494 |
|
|
/*
|
| 495 |
|
|
* If the file is not being truncated to a block boundary, the
|
| 496 |
|
|
* contents of the partial block following the end of the file must be
|
| 497 |
|
|
* zeroed in case it ever becomes accessible again because of
|
| 498 |
|
|
* subsequent file growth.
|
| 499 |
|
|
*/
|
| 500 |
|
|
offset = inode->i_size & (inode->i_sb->s_blocksize - 1);
|
| 501 |
|
|
if (offset) {
|
| 502 |
|
|
bh = ext2_bread (inode,
|
| 503 |
|
|
inode->i_size >> EXT2_BLOCK_SIZE_BITS(inode->i_sb),
|
| 504 |
|
|
0, &err);
|
| 505 |
|
|
if (bh) {
|
| 506 |
|
|
memset (bh->b_data + offset, 0,
|
| 507 |
|
|
inode->i_sb->s_blocksize - offset);
|
| 508 |
|
|
mark_buffer_dirty (bh, 0);
|
| 509 |
|
|
brelse (bh);
|
| 510 |
|
|
}
|
| 511 |
|
|
}
|
| 512 |
|
|
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
| 513 |
|
|
inode->i_dirt = 1;
|
| 514 |
|
|
}
|
