File: truncate.c

package info (click to toggle)
linux 4.19.37-3
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 962,264 kB
  • sloc: ansic: 16,757,120; asm: 271,404; makefile: 38,285; sh: 33,529; perl: 27,681; python: 21,031; cpp: 5,063; yacc: 4,648; lex: 2,585; awk: 1,385; ruby: 25; sed: 5
file content (289 lines) | stat: -rw-r--r-- 8,103 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
/*
 * truncate.c
 *
 * PURPOSE
 *	Truncate handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 *
 *  (C) 1999-2004 Ben Fennema
 *  (C) 1999 Stelias Computing Inc
 *
 * HISTORY
 *
 *  02/24/99 blf  Created.
 *
 */

#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/mm.h>

#include "udf_i.h"
#include "udf_sb.h"

static void extent_trunc(struct inode *inode, struct extent_position *epos,
			 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
			 uint32_t nelen)
{
	struct kernel_lb_addr neloc = {};
	int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
		inode->i_sb->s_blocksize_bits;
	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
		inode->i_sb->s_blocksize_bits;

	if (nelen) {
		if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
			udf_free_blocks(inode->i_sb, inode, eloc, 0,
					last_block);
			etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
		} else
			neloc = *eloc;
		nelen = (etype << 30) | nelen;
	}

	if (elen != nelen) {
		udf_write_aext(inode, epos, &neloc, nelen, 0);
		if (last_block > first_block) {
			if (etype == (EXT_RECORDED_ALLOCATED >> 30))
				mark_inode_dirty(inode);

			if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
				udf_free_blocks(inode->i_sb, inode, eloc,
						first_block,
						last_block - first_block);
		}
	}
}

/*
 * Truncate the last extent to match i_size. This function assumes
 * that preallocation extent is already truncated.
 */
void udf_truncate_tail_extent(struct inode *inode)
{
	struct extent_position epos = {};
	struct kernel_lb_addr eloc;
	uint32_t elen, nelen;
	uint64_t lbcount = 0;
	int8_t etype = -1, netype;
	int adsize;
	struct udf_inode_info *iinfo = UDF_I(inode);

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
	    inode->i_size == iinfo->i_lenExtents)
		return;
	/* Are we going to delete the file anyway? */
	if (inode->i_nlink == 0)
		return;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
		adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(struct long_ad);
	else
		BUG();

	/* Find the last extent in the file */
	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
		etype = netype;
		lbcount += elen;
		if (lbcount > inode->i_size) {
			if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
				udf_warn(inode->i_sb,
					 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
					 (unsigned)inode->i_ino,
					 (long long)inode->i_size,
					 (long long)lbcount,
					 (unsigned)eloc.logicalBlockNum,
					 (unsigned)elen);
			nelen = elen - (lbcount - inode->i_size);
			epos.offset -= adsize;
			extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
			epos.offset += adsize;
			if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
				udf_err(inode->i_sb,
					"Extent after EOF in inode %u\n",
					(unsigned)inode->i_ino);
			break;
		}
	}
	/* This inode entry is in-memory only and thus we don't have to mark
	 * the inode dirty */
	iinfo->i_lenExtents = inode->i_size;
	brelse(epos.bh);
}

void udf_discard_prealloc(struct inode *inode)
{
	struct extent_position epos = { NULL, 0, {0, 0} };
	struct kernel_lb_addr eloc;
	uint32_t elen;
	uint64_t lbcount = 0;
	int8_t etype = -1, netype;
	int adsize;
	struct udf_inode_info *iinfo = UDF_I(inode);

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
	    inode->i_size == iinfo->i_lenExtents)
		return;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
		adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(struct long_ad);
	else
		adsize = 0;

	epos.block = iinfo->i_location;

	/* Find the last extent in the file */
	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
		etype = netype;
		lbcount += elen;
	}
	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
		epos.offset -= adsize;
		lbcount -= elen;
		extent_trunc(inode, &epos, &eloc, etype, elen, 0);
		if (!epos.bh) {
			iinfo->i_lenAlloc =
				epos.offset -
				udf_file_entry_alloc_offset(inode);
			mark_inode_dirty(inode);
		} else {
			struct allocExtDesc *aed =
				(struct allocExtDesc *)(epos.bh->b_data);
			aed->lengthAllocDescs =
				cpu_to_le32(epos.offset -
					    sizeof(struct allocExtDesc));
			if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
			    UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
				udf_update_tag(epos.bh->b_data, epos.offset);
			else
				udf_update_tag(epos.bh->b_data,
					       sizeof(struct allocExtDesc));
			mark_buffer_dirty_inode(epos.bh, inode);
		}
	}
	/* This inode entry is in-memory only and thus we don't have to mark
	 * the inode dirty */
	iinfo->i_lenExtents = lbcount;
	brelse(epos.bh);
}

static void udf_update_alloc_ext_desc(struct inode *inode,
				      struct extent_position *epos,
				      u32 lenalloc)
{
	struct super_block *sb = inode->i_sb;
	struct udf_sb_info *sbi = UDF_SB(sb);

	struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
	int len = sizeof(struct allocExtDesc);

	aed->lengthAllocDescs =	cpu_to_le32(lenalloc);
	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
		len += lenalloc;

	udf_update_tag(epos->bh->b_data, len);
	mark_buffer_dirty_inode(epos->bh, inode);
}

/*
 * Truncate extents of inode to inode->i_size. This function can be used only
 * for making file shorter. For making file longer, udf_extend_file() has to
 * be used.
 */
void udf_truncate_extents(struct inode *inode)
{
	struct extent_position epos;
	struct kernel_lb_addr eloc, neloc = {};
	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
	int8_t etype;
	struct super_block *sb = inode->i_sb;
	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
	loff_t byte_offset;
	int adsize;
	struct udf_inode_info *iinfo = UDF_I(inode);

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
		adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(struct long_ad);
	else
		BUG();

	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
	byte_offset = (offset << sb->s_blocksize_bits) +
		(inode->i_size & (sb->s_blocksize - 1));
	if (etype == -1) {
		/* We should extend the file? */
		WARN_ON(byte_offset);
		return;
	}
	epos.offset -= adsize;
	extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
	epos.offset += adsize;
	if (byte_offset)
		lenalloc = epos.offset;
	else
		lenalloc = epos.offset - adsize;

	if (!epos.bh)
		lenalloc -= udf_file_entry_alloc_offset(inode);
	else
		lenalloc -= sizeof(struct allocExtDesc);

	while ((etype = udf_current_aext(inode, &epos, &eloc,
					 &elen, 0)) != -1) {
		if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
			udf_write_aext(inode, &epos, &neloc, nelen, 0);
			if (indirect_ext_len) {
				/* We managed to free all extents in the
				 * indirect extent - free it too */
				BUG_ON(!epos.bh);
				udf_free_blocks(sb, NULL, &epos.block,
						0, indirect_ext_len);
			} else if (!epos.bh) {
				iinfo->i_lenAlloc = lenalloc;
				mark_inode_dirty(inode);
			} else
				udf_update_alloc_ext_desc(inode,
						&epos, lenalloc);
			brelse(epos.bh);
			epos.offset = sizeof(struct allocExtDesc);
			epos.block = eloc;
			epos.bh = udf_tread(sb,
					udf_get_lb_pblock(sb, &eloc, 0));
			/* Error reading indirect block? */
			if (!epos.bh)
				return;
			if (elen)
				indirect_ext_len =
					(elen + sb->s_blocksize - 1) >>
					sb->s_blocksize_bits;
			else
				indirect_ext_len = 1;
		} else {
			extent_trunc(inode, &epos, &eloc, etype, elen, 0);
			epos.offset += adsize;
		}
	}

	if (indirect_ext_len) {
		BUG_ON(!epos.bh);
		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
	} else if (!epos.bh) {
		iinfo->i_lenAlloc = lenalloc;
		mark_inode_dirty(inode);
	} else
		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
	iinfo->i_lenExtents = inode->i_size;

	brelse(epos.bh);
}