aboutsummaryrefslogtreecommitdiff
path: root/fs/udf/truncate.c
blob: 6111d97902d756c9cf5fb5ca0bd3f4895a7e6ed7 (plain)
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
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
/*
 * 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 <linux/buffer_head.h>

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

static void extent_trunc(struct inode *inode, struct extent_position *epos,
			 kernel_lb_addr eloc, int8_t etype, uint32_t elen,
			 uint32_t nelen)
{
	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 > 0) {
			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 = {};
	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(short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(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)
				printk(KERN_WARNING
				       "udf_truncate_tail_extent(): Too long "
				       "extent after EOF in inode %u: i_size: "
				       "%Ld lbcount: %Ld 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)
				printk(KERN_ERR "udf_truncate_tail_extent(): "
				       "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} };
	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(short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(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);
}

void udf_truncate_extents(struct inode *inode)
{
	struct extent_position epos;
	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;
	struct udf_sb_info *sbi = UDF_SB(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(short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
		adsize = sizeof(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) {
		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 */
					if (!epos.bh)
						BUG();
					udf_free_blocks(sb, inode, epos.block,
							0, indirect_ext_len);
				} else {
					if (!epos.bh) {
						iinfo->i_lenAlloc =
								lenalloc;
						mark_inode_dirty(inode);
					} else {
						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);
					}
				}
				brelse(epos.bh);
				epos.offset = sizeof(struct allocExtDesc);
				epos.block = eloc;
				epos.bh = udf_tread(sb,
						udf_get_lb_pblock(sb, eloc, 0));
				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) {
			if (!epos.bh)
				BUG();
			udf_free_blocks(sb, inode, epos.block, 0,
					indirect_ext_len);
		} else {
			if (!epos.bh) {
				iinfo->i_lenAlloc = lenalloc;
				mark_inode_dirty(inode);
			} else {
				struct allocExtDesc *aed =
				    (struct allocExtDesc *)(epos.bh->b_data);
				aed->lengthAllocDescs = cpu_to_le32(lenalloc);
				if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) ||
				    sbi->s_udfrev >= 0x0201)
					udf_update_tag(epos.bh->b_data,
						lenalloc +
						sizeof(struct allocExtDesc));
				else
					udf_update_tag(epos.bh->b_data,
						sizeof(struct allocExtDesc));
				mark_buffer_dirty_inode(epos.bh, inode);
			}
		}
	} else if (inode->i_size) {
		if (byte_offset) {
			kernel_long_ad extent;

			/*
			 *  OK, there is not extent covering inode->i_size and
			 *  no extent above inode->i_size => truncate is
			 *  extending the file by 'offset' blocks.
			 */
			if ((!epos.bh &&
			     epos.offset ==
					udf_file_entry_alloc_offset(inode)) ||
			    (epos.bh && epos.offset ==
						sizeof(struct allocExtDesc))) {
				/* File has no extents at all or has empty last
				 * indirect extent! Create a fake extent... */
				extent.extLocation.logicalBlockNum = 0;
				extent.extLocation.partitionReferenceNum = 0;
				extent.extLength =
					EXT_NOT_RECORDED_NOT_ALLOCATED;
			} else {
				epos.offset -= adsize;
				etype = udf_next_aext(inode, &epos,
						      &extent.extLocation,
						      &extent.extLength, 0);
				extent.extLength |= etype << 30;
			}
			udf_extend_file(inode, &epos, &extent,
					offset +
					((inode->i_size &
						(sb->s_blocksize - 1)) != 0));
		}
	}
	iinfo->i_lenExtents = inode->i_size;

	brelse(epos.bh);
}