1 /*
2 * truncate.c
3 *
4 * PURPOSE
5 * Truncate handling routines for the OSTA-UDF(tm) filesystem.
6 *
7 * COPYRIGHT
8 * This file is distributed under the terms of the GNU General Public
9 * License (GPL). Copies of the GPL can be obtained from:
10 * ftp://prep.ai.mit.edu/pub/gnu/GPL
11 * Each contributing author retains all rights to their own work.
12 *
13 * (C) 1999-2004 Ben Fennema
14 * (C) 1999 Stelias Computing Inc
15 *
16 * HISTORY
17 *
18 * 02/24/99 blf Created.
19 *
20 */
21
22 #include "udfdecl.h"
23 #include <linux/fs.h>
24 #include <linux/mm.h>
25 #include <linux/udf_fs.h>
26 #include <linux/buffer_head.h>
27
28 #include "udf_i.h"
29 #include "udf_sb.h"
30
31 static void extent_trunc(struct inode *inode, struct extent_position *epos,
32 kernel_lb_addr eloc, int8_t etype, uint32_t elen,
33 uint32_t nelen)
34 {
35 kernel_lb_addr neloc = {};
36 int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
37 inode->i_sb->s_blocksize_bits;
38 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
39 inode->i_sb->s_blocksize_bits;
40
41 if (nelen) {
42 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
43 udf_free_blocks(inode->i_sb, inode, eloc, 0,
44 last_block);
45 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
46 } else
47 neloc = eloc;
48 nelen = (etype << 30) | nelen;
49 }
50
51 if (elen != nelen) {
52 udf_write_aext(inode, epos, neloc, nelen, 0);
53 if (last_block - first_block > 0) {
54 if (etype == (EXT_RECORDED_ALLOCATED >> 30))
55 mark_inode_dirty(inode);
56
57 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
58 udf_free_blocks(inode->i_sb, inode, eloc,
59 first_block,
60 last_block - first_block);
61 }
62 }
63 }
64
65 /*
66 * Truncate the last extent to match i_size. This function assumes
67 * that preallocation extent is already truncated.
68 */
69 void udf_truncate_tail_extent(struct inode *inode)
70 {
71 struct extent_position epos = {};
72 kernel_lb_addr eloc;
73 uint32_t elen, nelen;
74 uint64_t lbcount = 0;
75 int8_t etype = -1, netype;
76 int adsize;
77 struct udf_inode_info *iinfo = UDF_I(inode);
78
79 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
80 inode->i_size == iinfo->i_lenExtents)
81 return;
82 /* Are we going to delete the file anyway? */
83 if (inode->i_nlink == 0)
84 return;
85
86 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
87 adsize = sizeof(short_ad);
88 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
89 adsize = sizeof(long_ad);
90 else
91 BUG();
92
93 /* Find the last extent in the file */
94 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
95 etype = netype;
96 lbcount += elen;
97 if (lbcount > inode->i_size) {
98 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
99 printk(KERN_WARNING
100 "udf_truncate_tail_extent(): Too long "
101 "extent after EOF in inode %u: i_size: "
102 "%Ld lbcount: %Ld extent %u+%u\n",
103 (unsigned)inode->i_ino,
104 (long long)inode->i_size,
105 (long long)lbcount,
106 (unsigned)eloc.logicalBlockNum,
107 (unsigned)elen);
108 nelen = elen - (lbcount - inode->i_size);
109 epos.offset -= adsize;
110 extent_trunc(inode, &epos, eloc, etype, elen, nelen);
111 epos.offset += adsize;
112 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
113 printk(KERN_ERR "udf_truncate_tail_extent(): "
114 "Extent after EOF in inode %u.\n",
115 (unsigned)inode->i_ino);
116 break;
117 }
118 }
119 /* This inode entry is in-memory only and thus we don't have to mark
120 * the inode dirty */
121 iinfo->i_lenExtents = inode->i_size;
122 brelse(epos.bh);
123 }
124
125 void udf_discard_prealloc(struct inode *inode)
126 {
127 struct extent_position epos = { NULL, 0, {0, 0} };
128 kernel_lb_addr eloc;
129 uint32_t elen;
130 uint64_t lbcount = 0;
131 int8_t etype = -1, netype;
132 int adsize;
133 struct udf_inode_info *iinfo = UDF_I(inode);
134
135 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
136 inode->i_size == iinfo->i_lenExtents)
137 return;
138
139 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
140 adsize = sizeof(short_ad);
141 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
142 adsize = sizeof(long_ad);
143 else
144 adsize = 0;
145
146 epos.block = iinfo->i_location;
147
148 /* Find the last extent in the file */
149 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
150 etype = netype;
151 lbcount += elen;
152 }
153 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
154 epos.offset -= adsize;
155 lbcount -= elen;
156 extent_trunc(inode, &epos, eloc, etype, elen, 0);
157 if (!epos.bh) {
158 iinfo->i_lenAlloc =
159 epos.offset -
160 udf_file_entry_alloc_offset(inode);
161 mark_inode_dirty(inode);
162 } else {
163 struct allocExtDesc *aed =
164 (struct allocExtDesc *)(epos.bh->b_data);
165 aed->lengthAllocDescs =
166 cpu_to_le32(epos.offset -
167 sizeof(struct allocExtDesc));
168 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
169 UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
170 udf_update_tag(epos.bh->b_data, epos.offset);
171 else
172 udf_update_tag(epos.bh->b_data,
173 sizeof(struct allocExtDesc));
174 mark_buffer_dirty_inode(epos.bh, inode);
175 }
176 }
177 /* This inode entry is in-memory only and thus we don't have to mark
178 * the inode dirty */
179 iinfo->i_lenExtents = lbcount;
180 brelse(epos.bh);
181 }
182
183 void udf_truncate_extents(struct inode *inode)
184 {
185 struct extent_position epos;
186 kernel_lb_addr eloc, neloc = {};
187 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
188 int8_t etype;
189 struct super_block *sb = inode->i_sb;
190 struct udf_sb_info *sbi = UDF_SB(sb);
191 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
192 loff_t byte_offset;
193 int adsize;
194 struct udf_inode_info *iinfo = UDF_I(inode);
195
196 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
197 adsize = sizeof(short_ad);
198 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
199 adsize = sizeof(long_ad);
200 else
201 BUG();
202
203 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
204 byte_offset = (offset << sb->s_blocksize_bits) +
205 (inode->i_size & (sb->s_blocksize - 1));
206 if (etype != -1) {
207 epos.offset -= adsize;
208 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
209 epos.offset += adsize;
210 if (byte_offset)
211 lenalloc = epos.offset;
212 else
213 lenalloc = epos.offset - adsize;
214
215 if (!epos.bh)
216 lenalloc -= udf_file_entry_alloc_offset(inode);
217 else
218 lenalloc -= sizeof(struct allocExtDesc);
219
220 while ((etype = udf_current_aext(inode, &epos, &eloc,
221 &elen, 0)) != -1) {
222 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
223 udf_write_aext(inode, &epos, neloc, nelen, 0);
224 if (indirect_ext_len) {
225 /* We managed to free all extents in the
226 * indirect extent - free it too */
227 if (!epos.bh)
228 BUG();
229 udf_free_blocks(sb, inode, epos.block,
230 0, indirect_ext_len);
231 } else {
232 if (!epos.bh) {
233 iinfo->i_lenAlloc =
234 lenalloc;
235 mark_inode_dirty(inode);
236 } else {
237 struct allocExtDesc *aed =
238 (struct allocExtDesc *)
239 (epos.bh->b_data);
240 int len =
241 sizeof(struct allocExtDesc);
242
243 aed->lengthAllocDescs =
244 cpu_to_le32(lenalloc);
245 if (!UDF_QUERY_FLAG(sb,
246 UDF_FLAG_STRICT) ||
247 sbi->s_udfrev >= 0x0201)
248 len += lenalloc;
249
250 udf_update_tag(epos.bh->b_data,
251 len);
252 mark_buffer_dirty_inode(
253 epos.bh, inode);
254 }
255 }
256 brelse(epos.bh);
257 epos.offset = sizeof(struct allocExtDesc);
258 epos.block = eloc;
259 epos.bh = udf_tread(sb,
260 udf_get_lb_pblock(sb, eloc, 0));
261 if (elen)
262 indirect_ext_len =
263 (elen + sb->s_blocksize - 1) >>
264 sb->s_blocksize_bits;
265 else
266 indirect_ext_len = 1;
267 } else {
268 extent_trunc(inode, &epos, eloc, etype,
269 elen, 0);
270 epos.offset += adsize;
271 }
272 }
273
274 if (indirect_ext_len) {
275 if (!epos.bh)
276 BUG();
277 udf_free_blocks(sb, inode, epos.block, 0,
278 indirect_ext_len);
279 } else {
280 if (!epos.bh) {
281 iinfo->i_lenAlloc = lenalloc;
282 mark_inode_dirty(inode);
283 } else {
284 struct allocExtDesc *aed =
285 (struct allocExtDesc *)(epos.bh->b_data);
286 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
287 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) ||
288 sbi->s_udfrev >= 0x0201)
289 udf_update_tag(epos.bh->b_data,
290 lenalloc +
291 sizeof(struct allocExtDesc));
292 else
293 udf_update_tag(epos.bh->b_data,
294 sizeof(struct allocExtDesc));
295 mark_buffer_dirty_inode(epos.bh, inode);
296 }
297 }
298 } else if (inode->i_size) {
299 if (byte_offset) {
300 kernel_long_ad extent;
301
302 /*
303 * OK, there is not extent covering inode->i_size and
304 * no extent above inode->i_size => truncate is
305 * extending the file by 'offset' blocks.
306 */
307 if ((!epos.bh &&
308 epos.offset ==
309 udf_file_entry_alloc_offset(inode)) ||
310 (epos.bh && epos.offset ==
311 sizeof(struct allocExtDesc))) {
312 /* File has no extents at all or has empty last
313 * indirect extent! Create a fake extent... */
314 extent.extLocation.logicalBlockNum = 0;
315 extent.extLocation.partitionReferenceNum = 0;
316 extent.extLength =
317 EXT_NOT_RECORDED_NOT_ALLOCATED;
318 } else {
319 epos.offset -= adsize;
320 etype = udf_next_aext(inode, &epos,
321 &extent.extLocation,
322 &extent.extLength, 0);
323 extent.extLength |= etype << 30;
324 }
325 udf_extend_file(inode, &epos, &extent,
326 offset +
327 ((inode->i_size &
328 (sb->s_blocksize - 1)) != 0));
329 }
330 }
331 iinfo->i_lenExtents = inode->i_size;
332
333 brelse(epos.bh);
334 }
335
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