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/buffer_head.h>
26
27 #include "udf_i.h"
28 #include "udf_sb.h"
29
extent_trunc(struct inode * inode,struct extent_position * epos,struct kernel_lb_addr * eloc,int8_t etype,uint32_t elen,uint32_t nelen)30 static void extent_trunc(struct inode *inode, struct extent_position *epos,
31 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
32 uint32_t nelen)
33 {
34 struct kernel_lb_addr neloc = {};
35 int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
36 inode->i_sb->s_blocksize_bits;
37 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
38 inode->i_sb->s_blocksize_bits;
39
40 if (nelen) {
41 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
42 udf_free_blocks(inode->i_sb, inode, eloc, 0,
43 last_block);
44 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
45 } else
46 neloc = *eloc;
47 nelen = (etype << 30) | nelen;
48 }
49
50 if (elen != nelen) {
51 udf_write_aext(inode, epos, &neloc, nelen, 0);
52 if (last_block - first_block > 0) {
53 if (etype == (EXT_RECORDED_ALLOCATED >> 30))
54 mark_inode_dirty(inode);
55
56 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
57 udf_free_blocks(inode->i_sb, inode, eloc,
58 first_block,
59 last_block - first_block);
60 }
61 }
62 }
63
64 /*
65 * Truncate the last extent to match i_size. This function assumes
66 * that preallocation extent is already truncated.
67 */
udf_truncate_tail_extent(struct inode * inode)68 void udf_truncate_tail_extent(struct inode *inode)
69 {
70 struct extent_position epos = {};
71 struct kernel_lb_addr eloc;
72 uint32_t elen, nelen;
73 uint64_t lbcount = 0;
74 int8_t etype = -1, netype;
75 int adsize;
76 struct udf_inode_info *iinfo = UDF_I(inode);
77
78 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
79 inode->i_size == iinfo->i_lenExtents)
80 return;
81 /* Are we going to delete the file anyway? */
82 if (inode->i_nlink == 0)
83 return;
84
85 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
86 adsize = sizeof(struct short_ad);
87 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
88 adsize = sizeof(struct long_ad);
89 else
90 BUG();
91
92 /* Find the last extent in the file */
93 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
94 etype = netype;
95 lbcount += elen;
96 if (lbcount > inode->i_size) {
97 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
98 udf_warn(inode->i_sb,
99 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
100 (unsigned)inode->i_ino,
101 (long long)inode->i_size,
102 (long long)lbcount,
103 (unsigned)eloc.logicalBlockNum,
104 (unsigned)elen);
105 nelen = elen - (lbcount - inode->i_size);
106 epos.offset -= adsize;
107 extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
108 epos.offset += adsize;
109 if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
110 udf_err(inode->i_sb,
111 "Extent after EOF in inode %u\n",
112 (unsigned)inode->i_ino);
113 break;
114 }
115 }
116 /* This inode entry is in-memory only and thus we don't have to mark
117 * the inode dirty */
118 iinfo->i_lenExtents = inode->i_size;
119 brelse(epos.bh);
120 }
121
udf_discard_prealloc(struct inode * inode)122 void udf_discard_prealloc(struct inode *inode)
123 {
124 struct extent_position epos = { NULL, 0, {0, 0} };
125 struct kernel_lb_addr eloc;
126 uint32_t elen;
127 uint64_t lbcount = 0;
128 int8_t etype = -1, netype;
129 int adsize;
130 struct udf_inode_info *iinfo = UDF_I(inode);
131
132 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
133 inode->i_size == iinfo->i_lenExtents)
134 return;
135
136 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
137 adsize = sizeof(struct short_ad);
138 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
139 adsize = sizeof(struct long_ad);
140 else
141 adsize = 0;
142
143 epos.block = iinfo->i_location;
144
145 /* Find the last extent in the file */
146 while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
147 etype = netype;
148 lbcount += elen;
149 }
150 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
151 epos.offset -= adsize;
152 lbcount -= elen;
153 extent_trunc(inode, &epos, &eloc, etype, elen, 0);
154 if (!epos.bh) {
155 iinfo->i_lenAlloc =
156 epos.offset -
157 udf_file_entry_alloc_offset(inode);
158 mark_inode_dirty(inode);
159 } else {
160 struct allocExtDesc *aed =
161 (struct allocExtDesc *)(epos.bh->b_data);
162 aed->lengthAllocDescs =
163 cpu_to_le32(epos.offset -
164 sizeof(struct allocExtDesc));
165 if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
166 UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
167 udf_update_tag(epos.bh->b_data, epos.offset);
168 else
169 udf_update_tag(epos.bh->b_data,
170 sizeof(struct allocExtDesc));
171 mark_buffer_dirty_inode(epos.bh, inode);
172 }
173 }
174 /* This inode entry is in-memory only and thus we don't have to mark
175 * the inode dirty */
176 iinfo->i_lenExtents = lbcount;
177 brelse(epos.bh);
178 }
179
udf_update_alloc_ext_desc(struct inode * inode,struct extent_position * epos,u32 lenalloc)180 static void udf_update_alloc_ext_desc(struct inode *inode,
181 struct extent_position *epos,
182 u32 lenalloc)
183 {
184 struct super_block *sb = inode->i_sb;
185 struct udf_sb_info *sbi = UDF_SB(sb);
186
187 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
188 int len = sizeof(struct allocExtDesc);
189
190 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
191 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
192 len += lenalloc;
193
194 udf_update_tag(epos->bh->b_data, len);
195 mark_buffer_dirty_inode(epos->bh, inode);
196 }
197
198 /*
199 * Truncate extents of inode to inode->i_size. This function can be used only
200 * for making file shorter. For making file longer, udf_extend_file() has to
201 * be used.
202 */
udf_truncate_extents(struct inode * inode)203 void udf_truncate_extents(struct inode *inode)
204 {
205 struct extent_position epos;
206 struct kernel_lb_addr eloc, neloc = {};
207 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
208 int8_t etype;
209 struct super_block *sb = inode->i_sb;
210 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
211 loff_t byte_offset;
212 int adsize;
213 struct udf_inode_info *iinfo = UDF_I(inode);
214
215 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
216 adsize = sizeof(struct short_ad);
217 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
218 adsize = sizeof(struct long_ad);
219 else
220 BUG();
221
222 etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
223 byte_offset = (offset << sb->s_blocksize_bits) +
224 (inode->i_size & (sb->s_blocksize - 1));
225 if (etype == -1) {
226 /* We should extend the file? */
227 WARN_ON(byte_offset);
228 return;
229 }
230 epos.offset -= adsize;
231 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
232 epos.offset += adsize;
233 if (byte_offset)
234 lenalloc = epos.offset;
235 else
236 lenalloc = epos.offset - adsize;
237
238 if (!epos.bh)
239 lenalloc -= udf_file_entry_alloc_offset(inode);
240 else
241 lenalloc -= sizeof(struct allocExtDesc);
242
243 while ((etype = udf_current_aext(inode, &epos, &eloc,
244 &elen, 0)) != -1) {
245 if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
246 udf_write_aext(inode, &epos, &neloc, nelen, 0);
247 if (indirect_ext_len) {
248 /* We managed to free all extents in the
249 * indirect extent - free it too */
250 BUG_ON(!epos.bh);
251 udf_free_blocks(sb, inode, &epos.block,
252 0, indirect_ext_len);
253 } else if (!epos.bh) {
254 iinfo->i_lenAlloc = lenalloc;
255 mark_inode_dirty(inode);
256 } else
257 udf_update_alloc_ext_desc(inode,
258 &epos, lenalloc);
259 brelse(epos.bh);
260 epos.offset = sizeof(struct allocExtDesc);
261 epos.block = eloc;
262 epos.bh = udf_tread(sb,
263 udf_get_lb_pblock(sb, &eloc, 0));
264 if (elen)
265 indirect_ext_len =
266 (elen + sb->s_blocksize - 1) >>
267 sb->s_blocksize_bits;
268 else
269 indirect_ext_len = 1;
270 } else {
271 extent_trunc(inode, &epos, &eloc, etype, elen, 0);
272 epos.offset += adsize;
273 }
274 }
275
276 if (indirect_ext_len) {
277 BUG_ON(!epos.bh);
278 udf_free_blocks(sb, inode, &epos.block, 0, indirect_ext_len);
279 } else if (!epos.bh) {
280 iinfo->i_lenAlloc = lenalloc;
281 mark_inode_dirty(inode);
282 } else
283 udf_update_alloc_ext_desc(inode, &epos, lenalloc);
284 iinfo->i_lenExtents = inode->i_size;
285
286 brelse(epos.bh);
287 }
288