1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * truncate.c
4 *
5 * PURPOSE
6 * Truncate handling routines for the OSTA-UDF(tm) filesystem.
7 *
8 * COPYRIGHT
9 * (C) 1999-2004 Ben Fennema
10 * (C) 1999 Stelias Computing Inc
11 *
12 * HISTORY
13 *
14 * 02/24/99 blf Created.
15 *
16 */
17
18 #include "udfdecl.h"
19 #include <linux/fs.h>
20 #include <linux/mm.h>
21
22 #include "udf_i.h"
23 #include "udf_sb.h"
24
extent_trunc(struct inode * inode,struct extent_position * epos,struct kernel_lb_addr * eloc,int8_t etype,uint32_t elen,uint32_t nelen)25 static void extent_trunc(struct inode *inode, struct extent_position *epos,
26 struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
27 uint32_t nelen)
28 {
29 struct kernel_lb_addr neloc = {};
30 int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
31 inode->i_sb->s_blocksize_bits;
32 int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
33 inode->i_sb->s_blocksize_bits;
34
35 if (nelen) {
36 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
37 udf_free_blocks(inode->i_sb, inode, eloc, 0,
38 last_block);
39 etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
40 } else
41 neloc = *eloc;
42 nelen = (etype << 30) | nelen;
43 }
44
45 if (elen != nelen) {
46 udf_write_aext(inode, epos, &neloc, nelen, 0);
47 if (last_block > first_block) {
48 if (etype == (EXT_RECORDED_ALLOCATED >> 30))
49 mark_inode_dirty(inode);
50
51 if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
52 udf_free_blocks(inode->i_sb, inode, eloc,
53 first_block,
54 last_block - first_block);
55 }
56 }
57 }
58
59 /*
60 * Truncate the last extent to match i_size. This function assumes
61 * that preallocation extent is already truncated.
62 */
udf_truncate_tail_extent(struct inode * inode)63 void udf_truncate_tail_extent(struct inode *inode)
64 {
65 struct extent_position epos = {};
66 struct kernel_lb_addr eloc;
67 uint32_t elen, nelen;
68 uint64_t lbcount = 0;
69 int8_t etype = -1, netype;
70 int adsize;
71 struct udf_inode_info *iinfo = UDF_I(inode);
72 int ret;
73
74 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
75 inode->i_size == iinfo->i_lenExtents)
76 return;
77 /* Are we going to delete the file anyway? */
78 if (inode->i_nlink == 0)
79 return;
80
81 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
82 adsize = sizeof(struct short_ad);
83 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
84 adsize = sizeof(struct long_ad);
85 else
86 BUG();
87
88 /* Find the last extent in the file */
89 while (1) {
90 ret = udf_next_aext(inode, &epos, &eloc, &elen, &netype, 1);
91 if (ret <= 0)
92 break;
93 etype = netype;
94 lbcount += elen;
95 if (lbcount > inode->i_size) {
96 if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
97 udf_warn(inode->i_sb,
98 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
99 (unsigned)inode->i_ino,
100 (long long)inode->i_size,
101 (long long)lbcount,
102 (unsigned)eloc.logicalBlockNum,
103 (unsigned)elen);
104 nelen = elen - (lbcount - inode->i_size);
105 epos.offset -= adsize;
106 extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
107 epos.offset += adsize;
108 if (udf_next_aext(inode, &epos, &eloc, &elen,
109 &netype, 1) > 0)
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 if (ret == 0)
119 iinfo->i_lenExtents = inode->i_size;
120 brelse(epos.bh);
121 }
122
udf_discard_prealloc(struct inode * inode)123 void udf_discard_prealloc(struct inode *inode)
124 {
125 struct extent_position epos = {};
126 struct extent_position prev_epos = {};
127 struct kernel_lb_addr eloc;
128 uint32_t elen;
129 uint64_t lbcount = 0;
130 int8_t etype = -1;
131 struct udf_inode_info *iinfo = UDF_I(inode);
132 int bsize = i_blocksize(inode);
133 int8_t tmpetype = -1;
134 int ret;
135
136 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
137 ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
138 return;
139
140 epos.block = iinfo->i_location;
141
142 /* Find the last extent in the file */
143 while (1) {
144 ret = udf_next_aext(inode, &epos, &eloc, &elen, &tmpetype, 0);
145 if (ret < 0)
146 goto out;
147 if (ret == 0)
148 break;
149 brelse(prev_epos.bh);
150 prev_epos = epos;
151 if (prev_epos.bh)
152 get_bh(prev_epos.bh);
153
154 ret = udf_next_aext(inode, &epos, &eloc, &elen, &etype, 1);
155 if (ret < 0)
156 goto out;
157 lbcount += elen;
158 }
159
160 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
161 lbcount -= elen;
162 udf_delete_aext(inode, prev_epos);
163 udf_free_blocks(inode->i_sb, inode, &eloc, 0,
164 DIV_ROUND_UP(elen, bsize));
165 }
166 /* This inode entry is in-memory only and thus we don't have to mark
167 * the inode dirty */
168 iinfo->i_lenExtents = lbcount;
169 out:
170 brelse(epos.bh);
171 brelse(prev_epos.bh);
172 }
173
udf_update_alloc_ext_desc(struct inode * inode,struct extent_position * epos,u32 lenalloc)174 static void udf_update_alloc_ext_desc(struct inode *inode,
175 struct extent_position *epos,
176 u32 lenalloc)
177 {
178 struct super_block *sb = inode->i_sb;
179 struct udf_sb_info *sbi = UDF_SB(sb);
180
181 struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
182 int len = sizeof(struct allocExtDesc);
183
184 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
185 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
186 len += lenalloc;
187
188 udf_update_tag(epos->bh->b_data, len);
189 mark_buffer_dirty_inode(epos->bh, inode);
190 }
191
192 /*
193 * Truncate extents of inode to inode->i_size. This function can be used only
194 * for making file shorter. For making file longer, udf_extend_file() has to
195 * be used.
196 */
udf_truncate_extents(struct inode * inode)197 int udf_truncate_extents(struct inode *inode)
198 {
199 struct extent_position epos;
200 struct kernel_lb_addr eloc, neloc = {};
201 uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
202 int8_t etype;
203 struct super_block *sb = inode->i_sb;
204 sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
205 loff_t byte_offset;
206 int adsize;
207 struct udf_inode_info *iinfo = UDF_I(inode);
208 int ret = 0;
209
210 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
211 adsize = sizeof(struct short_ad);
212 else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
213 adsize = sizeof(struct long_ad);
214 else
215 BUG();
216
217 ret = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset, &etype);
218 if (ret < 0)
219 return ret;
220 byte_offset = (offset << sb->s_blocksize_bits) +
221 (inode->i_size & (sb->s_blocksize - 1));
222 if (ret == 0) {
223 /* We should extend the file? */
224 WARN_ON(byte_offset);
225 return 0;
226 }
227 epos.offset -= adsize;
228 extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
229 epos.offset += adsize;
230 if (byte_offset)
231 lenalloc = epos.offset;
232 else
233 lenalloc = epos.offset - adsize;
234
235 if (!epos.bh)
236 lenalloc -= udf_file_entry_alloc_offset(inode);
237 else
238 lenalloc -= sizeof(struct allocExtDesc);
239
240 while ((ret = udf_current_aext(inode, &epos, &eloc,
241 &elen, &etype, 0)) > 0) {
242 if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
243 udf_write_aext(inode, &epos, &neloc, nelen, 0);
244 if (indirect_ext_len) {
245 /* We managed to free all extents in the
246 * indirect extent - free it too */
247 BUG_ON(!epos.bh);
248 udf_free_blocks(sb, NULL, &epos.block,
249 0, indirect_ext_len);
250 } else if (!epos.bh) {
251 iinfo->i_lenAlloc = lenalloc;
252 mark_inode_dirty(inode);
253 } else
254 udf_update_alloc_ext_desc(inode,
255 &epos, lenalloc);
256 brelse(epos.bh);
257 epos.offset = sizeof(struct allocExtDesc);
258 epos.block = eloc;
259 epos.bh = sb_bread(sb,
260 udf_get_lb_pblock(sb, &eloc, 0));
261 /* Error reading indirect block? */
262 if (!epos.bh)
263 return -EIO;
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 (ret < 0) {
277 brelse(epos.bh);
278 return ret;
279 }
280
281 if (indirect_ext_len) {
282 BUG_ON(!epos.bh);
283 udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
284 } else if (!epos.bh) {
285 iinfo->i_lenAlloc = lenalloc;
286 mark_inode_dirty(inode);
287 } else
288 udf_update_alloc_ext_desc(inode, &epos, lenalloc);
289 iinfo->i_lenExtents = inode->i_size;
290
291 brelse(epos.bh);
292 return 0;
293 }
294