1 /*
2 * linux/fs/ufs/truncate.c
3 *
4 * Copyright (C) 1998
5 * Daniel Pirkl <daniel.pirkl@email.cz>
6 * Charles University, Faculty of Mathematics and Physics
7 *
8 * from
9 *
10 * linux/fs/ext2/truncate.c
11 *
12 * Copyright (C) 1992, 1993, 1994, 1995
13 * Remy Card (card@masi.ibp.fr)
14 * Laboratoire MASI - Institut Blaise Pascal
15 * Universite Pierre et Marie Curie (Paris VI)
16 *
17 * from
18 *
19 * linux/fs/minix/truncate.c
20 *
21 * Copyright (C) 1991, 1992 Linus Torvalds
22 *
23 * Big-endian to little-endian byte-swapping/bitmaps by
24 * David S. Miller (davem@caip.rutgers.edu), 1995
25 */
26
27 /*
28 * Real random numbers for secure rm added 94/02/18
29 * Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
30 */
31
32 #include <linux/errno.h>
33 #include <linux/fs.h>
34 #include <linux/ufs_fs.h>
35 #include <linux/fcntl.h>
36 #include <linux/sched.h>
37 #include <linux/stat.h>
38 #include <linux/locks.h>
39 #include <linux/string.h>
40
41 #include "swab.h"
42 #include "util.h"
43
44 #undef UFS_TRUNCATE_DEBUG
45
46 #ifdef UFS_TRUNCATE_DEBUG
47 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
48 #else
49 #define UFSD(x)
50 #endif
51
52 /*
53 * Secure deletion currently doesn't work. It interacts very badly
54 * with buffers shared with memory mappings, and for that reason
55 * can't be done in the truncate() routines. It should instead be
56 * done separately in "release()" before calling the truncate routines
57 * that will release the actual file blocks.
58 *
59 * Linus
60 */
61
62 #define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
63 #define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
64
65 #define DATA_BUFFER_USED(bh) \
66 (atomic_read(&bh->b_count)>1 || buffer_locked(bh))
67
ufs_trunc_direct(struct inode * inode)68 static int ufs_trunc_direct (struct inode * inode)
69 {
70 struct super_block * sb;
71 struct ufs_sb_private_info * uspi;
72 struct buffer_head * bh;
73 u32 * p;
74 unsigned frag1, frag2, frag3, frag4, block1, block2;
75 unsigned frag_to_free, free_count;
76 unsigned i, j, tmp;
77 int retry;
78
79 UFSD(("ENTER\n"))
80
81 sb = inode->i_sb;
82 uspi = sb->u.ufs_sb.s_uspi;
83
84 frag_to_free = 0;
85 free_count = 0;
86 retry = 0;
87
88 frag1 = DIRECT_FRAGMENT;
89 frag4 = min_t(u32, UFS_NDIR_FRAGMENT, inode->u.ufs_i.i_lastfrag);
90 frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
91 frag3 = frag4 & ~uspi->s_fpbmask;
92 block1 = block2 = 0;
93 if (frag2 > frag3) {
94 frag2 = frag4;
95 frag3 = frag4 = 0;
96 }
97 else if (frag2 < frag3) {
98 block1 = ufs_fragstoblks (frag2);
99 block2 = ufs_fragstoblks (frag3);
100 }
101
102 UFSD(("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4))
103
104 if (frag1 >= frag2)
105 goto next1;
106
107 /*
108 * Free first free fragments
109 */
110 p = inode->u.ufs_i.i_u1.i_data + ufs_fragstoblks (frag1);
111 tmp = fs32_to_cpu(sb, *p);
112 if (!tmp )
113 ufs_panic (sb, "ufs_trunc_direct", "internal error");
114 frag1 = ufs_fragnum (frag1);
115 frag2 = ufs_fragnum (frag2);
116 for (j = frag1; j < frag2; j++) {
117 bh = sb_get_hash_table (sb, tmp + j);
118 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
119 retry = 1;
120 brelse (bh);
121 goto next1;
122 }
123 bforget (bh);
124 }
125 inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
126 mark_inode_dirty(inode);
127 ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
128 frag_to_free = tmp + frag1;
129
130 next1:
131 /*
132 * Free whole blocks
133 */
134 for (i = block1 ; i < block2; i++) {
135 p = inode->u.ufs_i.i_u1.i_data + i;
136 tmp = fs32_to_cpu(sb, *p);
137 if (!tmp)
138 continue;
139 for (j = 0; j < uspi->s_fpb; j++) {
140 bh = sb_get_hash_table(sb, tmp + j);
141 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
142 retry = 1;
143 brelse (bh);
144 goto next2;
145 }
146 bforget (bh);
147 }
148 *p = 0;
149 inode->i_blocks -= uspi->s_nspb;
150 mark_inode_dirty(inode);
151 if (free_count == 0) {
152 frag_to_free = tmp;
153 free_count = uspi->s_fpb;
154 } else if (free_count > 0 && frag_to_free == tmp - free_count)
155 free_count += uspi->s_fpb;
156 else {
157 ufs_free_blocks (inode, frag_to_free, free_count);
158 frag_to_free = tmp;
159 free_count = uspi->s_fpb;
160 }
161 next2:;
162 }
163
164 if (free_count > 0)
165 ufs_free_blocks (inode, frag_to_free, free_count);
166
167 if (frag3 >= frag4)
168 goto next3;
169
170 /*
171 * Free last free fragments
172 */
173 p = inode->u.ufs_i.i_u1.i_data + ufs_fragstoblks (frag3);
174 tmp = fs32_to_cpu(sb, *p);
175 if (!tmp )
176 ufs_panic(sb, "ufs_truncate_direct", "internal error");
177 frag4 = ufs_fragnum (frag4);
178 for (j = 0; j < frag4; j++) {
179 bh = sb_get_hash_table (sb, tmp + j);
180 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
181 retry = 1;
182 brelse (bh);
183 goto next1;
184 }
185 bforget (bh);
186 }
187 *p = 0;
188 inode->i_blocks -= frag4 << uspi->s_nspfshift;
189 mark_inode_dirty(inode);
190 ufs_free_fragments (inode, tmp, frag4);
191 next3:
192
193 UFSD(("EXIT\n"))
194 return retry;
195 }
196
197
ufs_trunc_indirect(struct inode * inode,unsigned offset,u32 * p)198 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, u32 * p)
199 {
200 struct super_block * sb;
201 struct ufs_sb_private_info * uspi;
202 struct ufs_buffer_head * ind_ubh;
203 struct buffer_head * bh;
204 u32 * ind;
205 unsigned indirect_block, i, j, tmp;
206 unsigned frag_to_free, free_count;
207 int retry;
208
209 UFSD(("ENTER\n"))
210
211 sb = inode->i_sb;
212 uspi = sb->u.ufs_sb.s_uspi;
213
214 frag_to_free = 0;
215 free_count = 0;
216 retry = 0;
217
218 tmp = fs32_to_cpu(sb, *p);
219 if (!tmp)
220 return 0;
221 ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
222 if (tmp != fs32_to_cpu(sb, *p)) {
223 ubh_brelse (ind_ubh);
224 return 1;
225 }
226 if (!ind_ubh) {
227 *p = 0;
228 return 0;
229 }
230
231 indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
232 for (i = indirect_block; i < uspi->s_apb; i++) {
233 ind = ubh_get_addr32 (ind_ubh, i);
234 tmp = fs32_to_cpu(sb, *ind);
235 if (!tmp)
236 continue;
237 for (j = 0; j < uspi->s_fpb; j++) {
238 bh = sb_get_hash_table(sb, tmp + j);
239 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *ind)) {
240 retry = 1;
241 brelse (bh);
242 goto next;
243 }
244 bforget (bh);
245 }
246 *ind = 0;
247 ubh_mark_buffer_dirty(ind_ubh);
248 if (free_count == 0) {
249 frag_to_free = tmp;
250 free_count = uspi->s_fpb;
251 } else if (free_count > 0 && frag_to_free == tmp - free_count)
252 free_count += uspi->s_fpb;
253 else {
254 ufs_free_blocks (inode, frag_to_free, free_count);
255 frag_to_free = tmp;
256 free_count = uspi->s_fpb;
257 }
258 inode->i_blocks -= uspi->s_nspb;
259 mark_inode_dirty(inode);
260 next:;
261 }
262
263 if (free_count > 0) {
264 ufs_free_blocks (inode, frag_to_free, free_count);
265 }
266 for (i = 0; i < uspi->s_apb; i++)
267 if (*ubh_get_addr32(ind_ubh,i))
268 break;
269 if (i >= uspi->s_apb) {
270 if (ubh_max_bcount(ind_ubh) != 1) {
271 retry = 1;
272 }
273 else {
274 tmp = fs32_to_cpu(sb, *p);
275 *p = 0;
276 inode->i_blocks -= uspi->s_nspb;
277 mark_inode_dirty(inode);
278 ufs_free_blocks (inode, tmp, uspi->s_fpb);
279 ubh_bforget(ind_ubh);
280 ind_ubh = NULL;
281 }
282 }
283 if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
284 ubh_ll_rw_block (WRITE, 1, &ind_ubh);
285 ubh_wait_on_buffer (ind_ubh);
286 }
287 ubh_brelse (ind_ubh);
288
289 UFSD(("EXIT\n"))
290
291 return retry;
292 }
293
ufs_trunc_dindirect(struct inode * inode,unsigned offset,u32 * p)294 static int ufs_trunc_dindirect (struct inode * inode, unsigned offset, u32 * p)
295 {
296 struct super_block * sb;
297 struct ufs_sb_private_info * uspi;
298 struct ufs_buffer_head * dind_bh;
299 unsigned i, tmp, dindirect_block;
300 u32 * dind;
301 int retry = 0;
302
303 UFSD(("ENTER\n"))
304
305 sb = inode->i_sb;
306 uspi = sb->u.ufs_sb.s_uspi;
307
308 dindirect_block = (DIRECT_BLOCK > offset)
309 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
310 retry = 0;
311
312 tmp = fs32_to_cpu(sb, *p);
313 if (!tmp)
314 return 0;
315 dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
316 if (tmp != fs32_to_cpu(sb, *p)) {
317 ubh_brelse (dind_bh);
318 return 1;
319 }
320 if (!dind_bh) {
321 *p = 0;
322 return 0;
323 }
324
325 for (i = dindirect_block ; i < uspi->s_apb ; i++) {
326 dind = ubh_get_addr32 (dind_bh, i);
327 tmp = fs32_to_cpu(sb, *dind);
328 if (!tmp)
329 continue;
330 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
331 ubh_mark_buffer_dirty(dind_bh);
332 }
333
334 for (i = 0; i < uspi->s_apb; i++)
335 if (*ubh_get_addr32 (dind_bh, i))
336 break;
337 if (i >= uspi->s_apb) {
338 if (ubh_max_bcount(dind_bh) != 1)
339 retry = 1;
340 else {
341 tmp = fs32_to_cpu(sb, *p);
342 *p = 0;
343 inode->i_blocks -= uspi->s_nspb;
344 mark_inode_dirty(inode);
345 ufs_free_blocks (inode, tmp, uspi->s_fpb);
346 ubh_bforget(dind_bh);
347 dind_bh = NULL;
348 }
349 }
350 if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
351 ubh_ll_rw_block (WRITE, 1, &dind_bh);
352 ubh_wait_on_buffer (dind_bh);
353 }
354 ubh_brelse (dind_bh);
355
356 UFSD(("EXIT\n"))
357
358 return retry;
359 }
360
ufs_trunc_tindirect(struct inode * inode)361 static int ufs_trunc_tindirect (struct inode * inode)
362 {
363 struct super_block * sb;
364 struct ufs_sb_private_info * uspi;
365 struct ufs_buffer_head * tind_bh;
366 unsigned tindirect_block, tmp, i;
367 u32 * tind, * p;
368 int retry;
369
370 UFSD(("ENTER\n"))
371
372 sb = inode->i_sb;
373 uspi = sb->u.ufs_sb.s_uspi;
374 retry = 0;
375
376 tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
377 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
378 p = inode->u.ufs_i.i_u1.i_data + UFS_TIND_BLOCK;
379 if (!(tmp = fs32_to_cpu(sb, *p)))
380 return 0;
381 tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
382 if (tmp != fs32_to_cpu(sb, *p)) {
383 ubh_brelse (tind_bh);
384 return 1;
385 }
386 if (!tind_bh) {
387 *p = 0;
388 return 0;
389 }
390
391 for (i = tindirect_block ; i < uspi->s_apb ; i++) {
392 tind = ubh_get_addr32 (tind_bh, i);
393 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
394 uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
395 ubh_mark_buffer_dirty(tind_bh);
396 }
397 for (i = 0; i < uspi->s_apb; i++)
398 if (*ubh_get_addr32 (tind_bh, i))
399 break;
400 if (i >= uspi->s_apb) {
401 if (ubh_max_bcount(tind_bh) != 1)
402 retry = 1;
403 else {
404 tmp = fs32_to_cpu(sb, *p);
405 *p = 0;
406 inode->i_blocks -= uspi->s_nspb;
407 mark_inode_dirty(inode);
408 ufs_free_blocks (inode, tmp, uspi->s_fpb);
409 ubh_bforget(tind_bh);
410 tind_bh = NULL;
411 }
412 }
413 if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
414 ubh_ll_rw_block (WRITE, 1, &tind_bh);
415 ubh_wait_on_buffer (tind_bh);
416 }
417 ubh_brelse (tind_bh);
418
419 UFSD(("EXIT\n"))
420 return retry;
421 }
422
ufs_truncate(struct inode * inode)423 void ufs_truncate (struct inode * inode)
424 {
425 struct super_block * sb;
426 struct ufs_sb_private_info * uspi;
427 struct buffer_head * bh;
428 unsigned offset;
429 int err, retry;
430
431 UFSD(("ENTER\n"))
432 sb = inode->i_sb;
433 uspi = sb->u.ufs_sb.s_uspi;
434
435 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
436 return;
437 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
438 return;
439 while (1) {
440 retry = ufs_trunc_direct(inode);
441 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
442 (u32 *) &inode->u.ufs_i.i_u1.i_data[UFS_IND_BLOCK]);
443 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
444 (u32 *) &inode->u.ufs_i.i_u1.i_data[UFS_DIND_BLOCK]);
445 retry |= ufs_trunc_tindirect (inode);
446 if (!retry)
447 break;
448 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
449 ufs_sync_inode (inode);
450 run_task_queue(&tq_disk);
451 yield();
452 }
453 offset = inode->i_size & uspi->s_fshift;
454 if (offset) {
455 bh = ufs_bread (inode, inode->i_size >> uspi->s_fshift, 0, &err);
456 if (bh) {
457 memset (bh->b_data + offset, 0, uspi->s_fsize - offset);
458 mark_buffer_dirty (bh);
459 brelse (bh);
460 }
461 }
462 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
463 inode->u.ufs_i.i_lastfrag = DIRECT_FRAGMENT;
464 mark_inode_dirty(inode);
465 UFSD(("EXIT\n"))
466 }
467