3c3b301f87014eeec6327e7480befd367d8ac336
[linux-2.6.git] / fs / ufs / truncate.c
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 /*
33  * Modified to avoid infinite loop on 2006 by
34  * Evgeniy Dushistov <dushistov@mail.ru>
35  */
36
37 #include <linux/errno.h>
38 #include <linux/fs.h>
39 #include <linux/ufs_fs.h>
40 #include <linux/fcntl.h>
41 #include <linux/time.h>
42 #include <linux/stat.h>
43 #include <linux/string.h>
44 #include <linux/smp_lock.h>
45 #include <linux/buffer_head.h>
46 #include <linux/blkdev.h>
47 #include <linux/sched.h>
48
49 #include "swab.h"
50 #include "util.h"
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
66 static int ufs_trunc_direct (struct inode * inode)
67 {
68         struct ufs_inode_info *ufsi = UFS_I(inode);
69         struct super_block * sb;
70         struct ufs_sb_private_info * uspi;
71         __fs32 * p;
72         unsigned frag1, frag2, frag3, frag4, block1, block2;
73         unsigned frag_to_free, free_count;
74         unsigned i, tmp;
75         int retry;
76         
77         UFSD("ENTER\n");
78
79         sb = inode->i_sb;
80         uspi = UFS_SB(sb)->s_uspi;
81         
82         frag_to_free = 0;
83         free_count = 0;
84         retry = 0;
85         
86         frag1 = DIRECT_FRAGMENT;
87         frag4 = min_t(u32, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
88         frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
89         frag3 = frag4 & ~uspi->s_fpbmask;
90         block1 = block2 = 0;
91         if (frag2 > frag3) {
92                 frag2 = frag4;
93                 frag3 = frag4 = 0;
94         }
95         else if (frag2 < frag3) {
96                 block1 = ufs_fragstoblks (frag2);
97                 block2 = ufs_fragstoblks (frag3);
98         }
99
100         UFSD("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4);
101
102         if (frag1 >= frag2)
103                 goto next1;             
104
105         /*
106          * Free first free fragments
107          */
108         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag1);
109         tmp = fs32_to_cpu(sb, *p);
110         if (!tmp )
111                 ufs_panic (sb, "ufs_trunc_direct", "internal error");
112         frag1 = ufs_fragnum (frag1);
113         frag2 = ufs_fragnum (frag2);
114
115         ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
116         mark_inode_dirty(inode);
117         frag_to_free = tmp + frag1;
118
119 next1:
120         /*
121          * Free whole blocks
122          */
123         for (i = block1 ; i < block2; i++) {
124                 p = ufsi->i_u1.i_data + i;
125                 tmp = fs32_to_cpu(sb, *p);
126                 if (!tmp)
127                         continue;
128
129                 *p = 0;
130
131                 if (free_count == 0) {
132                         frag_to_free = tmp;
133                         free_count = uspi->s_fpb;
134                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
135                         free_count += uspi->s_fpb;
136                 else {
137                         ufs_free_blocks (inode, frag_to_free, free_count);
138                         frag_to_free = tmp;
139                         free_count = uspi->s_fpb;
140                 }
141                 mark_inode_dirty(inode);
142         }
143         
144         if (free_count > 0)
145                 ufs_free_blocks (inode, frag_to_free, free_count);
146
147         if (frag3 >= frag4)
148                 goto next3;
149
150         /*
151          * Free last free fragments
152          */
153         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
154         tmp = fs32_to_cpu(sb, *p);
155         if (!tmp )
156                 ufs_panic(sb, "ufs_truncate_direct", "internal error");
157         frag4 = ufs_fragnum (frag4);
158
159         *p = 0;
160
161         ufs_free_fragments (inode, tmp, frag4);
162         mark_inode_dirty(inode);
163  next3:
164
165         UFSD("EXIT\n");
166         return retry;
167 }
168
169
170 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
171 {
172         struct super_block * sb;
173         struct ufs_sb_private_info * uspi;
174         struct ufs_buffer_head * ind_ubh;
175         __fs32 * ind;
176         unsigned indirect_block, i, tmp;
177         unsigned frag_to_free, free_count;
178         int retry;
179
180         UFSD("ENTER\n");
181                 
182         sb = inode->i_sb;
183         uspi = UFS_SB(sb)->s_uspi;
184
185         frag_to_free = 0;
186         free_count = 0;
187         retry = 0;
188         
189         tmp = fs32_to_cpu(sb, *p);
190         if (!tmp)
191                 return 0;
192         ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
193         if (tmp != fs32_to_cpu(sb, *p)) {
194                 ubh_brelse (ind_ubh);
195                 return 1;
196         }
197         if (!ind_ubh) {
198                 *p = 0;
199                 return 0;
200         }
201
202         indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
203         for (i = indirect_block; i < uspi->s_apb; i++) {
204                 ind = ubh_get_addr32 (ind_ubh, i);
205                 tmp = fs32_to_cpu(sb, *ind);
206                 if (!tmp)
207                         continue;
208
209                 *ind = 0;
210                 ubh_mark_buffer_dirty(ind_ubh);
211                 if (free_count == 0) {
212                         frag_to_free = tmp;
213                         free_count = uspi->s_fpb;
214                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
215                         free_count += uspi->s_fpb;
216                 else {
217                         ufs_free_blocks (inode, frag_to_free, free_count);
218                         frag_to_free = tmp;
219                         free_count = uspi->s_fpb;
220                 }
221
222                 mark_inode_dirty(inode);
223         }
224
225         if (free_count > 0) {
226                 ufs_free_blocks (inode, frag_to_free, free_count);
227         }
228         for (i = 0; i < uspi->s_apb; i++)
229                 if (*ubh_get_addr32(ind_ubh,i))
230                         break;
231         if (i >= uspi->s_apb) {
232                 tmp = fs32_to_cpu(sb, *p);
233                 *p = 0;
234
235                 ufs_free_blocks (inode, tmp, uspi->s_fpb);
236                 mark_inode_dirty(inode);
237                 ubh_bforget(ind_ubh);
238                 ind_ubh = NULL;
239         }
240         if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
241                 ubh_ll_rw_block(SWRITE, ind_ubh);
242                 ubh_wait_on_buffer (ind_ubh);
243         }
244         ubh_brelse (ind_ubh);
245         
246         UFSD("EXIT\n");
247         
248         return retry;
249 }
250
251 static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
252 {
253         struct super_block * sb;
254         struct ufs_sb_private_info * uspi;
255         struct ufs_buffer_head * dind_bh;
256         unsigned i, tmp, dindirect_block;
257         __fs32 * dind;
258         int retry = 0;
259         
260         UFSD("ENTER\n");
261         
262         sb = inode->i_sb;
263         uspi = UFS_SB(sb)->s_uspi;
264
265         dindirect_block = (DIRECT_BLOCK > offset) 
266                 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
267         retry = 0;
268         
269         tmp = fs32_to_cpu(sb, *p);
270         if (!tmp)
271                 return 0;
272         dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
273         if (tmp != fs32_to_cpu(sb, *p)) {
274                 ubh_brelse (dind_bh);
275                 return 1;
276         }
277         if (!dind_bh) {
278                 *p = 0;
279                 return 0;
280         }
281
282         for (i = dindirect_block ; i < uspi->s_apb ; i++) {
283                 dind = ubh_get_addr32 (dind_bh, i);
284                 tmp = fs32_to_cpu(sb, *dind);
285                 if (!tmp)
286                         continue;
287                 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
288                 ubh_mark_buffer_dirty(dind_bh);
289         }
290
291         for (i = 0; i < uspi->s_apb; i++)
292                 if (*ubh_get_addr32 (dind_bh, i))
293                         break;
294         if (i >= uspi->s_apb) {
295                 tmp = fs32_to_cpu(sb, *p);
296                 *p = 0;
297
298                 ufs_free_blocks(inode, tmp, uspi->s_fpb);
299                 mark_inode_dirty(inode);
300                 ubh_bforget(dind_bh);
301                 dind_bh = NULL;
302         }
303         if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
304                 ubh_ll_rw_block(SWRITE, dind_bh);
305                 ubh_wait_on_buffer (dind_bh);
306         }
307         ubh_brelse (dind_bh);
308         
309         UFSD("EXIT\n");
310         
311         return retry;
312 }
313
314 static int ufs_trunc_tindirect (struct inode * inode)
315 {
316         struct ufs_inode_info *ufsi = UFS_I(inode);
317         struct super_block * sb;
318         struct ufs_sb_private_info * uspi;
319         struct ufs_buffer_head * tind_bh;
320         unsigned tindirect_block, tmp, i;
321         __fs32 * tind, * p;
322         int retry;
323         
324         UFSD("ENTER\n");
325
326         sb = inode->i_sb;
327         uspi = UFS_SB(sb)->s_uspi;
328         retry = 0;
329         
330         tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
331                 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
332         p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
333         if (!(tmp = fs32_to_cpu(sb, *p)))
334                 return 0;
335         tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
336         if (tmp != fs32_to_cpu(sb, *p)) {
337                 ubh_brelse (tind_bh);
338                 return 1;
339         }
340         if (!tind_bh) {
341                 *p = 0;
342                 return 0;
343         }
344
345         for (i = tindirect_block ; i < uspi->s_apb ; i++) {
346                 tind = ubh_get_addr32 (tind_bh, i);
347                 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR + 
348                         uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
349                 ubh_mark_buffer_dirty(tind_bh);
350         }
351         for (i = 0; i < uspi->s_apb; i++)
352                 if (*ubh_get_addr32 (tind_bh, i))
353                         break;
354         if (i >= uspi->s_apb) {
355                 tmp = fs32_to_cpu(sb, *p);
356                 *p = 0;
357
358                 ufs_free_blocks(inode, tmp, uspi->s_fpb);
359                 mark_inode_dirty(inode);
360                 ubh_bforget(tind_bh);
361                 tind_bh = NULL;
362         }
363         if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
364                 ubh_ll_rw_block(SWRITE, tind_bh);
365                 ubh_wait_on_buffer (tind_bh);
366         }
367         ubh_brelse (tind_bh);
368         
369         UFSD("EXIT\n");
370         return retry;
371 }
372                 
373 void ufs_truncate (struct inode * inode)
374 {
375         struct ufs_inode_info *ufsi = UFS_I(inode);
376         struct super_block * sb;
377         struct ufs_sb_private_info * uspi;
378         int retry;
379         
380         UFSD("ENTER\n");
381         sb = inode->i_sb;
382         uspi = UFS_SB(sb)->s_uspi;
383
384         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
385                 return;
386         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
387                 return;
388
389         block_truncate_page(inode->i_mapping,   inode->i_size, ufs_getfrag_block);
390
391         lock_kernel();
392         while (1) {
393                 retry = ufs_trunc_direct(inode);
394                 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
395                         (__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
396                 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
397                         (__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
398                 retry |= ufs_trunc_tindirect (inode);
399                 if (!retry)
400                         break;
401                 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
402                         ufs_sync_inode (inode);
403                 blk_run_address_space(inode->i_mapping);
404                 yield();
405         }
406
407         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
408         ufsi->i_lastfrag = DIRECT_FRAGMENT;
409         unlock_kernel();
410         mark_inode_dirty(inode);
411         UFSD("EXIT\n");
412 }