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   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         inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
 116         mark_inode_dirty(inode);
 117         ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
 118         frag_to_free = tmp + frag1;
 119
 120 next1:
 121         /*
 122          * Free whole blocks
 123          */
 124         for (i = block1 ; i < block2; i++) {
 125                 p = ufsi->i_u1.i_data + i;
 126                 tmp = fs32_to_cpu(sb, *p);
 127                 if (!tmp)
 128                         continue;
 129
 130                 *p = 0;
 131                 inode->i_blocks -= uspi->s_nspb;
 132                 mark_inode_dirty(inode);
 133                 if (free_count == 0) {
 134                         frag_to_free = tmp;
 135                         free_count = uspi->s_fpb;
 136                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 137                         free_count += uspi->s_fpb;
 138                 else {
 139                         ufs_free_blocks (inode, frag_to_free, free_count);
 140                         frag_to_free = tmp;
 141                         free_count = uspi->s_fpb;
 142                 }
 143         }
 144
 145         if (free_count > 0)
 146                 ufs_free_blocks (inode, frag_to_free, free_count);
 147
 148         if (frag3 >= frag4)
 149                 goto next3;
 150
 151         /*
 152          * Free last free fragments
 153          */
 154         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
 155         tmp = fs32_to_cpu(sb, *p);
 156         if (!tmp )
 157                 ufs_panic(sb, "ufs_truncate_direct", "internal error");
 158         frag4 = ufs_fragnum (frag4);
 159
 160         *p = 0;
 161         inode->i_blocks -= frag4 << uspi->s_nspfshift;
 162         mark_inode_dirty(inode);
 163         ufs_free_fragments (inode, tmp, frag4);
 164  next3:
 165
 166         UFSD("EXIT\n");
 167         return retry;
 168 }
 169
 170
 171 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
 172 {
 173         struct super_block * sb;
 174         struct ufs_sb_private_info * uspi;
 175         struct ufs_buffer_head * ind_ubh;
 176         __fs32 * ind;
 177         unsigned indirect_block, i, tmp;
 178         unsigned frag_to_free, free_count;
 179         int retry;
 180
 181         UFSD("ENTER\n");
 182
 183         sb = inode->i_sb;
 184         uspi = UFS_SB(sb)->s_uspi;
 185
 186         frag_to_free = 0;
 187         free_count = 0;
 188         retry = 0;
 189
 190         tmp = fs32_to_cpu(sb, *p);
 191         if (!tmp)
 192                 return 0;
 193         ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
 194         if (tmp != fs32_to_cpu(sb, *p)) {
 195                 ubh_brelse (ind_ubh);
 196                 return 1;
 197         }
 198         if (!ind_ubh) {
 199                 *p = 0;
 200                 return 0;
 201         }
 202
 203         indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
 204         for (i = indirect_block; i < uspi->s_apb; i++) {
 205                 ind = ubh_get_addr32 (ind_ubh, i);
 206                 tmp = fs32_to_cpu(sb, *ind);
 207                 if (!tmp)
 208                         continue;
 209
 210                 *ind = 0;
 211                 ubh_mark_buffer_dirty(ind_ubh);
 212                 if (free_count == 0) {
 213                         frag_to_free = tmp;
 214                         free_count = uspi->s_fpb;
 215                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 216                         free_count += uspi->s_fpb;
 217                 else {
 218                         ufs_free_blocks (inode, frag_to_free, free_count);
 219                         frag_to_free = tmp;
 220                         free_count = uspi->s_fpb;
 221                 }
 222                 inode->i_blocks -= uspi->s_nspb;
 223                 mark_inode_dirty(inode);
 224         }
 225
 226         if (free_count > 0) {
 227                 ufs_free_blocks (inode, frag_to_free, free_count);
 228         }
 229         for (i = 0; i < uspi->s_apb; i++)
 230                 if (*ubh_get_addr32(ind_ubh,i))
 231                         break;
 232         if (i >= uspi->s_apb) {
 233                 tmp = fs32_to_cpu(sb, *p);
 234                 *p = 0;
 235                 inode->i_blocks -= uspi->s_nspb;
 236                 mark_inode_dirty(inode);
 237                 ufs_free_blocks (inode, tmp, uspi->s_fpb);
 238                 ubh_bforget(ind_ubh);
 239                 ind_ubh = NULL;
 240         }
 241         if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
 242                 ubh_ll_rw_block (SWRITE, 1, &ind_ubh);
 243                 ubh_wait_on_buffer (ind_ubh);
 244         }
 245         ubh_brelse (ind_ubh);
 246
 247         UFSD("EXIT\n");
 248
 249         return retry;
 250 }
 251
 252 static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
 253 {
 254         struct super_block * sb;
 255         struct ufs_sb_private_info * uspi;
 256         struct ufs_buffer_head * dind_bh;
 257         unsigned i, tmp, dindirect_block;
 258         __fs32 * dind;
 259         int retry = 0;
 260
 261         UFSD("ENTER\n");
 262
 263         sb = inode->i_sb;
 264         uspi = UFS_SB(sb)->s_uspi;
 265
 266         dindirect_block = (DIRECT_BLOCK > offset)
 267                 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
 268         retry = 0;
 269
 270         tmp = fs32_to_cpu(sb, *p);
 271         if (!tmp)
 272                 return 0;
 273         dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
 274         if (tmp != fs32_to_cpu(sb, *p)) {
 275                 ubh_brelse (dind_bh);
 276                 return 1;
 277         }
 278         if (!dind_bh) {
 279                 *p = 0;
 280                 return 0;
 281         }
 282
 283         for (i = dindirect_block ; i < uspi->s_apb ; i++) {
 284                 dind = ubh_get_addr32 (dind_bh, i);
 285                 tmp = fs32_to_cpu(sb, *dind);
 286                 if (!tmp)
 287                         continue;
 288                 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
 289                 ubh_mark_buffer_dirty(dind_bh);
 290         }
 291
 292         for (i = 0; i < uspi->s_apb; i++)
 293                 if (*ubh_get_addr32 (dind_bh, i))
 294                         break;
 295         if (i >= uspi->s_apb) {
 296                 tmp = fs32_to_cpu(sb, *p);
 297                 *p = 0;
 298                 inode->i_blocks -= uspi->s_nspb;
 299                 mark_inode_dirty(inode);
 300                 ufs_free_blocks (inode, tmp, uspi->s_fpb);
 301                 ubh_bforget(dind_bh);
 302                 dind_bh = NULL;
 303         }
 304         if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
 305                 ubh_ll_rw_block (SWRITE, 1, &dind_bh);
 306                 ubh_wait_on_buffer (dind_bh);
 307         }
 308         ubh_brelse (dind_bh);
 309
 310         UFSD("EXIT\n");
 311
 312         return retry;
 313 }
 314
 315 static int ufs_trunc_tindirect (struct inode * inode)
 316 {
 317         struct ufs_inode_info *ufsi = UFS_I(inode);
 318         struct super_block * sb;
 319         struct ufs_sb_private_info * uspi;
 320         struct ufs_buffer_head * tind_bh;
 321         unsigned tindirect_block, tmp, i;
 322         __fs32 * tind, * p;
 323         int retry;
 324
 325         UFSD("ENTER\n");
 326
 327         sb = inode->i_sb;
 328         uspi = UFS_SB(sb)->s_uspi;
 329         retry = 0;
 330
 331         tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
 332                 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
 333         p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
 334         if (!(tmp = fs32_to_cpu(sb, *p)))
 335                 return 0;
 336         tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
 337         if (tmp != fs32_to_cpu(sb, *p)) {
 338                 ubh_brelse (tind_bh);
 339                 return 1;
 340         }
 341         if (!tind_bh) {
 342                 *p = 0;
 343                 return 0;
 344         }
 345
 346         for (i = tindirect_block ; i < uspi->s_apb ; i++) {
 347                 tind = ubh_get_addr32 (tind_bh, i);
 348                 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
 349                         uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
 350                 ubh_mark_buffer_dirty(tind_bh);
 351         }
 352         for (i = 0; i < uspi->s_apb; i++)
 353                 if (*ubh_get_addr32 (tind_bh, i))
 354                         break;
 355         if (i >= uspi->s_apb) {
 356                 tmp = fs32_to_cpu(sb, *p);
 357                 *p = 0;
 358                 inode->i_blocks -= uspi->s_nspb;
 359                 mark_inode_dirty(inode);
 360                 ufs_free_blocks (inode, tmp, uspi->s_fpb);
 361                 ubh_bforget(tind_bh);
 362                 tind_bh = NULL;
 363         }
 364         if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
 365                 ubh_ll_rw_block (SWRITE, 1, &tind_bh);
 366                 ubh_wait_on_buffer (tind_bh);
 367         }
 368         ubh_brelse (tind_bh);
 369
 370         UFSD("EXIT\n");
 371         return retry;
 372 }
 373
 374 void ufs_truncate (struct inode * inode)
 375 {
 376         struct ufs_inode_info *ufsi = UFS_I(inode);
 377         struct super_block * sb;
 378         struct ufs_sb_private_info * uspi;
 379         int retry;
 380
 381         UFSD("ENTER\n");
 382         sb = inode->i_sb;
 383         uspi = UFS_SB(sb)->s_uspi;
 384
 385         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 386                 return;
 387         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 388                 return;
 389
 390         block_truncate_page(inode->i_mapping,   inode->i_size, ufs_getfrag_block);
 391
 392         lock_kernel();
 393         while (1) {
 394                 retry = ufs_trunc_direct(inode);
 395                 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
 396                         (__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
 397                 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
 398                         (__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
 399                 retry |= ufs_trunc_tindirect (inode);
 400                 if (!retry)
 401                         break;
 402                 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
 403                         ufs_sync_inode (inode);
 404                 blk_run_address_space(inode->i_mapping);
 405                 yield();
 406         }
 407
 408         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 409         ufsi->i_lastfrag = DIRECT_FRAGMENT;
 410         unlock_kernel();
 411         mark_inode_dirty(inode);
 412         UFSD("EXIT\n");
 413 }