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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         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, 1, &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, 1, &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, 1, &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 }