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 #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
  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         unsigned swab;
  79
  80         UFSD(("ENTER\n"))
  81
  82         sb = inode->i_sb;
  83         swab = sb->u.ufs_sb.s_swab;
  84         uspi = sb->u.ufs_sb.s_uspi;
  85
  86         frag_to_free = 0;
  87         free_count = 0;
  88         retry = 0;
  89
  90         frag1 = DIRECT_FRAGMENT;
  91         frag4 = min (UFS_NDIR_FRAGMENT, inode->u.ufs_i.i_lastfrag);
  92         frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
  93         frag3 = frag4 & ~uspi->s_fpbmask;
  94         block1 = block2 = 0;
  95         if (frag2 > frag3) {
  96                 frag2 = frag4;
  97                 frag3 = frag4 = 0;
  98         }
  99         else if (frag2 < frag3) {
 100                 block1 = ufs_fragstoblks (frag2);
 101                 block2 = ufs_fragstoblks (frag3);
 102         }
 103
 104         UFSD(("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4))
 105
 106         if (frag1 >= frag2)
 107                 goto next1;
 108
 109         /*
 110          * Free first free fragments
 111          */
 112         p = inode->u.ufs_i.i_u1.i_data + ufs_fragstoblks (frag1);
 113         tmp = SWAB32(*p);
 114         if (!tmp )
 115                 ufs_panic (sb, "ufs_trunc_direct", "internal error");
 116         frag1 = ufs_fragnum (frag1);
 117         frag2 = ufs_fragnum (frag2);
 118         for (j = frag1; j < frag2; j++) {
 119                 bh = get_hash_table (sb->s_dev, tmp + j, uspi->s_fsize);
 120                 if ((bh && DATA_BUFFER_USED(bh)) || tmp != SWAB32(*p)) {
 121                         retry = 1;
 122                         brelse (bh);
 123                         goto next1;
 124                 }
 125                 bforget (bh);
 126         }
 127         inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
 128         mark_inode_dirty(inode);
 129         ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
 130         frag_to_free = tmp + frag1;
 131
 132 next1:
 133         /*
 134          * Free whole blocks
 135          */
 136         for (i = block1 ; i < block2; i++) {
 137                 p = inode->u.ufs_i.i_u1.i_data + i;
 138                 tmp = SWAB32(*p);
 139                 if (!tmp)
 140                         continue;
 141                 for (j = 0; j < uspi->s_fpb; j++) {
 142                         bh = get_hash_table (sb->s_dev, tmp + j, uspi->s_fsize);
 143                         if ((bh && DATA_BUFFER_USED(bh)) || tmp != SWAB32(*p)) {
 144                                 retry = 1;
 145                                 brelse (bh);
 146                                 goto next2;
 147                         }
 148                         bforget (bh);
 149                 }
 150                 *p = SWAB32(0);
 151                 inode->i_blocks -= uspi->s_nspb;
 152                 mark_inode_dirty(inode);
 153                 if (free_count == 0) {
 154                         frag_to_free = tmp;
 155                         free_count = uspi->s_fpb;
 156                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 157                         free_count += uspi->s_fpb;
 158                 else {
 159                         ufs_free_blocks (inode, frag_to_free, free_count);
 160                         frag_to_free = tmp;
 161                         free_count = uspi->s_fpb;
 162                 }
 163 next2:
 164         }
 165
 166         if (free_count > 0)
 167                 ufs_free_blocks (inode, frag_to_free, free_count);
 168
 169         if (frag3 >= frag4)
 170                 goto next3;
 171
 172         /*
 173          * Free last free fragments
 174          */
 175         p = inode->u.ufs_i.i_u1.i_data + ufs_fragstoblks (frag3);
 176         tmp = SWAB32(*p);
 177         if (!tmp )
 178                 ufs_panic(sb, "ufs_truncate_direct", "internal error");
 179         frag4 = ufs_fragnum (frag4);
 180         for (j = 0; j < frag4; j++) {
 181                 bh = get_hash_table (sb->s_dev, tmp + j, uspi->s_fsize);
 182                 if ((bh && DATA_BUFFER_USED(bh)) || tmp != SWAB32(*p)) {
 183                         retry = 1;
 184                         brelse (bh);
 185                         goto next1;
 186                 }
 187                 bforget (bh);
 188         }
 189         *p = SWAB32(0);
 190         inode->i_blocks -= frag4 << uspi->s_nspfshift;
 191         mark_inode_dirty(inode);
 192         ufs_free_fragments (inode, tmp, frag4);
 193  next3:
 194
 195         UFSD(("EXIT\n"))
 196         return retry;
 197 }
 198
 199
 200 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, u32 * p)
 201 {
 202         struct super_block * sb;
 203         struct ufs_sb_private_info * uspi;
 204         struct ufs_buffer_head * ind_ubh;
 205         struct buffer_head * bh;
 206         u32 * ind;
 207         unsigned indirect_block, i, j, tmp;
 208         unsigned frag_to_free, free_count;
 209         int retry;
 210         unsigned swab;
 211
 212         UFSD(("ENTER\n"))
 213
 214         sb = inode->i_sb;
 215         swab = sb->u.ufs_sb.s_swab;
 216         uspi = sb->u.ufs_sb.s_uspi;
 217
 218         frag_to_free = 0;
 219         free_count = 0;
 220         retry = 0;
 221
 222         tmp = SWAB32(*p);
 223         if (!tmp)
 224                 return 0;
 225         ind_ubh = ubh_bread (sb->s_dev, tmp, uspi->s_bsize);
 226         if (tmp != SWAB32(*p)) {
 227                 ubh_brelse (ind_ubh);
 228                 return 1;
 229         }
 230         if (!ind_ubh) {
 231                 *p = SWAB32(0);
 232                 return 0;
 233         }
 234
 235         indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
 236         for (i = indirect_block; i < uspi->s_apb; i++) {
 237                 ind = ubh_get_addr32 (ind_ubh, i);
 238                 tmp = SWAB32(*ind);
 239                 if (!tmp)
 240                         continue;
 241                 for (j = 0; j < uspi->s_fpb; j++) {
 242                         bh = get_hash_table (sb->s_dev, tmp + j, uspi->s_fsize);
 243                         if ((bh && DATA_BUFFER_USED(bh)) || tmp != SWAB32(*ind)) {
 244                                 retry = 1;
 245                                 brelse (bh);
 246                                 goto next;
 247                         }
 248                         bforget (bh);
 249                 }
 250                 *ind = SWAB32(0);
 251                 ubh_mark_buffer_dirty(ind_ubh);
 252                 if (free_count == 0) {
 253                         frag_to_free = tmp;
 254                         free_count = uspi->s_fpb;
 255                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 256                         free_count += uspi->s_fpb;
 257                 else {
 258                         ufs_free_blocks (inode, frag_to_free, free_count);
 259                         frag_to_free = tmp;
 260                         free_count = uspi->s_fpb;
 261                 }
 262                 inode->i_blocks -= uspi->s_nspb;
 263                 mark_inode_dirty(inode);
 264 next:
 265         }
 266
 267         if (free_count > 0) {
 268                 ufs_free_blocks (inode, frag_to_free, free_count);
 269         }
 270         for (i = 0; i < uspi->s_apb; i++)
 271                 if (SWAB32(*ubh_get_addr32(ind_ubh,i)))
 272                         break;
 273         if (i >= uspi->s_apb) {
 274                 if (ubh_max_bcount(ind_ubh) != 1) {
 275                         retry = 1;
 276                 }
 277                 else {
 278                         tmp = SWAB32(*p);
 279                         *p = SWAB32(0);
 280                         inode->i_blocks -= uspi->s_nspb;
 281                         mark_inode_dirty(inode);
 282                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 283                         ubh_bforget(ind_ubh);
 284                         ind_ubh = NULL;
 285                 }
 286         }
 287         if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
 288                 ubh_ll_rw_block (WRITE, 1, &ind_ubh);
 289                 ubh_wait_on_buffer (ind_ubh);
 290         }
 291         ubh_brelse (ind_ubh);
 292
 293         UFSD(("EXIT\n"))
 294
 295         return retry;
 296 }
 297
 298 static int ufs_trunc_dindirect (struct inode * inode, unsigned offset, u32 * p)
 299 {
 300         struct super_block * sb;
 301         struct ufs_sb_private_info * uspi;
 302         struct ufs_buffer_head * dind_bh;
 303         unsigned i, tmp, dindirect_block;
 304         u32 * dind;
 305         int retry = 0;
 306         unsigned swab;
 307
 308         UFSD(("ENTER\n"))
 309
 310         sb = inode->i_sb;
 311         swab = sb->u.ufs_sb.s_swab;
 312         uspi = sb->u.ufs_sb.s_uspi;
 313
 314         dindirect_block = (DIRECT_BLOCK > offset)
 315                 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
 316         retry = 0;
 317
 318         tmp = SWAB32(*p);
 319         if (!tmp)
 320                 return 0;
 321         dind_bh = ubh_bread (inode->i_dev, tmp, uspi->s_bsize);
 322         if (tmp != SWAB32(*p)) {
 323                 ubh_brelse (dind_bh);
 324                 return 1;
 325         }
 326         if (!dind_bh) {
 327                 *p = SWAB32(0);
 328                 return 0;
 329         }
 330
 331         for (i = dindirect_block ; i < uspi->s_apb ; i++) {
 332                 dind = ubh_get_addr32 (dind_bh, i);
 333                 tmp = SWAB32(*dind);
 334                 if (!tmp)
 335                         continue;
 336                 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
 337                 ubh_mark_buffer_dirty(dind_bh);
 338         }
 339
 340         for (i = 0; i < uspi->s_apb; i++)
 341                 if (SWAB32(*ubh_get_addr32 (dind_bh, i)))
 342                         break;
 343         if (i >= uspi->s_apb) {
 344                 if (ubh_max_bcount(dind_bh) != 1)
 345                         retry = 1;
 346                 else {
 347                         tmp = SWAB32(*p);
 348                         *p = SWAB32(0);
 349                         inode->i_blocks -= uspi->s_nspb;
 350                         mark_inode_dirty(inode);
 351                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 352                         ubh_bforget(dind_bh);
 353                         dind_bh = NULL;
 354                 }
 355         }
 356         if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
 357                 ubh_ll_rw_block (WRITE, 1, &dind_bh);
 358                 ubh_wait_on_buffer (dind_bh);
 359         }
 360         ubh_brelse (dind_bh);
 361
 362         UFSD(("EXIT\n"))
 363
 364         return retry;
 365 }
 366
 367 static int ufs_trunc_tindirect (struct inode * inode)
 368 {
 369         struct super_block * sb;
 370         struct ufs_sb_private_info * uspi;
 371         struct ufs_buffer_head * tind_bh;
 372         unsigned tindirect_block, tmp, i;
 373         u32 * tind, * p;
 374         int retry;
 375         unsigned swab;
 376
 377         UFSD(("ENTER\n"))
 378
 379         sb = inode->i_sb;
 380         swab = sb->u.ufs_sb.s_swab;
 381         uspi = sb->u.ufs_sb.s_uspi;
 382         retry = 0;
 383
 384         tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
 385                 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
 386         p = inode->u.ufs_i.i_u1.i_data + UFS_TIND_BLOCK;
 387         if (!(tmp = SWAB32(*p)))
 388                 return 0;
 389         tind_bh = ubh_bread (sb->s_dev, tmp, uspi->s_bsize);
 390         if (tmp != SWAB32(*p)) {
 391                 ubh_brelse (tind_bh);
 392                 return 1;
 393         }
 394         if (!tind_bh) {
 395                 *p = SWAB32(0);
 396                 return 0;
 397         }
 398
 399         for (i = tindirect_block ; i < uspi->s_apb ; i++) {
 400                 tind = ubh_get_addr32 (tind_bh, i);
 401                 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
 402                         uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
 403                 ubh_mark_buffer_dirty(tind_bh);
 404         }
 405         for (i = 0; i < uspi->s_apb; i++)
 406                 if (SWAB32(*ubh_get_addr32 (tind_bh, i)))
 407                         break;
 408         if (i >= uspi->s_apb) {
 409                 if (ubh_max_bcount(tind_bh) != 1)
 410                         retry = 1;
 411                 else {
 412                         tmp = SWAB32(*p);
 413                         *p = SWAB32(0);
 414                         inode->i_blocks -= uspi->s_nspb;
 415                         mark_inode_dirty(inode);
 416                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 417                         ubh_bforget(tind_bh);
 418                         tind_bh = NULL;
 419                 }
 420         }
 421         if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
 422                 ubh_ll_rw_block (WRITE, 1, &tind_bh);
 423                 ubh_wait_on_buffer (tind_bh);
 424         }
 425         ubh_brelse (tind_bh);
 426
 427         UFSD(("EXIT\n"))
 428         return retry;
 429 }
 430
 431 void ufs_truncate (struct inode * inode)
 432 {
 433         struct super_block * sb;
 434         struct ufs_sb_private_info * uspi;
 435         struct buffer_head * bh;
 436         unsigned offset;
 437         int err, retry;
 438
 439         UFSD(("ENTER\n"))
 440         sb = inode->i_sb;
 441         uspi = sb->u.ufs_sb.s_uspi;
 442
 443         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 444                 return;
 445         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 446                 return;
 447         while (1) {
 448                 retry = ufs_trunc_direct(inode);
 449                 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
 450                         (u32 *) &inode->u.ufs_i.i_u1.i_data[UFS_IND_BLOCK]);
 451                 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
 452                         (u32 *) &inode->u.ufs_i.i_u1.i_data[UFS_DIND_BLOCK]);
 453                 retry |= ufs_trunc_tindirect (inode);
 454                 if (!retry)
 455                         break;
 456                 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
 457                         ufs_sync_inode (inode);
 458                 run_task_queue(&tq_disk);
 459                 current->policy |= SCHED_YIELD;
 460                 schedule ();
 461
 462
 463         }
 464         offset = inode->i_size & uspi->s_fshift;
 465         if (offset) {
 466                 bh = ufs_bread (inode, inode->i_size >> uspi->s_fshift, 0, &err);
 467                 if (bh) {
 468                         memset (bh->b_data + offset, 0, uspi->s_fsize - offset);
 469                         mark_buffer_dirty (bh);
 470                         brelse (bh);
 471                 }
 472         }
 473         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 474         inode->u.ufs_i.i_lastfrag = DIRECT_FRAGMENT;
 475         mark_inode_dirty(inode);
 476         UFSD(("EXIT\n"))
 477 }