git.oblomov.eu Git - linux-2.6/blob - 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 #undef UFS_TRUNCATE_DEBUG
  53
  54 #ifdef UFS_TRUNCATE_DEBUG
  55 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
  56 #else
  57 #define UFSD(x)
  58 #endif
  59
  60 /*
  61  * Secure deletion currently doesn't work. It interacts very badly
  62  * with buffers shared with memory mappings, and for that reason
  63  * can't be done in the truncate() routines. It should instead be
  64  * done separately in "release()" before calling the truncate routines
  65  * that will release the actual file blocks.
  66  *
  67  *              Linus
  68  */
  69
  70 #define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
  71 #define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
  72
  73
  74 static int ufs_trunc_direct (struct inode * inode)
  75 {
  76         struct ufs_inode_info *ufsi = UFS_I(inode);
  77         struct super_block * sb;
  78         struct ufs_sb_private_info * uspi;
  79         __fs32 * p;
  80         unsigned frag1, frag2, frag3, frag4, block1, block2;
  81         unsigned frag_to_free, free_count;
  82         unsigned i, tmp;
  83         int retry;
  84
  85         UFSD(("ENTER\n"))
  86
  87         sb = inode->i_sb;
  88         uspi = UFS_SB(sb)->s_uspi;
  89
  90         frag_to_free = 0;
  91         free_count = 0;
  92         retry = 0;
  93
  94         frag1 = DIRECT_FRAGMENT;
  95         frag4 = min_t(u32, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
  96         frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
  97         frag3 = frag4 & ~uspi->s_fpbmask;
  98         block1 = block2 = 0;
  99         if (frag2 > frag3) {
 100                 frag2 = frag4;
 101                 frag3 = frag4 = 0;
 102         }
 103         else if (frag2 < frag3) {
 104                 block1 = ufs_fragstoblks (frag2);
 105                 block2 = ufs_fragstoblks (frag3);
 106         }
 107
 108         UFSD(("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4))
 109
 110         if (frag1 >= frag2)
 111                 goto next1;
 112
 113         /*
 114          * Free first free fragments
 115          */
 116         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag1);
 117         tmp = fs32_to_cpu(sb, *p);
 118         if (!tmp )
 119                 ufs_panic (sb, "ufs_trunc_direct", "internal error");
 120         frag1 = ufs_fragnum (frag1);
 121         frag2 = ufs_fragnum (frag2);
 122
 123         inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
 124         mark_inode_dirty(inode);
 125         ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
 126         frag_to_free = tmp + frag1;
 127
 128 next1:
 129         /*
 130          * Free whole blocks
 131          */
 132         for (i = block1 ; i < block2; i++) {
 133                 p = ufsi->i_u1.i_data + i;
 134                 tmp = fs32_to_cpu(sb, *p);
 135                 if (!tmp)
 136                         continue;
 137
 138                 *p = 0;
 139                 inode->i_blocks -= uspi->s_nspb;
 140                 mark_inode_dirty(inode);
 141                 if (free_count == 0) {
 142                         frag_to_free = tmp;
 143                         free_count = uspi->s_fpb;
 144                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 145                         free_count += uspi->s_fpb;
 146                 else {
 147                         ufs_free_blocks (inode, frag_to_free, free_count);
 148                         frag_to_free = tmp;
 149                         free_count = uspi->s_fpb;
 150                 }
 151         }
 152
 153         if (free_count > 0)
 154                 ufs_free_blocks (inode, frag_to_free, free_count);
 155
 156         if (frag3 >= frag4)
 157                 goto next3;
 158
 159         /*
 160          * Free last free fragments
 161          */
 162         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
 163         tmp = fs32_to_cpu(sb, *p);
 164         if (!tmp )
 165                 ufs_panic(sb, "ufs_truncate_direct", "internal error");
 166         frag4 = ufs_fragnum (frag4);
 167
 168         *p = 0;
 169         inode->i_blocks -= frag4 << uspi->s_nspfshift;
 170         mark_inode_dirty(inode);
 171         ufs_free_fragments (inode, tmp, frag4);
 172  next3:
 173
 174         UFSD(("EXIT\n"))
 175         return retry;
 176 }
 177
 178
 179 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
 180 {
 181         struct super_block * sb;
 182         struct ufs_sb_private_info * uspi;
 183         struct ufs_buffer_head * ind_ubh;
 184         __fs32 * ind;
 185         unsigned indirect_block, i, tmp;
 186         unsigned frag_to_free, free_count;
 187         int retry;
 188
 189         UFSD(("ENTER\n"))
 190
 191         sb = inode->i_sb;
 192         uspi = UFS_SB(sb)->s_uspi;
 193
 194         frag_to_free = 0;
 195         free_count = 0;
 196         retry = 0;
 197
 198         tmp = fs32_to_cpu(sb, *p);
 199         if (!tmp)
 200                 return 0;
 201         ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
 202         if (tmp != fs32_to_cpu(sb, *p)) {
 203                 ubh_brelse (ind_ubh);
 204                 return 1;
 205         }
 206         if (!ind_ubh) {
 207                 *p = 0;
 208                 return 0;
 209         }
 210
 211         indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
 212         for (i = indirect_block; i < uspi->s_apb; i++) {
 213                 ind = ubh_get_addr32 (ind_ubh, i);
 214                 tmp = fs32_to_cpu(sb, *ind);
 215                 if (!tmp)
 216                         continue;
 217
 218                 *ind = 0;
 219                 ubh_mark_buffer_dirty(ind_ubh);
 220                 if (free_count == 0) {
 221                         frag_to_free = tmp;
 222                         free_count = uspi->s_fpb;
 223                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 224                         free_count += uspi->s_fpb;
 225                 else {
 226                         ufs_free_blocks (inode, frag_to_free, free_count);
 227                         frag_to_free = tmp;
 228                         free_count = uspi->s_fpb;
 229                 }
 230                 inode->i_blocks -= uspi->s_nspb;
 231                 mark_inode_dirty(inode);
 232         }
 233
 234         if (free_count > 0) {
 235                 ufs_free_blocks (inode, frag_to_free, free_count);
 236         }
 237         for (i = 0; i < uspi->s_apb; i++)
 238                 if (*ubh_get_addr32(ind_ubh,i))
 239                         break;
 240         if (i >= uspi->s_apb) {
 241                 if (ubh_max_bcount(ind_ubh) != 1) {
 242                         retry = 1;
 243                 }
 244                 else {
 245                         tmp = fs32_to_cpu(sb, *p);
 246                         *p = 0;
 247                         inode->i_blocks -= uspi->s_nspb;
 248                         mark_inode_dirty(inode);
 249                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 250                         ubh_bforget(ind_ubh);
 251                         ind_ubh = NULL;
 252                 }
 253         }
 254         if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
 255                 ubh_ll_rw_block (SWRITE, 1, &ind_ubh);
 256                 ubh_wait_on_buffer (ind_ubh);
 257         }
 258         ubh_brelse (ind_ubh);
 259
 260         UFSD(("EXIT\n"))
 261
 262         return retry;
 263 }
 264
 265 static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
 266 {
 267         struct super_block * sb;
 268         struct ufs_sb_private_info * uspi;
 269         struct ufs_buffer_head * dind_bh;
 270         unsigned i, tmp, dindirect_block;
 271         __fs32 * dind;
 272         int retry = 0;
 273
 274         UFSD(("ENTER\n"))
 275
 276         sb = inode->i_sb;
 277         uspi = UFS_SB(sb)->s_uspi;
 278
 279         dindirect_block = (DIRECT_BLOCK > offset)
 280                 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
 281         retry = 0;
 282
 283         tmp = fs32_to_cpu(sb, *p);
 284         if (!tmp)
 285                 return 0;
 286         dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
 287         if (tmp != fs32_to_cpu(sb, *p)) {
 288                 ubh_brelse (dind_bh);
 289                 return 1;
 290         }
 291         if (!dind_bh) {
 292                 *p = 0;
 293                 return 0;
 294         }
 295
 296         for (i = dindirect_block ; i < uspi->s_apb ; i++) {
 297                 dind = ubh_get_addr32 (dind_bh, i);
 298                 tmp = fs32_to_cpu(sb, *dind);
 299                 if (!tmp)
 300                         continue;
 301                 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
 302                 ubh_mark_buffer_dirty(dind_bh);
 303         }
 304
 305         for (i = 0; i < uspi->s_apb; i++)
 306                 if (*ubh_get_addr32 (dind_bh, i))
 307                         break;
 308         if (i >= uspi->s_apb) {
 309                 if (ubh_max_bcount(dind_bh) != 1)
 310                         retry = 1;
 311                 else {
 312                         tmp = fs32_to_cpu(sb, *p);
 313                         *p = 0;
 314                         inode->i_blocks -= uspi->s_nspb;
 315                         mark_inode_dirty(inode);
 316                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 317                         ubh_bforget(dind_bh);
 318                         dind_bh = NULL;
 319                 }
 320         }
 321         if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
 322                 ubh_ll_rw_block (SWRITE, 1, &dind_bh);
 323                 ubh_wait_on_buffer (dind_bh);
 324         }
 325         ubh_brelse (dind_bh);
 326
 327         UFSD(("EXIT\n"))
 328
 329         return retry;
 330 }
 331
 332 static int ufs_trunc_tindirect (struct inode * inode)
 333 {
 334         struct ufs_inode_info *ufsi = UFS_I(inode);
 335         struct super_block * sb;
 336         struct ufs_sb_private_info * uspi;
 337         struct ufs_buffer_head * tind_bh;
 338         unsigned tindirect_block, tmp, i;
 339         __fs32 * tind, * p;
 340         int retry;
 341
 342         UFSD(("ENTER\n"))
 343
 344         sb = inode->i_sb;
 345         uspi = UFS_SB(sb)->s_uspi;
 346         retry = 0;
 347
 348         tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
 349                 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
 350         p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
 351         if (!(tmp = fs32_to_cpu(sb, *p)))
 352                 return 0;
 353         tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
 354         if (tmp != fs32_to_cpu(sb, *p)) {
 355                 ubh_brelse (tind_bh);
 356                 return 1;
 357         }
 358         if (!tind_bh) {
 359                 *p = 0;
 360                 return 0;
 361         }
 362
 363         for (i = tindirect_block ; i < uspi->s_apb ; i++) {
 364                 tind = ubh_get_addr32 (tind_bh, i);
 365                 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
 366                         uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
 367                 ubh_mark_buffer_dirty(tind_bh);
 368         }
 369         for (i = 0; i < uspi->s_apb; i++)
 370                 if (*ubh_get_addr32 (tind_bh, i))
 371                         break;
 372         if (i >= uspi->s_apb) {
 373                 if (ubh_max_bcount(tind_bh) != 1)
 374                         retry = 1;
 375                 else {
 376                         tmp = fs32_to_cpu(sb, *p);
 377                         *p = 0;
 378                         inode->i_blocks -= uspi->s_nspb;
 379                         mark_inode_dirty(inode);
 380                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 381                         ubh_bforget(tind_bh);
 382                         tind_bh = NULL;
 383                 }
 384         }
 385         if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
 386                 ubh_ll_rw_block (SWRITE, 1, &tind_bh);
 387                 ubh_wait_on_buffer (tind_bh);
 388         }
 389         ubh_brelse (tind_bh);
 390
 391         UFSD(("EXIT\n"))
 392         return retry;
 393 }
 394
 395 void ufs_truncate (struct inode * inode)
 396 {
 397         struct ufs_inode_info *ufsi = UFS_I(inode);
 398         struct super_block * sb;
 399         struct ufs_sb_private_info * uspi;
 400         int retry;
 401
 402         UFSD(("ENTER\n"))
 403         sb = inode->i_sb;
 404         uspi = UFS_SB(sb)->s_uspi;
 405
 406         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 407                 return;
 408         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 409                 return;
 410
 411         block_truncate_page(inode->i_mapping,   inode->i_size, ufs_getfrag_block);
 412
 413         lock_kernel();
 414         while (1) {
 415                 retry = ufs_trunc_direct(inode);
 416                 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
 417                         (__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
 418                 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
 419                         (__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
 420                 retry |= ufs_trunc_tindirect (inode);
 421                 if (!retry)
 422                         break;
 423                 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
 424                         ufs_sync_inode (inode);
 425                 blk_run_address_space(inode->i_mapping);
 426                 yield();
 427         }
 428
 429         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 430         ufsi->i_lastfrag = DIRECT_FRAGMENT;
 431         unlock_kernel();
 432         mark_inode_dirty(inode);
 433         UFSD(("EXIT\n"))
 434 }