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 #include <linux/errno.h>
  33 #include <linux/fs.h>
  34 #include <linux/ufs_fs.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/time.h>
  37 #include <linux/stat.h>
  38 #include <linux/string.h>
  39 #include <linux/smp_lock.h>
  40 #include <linux/buffer_head.h>
  41 #include <linux/blkdev.h>
  42 #include <linux/sched.h>
  43
  44 #include "swab.h"
  45 #include "util.h"
  46
  47 #undef UFS_TRUNCATE_DEBUG
  48
  49 #ifdef UFS_TRUNCATE_DEBUG
  50 #define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
  51 #else
  52 #define UFSD(x)
  53 #endif
  54
  55 /*
  56  * Secure deletion currently doesn't work. It interacts very badly
  57  * with buffers shared with memory mappings, and for that reason
  58  * can't be done in the truncate() routines. It should instead be
  59  * done separately in "release()" before calling the truncate routines
  60  * that will release the actual file blocks.
  61  *
  62  *              Linus
  63  */
  64
  65 #define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
  66 #define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
  67
  68 #define DATA_BUFFER_USED(bh) \
  69         (atomic_read(&bh->b_count)>1 || buffer_locked(bh))
  70
  71 static int ufs_trunc_direct (struct inode * inode)
  72 {
  73         struct ufs_inode_info *ufsi = UFS_I(inode);
  74         struct super_block * sb;
  75         struct ufs_sb_private_info * uspi;
  76         struct buffer_head * bh;
  77         __fs32 * p;
  78         unsigned frag1, frag2, frag3, frag4, block1, block2;
  79         unsigned frag_to_free, free_count;
  80         unsigned i, j, tmp;
  81         int retry;
  82
  83         UFSD(("ENTER\n"))
  84
  85         sb = inode->i_sb;
  86         uspi = UFS_SB(sb)->s_uspi;
  87
  88         frag_to_free = 0;
  89         free_count = 0;
  90         retry = 0;
  91
  92         frag1 = DIRECT_FRAGMENT;
  93         frag4 = min_t(u32, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
  94         frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
  95         frag3 = frag4 & ~uspi->s_fpbmask;
  96         block1 = block2 = 0;
  97         if (frag2 > frag3) {
  98                 frag2 = frag4;
  99                 frag3 = frag4 = 0;
 100         }
 101         else if (frag2 < frag3) {
 102                 block1 = ufs_fragstoblks (frag2);
 103                 block2 = ufs_fragstoblks (frag3);
 104         }
 105
 106         UFSD(("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4))
 107
 108         if (frag1 >= frag2)
 109                 goto next1;
 110
 111         /*
 112          * Free first free fragments
 113          */
 114         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag1);
 115         tmp = fs32_to_cpu(sb, *p);
 116         if (!tmp )
 117                 ufs_panic (sb, "ufs_trunc_direct", "internal error");
 118         frag1 = ufs_fragnum (frag1);
 119         frag2 = ufs_fragnum (frag2);
 120         for (j = frag1; j < frag2; j++) {
 121                 bh = sb_find_get_block (sb, tmp + j);
 122                 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
 123                         retry = 1;
 124                         brelse (bh);
 125                         goto next1;
 126                 }
 127                 bforget (bh);
 128         }
 129         inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
 130         mark_inode_dirty(inode);
 131         ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
 132         frag_to_free = tmp + frag1;
 133
 134 next1:
 135         /*
 136          * Free whole blocks
 137          */
 138         for (i = block1 ; i < block2; i++) {
 139                 p = ufsi->i_u1.i_data + i;
 140                 tmp = fs32_to_cpu(sb, *p);
 141                 if (!tmp)
 142                         continue;
 143                 for (j = 0; j < uspi->s_fpb; j++) {
 144                         bh = sb_find_get_block(sb, tmp + j);
 145                         if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
 146                                 retry = 1;
 147                                 brelse (bh);
 148                                 goto next2;
 149                         }
 150                         bforget (bh);
 151                 }
 152                 *p = 0;
 153                 inode->i_blocks -= uspi->s_nspb;
 154                 mark_inode_dirty(inode);
 155                 if (free_count == 0) {
 156                         frag_to_free = tmp;
 157                         free_count = uspi->s_fpb;
 158                 } else if (free_count > 0 && frag_to_free == tmp - free_count)
 159                         free_count += uspi->s_fpb;
 160                 else {
 161                         ufs_free_blocks (inode, frag_to_free, free_count);
 162                         frag_to_free = tmp;
 163                         free_count = uspi->s_fpb;
 164                 }
 165 next2:;
 166         }
 167
 168         if (free_count > 0)
 169                 ufs_free_blocks (inode, frag_to_free, free_count);
 170
 171         if (frag3 >= frag4)
 172                 goto next3;
 173
 174         /*
 175          * Free last free fragments
 176          */
 177         p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
 178         tmp = fs32_to_cpu(sb, *p);
 179         if (!tmp )
 180                 ufs_panic(sb, "ufs_truncate_direct", "internal error");
 181         frag4 = ufs_fragnum (frag4);
 182         for (j = 0; j < frag4; j++) {
 183                 bh = sb_find_get_block (sb, tmp + j);
 184                 if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
 185                         retry = 1;
 186                         brelse (bh);
 187                         goto next1;
 188                 }
 189                 bforget (bh);
 190         }
 191         *p = 0;
 192         inode->i_blocks -= frag4 << uspi->s_nspfshift;
 193         mark_inode_dirty(inode);
 194         ufs_free_fragments (inode, tmp, frag4);
 195  next3:
 196
 197         UFSD(("EXIT\n"))
 198         return retry;
 199 }
 200
 201
 202 static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
 203 {
 204         struct super_block * sb;
 205         struct ufs_sb_private_info * uspi;
 206         struct ufs_buffer_head * ind_ubh;
 207         struct buffer_head * bh;
 208         __fs32 * ind;
 209         unsigned indirect_block, i, j, tmp;
 210         unsigned frag_to_free, free_count;
 211         int retry;
 212
 213         UFSD(("ENTER\n"))
 214
 215         sb = inode->i_sb;
 216         uspi = UFS_SB(sb)->s_uspi;
 217
 218         frag_to_free = 0;
 219         free_count = 0;
 220         retry = 0;
 221
 222         tmp = fs32_to_cpu(sb, *p);
 223         if (!tmp)
 224                 return 0;
 225         ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
 226         if (tmp != fs32_to_cpu(sb, *p)) {
 227                 ubh_brelse (ind_ubh);
 228                 return 1;
 229         }
 230         if (!ind_ubh) {
 231                 *p = 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 = fs32_to_cpu(sb, *ind);
 239                 if (!tmp)
 240                         continue;
 241                 for (j = 0; j < uspi->s_fpb; j++) {
 242                         bh = sb_find_get_block(sb, tmp + j);
 243                         if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *ind)) {
 244                                 retry = 1;
 245                                 brelse (bh);
 246                                 goto next;
 247                         }
 248                         bforget (bh);
 249                 }
 250                 *ind = 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 (*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 = fs32_to_cpu(sb, *p);
 279                         *p = 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 (SWRITE, 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, __fs32 *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         __fs32 * dind;
 305         int retry = 0;
 306
 307         UFSD(("ENTER\n"))
 308
 309         sb = inode->i_sb;
 310         uspi = UFS_SB(sb)->s_uspi;
 311
 312         dindirect_block = (DIRECT_BLOCK > offset)
 313                 ? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
 314         retry = 0;
 315
 316         tmp = fs32_to_cpu(sb, *p);
 317         if (!tmp)
 318                 return 0;
 319         dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
 320         if (tmp != fs32_to_cpu(sb, *p)) {
 321                 ubh_brelse (dind_bh);
 322                 return 1;
 323         }
 324         if (!dind_bh) {
 325                 *p = 0;
 326                 return 0;
 327         }
 328
 329         for (i = dindirect_block ; i < uspi->s_apb ; i++) {
 330                 dind = ubh_get_addr32 (dind_bh, i);
 331                 tmp = fs32_to_cpu(sb, *dind);
 332                 if (!tmp)
 333                         continue;
 334                 retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
 335                 ubh_mark_buffer_dirty(dind_bh);
 336         }
 337
 338         for (i = 0; i < uspi->s_apb; i++)
 339                 if (*ubh_get_addr32 (dind_bh, i))
 340                         break;
 341         if (i >= uspi->s_apb) {
 342                 if (ubh_max_bcount(dind_bh) != 1)
 343                         retry = 1;
 344                 else {
 345                         tmp = fs32_to_cpu(sb, *p);
 346                         *p = 0;
 347                         inode->i_blocks -= uspi->s_nspb;
 348                         mark_inode_dirty(inode);
 349                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 350                         ubh_bforget(dind_bh);
 351                         dind_bh = NULL;
 352                 }
 353         }
 354         if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
 355                 ubh_ll_rw_block (SWRITE, 1, &dind_bh);
 356                 ubh_wait_on_buffer (dind_bh);
 357         }
 358         ubh_brelse (dind_bh);
 359
 360         UFSD(("EXIT\n"))
 361
 362         return retry;
 363 }
 364
 365 static int ufs_trunc_tindirect (struct inode * inode)
 366 {
 367         struct ufs_inode_info *ufsi = UFS_I(inode);
 368         struct super_block * sb;
 369         struct ufs_sb_private_info * uspi;
 370         struct ufs_buffer_head * tind_bh;
 371         unsigned tindirect_block, tmp, i;
 372         __fs32 * tind, * p;
 373         int retry;
 374
 375         UFSD(("ENTER\n"))
 376
 377         sb = inode->i_sb;
 378         uspi = UFS_SB(sb)->s_uspi;
 379         retry = 0;
 380
 381         tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
 382                 ? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
 383         p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
 384         if (!(tmp = fs32_to_cpu(sb, *p)))
 385                 return 0;
 386         tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
 387         if (tmp != fs32_to_cpu(sb, *p)) {
 388                 ubh_brelse (tind_bh);
 389                 return 1;
 390         }
 391         if (!tind_bh) {
 392                 *p = 0;
 393                 return 0;
 394         }
 395
 396         for (i = tindirect_block ; i < uspi->s_apb ; i++) {
 397                 tind = ubh_get_addr32 (tind_bh, i);
 398                 retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
 399                         uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
 400                 ubh_mark_buffer_dirty(tind_bh);
 401         }
 402         for (i = 0; i < uspi->s_apb; i++)
 403                 if (*ubh_get_addr32 (tind_bh, i))
 404                         break;
 405         if (i >= uspi->s_apb) {
 406                 if (ubh_max_bcount(tind_bh) != 1)
 407                         retry = 1;
 408                 else {
 409                         tmp = fs32_to_cpu(sb, *p);
 410                         *p = 0;
 411                         inode->i_blocks -= uspi->s_nspb;
 412                         mark_inode_dirty(inode);
 413                         ufs_free_blocks (inode, tmp, uspi->s_fpb);
 414                         ubh_bforget(tind_bh);
 415                         tind_bh = NULL;
 416                 }
 417         }
 418         if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
 419                 ubh_ll_rw_block (SWRITE, 1, &tind_bh);
 420                 ubh_wait_on_buffer (tind_bh);
 421         }
 422         ubh_brelse (tind_bh);
 423
 424         UFSD(("EXIT\n"))
 425         return retry;
 426 }
 427
 428 void ufs_truncate (struct inode * inode)
 429 {
 430         struct ufs_inode_info *ufsi = UFS_I(inode);
 431         struct super_block * sb;
 432         struct ufs_sb_private_info * uspi;
 433         struct buffer_head * bh;
 434         unsigned offset;
 435         int err, retry;
 436
 437         UFSD(("ENTER\n"))
 438         sb = inode->i_sb;
 439         uspi = UFS_SB(sb)->s_uspi;
 440
 441         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
 442                 return;
 443         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 444                 return;
 445         lock_kernel();
 446         while (1) {
 447                 retry = ufs_trunc_direct(inode);
 448                 retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
 449                         (__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
 450                 retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
 451                         (__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
 452                 retry |= ufs_trunc_tindirect (inode);
 453                 if (!retry)
 454                         break;
 455                 if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
 456                         ufs_sync_inode (inode);
 457                 blk_run_address_space(inode->i_mapping);
 458                 yield();
 459         }
 460         offset = inode->i_size & uspi->s_fshift;
 461         if (offset) {
 462                 bh = ufs_bread (inode, inode->i_size >> uspi->s_fshift, 0, &err);
 463                 if (bh) {
 464                         memset (bh->b_data + offset, 0, uspi->s_fsize - offset);
 465                         mark_buffer_dirty (bh);
 466                         brelse (bh);
 467                 }
 468         }
 469         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 470         ufsi->i_lastfrag = DIRECT_FRAGMENT;
 471         unlock_kernel();
 472         mark_inode_dirty(inode);
 473         UFSD(("EXIT\n"))
 474 }