fs/ext4/migrate.c

   1 /*
   2  * Copyright IBM Corporation, 2007
   3  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of version 2.1 of the GNU Lesser General Public License
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/ext4_jbd2.h>
  17 #include <linux/ext4_fs_extents.h>
  18
  19 /*
  20  * The contiguous blocks details which can be
  21  * represented by a single extent
  22  */
  23 struct list_blocks_struct {
  24         ext4_lblk_t first_block, last_block;
  25         ext4_fsblk_t first_pblock, last_pblock;
  26 };
  27
  28 static int finish_range(handle_t *handle, struct inode *inode,
  29                                 struct list_blocks_struct *lb)
  30
  31 {
  32         int retval = 0, needed;
  33         struct ext4_extent newext;
  34         struct ext4_ext_path *path;
  35         if (lb->first_pblock == 0)
  36                 return 0;
  37
  38         /* Add the extent to temp inode*/
  39         newext.ee_block = cpu_to_le32(lb->first_block);
  40         newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
  41         ext4_ext_store_pblock(&newext, lb->first_pblock);
  42         path = ext4_ext_find_extent(inode, lb->first_block, NULL);
  43
  44         if (IS_ERR(path)) {
  45                 retval = PTR_ERR(path);
  46                 goto err_out;
  47         }
  48
  49         /*
  50          * Calculate the credit needed to inserting this extent
  51          * Since we are doing this in loop we may accumalate extra
  52          * credit. But below we try to not accumalate too much
  53          * of them by restarting the journal.
  54          */
  55         needed = ext4_ext_calc_credits_for_insert(inode, path);
  56
  57         /*
  58          * Make sure the credit we accumalated is not really high
  59          */
  60         if (needed && handle->h_buffer_credits >= EXT4_RESERVE_TRANS_BLOCKS) {
  61                 retval = ext4_journal_restart(handle, needed);
  62                 if (retval)
  63                         goto err_out;
  64         }
  65         if (needed) {
  66                 retval = ext4_journal_extend(handle, needed);
  67                 if (retval != 0) {
  68                         /*
  69                          * IF not able to extend the journal restart the journal
  70                          */
  71                         retval = ext4_journal_restart(handle, needed);
  72                         if (retval)
  73                                 goto err_out;
  74                 }
  75         }
  76         retval = ext4_ext_insert_extent(handle, inode, path, &newext);
  77 err_out:
  78         lb->first_pblock = 0;
  79         return retval;
  80 }
  81
  82 static int update_extent_range(handle_t *handle, struct inode *inode,
  83                                 ext4_fsblk_t pblock, ext4_lblk_t blk_num,
  84                                 struct list_blocks_struct *lb)
  85 {
  86         int retval;
  87         /*
  88          * See if we can add on to the existing range (if it exists)
  89          */
  90         if (lb->first_pblock &&
  91                 (lb->last_pblock+1 == pblock) &&
  92                 (lb->last_block+1 == blk_num)) {
  93                 lb->last_pblock = pblock;
  94                 lb->last_block = blk_num;
  95                 return 0;
  96         }
  97         /*
  98          * Start a new range.
  99          */
 100         retval = finish_range(handle, inode, lb);
 101         lb->first_pblock = lb->last_pblock = pblock;
 102         lb->first_block = lb->last_block = blk_num;
 103
 104         return retval;
 105 }
 106
 107 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
 108                                    ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 109                                    struct list_blocks_struct *lb)
 110 {
 111         struct buffer_head *bh;
 112         __le32 *i_data;
 113         int i, retval = 0;
 114         ext4_lblk_t blk_count = *blk_nump;
 115         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 116
 117         if (!pblock) {
 118                 /* Only update the file block number */
 119                 *blk_nump += max_entries;
 120                 return 0;
 121         }
 122
 123         bh = sb_bread(inode->i_sb, pblock);
 124         if (!bh)
 125                 return -EIO;
 126
 127         i_data = (__le32 *)bh->b_data;
 128         for (i = 0; i < max_entries; i++, blk_count++) {
 129                 if (i_data[i]) {
 130                         retval = update_extent_range(handle, inode,
 131                                                 le32_to_cpu(i_data[i]),
 132                                                 blk_count, lb);
 133                         if (retval)
 134                                 break;
 135                 }
 136         }
 137
 138         /* Update the file block number */
 139         *blk_nump = blk_count;
 140         put_bh(bh);
 141         return retval;
 142
 143 }
 144
 145 static int update_dind_extent_range(handle_t *handle, struct inode *inode,
 146                                     ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 147                                     struct list_blocks_struct *lb)
 148 {
 149         struct buffer_head *bh;
 150         __le32 *i_data;
 151         int i, retval = 0;
 152         ext4_lblk_t blk_count = *blk_nump;
 153         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 154
 155         if (!pblock) {
 156                 /* Only update the file block number */
 157                 *blk_nump += max_entries * max_entries;
 158                 return 0;
 159         }
 160         bh = sb_bread(inode->i_sb, pblock);
 161         if (!bh)
 162                 return -EIO;
 163
 164         i_data = (__le32 *)bh->b_data;
 165         for (i = 0; i < max_entries; i++) {
 166                 if (i_data[i]) {
 167                         retval = update_ind_extent_range(handle, inode,
 168                                                 le32_to_cpu(i_data[i]),
 169                                                 &blk_count, lb);
 170                         if (retval)
 171                                 break;
 172                 } else {
 173                         /* Only update the file block number */
 174                         blk_count += max_entries;
 175                 }
 176         }
 177
 178         /* Update the file block number */
 179         *blk_nump = blk_count;
 180         put_bh(bh);
 181         return retval;
 182
 183 }
 184
 185 static int update_tind_extent_range(handle_t *handle, struct inode *inode,
 186                                      ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 187                                      struct list_blocks_struct *lb)
 188 {
 189         struct buffer_head *bh;
 190         __le32 *i_data;
 191         int i, retval = 0;
 192         ext4_lblk_t blk_count = *blk_nump;
 193         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 194
 195         if (!pblock) {
 196                 /* Only update the file block number */
 197                 *blk_nump += max_entries * max_entries * max_entries;
 198                 return 0;
 199         }
 200         bh = sb_bread(inode->i_sb, pblock);
 201         if (!bh)
 202                 return -EIO;
 203
 204         i_data = (__le32 *)bh->b_data;
 205         for (i = 0; i < max_entries; i++) {
 206                 if (i_data[i]) {
 207                         retval = update_dind_extent_range(handle, inode,
 208                                                 le32_to_cpu(i_data[i]),
 209                                                 &blk_count, lb);
 210                         if (retval)
 211                                 break;
 212                 } else
 213                         /* Only update the file block number */
 214                         blk_count += max_entries * max_entries;
 215         }
 216         /* Update the file block number */
 217         *blk_nump = blk_count;
 218         put_bh(bh);
 219         return retval;
 220
 221 }
 222
 223 static int free_dind_blocks(handle_t *handle,
 224                                 struct inode *inode, __le32 i_data)
 225 {
 226         int i;
 227         __le32 *tmp_idata;
 228         struct buffer_head *bh;
 229         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 230
 231         bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
 232         if (!bh)
 233                 return -EIO;
 234
 235         tmp_idata = (__le32 *)bh->b_data;
 236         for (i = 0; i < max_entries; i++) {
 237                 if (tmp_idata[i])
 238                         ext4_free_blocks(handle, inode,
 239                                         le32_to_cpu(tmp_idata[i]), 1, 1);
 240         }
 241         put_bh(bh);
 242         ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
 243         return 0;
 244 }
 245
 246 static int free_tind_blocks(handle_t *handle,
 247                                 struct inode *inode, __le32 i_data)
 248 {
 249         int i, retval = 0;
 250         __le32 *tmp_idata;
 251         struct buffer_head *bh;
 252         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 253
 254         bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
 255         if (!bh)
 256                 return -EIO;
 257
 258         tmp_idata = (__le32 *)bh->b_data;
 259         for (i = 0; i < max_entries; i++) {
 260                 if (tmp_idata[i]) {
 261                         retval = free_dind_blocks(handle,
 262                                         inode, tmp_idata[i]);
 263                         if (retval) {
 264                                 put_bh(bh);
 265                                 return retval;
 266                         }
 267                 }
 268         }
 269         put_bh(bh);
 270         ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
 271         return 0;
 272 }
 273
 274 static int free_ind_block(handle_t *handle, struct inode *inode)
 275 {
 276         int retval;
 277         struct ext4_inode_info *ei = EXT4_I(inode);
 278
 279         if (ei->i_data[EXT4_IND_BLOCK])
 280                 ext4_free_blocks(handle, inode,
 281                                 le32_to_cpu(ei->i_data[EXT4_IND_BLOCK]), 1, 1);
 282
 283         if (ei->i_data[EXT4_DIND_BLOCK]) {
 284                 retval = free_dind_blocks(handle, inode,
 285                                                 ei->i_data[EXT4_DIND_BLOCK]);
 286                 if (retval)
 287                         return retval;
 288         }
 289
 290         if (ei->i_data[EXT4_TIND_BLOCK]) {
 291                 retval = free_tind_blocks(handle, inode,
 292                                                 ei->i_data[EXT4_TIND_BLOCK]);
 293                 if (retval)
 294                         return retval;
 295         }
 296         return 0;
 297 }
 298
 299 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 300                                 struct inode *tmp_inode, int retval)
 301 {
 302         struct ext4_inode_info *ei = EXT4_I(inode);
 303         struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
 304
 305         retval = free_ind_block(handle, inode);
 306         if (retval)
 307                 goto err_out;
 308
 309         /*
 310          * One credit accounted for writing the
 311          * i_data field of the original inode
 312          */
 313         retval = ext4_journal_extend(handle, 1);
 314         if (retval != 0) {
 315                 retval = ext4_journal_restart(handle, 1);
 316                 if (retval)
 317                         goto err_out;
 318         }
 319
 320         /*
 321          * We have the extent map build with the tmp inode.
 322          * Now copy the i_data across
 323          */
 324         ei->i_flags |= EXT4_EXTENTS_FL;
 325         memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
 326
 327         /*
 328          * Update i_blocks with the new blocks that got
 329          * allocated while adding extents for extent index
 330          * blocks.
 331          *
 332          * While converting to extents we need not
 333          * update the orignal inode i_blocks for extent blocks
 334          * via quota APIs. The quota update happened via tmp_inode already.
 335          */
 336         spin_lock(&inode->i_lock);
 337         inode->i_blocks += tmp_inode->i_blocks;
 338         spin_unlock(&inode->i_lock);
 339
 340         ext4_mark_inode_dirty(handle, inode);
 341 err_out:
 342         return retval;
 343 }
 344
 345 static int free_ext_idx(handle_t *handle, struct inode *inode,
 346                                         struct ext4_extent_idx *ix)
 347 {
 348         int i, retval = 0;
 349         ext4_fsblk_t block;
 350         struct buffer_head *bh;
 351         struct ext4_extent_header *eh;
 352
 353         block = idx_pblock(ix);
 354         bh = sb_bread(inode->i_sb, block);
 355         if (!bh)
 356                 return -EIO;
 357
 358         eh = (struct ext4_extent_header *)bh->b_data;
 359         if (eh->eh_depth != 0) {
 360                 ix = EXT_FIRST_INDEX(eh);
 361                 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 362                         retval = free_ext_idx(handle, inode, ix);
 363                         if (retval)
 364                                 break;
 365                 }
 366         }
 367         put_bh(bh);
 368         ext4_free_blocks(handle, inode, block, 1, 1);
 369         return retval;
 370 }
 371
 372 /*
 373  * Free the extent meta data blocks only
 374  */
 375 static int free_ext_block(handle_t *handle, struct inode *inode)
 376 {
 377         int i, retval = 0;
 378         struct ext4_inode_info *ei = EXT4_I(inode);
 379         struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
 380         struct ext4_extent_idx *ix;
 381         if (eh->eh_depth == 0)
 382                 /*
 383                  * No extra blocks allocated for extent meta data
 384                  */
 385                 return 0;
 386         ix = EXT_FIRST_INDEX(eh);
 387         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 388                 retval = free_ext_idx(handle, inode, ix);
 389                 if (retval)
 390                         return retval;
 391         }
 392         return retval;
 393
 394 }
 395
 396 int ext4_ext_migrate(struct inode *inode, struct file *filp,
 397                                 unsigned int cmd, unsigned long arg)
 398 {
 399         handle_t *handle;
 400         int retval = 0, i;
 401         __le32 *i_data;
 402         ext4_lblk_t blk_count = 0;
 403         struct ext4_inode_info *ei;
 404         struct inode *tmp_inode = NULL;
 405         struct list_blocks_struct lb;
 406         unsigned long max_entries;
 407
 408         if (!test_opt(inode->i_sb, EXTENTS))
 409                 /*
 410                  * if mounted with noextents we don't allow the migrate
 411                  */
 412                 return -EINVAL;
 413
 414         if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
 415                 return -EINVAL;
 416
 417         down_write(&EXT4_I(inode)->i_data_sem);
 418         handle = ext4_journal_start(inode,
 419                                         EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
 420                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
 421                                         2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)
 422                                         + 1);
 423         if (IS_ERR(handle)) {
 424                 retval = PTR_ERR(handle);
 425                 goto err_out;
 426         }
 427         tmp_inode = ext4_new_inode(handle,
 428                                 inode->i_sb->s_root->d_inode,
 429                                 S_IFREG);
 430         if (IS_ERR(tmp_inode)) {
 431                 retval = -ENOMEM;
 432                 ext4_journal_stop(handle);
 433                 tmp_inode = NULL;
 434                 goto err_out;
 435         }
 436         i_size_write(tmp_inode, i_size_read(inode));
 437         /*
 438          * We don't want the inode to be reclaimed
 439          * if we got interrupted in between. We have
 440          * this tmp inode carrying reference to the
 441          * data blocks of the original file. We set
 442          * the i_nlink to zero at the last stage after
 443          * switching the original file to extent format
 444          */
 445         tmp_inode->i_nlink = 1;
 446
 447         ext4_ext_tree_init(handle, tmp_inode);
 448         ext4_orphan_add(handle, tmp_inode);
 449         ext4_journal_stop(handle);
 450
 451         ei = EXT4_I(inode);
 452         i_data = ei->i_data;
 453         memset(&lb, 0, sizeof(lb));
 454
 455         /* 32 bit block address 4 bytes */
 456         max_entries = inode->i_sb->s_blocksize >> 2;
 457
 458         /*
 459          * start with one credit accounted for
 460          * superblock modification.
 461          *
 462          * For the tmp_inode we already have commited the
 463          * trascation that created the inode. Later as and
 464          * when we add extents we extent the journal
 465          */
 466         handle = ext4_journal_start(inode, 1);
 467         for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
 468                 if (i_data[i]) {
 469                         retval = update_extent_range(handle, tmp_inode,
 470                                                 le32_to_cpu(i_data[i]),
 471                                                 blk_count, &lb);
 472                         if (retval)
 473                                 goto err_out;
 474                 }
 475         }
 476         if (i_data[EXT4_IND_BLOCK]) {
 477                 retval = update_ind_extent_range(handle, tmp_inode,
 478                                         le32_to_cpu(i_data[EXT4_IND_BLOCK]),
 479                                         &blk_count, &lb);
 480                         if (retval)
 481                                 goto err_out;
 482         } else
 483                 blk_count +=  max_entries;
 484         if (i_data[EXT4_DIND_BLOCK]) {
 485                 retval = update_dind_extent_range(handle, tmp_inode,
 486                                         le32_to_cpu(i_data[EXT4_DIND_BLOCK]),
 487                                         &blk_count, &lb);
 488                         if (retval)
 489                                 goto err_out;
 490         } else
 491                 blk_count += max_entries * max_entries;
 492         if (i_data[EXT4_TIND_BLOCK]) {
 493                 retval = update_tind_extent_range(handle, tmp_inode,
 494                                         le32_to_cpu(i_data[EXT4_TIND_BLOCK]),
 495                                         &blk_count, &lb);
 496                         if (retval)
 497                                 goto err_out;
 498         }
 499         /*
 500          * Build the last extent
 501          */
 502         retval = finish_range(handle, tmp_inode, &lb);
 503 err_out:
 504         /*
 505          * We are either freeing extent information or indirect
 506          * blocks. During this we touch superblock, group descriptor
 507          * and block bitmap. Later we mark the tmp_inode dirty
 508          * via ext4_ext_tree_init. So allocate a credit of 4
 509          * We may update quota (user and group).
 510          *
 511          * FIXME!! we may be touching bitmaps in different block groups.
 512          */
 513         if (ext4_journal_extend(handle,
 514                         4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)) != 0)
 515                 ext4_journal_restart(handle,
 516                                 4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
 517         if (retval)
 518                 /*
 519                  * Failure case delete the extent information with the
 520                  * tmp_inode
 521                  */
 522                 free_ext_block(handle, tmp_inode);
 523         else
 524                 retval = ext4_ext_swap_inode_data(handle, inode,
 525                                                         tmp_inode, retval);
 526
 527         /*
 528          * Mark the tmp_inode as of size zero
 529          */
 530         i_size_write(tmp_inode, 0);
 531
 532         /*
 533          * set the  i_blocks count to zero
 534          * so that the ext4_delete_inode does the
 535          * right job
 536          *
 537          * We don't need to take the i_lock because
 538          * the inode is not visible to user space.
 539          */
 540         tmp_inode->i_blocks = 0;
 541
 542         /* Reset the extent details */
 543         ext4_ext_tree_init(handle, tmp_inode);
 544
 545         /*
 546          * Set the i_nlink to zero so that
 547          * generic_drop_inode really deletes the
 548          * inode
 549          */
 550         tmp_inode->i_nlink = 0;
 551
 552         ext4_journal_stop(handle);
 553
 554         up_write(&EXT4_I(inode)->i_data_sem);
 555
 556         if (tmp_inode)
 557                 iput(tmp_inode);
 558
 559         return retval;
 560 }