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/slab.h>
  17 #include "ext4_jbd2.h"
  18 #include "ext4_extents.h"
  19
  20 /*
  21  * The contiguous blocks details which can be
  22  * represented by a single extent
  23  */
  24 struct list_blocks_struct {
  25         ext4_lblk_t first_block, last_block;
  26         ext4_fsblk_t first_pblock, last_pblock;
  27 };
  28
  29 static int finish_range(handle_t *handle, struct inode *inode,
  30                                 struct list_blocks_struct *lb)
  31
  32 {
  33         int retval = 0, needed;
  34         struct ext4_extent newext;
  35         struct ext4_ext_path *path;
  36         if (lb->first_pblock == 0)
  37                 return 0;
  38
  39         /* Add the extent to temp inode*/
  40         newext.ee_block = cpu_to_le32(lb->first_block);
  41         newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
  42         ext4_ext_store_pblock(&newext, lb->first_pblock);
  43         path = ext4_ext_find_extent(inode, lb->first_block, NULL);
  44
  45         if (IS_ERR(path)) {
  46                 retval = PTR_ERR(path);
  47                 path = NULL;
  48                 goto err_out;
  49         }
  50
  51         /*
  52          * Calculate the credit needed to inserting this extent
  53          * Since we are doing this in loop we may accumalate extra
  54          * credit. But below we try to not accumalate too much
  55          * of them by restarting the journal.
  56          */
  57         needed = ext4_ext_calc_credits_for_single_extent(inode,
  58                     lb->last_block - lb->first_block + 1, path);
  59
  60         /*
  61          * Make sure the credit we accumalated is not really high
  62          */
  63         if (needed && ext4_handle_has_enough_credits(handle,
  64                                                 EXT4_RESERVE_TRANS_BLOCKS)) {
  65                 retval = ext4_journal_restart(handle, needed);
  66                 if (retval)
  67                         goto err_out;
  68         } else if (needed) {
  69                 retval = ext4_journal_extend(handle, needed);
  70                 if (retval) {
  71                         /*
  72                          * IF not able to extend the journal restart the journal
  73                          */
  74                         retval = ext4_journal_restart(handle, needed);
  75                         if (retval)
  76                                 goto err_out;
  77                 }
  78         }
  79         retval = ext4_ext_insert_extent(handle, inode, path, &newext, 0);
  80 err_out:
  81         if (path) {
  82                 ext4_ext_drop_refs(path);
  83                 kfree(path);
  84         }
  85         lb->first_pblock = 0;
  86         return retval;
  87 }
  88
  89 static int update_extent_range(handle_t *handle, struct inode *inode,
  90                                 ext4_fsblk_t pblock, ext4_lblk_t blk_num,
  91                                 struct list_blocks_struct *lb)
  92 {
  93         int retval;
  94         /*
  95          * See if we can add on to the existing range (if it exists)
  96          */
  97         if (lb->first_pblock &&
  98                 (lb->last_pblock+1 == pblock) &&
  99                 (lb->last_block+1 == blk_num)) {
 100                 lb->last_pblock = pblock;
 101                 lb->last_block = blk_num;
 102                 return 0;
 103         }
 104         /*
 105          * Start a new range.
 106          */
 107         retval = finish_range(handle, inode, lb);
 108         lb->first_pblock = lb->last_pblock = pblock;
 109         lb->first_block = lb->last_block = blk_num;
 110
 111         return retval;
 112 }
 113
 114 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
 115                                    ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 116                                    struct list_blocks_struct *lb)
 117 {
 118         struct buffer_head *bh;
 119         __le32 *i_data;
 120         int i, retval = 0;
 121         ext4_lblk_t blk_count = *blk_nump;
 122         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 123
 124         if (!pblock) {
 125                 /* Only update the file block number */
 126                 *blk_nump += max_entries;
 127                 return 0;
 128         }
 129
 130         bh = sb_bread(inode->i_sb, pblock);
 131         if (!bh)
 132                 return -EIO;
 133
 134         i_data = (__le32 *)bh->b_data;
 135         for (i = 0; i < max_entries; i++, blk_count++) {
 136                 if (i_data[i]) {
 137                         retval = update_extent_range(handle, inode,
 138                                                 le32_to_cpu(i_data[i]),
 139                                                 blk_count, lb);
 140                         if (retval)
 141                                 break;
 142                 }
 143         }
 144
 145         /* Update the file block number */
 146         *blk_nump = blk_count;
 147         put_bh(bh);
 148         return retval;
 149
 150 }
 151
 152 static int update_dind_extent_range(handle_t *handle, struct inode *inode,
 153                                     ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 154                                     struct list_blocks_struct *lb)
 155 {
 156         struct buffer_head *bh;
 157         __le32 *i_data;
 158         int i, retval = 0;
 159         ext4_lblk_t blk_count = *blk_nump;
 160         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 161
 162         if (!pblock) {
 163                 /* Only update the file block number */
 164                 *blk_nump += max_entries * max_entries;
 165                 return 0;
 166         }
 167         bh = sb_bread(inode->i_sb, pblock);
 168         if (!bh)
 169                 return -EIO;
 170
 171         i_data = (__le32 *)bh->b_data;
 172         for (i = 0; i < max_entries; i++) {
 173                 if (i_data[i]) {
 174                         retval = update_ind_extent_range(handle, inode,
 175                                                 le32_to_cpu(i_data[i]),
 176                                                 &blk_count, lb);
 177                         if (retval)
 178                                 break;
 179                 } else {
 180                         /* Only update the file block number */
 181                         blk_count += max_entries;
 182                 }
 183         }
 184
 185         /* Update the file block number */
 186         *blk_nump = blk_count;
 187         put_bh(bh);
 188         return retval;
 189
 190 }
 191
 192 static int update_tind_extent_range(handle_t *handle, struct inode *inode,
 193                                      ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
 194                                      struct list_blocks_struct *lb)
 195 {
 196         struct buffer_head *bh;
 197         __le32 *i_data;
 198         int i, retval = 0;
 199         ext4_lblk_t blk_count = *blk_nump;
 200         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 201
 202         if (!pblock) {
 203                 /* Only update the file block number */
 204                 *blk_nump += max_entries * max_entries * max_entries;
 205                 return 0;
 206         }
 207         bh = sb_bread(inode->i_sb, pblock);
 208         if (!bh)
 209                 return -EIO;
 210
 211         i_data = (__le32 *)bh->b_data;
 212         for (i = 0; i < max_entries; i++) {
 213                 if (i_data[i]) {
 214                         retval = update_dind_extent_range(handle, inode,
 215                                                 le32_to_cpu(i_data[i]),
 216                                                 &blk_count, lb);
 217                         if (retval)
 218                                 break;
 219                 } else
 220                         /* Only update the file block number */
 221                         blk_count += max_entries * max_entries;
 222         }
 223         /* Update the file block number */
 224         *blk_nump = blk_count;
 225         put_bh(bh);
 226         return retval;
 227
 228 }
 229
 230 static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
 231 {
 232         int retval = 0, needed;
 233
 234         if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
 235                 return 0;
 236         /*
 237          * We are freeing a blocks. During this we touch
 238          * superblock, group descriptor and block bitmap.
 239          * So allocate a credit of 3. We may update
 240          * quota (user and group).
 241          */
 242         needed = 3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
 243
 244         if (ext4_journal_extend(handle, needed) != 0)
 245                 retval = ext4_journal_restart(handle, needed);
 246
 247         return retval;
 248 }
 249
 250 static int free_dind_blocks(handle_t *handle,
 251                                 struct inode *inode, __le32 i_data)
 252 {
 253         int i;
 254         __le32 *tmp_idata;
 255         struct buffer_head *bh;
 256         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 257
 258         bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
 259         if (!bh)
 260                 return -EIO;
 261
 262         tmp_idata = (__le32 *)bh->b_data;
 263         for (i = 0; i < max_entries; i++) {
 264                 if (tmp_idata[i]) {
 265                         extend_credit_for_blkdel(handle, inode);
 266                         ext4_free_blocks(handle, inode, NULL,
 267                                          le32_to_cpu(tmp_idata[i]), 1,
 268                                          EXT4_FREE_BLOCKS_METADATA |
 269                                          EXT4_FREE_BLOCKS_FORGET);
 270                 }
 271         }
 272         put_bh(bh);
 273         extend_credit_for_blkdel(handle, inode);
 274         ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
 275                          EXT4_FREE_BLOCKS_METADATA |
 276                          EXT4_FREE_BLOCKS_FORGET);
 277         return 0;
 278 }
 279
 280 static int free_tind_blocks(handle_t *handle,
 281                                 struct inode *inode, __le32 i_data)
 282 {
 283         int i, retval = 0;
 284         __le32 *tmp_idata;
 285         struct buffer_head *bh;
 286         unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
 287
 288         bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
 289         if (!bh)
 290                 return -EIO;
 291
 292         tmp_idata = (__le32 *)bh->b_data;
 293         for (i = 0; i < max_entries; i++) {
 294                 if (tmp_idata[i]) {
 295                         retval = free_dind_blocks(handle,
 296                                         inode, tmp_idata[i]);
 297                         if (retval) {
 298                                 put_bh(bh);
 299                                 return retval;
 300                         }
 301                 }
 302         }
 303         put_bh(bh);
 304         extend_credit_for_blkdel(handle, inode);
 305         ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
 306                          EXT4_FREE_BLOCKS_METADATA |
 307                          EXT4_FREE_BLOCKS_FORGET);
 308         return 0;
 309 }
 310
 311 static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
 312 {
 313         int retval;
 314
 315         /* ei->i_data[EXT4_IND_BLOCK] */
 316         if (i_data[0]) {
 317                 extend_credit_for_blkdel(handle, inode);
 318                 ext4_free_blocks(handle, inode, NULL,
 319                                 le32_to_cpu(i_data[0]), 1,
 320                                  EXT4_FREE_BLOCKS_METADATA |
 321                                  EXT4_FREE_BLOCKS_FORGET);
 322         }
 323
 324         /* ei->i_data[EXT4_DIND_BLOCK] */
 325         if (i_data[1]) {
 326                 retval = free_dind_blocks(handle, inode, i_data[1]);
 327                 if (retval)
 328                         return retval;
 329         }
 330
 331         /* ei->i_data[EXT4_TIND_BLOCK] */
 332         if (i_data[2]) {
 333                 retval = free_tind_blocks(handle, inode, i_data[2]);
 334                 if (retval)
 335                         return retval;
 336         }
 337         return 0;
 338 }
 339
 340 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 341                                                 struct inode *tmp_inode)
 342 {
 343         int retval;
 344         __le32  i_data[3];
 345         struct ext4_inode_info *ei = EXT4_I(inode);
 346         struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
 347
 348         /*
 349          * One credit accounted for writing the
 350          * i_data field of the original inode
 351          */
 352         retval = ext4_journal_extend(handle, 1);
 353         if (retval) {
 354                 retval = ext4_journal_restart(handle, 1);
 355                 if (retval)
 356                         goto err_out;
 357         }
 358
 359         i_data[0] = ei->i_data[EXT4_IND_BLOCK];
 360         i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
 361         i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
 362
 363         down_write(&EXT4_I(inode)->i_data_sem);
 364         /*
 365          * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
 366          * happened after we started the migrate. We need to
 367          * fail the migrate
 368          */
 369         if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
 370                 retval = -EAGAIN;
 371                 up_write(&EXT4_I(inode)->i_data_sem);
 372                 goto err_out;
 373         } else
 374                 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 375         /*
 376          * We have the extent map build with the tmp inode.
 377          * Now copy the i_data across
 378          */
 379         ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS);
 380         memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
 381
 382         /*
 383          * Update i_blocks with the new blocks that got
 384          * allocated while adding extents for extent index
 385          * blocks.
 386          *
 387          * While converting to extents we need not
 388          * update the orignal inode i_blocks for extent blocks
 389          * via quota APIs. The quota update happened via tmp_inode already.
 390          */
 391         spin_lock(&inode->i_lock);
 392         inode->i_blocks += tmp_inode->i_blocks;
 393         spin_unlock(&inode->i_lock);
 394         up_write(&EXT4_I(inode)->i_data_sem);
 395
 396         /*
 397          * We mark the inode dirty after, because we decrement the
 398          * i_blocks when freeing the indirect meta-data blocks
 399          */
 400         retval = free_ind_block(handle, inode, i_data);
 401         ext4_mark_inode_dirty(handle, inode);
 402
 403 err_out:
 404         return retval;
 405 }
 406
 407 static int free_ext_idx(handle_t *handle, struct inode *inode,
 408                                         struct ext4_extent_idx *ix)
 409 {
 410         int i, retval = 0;
 411         ext4_fsblk_t block;
 412         struct buffer_head *bh;
 413         struct ext4_extent_header *eh;
 414
 415         block = ext4_idx_pblock(ix);
 416         bh = sb_bread(inode->i_sb, block);
 417         if (!bh)
 418                 return -EIO;
 419
 420         eh = (struct ext4_extent_header *)bh->b_data;
 421         if (eh->eh_depth != 0) {
 422                 ix = EXT_FIRST_INDEX(eh);
 423                 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 424                         retval = free_ext_idx(handle, inode, ix);
 425                         if (retval)
 426                                 break;
 427                 }
 428         }
 429         put_bh(bh);
 430         extend_credit_for_blkdel(handle, inode);
 431         ext4_free_blocks(handle, inode, NULL, block, 1,
 432                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
 433         return retval;
 434 }
 435
 436 /*
 437  * Free the extent meta data blocks only
 438  */
 439 static int free_ext_block(handle_t *handle, struct inode *inode)
 440 {
 441         int i, retval = 0;
 442         struct ext4_inode_info *ei = EXT4_I(inode);
 443         struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
 444         struct ext4_extent_idx *ix;
 445         if (eh->eh_depth == 0)
 446                 /*
 447                  * No extra blocks allocated for extent meta data
 448                  */
 449                 return 0;
 450         ix = EXT_FIRST_INDEX(eh);
 451         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
 452                 retval = free_ext_idx(handle, inode, ix);
 453                 if (retval)
 454                         return retval;
 455         }
 456         return retval;
 457
 458 }
 459
 460 int ext4_ext_migrate(struct inode *inode)
 461 {
 462         handle_t *handle;
 463         int retval = 0, i;
 464         __le32 *i_data;
 465         ext4_lblk_t blk_count = 0;
 466         struct ext4_inode_info *ei;
 467         struct inode *tmp_inode = NULL;
 468         struct list_blocks_struct lb;
 469         unsigned long max_entries;
 470         __u32 goal;
 471
 472         /*
 473          * If the filesystem does not support extents, or the inode
 474          * already is extent-based, error out.
 475          */
 476         if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
 477                                        EXT4_FEATURE_INCOMPAT_EXTENTS) ||
 478             (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 479                 return -EINVAL;
 480
 481         if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
 482                 /*
 483                  * don't migrate fast symlink
 484                  */
 485                 return retval;
 486
 487         handle = ext4_journal_start(inode,
 488                                         EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
 489                                         EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
 490                                         EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)
 491                                         + 1);
 492         if (IS_ERR(handle)) {
 493                 retval = PTR_ERR(handle);
 494                 return retval;
 495         }
 496         goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
 497                 EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
 498         tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
 499                                    S_IFREG, NULL, goal);
 500         if (IS_ERR(tmp_inode)) {
 501                 retval = -ENOMEM;
 502                 ext4_journal_stop(handle);
 503                 return retval;
 504         }
 505         i_size_write(tmp_inode, i_size_read(inode));
 506         /*
 507          * Set the i_nlink to zero so it will be deleted later
 508          * when we drop inode reference.
 509          */
 510         tmp_inode->i_nlink = 0;
 511
 512         ext4_ext_tree_init(handle, tmp_inode);
 513         ext4_orphan_add(handle, tmp_inode);
 514         ext4_journal_stop(handle);
 515
 516         /*
 517          * start with one credit accounted for
 518          * superblock modification.
 519          *
 520          * For the tmp_inode we already have commited the
 521          * trascation that created the inode. Later as and
 522          * when we add extents we extent the journal
 523          */
 524         /*
 525          * Even though we take i_mutex we can still cause block
 526          * allocation via mmap write to holes. If we have allocated
 527          * new blocks we fail migrate.  New block allocation will
 528          * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
 529          * with i_data_sem held to prevent racing with block
 530          * allocation.
 531          */
 532         down_read((&EXT4_I(inode)->i_data_sem));
 533         ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
 534         up_read((&EXT4_I(inode)->i_data_sem));
 535
 536         handle = ext4_journal_start(inode, 1);
 537         if (IS_ERR(handle)) {
 538                 /*
 539                  * It is impossible to update on-disk structures without
 540                  * a handle, so just rollback in-core changes and live other
 541                  * work to orphan_list_cleanup()
 542                  */
 543                 ext4_orphan_del(NULL, tmp_inode);
 544                 retval = PTR_ERR(handle);
 545                 goto out;
 546         }
 547
 548         ei = EXT4_I(inode);
 549         i_data = ei->i_data;
 550         memset(&lb, 0, sizeof(lb));
 551
 552         /* 32 bit block address 4 bytes */
 553         max_entries = inode->i_sb->s_blocksize >> 2;
 554         for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
 555                 if (i_data[i]) {
 556                         retval = update_extent_range(handle, tmp_inode,
 557                                                 le32_to_cpu(i_data[i]),
 558                                                 blk_count, &lb);
 559                         if (retval)
 560                                 goto err_out;
 561                 }
 562         }
 563         if (i_data[EXT4_IND_BLOCK]) {
 564                 retval = update_ind_extent_range(handle, tmp_inode,
 565                                         le32_to_cpu(i_data[EXT4_IND_BLOCK]),
 566                                         &blk_count, &lb);
 567                         if (retval)
 568                                 goto err_out;
 569         } else
 570                 blk_count +=  max_entries;
 571         if (i_data[EXT4_DIND_BLOCK]) {
 572                 retval = update_dind_extent_range(handle, tmp_inode,
 573                                         le32_to_cpu(i_data[EXT4_DIND_BLOCK]),
 574                                         &blk_count, &lb);
 575                         if (retval)
 576                                 goto err_out;
 577         } else
 578                 blk_count += max_entries * max_entries;
 579         if (i_data[EXT4_TIND_BLOCK]) {
 580                 retval = update_tind_extent_range(handle, tmp_inode,
 581                                         le32_to_cpu(i_data[EXT4_TIND_BLOCK]),
 582                                         &blk_count, &lb);
 583                         if (retval)
 584                                 goto err_out;
 585         }
 586         /*
 587          * Build the last extent
 588          */
 589         retval = finish_range(handle, tmp_inode, &lb);
 590 err_out:
 591         if (retval)
 592                 /*
 593                  * Failure case delete the extent information with the
 594                  * tmp_inode
 595                  */
 596                 free_ext_block(handle, tmp_inode);
 597         else {
 598                 retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
 599                 if (retval)
 600                         /*
 601                          * if we fail to swap inode data free the extent
 602                          * details of the tmp inode
 603                          */
 604                         free_ext_block(handle, tmp_inode);
 605         }
 606
 607         /* We mark the tmp_inode dirty via ext4_ext_tree_init. */
 608         if (ext4_journal_extend(handle, 1) != 0)
 609                 ext4_journal_restart(handle, 1);
 610
 611         /*
 612          * Mark the tmp_inode as of size zero
 613          */
 614         i_size_write(tmp_inode, 0);
 615
 616         /*
 617          * set the  i_blocks count to zero
 618          * so that the ext4_delete_inode does the
 619          * right job
 620          *
 621          * We don't need to take the i_lock because
 622          * the inode is not visible to user space.
 623          */
 624         tmp_inode->i_blocks = 0;
 625
 626         /* Reset the extent details */
 627         ext4_ext_tree_init(handle, tmp_inode);
 628         ext4_journal_stop(handle);
 629 out:
 630         unlock_new_inode(tmp_inode);
 631         iput(tmp_inode);
 632
 633         return retval;
 634 }