fs/ext4/move_extent.c

   1 /*
   2  * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
   3  * Written by Takashi Sato <t-sato@yk.jp.nec.com>
   4  *            Akira Fujita <a-fujita@rs.jp.nec.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/fs.h>
  17 #include <linux/quotaops.h>
  18 #include "ext4_jbd2.h"
  19 #include "ext4_extents.h"
  20 #include "ext4.h"
  21
  22 /**
  23  * get_ext_path - Find an extent path for designated logical block number.
  24  *
  25  * @inode:      an inode which is searched
  26  * @lblock:     logical block number to find an extent path
  27  * @path:       pointer to an extent path pointer (for output)
  28  *
  29  * ext4_ext_find_extent wrapper. Return 0 on success, or a negative error value
  30  * on failure.
  31  */
  32 static inline int
  33 get_ext_path(struct inode *inode, ext4_lblk_t lblock,
  34                 struct ext4_ext_path **path)
  35 {
  36         int ret = 0;
  37
  38         *path = ext4_ext_find_extent(inode, lblock, *path);
  39         if (IS_ERR(*path)) {
  40                 ret = PTR_ERR(*path);
  41                 *path = NULL;
  42         } else if ((*path)[ext_depth(inode)].p_ext == NULL)
  43                 ret = -ENODATA;
  44
  45         return ret;
  46 }
  47
  48 /**
  49  * copy_extent_status - Copy the extent's initialization status
  50  *
  51  * @src:        an extent for getting initialize status
  52  * @dest:       an extent to be set the status
  53  */
  54 static void
  55 copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest)
  56 {
  57         if (ext4_ext_is_uninitialized(src))
  58                 ext4_ext_mark_uninitialized(dest);
  59         else
  60                 dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest));
  61 }
  62
  63 /**
  64  * mext_next_extent - Search for the next extent and set it to "extent"
  65  *
  66  * @inode:      inode which is searched
  67  * @path:       this will obtain data for the next extent
  68  * @extent:     pointer to the next extent we have just gotten
  69  *
  70  * Search the next extent in the array of ext4_ext_path structure (@path)
  71  * and set it to ext4_extent structure (@extent). In addition, the member of
  72  * @path (->p_ext) also points the next extent. Return 0 on success, 1 if
  73  * ext4_ext_path structure refers to the last extent, or a negative error
  74  * value on failure.
  75  */
  76 static int
  77 mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
  78                       struct ext4_extent **extent)
  79 {
  80         struct ext4_extent_header *eh;
  81         int ppos, leaf_ppos = path->p_depth;
  82
  83         ppos = leaf_ppos;
  84         if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) {
  85                 /* leaf block */
  86                 *extent = ++path[ppos].p_ext;
  87                 path[ppos].p_block = ext_pblock(path[ppos].p_ext);
  88                 return 0;
  89         }
  90
  91         while (--ppos >= 0) {
  92                 if (EXT_LAST_INDEX(path[ppos].p_hdr) >
  93                     path[ppos].p_idx) {
  94                         int cur_ppos = ppos;
  95
  96                         /* index block */
  97                         path[ppos].p_idx++;
  98                         path[ppos].p_block = idx_pblock(path[ppos].p_idx);
  99                         if (path[ppos+1].p_bh)
 100                                 brelse(path[ppos+1].p_bh);
 101                         path[ppos+1].p_bh =
 102                                 sb_bread(inode->i_sb, path[ppos].p_block);
 103                         if (!path[ppos+1].p_bh)
 104                                 return -EIO;
 105                         path[ppos+1].p_hdr =
 106                                 ext_block_hdr(path[ppos+1].p_bh);
 107
 108                         /* Halfway index block */
 109                         while (++cur_ppos < leaf_ppos) {
 110                                 path[cur_ppos].p_idx =
 111                                         EXT_FIRST_INDEX(path[cur_ppos].p_hdr);
 112                                 path[cur_ppos].p_block =
 113                                         idx_pblock(path[cur_ppos].p_idx);
 114                                 if (path[cur_ppos+1].p_bh)
 115                                         brelse(path[cur_ppos+1].p_bh);
 116                                 path[cur_ppos+1].p_bh = sb_bread(inode->i_sb,
 117                                         path[cur_ppos].p_block);
 118                                 if (!path[cur_ppos+1].p_bh)
 119                                         return -EIO;
 120                                 path[cur_ppos+1].p_hdr =
 121                                         ext_block_hdr(path[cur_ppos+1].p_bh);
 122                         }
 123
 124                         path[leaf_ppos].p_ext = *extent = NULL;
 125
 126                         eh = path[leaf_ppos].p_hdr;
 127                         if (le16_to_cpu(eh->eh_entries) == 0)
 128                                 /* empty leaf is found */
 129                                 return -ENODATA;
 130
 131                         /* leaf block */
 132                         path[leaf_ppos].p_ext = *extent =
 133                                 EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr);
 134                         path[leaf_ppos].p_block =
 135                                         ext_pblock(path[leaf_ppos].p_ext);
 136                         return 0;
 137                 }
 138         }
 139         /* We found the last extent */
 140         return 1;
 141 }
 142
 143 /**
 144  * mext_check_null_inode - NULL check for two inodes
 145  *
 146  * If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
 147  */
 148 static int
 149 mext_check_null_inode(struct inode *inode1, struct inode *inode2,
 150                 const char *function)
 151 {
 152         int ret = 0;
 153
 154         if (inode1 == NULL) {
 155                 __ext4_error(inode2->i_sb, function,
 156                         "Both inodes should not be NULL: "
 157                         "inode1 NULL inode2 %lu", inode2->i_ino);
 158                 ret = -EIO;
 159         } else if (inode2 == NULL) {
 160                 __ext4_error(inode1->i_sb, function,
 161                         "Both inodes should not be NULL: "
 162                         "inode1 %lu inode2 NULL", inode1->i_ino);
 163                 ret = -EIO;
 164         }
 165         return ret;
 166 }
 167
 168 /**
 169  * double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
 170  *
 171  * @orig_inode:         original inode structure
 172  * @donor_inode:        donor inode structure
 173  * Acquire write lock of i_data_sem of the two inodes (orig and donor) by
 174  * i_ino order.
 175  */
 176 static void
 177 double_down_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
 178 {
 179         struct inode *first = orig_inode, *second = donor_inode;
 180
 181         /*
 182          * Use the inode number to provide the stable locking order instead
 183          * of its address, because the C language doesn't guarantee you can
 184          * compare pointers that don't come from the same array.
 185          */
 186         if (donor_inode->i_ino < orig_inode->i_ino) {
 187                 first = donor_inode;
 188                 second = orig_inode;
 189         }
 190
 191         down_write(&EXT4_I(first)->i_data_sem);
 192         down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
 193 }
 194
 195 /**
 196  * double_up_write_data_sem - Release two inodes' write lock of i_data_sem
 197  *
 198  * @orig_inode:         original inode structure to be released its lock first
 199  * @donor_inode:        donor inode structure to be released its lock second
 200  * Release write lock of i_data_sem of two inodes (orig and donor).
 201  */
 202 static void
 203 double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
 204 {
 205         up_write(&EXT4_I(orig_inode)->i_data_sem);
 206         up_write(&EXT4_I(donor_inode)->i_data_sem);
 207 }
 208
 209 /**
 210  * mext_insert_across_blocks - Insert extents across leaf block
 211  *
 212  * @handle:             journal handle
 213  * @orig_inode:         original inode
 214  * @o_start:            first original extent to be changed
 215  * @o_end:              last original extent to be changed
 216  * @start_ext:          first new extent to be inserted
 217  * @new_ext:            middle of new extent to be inserted
 218  * @end_ext:            last new extent to be inserted
 219  *
 220  * Allocate a new leaf block and insert extents into it. Return 0 on success,
 221  * or a negative error value on failure.
 222  */
 223 static int
 224 mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
 225                 struct ext4_extent *o_start, struct ext4_extent *o_end,
 226                 struct ext4_extent *start_ext, struct ext4_extent *new_ext,
 227                 struct ext4_extent *end_ext)
 228 {
 229         struct ext4_ext_path *orig_path = NULL;
 230         ext4_lblk_t eblock = 0;
 231         int new_flag = 0;
 232         int end_flag = 0;
 233         int err = 0;
 234
 235         if (start_ext->ee_len && new_ext->ee_len && end_ext->ee_len) {
 236                 if (o_start == o_end) {
 237
 238                         /*       start_ext   new_ext    end_ext
 239                          * donor |---------|-----------|--------|
 240                          * orig  |------------------------------|
 241                          */
 242                         end_flag = 1;
 243                 } else {
 244
 245                         /*       start_ext   new_ext   end_ext
 246                          * donor |---------|----------|---------|
 247                          * orig  |---------------|--------------|
 248                          */
 249                         o_end->ee_block = end_ext->ee_block;
 250                         o_end->ee_len = end_ext->ee_len;
 251                         ext4_ext_store_pblock(o_end, ext_pblock(end_ext));
 252                 }
 253
 254                 o_start->ee_len = start_ext->ee_len;
 255                 eblock = le32_to_cpu(start_ext->ee_block);
 256                 new_flag = 1;
 257
 258         } else if (start_ext->ee_len && new_ext->ee_len &&
 259                    !end_ext->ee_len && o_start == o_end) {
 260
 261                 /*       start_ext      new_ext
 262                  * donor |--------------|---------------|
 263                  * orig  |------------------------------|
 264                  */
 265                 o_start->ee_len = start_ext->ee_len;
 266                 eblock = le32_to_cpu(start_ext->ee_block);
 267                 new_flag = 1;
 268
 269         } else if (!start_ext->ee_len && new_ext->ee_len &&
 270                    end_ext->ee_len && o_start == o_end) {
 271
 272                 /*        new_ext       end_ext
 273                  * donor |--------------|---------------|
 274                  * orig  |------------------------------|
 275                  */
 276                 o_end->ee_block = end_ext->ee_block;
 277                 o_end->ee_len = end_ext->ee_len;
 278                 ext4_ext_store_pblock(o_end, ext_pblock(end_ext));
 279
 280                 /*
 281                  * Set 0 to the extent block if new_ext was
 282                  * the first block.
 283                  */
 284                 if (new_ext->ee_block)
 285                         eblock = le32_to_cpu(new_ext->ee_block);
 286
 287                 new_flag = 1;
 288         } else {
 289                 ext4_debug("ext4 move extent: Unexpected insert case\n");
 290                 return -EIO;
 291         }
 292
 293         if (new_flag) {
 294                 err = get_ext_path(orig_inode, eblock, &orig_path);
 295                 if (err)
 296                         goto out;
 297
 298                 if (ext4_ext_insert_extent(handle, orig_inode,
 299                                         orig_path, new_ext, 0))
 300                         goto out;
 301         }
 302
 303         if (end_flag) {
 304                 err = get_ext_path(orig_inode,
 305                                 le32_to_cpu(end_ext->ee_block) - 1, &orig_path);
 306                 if (err)
 307                         goto out;
 308
 309                 if (ext4_ext_insert_extent(handle, orig_inode,
 310                                            orig_path, end_ext, 0))
 311                         goto out;
 312         }
 313 out:
 314         if (orig_path) {
 315                 ext4_ext_drop_refs(orig_path);
 316                 kfree(orig_path);
 317         }
 318
 319         return err;
 320
 321 }
 322
 323 /**
 324  * mext_insert_inside_block - Insert new extent to the extent block
 325  *
 326  * @o_start:            first original extent to be moved
 327  * @o_end:              last original extent to be moved
 328  * @start_ext:          first new extent to be inserted
 329  * @new_ext:            middle of new extent to be inserted
 330  * @end_ext:            last new extent to be inserted
 331  * @eh:                 extent header of target leaf block
 332  * @range_to_move:      used to decide how to insert extent
 333  *
 334  * Insert extents into the leaf block. The extent (@o_start) is overwritten
 335  * by inserted extents.
 336  */
 337 static void
 338 mext_insert_inside_block(struct ext4_extent *o_start,
 339                               struct ext4_extent *o_end,
 340                               struct ext4_extent *start_ext,
 341                               struct ext4_extent *new_ext,
 342                               struct ext4_extent *end_ext,
 343                               struct ext4_extent_header *eh,
 344                               int range_to_move)
 345 {
 346         int i = 0;
 347         unsigned long len;
 348
 349         /* Move the existing extents */
 350         if (range_to_move && o_end < EXT_LAST_EXTENT(eh)) {
 351                 len = (unsigned long)(EXT_LAST_EXTENT(eh) + 1) -
 352                         (unsigned long)(o_end + 1);
 353                 memmove(o_end + 1 + range_to_move, o_end + 1, len);
 354         }
 355
 356         /* Insert start entry */
 357         if (start_ext->ee_len)
 358                 o_start[i++].ee_len = start_ext->ee_len;
 359
 360         /* Insert new entry */
 361         if (new_ext->ee_len) {
 362                 o_start[i] = *new_ext;
 363                 ext4_ext_store_pblock(&o_start[i++], ext_pblock(new_ext));
 364         }
 365
 366         /* Insert end entry */
 367         if (end_ext->ee_len)
 368                 o_start[i] = *end_ext;
 369
 370         /* Increment the total entries counter on the extent block */
 371         le16_add_cpu(&eh->eh_entries, range_to_move);
 372 }
 373
 374 /**
 375  * mext_insert_extents - Insert new extent
 376  *
 377  * @handle:     journal handle
 378  * @orig_inode: original inode
 379  * @orig_path:  path indicates first extent to be changed
 380  * @o_start:    first original extent to be changed
 381  * @o_end:      last original extent to be changed
 382  * @start_ext:  first new extent to be inserted
 383  * @new_ext:    middle of new extent to be inserted
 384  * @end_ext:    last new extent to be inserted
 385  *
 386  * Call the function to insert extents. If we cannot add more extents into
 387  * the leaf block, we call mext_insert_across_blocks() to create a
 388  * new leaf block. Otherwise call mext_insert_inside_block(). Return 0
 389  * on success, or a negative error value on failure.
 390  */
 391 static int
 392 mext_insert_extents(handle_t *handle, struct inode *orig_inode,
 393                          struct ext4_ext_path *orig_path,
 394                          struct ext4_extent *o_start,
 395                          struct ext4_extent *o_end,
 396                          struct ext4_extent *start_ext,
 397                          struct ext4_extent *new_ext,
 398                          struct ext4_extent *end_ext)
 399 {
 400         struct  ext4_extent_header *eh;
 401         unsigned long need_slots, slots_range;
 402         int     range_to_move, depth, ret;
 403
 404         /*
 405          * The extents need to be inserted
 406          * start_extent + new_extent + end_extent.
 407          */
 408         need_slots = (start_ext->ee_len ? 1 : 0) + (end_ext->ee_len ? 1 : 0) +
 409                 (new_ext->ee_len ? 1 : 0);
 410
 411         /* The number of slots between start and end */
 412         slots_range = ((unsigned long)(o_end + 1) - (unsigned long)o_start + 1)
 413                 / sizeof(struct ext4_extent);
 414
 415         /* Range to move the end of extent */
 416         range_to_move = need_slots - slots_range;
 417         depth = orig_path->p_depth;
 418         orig_path += depth;
 419         eh = orig_path->p_hdr;
 420
 421         if (depth) {
 422                 /* Register to journal */
 423                 ret = ext4_journal_get_write_access(handle, orig_path->p_bh);
 424                 if (ret)
 425                         return ret;
 426         }
 427
 428         /* Expansion */
 429         if (range_to_move > 0 &&
 430                 (range_to_move > le16_to_cpu(eh->eh_max)
 431                         - le16_to_cpu(eh->eh_entries))) {
 432
 433                 ret = mext_insert_across_blocks(handle, orig_inode, o_start,
 434                                         o_end, start_ext, new_ext, end_ext);
 435                 if (ret < 0)
 436                         return ret;
 437         } else
 438                 mext_insert_inside_block(o_start, o_end, start_ext, new_ext,
 439                                                 end_ext, eh, range_to_move);
 440
 441         if (depth) {
 442                 ret = ext4_handle_dirty_metadata(handle, orig_inode,
 443                                                  orig_path->p_bh);
 444                 if (ret)
 445                         return ret;
 446         } else {
 447                 ret = ext4_mark_inode_dirty(handle, orig_inode);
 448                 if (ret < 0)
 449                         return ret;
 450         }
 451
 452         return 0;
 453 }
 454
 455 /**
 456  * mext_leaf_block - Move one leaf extent block into the inode.
 457  *
 458  * @handle:             journal handle
 459  * @orig_inode:         original inode
 460  * @orig_path:          path indicates first extent to be changed
 461  * @dext:               donor extent
 462  * @from:               start offset on the target file
 463  *
 464  * In order to insert extents into the leaf block, we must divide the extent
 465  * in the leaf block into three extents. The one is located to be inserted
 466  * extents, and the others are located around it.
 467  *
 468  * Therefore, this function creates structures to save extents of the leaf
 469  * block, and inserts extents by calling mext_insert_extents() with
 470  * created extents. Return 0 on success, or a negative error value on failure.
 471  */
 472 static int
 473 mext_leaf_block(handle_t *handle, struct inode *orig_inode,
 474                      struct ext4_ext_path *orig_path, struct ext4_extent *dext,
 475                      ext4_lblk_t *from)
 476 {
 477         struct ext4_extent *oext, *o_start, *o_end, *prev_ext;
 478         struct ext4_extent new_ext, start_ext, end_ext;
 479         ext4_lblk_t new_ext_end;
 480         int oext_alen, new_ext_alen, end_ext_alen;
 481         int depth = ext_depth(orig_inode);
 482         int ret;
 483
 484         o_start = o_end = oext = orig_path[depth].p_ext;
 485         oext_alen = ext4_ext_get_actual_len(oext);
 486         start_ext.ee_len = end_ext.ee_len = 0;
 487
 488         new_ext.ee_block = cpu_to_le32(*from);
 489         ext4_ext_store_pblock(&new_ext, ext_pblock(dext));
 490         new_ext.ee_len = dext->ee_len;
 491         new_ext_alen = ext4_ext_get_actual_len(&new_ext);
 492         new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
 493
 494         /*
 495          * Case: original extent is first
 496          * oext      |--------|
 497          * new_ext      |--|
 498          * start_ext |--|
 499          */
 500         if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) &&
 501                 le32_to_cpu(new_ext.ee_block) <
 502                 le32_to_cpu(oext->ee_block) + oext_alen) {
 503                 start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
 504                                                le32_to_cpu(oext->ee_block));
 505                 start_ext.ee_block = oext->ee_block;
 506                 copy_extent_status(oext, &start_ext);
 507         } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
 508                 prev_ext = oext - 1;
 509                 /*
 510                  * We can merge new_ext into previous extent,
 511                  * if these are contiguous and same extent type.
 512                  */
 513                 if (ext4_can_extents_be_merged(orig_inode, prev_ext,
 514                                                &new_ext)) {
 515                         o_start = prev_ext;
 516                         start_ext.ee_len = cpu_to_le16(
 517                                 ext4_ext_get_actual_len(prev_ext) +
 518                                 new_ext_alen);
 519                         start_ext.ee_block = oext->ee_block;
 520                         copy_extent_status(prev_ext, &start_ext);
 521                         new_ext.ee_len = 0;
 522                 }
 523         }
 524
 525         /*
 526          * Case: new_ext_end must be less than oext
 527          * oext      |-----------|
 528          * new_ext       |-------|
 529          */
 530         if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) {
 531                 ext4_error(orig_inode->i_sb,
 532                         "new_ext_end(%u) should be less than or equal to "
 533                         "oext->ee_block(%u) + oext_alen(%d) - 1",
 534                         new_ext_end, le32_to_cpu(oext->ee_block),
 535                         oext_alen);
 536                 ret = -EIO;
 537                 goto out;
 538         }
 539
 540         /*
 541          * Case: new_ext is smaller than original extent
 542          * oext    |---------------|
 543          * new_ext |-----------|
 544          * end_ext             |---|
 545          */
 546         if (le32_to_cpu(oext->ee_block) <= new_ext_end &&
 547                 new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) {
 548                 end_ext.ee_len =
 549                         cpu_to_le16(le32_to_cpu(oext->ee_block) +
 550                         oext_alen - 1 - new_ext_end);
 551                 copy_extent_status(oext, &end_ext);
 552                 end_ext_alen = ext4_ext_get_actual_len(&end_ext);
 553                 ext4_ext_store_pblock(&end_ext,
 554                         (ext_pblock(o_end) + oext_alen - end_ext_alen));
 555                 end_ext.ee_block =
 556                         cpu_to_le32(le32_to_cpu(o_end->ee_block) +
 557                         oext_alen - end_ext_alen);
 558         }
 559
 560         ret = mext_insert_extents(handle, orig_inode, orig_path, o_start,
 561                                 o_end, &start_ext, &new_ext, &end_ext);
 562 out:
 563         return ret;
 564 }
 565
 566 /**
 567  * mext_calc_swap_extents - Calculate extents for extent swapping.
 568  *
 569  * @tmp_dext:           the extent that will belong to the original inode
 570  * @tmp_oext:           the extent that will belong to the donor inode
 571  * @orig_off:           block offset of original inode
 572  * @donor_off:          block offset of donor inode
 573  * @max_count:          the maximum length of extents
 574  *
 575  * Return 0 on success, or a negative error value on failure.
 576  */
 577 static int
 578 mext_calc_swap_extents(struct ext4_extent *tmp_dext,
 579                               struct ext4_extent *tmp_oext,
 580                               ext4_lblk_t orig_off, ext4_lblk_t donor_off,
 581                               ext4_lblk_t max_count)
 582 {
 583         ext4_lblk_t diff, orig_diff;
 584         struct ext4_extent dext_old, oext_old;
 585
 586         BUG_ON(orig_off != donor_off);
 587
 588         /* original and donor extents have to cover the same block offset */
 589         if (orig_off < le32_to_cpu(tmp_oext->ee_block) ||
 590             le32_to_cpu(tmp_oext->ee_block) +
 591                         ext4_ext_get_actual_len(tmp_oext) - 1 < orig_off)
 592                 return -ENODATA;
 593
 594         if (orig_off < le32_to_cpu(tmp_dext->ee_block) ||
 595             le32_to_cpu(tmp_dext->ee_block) +
 596                         ext4_ext_get_actual_len(tmp_dext) - 1 < orig_off)
 597                 return -ENODATA;
 598
 599         dext_old = *tmp_dext;
 600         oext_old = *tmp_oext;
 601
 602         /* When tmp_dext is too large, pick up the target range. */
 603         diff = donor_off - le32_to_cpu(tmp_dext->ee_block);
 604
 605         ext4_ext_store_pblock(tmp_dext, ext_pblock(tmp_dext) + diff);
 606         tmp_dext->ee_block =
 607                         cpu_to_le32(le32_to_cpu(tmp_dext->ee_block) + diff);
 608         tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_dext->ee_len) - diff);
 609
 610         if (max_count < ext4_ext_get_actual_len(tmp_dext))
 611                 tmp_dext->ee_len = cpu_to_le16(max_count);
 612
 613         orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block);
 614         ext4_ext_store_pblock(tmp_oext, ext_pblock(tmp_oext) + orig_diff);
 615
 616         /* Adjust extent length if donor extent is larger than orig */
 617         if (ext4_ext_get_actual_len(tmp_dext) >
 618             ext4_ext_get_actual_len(tmp_oext) - orig_diff)
 619                 tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) -
 620                                                 orig_diff);
 621
 622         tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext));
 623
 624         copy_extent_status(&oext_old, tmp_dext);
 625         copy_extent_status(&dext_old, tmp_oext);
 626
 627         return 0;
 628 }
 629
 630 /**
 631  * mext_replace_branches - Replace original extents with new extents
 632  *
 633  * @handle:             journal handle
 634  * @orig_inode:         original inode
 635  * @donor_inode:        donor inode
 636  * @from:               block offset of orig_inode
 637  * @count:              block count to be replaced
 638  * @err:                pointer to save return value
 639  *
 640  * Replace original inode extents and donor inode extents page by page.
 641  * We implement this replacement in the following three steps:
 642  * 1. Save the block information of original and donor inodes into
 643  *    dummy extents.
 644  * 2. Change the block information of original inode to point at the
 645  *    donor inode blocks.
 646  * 3. Change the block information of donor inode to point at the saved
 647  *    original inode blocks in the dummy extents.
 648  *
 649  * Return replaced block count.
 650  */
 651 static int
 652 mext_replace_branches(handle_t *handle, struct inode *orig_inode,
 653                            struct inode *donor_inode, ext4_lblk_t from,
 654                            ext4_lblk_t count, int *err)
 655 {
 656         struct ext4_ext_path *orig_path = NULL;
 657         struct ext4_ext_path *donor_path = NULL;
 658         struct ext4_extent *oext, *dext;
 659         struct ext4_extent tmp_dext, tmp_oext;
 660         ext4_lblk_t orig_off = from, donor_off = from;
 661         int depth;
 662         int replaced_count = 0;
 663         int dext_alen;
 664
 665         /* Protect extent trees against block allocations via delalloc */
 666         double_down_write_data_sem(orig_inode, donor_inode);
 667
 668         /* Get the original extent for the block "orig_off" */
 669         *err = get_ext_path(orig_inode, orig_off, &orig_path);
 670         if (*err)
 671                 goto out;
 672
 673         /* Get the donor extent for the head */
 674         *err = get_ext_path(donor_inode, donor_off, &donor_path);
 675         if (*err)
 676                 goto out;
 677         depth = ext_depth(orig_inode);
 678         oext = orig_path[depth].p_ext;
 679         tmp_oext = *oext;
 680
 681         depth = ext_depth(donor_inode);
 682         dext = donor_path[depth].p_ext;
 683         tmp_dext = *dext;
 684
 685         *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
 686                                       donor_off, count);
 687         if (*err)
 688                 goto out;
 689
 690         /* Loop for the donor extents */
 691         while (1) {
 692                 /* The extent for donor must be found. */
 693                 if (!dext) {
 694                         ext4_error(donor_inode->i_sb,
 695                                    "The extent for donor must be found");
 696                         *err = -EIO;
 697                         goto out;
 698                 } else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) {
 699                         ext4_error(donor_inode->i_sb,
 700                                 "Donor offset(%u) and the first block of donor "
 701                                 "extent(%u) should be equal",
 702                                 donor_off,
 703                                 le32_to_cpu(tmp_dext.ee_block));
 704                         *err = -EIO;
 705                         goto out;
 706                 }
 707
 708                 /* Set donor extent to orig extent */
 709                 *err = mext_leaf_block(handle, orig_inode,
 710                                            orig_path, &tmp_dext, &orig_off);
 711                 if (*err)
 712                         goto out;
 713
 714                 /* Set orig extent to donor extent */
 715                 *err = mext_leaf_block(handle, donor_inode,
 716                                            donor_path, &tmp_oext, &donor_off);
 717                 if (*err)
 718                         goto out;
 719
 720                 dext_alen = ext4_ext_get_actual_len(&tmp_dext);
 721                 replaced_count += dext_alen;
 722                 donor_off += dext_alen;
 723                 orig_off += dext_alen;
 724
 725                 /* Already moved the expected blocks */
 726                 if (replaced_count >= count)
 727                         break;
 728
 729                 if (orig_path)
 730                         ext4_ext_drop_refs(orig_path);
 731                 *err = get_ext_path(orig_inode, orig_off, &orig_path);
 732                 if (*err)
 733                         goto out;
 734                 depth = ext_depth(orig_inode);
 735                 oext = orig_path[depth].p_ext;
 736                 tmp_oext = *oext;
 737
 738                 if (donor_path)
 739                         ext4_ext_drop_refs(donor_path);
 740                 *err = get_ext_path(donor_inode, donor_off, &donor_path);
 741                 if (*err)
 742                         goto out;
 743                 depth = ext_depth(donor_inode);
 744                 dext = donor_path[depth].p_ext;
 745                 tmp_dext = *dext;
 746
 747                 *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
 748                                            donor_off, count - replaced_count);
 749                 if (*err)
 750                         goto out;
 751         }
 752
 753 out:
 754         if (orig_path) {
 755                 ext4_ext_drop_refs(orig_path);
 756                 kfree(orig_path);
 757         }
 758         if (donor_path) {
 759                 ext4_ext_drop_refs(donor_path);
 760                 kfree(donor_path);
 761         }
 762
 763         ext4_ext_invalidate_cache(orig_inode);
 764         ext4_ext_invalidate_cache(donor_inode);
 765
 766         double_up_write_data_sem(orig_inode, donor_inode);
 767
 768         return replaced_count;
 769 }
 770
 771 /**
 772  * move_extent_per_page - Move extent data per page
 773  *
 774  * @o_filp:                     file structure of original file
 775  * @donor_inode:                donor inode
 776  * @orig_page_offset:           page index on original file
 777  * @data_offset_in_page:        block index where data swapping starts
 778  * @block_len_in_page:          the number of blocks to be swapped
 779  * @uninit:                     orig extent is uninitialized or not
 780  * @err:                        pointer to save return value
 781  *
 782  * Save the data in original inode blocks and replace original inode extents
 783  * with donor inode extents by calling mext_replace_branches().
 784  * Finally, write out the saved data in new original inode blocks. Return
 785  * replaced block count.
 786  */
 787 static int
 788 move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
 789                   pgoff_t orig_page_offset, int data_offset_in_page,
 790                   int block_len_in_page, int uninit, int *err)
 791 {
 792         struct inode *orig_inode = o_filp->f_dentry->d_inode;
 793         struct address_space *mapping = orig_inode->i_mapping;
 794         struct buffer_head *bh;
 795         struct page *page = NULL;
 796         const struct address_space_operations *a_ops = mapping->a_ops;
 797         handle_t *handle;
 798         ext4_lblk_t orig_blk_offset;
 799         long long offs = orig_page_offset << PAGE_CACHE_SHIFT;
 800         unsigned long blocksize = orig_inode->i_sb->s_blocksize;
 801         unsigned int w_flags = 0;
 802         unsigned int tmp_data_size, data_size, replaced_size;
 803         void *fsdata;
 804         int i, jblocks;
 805         int err2 = 0;
 806         int replaced_count = 0;
 807         int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
 808
 809         /*
 810          * It needs twice the amount of ordinary journal buffers because
 811          * inode and donor_inode may change each different metadata blocks.
 812          */
 813         jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
 814         handle = ext4_journal_start(orig_inode, jblocks);
 815         if (IS_ERR(handle)) {
 816                 *err = PTR_ERR(handle);
 817                 return 0;
 818         }
 819
 820         if (segment_eq(get_fs(), KERNEL_DS))
 821                 w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
 822
 823         orig_blk_offset = orig_page_offset * blocks_per_page +
 824                 data_offset_in_page;
 825
 826         /*
 827          * If orig extent is uninitialized one,
 828          * it's not necessary force the page into memory
 829          * and then force it to be written out again.
 830          * Just swap data blocks between orig and donor.
 831          */
 832         if (uninit) {
 833                 replaced_count = mext_replace_branches(handle, orig_inode,
 834                                                 donor_inode, orig_blk_offset,
 835                                                 block_len_in_page, err);
 836                 goto out2;
 837         }
 838
 839         offs = (long long)orig_blk_offset << orig_inode->i_blkbits;
 840
 841         /* Calculate data_size */
 842         if ((orig_blk_offset + block_len_in_page - 1) ==
 843             ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
 844                 /* Replace the last block */
 845                 tmp_data_size = orig_inode->i_size & (blocksize - 1);
 846                 /*
 847                  * If data_size equal zero, it shows data_size is multiples of
 848                  * blocksize. So we set appropriate value.
 849                  */
 850                 if (tmp_data_size == 0)
 851                         tmp_data_size = blocksize;
 852
 853                 data_size = tmp_data_size +
 854                         ((block_len_in_page - 1) << orig_inode->i_blkbits);
 855         } else
 856                 data_size = block_len_in_page << orig_inode->i_blkbits;
 857
 858         replaced_size = data_size;
 859
 860         *err = a_ops->write_begin(o_filp, mapping, offs, data_size, w_flags,
 861                                  &page, &fsdata);
 862         if (unlikely(*err < 0))
 863                 goto out;
 864
 865         if (!PageUptodate(page)) {
 866                 mapping->a_ops->readpage(o_filp, page);
 867                 lock_page(page);
 868         }
 869
 870         /*
 871          * try_to_release_page() doesn't call releasepage in writeback mode.
 872          * We should care about the order of writing to the same file
 873          * by multiple move extent processes.
 874          * It needs to call wait_on_page_writeback() to wait for the
 875          * writeback of the page.
 876          */
 877         if (PageWriteback(page))
 878                 wait_on_page_writeback(page);
 879
 880         /* Release old bh and drop refs */
 881         try_to_release_page(page, 0);
 882
 883         replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
 884                                         orig_blk_offset, block_len_in_page,
 885                                         &err2);
 886         if (err2) {
 887                 if (replaced_count) {
 888                         block_len_in_page = replaced_count;
 889                         replaced_size =
 890                                 block_len_in_page << orig_inode->i_blkbits;
 891                 } else
 892                         goto out;
 893         }
 894
 895         if (!page_has_buffers(page))
 896                 create_empty_buffers(page, 1 << orig_inode->i_blkbits, 0);
 897
 898         bh = page_buffers(page);
 899         for (i = 0; i < data_offset_in_page; i++)
 900                 bh = bh->b_this_page;
 901
 902         for (i = 0; i < block_len_in_page; i++) {
 903                 *err = ext4_get_block(orig_inode,
 904                                 (sector_t)(orig_blk_offset + i), bh, 0);
 905                 if (*err < 0)
 906                         goto out;
 907
 908                 if (bh->b_this_page != NULL)
 909                         bh = bh->b_this_page;
 910         }
 911
 912         *err = a_ops->write_end(o_filp, mapping, offs, data_size, replaced_size,
 913                                page, fsdata);
 914         page = NULL;
 915
 916 out:
 917         if (unlikely(page)) {
 918                 if (PageLocked(page))
 919                         unlock_page(page);
 920                 page_cache_release(page);
 921                 ext4_journal_stop(handle);
 922         }
 923 out2:
 924         ext4_journal_stop(handle);
 925
 926         if (err2)
 927                 *err = err2;
 928
 929         return replaced_count;
 930 }
 931
 932 /**
 933  * mext_check_arguments - Check whether move extent can be done
 934  *
 935  * @orig_inode:         original inode
 936  * @donor_inode:        donor inode
 937  * @orig_start:         logical start offset in block for orig
 938  * @donor_start:        logical start offset in block for donor
 939  * @len:                the number of blocks to be moved
 940  *
 941  * Check the arguments of ext4_move_extents() whether the files can be
 942  * exchanged with each other.
 943  * Return 0 on success, or a negative error value on failure.
 944  */
 945 static int
 946 mext_check_arguments(struct inode *orig_inode,
 947                      struct inode *donor_inode, __u64 orig_start,
 948                      __u64 donor_start, __u64 *len)
 949 {
 950         ext4_lblk_t orig_blocks, donor_blocks;
 951         unsigned int blkbits = orig_inode->i_blkbits;
 952         unsigned int blocksize = 1 << blkbits;
 953
 954         if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
 955                 ext4_debug("ext4 move extent: suid or sgid is set"
 956                            " to donor file [ino:orig %lu, donor %lu]\n",
 957                            orig_inode->i_ino, donor_inode->i_ino);
 958                 return -EINVAL;
 959         }
 960
 961         /* Ext4 move extent does not support swapfile */
 962         if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
 963                 ext4_debug("ext4 move extent: The argument files should "
 964                         "not be swapfile [ino:orig %lu, donor %lu]\n",
 965                         orig_inode->i_ino, donor_inode->i_ino);
 966                 return -EINVAL;
 967         }
 968
 969         /* Files should be in the same ext4 FS */
 970         if (orig_inode->i_sb != donor_inode->i_sb) {
 971                 ext4_debug("ext4 move extent: The argument files "
 972                         "should be in same FS [ino:orig %lu, donor %lu]\n",
 973                         orig_inode->i_ino, donor_inode->i_ino);
 974                 return -EINVAL;
 975         }
 976
 977         /* Ext4 move extent supports only extent based file */
 978         if (!(EXT4_I(orig_inode)->i_flags & EXT4_EXTENTS_FL)) {
 979                 ext4_debug("ext4 move extent: orig file is not extents "
 980                         "based file [ino:orig %lu]\n", orig_inode->i_ino);
 981                 return -EOPNOTSUPP;
 982         } else if (!(EXT4_I(donor_inode)->i_flags & EXT4_EXTENTS_FL)) {
 983                 ext4_debug("ext4 move extent: donor file is not extents "
 984                         "based file [ino:donor %lu]\n", donor_inode->i_ino);
 985                 return -EOPNOTSUPP;
 986         }
 987
 988         if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
 989                 ext4_debug("ext4 move extent: File size is 0 byte\n");
 990                 return -EINVAL;
 991         }
 992
 993         /* Start offset should be same */
 994         if (orig_start != donor_start) {
 995                 ext4_debug("ext4 move extent: orig and donor's start "
 996                         "offset are not same [ino:orig %lu, donor %lu]\n",
 997                         orig_inode->i_ino, donor_inode->i_ino);
 998                 return -EINVAL;
 999         }
1000
1001         if ((orig_start > EXT_MAX_BLOCK) ||
1002             (donor_start > EXT_MAX_BLOCK) ||
1003             (*len > EXT_MAX_BLOCK) ||
1004             (orig_start + *len > EXT_MAX_BLOCK))  {
1005                 ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
1006                         "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCK,
1007                         orig_inode->i_ino, donor_inode->i_ino);
1008                 return -EINVAL;
1009         }
1010
1011         if (orig_inode->i_size > donor_inode->i_size) {
1012                 donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits;
1013                 /* TODO: eliminate this artificial restriction */
1014                 if (orig_start >= donor_blocks) {
1015                         ext4_debug("ext4 move extent: orig start offset "
1016                         "[%llu] should be less than donor file blocks "
1017                         "[%u] [ino:orig %lu, donor %lu]\n",
1018                         orig_start, donor_blocks,
1019                         orig_inode->i_ino, donor_inode->i_ino);
1020                         return -EINVAL;
1021                 }
1022
1023                 /* TODO: eliminate this artificial restriction */
1024                 if (orig_start + *len > donor_blocks) {
1025                         ext4_debug("ext4 move extent: End offset [%llu] should "
1026                                 "be less than donor file blocks [%u]."
1027                                 "So adjust length from %llu to %llu "
1028                                 "[ino:orig %lu, donor %lu]\n",
1029                                 orig_start + *len, donor_blocks,
1030                                 *len, donor_blocks - orig_start,
1031                                 orig_inode->i_ino, donor_inode->i_ino);
1032                         *len = donor_blocks - orig_start;
1033                 }
1034         } else {
1035                 orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits;
1036                 if (orig_start >= orig_blocks) {
1037                         ext4_debug("ext4 move extent: start offset [%llu] "
1038                                 "should be less than original file blocks "
1039                                 "[%u] [ino:orig %lu, donor %lu]\n",
1040                                  orig_start, orig_blocks,
1041                                 orig_inode->i_ino, donor_inode->i_ino);
1042                         return -EINVAL;
1043                 }
1044
1045                 if (orig_start + *len > orig_blocks) {
1046                         ext4_debug("ext4 move extent: Adjust length "
1047                                 "from %llu to %llu. Because it should be "
1048                                 "less than original file blocks "
1049                                 "[ino:orig %lu, donor %lu]\n",
1050                                 *len, orig_blocks - orig_start,
1051                                 orig_inode->i_ino, donor_inode->i_ino);
1052                         *len = orig_blocks - orig_start;
1053                 }
1054         }
1055
1056         if (!*len) {
1057                 ext4_debug("ext4 move extent: len should not be 0 "
1058                         "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
1059                         donor_inode->i_ino);
1060                 return -EINVAL;
1061         }
1062
1063         return 0;
1064 }
1065
1066 /**
1067  * mext_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
1068  *
1069  * @inode1:     the inode structure
1070  * @inode2:     the inode structure
1071  *
1072  * Lock two inodes' i_mutex by i_ino order.
1073  * If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
1074  */
1075 static int
1076 mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
1077 {
1078         int ret = 0;
1079
1080         BUG_ON(inode1 == NULL && inode2 == NULL);
1081
1082         ret = mext_check_null_inode(inode1, inode2, __func__);
1083         if (ret < 0)
1084                 goto out;
1085
1086         if (inode1 == inode2) {
1087                 mutex_lock(&inode1->i_mutex);
1088                 goto out;
1089         }
1090
1091         if (inode1->i_ino < inode2->i_ino) {
1092                 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1093                 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1094         } else {
1095                 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1096                 mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1097         }
1098
1099 out:
1100         return ret;
1101 }
1102
1103 /**
1104  * mext_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
1105  *
1106  * @inode1:     the inode that is released first
1107  * @inode2:     the inode that is released second
1108  *
1109  * If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
1110  */
1111
1112 static int
1113 mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
1114 {
1115         int ret = 0;
1116
1117         BUG_ON(inode1 == NULL && inode2 == NULL);
1118
1119         ret = mext_check_null_inode(inode1, inode2, __func__);
1120         if (ret < 0)
1121                 goto out;
1122
1123         if (inode1)
1124                 mutex_unlock(&inode1->i_mutex);
1125
1126         if (inode2 && inode2 != inode1)
1127                 mutex_unlock(&inode2->i_mutex);
1128
1129 out:
1130         return ret;
1131 }
1132
1133 /**
1134  * ext4_move_extents - Exchange the specified range of a file
1135  *
1136  * @o_filp:             file structure of the original file
1137  * @d_filp:             file structure of the donor file
1138  * @orig_start:         start offset in block for orig
1139  * @donor_start:        start offset in block for donor
1140  * @len:                the number of blocks to be moved
1141  * @moved_len:          moved block length
1142  *
1143  * This function returns 0 and moved block length is set in moved_len
1144  * if succeed, otherwise returns error value.
1145  *
1146  * Note: ext4_move_extents() proceeds the following order.
1147  * 1:ext4_move_extents() calculates the last block number of moving extent
1148  *   function by the start block number (orig_start) and the number of blocks
1149  *   to be moved (len) specified as arguments.
1150  *   If the {orig, donor}_start points a hole, the extent's start offset
1151  *   pointed by ext_cur (current extent), holecheck_path, orig_path are set
1152  *   after hole behind.
1153  * 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
1154  *   or the ext_cur exceeds the block_end which is last logical block number.
1155  * 3:To get the length of continues area, call mext_next_extent()
1156  *   specified with the ext_cur (initial value is holecheck_path) re-cursive,
1157  *   until find un-continuous extent, the start logical block number exceeds
1158  *   the block_end or the extent points to the last extent.
1159  * 4:Exchange the original inode data with donor inode data
1160  *   from orig_page_offset to seq_end_page.
1161  *   The start indexes of data are specified as arguments.
1162  *   That of the original inode is orig_page_offset,
1163  *   and the donor inode is also orig_page_offset
1164  *   (To easily handle blocksize != pagesize case, the offset for the
1165  *   donor inode is block unit).
1166  * 5:Update holecheck_path and orig_path to points a next proceeding extent,
1167  *   then returns to step 2.
1168  * 6:Release holecheck_path, orig_path and set the len to moved_len
1169  *   which shows the number of moved blocks.
1170  *   The moved_len is useful for the command to calculate the file offset
1171  *   for starting next move extent ioctl.
1172  * 7:Return 0 on success, or a negative error value on failure.
1173  */
1174 int
1175 ext4_move_extents(struct file *o_filp, struct file *d_filp,
1176                  __u64 orig_start, __u64 donor_start, __u64 len,
1177                  __u64 *moved_len)
1178 {
1179         struct inode *orig_inode = o_filp->f_dentry->d_inode;
1180         struct inode *donor_inode = d_filp->f_dentry->d_inode;
1181         struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL;
1182         struct ext4_extent *ext_prev, *ext_cur, *ext_dummy;
1183         ext4_lblk_t block_start = orig_start;
1184         ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
1185         ext4_lblk_t rest_blocks;
1186         pgoff_t orig_page_offset = 0, seq_end_page;
1187         int ret1, ret2, depth, last_extent = 0;
1188         int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
1189         int data_offset_in_page;
1190         int block_len_in_page;
1191         int uninit;
1192
1193         /* orig and donor should be different file */
1194         if (orig_inode->i_ino == donor_inode->i_ino) {
1195                 ext4_debug("ext4 move extent: The argument files should not "
1196                         "be same file [ino:orig %lu, donor %lu]\n",
1197                         orig_inode->i_ino, donor_inode->i_ino);
1198                 return -EINVAL;
1199         }
1200
1201         /* Regular file check */
1202         if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
1203                 ext4_debug("ext4 move extent: The argument files should be "
1204                         "regular file [ino:orig %lu, donor %lu]\n",
1205                         orig_inode->i_ino, donor_inode->i_ino);
1206                 return -EINVAL;
1207         }
1208
1209         /* Protect orig and donor inodes against a truncate */
1210         ret1 = mext_inode_double_lock(orig_inode, donor_inode);
1211         if (ret1 < 0)
1212                 return ret1;
1213
1214         /* Protect extent tree against block allocations via delalloc */
1215         double_down_write_data_sem(orig_inode, donor_inode);
1216         /* Check the filesystem environment whether move_extent can be done */
1217         ret1 = mext_check_arguments(orig_inode, donor_inode, orig_start,
1218                                     donor_start, &len);
1219         if (ret1)
1220                 goto out;
1221
1222         file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
1223         block_end = block_start + len - 1;
1224         if (file_end < block_end)
1225                 len -= block_end - file_end;
1226
1227         ret1 = get_ext_path(orig_inode, block_start, &orig_path);
1228         if (ret1)
1229                 goto out;
1230
1231         /* Get path structure to check the hole */
1232         ret1 = get_ext_path(orig_inode, block_start, &holecheck_path);
1233         if (ret1)
1234                 goto out;
1235
1236         depth = ext_depth(orig_inode);
1237         ext_cur = holecheck_path[depth].p_ext;
1238
1239         /*
1240          * Get proper starting location of block replacement if block_start was
1241          * within the hole.
1242          */
1243         if (le32_to_cpu(ext_cur->ee_block) +
1244                 ext4_ext_get_actual_len(ext_cur) - 1 < block_start) {
1245                 /*
1246                  * The hole exists between extents or the tail of
1247                  * original file.
1248                  */
1249                 last_extent = mext_next_extent(orig_inode,
1250                                         holecheck_path, &ext_cur);
1251                 if (last_extent < 0) {
1252                         ret1 = last_extent;
1253                         goto out;
1254                 }
1255                 last_extent = mext_next_extent(orig_inode, orig_path,
1256                                                         &ext_dummy);
1257                 if (last_extent < 0) {
1258                         ret1 = last_extent;
1259                         goto out;
1260                 }
1261                 seq_start = le32_to_cpu(ext_cur->ee_block);
1262         } else if (le32_to_cpu(ext_cur->ee_block) > block_start)
1263                 /* The hole exists at the beginning of original file. */
1264                 seq_start = le32_to_cpu(ext_cur->ee_block);
1265         else
1266                 seq_start = block_start;
1267
1268         /* No blocks within the specified range. */
1269         if (le32_to_cpu(ext_cur->ee_block) > block_end) {
1270                 ext4_debug("ext4 move extent: The specified range of file "
1271                                                         "may be the hole\n");
1272                 ret1 = -EINVAL;
1273                 goto out;
1274         }
1275
1276         /* Adjust start blocks */
1277         add_blocks = min(le32_to_cpu(ext_cur->ee_block) +
1278                          ext4_ext_get_actual_len(ext_cur), block_end + 1) -
1279                      max(le32_to_cpu(ext_cur->ee_block), block_start);
1280
1281         while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) {
1282                 seq_blocks += add_blocks;
1283
1284                 /* Adjust tail blocks */
1285                 if (seq_start + seq_blocks - 1 > block_end)
1286                         seq_blocks = block_end - seq_start + 1;
1287
1288                 ext_prev = ext_cur;
1289                 last_extent = mext_next_extent(orig_inode, holecheck_path,
1290                                                 &ext_cur);
1291                 if (last_extent < 0) {
1292                         ret1 = last_extent;
1293                         break;
1294                 }
1295                 add_blocks = ext4_ext_get_actual_len(ext_cur);
1296
1297                 /*
1298                  * Extend the length of contiguous block (seq_blocks)
1299                  * if extents are contiguous.
1300                  */
1301                 if (ext4_can_extents_be_merged(orig_inode,
1302                                                ext_prev, ext_cur) &&
1303                     block_end >= le32_to_cpu(ext_cur->ee_block) &&
1304                     !last_extent)
1305                         continue;
1306
1307                 /* Is original extent is uninitialized */
1308                 uninit = ext4_ext_is_uninitialized(ext_prev);
1309
1310                 data_offset_in_page = seq_start % blocks_per_page;
1311
1312                 /*
1313                  * Calculate data blocks count that should be swapped
1314                  * at the first page.
1315                  */
1316                 if (data_offset_in_page + seq_blocks > blocks_per_page) {
1317                         /* Swapped blocks are across pages */
1318                         block_len_in_page =
1319                                         blocks_per_page - data_offset_in_page;
1320                 } else {
1321                         /* Swapped blocks are in a page */
1322                         block_len_in_page = seq_blocks;
1323                 }
1324
1325                 orig_page_offset = seq_start >>
1326                                 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1327                 seq_end_page = (seq_start + seq_blocks - 1) >>
1328                                 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1329                 seq_start = le32_to_cpu(ext_cur->ee_block);
1330                 rest_blocks = seq_blocks;
1331
1332                 /*
1333                  * Up semaphore to avoid following problems:
1334                  * a. transaction deadlock among ext4_journal_start,
1335                  *    ->write_begin via pagefault, and jbd2_journal_commit
1336                  * b. racing with ->readpage, ->write_begin, and ext4_get_block
1337                  *    in move_extent_per_page
1338                  */
1339                 double_up_write_data_sem(orig_inode, donor_inode);
1340
1341                 while (orig_page_offset <= seq_end_page) {
1342
1343                         /* Swap original branches with new branches */
1344                         block_len_in_page = move_extent_per_page(
1345                                                 o_filp, donor_inode,
1346                                                 orig_page_offset,
1347                                                 data_offset_in_page,
1348                                                 block_len_in_page, uninit,
1349                                                 &ret1);
1350
1351                         /* Count how many blocks we have exchanged */
1352                         *moved_len += block_len_in_page;
1353                         if (ret1 < 0)
1354                                 break;
1355                         if (*moved_len > len) {
1356                                 ext4_error(orig_inode->i_sb,
1357                                         "We replaced blocks too much! "
1358                                         "sum of replaced: %llu requested: %llu",
1359                                         *moved_len, len);
1360                                 ret1 = -EIO;
1361                                 break;
1362                         }
1363
1364                         orig_page_offset++;
1365                         data_offset_in_page = 0;
1366                         rest_blocks -= block_len_in_page;
1367                         if (rest_blocks > blocks_per_page)
1368                                 block_len_in_page = blocks_per_page;
1369                         else
1370                                 block_len_in_page = rest_blocks;
1371                 }
1372
1373                 double_down_write_data_sem(orig_inode, donor_inode);
1374                 if (ret1 < 0)
1375                         break;
1376
1377                 /* Decrease buffer counter */
1378                 if (holecheck_path)
1379                         ext4_ext_drop_refs(holecheck_path);
1380                 ret1 = get_ext_path(orig_inode, seq_start, &holecheck_path);
1381                 if (ret1)
1382                         break;
1383                 depth = holecheck_path->p_depth;
1384
1385                 /* Decrease buffer counter */
1386                 if (orig_path)
1387                         ext4_ext_drop_refs(orig_path);
1388                 ret1 = get_ext_path(orig_inode, seq_start, &orig_path);
1389                 if (ret1)
1390                         break;
1391
1392                 ext_cur = holecheck_path[depth].p_ext;
1393                 add_blocks = ext4_ext_get_actual_len(ext_cur);
1394                 seq_blocks = 0;
1395
1396         }
1397 out:
1398         if (*moved_len) {
1399                 ext4_discard_preallocations(orig_inode);
1400                 ext4_discard_preallocations(donor_inode);
1401         }
1402
1403         if (orig_path) {
1404                 ext4_ext_drop_refs(orig_path);
1405                 kfree(orig_path);
1406         }
1407         if (holecheck_path) {
1408                 ext4_ext_drop_refs(holecheck_path);
1409                 kfree(holecheck_path);
1410         }
1411         double_up_write_data_sem(orig_inode, donor_inode);
1412         ret2 = mext_inode_double_unlock(orig_inode, donor_inode);
1413
1414         if (ret1)
1415                 return ret1;
1416         else if (ret2)
1417                 return ret2;
1418
1419         return 0;
1420 }