linux/fs/ext4/move_extent.c
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   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 <linux/slab.h>
  19#include "ext4_jbd2.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 */
  32static inline int
  33get_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 */
  54static void
  55copy_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 */
  76static int
  77mext_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 = ext4_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 = ext4_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                                        ext4_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                                        ext4_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 */
 148static int
 149mext_check_null_inode(struct inode *inode1, struct inode *inode2,
 150                      const char *function, unsigned int line)
 151{
 152        int ret = 0;
 153
 154        if (inode1 == NULL) {
 155                __ext4_error(inode2->i_sb, function, line,
 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, line,
 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 */
 176static void
 177double_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 */
 202static void
 203double_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 */
 223static int
 224mext_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, ext4_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, ext4_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        }
 313out:
 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 */
 337static void
 338mext_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++], ext4_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 */
 391static int
 392mext_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 */
 472static int
 473mext_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        start_ext.ee_block = end_ext.ee_block = 0;
 485        o_start = o_end = oext = orig_path[depth].p_ext;
 486        oext_alen = ext4_ext_get_actual_len(oext);
 487        start_ext.ee_len = end_ext.ee_len = 0;
 488
 489        new_ext.ee_block = cpu_to_le32(*from);
 490        ext4_ext_store_pblock(&new_ext, ext4_ext_pblock(dext));
 491        new_ext.ee_len = dext->ee_len;
 492        new_ext_alen = ext4_ext_get_actual_len(&new_ext);
 493        new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
 494
 495        /*
 496         * Case: original extent is first
 497         * oext      |--------|
 498         * new_ext      |--|
 499         * start_ext |--|
 500         */
 501        if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) &&
 502                le32_to_cpu(new_ext.ee_block) <
 503                le32_to_cpu(oext->ee_block) + oext_alen) {
 504                start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
 505                                               le32_to_cpu(oext->ee_block));
 506                start_ext.ee_block = oext->ee_block;
 507                copy_extent_status(oext, &start_ext);
 508        } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
 509                prev_ext = oext - 1;
 510                /*
 511                 * We can merge new_ext into previous extent,
 512                 * if these are contiguous and same extent type.
 513                 */
 514                if (ext4_can_extents_be_merged(orig_inode, prev_ext,
 515                                               &new_ext)) {
 516                        o_start = prev_ext;
 517                        start_ext.ee_len = cpu_to_le16(
 518                                ext4_ext_get_actual_len(prev_ext) +
 519                                new_ext_alen);
 520                        start_ext.ee_block = oext->ee_block;
 521                        copy_extent_status(prev_ext, &start_ext);
 522                        new_ext.ee_len = 0;
 523                }
 524        }
 525
 526        /*
 527         * Case: new_ext_end must be less than oext
 528         * oext      |-----------|
 529         * new_ext       |-------|
 530         */
 531        if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) {
 532                EXT4_ERROR_INODE(orig_inode,
 533                        "new_ext_end(%u) should be less than or equal to "
 534                        "oext->ee_block(%u) + oext_alen(%d) - 1",
 535                        new_ext_end, le32_to_cpu(oext->ee_block),
 536                        oext_alen);
 537                ret = -EIO;
 538                goto out;
 539        }
 540
 541        /*
 542         * Case: new_ext is smaller than original extent
 543         * oext    |---------------|
 544         * new_ext |-----------|
 545         * end_ext             |---|
 546         */
 547        if (le32_to_cpu(oext->ee_block) <= new_ext_end &&
 548                new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) {
 549                end_ext.ee_len =
 550                        cpu_to_le16(le32_to_cpu(oext->ee_block) +
 551                        oext_alen - 1 - new_ext_end);
 552                copy_extent_status(oext, &end_ext);
 553                end_ext_alen = ext4_ext_get_actual_len(&end_ext);
 554                ext4_ext_store_pblock(&end_ext,
 555                        (ext4_ext_pblock(o_end) + oext_alen - end_ext_alen));
 556                end_ext.ee_block =
 557                        cpu_to_le32(le32_to_cpu(o_end->ee_block) +
 558                        oext_alen - end_ext_alen);
 559        }
 560
 561        ret = mext_insert_extents(handle, orig_inode, orig_path, o_start,
 562                                o_end, &start_ext, &new_ext, &end_ext);
 563out:
 564        return ret;
 565}
 566
 567/**
 568 * mext_calc_swap_extents - Calculate extents for extent swapping.
 569 *
 570 * @tmp_dext:           the extent that will belong to the original inode
 571 * @tmp_oext:           the extent that will belong to the donor inode
 572 * @orig_off:           block offset of original inode
 573 * @donor_off:          block offset of donor inode
 574 * @max_count:          the maximum length of extents
 575 *
 576 * Return 0 on success, or a negative error value on failure.
 577 */
 578static int
 579mext_calc_swap_extents(struct ext4_extent *tmp_dext,
 580                              struct ext4_extent *tmp_oext,
 581                              ext4_lblk_t orig_off, ext4_lblk_t donor_off,
 582                              ext4_lblk_t max_count)
 583{
 584        ext4_lblk_t diff, orig_diff;
 585        struct ext4_extent dext_old, oext_old;
 586
 587        BUG_ON(orig_off != donor_off);
 588
 589        /* original and donor extents have to cover the same block offset */
 590        if (orig_off < le32_to_cpu(tmp_oext->ee_block) ||
 591            le32_to_cpu(tmp_oext->ee_block) +
 592                        ext4_ext_get_actual_len(tmp_oext) - 1 < orig_off)
 593                return -ENODATA;
 594
 595        if (orig_off < le32_to_cpu(tmp_dext->ee_block) ||
 596            le32_to_cpu(tmp_dext->ee_block) +
 597                        ext4_ext_get_actual_len(tmp_dext) - 1 < orig_off)
 598                return -ENODATA;
 599
 600        dext_old = *tmp_dext;
 601        oext_old = *tmp_oext;
 602
 603        /* When tmp_dext is too large, pick up the target range. */
 604        diff = donor_off - le32_to_cpu(tmp_dext->ee_block);
 605
 606        ext4_ext_store_pblock(tmp_dext, ext4_ext_pblock(tmp_dext) + diff);
 607        tmp_dext->ee_block =
 608                        cpu_to_le32(le32_to_cpu(tmp_dext->ee_block) + diff);
 609        tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_dext->ee_len) - diff);
 610
 611        if (max_count < ext4_ext_get_actual_len(tmp_dext))
 612                tmp_dext->ee_len = cpu_to_le16(max_count);
 613
 614        orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block);
 615        ext4_ext_store_pblock(tmp_oext, ext4_ext_pblock(tmp_oext) + orig_diff);
 616
 617        /* Adjust extent length if donor extent is larger than orig */
 618        if (ext4_ext_get_actual_len(tmp_dext) >
 619            ext4_ext_get_actual_len(tmp_oext) - orig_diff)
 620                tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) -
 621                                                orig_diff);
 622
 623        tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext));
 624
 625        copy_extent_status(&oext_old, tmp_dext);
 626        copy_extent_status(&dext_old, tmp_oext);
 627
 628        return 0;
 629}
 630
 631/**
 632 * mext_replace_branches - Replace original extents with new extents
 633 *
 634 * @handle:             journal handle
 635 * @orig_inode:         original inode
 636 * @donor_inode:        donor inode
 637 * @from:               block offset of orig_inode
 638 * @count:              block count to be replaced
 639 * @err:                pointer to save return value
 640 *
 641 * Replace original inode extents and donor inode extents page by page.
 642 * We implement this replacement in the following three steps:
 643 * 1. Save the block information of original and donor inodes into
 644 *    dummy extents.
 645 * 2. Change the block information of original inode to point at the
 646 *    donor inode blocks.
 647 * 3. Change the block information of donor inode to point at the saved
 648 *    original inode blocks in the dummy extents.
 649 *
 650 * Return replaced block count.
 651 */
 652static int
 653mext_replace_branches(handle_t *handle, struct inode *orig_inode,
 654                           struct inode *donor_inode, ext4_lblk_t from,
 655                           ext4_lblk_t count, int *err)
 656{
 657        struct ext4_ext_path *orig_path = NULL;
 658        struct ext4_ext_path *donor_path = NULL;
 659        struct ext4_extent *oext, *dext;
 660        struct ext4_extent tmp_dext, tmp_oext;
 661        ext4_lblk_t orig_off = from, donor_off = from;
 662        int depth;
 663        int replaced_count = 0;
 664        int dext_alen;
 665
 666        /* Protect extent trees against block allocations via delalloc */
 667        double_down_write_data_sem(orig_inode, donor_inode);
 668
 669        /* Get the original extent for the block "orig_off" */
 670        *err = get_ext_path(orig_inode, orig_off, &orig_path);
 671        if (*err)
 672                goto out;
 673
 674        /* Get the donor extent for the head */
 675        *err = get_ext_path(donor_inode, donor_off, &donor_path);
 676        if (*err)
 677                goto out;
 678        depth = ext_depth(orig_inode);
 679        oext = orig_path[depth].p_ext;
 680        tmp_oext = *oext;
 681
 682        depth = ext_depth(donor_inode);
 683        dext = donor_path[depth].p_ext;
 684        tmp_dext = *dext;
 685
 686        *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
 687                                      donor_off, count);
 688        if (*err)
 689                goto out;
 690
 691        /* Loop for the donor extents */
 692        while (1) {
 693                /* The extent for donor must be found. */
 694                if (!dext) {
 695                        EXT4_ERROR_INODE(donor_inode,
 696                                   "The extent for donor must be found");
 697                        *err = -EIO;
 698                        goto out;
 699                } else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) {
 700                        EXT4_ERROR_INODE(donor_inode,
 701                                "Donor offset(%u) and the first block of donor "
 702                                "extent(%u) should be equal",
 703                                donor_off,
 704                                le32_to_cpu(tmp_dext.ee_block));
 705                        *err = -EIO;
 706                        goto out;
 707                }
 708
 709                /* Set donor extent to orig extent */
 710                *err = mext_leaf_block(handle, orig_inode,
 711                                           orig_path, &tmp_dext, &orig_off);
 712                if (*err)
 713                        goto out;
 714
 715                /* Set orig extent to donor extent */
 716                *err = mext_leaf_block(handle, donor_inode,
 717                                           donor_path, &tmp_oext, &donor_off);
 718                if (*err)
 719                        goto out;
 720
 721                dext_alen = ext4_ext_get_actual_len(&tmp_dext);
 722                replaced_count += dext_alen;
 723                donor_off += dext_alen;
 724                orig_off += dext_alen;
 725
 726                /* Already moved the expected blocks */
 727                if (replaced_count >= count)
 728                        break;
 729
 730                if (orig_path)
 731                        ext4_ext_drop_refs(orig_path);
 732                *err = get_ext_path(orig_inode, orig_off, &orig_path);
 733                if (*err)
 734                        goto out;
 735                depth = ext_depth(orig_inode);
 736                oext = orig_path[depth].p_ext;
 737                tmp_oext = *oext;
 738
 739                if (donor_path)
 740                        ext4_ext_drop_refs(donor_path);
 741                *err = get_ext_path(donor_inode, donor_off, &donor_path);
 742                if (*err)
 743                        goto out;
 744                depth = ext_depth(donor_inode);
 745                dext = donor_path[depth].p_ext;
 746                tmp_dext = *dext;
 747
 748                *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
 749                                           donor_off, count - replaced_count);
 750                if (*err)
 751                        goto out;
 752        }
 753
 754out:
 755        if (orig_path) {
 756                ext4_ext_drop_refs(orig_path);
 757                kfree(orig_path);
 758        }
 759        if (donor_path) {
 760                ext4_ext_drop_refs(donor_path);
 761                kfree(donor_path);
 762        }
 763
 764        ext4_ext_invalidate_cache(orig_inode);
 765        ext4_ext_invalidate_cache(donor_inode);
 766
 767        double_up_write_data_sem(orig_inode, donor_inode);
 768
 769        return replaced_count;
 770}
 771
 772/**
 773 * move_extent_per_page - Move extent data per page
 774 *
 775 * @o_filp:                     file structure of original file
 776 * @donor_inode:                donor inode
 777 * @orig_page_offset:           page index on original file
 778 * @data_offset_in_page:        block index where data swapping starts
 779 * @block_len_in_page:          the number of blocks to be swapped
 780 * @uninit:                     orig extent is uninitialized or not
 781 * @err:                        pointer to save return value
 782 *
 783 * Save the data in original inode blocks and replace original inode extents
 784 * with donor inode extents by calling mext_replace_branches().
 785 * Finally, write out the saved data in new original inode blocks. Return
 786 * replaced block count.
 787 */
 788static int
 789move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
 790                  pgoff_t orig_page_offset, int data_offset_in_page,
 791                  int block_len_in_page, int uninit, int *err)
 792{
 793        struct inode *orig_inode = o_filp->f_dentry->d_inode;
 794        struct address_space *mapping = orig_inode->i_mapping;
 795        struct buffer_head *bh;
 796        struct page *page = NULL;
 797        const struct address_space_operations *a_ops = mapping->a_ops;
 798        handle_t *handle;
 799        ext4_lblk_t orig_blk_offset;
 800        long long offs = orig_page_offset << PAGE_CACHE_SHIFT;
 801        unsigned long blocksize = orig_inode->i_sb->s_blocksize;
 802        unsigned int w_flags = 0;
 803        unsigned int tmp_data_size, data_size, replaced_size;
 804        void *fsdata;
 805        int i, jblocks;
 806        int err2 = 0;
 807        int replaced_count = 0;
 808        int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
 809
 810        /*
 811         * It needs twice the amount of ordinary journal buffers because
 812         * inode and donor_inode may change each different metadata blocks.
 813         */
 814        jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
 815        handle = ext4_journal_start(orig_inode, jblocks);
 816        if (IS_ERR(handle)) {
 817                *err = PTR_ERR(handle);
 818                return 0;
 819        }
 820
 821        if (segment_eq(get_fs(), KERNEL_DS))
 822                w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
 823
 824        orig_blk_offset = orig_page_offset * blocks_per_page +
 825                data_offset_in_page;
 826
 827        /*
 828         * If orig extent is uninitialized one,
 829         * it's not necessary force the page into memory
 830         * and then force it to be written out again.
 831         * Just swap data blocks between orig and donor.
 832         */
 833        if (uninit) {
 834                replaced_count = mext_replace_branches(handle, orig_inode,
 835                                                donor_inode, orig_blk_offset,
 836                                                block_len_in_page, err);
 837                goto out2;
 838        }
 839
 840        offs = (long long)orig_blk_offset << orig_inode->i_blkbits;
 841
 842        /* Calculate data_size */
 843        if ((orig_blk_offset + block_len_in_page - 1) ==
 844            ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
 845                /* Replace the last block */
 846                tmp_data_size = orig_inode->i_size & (blocksize - 1);
 847                /*
 848                 * If data_size equal zero, it shows data_size is multiples of
 849                 * blocksize. So we set appropriate value.
 850                 */
 851                if (tmp_data_size == 0)
 852                        tmp_data_size = blocksize;
 853
 854                data_size = tmp_data_size +
 855                        ((block_len_in_page - 1) << orig_inode->i_blkbits);
 856        } else
 857                data_size = block_len_in_page << orig_inode->i_blkbits;
 858
 859        replaced_size = data_size;
 860
 861        *err = a_ops->write_begin(o_filp, mapping, offs, data_size, w_flags,
 862                                 &page, &fsdata);
 863        if (unlikely(*err < 0))
 864                goto out;
 865
 866        if (!PageUptodate(page)) {
 867                mapping->a_ops->readpage(o_filp, page);
 868                lock_page(page);
 869        }
 870
 871        /*
 872         * try_to_release_page() doesn't call releasepage in writeback mode.
 873         * We should care about the order of writing to the same file
 874         * by multiple move extent processes.
 875         * It needs to call wait_on_page_writeback() to wait for the
 876         * writeback of the page.
 877         */
 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
 916out:
 917        if (unlikely(page)) {
 918                if (PageLocked(page))
 919                        unlock_page(page);
 920                page_cache_release(page);
 921                ext4_journal_stop(handle);
 922        }
 923out2:
 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 */
 945static int
 946mext_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        if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
 962                return -EPERM;
 963
 964        /* Ext4 move extent does not support swapfile */
 965        if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
 966                ext4_debug("ext4 move extent: The argument files should "
 967                        "not be swapfile [ino:orig %lu, donor %lu]\n",
 968                        orig_inode->i_ino, donor_inode->i_ino);
 969                return -EINVAL;
 970        }
 971
 972        /* Files should be in the same ext4 FS */
 973        if (orig_inode->i_sb != donor_inode->i_sb) {
 974                ext4_debug("ext4 move extent: The argument files "
 975                        "should be in same FS [ino:orig %lu, donor %lu]\n",
 976                        orig_inode->i_ino, donor_inode->i_ino);
 977                return -EINVAL;
 978        }
 979
 980        /* Ext4 move extent supports only extent based file */
 981        if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
 982                ext4_debug("ext4 move extent: orig file is not extents "
 983                        "based file [ino:orig %lu]\n", orig_inode->i_ino);
 984                return -EOPNOTSUPP;
 985        } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
 986                ext4_debug("ext4 move extent: donor file is not extents "
 987                        "based file [ino:donor %lu]\n", donor_inode->i_ino);
 988                return -EOPNOTSUPP;
 989        }
 990
 991        if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
 992                ext4_debug("ext4 move extent: File size is 0 byte\n");
 993                return -EINVAL;
 994        }
 995
 996        /* Start offset should be same */
 997        if (orig_start != donor_start) {
 998                ext4_debug("ext4 move extent: orig and donor's start "
 999                        "offset are not same [ino:orig %lu, donor %lu]\n",
1000                        orig_inode->i_ino, donor_inode->i_ino);
1001                return -EINVAL;
1002        }
1003
1004        if ((orig_start >= EXT_MAX_BLOCKS) ||
1005            (donor_start >= EXT_MAX_BLOCKS) ||
1006            (*len > EXT_MAX_BLOCKS) ||
1007            (orig_start + *len >= EXT_MAX_BLOCKS))  {
1008                ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
1009                        "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
1010                        orig_inode->i_ino, donor_inode->i_ino);
1011                return -EINVAL;
1012        }
1013
1014        if (orig_inode->i_size > donor_inode->i_size) {
1015                donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits;
1016                /* TODO: eliminate this artificial restriction */
1017                if (orig_start >= donor_blocks) {
1018                        ext4_debug("ext4 move extent: orig start offset "
1019                        "[%llu] should be less than donor file blocks "
1020                        "[%u] [ino:orig %lu, donor %lu]\n",
1021                        orig_start, donor_blocks,
1022                        orig_inode->i_ino, donor_inode->i_ino);
1023                        return -EINVAL;
1024                }
1025
1026                /* TODO: eliminate this artificial restriction */
1027                if (orig_start + *len > donor_blocks) {
1028                        ext4_debug("ext4 move extent: End offset [%llu] should "
1029                                "be less than donor file blocks [%u]."
1030                                "So adjust length from %llu to %llu "
1031                                "[ino:orig %lu, donor %lu]\n",
1032                                orig_start + *len, donor_blocks,
1033                                *len, donor_blocks - orig_start,
1034                                orig_inode->i_ino, donor_inode->i_ino);
1035                        *len = donor_blocks - orig_start;
1036                }
1037        } else {
1038                orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits;
1039                if (orig_start >= orig_blocks) {
1040                        ext4_debug("ext4 move extent: start offset [%llu] "
1041                                "should be less than original file blocks "
1042                                "[%u] [ino:orig %lu, donor %lu]\n",
1043                                 orig_start, orig_blocks,
1044                                orig_inode->i_ino, donor_inode->i_ino);
1045                        return -EINVAL;
1046                }
1047
1048                if (orig_start + *len > orig_blocks) {
1049                        ext4_debug("ext4 move extent: Adjust length "
1050                                "from %llu to %llu. Because it should be "
1051                                "less than original file blocks "
1052                                "[ino:orig %lu, donor %lu]\n",
1053                                *len, orig_blocks - orig_start,
1054                                orig_inode->i_ino, donor_inode->i_ino);
1055                        *len = orig_blocks - orig_start;
1056                }
1057        }
1058
1059        if (!*len) {
1060                ext4_debug("ext4 move extent: len should not be 0 "
1061                        "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
1062                        donor_inode->i_ino);
1063                return -EINVAL;
1064        }
1065
1066        return 0;
1067}
1068
1069/**
1070 * mext_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
1071 *
1072 * @inode1:     the inode structure
1073 * @inode2:     the inode structure
1074 *
1075 * Lock two inodes' i_mutex by i_ino order.
1076 * If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
1077 */
1078static int
1079mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
1080{
1081        int ret = 0;
1082
1083        BUG_ON(inode1 == NULL && inode2 == NULL);
1084
1085        ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
1086        if (ret < 0)
1087                goto out;
1088
1089        if (inode1 == inode2) {
1090                mutex_lock(&inode1->i_mutex);
1091                goto out;
1092        }
1093
1094        if (inode1->i_ino < inode2->i_ino) {
1095                mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
1096                mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
1097        } else {
1098                mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
1099                mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
1100        }
1101
1102out:
1103        return ret;
1104}
1105
1106/**
1107 * mext_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
1108 *
1109 * @inode1:     the inode that is released first
1110 * @inode2:     the inode that is released second
1111 *
1112 * If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
1113 */
1114
1115static int
1116mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
1117{
1118        int ret = 0;
1119
1120        BUG_ON(inode1 == NULL && inode2 == NULL);
1121
1122        ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
1123        if (ret < 0)
1124                goto out;
1125
1126        if (inode1)
1127                mutex_unlock(&inode1->i_mutex);
1128
1129        if (inode2 && inode2 != inode1)
1130                mutex_unlock(&inode2->i_mutex);
1131
1132out:
1133        return ret;
1134}
1135
1136/**
1137 * ext4_move_extents - Exchange the specified range of a file
1138 *
1139 * @o_filp:             file structure of the original file
1140 * @d_filp:             file structure of the donor file
1141 * @orig_start:         start offset in block for orig
1142 * @donor_start:        start offset in block for donor
1143 * @len:                the number of blocks to be moved
1144 * @moved_len:          moved block length
1145 *
1146 * This function returns 0 and moved block length is set in moved_len
1147 * if succeed, otherwise returns error value.
1148 *
1149 * Note: ext4_move_extents() proceeds the following order.
1150 * 1:ext4_move_extents() calculates the last block number of moving extent
1151 *   function by the start block number (orig_start) and the number of blocks
1152 *   to be moved (len) specified as arguments.
1153 *   If the {orig, donor}_start points a hole, the extent's start offset
1154 *   pointed by ext_cur (current extent), holecheck_path, orig_path are set
1155 *   after hole behind.
1156 * 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
1157 *   or the ext_cur exceeds the block_end which is last logical block number.
1158 * 3:To get the length of continues area, call mext_next_extent()
1159 *   specified with the ext_cur (initial value is holecheck_path) re-cursive,
1160 *   until find un-continuous extent, the start logical block number exceeds
1161 *   the block_end or the extent points to the last extent.
1162 * 4:Exchange the original inode data with donor inode data
1163 *   from orig_page_offset to seq_end_page.
1164 *   The start indexes of data are specified as arguments.
1165 *   That of the original inode is orig_page_offset,
1166 *   and the donor inode is also orig_page_offset
1167 *   (To easily handle blocksize != pagesize case, the offset for the
1168 *   donor inode is block unit).
1169 * 5:Update holecheck_path and orig_path to points a next proceeding extent,
1170 *   then returns to step 2.
1171 * 6:Release holecheck_path, orig_path and set the len to moved_len
1172 *   which shows the number of moved blocks.
1173 *   The moved_len is useful for the command to calculate the file offset
1174 *   for starting next move extent ioctl.
1175 * 7:Return 0 on success, or a negative error value on failure.
1176 */
1177int
1178ext4_move_extents(struct file *o_filp, struct file *d_filp,
1179                 __u64 orig_start, __u64 donor_start, __u64 len,
1180                 __u64 *moved_len)
1181{
1182        struct inode *orig_inode = o_filp->f_dentry->d_inode;
1183        struct inode *donor_inode = d_filp->f_dentry->d_inode;
1184        struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL;
1185        struct ext4_extent *ext_prev, *ext_cur, *ext_dummy;
1186        ext4_lblk_t block_start = orig_start;
1187        ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
1188        ext4_lblk_t rest_blocks;
1189        pgoff_t orig_page_offset = 0, seq_end_page;
1190        int ret1, ret2, depth, last_extent = 0;
1191        int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
1192        int data_offset_in_page;
1193        int block_len_in_page;
1194        int uninit;
1195
1196        /* orig and donor should be different file */
1197        if (orig_inode->i_ino == donor_inode->i_ino) {
1198                ext4_debug("ext4 move extent: The argument files should not "
1199                        "be same file [ino:orig %lu, donor %lu]\n",
1200                        orig_inode->i_ino, donor_inode->i_ino);
1201                return -EINVAL;
1202        }
1203
1204        /* Regular file check */
1205        if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
1206                ext4_debug("ext4 move extent: The argument files should be "
1207                        "regular file [ino:orig %lu, donor %lu]\n",
1208                        orig_inode->i_ino, donor_inode->i_ino);
1209                return -EINVAL;
1210        }
1211
1212        /* Protect orig and donor inodes against a truncate */
1213        ret1 = mext_inode_double_lock(orig_inode, donor_inode);
1214        if (ret1 < 0)
1215                return ret1;
1216
1217        /* Protect extent tree against block allocations via delalloc */
1218        double_down_write_data_sem(orig_inode, donor_inode);
1219        /* Check the filesystem environment whether move_extent can be done */
1220        ret1 = mext_check_arguments(orig_inode, donor_inode, orig_start,
1221                                    donor_start, &len);
1222        if (ret1)
1223                goto out;
1224
1225        file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
1226        block_end = block_start + len - 1;
1227        if (file_end < block_end)
1228                len -= block_end - file_end;
1229
1230        ret1 = get_ext_path(orig_inode, block_start, &orig_path);
1231        if (ret1)
1232                goto out;
1233
1234        /* Get path structure to check the hole */
1235        ret1 = get_ext_path(orig_inode, block_start, &holecheck_path);
1236        if (ret1)
1237                goto out;
1238
1239        depth = ext_depth(orig_inode);
1240        ext_cur = holecheck_path[depth].p_ext;
1241
1242        /*
1243         * Get proper starting location of block replacement if block_start was
1244         * within the hole.
1245         */
1246        if (le32_to_cpu(ext_cur->ee_block) +
1247                ext4_ext_get_actual_len(ext_cur) - 1 < block_start) {
1248                /*
1249                 * The hole exists between extents or the tail of
1250                 * original file.
1251                 */
1252                last_extent = mext_next_extent(orig_inode,
1253                                        holecheck_path, &ext_cur);
1254                if (last_extent < 0) {
1255                        ret1 = last_extent;
1256                        goto out;
1257                }
1258                last_extent = mext_next_extent(orig_inode, orig_path,
1259                                                        &ext_dummy);
1260                if (last_extent < 0) {
1261                        ret1 = last_extent;
1262                        goto out;
1263                }
1264                seq_start = le32_to_cpu(ext_cur->ee_block);
1265        } else if (le32_to_cpu(ext_cur->ee_block) > block_start)
1266                /* The hole exists at the beginning of original file. */
1267                seq_start = le32_to_cpu(ext_cur->ee_block);
1268        else
1269                seq_start = block_start;
1270
1271        /* No blocks within the specified range. */
1272        if (le32_to_cpu(ext_cur->ee_block) > block_end) {
1273                ext4_debug("ext4 move extent: The specified range of file "
1274                                                        "may be the hole\n");
1275                ret1 = -EINVAL;
1276                goto out;
1277        }
1278
1279        /* Adjust start blocks */
1280        add_blocks = min(le32_to_cpu(ext_cur->ee_block) +
1281                         ext4_ext_get_actual_len(ext_cur), block_end + 1) -
1282                     max(le32_to_cpu(ext_cur->ee_block), block_start);
1283
1284        while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) {
1285                seq_blocks += add_blocks;
1286
1287                /* Adjust tail blocks */
1288                if (seq_start + seq_blocks - 1 > block_end)
1289                        seq_blocks = block_end - seq_start + 1;
1290
1291                ext_prev = ext_cur;
1292                last_extent = mext_next_extent(orig_inode, holecheck_path,
1293                                                &ext_cur);
1294                if (last_extent < 0) {
1295                        ret1 = last_extent;
1296                        break;
1297                }
1298                add_blocks = ext4_ext_get_actual_len(ext_cur);
1299
1300                /*
1301                 * Extend the length of contiguous block (seq_blocks)
1302                 * if extents are contiguous.
1303                 */
1304                if (ext4_can_extents_be_merged(orig_inode,
1305                                               ext_prev, ext_cur) &&
1306                    block_end >= le32_to_cpu(ext_cur->ee_block) &&
1307                    !last_extent)
1308                        continue;
1309
1310                /* Is original extent is uninitialized */
1311                uninit = ext4_ext_is_uninitialized(ext_prev);
1312
1313                data_offset_in_page = seq_start % blocks_per_page;
1314
1315                /*
1316                 * Calculate data blocks count that should be swapped
1317                 * at the first page.
1318                 */
1319                if (data_offset_in_page + seq_blocks > blocks_per_page) {
1320                        /* Swapped blocks are across pages */
1321                        block_len_in_page =
1322                                        blocks_per_page - data_offset_in_page;
1323                } else {
1324                        /* Swapped blocks are in a page */
1325                        block_len_in_page = seq_blocks;
1326                }
1327
1328                orig_page_offset = seq_start >>
1329                                (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1330                seq_end_page = (seq_start + seq_blocks - 1) >>
1331                                (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1332                seq_start = le32_to_cpu(ext_cur->ee_block);
1333                rest_blocks = seq_blocks;
1334
1335                /*
1336                 * Up semaphore to avoid following problems:
1337                 * a. transaction deadlock among ext4_journal_start,
1338                 *    ->write_begin via pagefault, and jbd2_journal_commit
1339                 * b. racing with ->readpage, ->write_begin, and ext4_get_block
1340                 *    in move_extent_per_page
1341                 */
1342                double_up_write_data_sem(orig_inode, donor_inode);
1343
1344                while (orig_page_offset <= seq_end_page) {
1345
1346                        /* Swap original branches with new branches */
1347                        block_len_in_page = move_extent_per_page(
1348                                                o_filp, donor_inode,
1349                                                orig_page_offset,
1350                                                data_offset_in_page,
1351                                                block_len_in_page, uninit,
1352                                                &ret1);
1353
1354                        /* Count how many blocks we have exchanged */
1355                        *moved_len += block_len_in_page;
1356                        if (ret1 < 0)
1357                                break;
1358                        if (*moved_len > len) {
1359                                EXT4_ERROR_INODE(orig_inode,
1360                                        "We replaced blocks too much! "
1361                                        "sum of replaced: %llu requested: %llu",
1362                                        *moved_len, len);
1363                                ret1 = -EIO;
1364                                break;
1365                        }
1366
1367                        orig_page_offset++;
1368                        data_offset_in_page = 0;
1369                        rest_blocks -= block_len_in_page;
1370                        if (rest_blocks > blocks_per_page)
1371                                block_len_in_page = blocks_per_page;
1372                        else
1373                                block_len_in_page = rest_blocks;
1374                }
1375
1376                double_down_write_data_sem(orig_inode, donor_inode);
1377                if (ret1 < 0)
1378                        break;
1379
1380                /* Decrease buffer counter */
1381                if (holecheck_path)
1382                        ext4_ext_drop_refs(holecheck_path);
1383                ret1 = get_ext_path(orig_inode, seq_start, &holecheck_path);
1384                if (ret1)
1385                        break;
1386                depth = holecheck_path->p_depth;
1387
1388                /* Decrease buffer counter */
1389                if (orig_path)
1390                        ext4_ext_drop_refs(orig_path);
1391                ret1 = get_ext_path(orig_inode, seq_start, &orig_path);
1392                if (ret1)
1393                        break;
1394
1395                ext_cur = holecheck_path[depth].p_ext;
1396                add_blocks = ext4_ext_get_actual_len(ext_cur);
1397                seq_blocks = 0;
1398
1399        }
1400out:
1401        if (*moved_len) {
1402                ext4_discard_preallocations(orig_inode);
1403                ext4_discard_preallocations(donor_inode);
1404        }
1405
1406        if (orig_path) {
1407                ext4_ext_drop_refs(orig_path);
1408                kfree(orig_path);
1409        }
1410        if (holecheck_path) {
1411                ext4_ext_drop_refs(holecheck_path);
1412                kfree(holecheck_path);
1413        }
1414        double_up_write_data_sem(orig_inode, donor_inode);
1415        ret2 = mext_inode_double_unlock(orig_inode, donor_inode);
1416
1417        if (ret1)
1418                return ret1;
1419        else if (ret2)
1420                return ret2;
1421
1422        return 0;
1423}
1424
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