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}