1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext2/inode.c
   4 *
   5 * Copyright (C) 1992, 1993, 1994, 1995
   6 * Remy Card (card@masi.ibp.fr)
   7 * Laboratoire MASI - Institut Blaise Pascal
   8 * Universite Pierre et Marie Curie (Paris VI)
   9 *
  10 *  from
  11 *
  12 *  linux/fs/minix/inode.c
  13 *
  14 *  Copyright (C) 1991, 1992  Linus Torvalds
  15 *
  16 *  Goal-directed block allocation by Stephen Tweedie
  17 * 	(sct@dcs.ed.ac.uk), 1993, 1998
  18 *  Big-endian to little-endian byte-swapping/bitmaps by
  19 *        David S. Miller (davem@caip.rutgers.edu), 1995
  20 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  21 * 	(jj@sunsite.ms.mff.cuni.cz)
  22 *
  23 *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
  24 */
  25
  26#include <linux/time.h>
  27#include <linux/highuid.h>
  28#include <linux/pagemap.h>
  29#include <linux/dax.h>
  30#include <linux/blkdev.h>
  31#include <linux/quotaops.h>
  32#include <linux/writeback.h>
  33#include <linux/buffer_head.h>
  34#include <linux/mpage.h>
  35#include <linux/fiemap.h>
  36#include <linux/iomap.h>
  37#include <linux/namei.h>
  38#include <linux/uio.h>
  39#include "ext2.h"
  40#include "acl.h"
  41#include "xattr.h"
  42
  43static int __ext2_write_inode(struct inode *inode, int do_sync);
  44
  45/*
  46 * Test whether an inode is a fast symlink.
  47 */
  48static inline int ext2_inode_is_fast_symlink(struct inode *inode)
  49{
  50	int ea_blocks = EXT2_I(inode)->i_file_acl ?
  51		(inode->i_sb->s_blocksize >> 9) : 0;
  52
  53	return (S_ISLNK(inode->i_mode) &&
  54		inode->i_blocks - ea_blocks == 0);
  55}
  56
  57static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
  58
  59static void ext2_write_failed(struct address_space *mapping, loff_t to)
  60{
  61	struct inode *inode = mapping->host;
  62
  63	if (to > inode->i_size) {
  64		truncate_pagecache(inode, inode->i_size);
  65		ext2_truncate_blocks(inode, inode->i_size);
  66	}
  67}
  68
  69/*
  70 * Called at the last iput() if i_nlink is zero.
  71 */
  72void ext2_evict_inode(struct inode * inode)
  73{
  74	struct ext2_block_alloc_info *rsv;
  75	int want_delete = 0;
  76
  77	if (!inode->i_nlink && !is_bad_inode(inode)) {
  78		want_delete = 1;
  79		dquot_initialize(inode);
  80	} else {
  81		dquot_drop(inode);
  82	}
  83
  84	truncate_inode_pages_final(&inode->i_data);
  85
  86	if (want_delete) {
  87		sb_start_intwrite(inode->i_sb);
  88		/* set dtime */
  89		EXT2_I(inode)->i_dtime	= get_seconds();
  90		mark_inode_dirty(inode);
  91		__ext2_write_inode(inode, inode_needs_sync(inode));
  92		/* truncate to 0 */
  93		inode->i_size = 0;
  94		if (inode->i_blocks)
  95			ext2_truncate_blocks(inode, 0);
  96		ext2_xattr_delete_inode(inode);
  97	}
  98
  99	invalidate_inode_buffers(inode);
 100	clear_inode(inode);
 101
 102	ext2_discard_reservation(inode);
 103	rsv = EXT2_I(inode)->i_block_alloc_info;
 104	EXT2_I(inode)->i_block_alloc_info = NULL;
 105	if (unlikely(rsv))
 106		kfree(rsv);
 107
 108	if (want_delete) {
 109		ext2_free_inode(inode);
 110		sb_end_intwrite(inode->i_sb);
 111	}
 112}
 113
 114typedef struct {
 115	__le32	*p;
 116	__le32	key;
 117	struct buffer_head *bh;
 118} Indirect;
 119
 120static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
 121{
 122	p->key = *(p->p = v);
 123	p->bh = bh;
 124}
 125
 126static inline int verify_chain(Indirect *from, Indirect *to)
 127{
 128	while (from <= to && from->key == *from->p)
 129		from++;
 130	return (from > to);
 131}
 132
 133/**
 134 *	ext2_block_to_path - parse the block number into array of offsets
 135 *	@inode: inode in question (we are only interested in its superblock)
 136 *	@i_block: block number to be parsed
 137 *	@offsets: array to store the offsets in
 138 *      @boundary: set this non-zero if the referred-to block is likely to be
 139 *             followed (on disk) by an indirect block.
 140 *	To store the locations of file's data ext2 uses a data structure common
 141 *	for UNIX filesystems - tree of pointers anchored in the inode, with
 142 *	data blocks at leaves and indirect blocks in intermediate nodes.
 143 *	This function translates the block number into path in that tree -
 144 *	return value is the path length and @offsets[n] is the offset of
 145 *	pointer to (n+1)th node in the nth one. If @block is out of range
 146 *	(negative or too large) warning is printed and zero returned.
 147 *
 148 *	Note: function doesn't find node addresses, so no IO is needed. All
 149 *	we need to know is the capacity of indirect blocks (taken from the
 150 *	inode->i_sb).
 151 */
 152
 153/*
 154 * Portability note: the last comparison (check that we fit into triple
 155 * indirect block) is spelled differently, because otherwise on an
 156 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 157 * if our filesystem had 8Kb blocks. We might use long long, but that would
 158 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 159 * i_block would have to be negative in the very beginning, so we would not
 160 * get there at all.
 161 */
 162
 163static int ext2_block_to_path(struct inode *inode,
 164			long i_block, int offsets[4], int *boundary)
 165{
 166	int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
 167	int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
 168	const long direct_blocks = EXT2_NDIR_BLOCKS,
 169		indirect_blocks = ptrs,
 170		double_blocks = (1 << (ptrs_bits * 2));
 171	int n = 0;
 172	int final = 0;
 173
 174	if (i_block < 0) {
 175		ext2_msg(inode->i_sb, KERN_WARNING,
 176			"warning: %s: block < 0", __func__);
 177	} else if (i_block < direct_blocks) {
 178		offsets[n++] = i_block;
 179		final = direct_blocks;
 180	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
 181		offsets[n++] = EXT2_IND_BLOCK;
 182		offsets[n++] = i_block;
 183		final = ptrs;
 184	} else if ((i_block -= indirect_blocks) < double_blocks) {
 185		offsets[n++] = EXT2_DIND_BLOCK;
 186		offsets[n++] = i_block >> ptrs_bits;
 187		offsets[n++] = i_block & (ptrs - 1);
 188		final = ptrs;
 189	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
 190		offsets[n++] = EXT2_TIND_BLOCK;
 191		offsets[n++] = i_block >> (ptrs_bits * 2);
 192		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
 193		offsets[n++] = i_block & (ptrs - 1);
 194		final = ptrs;
 195	} else {
 196		ext2_msg(inode->i_sb, KERN_WARNING,
 197			"warning: %s: block is too big", __func__);
 198	}
 199	if (boundary)
 200		*boundary = final - 1 - (i_block & (ptrs - 1));
 201
 202	return n;
 203}
 204
 205/**
 206 *	ext2_get_branch - read the chain of indirect blocks leading to data
 207 *	@inode: inode in question
 208 *	@depth: depth of the chain (1 - direct pointer, etc.)
 209 *	@offsets: offsets of pointers in inode/indirect blocks
 210 *	@chain: place to store the result
 211 *	@err: here we store the error value
 212 *
 213 *	Function fills the array of triples <key, p, bh> and returns %NULL
 214 *	if everything went OK or the pointer to the last filled triple
 215 *	(incomplete one) otherwise. Upon the return chain[i].key contains
 216 *	the number of (i+1)-th block in the chain (as it is stored in memory,
 217 *	i.e. little-endian 32-bit), chain[i].p contains the address of that
 218 *	number (it points into struct inode for i==0 and into the bh->b_data
 219 *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 220 *	block for i>0 and NULL for i==0. In other words, it holds the block
 221 *	numbers of the chain, addresses they were taken from (and where we can
 222 *	verify that chain did not change) and buffer_heads hosting these
 223 *	numbers.
 224 *
 225 *	Function stops when it stumbles upon zero pointer (absent block)
 226 *		(pointer to last triple returned, *@err == 0)
 227 *	or when it gets an IO error reading an indirect block
 228 *		(ditto, *@err == -EIO)
 229 *	or when it notices that chain had been changed while it was reading
 230 *		(ditto, *@err == -EAGAIN)
 231 *	or when it reads all @depth-1 indirect blocks successfully and finds
 232 *	the whole chain, all way to the data (returns %NULL, *err == 0).
 233 */
 234static Indirect *ext2_get_branch(struct inode *inode,
 235				 int depth,
 236				 int *offsets,
 237				 Indirect chain[4],
 238				 int *err)
 239{
 240	struct super_block *sb = inode->i_sb;
 241	Indirect *p = chain;
 242	struct buffer_head *bh;
 243
 244	*err = 0;
 245	/* i_data is not going away, no lock needed */
 246	add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
 247	if (!p->key)
 248		goto no_block;
 249	while (--depth) {
 250		bh = sb_bread(sb, le32_to_cpu(p->key));
 251		if (!bh)
 252			goto failure;
 253		read_lock(&EXT2_I(inode)->i_meta_lock);
 254		if (!verify_chain(chain, p))
 255			goto changed;
 256		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
 257		read_unlock(&EXT2_I(inode)->i_meta_lock);
 258		if (!p->key)
 259			goto no_block;
 260	}
 261	return NULL;
 262
 263changed:
 264	read_unlock(&EXT2_I(inode)->i_meta_lock);
 265	brelse(bh);
 266	*err = -EAGAIN;
 267	goto no_block;
 268failure:
 269	*err = -EIO;
 270no_block:
 271	return p;
 272}
 273
 274/**
 275 *	ext2_find_near - find a place for allocation with sufficient locality
 276 *	@inode: owner
 277 *	@ind: descriptor of indirect block.
 278 *
 279 *	This function returns the preferred place for block allocation.
 280 *	It is used when heuristic for sequential allocation fails.
 281 *	Rules are:
 282 *	  + if there is a block to the left of our position - allocate near it.
 283 *	  + if pointer will live in indirect block - allocate near that block.
 284 *	  + if pointer will live in inode - allocate in the same cylinder group.
 285 *
 286 * In the latter case we colour the starting block by the callers PID to
 287 * prevent it from clashing with concurrent allocations for a different inode
 288 * in the same block group.   The PID is used here so that functionally related
 289 * files will be close-by on-disk.
 290 *
 291 *	Caller must make sure that @ind is valid and will stay that way.
 292 */
 293
 294static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
 295{
 296	struct ext2_inode_info *ei = EXT2_I(inode);
 297	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
 298	__le32 *p;
 299	ext2_fsblk_t bg_start;
 300	ext2_fsblk_t colour;
 301
 302	/* Try to find previous block */
 303	for (p = ind->p - 1; p >= start; p--)
 304		if (*p)
 305			return le32_to_cpu(*p);
 306
 307	/* No such thing, so let's try location of indirect block */
 308	if (ind->bh)
 309		return ind->bh->b_blocknr;
 310
 311	/*
 312	 * It is going to be referred from inode itself? OK, just put it into
 313	 * the same cylinder group then.
 314	 */
 315	bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
 316	colour = (current->pid % 16) *
 317			(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 318	return bg_start + colour;
 319}
 320
 321/**
 322 *	ext2_find_goal - find a preferred place for allocation.
 323 *	@inode: owner
 324 *	@block:  block we want
 325 *	@partial: pointer to the last triple within a chain
 326 *
 327 *	Returns preferred place for a block (the goal).
 328 */
 329
 330static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
 331					  Indirect *partial)
 332{
 333	struct ext2_block_alloc_info *block_i;
 334
 335	block_i = EXT2_I(inode)->i_block_alloc_info;
 336
 337	/*
 338	 * try the heuristic for sequential allocation,
 339	 * failing that at least try to get decent locality.
 340	 */
 341	if (block_i && (block == block_i->last_alloc_logical_block + 1)
 342		&& (block_i->last_alloc_physical_block != 0)) {
 343		return block_i->last_alloc_physical_block + 1;
 344	}
 345
 346	return ext2_find_near(inode, partial);
 347}
 348
 349/**
 350 *	ext2_blks_to_allocate: Look up the block map and count the number
 351 *	of direct blocks need to be allocated for the given branch.
 352 *
 353 * 	@branch: chain of indirect blocks
 354 *	@k: number of blocks need for indirect blocks
 355 *	@blks: number of data blocks to be mapped.
 356 *	@blocks_to_boundary:  the offset in the indirect block
 357 *
 358 *	return the total number of blocks to be allocate, including the
 359 *	direct and indirect blocks.
 360 */
 361static int
 362ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
 363		int blocks_to_boundary)
 364{
 365	unsigned long count = 0;
 366
 367	/*
 368	 * Simple case, [t,d]Indirect block(s) has not allocated yet
 369	 * then it's clear blocks on that path have not allocated
 370	 */
 371	if (k > 0) {
 372		/* right now don't hanel cross boundary allocation */
 373		if (blks < blocks_to_boundary + 1)
 374			count += blks;
 375		else
 376			count += blocks_to_boundary + 1;
 377		return count;
 378	}
 379
 380	count++;
 381	while (count < blks && count <= blocks_to_boundary
 382		&& le32_to_cpu(*(branch[0].p + count)) == 0) {
 383		count++;
 384	}
 385	return count;
 386}
 387
 388/**
 389 *	ext2_alloc_blocks: multiple allocate blocks needed for a branch
 390 *	@indirect_blks: the number of blocks need to allocate for indirect
 391 *			blocks
 392 *
 393 *	@new_blocks: on return it will store the new block numbers for
 394 *	the indirect blocks(if needed) and the first direct block,
 395 *	@blks:	on return it will store the total number of allocated
 396 *		direct blocks
 
 
 397 */
 398static int ext2_alloc_blocks(struct inode *inode,
 399			ext2_fsblk_t goal, int indirect_blks, int blks,
 400			ext2_fsblk_t new_blocks[4], int *err)
 401{
 402	int target, i;
 403	unsigned long count = 0;
 404	int index = 0;
 405	ext2_fsblk_t current_block = 0;
 406	int ret = 0;
 407
 408	/*
 409	 * Here we try to allocate the requested multiple blocks at once,
 410	 * on a best-effort basis.
 411	 * To build a branch, we should allocate blocks for
 412	 * the indirect blocks(if not allocated yet), and at least
 413	 * the first direct block of this branch.  That's the
 414	 * minimum number of blocks need to allocate(required)
 415	 */
 416	target = blks + indirect_blks;
 417
 418	while (1) {
 419		count = target;
 420		/* allocating blocks for indirect blocks and direct blocks */
 421		current_block = ext2_new_blocks(inode,goal,&count,err);
 422		if (*err)
 423			goto failed_out;
 424
 425		target -= count;
 426		/* allocate blocks for indirect blocks */
 427		while (index < indirect_blks && count) {
 428			new_blocks[index++] = current_block++;
 429			count--;
 430		}
 431
 432		if (count > 0)
 433			break;
 434	}
 435
 436	/* save the new block number for the first direct block */
 437	new_blocks[index] = current_block;
 438
 439	/* total number of blocks allocated for direct blocks */
 440	ret = count;
 441	*err = 0;
 442	return ret;
 443failed_out:
 444	for (i = 0; i <index; i++)
 445		ext2_free_blocks(inode, new_blocks[i], 1);
 446	if (index)
 447		mark_inode_dirty(inode);
 448	return ret;
 449}
 450
 451/**
 452 *	ext2_alloc_branch - allocate and set up a chain of blocks.
 453 *	@inode: owner
 454 *	@num: depth of the chain (number of blocks to allocate)
 
 
 455 *	@offsets: offsets (in the blocks) to store the pointers to next.
 456 *	@branch: place to store the chain in.
 457 *
 458 *	This function allocates @num blocks, zeroes out all but the last one,
 459 *	links them into chain and (if we are synchronous) writes them to disk.
 460 *	In other words, it prepares a branch that can be spliced onto the
 461 *	inode. It stores the information about that chain in the branch[], in
 462 *	the same format as ext2_get_branch() would do. We are calling it after
 463 *	we had read the existing part of chain and partial points to the last
 464 *	triple of that (one with zero ->key). Upon the exit we have the same
 465 *	picture as after the successful ext2_get_block(), except that in one
 466 *	place chain is disconnected - *branch->p is still zero (we did not
 467 *	set the last link), but branch->key contains the number that should
 468 *	be placed into *branch->p to fill that gap.
 469 *
 470 *	If allocation fails we free all blocks we've allocated (and forget
 471 *	their buffer_heads) and return the error value the from failed
 472 *	ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 473 *	as described above and return 0.
 474 */
 475
 476static int ext2_alloc_branch(struct inode *inode,
 477			int indirect_blks, int *blks, ext2_fsblk_t goal,
 478			int *offsets, Indirect *branch)
 479{
 480	int blocksize = inode->i_sb->s_blocksize;
 481	int i, n = 0;
 482	int err = 0;
 483	struct buffer_head *bh;
 484	int num;
 485	ext2_fsblk_t new_blocks[4];
 486	ext2_fsblk_t current_block;
 487
 488	num = ext2_alloc_blocks(inode, goal, indirect_blks,
 489				*blks, new_blocks, &err);
 490	if (err)
 491		return err;
 492
 493	branch[0].key = cpu_to_le32(new_blocks[0]);
 494	/*
 495	 * metadata blocks and data blocks are allocated.
 496	 */
 497	for (n = 1; n <= indirect_blks;  n++) {
 498		/*
 499		 * Get buffer_head for parent block, zero it out
 500		 * and set the pointer to new one, then send
 501		 * parent to disk.
 502		 */
 503		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 504		if (unlikely(!bh)) {
 505			err = -ENOMEM;
 506			goto failed;
 507		}
 508		branch[n].bh = bh;
 509		lock_buffer(bh);
 510		memset(bh->b_data, 0, blocksize);
 511		branch[n].p = (__le32 *) bh->b_data + offsets[n];
 512		branch[n].key = cpu_to_le32(new_blocks[n]);
 513		*branch[n].p = branch[n].key;
 514		if ( n == indirect_blks) {
 515			current_block = new_blocks[n];
 516			/*
 517			 * End of chain, update the last new metablock of
 518			 * the chain to point to the new allocated
 519			 * data blocks numbers
 520			 */
 521			for (i=1; i < num; i++)
 522				*(branch[n].p + i) = cpu_to_le32(++current_block);
 523		}
 524		set_buffer_uptodate(bh);
 525		unlock_buffer(bh);
 526		mark_buffer_dirty_inode(bh, inode);
 527		/* We used to sync bh here if IS_SYNC(inode).
 528		 * But we now rely upon generic_write_sync()
 529		 * and b_inode_buffers.  But not for directories.
 530		 */
 531		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
 532			sync_dirty_buffer(bh);
 533	}
 534	*blks = num;
 535	return err;
 536
 537failed:
 538	for (i = 1; i < n; i++)
 539		bforget(branch[i].bh);
 540	for (i = 0; i < indirect_blks; i++)
 541		ext2_free_blocks(inode, new_blocks[i], 1);
 542	ext2_free_blocks(inode, new_blocks[i], num);
 543	return err;
 544}
 545
 546/**
 547 * ext2_splice_branch - splice the allocated branch onto inode.
 548 * @inode: owner
 549 * @block: (logical) number of block we are adding
 550 * @where: location of missing link
 551 * @num:   number of indirect blocks we are adding
 552 * @blks:  number of direct blocks we are adding
 553 *
 554 * This function fills the missing link and does all housekeeping needed in
 555 * inode (->i_blocks, etc.). In case of success we end up with the full
 556 * chain to new block and return 0.
 557 */
 558static void ext2_splice_branch(struct inode *inode,
 559			long block, Indirect *where, int num, int blks)
 560{
 561	int i;
 562	struct ext2_block_alloc_info *block_i;
 563	ext2_fsblk_t current_block;
 564
 565	block_i = EXT2_I(inode)->i_block_alloc_info;
 566
 567	/* XXX LOCKING probably should have i_meta_lock ?*/
 568	/* That's it */
 569
 570	*where->p = where->key;
 571
 572	/*
 573	 * Update the host buffer_head or inode to point to more just allocated
 574	 * direct blocks blocks
 575	 */
 576	if (num == 0 && blks > 1) {
 577		current_block = le32_to_cpu(where->key) + 1;
 578		for (i = 1; i < blks; i++)
 579			*(where->p + i ) = cpu_to_le32(current_block++);
 580	}
 581
 582	/*
 583	 * update the most recently allocated logical & physical block
 584	 * in i_block_alloc_info, to assist find the proper goal block for next
 585	 * allocation
 586	 */
 587	if (block_i) {
 588		block_i->last_alloc_logical_block = block + blks - 1;
 589		block_i->last_alloc_physical_block =
 590				le32_to_cpu(where[num].key) + blks - 1;
 591	}
 592
 593	/* We are done with atomic stuff, now do the rest of housekeeping */
 594
 595	/* had we spliced it onto indirect block? */
 596	if (where->bh)
 597		mark_buffer_dirty_inode(where->bh, inode);
 598
 599	inode->i_ctime = current_time(inode);
 600	mark_inode_dirty(inode);
 601}
 602
 603/*
 604 * Allocation strategy is simple: if we have to allocate something, we will
 605 * have to go the whole way to leaf. So let's do it before attaching anything
 606 * to tree, set linkage between the newborn blocks, write them if sync is
 607 * required, recheck the path, free and repeat if check fails, otherwise
 608 * set the last missing link (that will protect us from any truncate-generated
 609 * removals - all blocks on the path are immune now) and possibly force the
 610 * write on the parent block.
 611 * That has a nice additional property: no special recovery from the failed
 612 * allocations is needed - we simply release blocks and do not touch anything
 613 * reachable from inode.
 614 *
 615 * `handle' can be NULL if create == 0.
 616 *
 617 * return > 0, # of blocks mapped or allocated.
 618 * return = 0, if plain lookup failed.
 619 * return < 0, error case.
 620 */
 621static int ext2_get_blocks(struct inode *inode,
 622			   sector_t iblock, unsigned long maxblocks,
 623			   u32 *bno, bool *new, bool *boundary,
 624			   int create)
 625{
 626	int err;
 627	int offsets[4];
 628	Indirect chain[4];
 629	Indirect *partial;
 630	ext2_fsblk_t goal;
 631	int indirect_blks;
 632	int blocks_to_boundary = 0;
 633	int depth;
 634	struct ext2_inode_info *ei = EXT2_I(inode);
 635	int count = 0;
 636	ext2_fsblk_t first_block = 0;
 637
 638	BUG_ON(maxblocks == 0);
 639
 640	depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 641
 642	if (depth == 0)
 643		return -EIO;
 644
 645	partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 646	/* Simplest case - block found, no allocation needed */
 647	if (!partial) {
 648		first_block = le32_to_cpu(chain[depth - 1].key);
 649		count++;
 650		/*map more blocks*/
 651		while (count < maxblocks && count <= blocks_to_boundary) {
 652			ext2_fsblk_t blk;
 653
 654			if (!verify_chain(chain, chain + depth - 1)) {
 655				/*
 656				 * Indirect block might be removed by
 657				 * truncate while we were reading it.
 658				 * Handling of that case: forget what we've
 659				 * got now, go to reread.
 660				 */
 661				err = -EAGAIN;
 662				count = 0;
 663				partial = chain + depth - 1;
 664				break;
 665			}
 666			blk = le32_to_cpu(*(chain[depth-1].p + count));
 667			if (blk == first_block + count)
 668				count++;
 669			else
 670				break;
 671		}
 672		if (err != -EAGAIN)
 673			goto got_it;
 674	}
 675
 676	/* Next simple case - plain lookup or failed read of indirect block */
 677	if (!create || err == -EIO)
 678		goto cleanup;
 679
 680	mutex_lock(&ei->truncate_mutex);
 681	/*
 682	 * If the indirect block is missing while we are reading
 683	 * the chain(ext2_get_branch() returns -EAGAIN err), or
 684	 * if the chain has been changed after we grab the semaphore,
 685	 * (either because another process truncated this branch, or
 686	 * another get_block allocated this branch) re-grab the chain to see if
 687	 * the request block has been allocated or not.
 688	 *
 689	 * Since we already block the truncate/other get_block
 690	 * at this point, we will have the current copy of the chain when we
 691	 * splice the branch into the tree.
 692	 */
 693	if (err == -EAGAIN || !verify_chain(chain, partial)) {
 694		while (partial > chain) {
 695			brelse(partial->bh);
 696			partial--;
 697		}
 698		partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 699		if (!partial) {
 700			count++;
 701			mutex_unlock(&ei->truncate_mutex);
 702			if (err)
 703				goto cleanup;
 704			goto got_it;
 705		}
 
 
 
 
 
 706	}
 707
 708	/*
 709	 * Okay, we need to do block allocation.  Lazily initialize the block
 710	 * allocation info here if necessary
 711	*/
 712	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
 713		ext2_init_block_alloc_info(inode);
 714
 715	goal = ext2_find_goal(inode, iblock, partial);
 716
 717	/* the number of blocks need to allocate for [d,t]indirect blocks */
 718	indirect_blks = (chain + depth) - partial - 1;
 719	/*
 720	 * Next look up the indirect map to count the totoal number of
 721	 * direct blocks to allocate for this branch.
 722	 */
 723	count = ext2_blks_to_allocate(partial, indirect_blks,
 724					maxblocks, blocks_to_boundary);
 725	/*
 726	 * XXX ???? Block out ext2_truncate while we alter the tree
 727	 */
 728	err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
 729				offsets + (partial - chain), partial);
 730
 731	if (err) {
 732		mutex_unlock(&ei->truncate_mutex);
 733		goto cleanup;
 734	}
 735
 736	if (IS_DAX(inode)) {
 737		/*
 738		 * We must unmap blocks before zeroing so that writeback cannot
 739		 * overwrite zeros with stale data from block device page cache.
 740		 */
 741		clean_bdev_aliases(inode->i_sb->s_bdev,
 742				   le32_to_cpu(chain[depth-1].key),
 743				   count);
 744		/*
 745		 * block must be initialised before we put it in the tree
 746		 * so that it's not found by another thread before it's
 747		 * initialised
 748		 */
 749		err = sb_issue_zeroout(inode->i_sb,
 750				le32_to_cpu(chain[depth-1].key), count,
 751				GFP_NOFS);
 752		if (err) {
 753			mutex_unlock(&ei->truncate_mutex);
 754			goto cleanup;
 755		}
 756	}
 757	*new = true;
 758
 759	ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
 760	mutex_unlock(&ei->truncate_mutex);
 761got_it:
 762	if (count > blocks_to_boundary)
 763		*boundary = true;
 764	err = count;
 765	/* Clean up and exit */
 766	partial = chain + depth - 1;	/* the whole chain */
 767cleanup:
 768	while (partial > chain) {
 769		brelse(partial->bh);
 770		partial--;
 771	}
 772	if (err > 0)
 773		*bno = le32_to_cpu(chain[depth-1].key);
 774	return err;
 775}
 776
 777int ext2_get_block(struct inode *inode, sector_t iblock,
 778		struct buffer_head *bh_result, int create)
 779{
 780	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
 781	bool new = false, boundary = false;
 782	u32 bno;
 783	int ret;
 784
 785	ret = ext2_get_blocks(inode, iblock, max_blocks, &bno, &new, &boundary,
 786			create);
 787	if (ret <= 0)
 788		return ret;
 789
 790	map_bh(bh_result, inode->i_sb, bno);
 791	bh_result->b_size = (ret << inode->i_blkbits);
 792	if (new)
 793		set_buffer_new(bh_result);
 794	if (boundary)
 795		set_buffer_boundary(bh_result);
 796	return 0;
 797
 798}
 799
 800#ifdef CONFIG_FS_DAX
 801static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 802		unsigned flags, struct iomap *iomap)
 803{
 804	unsigned int blkbits = inode->i_blkbits;
 805	unsigned long first_block = offset >> blkbits;
 806	unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits;
 807	struct ext2_sb_info *sbi = EXT2_SB(inode->i_sb);
 808	bool new = false, boundary = false;
 809	u32 bno;
 810	int ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 811
 812	ret = ext2_get_blocks(inode, first_block, max_blocks,
 813			&bno, &new, &boundary, flags & IOMAP_WRITE);
 814	if (ret < 0)
 815		return ret;
 816
 817	iomap->flags = 0;
 818	iomap->bdev = inode->i_sb->s_bdev;
 819	iomap->offset = (u64)first_block << blkbits;
 820	iomap->dax_dev = sbi->s_daxdev;
 
 
 
 821
 822	if (ret == 0) {
 
 
 
 
 
 
 823		iomap->type = IOMAP_HOLE;
 824		iomap->addr = IOMAP_NULL_ADDR;
 825		iomap->length = 1 << blkbits;
 826	} else {
 827		iomap->type = IOMAP_MAPPED;
 828		iomap->addr = (u64)bno << blkbits;
 
 
 829		iomap->length = (u64)ret << blkbits;
 830		iomap->flags |= IOMAP_F_MERGED;
 831	}
 832
 833	if (new)
 834		iomap->flags |= IOMAP_F_NEW;
 835	return 0;
 836}
 837
 838static int
 839ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
 840		ssize_t written, unsigned flags, struct iomap *iomap)
 841{
 
 
 
 
 
 
 
 842	if (iomap->type == IOMAP_MAPPED &&
 843	    written < length &&
 844	    (flags & IOMAP_WRITE))
 845		ext2_write_failed(inode->i_mapping, offset + length);
 846	return 0;
 847}
 848
 849const struct iomap_ops ext2_iomap_ops = {
 850	.iomap_begin		= ext2_iomap_begin,
 851	.iomap_end		= ext2_iomap_end,
 852};
 853#else
 854/* Define empty ops for !CONFIG_FS_DAX case to avoid ugly ifdefs */
 855const struct iomap_ops ext2_iomap_ops;
 856#endif /* CONFIG_FS_DAX */
 857
 858int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 859		u64 start, u64 len)
 860{
 861	return generic_block_fiemap(inode, fieinfo, start, len,
 862				    ext2_get_block);
 863}
 864
 865static int ext2_writepage(struct page *page, struct writeback_control *wbc)
 866{
 867	return block_write_full_page(page, ext2_get_block, wbc);
 
 
 
 868}
 869
 870static int ext2_readpage(struct file *file, struct page *page)
 871{
 872	return mpage_readpage(page, ext2_get_block);
 873}
 874
 875static int
 876ext2_readpages(struct file *file, struct address_space *mapping,
 877		struct list_head *pages, unsigned nr_pages)
 878{
 879	return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
 880}
 881
 882static int
 883ext2_write_begin(struct file *file, struct address_space *mapping,
 884		loff_t pos, unsigned len, unsigned flags,
 885		struct page **pagep, void **fsdata)
 886{
 887	int ret;
 888
 889	ret = block_write_begin(mapping, pos, len, flags, pagep,
 890				ext2_get_block);
 891	if (ret < 0)
 892		ext2_write_failed(mapping, pos + len);
 893	return ret;
 894}
 895
 896static int ext2_write_end(struct file *file, struct address_space *mapping,
 897			loff_t pos, unsigned len, unsigned copied,
 898			struct page *page, void *fsdata)
 899{
 900	int ret;
 901
 902	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 903	if (ret < len)
 904		ext2_write_failed(mapping, pos + len);
 905	return ret;
 906}
 907
 908static int
 909ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
 910		loff_t pos, unsigned len, unsigned flags,
 911		struct page **pagep, void **fsdata)
 912{
 913	int ret;
 914
 915	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
 916			       ext2_get_block);
 917	if (ret < 0)
 918		ext2_write_failed(mapping, pos + len);
 919	return ret;
 920}
 921
 922static int ext2_nobh_writepage(struct page *page,
 923			struct writeback_control *wbc)
 924{
 925	return nobh_writepage(page, ext2_get_block, wbc);
 926}
 927
 928static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 929{
 930	return generic_block_bmap(mapping,block,ext2_get_block);
 931}
 932
 933static ssize_t
 934ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 935{
 936	struct file *file = iocb->ki_filp;
 937	struct address_space *mapping = file->f_mapping;
 938	struct inode *inode = mapping->host;
 939	size_t count = iov_iter_count(iter);
 940	loff_t offset = iocb->ki_pos;
 941	ssize_t ret;
 942
 943	ret = blockdev_direct_IO(iocb, inode, iter, ext2_get_block);
 944	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 945		ext2_write_failed(mapping, offset + count);
 946	return ret;
 947}
 948
 949static int
 950ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
 951{
 952	return mpage_writepages(mapping, wbc, ext2_get_block);
 953}
 954
 955static int
 956ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
 957{
 958	return dax_writeback_mapping_range(mapping,
 959			mapping->host->i_sb->s_bdev, wbc);
 
 960}
 961
 962const struct address_space_operations ext2_aops = {
 963	.readpage		= ext2_readpage,
 964	.readpages		= ext2_readpages,
 965	.writepage		= ext2_writepage,
 
 966	.write_begin		= ext2_write_begin,
 967	.write_end		= ext2_write_end,
 968	.bmap			= ext2_bmap,
 969	.direct_IO		= ext2_direct_IO,
 970	.writepages		= ext2_writepages,
 971	.migratepage		= buffer_migrate_page,
 972	.is_partially_uptodate	= block_is_partially_uptodate,
 973	.error_remove_page	= generic_error_remove_page,
 974};
 975
 976const struct address_space_operations ext2_nobh_aops = {
 977	.readpage		= ext2_readpage,
 978	.readpages		= ext2_readpages,
 979	.writepage		= ext2_nobh_writepage,
 980	.write_begin		= ext2_nobh_write_begin,
 981	.write_end		= nobh_write_end,
 982	.bmap			= ext2_bmap,
 983	.direct_IO		= ext2_direct_IO,
 984	.writepages		= ext2_writepages,
 985	.migratepage		= buffer_migrate_page,
 986	.error_remove_page	= generic_error_remove_page,
 987};
 988
 989static const struct address_space_operations ext2_dax_aops = {
 990	.writepages		= ext2_dax_writepages,
 991	.direct_IO		= noop_direct_IO,
 992	.set_page_dirty		= noop_set_page_dirty,
 993	.invalidatepage		= noop_invalidatepage,
 994};
 995
 996/*
 997 * Probably it should be a library function... search for first non-zero word
 998 * or memcmp with zero_page, whatever is better for particular architecture.
 999 * Linus?
1000 */
1001static inline int all_zeroes(__le32 *p, __le32 *q)
1002{
1003	while (p < q)
1004		if (*p++)
1005			return 0;
1006	return 1;
1007}
1008
1009/**
1010 *	ext2_find_shared - find the indirect blocks for partial truncation.
1011 *	@inode:	  inode in question
1012 *	@depth:	  depth of the affected branch
1013 *	@offsets: offsets of pointers in that branch (see ext2_block_to_path)
1014 *	@chain:	  place to store the pointers to partial indirect blocks
1015 *	@top:	  place to the (detached) top of branch
1016 *
1017 *	This is a helper function used by ext2_truncate().
1018 *
1019 *	When we do truncate() we may have to clean the ends of several indirect
1020 *	blocks but leave the blocks themselves alive. Block is partially
1021 *	truncated if some data below the new i_size is referred from it (and
1022 *	it is on the path to the first completely truncated data block, indeed).
1023 *	We have to free the top of that path along with everything to the right
1024 *	of the path. Since no allocation past the truncation point is possible
1025 *	until ext2_truncate() finishes, we may safely do the latter, but top
1026 *	of branch may require special attention - pageout below the truncation
1027 *	point might try to populate it.
1028 *
1029 *	We atomically detach the top of branch from the tree, store the block
1030 *	number of its root in *@top, pointers to buffer_heads of partially
1031 *	truncated blocks - in @chain[].bh and pointers to their last elements
1032 *	that should not be removed - in @chain[].p. Return value is the pointer
1033 *	to last filled element of @chain.
1034 *
1035 *	The work left to caller to do the actual freeing of subtrees:
1036 *		a) free the subtree starting from *@top
1037 *		b) free the subtrees whose roots are stored in
1038 *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
1039 *		c) free the subtrees growing from the inode past the @chain[0].p
1040 *			(no partially truncated stuff there).
1041 */
1042
1043static Indirect *ext2_find_shared(struct inode *inode,
1044				int depth,
1045				int offsets[4],
1046				Indirect chain[4],
1047				__le32 *top)
1048{
1049	Indirect *partial, *p;
1050	int k, err;
1051
1052	*top = 0;
1053	for (k = depth; k > 1 && !offsets[k-1]; k--)
1054		;
1055	partial = ext2_get_branch(inode, k, offsets, chain, &err);
1056	if (!partial)
1057		partial = chain + k-1;
1058	/*
1059	 * If the branch acquired continuation since we've looked at it -
1060	 * fine, it should all survive and (new) top doesn't belong to us.
1061	 */
1062	write_lock(&EXT2_I(inode)->i_meta_lock);
1063	if (!partial->key && *partial->p) {
1064		write_unlock(&EXT2_I(inode)->i_meta_lock);
1065		goto no_top;
1066	}
1067	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1068		;
1069	/*
1070	 * OK, we've found the last block that must survive. The rest of our
1071	 * branch should be detached before unlocking. However, if that rest
1072	 * of branch is all ours and does not grow immediately from the inode
1073	 * it's easier to cheat and just decrement partial->p.
1074	 */
1075	if (p == chain + k - 1 && p > chain) {
1076		p->p--;
1077	} else {
1078		*top = *p->p;
1079		*p->p = 0;
1080	}
1081	write_unlock(&EXT2_I(inode)->i_meta_lock);
1082
1083	while(partial > p)
1084	{
1085		brelse(partial->bh);
1086		partial--;
1087	}
1088no_top:
1089	return partial;
1090}
1091
1092/**
1093 *	ext2_free_data - free a list of data blocks
1094 *	@inode:	inode we are dealing with
1095 *	@p:	array of block numbers
1096 *	@q:	points immediately past the end of array
1097 *
1098 *	We are freeing all blocks referred from that array (numbers are
1099 *	stored as little-endian 32-bit) and updating @inode->i_blocks
1100 *	appropriately.
1101 */
1102static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1103{
1104	unsigned long block_to_free = 0, count = 0;
1105	unsigned long nr;
1106
1107	for ( ; p < q ; p++) {
1108		nr = le32_to_cpu(*p);
1109		if (nr) {
1110			*p = 0;
1111			/* accumulate blocks to free if they're contiguous */
1112			if (count == 0)
1113				goto free_this;
1114			else if (block_to_free == nr - count)
1115				count++;
1116			else {
1117				ext2_free_blocks (inode, block_to_free, count);
1118				mark_inode_dirty(inode);
1119			free_this:
1120				block_to_free = nr;
1121				count = 1;
1122			}
1123		}
1124	}
1125	if (count > 0) {
1126		ext2_free_blocks (inode, block_to_free, count);
1127		mark_inode_dirty(inode);
1128	}
1129}
1130
1131/**
1132 *	ext2_free_branches - free an array of branches
1133 *	@inode:	inode we are dealing with
1134 *	@p:	array of block numbers
1135 *	@q:	pointer immediately past the end of array
1136 *	@depth:	depth of the branches to free
1137 *
1138 *	We are freeing all blocks referred from these branches (numbers are
1139 *	stored as little-endian 32-bit) and updating @inode->i_blocks
1140 *	appropriately.
1141 */
1142static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1143{
1144	struct buffer_head * bh;
1145	unsigned long nr;
1146
1147	if (depth--) {
1148		int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1149		for ( ; p < q ; p++) {
1150			nr = le32_to_cpu(*p);
1151			if (!nr)
1152				continue;
1153			*p = 0;
1154			bh = sb_bread(inode->i_sb, nr);
1155			/*
1156			 * A read failure? Report error and clear slot
1157			 * (should be rare).
1158			 */ 
1159			if (!bh) {
1160				ext2_error(inode->i_sb, "ext2_free_branches",
1161					"Read failure, inode=%ld, block=%ld",
1162					inode->i_ino, nr);
1163				continue;
1164			}
1165			ext2_free_branches(inode,
1166					   (__le32*)bh->b_data,
1167					   (__le32*)bh->b_data + addr_per_block,
1168					   depth);
1169			bforget(bh);
1170			ext2_free_blocks(inode, nr, 1);
1171			mark_inode_dirty(inode);
1172		}
1173	} else
1174		ext2_free_data(inode, p, q);
1175}
1176
1177/* dax_sem must be held when calling this function */
1178static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1179{
1180	__le32 *i_data = EXT2_I(inode)->i_data;
1181	struct ext2_inode_info *ei = EXT2_I(inode);
1182	int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1183	int offsets[4];
1184	Indirect chain[4];
1185	Indirect *partial;
1186	__le32 nr = 0;
1187	int n;
1188	long iblock;
1189	unsigned blocksize;
1190	blocksize = inode->i_sb->s_blocksize;
1191	iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1192
1193#ifdef CONFIG_FS_DAX
1194	WARN_ON(!rwsem_is_locked(&ei->dax_sem));
1195#endif
1196
1197	n = ext2_block_to_path(inode, iblock, offsets, NULL);
1198	if (n == 0)
1199		return;
1200
1201	/*
1202	 * From here we block out all ext2_get_block() callers who want to
1203	 * modify the block allocation tree.
1204	 */
1205	mutex_lock(&ei->truncate_mutex);
1206
1207	if (n == 1) {
1208		ext2_free_data(inode, i_data+offsets[0],
1209					i_data + EXT2_NDIR_BLOCKS);
1210		goto do_indirects;
1211	}
1212
1213	partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1214	/* Kill the top of shared branch (already detached) */
1215	if (nr) {
1216		if (partial == chain)
1217			mark_inode_dirty(inode);
1218		else
1219			mark_buffer_dirty_inode(partial->bh, inode);
1220		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1221	}
1222	/* Clear the ends of indirect blocks on the shared branch */
1223	while (partial > chain) {
1224		ext2_free_branches(inode,
1225				   partial->p + 1,
1226				   (__le32*)partial->bh->b_data+addr_per_block,
1227				   (chain+n-1) - partial);
1228		mark_buffer_dirty_inode(partial->bh, inode);
1229		brelse (partial->bh);
1230		partial--;
1231	}
1232do_indirects:
1233	/* Kill the remaining (whole) subtrees */
1234	switch (offsets[0]) {
1235		default:
1236			nr = i_data[EXT2_IND_BLOCK];
1237			if (nr) {
1238				i_data[EXT2_IND_BLOCK] = 0;
1239				mark_inode_dirty(inode);
1240				ext2_free_branches(inode, &nr, &nr+1, 1);
1241			}
 
1242		case EXT2_IND_BLOCK:
1243			nr = i_data[EXT2_DIND_BLOCK];
1244			if (nr) {
1245				i_data[EXT2_DIND_BLOCK] = 0;
1246				mark_inode_dirty(inode);
1247				ext2_free_branches(inode, &nr, &nr+1, 2);
1248			}
 
1249		case EXT2_DIND_BLOCK:
1250			nr = i_data[EXT2_TIND_BLOCK];
1251			if (nr) {
1252				i_data[EXT2_TIND_BLOCK] = 0;
1253				mark_inode_dirty(inode);
1254				ext2_free_branches(inode, &nr, &nr+1, 3);
1255			}
 
1256		case EXT2_TIND_BLOCK:
1257			;
1258	}
1259
1260	ext2_discard_reservation(inode);
1261
1262	mutex_unlock(&ei->truncate_mutex);
1263}
1264
1265static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1266{
1267	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1268	    S_ISLNK(inode->i_mode)))
1269		return;
1270	if (ext2_inode_is_fast_symlink(inode))
1271		return;
1272
1273	dax_sem_down_write(EXT2_I(inode));
1274	__ext2_truncate_blocks(inode, offset);
1275	dax_sem_up_write(EXT2_I(inode));
1276}
1277
1278static int ext2_setsize(struct inode *inode, loff_t newsize)
1279{
1280	int error;
1281
1282	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1283	    S_ISLNK(inode->i_mode)))
1284		return -EINVAL;
1285	if (ext2_inode_is_fast_symlink(inode))
1286		return -EINVAL;
1287	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1288		return -EPERM;
1289
1290	inode_dio_wait(inode);
1291
1292	if (IS_DAX(inode)) {
1293		error = iomap_zero_range(inode, newsize,
1294					 PAGE_ALIGN(newsize) - newsize, NULL,
1295					 &ext2_iomap_ops);
1296	} else if (test_opt(inode->i_sb, NOBH))
1297		error = nobh_truncate_page(inode->i_mapping,
1298				newsize, ext2_get_block);
1299	else
1300		error = block_truncate_page(inode->i_mapping,
1301				newsize, ext2_get_block);
1302	if (error)
1303		return error;
1304
1305	dax_sem_down_write(EXT2_I(inode));
1306	truncate_setsize(inode, newsize);
1307	__ext2_truncate_blocks(inode, newsize);
1308	dax_sem_up_write(EXT2_I(inode));
1309
1310	inode->i_mtime = inode->i_ctime = current_time(inode);
1311	if (inode_needs_sync(inode)) {
1312		sync_mapping_buffers(inode->i_mapping);
1313		sync_inode_metadata(inode, 1);
1314	} else {
1315		mark_inode_dirty(inode);
1316	}
1317
1318	return 0;
1319}
1320
1321static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1322					struct buffer_head **p)
1323{
1324	struct buffer_head * bh;
1325	unsigned long block_group;
1326	unsigned long block;
1327	unsigned long offset;
1328	struct ext2_group_desc * gdp;
1329
1330	*p = NULL;
1331	if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1332	    ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1333		goto Einval;
1334
1335	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1336	gdp = ext2_get_group_desc(sb, block_group, NULL);
1337	if (!gdp)
1338		goto Egdp;
1339	/*
1340	 * Figure out the offset within the block group inode table
1341	 */
1342	offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1343	block = le32_to_cpu(gdp->bg_inode_table) +
1344		(offset >> EXT2_BLOCK_SIZE_BITS(sb));
1345	if (!(bh = sb_bread(sb, block)))
1346		goto Eio;
1347
1348	*p = bh;
1349	offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1350	return (struct ext2_inode *) (bh->b_data + offset);
1351
1352Einval:
1353	ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1354		   (unsigned long) ino);
1355	return ERR_PTR(-EINVAL);
1356Eio:
1357	ext2_error(sb, "ext2_get_inode",
1358		   "unable to read inode block - inode=%lu, block=%lu",
1359		   (unsigned long) ino, block);
1360Egdp:
1361	return ERR_PTR(-EIO);
1362}
1363
1364void ext2_set_inode_flags(struct inode *inode)
1365{
1366	unsigned int flags = EXT2_I(inode)->i_flags;
1367
1368	inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1369				S_DIRSYNC | S_DAX);
1370	if (flags & EXT2_SYNC_FL)
1371		inode->i_flags |= S_SYNC;
1372	if (flags & EXT2_APPEND_FL)
1373		inode->i_flags |= S_APPEND;
1374	if (flags & EXT2_IMMUTABLE_FL)
1375		inode->i_flags |= S_IMMUTABLE;
1376	if (flags & EXT2_NOATIME_FL)
1377		inode->i_flags |= S_NOATIME;
1378	if (flags & EXT2_DIRSYNC_FL)
1379		inode->i_flags |= S_DIRSYNC;
1380	if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1381		inode->i_flags |= S_DAX;
1382}
1383
1384void ext2_set_file_ops(struct inode *inode)
1385{
1386	inode->i_op = &ext2_file_inode_operations;
1387	inode->i_fop = &ext2_file_operations;
1388	if (IS_DAX(inode))
1389		inode->i_mapping->a_ops = &ext2_dax_aops;
1390	else if (test_opt(inode->i_sb, NOBH))
1391		inode->i_mapping->a_ops = &ext2_nobh_aops;
1392	else
1393		inode->i_mapping->a_ops = &ext2_aops;
1394}
1395
1396struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1397{
1398	struct ext2_inode_info *ei;
1399	struct buffer_head * bh;
1400	struct ext2_inode *raw_inode;
1401	struct inode *inode;
1402	long ret = -EIO;
1403	int n;
1404	uid_t i_uid;
1405	gid_t i_gid;
1406
1407	inode = iget_locked(sb, ino);
1408	if (!inode)
1409		return ERR_PTR(-ENOMEM);
1410	if (!(inode->i_state & I_NEW))
1411		return inode;
1412
1413	ei = EXT2_I(inode);
1414	ei->i_block_alloc_info = NULL;
1415
1416	raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1417	if (IS_ERR(raw_inode)) {
1418		ret = PTR_ERR(raw_inode);
1419 		goto bad_inode;
1420	}
1421
1422	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1423	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1424	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1425	if (!(test_opt (inode->i_sb, NO_UID32))) {
1426		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1427		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1428	}
1429	i_uid_write(inode, i_uid);
1430	i_gid_write(inode, i_gid);
1431	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1432	inode->i_size = le32_to_cpu(raw_inode->i_size);
1433	inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1434	inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1435	inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1436	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1437	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1438	/* We now have enough fields to check if the inode was active or not.
1439	 * This is needed because nfsd might try to access dead inodes
1440	 * the test is that same one that e2fsck uses
1441	 * NeilBrown 1999oct15
1442	 */
1443	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1444		/* this inode is deleted */
1445		brelse (bh);
1446		ret = -ESTALE;
1447		goto bad_inode;
1448	}
1449	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1450	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
 
1451	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1452	ei->i_frag_no = raw_inode->i_frag;
1453	ei->i_frag_size = raw_inode->i_fsize;
1454	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1455	ei->i_dir_acl = 0;
1456
1457	if (ei->i_file_acl &&
1458	    !ext2_data_block_valid(EXT2_SB(sb), ei->i_file_acl, 1)) {
1459		ext2_error(sb, "ext2_iget", "bad extended attribute block %u",
1460			   ei->i_file_acl);
1461		brelse(bh);
1462		ret = -EFSCORRUPTED;
1463		goto bad_inode;
1464	}
1465
1466	if (S_ISREG(inode->i_mode))
1467		inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1468	else
1469		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1470	if (i_size_read(inode) < 0) {
1471		ret = -EFSCORRUPTED;
1472		goto bad_inode;
1473	}
1474	ei->i_dtime = 0;
1475	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1476	ei->i_state = 0;
1477	ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1478	ei->i_dir_start_lookup = 0;
1479
1480	/*
1481	 * NOTE! The in-memory inode i_data array is in little-endian order
1482	 * even on big-endian machines: we do NOT byteswap the block numbers!
1483	 */
1484	for (n = 0; n < EXT2_N_BLOCKS; n++)
1485		ei->i_data[n] = raw_inode->i_block[n];
1486
1487	if (S_ISREG(inode->i_mode)) {
1488		ext2_set_file_ops(inode);
1489	} else if (S_ISDIR(inode->i_mode)) {
1490		inode->i_op = &ext2_dir_inode_operations;
1491		inode->i_fop = &ext2_dir_operations;
1492		if (test_opt(inode->i_sb, NOBH))
1493			inode->i_mapping->a_ops = &ext2_nobh_aops;
1494		else
1495			inode->i_mapping->a_ops = &ext2_aops;
1496	} else if (S_ISLNK(inode->i_mode)) {
1497		if (ext2_inode_is_fast_symlink(inode)) {
1498			inode->i_link = (char *)ei->i_data;
1499			inode->i_op = &ext2_fast_symlink_inode_operations;
1500			nd_terminate_link(ei->i_data, inode->i_size,
1501				sizeof(ei->i_data) - 1);
1502		} else {
1503			inode->i_op = &ext2_symlink_inode_operations;
1504			inode_nohighmem(inode);
1505			if (test_opt(inode->i_sb, NOBH))
1506				inode->i_mapping->a_ops = &ext2_nobh_aops;
1507			else
1508				inode->i_mapping->a_ops = &ext2_aops;
1509		}
1510	} else {
1511		inode->i_op = &ext2_special_inode_operations;
1512		if (raw_inode->i_block[0])
1513			init_special_inode(inode, inode->i_mode,
1514			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1515		else 
1516			init_special_inode(inode, inode->i_mode,
1517			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1518	}
1519	brelse (bh);
1520	ext2_set_inode_flags(inode);
1521	unlock_new_inode(inode);
1522	return inode;
1523	
1524bad_inode:
 
1525	iget_failed(inode);
1526	return ERR_PTR(ret);
1527}
1528
1529static int __ext2_write_inode(struct inode *inode, int do_sync)
1530{
1531	struct ext2_inode_info *ei = EXT2_I(inode);
1532	struct super_block *sb = inode->i_sb;
1533	ino_t ino = inode->i_ino;
1534	uid_t uid = i_uid_read(inode);
1535	gid_t gid = i_gid_read(inode);
1536	struct buffer_head * bh;
1537	struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1538	int n;
1539	int err = 0;
1540
1541	if (IS_ERR(raw_inode))
1542 		return -EIO;
1543
1544	/* For fields not not tracking in the in-memory inode,
1545	 * initialise them to zero for new inodes. */
1546	if (ei->i_state & EXT2_STATE_NEW)
1547		memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1548
1549	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1550	if (!(test_opt(sb, NO_UID32))) {
1551		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1552		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1553/*
1554 * Fix up interoperability with old kernels. Otherwise, old inodes get
1555 * re-used with the upper 16 bits of the uid/gid intact
1556 */
1557		if (!ei->i_dtime) {
1558			raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1559			raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1560		} else {
1561			raw_inode->i_uid_high = 0;
1562			raw_inode->i_gid_high = 0;
1563		}
1564	} else {
1565		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1566		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1567		raw_inode->i_uid_high = 0;
1568		raw_inode->i_gid_high = 0;
1569	}
1570	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1571	raw_inode->i_size = cpu_to_le32(inode->i_size);
1572	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1573	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1574	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1575
1576	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1577	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1578	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1579	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1580	raw_inode->i_frag = ei->i_frag_no;
1581	raw_inode->i_fsize = ei->i_frag_size;
1582	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1583	if (!S_ISREG(inode->i_mode))
1584		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1585	else {
1586		raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1587		if (inode->i_size > 0x7fffffffULL) {
1588			if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1589					EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1590			    EXT2_SB(sb)->s_es->s_rev_level ==
1591					cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1592			       /* If this is the first large file
1593				* created, add a flag to the superblock.
1594				*/
1595				spin_lock(&EXT2_SB(sb)->s_lock);
1596				ext2_update_dynamic_rev(sb);
1597				EXT2_SET_RO_COMPAT_FEATURE(sb,
1598					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1599				spin_unlock(&EXT2_SB(sb)->s_lock);
1600				ext2_sync_super(sb, EXT2_SB(sb)->s_es, 1);
1601			}
1602		}
1603	}
1604	
1605	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1606	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1607		if (old_valid_dev(inode->i_rdev)) {
1608			raw_inode->i_block[0] =
1609				cpu_to_le32(old_encode_dev(inode->i_rdev));
1610			raw_inode->i_block[1] = 0;
1611		} else {
1612			raw_inode->i_block[0] = 0;
1613			raw_inode->i_block[1] =
1614				cpu_to_le32(new_encode_dev(inode->i_rdev));
1615			raw_inode->i_block[2] = 0;
1616		}
1617	} else for (n = 0; n < EXT2_N_BLOCKS; n++)
1618		raw_inode->i_block[n] = ei->i_data[n];
1619	mark_buffer_dirty(bh);
1620	if (do_sync) {
1621		sync_dirty_buffer(bh);
1622		if (buffer_req(bh) && !buffer_uptodate(bh)) {
1623			printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1624				sb->s_id, (unsigned long) ino);
1625			err = -EIO;
1626		}
1627	}
1628	ei->i_state &= ~EXT2_STATE_NEW;
1629	brelse (bh);
1630	return err;
1631}
1632
1633int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1634{
1635	return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1636}
1637
1638int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1639{
1640	struct inode *inode = d_inode(dentry);
1641	int error;
1642
1643	error = setattr_prepare(dentry, iattr);
1644	if (error)
1645		return error;
1646
1647	if (is_quota_modification(inode, iattr)) {
1648		error = dquot_initialize(inode);
1649		if (error)
1650			return error;
1651	}
1652	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1653	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1654		error = dquot_transfer(inode, iattr);
1655		if (error)
1656			return error;
1657	}
1658	if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1659		error = ext2_setsize(inode, iattr->ia_size);
1660		if (error)
1661			return error;
1662	}
1663	setattr_copy(inode, iattr);
1664	if (iattr->ia_valid & ATTR_MODE)
1665		error = posix_acl_chmod(inode, inode->i_mode);
1666	mark_inode_dirty(inode);
1667
1668	return error;
1669}