1/*
   2 *  linux/fs/ext2/inode.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  from
  10 *
  11 *  linux/fs/minix/inode.c
  12 *
  13 *  Copyright (C) 1991, 1992  Linus Torvalds
  14 *
  15 *  Goal-directed block allocation by Stephen Tweedie
  16 * 	(sct@dcs.ed.ac.uk), 1993, 1998
  17 *  Big-endian to little-endian byte-swapping/bitmaps by
  18 *        David S. Miller (davem@caip.rutgers.edu), 1995
  19 *  64-bit file support on 64-bit platforms by Jakub Jelinek
  20 * 	(jj@sunsite.ms.mff.cuni.cz)
  21 *
  22 *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
  23 */
  24
  25#include <linux/time.h>
  26#include <linux/highuid.h>
  27#include <linux/pagemap.h>
  28#include <linux/dax.h>
  29#include <linux/quotaops.h>
 
  30#include <linux/writeback.h>
  31#include <linux/buffer_head.h>
  32#include <linux/mpage.h>
  33#include <linux/fiemap.h>
  34#include <linux/namei.h>
  35#include <linux/uio.h>
  36#include "ext2.h"
  37#include "acl.h"
  38#include "xattr.h"
 
 
 
 
  39
  40static int __ext2_write_inode(struct inode *inode, int do_sync);
  41
  42/*
  43 * Test whether an inode is a fast symlink.
  44 */
  45static inline int ext2_inode_is_fast_symlink(struct inode *inode)
  46{
  47	int ea_blocks = EXT2_I(inode)->i_file_acl ?
  48		(inode->i_sb->s_blocksize >> 9) : 0;
  49
  50	return (S_ISLNK(inode->i_mode) &&
  51		inode->i_blocks - ea_blocks == 0);
  52}
  53
  54static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
  55
  56static void ext2_write_failed(struct address_space *mapping, loff_t to)
  57{
  58	struct inode *inode = mapping->host;
  59
  60	if (to > inode->i_size) {
  61		truncate_pagecache(inode, inode->i_size);
  62		ext2_truncate_blocks(inode, inode->i_size);
  63	}
  64}
  65
  66/*
  67 * Called at the last iput() if i_nlink is zero.
  68 */
  69void ext2_evict_inode(struct inode * inode)
  70{
  71	struct ext2_block_alloc_info *rsv;
  72	int want_delete = 0;
  73
  74	if (!inode->i_nlink && !is_bad_inode(inode)) {
  75		want_delete = 1;
  76		dquot_initialize(inode);
  77	} else {
  78		dquot_drop(inode);
  79	}
  80
  81	truncate_inode_pages_final(&inode->i_data);
  82
  83	if (want_delete) {
  84		sb_start_intwrite(inode->i_sb);
  85		/* set dtime */
  86		EXT2_I(inode)->i_dtime	= get_seconds();
  87		mark_inode_dirty(inode);
  88		__ext2_write_inode(inode, inode_needs_sync(inode));
  89		/* truncate to 0 */
  90		inode->i_size = 0;
  91		if (inode->i_blocks)
  92			ext2_truncate_blocks(inode, 0);
  93		ext2_xattr_delete_inode(inode);
  94	}
  95
  96	invalidate_inode_buffers(inode);
  97	clear_inode(inode);
  98
  99	ext2_discard_reservation(inode);
 100	rsv = EXT2_I(inode)->i_block_alloc_info;
 101	EXT2_I(inode)->i_block_alloc_info = NULL;
 102	if (unlikely(rsv))
 103		kfree(rsv);
 104
 105	if (want_delete) {
 106		ext2_free_inode(inode);
 107		sb_end_intwrite(inode->i_sb);
 108	}
 109}
 110
 111typedef struct {
 112	__le32	*p;
 113	__le32	key;
 114	struct buffer_head *bh;
 115} Indirect;
 116
 117static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
 118{
 119	p->key = *(p->p = v);
 120	p->bh = bh;
 121}
 122
 123static inline int verify_chain(Indirect *from, Indirect *to)
 124{
 125	while (from <= to && from->key == *from->p)
 126		from++;
 127	return (from > to);
 128}
 129
 130/**
 131 *	ext2_block_to_path - parse the block number into array of offsets
 132 *	@inode: inode in question (we are only interested in its superblock)
 133 *	@i_block: block number to be parsed
 134 *	@offsets: array to store the offsets in
 135 *      @boundary: set this non-zero if the referred-to block is likely to be
 136 *             followed (on disk) by an indirect block.
 137 *	To store the locations of file's data ext2 uses a data structure common
 138 *	for UNIX filesystems - tree of pointers anchored in the inode, with
 139 *	data blocks at leaves and indirect blocks in intermediate nodes.
 140 *	This function translates the block number into path in that tree -
 141 *	return value is the path length and @offsets[n] is the offset of
 142 *	pointer to (n+1)th node in the nth one. If @block is out of range
 143 *	(negative or too large) warning is printed and zero returned.
 144 *
 145 *	Note: function doesn't find node addresses, so no IO is needed. All
 146 *	we need to know is the capacity of indirect blocks (taken from the
 147 *	inode->i_sb).
 148 */
 149
 150/*
 151 * Portability note: the last comparison (check that we fit into triple
 152 * indirect block) is spelled differently, because otherwise on an
 153 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 154 * if our filesystem had 8Kb blocks. We might use long long, but that would
 155 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 156 * i_block would have to be negative in the very beginning, so we would not
 157 * get there at all.
 158 */
 159
 160static int ext2_block_to_path(struct inode *inode,
 161			long i_block, int offsets[4], int *boundary)
 162{
 163	int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
 164	int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
 165	const long direct_blocks = EXT2_NDIR_BLOCKS,
 166		indirect_blocks = ptrs,
 167		double_blocks = (1 << (ptrs_bits * 2));
 168	int n = 0;
 169	int final = 0;
 170
 171	if (i_block < 0) {
 172		ext2_msg(inode->i_sb, KERN_WARNING,
 173			"warning: %s: block < 0", __func__);
 174	} else if (i_block < direct_blocks) {
 175		offsets[n++] = i_block;
 176		final = direct_blocks;
 177	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
 178		offsets[n++] = EXT2_IND_BLOCK;
 179		offsets[n++] = i_block;
 180		final = ptrs;
 181	} else if ((i_block -= indirect_blocks) < double_blocks) {
 182		offsets[n++] = EXT2_DIND_BLOCK;
 183		offsets[n++] = i_block >> ptrs_bits;
 184		offsets[n++] = i_block & (ptrs - 1);
 185		final = ptrs;
 186	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
 187		offsets[n++] = EXT2_TIND_BLOCK;
 188		offsets[n++] = i_block >> (ptrs_bits * 2);
 189		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
 190		offsets[n++] = i_block & (ptrs - 1);
 191		final = ptrs;
 192	} else {
 193		ext2_msg(inode->i_sb, KERN_WARNING,
 194			"warning: %s: block is too big", __func__);
 195	}
 196	if (boundary)
 197		*boundary = final - 1 - (i_block & (ptrs - 1));
 198
 199	return n;
 200}
 201
 202/**
 203 *	ext2_get_branch - read the chain of indirect blocks leading to data
 204 *	@inode: inode in question
 205 *	@depth: depth of the chain (1 - direct pointer, etc.)
 206 *	@offsets: offsets of pointers in inode/indirect blocks
 207 *	@chain: place to store the result
 208 *	@err: here we store the error value
 209 *
 210 *	Function fills the array of triples <key, p, bh> and returns %NULL
 211 *	if everything went OK or the pointer to the last filled triple
 212 *	(incomplete one) otherwise. Upon the return chain[i].key contains
 213 *	the number of (i+1)-th block in the chain (as it is stored in memory,
 214 *	i.e. little-endian 32-bit), chain[i].p contains the address of that
 215 *	number (it points into struct inode for i==0 and into the bh->b_data
 216 *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 217 *	block for i>0 and NULL for i==0. In other words, it holds the block
 218 *	numbers of the chain, addresses they were taken from (and where we can
 219 *	verify that chain did not change) and buffer_heads hosting these
 220 *	numbers.
 221 *
 222 *	Function stops when it stumbles upon zero pointer (absent block)
 223 *		(pointer to last triple returned, *@err == 0)
 224 *	or when it gets an IO error reading an indirect block
 225 *		(ditto, *@err == -EIO)
 226 *	or when it notices that chain had been changed while it was reading
 227 *		(ditto, *@err == -EAGAIN)
 228 *	or when it reads all @depth-1 indirect blocks successfully and finds
 229 *	the whole chain, all way to the data (returns %NULL, *err == 0).
 230 */
 231static Indirect *ext2_get_branch(struct inode *inode,
 232				 int depth,
 233				 int *offsets,
 234				 Indirect chain[4],
 235				 int *err)
 236{
 237	struct super_block *sb = inode->i_sb;
 238	Indirect *p = chain;
 239	struct buffer_head *bh;
 240
 241	*err = 0;
 242	/* i_data is not going away, no lock needed */
 243	add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
 244	if (!p->key)
 245		goto no_block;
 246	while (--depth) {
 247		bh = sb_bread(sb, le32_to_cpu(p->key));
 248		if (!bh)
 249			goto failure;
 250		read_lock(&EXT2_I(inode)->i_meta_lock);
 251		if (!verify_chain(chain, p))
 252			goto changed;
 253		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
 254		read_unlock(&EXT2_I(inode)->i_meta_lock);
 255		if (!p->key)
 256			goto no_block;
 257	}
 258	return NULL;
 259
 260changed:
 261	read_unlock(&EXT2_I(inode)->i_meta_lock);
 262	brelse(bh);
 263	*err = -EAGAIN;
 264	goto no_block;
 265failure:
 266	*err = -EIO;
 267no_block:
 268	return p;
 269}
 270
 271/**
 272 *	ext2_find_near - find a place for allocation with sufficient locality
 273 *	@inode: owner
 274 *	@ind: descriptor of indirect block.
 275 *
 276 *	This function returns the preferred place for block allocation.
 277 *	It is used when heuristic for sequential allocation fails.
 278 *	Rules are:
 279 *	  + if there is a block to the left of our position - allocate near it.
 280 *	  + if pointer will live in indirect block - allocate near that block.
 281 *	  + if pointer will live in inode - allocate in the same cylinder group.
 282 *
 283 * In the latter case we colour the starting block by the callers PID to
 284 * prevent it from clashing with concurrent allocations for a different inode
 285 * in the same block group.   The PID is used here so that functionally related
 286 * files will be close-by on-disk.
 287 *
 288 *	Caller must make sure that @ind is valid and will stay that way.
 289 */
 290
 291static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
 292{
 293	struct ext2_inode_info *ei = EXT2_I(inode);
 294	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
 295	__le32 *p;
 296	ext2_fsblk_t bg_start;
 297	ext2_fsblk_t colour;
 298
 299	/* Try to find previous block */
 300	for (p = ind->p - 1; p >= start; p--)
 301		if (*p)
 302			return le32_to_cpu(*p);
 303
 304	/* No such thing, so let's try location of indirect block */
 305	if (ind->bh)
 306		return ind->bh->b_blocknr;
 307
 308	/*
 309	 * It is going to be referred from inode itself? OK, just put it into
 310	 * the same cylinder group then.
 311	 */
 312	bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
 313	colour = (current->pid % 16) *
 314			(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 315	return bg_start + colour;
 316}
 317
 318/**
 319 *	ext2_find_goal - find a preferred place for allocation.
 320 *	@inode: owner
 321 *	@block:  block we want
 322 *	@partial: pointer to the last triple within a chain
 323 *
 324 *	Returns preferred place for a block (the goal).
 325 */
 326
 327static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
 328					  Indirect *partial)
 329{
 330	struct ext2_block_alloc_info *block_i;
 331
 332	block_i = EXT2_I(inode)->i_block_alloc_info;
 333
 334	/*
 335	 * try the heuristic for sequential allocation,
 336	 * failing that at least try to get decent locality.
 337	 */
 338	if (block_i && (block == block_i->last_alloc_logical_block + 1)
 339		&& (block_i->last_alloc_physical_block != 0)) {
 340		return block_i->last_alloc_physical_block + 1;
 341	}
 342
 343	return ext2_find_near(inode, partial);
 344}
 345
 346/**
 347 *	ext2_blks_to_allocate: Look up the block map and count the number
 348 *	of direct blocks need to be allocated for the given branch.
 349 *
 350 * 	@branch: chain of indirect blocks
 351 *	@k: number of blocks need for indirect blocks
 352 *	@blks: number of data blocks to be mapped.
 353 *	@blocks_to_boundary:  the offset in the indirect block
 354 *
 355 *	return the total number of blocks to be allocate, including the
 356 *	direct and indirect blocks.
 357 */
 358static int
 359ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
 360		int blocks_to_boundary)
 361{
 362	unsigned long count = 0;
 363
 364	/*
 365	 * Simple case, [t,d]Indirect block(s) has not allocated yet
 366	 * then it's clear blocks on that path have not allocated
 367	 */
 368	if (k > 0) {
 369		/* right now don't hanel cross boundary allocation */
 370		if (blks < blocks_to_boundary + 1)
 371			count += blks;
 372		else
 373			count += blocks_to_boundary + 1;
 374		return count;
 375	}
 376
 377	count++;
 378	while (count < blks && count <= blocks_to_boundary
 379		&& le32_to_cpu(*(branch[0].p + count)) == 0) {
 380		count++;
 381	}
 382	return count;
 383}
 384
 385/**
 386 *	ext2_alloc_blocks: multiple allocate blocks needed for a branch
 387 *	@indirect_blks: the number of blocks need to allocate for indirect
 388 *			blocks
 389 *
 390 *	@new_blocks: on return it will store the new block numbers for
 391 *	the indirect blocks(if needed) and the first direct block,
 392 *	@blks:	on return it will store the total number of allocated
 393 *		direct blocks
 394 */
 395static int ext2_alloc_blocks(struct inode *inode,
 396			ext2_fsblk_t goal, int indirect_blks, int blks,
 397			ext2_fsblk_t new_blocks[4], int *err)
 398{
 399	int target, i;
 400	unsigned long count = 0;
 401	int index = 0;
 402	ext2_fsblk_t current_block = 0;
 403	int ret = 0;
 404
 405	/*
 406	 * Here we try to allocate the requested multiple blocks at once,
 407	 * on a best-effort basis.
 408	 * To build a branch, we should allocate blocks for
 409	 * the indirect blocks(if not allocated yet), and at least
 410	 * the first direct block of this branch.  That's the
 411	 * minimum number of blocks need to allocate(required)
 412	 */
 413	target = blks + indirect_blks;
 414
 415	while (1) {
 416		count = target;
 417		/* allocating blocks for indirect blocks and direct blocks */
 418		current_block = ext2_new_blocks(inode,goal,&count,err);
 419		if (*err)
 420			goto failed_out;
 421
 422		target -= count;
 423		/* allocate blocks for indirect blocks */
 424		while (index < indirect_blks && count) {
 425			new_blocks[index++] = current_block++;
 426			count--;
 427		}
 428
 429		if (count > 0)
 430			break;
 431	}
 432
 433	/* save the new block number for the first direct block */
 434	new_blocks[index] = current_block;
 435
 436	/* total number of blocks allocated for direct blocks */
 437	ret = count;
 438	*err = 0;
 439	return ret;
 440failed_out:
 441	for (i = 0; i <index; i++)
 442		ext2_free_blocks(inode, new_blocks[i], 1);
 443	if (index)
 444		mark_inode_dirty(inode);
 445	return ret;
 446}
 447
 448/**
 449 *	ext2_alloc_branch - allocate and set up a chain of blocks.
 450 *	@inode: owner
 451 *	@num: depth of the chain (number of blocks to allocate)
 452 *	@offsets: offsets (in the blocks) to store the pointers to next.
 453 *	@branch: place to store the chain in.
 454 *
 455 *	This function allocates @num blocks, zeroes out all but the last one,
 456 *	links them into chain and (if we are synchronous) writes them to disk.
 457 *	In other words, it prepares a branch that can be spliced onto the
 458 *	inode. It stores the information about that chain in the branch[], in
 459 *	the same format as ext2_get_branch() would do. We are calling it after
 460 *	we had read the existing part of chain and partial points to the last
 461 *	triple of that (one with zero ->key). Upon the exit we have the same
 462 *	picture as after the successful ext2_get_block(), except that in one
 463 *	place chain is disconnected - *branch->p is still zero (we did not
 464 *	set the last link), but branch->key contains the number that should
 465 *	be placed into *branch->p to fill that gap.
 466 *
 467 *	If allocation fails we free all blocks we've allocated (and forget
 468 *	their buffer_heads) and return the error value the from failed
 469 *	ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
 470 *	as described above and return 0.
 471 */
 472
 473static int ext2_alloc_branch(struct inode *inode,
 474			int indirect_blks, int *blks, ext2_fsblk_t goal,
 475			int *offsets, Indirect *branch)
 476{
 477	int blocksize = inode->i_sb->s_blocksize;
 478	int i, n = 0;
 479	int err = 0;
 480	struct buffer_head *bh;
 481	int num;
 482	ext2_fsblk_t new_blocks[4];
 483	ext2_fsblk_t current_block;
 484
 485	num = ext2_alloc_blocks(inode, goal, indirect_blks,
 486				*blks, new_blocks, &err);
 487	if (err)
 488		return err;
 489
 490	branch[0].key = cpu_to_le32(new_blocks[0]);
 491	/*
 492	 * metadata blocks and data blocks are allocated.
 493	 */
 494	for (n = 1; n <= indirect_blks;  n++) {
 495		/*
 496		 * Get buffer_head for parent block, zero it out
 497		 * and set the pointer to new one, then send
 498		 * parent to disk.
 499		 */
 500		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 501		if (unlikely(!bh)) {
 502			err = -ENOMEM;
 503			goto failed;
 504		}
 505		branch[n].bh = bh;
 506		lock_buffer(bh);
 507		memset(bh->b_data, 0, blocksize);
 508		branch[n].p = (__le32 *) bh->b_data + offsets[n];
 509		branch[n].key = cpu_to_le32(new_blocks[n]);
 510		*branch[n].p = branch[n].key;
 511		if ( n == indirect_blks) {
 512			current_block = new_blocks[n];
 513			/*
 514			 * End of chain, update the last new metablock of
 515			 * the chain to point to the new allocated
 516			 * data blocks numbers
 517			 */
 518			for (i=1; i < num; i++)
 519				*(branch[n].p + i) = cpu_to_le32(++current_block);
 520		}
 521		set_buffer_uptodate(bh);
 522		unlock_buffer(bh);
 523		mark_buffer_dirty_inode(bh, inode);
 524		/* We used to sync bh here if IS_SYNC(inode).
 525		 * But we now rely upon generic_write_sync()
 526		 * and b_inode_buffers.  But not for directories.
 527		 */
 528		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
 529			sync_dirty_buffer(bh);
 530	}
 531	*blks = num;
 532	return err;
 533
 534failed:
 535	for (i = 1; i < n; i++)
 536		bforget(branch[i].bh);
 537	for (i = 0; i < indirect_blks; i++)
 538		ext2_free_blocks(inode, new_blocks[i], 1);
 539	ext2_free_blocks(inode, new_blocks[i], num);
 540	return err;
 541}
 542
 543/**
 544 * ext2_splice_branch - splice the allocated branch onto inode.
 545 * @inode: owner
 546 * @block: (logical) number of block we are adding
 547 * @where: location of missing link
 548 * @num:   number of indirect blocks we are adding
 549 * @blks:  number of direct blocks we are adding
 550 *
 551 * This function fills the missing link and does all housekeeping needed in
 552 * inode (->i_blocks, etc.). In case of success we end up with the full
 553 * chain to new block and return 0.
 554 */
 555static void ext2_splice_branch(struct inode *inode,
 556			long block, Indirect *where, int num, int blks)
 557{
 558	int i;
 559	struct ext2_block_alloc_info *block_i;
 560	ext2_fsblk_t current_block;
 561
 562	block_i = EXT2_I(inode)->i_block_alloc_info;
 563
 564	/* XXX LOCKING probably should have i_meta_lock ?*/
 565	/* That's it */
 566
 567	*where->p = where->key;
 568
 569	/*
 570	 * Update the host buffer_head or inode to point to more just allocated
 571	 * direct blocks blocks
 572	 */
 573	if (num == 0 && blks > 1) {
 574		current_block = le32_to_cpu(where->key) + 1;
 575		for (i = 1; i < blks; i++)
 576			*(where->p + i ) = cpu_to_le32(current_block++);
 577	}
 578
 579	/*
 580	 * update the most recently allocated logical & physical block
 581	 * in i_block_alloc_info, to assist find the proper goal block for next
 582	 * allocation
 583	 */
 584	if (block_i) {
 585		block_i->last_alloc_logical_block = block + blks - 1;
 586		block_i->last_alloc_physical_block =
 587				le32_to_cpu(where[num].key) + blks - 1;
 588	}
 589
 590	/* We are done with atomic stuff, now do the rest of housekeeping */
 591
 592	/* had we spliced it onto indirect block? */
 593	if (where->bh)
 594		mark_buffer_dirty_inode(where->bh, inode);
 595
 596	inode->i_ctime = CURRENT_TIME_SEC;
 597	mark_inode_dirty(inode);
 598}
 599
 600/*
 601 * Allocation strategy is simple: if we have to allocate something, we will
 602 * have to go the whole way to leaf. So let's do it before attaching anything
 603 * to tree, set linkage between the newborn blocks, write them if sync is
 604 * required, recheck the path, free and repeat if check fails, otherwise
 605 * set the last missing link (that will protect us from any truncate-generated
 606 * removals - all blocks on the path are immune now) and possibly force the
 607 * write on the parent block.
 608 * That has a nice additional property: no special recovery from the failed
 609 * allocations is needed - we simply release blocks and do not touch anything
 610 * reachable from inode.
 611 *
 612 * `handle' can be NULL if create == 0.
 613 *
 614 * return > 0, # of blocks mapped or allocated.
 615 * return = 0, if plain lookup failed.
 616 * return < 0, error case.
 617 */
 618static int ext2_get_blocks(struct inode *inode,
 619			   sector_t iblock, unsigned long maxblocks,
 620			   struct buffer_head *bh_result,
 621			   int create)
 622{
 623	int err = -EIO;
 624	int offsets[4];
 625	Indirect chain[4];
 626	Indirect *partial;
 627	ext2_fsblk_t goal;
 628	int indirect_blks;
 629	int blocks_to_boundary = 0;
 630	int depth;
 631	struct ext2_inode_info *ei = EXT2_I(inode);
 632	int count = 0;
 633	ext2_fsblk_t first_block = 0;
 634
 635	BUG_ON(maxblocks == 0);
 636
 637	depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
 638
 639	if (depth == 0)
 640		return (err);
 641
 642	partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 643	/* Simplest case - block found, no allocation needed */
 644	if (!partial) {
 645		first_block = le32_to_cpu(chain[depth - 1].key);
 646		clear_buffer_new(bh_result); /* What's this do? */
 647		count++;
 648		/*map more blocks*/
 649		while (count < maxblocks && count <= blocks_to_boundary) {
 650			ext2_fsblk_t blk;
 651
 652			if (!verify_chain(chain, chain + depth - 1)) {
 653				/*
 654				 * Indirect block might be removed by
 655				 * truncate while we were reading it.
 656				 * Handling of that case: forget what we've
 657				 * got now, go to reread.
 658				 */
 659				err = -EAGAIN;
 660				count = 0;
 661				break;
 662			}
 663			blk = le32_to_cpu(*(chain[depth-1].p + count));
 664			if (blk == first_block + count)
 665				count++;
 666			else
 667				break;
 668		}
 669		if (err != -EAGAIN)
 670			goto got_it;
 671	}
 672
 673	/* Next simple case - plain lookup or failed read of indirect block */
 674	if (!create || err == -EIO)
 675		goto cleanup;
 676
 677	mutex_lock(&ei->truncate_mutex);
 678	/*
 679	 * If the indirect block is missing while we are reading
 680	 * the chain(ext2_get_branch() returns -EAGAIN err), or
 681	 * if the chain has been changed after we grab the semaphore,
 682	 * (either because another process truncated this branch, or
 683	 * another get_block allocated this branch) re-grab the chain to see if
 684	 * the request block has been allocated or not.
 685	 *
 686	 * Since we already block the truncate/other get_block
 687	 * at this point, we will have the current copy of the chain when we
 688	 * splice the branch into the tree.
 689	 */
 690	if (err == -EAGAIN || !verify_chain(chain, partial)) {
 691		while (partial > chain) {
 692			brelse(partial->bh);
 693			partial--;
 694		}
 695		partial = ext2_get_branch(inode, depth, offsets, chain, &err);
 696		if (!partial) {
 697			count++;
 698			mutex_unlock(&ei->truncate_mutex);
 699			if (err)
 700				goto cleanup;
 701			clear_buffer_new(bh_result);
 702			goto got_it;
 703		}
 704	}
 705
 706	/*
 707	 * Okay, we need to do block allocation.  Lazily initialize the block
 708	 * allocation info here if necessary
 709	*/
 710	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
 711		ext2_init_block_alloc_info(inode);
 712
 713	goal = ext2_find_goal(inode, iblock, partial);
 714
 715	/* the number of blocks need to allocate for [d,t]indirect blocks */
 716	indirect_blks = (chain + depth) - partial - 1;
 717	/*
 718	 * Next look up the indirect map to count the totoal number of
 719	 * direct blocks to allocate for this branch.
 720	 */
 721	count = ext2_blks_to_allocate(partial, indirect_blks,
 722					maxblocks, blocks_to_boundary);
 723	/*
 724	 * XXX ???? Block out ext2_truncate while we alter the tree
 725	 */
 726	err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
 727				offsets + (partial - chain), partial);
 728
 729	if (err) {
 730		mutex_unlock(&ei->truncate_mutex);
 731		goto cleanup;
 732	}
 733
 734	if (IS_DAX(inode)) {
 735		/*
 736		 * block must be initialised before we put it in the tree
 737		 * so that it's not found by another thread before it's
 738		 * initialised
 739		 */
 740		err = dax_clear_sectors(inode->i_sb->s_bdev,
 741				le32_to_cpu(chain[depth-1].key) <<
 742				(inode->i_blkbits - 9),
 743				1 << inode->i_blkbits);
 744		if (err) {
 745			mutex_unlock(&ei->truncate_mutex);
 746			goto cleanup;
 747		}
 748	}
 749
 750	ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
 751	mutex_unlock(&ei->truncate_mutex);
 752	set_buffer_new(bh_result);
 753got_it:
 754	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
 755	if (count > blocks_to_boundary)
 756		set_buffer_boundary(bh_result);
 757	err = count;
 758	/* Clean up and exit */
 759	partial = chain + depth - 1;	/* the whole chain */
 760cleanup:
 761	while (partial > chain) {
 762		brelse(partial->bh);
 763		partial--;
 764	}
 765	return err;
 766}
 767
 768int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
 769{
 770	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
 771	int ret = ext2_get_blocks(inode, iblock, max_blocks,
 772			      bh_result, create);
 773	if (ret > 0) {
 774		bh_result->b_size = (ret << inode->i_blkbits);
 775		ret = 0;
 776	}
 777	return ret;
 778
 779}
 780
 781int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 782		u64 start, u64 len)
 783{
 784	return generic_block_fiemap(inode, fieinfo, start, len,
 785				    ext2_get_block);
 786}
 787
 788static int ext2_writepage(struct page *page, struct writeback_control *wbc)
 789{
 790	return block_write_full_page(page, ext2_get_block, wbc);
 791}
 792
 793static int ext2_readpage(struct file *file, struct page *page)
 794{
 795	return mpage_readpage(page, ext2_get_block);
 796}
 797
 798static int
 799ext2_readpages(struct file *file, struct address_space *mapping,
 800		struct list_head *pages, unsigned nr_pages)
 801{
 802	return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
 803}
 804
 805static int
 806ext2_write_begin(struct file *file, struct address_space *mapping,
 807		loff_t pos, unsigned len, unsigned flags,
 808		struct page **pagep, void **fsdata)
 809{
 810	int ret;
 811
 812	ret = block_write_begin(mapping, pos, len, flags, pagep,
 813				ext2_get_block);
 814	if (ret < 0)
 815		ext2_write_failed(mapping, pos + len);
 816	return ret;
 817}
 818
 819static int ext2_write_end(struct file *file, struct address_space *mapping,
 820			loff_t pos, unsigned len, unsigned copied,
 821			struct page *page, void *fsdata)
 822{
 823	int ret;
 824
 825	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
 826	if (ret < len)
 827		ext2_write_failed(mapping, pos + len);
 828	return ret;
 829}
 830
 831static int
 832ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
 833		loff_t pos, unsigned len, unsigned flags,
 834		struct page **pagep, void **fsdata)
 835{
 836	int ret;
 837
 838	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
 839			       ext2_get_block);
 840	if (ret < 0)
 841		ext2_write_failed(mapping, pos + len);
 842	return ret;
 843}
 844
 845static int ext2_nobh_writepage(struct page *page,
 846			struct writeback_control *wbc)
 847{
 848	return nobh_writepage(page, ext2_get_block, wbc);
 849}
 850
 851static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 852{
 853	return generic_block_bmap(mapping,block,ext2_get_block);
 854}
 855
 856static ssize_t
 857ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 
 858{
 859	struct file *file = iocb->ki_filp;
 860	struct address_space *mapping = file->f_mapping;
 861	struct inode *inode = mapping->host;
 862	size_t count = iov_iter_count(iter);
 863	ssize_t ret;
 864
 865	if (IS_DAX(inode))
 866		ret = dax_do_io(iocb, inode, iter, offset, ext2_get_block, NULL,
 867				DIO_LOCKING);
 868	else
 869		ret = blockdev_direct_IO(iocb, inode, iter, offset,
 870					 ext2_get_block);
 871	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 872		ext2_write_failed(mapping, offset + count);
 873	return ret;
 874}
 875
 876static int
 877ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
 878{
 879#ifdef CONFIG_FS_DAX
 880	if (dax_mapping(mapping)) {
 881		return dax_writeback_mapping_range(mapping,
 882						   mapping->host->i_sb->s_bdev,
 883						   wbc);
 884	}
 885#endif
 886
 887	return mpage_writepages(mapping, wbc, ext2_get_block);
 888}
 889
 890const struct address_space_operations ext2_aops = {
 891	.readpage		= ext2_readpage,
 892	.readpages		= ext2_readpages,
 893	.writepage		= ext2_writepage,
 894	.write_begin		= ext2_write_begin,
 895	.write_end		= ext2_write_end,
 896	.bmap			= ext2_bmap,
 897	.direct_IO		= ext2_direct_IO,
 898	.writepages		= ext2_writepages,
 899	.migratepage		= buffer_migrate_page,
 900	.is_partially_uptodate	= block_is_partially_uptodate,
 901	.error_remove_page	= generic_error_remove_page,
 902};
 903
 
 
 
 
 
 904const struct address_space_operations ext2_nobh_aops = {
 905	.readpage		= ext2_readpage,
 906	.readpages		= ext2_readpages,
 907	.writepage		= ext2_nobh_writepage,
 908	.write_begin		= ext2_nobh_write_begin,
 909	.write_end		= nobh_write_end,
 910	.bmap			= ext2_bmap,
 911	.direct_IO		= ext2_direct_IO,
 912	.writepages		= ext2_writepages,
 913	.migratepage		= buffer_migrate_page,
 914	.error_remove_page	= generic_error_remove_page,
 915};
 916
 917/*
 918 * Probably it should be a library function... search for first non-zero word
 919 * or memcmp with zero_page, whatever is better for particular architecture.
 920 * Linus?
 921 */
 922static inline int all_zeroes(__le32 *p, __le32 *q)
 923{
 924	while (p < q)
 925		if (*p++)
 926			return 0;
 927	return 1;
 928}
 929
 930/**
 931 *	ext2_find_shared - find the indirect blocks for partial truncation.
 932 *	@inode:	  inode in question
 933 *	@depth:	  depth of the affected branch
 934 *	@offsets: offsets of pointers in that branch (see ext2_block_to_path)
 935 *	@chain:	  place to store the pointers to partial indirect blocks
 936 *	@top:	  place to the (detached) top of branch
 937 *
 938 *	This is a helper function used by ext2_truncate().
 939 *
 940 *	When we do truncate() we may have to clean the ends of several indirect
 941 *	blocks but leave the blocks themselves alive. Block is partially
 942 *	truncated if some data below the new i_size is referred from it (and
 943 *	it is on the path to the first completely truncated data block, indeed).
 944 *	We have to free the top of that path along with everything to the right
 945 *	of the path. Since no allocation past the truncation point is possible
 946 *	until ext2_truncate() finishes, we may safely do the latter, but top
 947 *	of branch may require special attention - pageout below the truncation
 948 *	point might try to populate it.
 949 *
 950 *	We atomically detach the top of branch from the tree, store the block
 951 *	number of its root in *@top, pointers to buffer_heads of partially
 952 *	truncated blocks - in @chain[].bh and pointers to their last elements
 953 *	that should not be removed - in @chain[].p. Return value is the pointer
 954 *	to last filled element of @chain.
 955 *
 956 *	The work left to caller to do the actual freeing of subtrees:
 957 *		a) free the subtree starting from *@top
 958 *		b) free the subtrees whose roots are stored in
 959 *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
 960 *		c) free the subtrees growing from the inode past the @chain[0].p
 961 *			(no partially truncated stuff there).
 962 */
 963
 964static Indirect *ext2_find_shared(struct inode *inode,
 965				int depth,
 966				int offsets[4],
 967				Indirect chain[4],
 968				__le32 *top)
 969{
 970	Indirect *partial, *p;
 971	int k, err;
 972
 973	*top = 0;
 974	for (k = depth; k > 1 && !offsets[k-1]; k--)
 975		;
 976	partial = ext2_get_branch(inode, k, offsets, chain, &err);
 977	if (!partial)
 978		partial = chain + k-1;
 979	/*
 980	 * If the branch acquired continuation since we've looked at it -
 981	 * fine, it should all survive and (new) top doesn't belong to us.
 982	 */
 983	write_lock(&EXT2_I(inode)->i_meta_lock);
 984	if (!partial->key && *partial->p) {
 985		write_unlock(&EXT2_I(inode)->i_meta_lock);
 986		goto no_top;
 987	}
 988	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
 989		;
 990	/*
 991	 * OK, we've found the last block that must survive. The rest of our
 992	 * branch should be detached before unlocking. However, if that rest
 993	 * of branch is all ours and does not grow immediately from the inode
 994	 * it's easier to cheat and just decrement partial->p.
 995	 */
 996	if (p == chain + k - 1 && p > chain) {
 997		p->p--;
 998	} else {
 999		*top = *p->p;
1000		*p->p = 0;
1001	}
1002	write_unlock(&EXT2_I(inode)->i_meta_lock);
1003
1004	while(partial > p)
1005	{
1006		brelse(partial->bh);
1007		partial--;
1008	}
1009no_top:
1010	return partial;
1011}
1012
1013/**
1014 *	ext2_free_data - free a list of data blocks
1015 *	@inode:	inode we are dealing with
1016 *	@p:	array of block numbers
1017 *	@q:	points immediately past the end of array
1018 *
1019 *	We are freeing all blocks referred from that array (numbers are
1020 *	stored as little-endian 32-bit) and updating @inode->i_blocks
1021 *	appropriately.
1022 */
1023static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1024{
1025	unsigned long block_to_free = 0, count = 0;
1026	unsigned long nr;
1027
1028	for ( ; p < q ; p++) {
1029		nr = le32_to_cpu(*p);
1030		if (nr) {
1031			*p = 0;
1032			/* accumulate blocks to free if they're contiguous */
1033			if (count == 0)
1034				goto free_this;
1035			else if (block_to_free == nr - count)
1036				count++;
1037			else {
1038				ext2_free_blocks (inode, block_to_free, count);
1039				mark_inode_dirty(inode);
1040			free_this:
1041				block_to_free = nr;
1042				count = 1;
1043			}
1044		}
1045	}
1046	if (count > 0) {
1047		ext2_free_blocks (inode, block_to_free, count);
1048		mark_inode_dirty(inode);
1049	}
1050}
1051
1052/**
1053 *	ext2_free_branches - free an array of branches
1054 *	@inode:	inode we are dealing with
1055 *	@p:	array of block numbers
1056 *	@q:	pointer immediately past the end of array
1057 *	@depth:	depth of the branches to free
1058 *
1059 *	We are freeing all blocks referred from these branches (numbers are
1060 *	stored as little-endian 32-bit) and updating @inode->i_blocks
1061 *	appropriately.
1062 */
1063static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1064{
1065	struct buffer_head * bh;
1066	unsigned long nr;
1067
1068	if (depth--) {
1069		int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1070		for ( ; p < q ; p++) {
1071			nr = le32_to_cpu(*p);
1072			if (!nr)
1073				continue;
1074			*p = 0;
1075			bh = sb_bread(inode->i_sb, nr);
1076			/*
1077			 * A read failure? Report error and clear slot
1078			 * (should be rare).
1079			 */ 
1080			if (!bh) {
1081				ext2_error(inode->i_sb, "ext2_free_branches",
1082					"Read failure, inode=%ld, block=%ld",
1083					inode->i_ino, nr);
1084				continue;
1085			}
1086			ext2_free_branches(inode,
1087					   (__le32*)bh->b_data,
1088					   (__le32*)bh->b_data + addr_per_block,
1089					   depth);
1090			bforget(bh);
1091			ext2_free_blocks(inode, nr, 1);
1092			mark_inode_dirty(inode);
1093		}
1094	} else
1095		ext2_free_data(inode, p, q);
1096}
1097
1098/* dax_sem must be held when calling this function */
1099static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1100{
1101	__le32 *i_data = EXT2_I(inode)->i_data;
1102	struct ext2_inode_info *ei = EXT2_I(inode);
1103	int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1104	int offsets[4];
1105	Indirect chain[4];
1106	Indirect *partial;
1107	__le32 nr = 0;
1108	int n;
1109	long iblock;
1110	unsigned blocksize;
1111	blocksize = inode->i_sb->s_blocksize;
1112	iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1113
1114#ifdef CONFIG_FS_DAX
1115	WARN_ON(!rwsem_is_locked(&ei->dax_sem));
1116#endif
1117
1118	n = ext2_block_to_path(inode, iblock, offsets, NULL);
1119	if (n == 0)
1120		return;
1121
1122	/*
1123	 * From here we block out all ext2_get_block() callers who want to
1124	 * modify the block allocation tree.
1125	 */
1126	mutex_lock(&ei->truncate_mutex);
1127
1128	if (n == 1) {
1129		ext2_free_data(inode, i_data+offsets[0],
1130					i_data + EXT2_NDIR_BLOCKS);
1131		goto do_indirects;
1132	}
1133
1134	partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1135	/* Kill the top of shared branch (already detached) */
1136	if (nr) {
1137		if (partial == chain)
1138			mark_inode_dirty(inode);
1139		else
1140			mark_buffer_dirty_inode(partial->bh, inode);
1141		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1142	}
1143	/* Clear the ends of indirect blocks on the shared branch */
1144	while (partial > chain) {
1145		ext2_free_branches(inode,
1146				   partial->p + 1,
1147				   (__le32*)partial->bh->b_data+addr_per_block,
1148				   (chain+n-1) - partial);
1149		mark_buffer_dirty_inode(partial->bh, inode);
1150		brelse (partial->bh);
1151		partial--;
1152	}
1153do_indirects:
1154	/* Kill the remaining (whole) subtrees */
1155	switch (offsets[0]) {
1156		default:
1157			nr = i_data[EXT2_IND_BLOCK];
1158			if (nr) {
1159				i_data[EXT2_IND_BLOCK] = 0;
1160				mark_inode_dirty(inode);
1161				ext2_free_branches(inode, &nr, &nr+1, 1);
1162			}
1163		case EXT2_IND_BLOCK:
1164			nr = i_data[EXT2_DIND_BLOCK];
1165			if (nr) {
1166				i_data[EXT2_DIND_BLOCK] = 0;
1167				mark_inode_dirty(inode);
1168				ext2_free_branches(inode, &nr, &nr+1, 2);
1169			}
1170		case EXT2_DIND_BLOCK:
1171			nr = i_data[EXT2_TIND_BLOCK];
1172			if (nr) {
1173				i_data[EXT2_TIND_BLOCK] = 0;
1174				mark_inode_dirty(inode);
1175				ext2_free_branches(inode, &nr, &nr+1, 3);
1176			}
1177		case EXT2_TIND_BLOCK:
1178			;
1179	}
1180
1181	ext2_discard_reservation(inode);
1182
1183	mutex_unlock(&ei->truncate_mutex);
1184}
1185
1186static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1187{
1188	/*
1189	 * XXX: it seems like a bug here that we don't allow
1190	 * IS_APPEND inode to have blocks-past-i_size trimmed off.
1191	 * review and fix this.
1192	 *
1193	 * Also would be nice to be able to handle IO errors and such,
1194	 * but that's probably too much to ask.
1195	 */
1196	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1197	    S_ISLNK(inode->i_mode)))
1198		return;
1199	if (ext2_inode_is_fast_symlink(inode))
1200		return;
1201	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1202		return;
1203
1204	dax_sem_down_write(EXT2_I(inode));
1205	__ext2_truncate_blocks(inode, offset);
1206	dax_sem_up_write(EXT2_I(inode));
1207}
1208
1209static int ext2_setsize(struct inode *inode, loff_t newsize)
1210{
1211	int error;
1212
1213	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1214	    S_ISLNK(inode->i_mode)))
1215		return -EINVAL;
1216	if (ext2_inode_is_fast_symlink(inode))
1217		return -EINVAL;
1218	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1219		return -EPERM;
1220
1221	inode_dio_wait(inode);
1222
1223	if (IS_DAX(inode))
1224		error = dax_truncate_page(inode, newsize, ext2_get_block);
1225	else if (test_opt(inode->i_sb, NOBH))
1226		error = nobh_truncate_page(inode->i_mapping,
1227				newsize, ext2_get_block);
1228	else
1229		error = block_truncate_page(inode->i_mapping,
1230				newsize, ext2_get_block);
1231	if (error)
1232		return error;
1233
1234	dax_sem_down_write(EXT2_I(inode));
1235	truncate_setsize(inode, newsize);
1236	__ext2_truncate_blocks(inode, newsize);
1237	dax_sem_up_write(EXT2_I(inode));
1238
1239	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1240	if (inode_needs_sync(inode)) {
1241		sync_mapping_buffers(inode->i_mapping);
1242		sync_inode_metadata(inode, 1);
1243	} else {
1244		mark_inode_dirty(inode);
1245	}
1246
1247	return 0;
1248}
1249
1250static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1251					struct buffer_head **p)
1252{
1253	struct buffer_head * bh;
1254	unsigned long block_group;
1255	unsigned long block;
1256	unsigned long offset;
1257	struct ext2_group_desc * gdp;
1258
1259	*p = NULL;
1260	if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1261	    ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1262		goto Einval;
1263
1264	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1265	gdp = ext2_get_group_desc(sb, block_group, NULL);
1266	if (!gdp)
1267		goto Egdp;
1268	/*
1269	 * Figure out the offset within the block group inode table
1270	 */
1271	offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1272	block = le32_to_cpu(gdp->bg_inode_table) +
1273		(offset >> EXT2_BLOCK_SIZE_BITS(sb));
1274	if (!(bh = sb_bread(sb, block)))
1275		goto Eio;
1276
1277	*p = bh;
1278	offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1279	return (struct ext2_inode *) (bh->b_data + offset);
1280
1281Einval:
1282	ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1283		   (unsigned long) ino);
1284	return ERR_PTR(-EINVAL);
1285Eio:
1286	ext2_error(sb, "ext2_get_inode",
1287		   "unable to read inode block - inode=%lu, block=%lu",
1288		   (unsigned long) ino, block);
1289Egdp:
1290	return ERR_PTR(-EIO);
1291}
1292
1293void ext2_set_inode_flags(struct inode *inode)
1294{
1295	unsigned int flags = EXT2_I(inode)->i_flags;
1296
1297	inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1298				S_DIRSYNC | S_DAX);
1299	if (flags & EXT2_SYNC_FL)
1300		inode->i_flags |= S_SYNC;
1301	if (flags & EXT2_APPEND_FL)
1302		inode->i_flags |= S_APPEND;
1303	if (flags & EXT2_IMMUTABLE_FL)
1304		inode->i_flags |= S_IMMUTABLE;
1305	if (flags & EXT2_NOATIME_FL)
1306		inode->i_flags |= S_NOATIME;
1307	if (flags & EXT2_DIRSYNC_FL)
1308		inode->i_flags |= S_DIRSYNC;
1309	if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1310		inode->i_flags |= S_DAX;
1311}
1312
1313/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1314void ext2_get_inode_flags(struct ext2_inode_info *ei)
1315{
1316	unsigned int flags = ei->vfs_inode.i_flags;
1317
1318	ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1319			EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1320	if (flags & S_SYNC)
1321		ei->i_flags |= EXT2_SYNC_FL;
1322	if (flags & S_APPEND)
1323		ei->i_flags |= EXT2_APPEND_FL;
1324	if (flags & S_IMMUTABLE)
1325		ei->i_flags |= EXT2_IMMUTABLE_FL;
1326	if (flags & S_NOATIME)
1327		ei->i_flags |= EXT2_NOATIME_FL;
1328	if (flags & S_DIRSYNC)
1329		ei->i_flags |= EXT2_DIRSYNC_FL;
1330}
1331
1332struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1333{
1334	struct ext2_inode_info *ei;
1335	struct buffer_head * bh;
1336	struct ext2_inode *raw_inode;
1337	struct inode *inode;
1338	long ret = -EIO;
1339	int n;
1340	uid_t i_uid;
1341	gid_t i_gid;
1342
1343	inode = iget_locked(sb, ino);
1344	if (!inode)
1345		return ERR_PTR(-ENOMEM);
1346	if (!(inode->i_state & I_NEW))
1347		return inode;
1348
1349	ei = EXT2_I(inode);
1350	ei->i_block_alloc_info = NULL;
1351
1352	raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1353	if (IS_ERR(raw_inode)) {
1354		ret = PTR_ERR(raw_inode);
1355 		goto bad_inode;
1356	}
1357
1358	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1359	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1360	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1361	if (!(test_opt (inode->i_sb, NO_UID32))) {
1362		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1363		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1364	}
1365	i_uid_write(inode, i_uid);
1366	i_gid_write(inode, i_gid);
1367	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1368	inode->i_size = le32_to_cpu(raw_inode->i_size);
1369	inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1370	inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1371	inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1372	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1373	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1374	/* We now have enough fields to check if the inode was active or not.
1375	 * This is needed because nfsd might try to access dead inodes
1376	 * the test is that same one that e2fsck uses
1377	 * NeilBrown 1999oct15
1378	 */
1379	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1380		/* this inode is deleted */
1381		brelse (bh);
1382		ret = -ESTALE;
1383		goto bad_inode;
1384	}
1385	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1386	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1387	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1388	ei->i_frag_no = raw_inode->i_frag;
1389	ei->i_frag_size = raw_inode->i_fsize;
1390	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1391	ei->i_dir_acl = 0;
1392	if (S_ISREG(inode->i_mode))
1393		inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1394	else
1395		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1396	ei->i_dtime = 0;
1397	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1398	ei->i_state = 0;
1399	ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1400	ei->i_dir_start_lookup = 0;
1401
1402	/*
1403	 * NOTE! The in-memory inode i_data array is in little-endian order
1404	 * even on big-endian machines: we do NOT byteswap the block numbers!
1405	 */
1406	for (n = 0; n < EXT2_N_BLOCKS; n++)
1407		ei->i_data[n] = raw_inode->i_block[n];
1408
1409	if (S_ISREG(inode->i_mode)) {
1410		inode->i_op = &ext2_file_inode_operations;
1411		if (test_opt(inode->i_sb, NOBH)) {
 
 
 
1412			inode->i_mapping->a_ops = &ext2_nobh_aops;
1413			inode->i_fop = &ext2_file_operations;
1414		} else {
1415			inode->i_mapping->a_ops = &ext2_aops;
1416			inode->i_fop = &ext2_file_operations;
1417		}
1418	} else if (S_ISDIR(inode->i_mode)) {
1419		inode->i_op = &ext2_dir_inode_operations;
1420		inode->i_fop = &ext2_dir_operations;
1421		if (test_opt(inode->i_sb, NOBH))
1422			inode->i_mapping->a_ops = &ext2_nobh_aops;
1423		else
1424			inode->i_mapping->a_ops = &ext2_aops;
1425	} else if (S_ISLNK(inode->i_mode)) {
1426		if (ext2_inode_is_fast_symlink(inode)) {
1427			inode->i_link = (char *)ei->i_data;
1428			inode->i_op = &ext2_fast_symlink_inode_operations;
1429			nd_terminate_link(ei->i_data, inode->i_size,
1430				sizeof(ei->i_data) - 1);
1431		} else {
1432			inode->i_op = &ext2_symlink_inode_operations;
1433			inode_nohighmem(inode);
1434			if (test_opt(inode->i_sb, NOBH))
1435				inode->i_mapping->a_ops = &ext2_nobh_aops;
1436			else
1437				inode->i_mapping->a_ops = &ext2_aops;
1438		}
1439	} else {
1440		inode->i_op = &ext2_special_inode_operations;
1441		if (raw_inode->i_block[0])
1442			init_special_inode(inode, inode->i_mode,
1443			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1444		else 
1445			init_special_inode(inode, inode->i_mode,
1446			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1447	}
1448	brelse (bh);
1449	ext2_set_inode_flags(inode);
1450	unlock_new_inode(inode);
1451	return inode;
1452	
1453bad_inode:
1454	iget_failed(inode);
1455	return ERR_PTR(ret);
1456}
1457
1458static int __ext2_write_inode(struct inode *inode, int do_sync)
1459{
1460	struct ext2_inode_info *ei = EXT2_I(inode);
1461	struct super_block *sb = inode->i_sb;
1462	ino_t ino = inode->i_ino;
1463	uid_t uid = i_uid_read(inode);
1464	gid_t gid = i_gid_read(inode);
1465	struct buffer_head * bh;
1466	struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1467	int n;
1468	int err = 0;
1469
1470	if (IS_ERR(raw_inode))
1471 		return -EIO;
1472
1473	/* For fields not not tracking in the in-memory inode,
1474	 * initialise them to zero for new inodes. */
1475	if (ei->i_state & EXT2_STATE_NEW)
1476		memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1477
1478	ext2_get_inode_flags(ei);
1479	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1480	if (!(test_opt(sb, NO_UID32))) {
1481		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1482		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1483/*
1484 * Fix up interoperability with old kernels. Otherwise, old inodes get
1485 * re-used with the upper 16 bits of the uid/gid intact
1486 */
1487		if (!ei->i_dtime) {
1488			raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1489			raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1490		} else {
1491			raw_inode->i_uid_high = 0;
1492			raw_inode->i_gid_high = 0;
1493		}
1494	} else {
1495		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1496		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1497		raw_inode->i_uid_high = 0;
1498		raw_inode->i_gid_high = 0;
1499	}
1500	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1501	raw_inode->i_size = cpu_to_le32(inode->i_size);
1502	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1503	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1504	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1505
1506	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1507	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1508	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1509	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1510	raw_inode->i_frag = ei->i_frag_no;
1511	raw_inode->i_fsize = ei->i_frag_size;
1512	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1513	if (!S_ISREG(inode->i_mode))
1514		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1515	else {
1516		raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1517		if (inode->i_size > 0x7fffffffULL) {
1518			if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1519					EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1520			    EXT2_SB(sb)->s_es->s_rev_level ==
1521					cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1522			       /* If this is the first large file
1523				* created, add a flag to the superblock.
1524				*/
1525				spin_lock(&EXT2_SB(sb)->s_lock);
1526				ext2_update_dynamic_rev(sb);
1527				EXT2_SET_RO_COMPAT_FEATURE(sb,
1528					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1529				spin_unlock(&EXT2_SB(sb)->s_lock);
1530				ext2_write_super(sb);
1531			}
1532		}
1533	}
1534	
1535	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1536	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1537		if (old_valid_dev(inode->i_rdev)) {
1538			raw_inode->i_block[0] =
1539				cpu_to_le32(old_encode_dev(inode->i_rdev));
1540			raw_inode->i_block[1] = 0;
1541		} else {
1542			raw_inode->i_block[0] = 0;
1543			raw_inode->i_block[1] =
1544				cpu_to_le32(new_encode_dev(inode->i_rdev));
1545			raw_inode->i_block[2] = 0;
1546		}
1547	} else for (n = 0; n < EXT2_N_BLOCKS; n++)
1548		raw_inode->i_block[n] = ei->i_data[n];
1549	mark_buffer_dirty(bh);
1550	if (do_sync) {
1551		sync_dirty_buffer(bh);
1552		if (buffer_req(bh) && !buffer_uptodate(bh)) {
1553			printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1554				sb->s_id, (unsigned long) ino);
1555			err = -EIO;
1556		}
1557	}
1558	ei->i_state &= ~EXT2_STATE_NEW;
1559	brelse (bh);
1560	return err;
1561}
1562
1563int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1564{
1565	return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1566}
1567
1568int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1569{
1570	struct inode *inode = d_inode(dentry);
1571	int error;
1572
1573	error = inode_change_ok(inode, iattr);
1574	if (error)
1575		return error;
1576
1577	if (is_quota_modification(inode, iattr)) {
1578		error = dquot_initialize(inode);
1579		if (error)
1580			return error;
1581	}
1582	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1583	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1584		error = dquot_transfer(inode, iattr);
1585		if (error)
1586			return error;
1587	}
1588	if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1589		error = ext2_setsize(inode, iattr->ia_size);
1590		if (error)
1591			return error;
1592	}
1593	setattr_copy(inode, iattr);
1594	if (iattr->ia_valid & ATTR_MODE)
1595		error = posix_acl_chmod(inode, inode->i_mode);
1596	mark_inode_dirty(inode);
1597
1598	return error;
1599}