inode.c 96.4 KB
Newer Older
1
/*
2
 *  linux/fs/ext4/inode.c
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Goal-directed block allocation by Stephen Tweedie
 *	(sct@redhat.com), 1993, 1998
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 *  64-bit file support on 64-bit platforms by Jakub Jelinek
 *	(jj@sunsite.ms.mff.cuni.cz)
 *
22
 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
23 24 25 26 27
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
28 29
#include <linux/ext4_jbd2.h>
#include <linux/jbd2.h>
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include "xattr.h"
#include "acl.h"

/*
 * Test whether an inode is a fast symlink.
 */
45
static int ext4_inode_is_fast_symlink(struct inode *inode)
46
{
47
	int ea_blocks = EXT4_I(inode)->i_file_acl ?
48 49 50 51 52 53
		(inode->i_sb->s_blocksize >> 9) : 0;

	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}

/*
54
 * The ext4 forget function must perform a revoke if we are freeing data
55 56 57 58 59 60 61
 * which has been journaled.  Metadata (eg. indirect blocks) must be
 * revoked in all cases.
 *
 * "bh" may be NULL: a metadata block may have been freed from memory
 * but there may still be a record of it in the journal, and that record
 * still needs to be revoked.
 */
62 63
int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
			struct buffer_head *bh, ext4_fsblk_t blocknr)
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
{
	int err;

	might_sleep();

	BUFFER_TRACE(bh, "enter");

	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
		  "data mode %lx\n",
		  bh, is_metadata, inode->i_mode,
		  test_opt(inode->i_sb, DATA_FLAGS));

	/* Never use the revoke function if we are doing full data
	 * journaling: there is no need to, and a V1 superblock won't
	 * support it.  Otherwise, only skip the revoke on un-journaled
	 * data blocks. */

81 82
	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
	    (!is_metadata && !ext4_should_journal_data(inode))) {
83
		if (bh) {
84
			BUFFER_TRACE(bh, "call jbd2_journal_forget");
85
			return ext4_journal_forget(handle, bh);
86 87 88 89 90 91 92
		}
		return 0;
	}

	/*
	 * data!=journal && (is_metadata || should_journal_data(inode))
	 */
93 94
	BUFFER_TRACE(bh, "call ext4_journal_revoke");
	err = ext4_journal_revoke(handle, blocknr, bh);
95
	if (err)
96
		ext4_abort(inode->i_sb, __FUNCTION__,
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114
			   "error %d when attempting revoke", err);
	BUFFER_TRACE(bh, "exit");
	return err;
}

/*
 * Work out how many blocks we need to proceed with the next chunk of a
 * truncate transaction.
 */
static unsigned long blocks_for_truncate(struct inode *inode)
{
	unsigned long needed;

	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);

	/* Give ourselves just enough room to cope with inodes in which
	 * i_blocks is corrupt: we've seen disk corruptions in the past
	 * which resulted in random data in an inode which looked enough
115
	 * like a regular file for ext4 to try to delete it.  Things
116 117 118 119 120 121 122
	 * will go a bit crazy if that happens, but at least we should
	 * try not to panic the whole kernel. */
	if (needed < 2)
		needed = 2;

	/* But we need to bound the transaction so we don't overflow the
	 * journal. */
123 124
	if (needed > EXT4_MAX_TRANS_DATA)
		needed = EXT4_MAX_TRANS_DATA;
125

126
	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142
}

/*
 * Truncate transactions can be complex and absolutely huge.  So we need to
 * be able to restart the transaction at a conventient checkpoint to make
 * sure we don't overflow the journal.
 *
 * start_transaction gets us a new handle for a truncate transaction,
 * and extend_transaction tries to extend the existing one a bit.  If
 * extend fails, we need to propagate the failure up and restart the
 * transaction in the top-level truncate loop. --sct
 */
static handle_t *start_transaction(struct inode *inode)
{
	handle_t *result;

143
	result = ext4_journal_start(inode, blocks_for_truncate(inode));
144 145 146
	if (!IS_ERR(result))
		return result;

147
	ext4_std_error(inode->i_sb, PTR_ERR(result));
148 149 150 151 152 153 154 155 156 157 158
	return result;
}

/*
 * Try to extend this transaction for the purposes of truncation.
 *
 * Returns 0 if we managed to create more room.  If we can't create more
 * room, and the transaction must be restarted we return 1.
 */
static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
{
159
	if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
160
		return 0;
161
	if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
162 163 164 165 166 167 168 169 170
		return 0;
	return 1;
}

/*
 * Restart the transaction associated with *handle.  This does a commit,
 * so before we call here everything must be consistently dirtied against
 * this transaction.
 */
171
static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
172 173
{
	jbd_debug(2, "restarting handle %p\n", handle);
174
	return ext4_journal_restart(handle, blocks_for_truncate(inode));
175 176 177 178 179
}

/*
 * Called at the last iput() if i_nlink is zero.
 */
180
void ext4_delete_inode (struct inode * inode)
181 182 183 184 185 186 187 188 189 190 191 192 193 194 195
{
	handle_t *handle;

	truncate_inode_pages(&inode->i_data, 0);

	if (is_bad_inode(inode))
		goto no_delete;

	handle = start_transaction(inode);
	if (IS_ERR(handle)) {
		/*
		 * If we're going to skip the normal cleanup, we still need to
		 * make sure that the in-core orphan linked list is properly
		 * cleaned up.
		 */
196
		ext4_orphan_del(NULL, inode);
197 198 199 200 201 202 203
		goto no_delete;
	}

	if (IS_SYNC(inode))
		handle->h_sync = 1;
	inode->i_size = 0;
	if (inode->i_blocks)
204
		ext4_truncate(inode);
205
	/*
206
	 * Kill off the orphan record which ext4_truncate created.
207
	 * AKPM: I think this can be inside the above `if'.
208
	 * Note that ext4_orphan_del() has to be able to cope with the
209
	 * deletion of a non-existent orphan - this is because we don't
210
	 * know if ext4_truncate() actually created an orphan record.
211 212
	 * (Well, we could do this if we need to, but heck - it works)
	 */
213 214
	ext4_orphan_del(handle, inode);
	EXT4_I(inode)->i_dtime	= get_seconds();
215 216 217 218 219 220 221 222

	/*
	 * One subtle ordering requirement: if anything has gone wrong
	 * (transaction abort, IO errors, whatever), then we can still
	 * do these next steps (the fs will already have been marked as
	 * having errors), but we can't free the inode if the mark_dirty
	 * fails.
	 */
223
	if (ext4_mark_inode_dirty(handle, inode))
224 225 226
		/* If that failed, just do the required in-core inode clear. */
		clear_inode(inode);
	else
227 228
		ext4_free_inode(handle, inode);
	ext4_journal_stop(handle);
229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253
	return;
no_delete:
	clear_inode(inode);	/* We must guarantee clearing of inode... */
}

typedef struct {
	__le32	*p;
	__le32	key;
	struct buffer_head *bh;
} Indirect;

static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
	p->key = *(p->p = v);
	p->bh = bh;
}

static int verify_chain(Indirect *from, Indirect *to)
{
	while (from <= to && from->key == *from->p)
		from++;
	return (from > to);
}

/**
254
 *	ext4_block_to_path - parse the block number into array of offsets
255 256 257
 *	@inode: inode in question (we are only interested in its superblock)
 *	@i_block: block number to be parsed
 *	@offsets: array to store the offsets in
D
Dave Kleikamp 已提交
258 259
 *	@boundary: set this non-zero if the referred-to block is likely to be
 *	       followed (on disk) by an indirect block.
260
 *
261
 *	To store the locations of file's data ext4 uses a data structure common
262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
 *	for UNIX filesystems - tree of pointers anchored in the inode, with
 *	data blocks at leaves and indirect blocks in intermediate nodes.
 *	This function translates the block number into path in that tree -
 *	return value is the path length and @offsets[n] is the offset of
 *	pointer to (n+1)th node in the nth one. If @block is out of range
 *	(negative or too large) warning is printed and zero returned.
 *
 *	Note: function doesn't find node addresses, so no IO is needed. All
 *	we need to know is the capacity of indirect blocks (taken from the
 *	inode->i_sb).
 */

/*
 * Portability note: the last comparison (check that we fit into triple
 * indirect block) is spelled differently, because otherwise on an
 * architecture with 32-bit longs and 8Kb pages we might get into trouble
 * if our filesystem had 8Kb blocks. We might use long long, but that would
 * kill us on x86. Oh, well, at least the sign propagation does not matter -
 * i_block would have to be negative in the very beginning, so we would not
 * get there at all.
 */

284
static int ext4_block_to_path(struct inode *inode,
285 286
			long i_block, int offsets[4], int *boundary)
{
287 288 289
	int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
	int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
	const long direct_blocks = EXT4_NDIR_BLOCKS,
290 291 292 293 294 295
		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;
	int final = 0;

	if (i_block < 0) {
296
		ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0");
297 298 299 300
	} else if (i_block < direct_blocks) {
		offsets[n++] = i_block;
		final = direct_blocks;
	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
301
		offsets[n++] = EXT4_IND_BLOCK;
302 303 304
		offsets[n++] = i_block;
		final = ptrs;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
305
		offsets[n++] = EXT4_DIND_BLOCK;
306 307 308 309
		offsets[n++] = i_block >> ptrs_bits;
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
310
		offsets[n++] = EXT4_TIND_BLOCK;
311 312 313 314 315
		offsets[n++] = i_block >> (ptrs_bits * 2);
		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else {
316
		ext4_warning(inode->i_sb, "ext4_block_to_path", "block > big");
317 318 319 320 321 322 323
	}
	if (boundary)
		*boundary = final - 1 - (i_block & (ptrs - 1));
	return n;
}

/**
324
 *	ext4_get_branch - read the chain of indirect blocks leading to data
325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351
 *	@inode: inode in question
 *	@depth: depth of the chain (1 - direct pointer, etc.)
 *	@offsets: offsets of pointers in inode/indirect blocks
 *	@chain: place to store the result
 *	@err: here we store the error value
 *
 *	Function fills the array of triples <key, p, bh> and returns %NULL
 *	if everything went OK or the pointer to the last filled triple
 *	(incomplete one) otherwise. Upon the return chain[i].key contains
 *	the number of (i+1)-th block in the chain (as it is stored in memory,
 *	i.e. little-endian 32-bit), chain[i].p contains the address of that
 *	number (it points into struct inode for i==0 and into the bh->b_data
 *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
 *	block for i>0 and NULL for i==0. In other words, it holds the block
 *	numbers of the chain, addresses they were taken from (and where we can
 *	verify that chain did not change) and buffer_heads hosting these
 *	numbers.
 *
 *	Function stops when it stumbles upon zero pointer (absent block)
 *		(pointer to last triple returned, *@err == 0)
 *	or when it gets an IO error reading an indirect block
 *		(ditto, *@err == -EIO)
 *	or when it notices that chain had been changed while it was reading
 *		(ditto, *@err == -EAGAIN)
 *	or when it reads all @depth-1 indirect blocks successfully and finds
 *	the whole chain, all way to the data (returns %NULL, *err == 0).
 */
352
static Indirect *ext4_get_branch(struct inode *inode, int depth, int *offsets,
353 354 355 356 357 358 359 360
				 Indirect chain[4], int *err)
{
	struct super_block *sb = inode->i_sb;
	Indirect *p = chain;
	struct buffer_head *bh;

	*err = 0;
	/* i_data is not going away, no lock needed */
361
	add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets);
362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388
	if (!p->key)
		goto no_block;
	while (--depth) {
		bh = sb_bread(sb, le32_to_cpu(p->key));
		if (!bh)
			goto failure;
		/* Reader: pointers */
		if (!verify_chain(chain, p))
			goto changed;
		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
		/* Reader: end */
		if (!p->key)
			goto no_block;
	}
	return NULL;

changed:
	brelse(bh);
	*err = -EAGAIN;
	goto no_block;
failure:
	*err = -EIO;
no_block:
	return p;
}

/**
389
 *	ext4_find_near - find a place for allocation with sufficient locality
390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407
 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
 *	This function returns the prefered place for block allocation.
 *	It is used when heuristic for sequential allocation fails.
 *	Rules are:
 *	  + if there is a block to the left of our position - allocate near it.
 *	  + if pointer will live in indirect block - allocate near that block.
 *	  + if pointer will live in inode - allocate in the same
 *	    cylinder group.
 *
 * In the latter case we colour the starting block by the callers PID to
 * prevent it from clashing with concurrent allocations for a different inode
 * in the same block group.   The PID is used here so that functionally related
 * files will be close-by on-disk.
 *
 *	Caller must make sure that @ind is valid and will stay that way.
 */
408
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
409
{
410
	struct ext4_inode_info *ei = EXT4_I(inode);
411 412
	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
	__le32 *p;
413 414
	ext4_fsblk_t bg_start;
	ext4_grpblk_t colour;
415 416 417 418 419 420 421 422 423 424 425 426 427 428 429

	/* Try to find previous block */
	for (p = ind->p - 1; p >= start; p--) {
		if (*p)
			return le32_to_cpu(*p);
	}

	/* No such thing, so let's try location of indirect block */
	if (ind->bh)
		return ind->bh->b_blocknr;

	/*
	 * It is going to be referred to from the inode itself? OK, just put it
	 * into the same cylinder group then.
	 */
430
	bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
431
	colour = (current->pid % 16) *
432
			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
433 434 435 436
	return bg_start + colour;
}

/**
437
 *	ext4_find_goal - find a prefered place for allocation.
438 439 440 441 442 443 444 445 446 447
 *	@inode: owner
 *	@block:  block we want
 *	@chain:  chain of indirect blocks
 *	@partial: pointer to the last triple within a chain
 *	@goal:	place to store the result.
 *
 *	Normally this function find the prefered place for block allocation,
 *	stores it in *@goal and returns zero.
 */

448
static ext4_fsblk_t ext4_find_goal(struct inode *inode, long block,
449 450
		Indirect chain[4], Indirect *partial)
{
451
	struct ext4_block_alloc_info *block_i;
452

453
	block_i =  EXT4_I(inode)->i_block_alloc_info;
454 455 456 457 458 459 460 461 462 463

	/*
	 * try the heuristic for sequential allocation,
	 * failing that at least try to get decent locality.
	 */
	if (block_i && (block == block_i->last_alloc_logical_block + 1)
		&& (block_i->last_alloc_physical_block != 0)) {
		return block_i->last_alloc_physical_block + 1;
	}

464
	return ext4_find_near(inode, partial);
465 466 467
}

/**
468
 *	ext4_blks_to_allocate: Look up the block map and count the number
469 470 471 472 473 474 475 476 477 478
 *	of direct blocks need to be allocated for the given branch.
 *
 *	@branch: chain of indirect blocks
 *	@k: number of blocks need for indirect blocks
 *	@blks: number of data blocks to be mapped.
 *	@blocks_to_boundary:  the offset in the indirect block
 *
 *	return the total number of blocks to be allocate, including the
 *	direct and indirect blocks.
 */
479
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505
		int blocks_to_boundary)
{
	unsigned long count = 0;

	/*
	 * Simple case, [t,d]Indirect block(s) has not allocated yet
	 * then it's clear blocks on that path have not allocated
	 */
	if (k > 0) {
		/* right now we don't handle cross boundary allocation */
		if (blks < blocks_to_boundary + 1)
			count += blks;
		else
			count += blocks_to_boundary + 1;
		return count;
	}

	count++;
	while (count < blks && count <= blocks_to_boundary &&
		le32_to_cpu(*(branch[0].p + count)) == 0) {
		count++;
	}
	return count;
}

/**
506
 *	ext4_alloc_blocks: multiple allocate blocks needed for a branch
507 508 509 510 511 512 513 514
 *	@indirect_blks: the number of blocks need to allocate for indirect
 *			blocks
 *
 *	@new_blocks: on return it will store the new block numbers for
 *	the indirect blocks(if needed) and the first direct block,
 *	@blks:	on return it will store the total number of allocated
 *		direct blocks
 */
515 516 517
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
			ext4_fsblk_t goal, int indirect_blks, int blks,
			ext4_fsblk_t new_blocks[4], int *err)
518 519 520 521
{
	int target, i;
	unsigned long count = 0;
	int index = 0;
522
	ext4_fsblk_t current_block = 0;
523 524 525 526 527 528 529 530 531 532 533 534 535 536 537
	int ret = 0;

	/*
	 * Here we try to allocate the requested multiple blocks at once,
	 * on a best-effort basis.
	 * To build a branch, we should allocate blocks for
	 * the indirect blocks(if not allocated yet), and at least
	 * the first direct block of this branch.  That's the
	 * minimum number of blocks need to allocate(required)
	 */
	target = blks + indirect_blks;

	while (1) {
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
538
		current_block = ext4_new_blocks(handle,inode,goal,&count,err);
539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561
		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}

		if (count > 0)
			break;
	}

	/* save the new block number for the first direct block */
	new_blocks[index] = current_block;

	/* total number of blocks allocated for direct blocks */
	ret = count;
	*err = 0;
	return ret;
failed_out:
	for (i = 0; i <index; i++)
562
		ext4_free_blocks(handle, inode, new_blocks[i], 1);
563 564 565 566
	return ret;
}

/**
567
 *	ext4_alloc_branch - allocate and set up a chain of blocks.
568 569 570 571 572 573 574 575 576 577
 *	@inode: owner
 *	@indirect_blks: number of allocated indirect blocks
 *	@blks: number of allocated direct blocks
 *	@offsets: offsets (in the blocks) to store the pointers to next.
 *	@branch: place to store the chain in.
 *
 *	This function allocates blocks, zeroes out all but the last one,
 *	links them into chain and (if we are synchronous) writes them to disk.
 *	In other words, it prepares a branch that can be spliced onto the
 *	inode. It stores the information about that chain in the branch[], in
578
 *	the same format as ext4_get_branch() would do. We are calling it after
579 580
 *	we had read the existing part of chain and partial points to the last
 *	triple of that (one with zero ->key). Upon the exit we have the same
581
 *	picture as after the successful ext4_get_block(), except that in one
582 583 584 585 586 587
 *	place chain is disconnected - *branch->p is still zero (we did not
 *	set the last link), but branch->key contains the number that should
 *	be placed into *branch->p to fill that gap.
 *
 *	If allocation fails we free all blocks we've allocated (and forget
 *	their buffer_heads) and return the error value the from failed
588
 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
589 590
 *	as described above and return 0.
 */
591 592
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
			int indirect_blks, int *blks, ext4_fsblk_t goal,
593 594 595 596 597 598 599
			int *offsets, Indirect *branch)
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
600 601
	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
602

603
	num = ext4_alloc_blocks(handle, inode, goal, indirect_blks,
604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621
				*blks, new_blocks, &err);
	if (err)
		return err;

	branch[0].key = cpu_to_le32(new_blocks[0]);
	/*
	 * metadata blocks and data blocks are allocated.
	 */
	for (n = 1; n <= indirect_blks;  n++) {
		/*
		 * Get buffer_head for parent block, zero it out
		 * and set the pointer to new one, then send
		 * parent to disk.
		 */
		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
		branch[n].bh = bh;
		lock_buffer(bh);
		BUFFER_TRACE(bh, "call get_create_access");
622
		err = ext4_journal_get_create_access(handle, bh);
623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646
		if (err) {
			unlock_buffer(bh);
			brelse(bh);
			goto failed;
		}

		memset(bh->b_data, 0, blocksize);
		branch[n].p = (__le32 *) bh->b_data + offsets[n];
		branch[n].key = cpu_to_le32(new_blocks[n]);
		*branch[n].p = branch[n].key;
		if ( n == indirect_blks) {
			current_block = new_blocks[n];
			/*
			 * End of chain, update the last new metablock of
			 * the chain to point to the new allocated
			 * data blocks numbers
			 */
			for (i=1; i < num; i++)
				*(branch[n].p + i) = cpu_to_le32(++current_block);
		}
		BUFFER_TRACE(bh, "marking uptodate");
		set_buffer_uptodate(bh);
		unlock_buffer(bh);

647 648
		BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, bh);
649 650 651 652 653 654 655 656
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
657
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
658
		ext4_journal_forget(handle, branch[i].bh);
659 660
	}
	for (i = 0; i <indirect_blks; i++)
661
		ext4_free_blocks(handle, inode, new_blocks[i], 1);
662

663
	ext4_free_blocks(handle, inode, new_blocks[i], num);
664 665 666 667 668

	return err;
}

/**
669
 * ext4_splice_branch - splice the allocated branch onto inode.
670 671 672
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
673
 *	ext4_alloc_branch)
674 675 676 677 678 679 680 681
 * @where: location of missing link
 * @num:   number of indirect blocks we are adding
 * @blks:  number of direct blocks we are adding
 *
 * This function fills the missing link and does all housekeeping needed in
 * inode (->i_blocks, etc.). In case of success we end up with the full
 * chain to new block and return 0.
 */
682
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
683 684 685 686
			long block, Indirect *where, int num, int blks)
{
	int i;
	int err = 0;
687 688
	struct ext4_block_alloc_info *block_i;
	ext4_fsblk_t current_block;
689

690
	block_i = EXT4_I(inode)->i_block_alloc_info;
691 692 693 694 695 696 697
	/*
	 * If we're splicing into a [td]indirect block (as opposed to the
	 * inode) then we need to get write access to the [td]indirect block
	 * before the splice.
	 */
	if (where->bh) {
		BUFFER_TRACE(where->bh, "get_write_access");
698
		err = ext4_journal_get_write_access(handle, where->bh);
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728
		if (err)
			goto err_out;
	}
	/* That's it */

	*where->p = where->key;

	/*
	 * Update the host buffer_head or inode to point to more just allocated
	 * direct blocks blocks
	 */
	if (num == 0 && blks > 1) {
		current_block = le32_to_cpu(where->key) + 1;
		for (i = 1; i < blks; i++)
			*(where->p + i ) = cpu_to_le32(current_block++);
	}

	/*
	 * update the most recently allocated logical & physical block
	 * in i_block_alloc_info, to assist find the proper goal block for next
	 * allocation
	 */
	if (block_i) {
		block_i->last_alloc_logical_block = block + blks - 1;
		block_i->last_alloc_physical_block =
				le32_to_cpu(where[num].key) + blks - 1;
	}

	/* We are done with atomic stuff, now do the rest of housekeeping */

K
Kalpak Shah 已提交
729
	inode->i_ctime = ext4_current_time(inode);
730
	ext4_mark_inode_dirty(handle, inode);
731 732 733 734 735 736 737 738 739

	/* had we spliced it onto indirect block? */
	if (where->bh) {
		/*
		 * If we spliced it onto an indirect block, we haven't
		 * altered the inode.  Note however that if it is being spliced
		 * onto an indirect block at the very end of the file (the
		 * file is growing) then we *will* alter the inode to reflect
		 * the new i_size.  But that is not done here - it is done in
740
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
741 742
		 */
		jbd_debug(5, "splicing indirect only\n");
743 744
		BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, where->bh);
745 746 747 748 749 750 751 752 753 754 755 756 757
		if (err)
			goto err_out;
	} else {
		/*
		 * OK, we spliced it into the inode itself on a direct block.
		 * Inode was dirtied above.
		 */
		jbd_debug(5, "splicing direct\n");
	}
	return err;

err_out:
	for (i = 1; i <= num; i++) {
758
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
759 760
		ext4_journal_forget(handle, where[i].bh);
		ext4_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
761
	}
762
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785

	return err;
}

/*
 * Allocation strategy is simple: if we have to allocate something, we will
 * have to go the whole way to leaf. So let's do it before attaching anything
 * to tree, set linkage between the newborn blocks, write them if sync is
 * required, recheck the path, free and repeat if check fails, otherwise
 * set the last missing link (that will protect us from any truncate-generated
 * removals - all blocks on the path are immune now) and possibly force the
 * write on the parent block.
 * That has a nice additional property: no special recovery from the failed
 * allocations is needed - we simply release blocks and do not touch anything
 * reachable from inode.
 *
 * `handle' can be NULL if create == 0.
 *
 * The BKL may not be held on entry here.  Be sure to take it early.
 * return > 0, # of blocks mapped or allocated.
 * return = 0, if plain lookup failed.
 * return < 0, error case.
 */
786
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
787 788 789 790 791 792 793 794
		sector_t iblock, unsigned long maxblocks,
		struct buffer_head *bh_result,
		int create, int extend_disksize)
{
	int err = -EIO;
	int offsets[4];
	Indirect chain[4];
	Indirect *partial;
795
	ext4_fsblk_t goal;
796 797 798
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
799
	struct ext4_inode_info *ei = EXT4_I(inode);
800
	int count = 0;
801
	ext4_fsblk_t first_block = 0;
802 803


A
Alex Tomas 已提交
804
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
805
	J_ASSERT(handle != NULL || create == 0);
806
	depth = ext4_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
807 808 809 810

	if (depth == 0)
		goto out;

811
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
812 813 814 815 816 817 818 819

	/* Simplest case - block found, no allocation needed */
	if (!partial) {
		first_block = le32_to_cpu(chain[depth - 1].key);
		clear_buffer_new(bh_result);
		count++;
		/*map more blocks*/
		while (count < maxblocks && count <= blocks_to_boundary) {
820
			ext4_fsblk_t blk;
821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852

			if (!verify_chain(chain, partial)) {
				/*
				 * Indirect block might be removed by
				 * truncate while we were reading it.
				 * Handling of that case: forget what we've
				 * got now. Flag the err as EAGAIN, so it
				 * will reread.
				 */
				err = -EAGAIN;
				count = 0;
				break;
			}
			blk = le32_to_cpu(*(chain[depth-1].p + count));

			if (blk == first_block + count)
				count++;
			else
				break;
		}
		if (err != -EAGAIN)
			goto got_it;
	}

	/* Next simple case - plain lookup or failed read of indirect block */
	if (!create || err == -EIO)
		goto cleanup;

	mutex_lock(&ei->truncate_mutex);

	/*
	 * If the indirect block is missing while we are reading
853
	 * the chain(ext4_get_branch() returns -EAGAIN err), or
854 855 856 857 858 859 860 861 862 863 864 865 866 867
	 * if the chain has been changed after we grab the semaphore,
	 * (either because another process truncated this branch, or
	 * another get_block allocated this branch) re-grab the chain to see if
	 * the request block has been allocated or not.
	 *
	 * Since we already block the truncate/other get_block
	 * at this point, we will have the current copy of the chain when we
	 * splice the branch into the tree.
	 */
	if (err == -EAGAIN || !verify_chain(chain, partial)) {
		while (partial > chain) {
			brelse(partial->bh);
			partial--;
		}
868
		partial = ext4_get_branch(inode, depth, offsets, chain, &err);
869 870 871 872 873 874 875 876 877 878 879 880 881 882 883
		if (!partial) {
			count++;
			mutex_unlock(&ei->truncate_mutex);
			if (err)
				goto cleanup;
			clear_buffer_new(bh_result);
			goto got_it;
		}
	}

	/*
	 * Okay, we need to do block allocation.  Lazily initialize the block
	 * allocation info here if necessary
	*/
	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
884
		ext4_init_block_alloc_info(inode);
885

886
	goal = ext4_find_goal(inode, iblock, chain, partial);
887 888 889 890 891 892 893 894

	/* the number of blocks need to allocate for [d,t]indirect blocks */
	indirect_blks = (chain + depth) - partial - 1;

	/*
	 * Next look up the indirect map to count the totoal number of
	 * direct blocks to allocate for this branch.
	 */
895
	count = ext4_blks_to_allocate(partial, indirect_blks,
896 897
					maxblocks, blocks_to_boundary);
	/*
898
	 * Block out ext4_truncate while we alter the tree
899
	 */
900
	err = ext4_alloc_branch(handle, inode, indirect_blks, &count, goal,
901 902 903
				offsets + (partial - chain), partial);

	/*
904
	 * The ext4_splice_branch call will free and forget any buffers
905 906 907 908 909 910
	 * on the new chain if there is a failure, but that risks using
	 * up transaction credits, especially for bitmaps where the
	 * credits cannot be returned.  Can we handle this somehow?  We
	 * may need to return -EAGAIN upwards in the worst case.  --sct
	 */
	if (!err)
911
		err = ext4_splice_branch(handle, inode, iblock,
912 913 914 915
					partial, indirect_blks, count);
	/*
	 * i_disksize growing is protected by truncate_mutex.  Don't forget to
	 * protect it if you're about to implement concurrent
916
	 * ext4_get_block() -bzzz
917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942
	*/
	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
		ei->i_disksize = inode->i_size;
	mutex_unlock(&ei->truncate_mutex);
	if (err)
		goto cleanup;

	set_buffer_new(bh_result);
got_it:
	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
	if (count > blocks_to_boundary)
		set_buffer_boundary(bh_result);
	err = count;
	/* Clean up and exit */
	partial = chain + depth - 1;	/* the whole chain */
cleanup:
	while (partial > chain) {
		BUFFER_TRACE(partial->bh, "call brelse");
		brelse(partial->bh);
		partial--;
	}
	BUFFER_TRACE(bh_result, "returned");
out:
	return err;
}

943
#define DIO_CREDITS (EXT4_RESERVE_TRANS_BLOCKS + 32)
944

945
static int ext4_get_block(struct inode *inode, sector_t iblock,
946 947
			struct buffer_head *bh_result, int create)
{
948
	handle_t *handle = ext4_journal_current_handle();
949 950 951 952 953 954 955 956 957 958 959 960 961 962
	int ret = 0;
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

	if (!create)
		goto get_block;		/* A read */

	if (max_blocks == 1)
		goto get_block;		/* A single block get */

	if (handle->h_transaction->t_state == T_LOCKED) {
		/*
		 * Huge direct-io writes can hold off commits for long
		 * periods of time.  Let this commit run.
		 */
963 964
		ext4_journal_stop(handle);
		handle = ext4_journal_start(inode, DIO_CREDITS);
965 966 967 968 969
		if (IS_ERR(handle))
			ret = PTR_ERR(handle);
		goto get_block;
	}

970
	if (handle->h_buffer_credits <= EXT4_RESERVE_TRANS_BLOCKS) {
971 972 973
		/*
		 * Getting low on buffer credits...
		 */
974
		ret = ext4_journal_extend(handle, DIO_CREDITS);
975 976 977 978
		if (ret > 0) {
			/*
			 * Couldn't extend the transaction.  Start a new one.
			 */
979
			ret = ext4_journal_restart(handle, DIO_CREDITS);
980 981 982 983 984
		}
	}

get_block:
	if (ret == 0) {
A
Alex Tomas 已提交
985
		ret = ext4_get_blocks_wrap(handle, inode, iblock,
986 987 988 989 990 991 992 993 994 995 996 997
					max_blocks, bh_result, create, 0);
		if (ret > 0) {
			bh_result->b_size = (ret << inode->i_blkbits);
			ret = 0;
		}
	}
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
998
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
999 1000 1001 1002 1003 1004 1005 1006 1007 1008
				long block, int create, int *errp)
{
	struct buffer_head dummy;
	int fatal = 0, err;

	J_ASSERT(handle != NULL || create == 0);

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	buffer_trace_init(&dummy.b_history);
A
Alex Tomas 已提交
1009
	err = ext4_get_blocks_wrap(handle, inode, block, 1,
1010 1011
					&dummy, create, 1);
	/*
1012
	 * ext4_get_blocks_handle() returns number of blocks
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035
	 * mapped. 0 in case of a HOLE.
	 */
	if (err > 0) {
		if (err > 1)
			WARN_ON(1);
		err = 0;
	}
	*errp = err;
	if (!err && buffer_mapped(&dummy)) {
		struct buffer_head *bh;
		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
		if (!bh) {
			*errp = -EIO;
			goto err;
		}
		if (buffer_new(&dummy)) {
			J_ASSERT(create != 0);
			J_ASSERT(handle != 0);

			/*
			 * Now that we do not always journal data, we should
			 * keep in mind whether this should always journal the
			 * new buffer as metadata.  For now, regular file
1036
			 * writes use ext4_get_block instead, so it's not a
1037 1038 1039 1040
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1041
			fatal = ext4_journal_get_create_access(handle, bh);
1042 1043 1044 1045 1046
			if (!fatal && !buffer_uptodate(bh)) {
				memset(bh->b_data,0,inode->i_sb->s_blocksize);
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1047 1048
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			err = ext4_journal_dirty_metadata(handle, bh);
1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
			if (!fatal)
				fatal = err;
		} else {
			BUFFER_TRACE(bh, "not a new buffer");
		}
		if (fatal) {
			*errp = fatal;
			brelse(bh);
			bh = NULL;
		}
		return bh;
	}
err:
	return NULL;
}

1065
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1066 1067 1068 1069
			       int block, int create, int *err)
{
	struct buffer_head * bh;

1070
	bh = ext4_getblk(handle, inode, block, create, err);
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
	if (!bh)
		return bh;
	if (buffer_uptodate(bh))
		return bh;
	ll_rw_block(READ_META, 1, &bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;
	put_bh(bh);
	*err = -EIO;
	return NULL;
}

static int walk_page_buffers(	handle_t *handle,
				struct buffer_head *head,
				unsigned from,
				unsigned to,
				int *partial,
				int (*fn)(	handle_t *handle,
						struct buffer_head *bh))
{
	struct buffer_head *bh;
	unsigned block_start, block_end;
	unsigned blocksize = head->b_size;
	int err, ret = 0;
	struct buffer_head *next;

	for (	bh = head, block_start = 0;
		ret == 0 && (bh != head || !block_start);
		block_start = block_end, bh = next)
	{
		next = bh->b_this_page;
		block_end = block_start + blocksize;
		if (block_end <= from || block_start >= to) {
			if (partial && !buffer_uptodate(bh))
				*partial = 1;
			continue;
		}
		err = (*fn)(handle, bh);
		if (!ret)
			ret = err;
	}
	return ret;
}

/*
 * To preserve ordering, it is essential that the hole instantiation and
 * the data write be encapsulated in a single transaction.  We cannot
1119
 * close off a transaction and start a new one between the ext4_get_block()
1120
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1121 1122
 * prepare_write() is the right place.
 *
1123 1124
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1125 1126 1127 1128
 * has generated enough buffer credits to do the whole page.  So we won't
 * block on the journal in that case, which is good, because the caller may
 * be PF_MEMALLOC.
 *
1129
 * By accident, ext4 can be reentered when a transaction is open via
1130 1131 1132 1133 1134 1135
 * quota file writes.  If we were to commit the transaction while thus
 * reentered, there can be a deadlock - we would be holding a quota
 * lock, and the commit would never complete if another thread had a
 * transaction open and was blocking on the quota lock - a ranking
 * violation.
 *
1136
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1137 1138 1139 1140 1141 1142 1143 1144 1145
 * will _not_ run commit under these circumstances because handle->h_ref
 * is elevated.  We'll still have enough credits for the tiny quotafile
 * write.
 */
static int do_journal_get_write_access(handle_t *handle,
					struct buffer_head *bh)
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
1146
	return ext4_journal_get_write_access(handle, bh);
1147 1148
}

1149
static int ext4_prepare_write(struct file *file, struct page *page,
1150 1151 1152
			      unsigned from, unsigned to)
{
	struct inode *inode = page->mapping->host;
1153
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1154 1155 1156 1157
	handle_t *handle;
	int retries = 0;

retry:
1158
	handle = ext4_journal_start(inode, needed_blocks);
1159 1160 1161 1162
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out;
	}
1163 1164
	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
		ret = nobh_prepare_write(page, from, to, ext4_get_block);
1165
	else
1166
		ret = block_prepare_write(page, from, to, ext4_get_block);
1167
	if (ret)
1168
		goto prepare_write_failed;
1169

1170
	if (ext4_should_journal_data(inode)) {
1171 1172 1173
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
1174 1175 1176
prepare_write_failed:
	if (ret)
		ext4_journal_stop(handle);
1177
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1178
		goto retry;
1179
out:
1180 1181 1182
	return ret;
}

1183
int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1184
{
1185
	int err = jbd2_journal_dirty_data(handle, bh);
1186
	if (err)
1187
		ext4_journal_abort_handle(__FUNCTION__, __FUNCTION__,
1188 1189 1190 1191 1192 1193 1194 1195 1196 1197
						bh, handle,err);
	return err;
}

/* For commit_write() in data=journal mode */
static int commit_write_fn(handle_t *handle, struct buffer_head *bh)
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1198
	return ext4_journal_dirty_metadata(handle, bh);
1199 1200 1201 1202 1203 1204
}

/*
 * We need to pick up the new inode size which generic_commit_write gave us
 * `file' can be NULL - eg, when called from page_symlink().
 *
1205
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1206 1207
 * buffers are managed internally.
 */
1208
static int ext4_ordered_commit_write(struct file *file, struct page *page,
1209 1210
			     unsigned from, unsigned to)
{
1211
	handle_t *handle = ext4_journal_current_handle();
1212 1213 1214 1215
	struct inode *inode = page->mapping->host;
	int ret = 0, ret2;

	ret = walk_page_buffers(handle, page_buffers(page),
1216
		from, to, NULL, ext4_journal_dirty_data);
1217 1218 1219 1220 1221 1222 1223 1224 1225 1226

	if (ret == 0) {
		/*
		 * generic_commit_write() will run mark_inode_dirty() if i_size
		 * changes.  So let's piggyback the i_disksize mark_inode_dirty
		 * into that.
		 */
		loff_t new_i_size;

		new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1227 1228
		if (new_i_size > EXT4_I(inode)->i_disksize)
			EXT4_I(inode)->i_disksize = new_i_size;
1229 1230
		ret = generic_commit_write(file, page, from, to);
	}
1231
	ret2 = ext4_journal_stop(handle);
1232 1233 1234 1235 1236
	if (!ret)
		ret = ret2;
	return ret;
}

1237
static int ext4_writeback_commit_write(struct file *file, struct page *page,
1238 1239
			     unsigned from, unsigned to)
{
1240
	handle_t *handle = ext4_journal_current_handle();
1241 1242 1243 1244 1245
	struct inode *inode = page->mapping->host;
	int ret = 0, ret2;
	loff_t new_i_size;

	new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1246 1247
	if (new_i_size > EXT4_I(inode)->i_disksize)
		EXT4_I(inode)->i_disksize = new_i_size;
1248

1249
	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
1250 1251 1252 1253
		ret = nobh_commit_write(file, page, from, to);
	else
		ret = generic_commit_write(file, page, from, to);

1254
	ret2 = ext4_journal_stop(handle);
1255 1256 1257 1258 1259
	if (!ret)
		ret = ret2;
	return ret;
}

1260
static int ext4_journalled_commit_write(struct file *file,
1261 1262
			struct page *page, unsigned from, unsigned to)
{
1263
	handle_t *handle = ext4_journal_current_handle();
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
	struct inode *inode = page->mapping->host;
	int ret = 0, ret2;
	int partial = 0;
	loff_t pos;

	/*
	 * Here we duplicate the generic_commit_write() functionality
	 */
	pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;

	ret = walk_page_buffers(handle, page_buffers(page), from,
				to, &partial, commit_write_fn);
	if (!partial)
		SetPageUptodate(page);
	if (pos > inode->i_size)
		i_size_write(inode, pos);
1280 1281 1282 1283
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
	if (inode->i_size > EXT4_I(inode)->i_disksize) {
		EXT4_I(inode)->i_disksize = inode->i_size;
		ret2 = ext4_mark_inode_dirty(handle, inode);
1284 1285 1286
		if (!ret)
			ret = ret2;
	}
1287
	ret2 = ext4_journal_stop(handle);
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297
	if (!ret)
		ret = ret2;
	return ret;
}

/*
 * bmap() is special.  It gets used by applications such as lilo and by
 * the swapper to find the on-disk block of a specific piece of data.
 *
 * Naturally, this is dangerous if the block concerned is still in the
1298
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
1299 1300 1301 1302 1303 1304 1305 1306
 * filesystem and enables swap, then they may get a nasty shock when the
 * data getting swapped to that swapfile suddenly gets overwritten by
 * the original zero's written out previously to the journal and
 * awaiting writeback in the kernel's buffer cache.
 *
 * So, if we see any bmap calls here on a modified, data-journaled file,
 * take extra steps to flush any blocks which might be in the cache.
 */
1307
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
1308 1309 1310 1311 1312
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

1313
	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
		/*
		 * This is a REALLY heavyweight approach, but the use of
		 * bmap on dirty files is expected to be extremely rare:
		 * only if we run lilo or swapon on a freshly made file
		 * do we expect this to happen.
		 *
		 * (bmap requires CAP_SYS_RAWIO so this does not
		 * represent an unprivileged user DOS attack --- we'd be
		 * in trouble if mortal users could trigger this path at
		 * will.)
		 *
1325
		 * NB. EXT4_STATE_JDATA is not set on files other than
1326 1327 1328 1329 1330 1331
		 * regular files.  If somebody wants to bmap a directory
		 * or symlink and gets confused because the buffer
		 * hasn't yet been flushed to disk, they deserve
		 * everything they get.
		 */

1332 1333
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
1334 1335 1336
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
1337 1338 1339 1340 1341

		if (err)
			return 0;
	}

1342
	return generic_block_bmap(mapping,block,ext4_get_block);
1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356
}

static int bget_one(handle_t *handle, struct buffer_head *bh)
{
	get_bh(bh);
	return 0;
}

static int bput_one(handle_t *handle, struct buffer_head *bh)
{
	put_bh(bh);
	return 0;
}

1357
static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1358 1359
{
	if (buffer_mapped(bh))
1360
		return ext4_journal_dirty_data(handle, bh);
1361 1362 1363 1364 1365 1366
	return 0;
}

/*
 * Note that we always start a transaction even if we're not journalling
 * data.  This is to preserve ordering: any hole instantiation within
1367
 * __block_write_full_page -> ext4_get_block() should be journalled
1368 1369 1370 1371 1372 1373 1374
 * along with the data so we don't crash and then get metadata which
 * refers to old data.
 *
 * In all journalling modes block_write_full_page() will start the I/O.
 *
 * Problem:
 *
1375 1376
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
1377 1378 1379
 *
 * Similar for:
 *
1380
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1381
 *
1382
 * Same applies to ext4_get_block().  We will deadlock on various things like
1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415
 * lock_journal and i_truncate_mutex.
 *
 * Setting PF_MEMALLOC here doesn't work - too many internal memory
 * allocations fail.
 *
 * 16May01: If we're reentered then journal_current_handle() will be
 *	    non-zero. We simply *return*.
 *
 * 1 July 2001: @@@ FIXME:
 *   In journalled data mode, a data buffer may be metadata against the
 *   current transaction.  But the same file is part of a shared mapping
 *   and someone does a writepage() on it.
 *
 *   We will move the buffer onto the async_data list, but *after* it has
 *   been dirtied. So there's a small window where we have dirty data on
 *   BJ_Metadata.
 *
 *   Note that this only applies to the last partial page in the file.  The
 *   bit which block_write_full_page() uses prepare/commit for.  (That's
 *   broken code anyway: it's wrong for msync()).
 *
 *   It's a rare case: affects the final partial page, for journalled data
 *   where the file is subject to bith write() and writepage() in the same
 *   transction.  To fix it we'll need a custom block_write_full_page().
 *   We'll probably need that anyway for journalling writepage() output.
 *
 * We don't honour synchronous mounts for writepage().  That would be
 * disastrous.  Any write() or metadata operation will sync the fs for
 * us.
 *
 * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
 * we don't need to open a transaction here.
 */
1416
static int ext4_ordered_writepage(struct page *page,
1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct buffer_head *page_bufs;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	J_ASSERT(PageLocked(page));

	/*
	 * We give up here if we're reentered, because it might be for a
	 * different filesystem.
	 */
1431
	if (ext4_journal_current_handle())
1432 1433
		goto out_fail;

1434
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448

	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out_fail;
	}

	if (!page_has_buffers(page)) {
		create_empty_buffers(page, inode->i_sb->s_blocksize,
				(1 << BH_Dirty)|(1 << BH_Uptodate));
	}
	page_bufs = page_buffers(page);
	walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, bget_one);

1449
	ret = block_write_full_page(page, ext4_get_block, wbc);
1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464

	/*
	 * The page can become unlocked at any point now, and
	 * truncate can then come in and change things.  So we
	 * can't touch *page from now on.  But *page_bufs is
	 * safe due to elevated refcount.
	 */

	/*
	 * And attach them to the current transaction.  But only if
	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
	 * and generally junk.
	 */
	if (ret == 0) {
		err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1465
					NULL, jbd2_journal_dirty_data_fn);
1466 1467 1468 1469 1470
		if (!ret)
			ret = err;
	}
	walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, bput_one);
1471
	err = ext4_journal_stop(handle);
1472 1473 1474 1475 1476 1477 1478 1479 1480 1481
	if (!ret)
		ret = err;
	return ret;

out_fail:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return ret;
}

1482
static int ext4_writeback_writepage(struct page *page,
1483 1484 1485 1486 1487 1488 1489
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

1490
	if (ext4_journal_current_handle())
1491 1492
		goto out_fail;

1493
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1494 1495 1496 1497 1498
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out_fail;
	}

1499 1500
	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
		ret = nobh_writepage(page, ext4_get_block, wbc);
1501
	else
1502
		ret = block_write_full_page(page, ext4_get_block, wbc);
1503

1504
	err = ext4_journal_stop(handle);
1505 1506 1507 1508 1509 1510 1511 1512 1513 1514
	if (!ret)
		ret = err;
	return ret;

out_fail:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return ret;
}

1515
static int ext4_journalled_writepage(struct page *page,
1516 1517 1518 1519 1520 1521 1522
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

1523
	if (ext4_journal_current_handle())
1524 1525
		goto no_write;

1526
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto no_write;
	}

	if (!page_has_buffers(page) || PageChecked(page)) {
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
1539
					ext4_get_block);
1540
		if (ret != 0) {
1541
			ext4_journal_stop(handle);
1542 1543 1544 1545 1546 1547 1548 1549 1550
			goto out_unlock;
		}
		ret = walk_page_buffers(handle, page_buffers(page), 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);

		err = walk_page_buffers(handle, page_buffers(page), 0,
				PAGE_CACHE_SIZE, NULL, commit_write_fn);
		if (ret == 0)
			ret = err;
1551
		EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1552 1553 1554 1555 1556 1557 1558
		unlock_page(page);
	} else {
		/*
		 * It may be a page full of checkpoint-mode buffers.  We don't
		 * really know unless we go poke around in the buffer_heads.
		 * But block_write_full_page will do the right thing.
		 */
1559
		ret = block_write_full_page(page, ext4_get_block, wbc);
1560
	}
1561
	err = ext4_journal_stop(handle);
1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
	if (!ret)
		ret = err;
out:
	return ret;

no_write:
	redirty_page_for_writepage(wbc, page);
out_unlock:
	unlock_page(page);
	goto out;
}

1574
static int ext4_readpage(struct file *file, struct page *page)
1575
{
1576
	return mpage_readpage(page, ext4_get_block);
1577 1578 1579
}

static int
1580
ext4_readpages(struct file *file, struct address_space *mapping,
1581 1582
		struct list_head *pages, unsigned nr_pages)
{
1583
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
1584 1585
}

1586
static void ext4_invalidatepage(struct page *page, unsigned long offset)
1587
{
1588
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1589 1590 1591 1592 1593 1594 1595

	/*
	 * If it's a full truncate we just forget about the pending dirtying
	 */
	if (offset == 0)
		ClearPageChecked(page);

1596
	jbd2_journal_invalidatepage(journal, page, offset);
1597 1598
}

1599
static int ext4_releasepage(struct page *page, gfp_t wait)
1600
{
1601
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1602 1603 1604 1605

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
1606
	return jbd2_journal_try_to_free_buffers(journal, page, wait);
1607 1608 1609 1610 1611 1612 1613 1614 1615 1616
}

/*
 * If the O_DIRECT write will extend the file then add this inode to the
 * orphan list.  So recovery will truncate it back to the original size
 * if the machine crashes during the write.
 *
 * If the O_DIRECT write is intantiating holes inside i_size and the machine
 * crashes then stale disk data _may_ be exposed inside the file.
 */
1617
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
1618 1619 1620 1621 1622
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
1623
	struct ext4_inode_info *ei = EXT4_I(inode);
1624 1625 1626 1627 1628 1629 1630 1631
	handle_t *handle = NULL;
	ssize_t ret;
	int orphan = 0;
	size_t count = iov_length(iov, nr_segs);

	if (rw == WRITE) {
		loff_t final_size = offset + count;

1632
		handle = ext4_journal_start(inode, DIO_CREDITS);
1633 1634 1635 1636 1637
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			goto out;
		}
		if (final_size > inode->i_size) {
1638
			ret = ext4_orphan_add(handle, inode);
1639 1640 1641 1642 1643 1644 1645 1646 1647
			if (ret)
				goto out_stop;
			orphan = 1;
			ei->i_disksize = inode->i_size;
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
1648
				 ext4_get_block, NULL);
1649 1650

	/*
1651
	 * Reacquire the handle: ext4_get_block() can restart the transaction
1652
	 */
1653
	handle = ext4_journal_current_handle();
1654 1655 1656 1657 1658 1659

out_stop:
	if (handle) {
		int err;

		if (orphan && inode->i_nlink)
1660
			ext4_orphan_del(handle, inode);
1661 1662 1663 1664 1665 1666 1667 1668 1669
		if (orphan && ret > 0) {
			loff_t end = offset + ret;
			if (end > inode->i_size) {
				ei->i_disksize = end;
				i_size_write(inode, end);
				/*
				 * We're going to return a positive `ret'
				 * here due to non-zero-length I/O, so there's
				 * no way of reporting error returns from
1670
				 * ext4_mark_inode_dirty() to userspace.  So
1671 1672
				 * ignore it.
				 */
1673
				ext4_mark_inode_dirty(handle, inode);
1674 1675
			}
		}
1676
		err = ext4_journal_stop(handle);
1677 1678 1679 1680 1681 1682 1683 1684
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
1685
 * Pages can be marked dirty completely asynchronously from ext4's journalling
1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696
 * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
 * much here because ->set_page_dirty is called under VFS locks.  The page is
 * not necessarily locked.
 *
 * We cannot just dirty the page and leave attached buffers clean, because the
 * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
 * or jbddirty because all the journalling code will explode.
 *
 * So what we do is to mark the page "pending dirty" and next time writepage
 * is called, propagate that into the buffers appropriately.
 */
1697
static int ext4_journalled_set_page_dirty(struct page *page)
1698 1699 1700 1701 1702
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

1703 1704 1705 1706
static const struct address_space_operations ext4_ordered_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_ordered_writepage,
1707
	.sync_page	= block_sync_page,
1708 1709 1710 1711 1712 1713
	.prepare_write	= ext4_prepare_write,
	.commit_write	= ext4_ordered_commit_write,
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1714 1715 1716
	.migratepage	= buffer_migrate_page,
};

1717 1718 1719 1720
static const struct address_space_operations ext4_writeback_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_writeback_writepage,
1721
	.sync_page	= block_sync_page,
1722 1723 1724 1725 1726 1727
	.prepare_write	= ext4_prepare_write,
	.commit_write	= ext4_writeback_commit_write,
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1728 1729 1730
	.migratepage	= buffer_migrate_page,
};

1731 1732 1733 1734
static const struct address_space_operations ext4_journalled_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_journalled_writepage,
1735
	.sync_page	= block_sync_page,
1736 1737 1738 1739 1740 1741
	.prepare_write	= ext4_prepare_write,
	.commit_write	= ext4_journalled_commit_write,
	.set_page_dirty	= ext4_journalled_set_page_dirty,
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
1742 1743
};

1744
void ext4_set_aops(struct inode *inode)
1745
{
1746 1747 1748 1749
	if (ext4_should_order_data(inode))
		inode->i_mapping->a_ops = &ext4_ordered_aops;
	else if (ext4_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext4_writeback_aops;
1750
	else
1751
		inode->i_mapping->a_ops = &ext4_journalled_aops;
1752 1753 1754
}

/*
1755
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
1756 1757 1758 1759
 * up to the end of the block which corresponds to `from'.
 * This required during truncate. We need to physically zero the tail end
 * of that block so it doesn't yield old data if the file is later grown.
 */
A
Alex Tomas 已提交
1760
int ext4_block_truncate_page(handle_t *handle, struct page *page,
1761 1762
		struct address_space *mapping, loff_t from)
{
1763
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
	unsigned blocksize, iblock, length, pos;
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
	int err = 0;

	blocksize = inode->i_sb->s_blocksize;
	length = blocksize - (offset & (blocksize - 1));
	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);

	/*
	 * For "nobh" option,  we can only work if we don't need to
	 * read-in the page - otherwise we create buffers to do the IO.
	 */
	if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
1779
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
1780
		zero_user_page(page, offset, length, KM_USER0);
1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804
		set_page_dirty(page);
		goto unlock;
	}

	if (!page_has_buffers(page))
		create_empty_buffers(page, blocksize, 0);

	/* Find the buffer that contains "offset" */
	bh = page_buffers(page);
	pos = blocksize;
	while (offset >= pos) {
		bh = bh->b_this_page;
		iblock++;
		pos += blocksize;
	}

	err = 0;
	if (buffer_freed(bh)) {
		BUFFER_TRACE(bh, "freed: skip");
		goto unlock;
	}

	if (!buffer_mapped(bh)) {
		BUFFER_TRACE(bh, "unmapped");
1805
		ext4_get_block(inode, iblock, bh, 0);
1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825
		/* unmapped? It's a hole - nothing to do */
		if (!buffer_mapped(bh)) {
			BUFFER_TRACE(bh, "still unmapped");
			goto unlock;
		}
	}

	/* Ok, it's mapped. Make sure it's up-to-date */
	if (PageUptodate(page))
		set_buffer_uptodate(bh);

	if (!buffer_uptodate(bh)) {
		err = -EIO;
		ll_rw_block(READ, 1, &bh);
		wait_on_buffer(bh);
		/* Uhhuh. Read error. Complain and punt. */
		if (!buffer_uptodate(bh))
			goto unlock;
	}

1826
	if (ext4_should_journal_data(inode)) {
1827
		BUFFER_TRACE(bh, "get write access");
1828
		err = ext4_journal_get_write_access(handle, bh);
1829 1830 1831 1832
		if (err)
			goto unlock;
	}

1833
	zero_user_page(page, offset, length, KM_USER0);
1834 1835 1836 1837

	BUFFER_TRACE(bh, "zeroed end of block");

	err = 0;
1838 1839
	if (ext4_should_journal_data(inode)) {
		err = ext4_journal_dirty_metadata(handle, bh);
1840
	} else {
1841 1842
		if (ext4_should_order_data(inode))
			err = ext4_journal_dirty_data(handle, bh);
1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
		mark_buffer_dirty(bh);
	}

unlock:
	unlock_page(page);
	page_cache_release(page);
	return err;
}

/*
 * Probably it should be a library function... search for first non-zero word
 * or memcmp with zero_page, whatever is better for particular architecture.
 * Linus?
 */
static inline int all_zeroes(__le32 *p, __le32 *q)
{
	while (p < q)
		if (*p++)
			return 0;
	return 1;
}

/**
1866
 *	ext4_find_shared - find the indirect blocks for partial truncation.
1867 1868
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
1869
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
1870 1871 1872
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
1873
 *	This is a helper function used by ext4_truncate().
1874 1875 1876 1877 1878 1879 1880
 *
 *	When we do truncate() we may have to clean the ends of several
 *	indirect blocks but leave the blocks themselves alive. Block is
 *	partially truncated if some data below the new i_size is refered
 *	from it (and it is on the path to the first completely truncated
 *	data block, indeed).  We have to free the top of that path along
 *	with everything to the right of the path. Since no allocation
1881
 *	past the truncation point is possible until ext4_truncate()
1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899
 *	finishes, we may safely do the latter, but top of branch may
 *	require special attention - pageout below the truncation point
 *	might try to populate it.
 *
 *	We atomically detach the top of branch from the tree, store the
 *	block number of its root in *@top, pointers to buffer_heads of
 *	partially truncated blocks - in @chain[].bh and pointers to
 *	their last elements that should not be removed - in
 *	@chain[].p. Return value is the pointer to last filled element
 *	of @chain.
 *
 *	The work left to caller to do the actual freeing of subtrees:
 *		a) free the subtree starting from *@top
 *		b) free the subtrees whose roots are stored in
 *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
 *		c) free the subtrees growing from the inode past the @chain[0].
 *			(no partially truncated stuff there).  */

1900
static Indirect *ext4_find_shared(struct inode *inode, int depth,
1901 1902 1903 1904 1905 1906 1907 1908 1909
			int offsets[4], Indirect chain[4], __le32 *top)
{
	Indirect *partial, *p;
	int k, err;

	*top = 0;
	/* Make k index the deepest non-null offest + 1 */
	for (k = depth; k > 1 && !offsets[k-1]; k--)
		;
1910
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932
	/* Writer: pointers */
	if (!partial)
		partial = chain + k-1;
	/*
	 * If the branch acquired continuation since we've looked at it -
	 * fine, it should all survive and (new) top doesn't belong to us.
	 */
	if (!partial->key && *partial->p)
		/* Writer: end */
		goto no_top;
	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
		;
	/*
	 * OK, we've found the last block that must survive. The rest of our
	 * branch should be detached before unlocking. However, if that rest
	 * of branch is all ours and does not grow immediately from the inode
	 * it's easier to cheat and just decrement partial->p.
	 */
	if (p == chain + k - 1 && p > chain) {
		p->p--;
	} else {
		*top = *p->p;
1933
		/* Nope, don't do this in ext4.  Must leave the tree intact */
1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

	while(partial > p) {
		brelse(partial->bh);
		partial--;
	}
no_top:
	return partial;
}

/*
 * Zero a number of block pointers in either an inode or an indirect block.
 * If we restart the transaction we must again get write access to the
 * indirect block for further modification.
 *
 * We release `count' blocks on disk, but (last - first) may be greater
 * than `count' because there can be holes in there.
 */
1956 1957
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
1958 1959 1960 1961 1962
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
1963 1964
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			ext4_journal_dirty_metadata(handle, bh);
1965
		}
1966 1967
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
1968 1969
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
1970
			ext4_journal_get_write_access(handle, bh);
1971 1972 1973 1974 1975
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
1976
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
1977
	 * on them.  We've already detached each block from the file, so
1978
	 * bforget() in jbd2_journal_forget() should be safe.
1979
	 *
1980
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
1981 1982 1983 1984 1985 1986 1987 1988
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
			struct buffer_head *bh;

			*p = 0;
			bh = sb_find_get_block(inode->i_sb, nr);
1989
			ext4_forget(handle, 0, inode, bh, nr);
1990 1991 1992
		}
	}

1993
	ext4_free_blocks(handle, inode, block_to_free, count);
1994 1995 1996
}

/**
1997
 * ext4_free_data - free a list of data blocks
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
 * @handle:	handle for this transaction
 * @inode:	inode we are dealing with
 * @this_bh:	indirect buffer_head which contains *@first and *@last
 * @first:	array of block numbers
 * @last:	points immediately past the end of array
 *
 * We are freeing all blocks refered from that array (numbers are stored as
 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
 *
 * We accumulate contiguous runs of blocks to free.  Conveniently, if these
 * blocks are contiguous then releasing them at one time will only affect one
 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
 * actually use a lot of journal space.
 *
 * @this_bh will be %NULL if @first and @last point into the inode's direct
 * block pointers.
 */
2015
static void ext4_free_data(handle_t *handle, struct inode *inode,
2016 2017 2018
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
2019
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2020 2021 2022 2023
	unsigned long count = 0;	    /* Number of blocks in the run */
	__le32 *block_to_free_p = NULL;	    /* Pointer into inode/ind
					       corresponding to
					       block_to_free */
2024
	ext4_fsblk_t nr;		    /* Current block # */
2025 2026 2027 2028 2029 2030
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
2031
		err = ext4_journal_get_write_access(handle, this_bh);
2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048
		/* Important: if we can't update the indirect pointers
		 * to the blocks, we can't free them. */
		if (err)
			return;
	}

	for (p = first; p < last; p++) {
		nr = le32_to_cpu(*p);
		if (nr) {
			/* accumulate blocks to free if they're contiguous */
			if (count == 0) {
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			} else if (nr == block_to_free + count) {
				count++;
			} else {
2049
				ext4_clear_blocks(handle, inode, this_bh,
2050 2051 2052 2053 2054 2055 2056 2057 2058 2059
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
2060
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
2061 2062 2063
				  count, block_to_free_p, p);

	if (this_bh) {
2064 2065
		BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
		ext4_journal_dirty_metadata(handle, this_bh);
2066 2067 2068 2069
	}
}

/**
2070
 *	ext4_free_branches - free an array of branches
2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081
 *	@handle: JBD handle for this transaction
 *	@inode:	inode we are dealing with
 *	@parent_bh: the buffer_head which contains *@first and *@last
 *	@first:	array of block numbers
 *	@last:	pointer immediately past the end of array
 *	@depth:	depth of the branches to free
 *
 *	We are freeing all blocks refered from these branches (numbers are
 *	stored as little-endian 32-bit) and updating @inode->i_blocks
 *	appropriately.
 */
2082
static void ext4_free_branches(handle_t *handle, struct inode *inode,
2083 2084 2085
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
2086
	ext4_fsblk_t nr;
2087 2088 2089 2090 2091 2092 2093
	__le32 *p;

	if (is_handle_aborted(handle))
		return;

	if (depth--) {
		struct buffer_head *bh;
2094
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108
		p = last;
		while (--p >= first) {
			nr = le32_to_cpu(*p);
			if (!nr)
				continue;		/* A hole */

			/* Go read the buffer for the next level down */
			bh = sb_bread(inode->i_sb, nr);

			/*
			 * A read failure? Report error and clear slot
			 * (should be rare).
			 */
			if (!bh) {
2109
				ext4_error(inode->i_sb, "ext4_free_branches",
2110
					   "Read failure, inode=%lu, block=%llu",
2111 2112 2113 2114 2115 2116
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
2117
			ext4_free_branches(handle, inode, bh,
2118 2119 2120 2121 2122 2123 2124 2125
					   (__le32*)bh->b_data,
					   (__le32*)bh->b_data + addr_per_block,
					   depth);

			/*
			 * We've probably journalled the indirect block several
			 * times during the truncate.  But it's no longer
			 * needed and we now drop it from the transaction via
2126
			 * jbd2_journal_revoke().
2127 2128 2129
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
2130
			 * transaction then jbd2_journal_forget() will simply
2131
			 * brelse() it.  That means that if the underlying
2132
			 * block is reallocated in ext4_get_block(),
2133 2134 2135 2136 2137 2138 2139 2140
			 * unmap_underlying_metadata() will find this block
			 * and will try to get rid of it.  damn, damn.
			 *
			 * If this block has already been committed to the
			 * journal, a revoke record will be written.  And
			 * revoke records must be emitted *before* clearing
			 * this block's bit in the bitmaps.
			 */
2141
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161

			/*
			 * Everything below this this pointer has been
			 * released.  Now let this top-of-subtree go.
			 *
			 * We want the freeing of this indirect block to be
			 * atomic in the journal with the updating of the
			 * bitmap block which owns it.  So make some room in
			 * the journal.
			 *
			 * We zero the parent pointer *after* freeing its
			 * pointee in the bitmaps, so if extend_transaction()
			 * for some reason fails to put the bitmap changes and
			 * the release into the same transaction, recovery
			 * will merely complain about releasing a free block,
			 * rather than leaking blocks.
			 */
			if (is_handle_aborted(handle))
				return;
			if (try_to_extend_transaction(handle, inode)) {
2162 2163
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
2164 2165
			}

2166
			ext4_free_blocks(handle, inode, nr, 1);
2167 2168 2169 2170 2171 2172 2173

			if (parent_bh) {
				/*
				 * The block which we have just freed is
				 * pointed to by an indirect block: journal it
				 */
				BUFFER_TRACE(parent_bh, "get_write_access");
2174
				if (!ext4_journal_get_write_access(handle,
2175 2176 2177
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
2178 2179
					"call ext4_journal_dirty_metadata");
					ext4_journal_dirty_metadata(handle,
2180 2181 2182 2183 2184 2185 2186
								    parent_bh);
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
2187
		ext4_free_data(handle, inode, parent_bh, first, last);
2188 2189 2190 2191
	}
}

/*
2192
 * ext4_truncate()
2193
 *
2194 2195
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211
 * simultaneously on behalf of the same inode.
 *
 * As we work through the truncate and commmit bits of it to the journal there
 * is one core, guiding principle: the file's tree must always be consistent on
 * disk.  We must be able to restart the truncate after a crash.
 *
 * The file's tree may be transiently inconsistent in memory (although it
 * probably isn't), but whenever we close off and commit a journal transaction,
 * the contents of (the filesystem + the journal) must be consistent and
 * restartable.  It's pretty simple, really: bottom up, right to left (although
 * left-to-right works OK too).
 *
 * Note that at recovery time, journal replay occurs *before* the restart of
 * truncate against the orphan inode list.
 *
 * The committed inode has the new, desired i_size (which is the same as
2212
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
2213
 * that this inode's truncate did not complete and it will again call
2214 2215
 * ext4_truncate() to have another go.  So there will be instantiated blocks
 * to the right of the truncation point in a crashed ext4 filesystem.  But
2216
 * that's fine - as long as they are linked from the inode, the post-crash
2217
 * ext4_truncate() run will find them and release them.
2218
 */
2219
void ext4_truncate(struct inode *inode)
2220 2221
{
	handle_t *handle;
2222
	struct ext4_inode_info *ei = EXT4_I(inode);
2223
	__le32 *i_data = ei->i_data;
2224
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237
	struct address_space *mapping = inode->i_mapping;
	int offsets[4];
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
	long last_block;
	unsigned blocksize = inode->i_sb->s_blocksize;
	struct page *page;

	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
	    S_ISLNK(inode->i_mode)))
		return;
2238
	if (ext4_inode_is_fast_symlink(inode))
2239 2240 2241 2242 2243 2244
		return;
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return;

	/*
	 * We have to lock the EOF page here, because lock_page() nests
2245
	 * outside jbd2_journal_start().
2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256
	 */
	if ((inode->i_size & (blocksize - 1)) == 0) {
		/* Block boundary? Nothing to do */
		page = NULL;
	} else {
		page = grab_cache_page(mapping,
				inode->i_size >> PAGE_CACHE_SHIFT);
		if (!page)
			return;
	}

A
Alex Tomas 已提交
2257 2258 2259
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
		return ext4_ext_truncate(inode, page);

2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271
	handle = start_transaction(inode);
	if (IS_ERR(handle)) {
		if (page) {
			clear_highpage(page);
			flush_dcache_page(page);
			unlock_page(page);
			page_cache_release(page);
		}
		return;		/* AKPM: return what? */
	}

	last_block = (inode->i_size + blocksize-1)
2272
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
2273 2274

	if (page)
2275
		ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2276

2277
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289
	if (n == 0)
		goto out_stop;	/* error */

	/*
	 * OK.  This truncate is going to happen.  We add the inode to the
	 * orphan list, so that if this truncate spans multiple transactions,
	 * and we crash, we will resume the truncate when the filesystem
	 * recovers.  It also marks the inode dirty, to catch the new size.
	 *
	 * Implication: the file must always be in a sane, consistent
	 * truncatable state while each transaction commits.
	 */
2290
	if (ext4_orphan_add(handle, inode))
2291 2292 2293 2294 2295 2296 2297
		goto out_stop;

	/*
	 * The orphan list entry will now protect us from any crash which
	 * occurs before the truncate completes, so it is now safe to propagate
	 * the new, shorter inode size (held for now in i_size) into the
	 * on-disk inode. We do this via i_disksize, which is the value which
2298
	 * ext4 *really* writes onto the disk inode.
2299 2300 2301 2302
	 */
	ei->i_disksize = inode->i_size;

	/*
2303
	 * From here we block out all ext4_get_block() callers who want to
2304 2305 2306 2307 2308
	 * modify the block allocation tree.
	 */
	mutex_lock(&ei->truncate_mutex);

	if (n == 1) {		/* direct blocks */
2309 2310
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
2311 2312 2313
		goto do_indirects;
	}

2314
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
2315 2316 2317 2318
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
2319
			ext4_free_branches(handle, inode, NULL,
2320 2321 2322 2323 2324 2325 2326 2327 2328
					   &nr, &nr+1, (chain+n-1) - partial);
			*partial->p = 0;
			/*
			 * We mark the inode dirty prior to restart,
			 * and prior to stop.  No need for it here.
			 */
		} else {
			/* Shared branch grows from an indirect block */
			BUFFER_TRACE(partial->bh, "get_write_access");
2329
			ext4_free_branches(handle, inode, partial->bh,
2330 2331 2332 2333 2334 2335
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
2336
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
2337 2338 2339 2340 2341 2342 2343 2344 2345 2346
				   (__le32*)partial->bh->b_data+addr_per_block,
				   (chain+n-1) - partial);
		BUFFER_TRACE(partial->bh, "call brelse");
		brelse (partial->bh);
		partial--;
	}
do_indirects:
	/* Kill the remaining (whole) subtrees */
	switch (offsets[0]) {
	default:
2347
		nr = i_data[EXT4_IND_BLOCK];
2348
		if (nr) {
2349 2350
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
2351
		}
2352 2353
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
2354
		if (nr) {
2355 2356
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
2357
		}
2358 2359
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
2360
		if (nr) {
2361 2362
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
2363
		}
2364
	case EXT4_TIND_BLOCK:
2365 2366 2367
		;
	}

2368
	ext4_discard_reservation(inode);
2369 2370

	mutex_unlock(&ei->truncate_mutex);
K
Kalpak Shah 已提交
2371
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
2372
	ext4_mark_inode_dirty(handle, inode);
2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384

	/*
	 * In a multi-transaction truncate, we only make the final transaction
	 * synchronous
	 */
	if (IS_SYNC(inode))
		handle->h_sync = 1;
out_stop:
	/*
	 * If this was a simple ftruncate(), and the file will remain alive
	 * then we need to clear up the orphan record which we created above.
	 * However, if this was a real unlink then we were called by
2385
	 * ext4_delete_inode(), and we allow that function to clean up the
2386 2387 2388
	 * orphan info for us.
	 */
	if (inode->i_nlink)
2389
		ext4_orphan_del(handle, inode);
2390

2391
	ext4_journal_stop(handle);
2392 2393
}

2394 2395
static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
		unsigned long ino, struct ext4_iloc *iloc)
2396 2397 2398
{
	unsigned long desc, group_desc, block_group;
	unsigned long offset;
2399
	ext4_fsblk_t block;
2400
	struct buffer_head *bh;
2401
	struct ext4_group_desc * gdp;
2402

2403
	if (!ext4_valid_inum(sb, ino)) {
2404 2405 2406 2407 2408 2409 2410 2411
		/*
		 * This error is already checked for in namei.c unless we are
		 * looking at an NFS filehandle, in which case no error
		 * report is needed
		 */
		return 0;
	}

2412 2413 2414
	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
	if (block_group >= EXT4_SB(sb)->s_groups_count) {
		ext4_error(sb,"ext4_get_inode_block","group >= groups count");
2415 2416 2417
		return 0;
	}
	smp_rmb();
2418 2419 2420
	group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
	desc = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
	bh = EXT4_SB(sb)->s_group_desc[group_desc];
2421
	if (!bh) {
2422
		ext4_error (sb, "ext4_get_inode_block",
2423 2424 2425 2426
			    "Descriptor not loaded");
		return 0;
	}

2427 2428
	gdp = (struct ext4_group_desc *)((__u8 *)bh->b_data +
		desc * EXT4_DESC_SIZE(sb));
2429 2430 2431
	/*
	 * Figure out the offset within the block group inode table
	 */
2432 2433
	offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
		EXT4_INODE_SIZE(sb);
2434 2435
	block = ext4_inode_table(sb, gdp) +
		(offset >> EXT4_BLOCK_SIZE_BITS(sb));
2436 2437

	iloc->block_group = block_group;
2438
	iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
2439 2440 2441 2442
	return block;
}

/*
2443
 * ext4_get_inode_loc returns with an extra refcount against the inode's
2444 2445 2446 2447
 * underlying buffer_head on success. If 'in_mem' is true, we have all
 * data in memory that is needed to recreate the on-disk version of this
 * inode.
 */
2448 2449
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
2450
{
2451
	ext4_fsblk_t block;
2452 2453
	struct buffer_head *bh;

2454
	block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2455 2456 2457 2458 2459
	if (!block)
		return -EIO;

	bh = sb_getblk(inode->i_sb, block);
	if (!bh) {
2460
		ext4_error (inode->i_sb, "ext4_get_inode_loc",
2461
				"unable to read inode block - "
2462
				"inode=%lu, block=%llu",
2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480
				 inode->i_ino, block);
		return -EIO;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
		if (buffer_uptodate(bh)) {
			/* someone brought it uptodate while we waited */
			unlock_buffer(bh);
			goto has_buffer;
		}

		/*
		 * If we have all information of the inode in memory and this
		 * is the only valid inode in the block, we need not read the
		 * block.
		 */
		if (in_mem) {
			struct buffer_head *bitmap_bh;
2481
			struct ext4_group_desc *desc;
2482 2483 2484 2485 2486 2487
			int inodes_per_buffer;
			int inode_offset, i;
			int block_group;
			int start;

			block_group = (inode->i_ino - 1) /
2488
					EXT4_INODES_PER_GROUP(inode->i_sb);
2489
			inodes_per_buffer = bh->b_size /
2490
				EXT4_INODE_SIZE(inode->i_sb);
2491
			inode_offset = ((inode->i_ino - 1) %
2492
					EXT4_INODES_PER_GROUP(inode->i_sb));
2493 2494 2495
			start = inode_offset & ~(inodes_per_buffer - 1);

			/* Is the inode bitmap in cache? */
2496
			desc = ext4_get_group_desc(inode->i_sb,
2497 2498 2499 2500 2501
						block_group, NULL);
			if (!desc)
				goto make_io;

			bitmap_bh = sb_getblk(inode->i_sb,
2502
				ext4_inode_bitmap(inode->i_sb, desc));
2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517
			if (!bitmap_bh)
				goto make_io;

			/*
			 * If the inode bitmap isn't in cache then the
			 * optimisation may end up performing two reads instead
			 * of one, so skip it.
			 */
			if (!buffer_uptodate(bitmap_bh)) {
				brelse(bitmap_bh);
				goto make_io;
			}
			for (i = start; i < start + inodes_per_buffer; i++) {
				if (i == inode_offset)
					continue;
2518
				if (ext4_test_bit(i, bitmap_bh->b_data))
2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541
					break;
			}
			brelse(bitmap_bh);
			if (i == start + inodes_per_buffer) {
				/* all other inodes are free, so skip I/O */
				memset(bh->b_data, 0, bh->b_size);
				set_buffer_uptodate(bh);
				unlock_buffer(bh);
				goto has_buffer;
			}
		}

make_io:
		/*
		 * There are other valid inodes in the buffer, this inode
		 * has in-inode xattrs, or we don't have this inode in memory.
		 * Read the block from disk.
		 */
		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ_META, bh);
		wait_on_buffer(bh);
		if (!buffer_uptodate(bh)) {
2542
			ext4_error(inode->i_sb, "ext4_get_inode_loc",
2543
					"unable to read inode block - "
2544
					"inode=%lu, block=%llu",
2545 2546 2547 2548 2549 2550 2551 2552 2553 2554
					inode->i_ino, block);
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

2555
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
2556 2557
{
	/* We have all inode data except xattrs in memory here. */
2558 2559
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
2560 2561
}

2562
void ext4_set_inode_flags(struct inode *inode)
2563
{
2564
	unsigned int flags = EXT4_I(inode)->i_flags;
2565 2566

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2567
	if (flags & EXT4_SYNC_FL)
2568
		inode->i_flags |= S_SYNC;
2569
	if (flags & EXT4_APPEND_FL)
2570
		inode->i_flags |= S_APPEND;
2571
	if (flags & EXT4_IMMUTABLE_FL)
2572
		inode->i_flags |= S_IMMUTABLE;
2573
	if (flags & EXT4_NOATIME_FL)
2574
		inode->i_flags |= S_NOATIME;
2575
	if (flags & EXT4_DIRSYNC_FL)
2576 2577 2578
		inode->i_flags |= S_DIRSYNC;
}

2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597
/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
void ext4_get_inode_flags(struct ext4_inode_info *ei)
{
	unsigned int flags = ei->vfs_inode.i_flags;

	ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
			EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
	if (flags & S_SYNC)
		ei->i_flags |= EXT4_SYNC_FL;
	if (flags & S_APPEND)
		ei->i_flags |= EXT4_APPEND_FL;
	if (flags & S_IMMUTABLE)
		ei->i_flags |= EXT4_IMMUTABLE_FL;
	if (flags & S_NOATIME)
		ei->i_flags |= EXT4_NOATIME_FL;
	if (flags & S_DIRSYNC)
		ei->i_flags |= EXT4_DIRSYNC_FL;
}

2598
void ext4_read_inode(struct inode * inode)
2599
{
2600 2601 2602
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
	struct ext4_inode_info *ei = EXT4_I(inode);
2603 2604 2605
	struct buffer_head *bh;
	int block;

2606 2607 2608
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
2609 2610 2611
#endif
	ei->i_block_alloc_info = NULL;

2612
	if (__ext4_get_inode_loc(inode, &iloc, 0))
2613 2614
		goto bad_inode;
	bh = iloc.bh;
2615
	raw_inode = ext4_raw_inode(&iloc);
2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635
	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
	inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
	if(!(test_opt (inode->i_sb, NO_UID32))) {
		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
	}
	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
	inode->i_size = le32_to_cpu(raw_inode->i_size);

	ei->i_state = 0;
	ei->i_dir_start_lookup = 0;
	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
	/* We now have enough fields to check if the inode was active or not.
	 * This is needed because nfsd might try to access dead inodes
	 * the test is that same one that e2fsck uses
	 * NeilBrown 1999oct15
	 */
	if (inode->i_nlink == 0) {
		if (inode->i_mode == 0 ||
2636
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647
			/* this inode is deleted */
			brelse (bh);
			goto bad_inode;
		}
		/* The only unlinked inodes we let through here have
		 * valid i_mode and are being read by the orphan
		 * recovery code: that's fine, we're about to complete
		 * the process of deleting those. */
	}
	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2648
#ifdef EXT4_FRAGMENTS
2649 2650 2651 2652 2653
	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
	ei->i_frag_no = raw_inode->i_frag;
	ei->i_frag_size = raw_inode->i_fsize;
#endif
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2654 2655
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
2656 2657
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670
	if (!S_ISREG(inode->i_mode)) {
		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
	} else {
		inode->i_size |=
			((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
	}
	ei->i_disksize = inode->i_size;
	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
	ei->i_block_group = iloc.block_group;
	/*
	 * NOTE! The in-memory inode i_data array is in little-endian order
	 * even on big-endian machines: we do NOT byteswap the block numbers!
	 */
2671
	for (block = 0; block < EXT4_N_BLOCKS; block++)
2672 2673 2674
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

2675 2676
	if (inode->i_ino >= EXT4_FIRST_INO(inode->i_sb) + 1 &&
	    EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
2677 2678
		/*
		 * When mke2fs creates big inodes it does not zero out
2679
		 * the unused bytes above EXT4_GOOD_OLD_INODE_SIZE,
2680 2681 2682
		 * so ignore those first few inodes.
		 */
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2683
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2684 2685
		    EXT4_INODE_SIZE(inode->i_sb)) {
			brelse (bh);
2686
			goto bad_inode;
2687
		}
2688 2689
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
2690 2691
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
2692 2693
		} else {
			__le32 *magic = (void *)raw_inode +
2694
					EXT4_GOOD_OLD_INODE_SIZE +
2695
					ei->i_extra_isize;
2696 2697
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
2698 2699 2700 2701
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
2702 2703 2704 2705 2706
	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);

2707
	if (S_ISREG(inode->i_mode)) {
2708 2709 2710
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
2711
	} else if (S_ISDIR(inode->i_mode)) {
2712 2713
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
2714
	} else if (S_ISLNK(inode->i_mode)) {
2715 2716
		if (ext4_inode_is_fast_symlink(inode))
			inode->i_op = &ext4_fast_symlink_inode_operations;
2717
		else {
2718 2719
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
2720 2721
		}
	} else {
2722
		inode->i_op = &ext4_special_inode_operations;
2723 2724 2725 2726 2727 2728 2729 2730
		if (raw_inode->i_block[0])
			init_special_inode(inode, inode->i_mode,
			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
		else
			init_special_inode(inode, inode->i_mode,
			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
	}
	brelse (iloc.bh);
2731
	ext4_set_inode_flags(inode);
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745
	return;

bad_inode:
	make_bad_inode(inode);
	return;
}

/*
 * Post the struct inode info into an on-disk inode location in the
 * buffer-cache.  This gobbles the caller's reference to the
 * buffer_head in the inode location struct.
 *
 * The caller must have write access to iloc->bh.
 */
2746
static int ext4_do_update_inode(handle_t *handle,
2747
				struct inode *inode,
2748
				struct ext4_iloc *iloc)
2749
{
2750 2751
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
2752 2753 2754 2755 2756
	struct buffer_head *bh = iloc->bh;
	int err = 0, rc, block;

	/* For fields not not tracking in the in-memory inode,
	 * initialise them to zero for new inodes. */
2757 2758
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2759

2760
	ext4_get_inode_flags(ei);
2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
	if(!(test_opt(inode->i_sb, NO_UID32))) {
		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
/*
 * Fix up interoperability with old kernels. Otherwise, old inodes get
 * re-used with the upper 16 bits of the uid/gid intact
 */
		if(!ei->i_dtime) {
			raw_inode->i_uid_high =
				cpu_to_le16(high_16_bits(inode->i_uid));
			raw_inode->i_gid_high =
				cpu_to_le16(high_16_bits(inode->i_gid));
		} else {
			raw_inode->i_uid_high = 0;
			raw_inode->i_gid_high = 0;
		}
	} else {
		raw_inode->i_uid_low =
			cpu_to_le16(fs_high2lowuid(inode->i_uid));
		raw_inode->i_gid_low =
			cpu_to_le16(fs_high2lowgid(inode->i_gid));
		raw_inode->i_uid_high = 0;
		raw_inode->i_gid_high = 0;
	}
	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
	raw_inode->i_size = cpu_to_le32(ei->i_disksize);
K
Kalpak Shah 已提交
2788 2789 2790 2791 2792 2793

	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);

2794 2795 2796
	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
2797
#ifdef EXT4_FRAGMENTS
2798 2799 2800 2801
	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
	raw_inode->i_frag = ei->i_frag_no;
	raw_inode->i_fsize = ei->i_frag_size;
#endif
2802 2803
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
2804 2805
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
2806 2807 2808 2809 2810 2811 2812 2813
	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
	if (!S_ISREG(inode->i_mode)) {
		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
	} else {
		raw_inode->i_size_high =
			cpu_to_le32(ei->i_disksize >> 32);
		if (ei->i_disksize > 0x7fffffffULL) {
			struct super_block *sb = inode->i_sb;
2814 2815 2816 2817
			if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
			    EXT4_SB(sb)->s_es->s_rev_level ==
					cpu_to_le32(EXT4_GOOD_OLD_REV)) {
2818 2819 2820
			       /* If this is the first large file
				* created, add a flag to the superblock.
				*/
2821 2822
				err = ext4_journal_get_write_access(handle,
						EXT4_SB(sb)->s_sbh);
2823 2824
				if (err)
					goto out_brelse;
2825 2826 2827
				ext4_update_dynamic_rev(sb);
				EXT4_SET_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
2828 2829
				sb->s_dirt = 1;
				handle->h_sync = 1;
2830 2831
				err = ext4_journal_dirty_metadata(handle,
						EXT4_SB(sb)->s_sbh);
2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846
			}
		}
	}
	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
		if (old_valid_dev(inode->i_rdev)) {
			raw_inode->i_block[0] =
				cpu_to_le32(old_encode_dev(inode->i_rdev));
			raw_inode->i_block[1] = 0;
		} else {
			raw_inode->i_block[0] = 0;
			raw_inode->i_block[1] =
				cpu_to_le32(new_encode_dev(inode->i_rdev));
			raw_inode->i_block[2] = 0;
		}
2847
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
2848 2849 2850 2851 2852
		raw_inode->i_block[block] = ei->i_data[block];

	if (ei->i_extra_isize)
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);

2853 2854
	BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
	rc = ext4_journal_dirty_metadata(handle, bh);
2855 2856
	if (!err)
		err = rc;
2857
	ei->i_state &= ~EXT4_STATE_NEW;
2858 2859 2860

out_brelse:
	brelse (bh);
2861
	ext4_std_error(inode->i_sb, err);
2862 2863 2864 2865
	return err;
}

/*
2866
 * ext4_write_inode()
2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882
 *
 * We are called from a few places:
 *
 * - Within generic_file_write() for O_SYNC files.
 *   Here, there will be no transaction running. We wait for any running
 *   trasnaction to commit.
 *
 * - Within sys_sync(), kupdate and such.
 *   We wait on commit, if tol to.
 *
 * - Within prune_icache() (PF_MEMALLOC == true)
 *   Here we simply return.  We can't afford to block kswapd on the
 *   journal commit.
 *
 * In all cases it is actually safe for us to return without doing anything,
 * because the inode has been copied into a raw inode buffer in
2883
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899
 * knfsd.
 *
 * Note that we are absolutely dependent upon all inode dirtiers doing the
 * right thing: they *must* call mark_inode_dirty() after dirtying info in
 * which we are interested.
 *
 * It would be a bug for them to not do this.  The code:
 *
 *	mark_inode_dirty(inode)
 *	stuff();
 *	inode->i_size = expr;
 *
 * is in error because a kswapd-driven write_inode() could occur while
 * `stuff()' is running, and the new i_size will be lost.  Plus the inode
 * will no longer be on the superblock's dirty inode list.
 */
2900
int ext4_write_inode(struct inode *inode, int wait)
2901 2902 2903 2904
{
	if (current->flags & PF_MEMALLOC)
		return 0;

2905
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
2906
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
2907 2908 2909 2910 2911 2912 2913
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

2914
	return ext4_force_commit(inode->i_sb);
2915 2916 2917
}

/*
2918
 * ext4_setattr()
2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933
 *
 * Called from notify_change.
 *
 * We want to trap VFS attempts to truncate the file as soon as
 * possible.  In particular, we want to make sure that when the VFS
 * shrinks i_size, we put the inode on the orphan list and modify
 * i_disksize immediately, so that during the subsequent flushing of
 * dirty pages and freeing of disk blocks, we can guarantee that any
 * commit will leave the blocks being flushed in an unused state on
 * disk.  (On recovery, the inode will get truncated and the blocks will
 * be freed, so we have a strong guarantee that no future commit will
 * leave these blocks visible to the user.)
 *
 * Called with inode->sem down.
 */
2934
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949
{
	struct inode *inode = dentry->d_inode;
	int error, rc = 0;
	const unsigned int ia_valid = attr->ia_valid;

	error = inode_change_ok(inode, attr);
	if (error)
		return error;

	if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
		(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
		handle_t *handle;

		/* (user+group)*(old+new) structure, inode write (sb,
		 * inode block, ? - but truncate inode update has it) */
2950 2951
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
2952 2953 2954 2955 2956 2957
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
		if (error) {
2958
			ext4_journal_stop(handle);
2959 2960 2961 2962 2963 2964 2965 2966
			return error;
		}
		/* Update corresponding info in inode so that everything is in
		 * one transaction */
		if (attr->ia_valid & ATTR_UID)
			inode->i_uid = attr->ia_uid;
		if (attr->ia_valid & ATTR_GID)
			inode->i_gid = attr->ia_gid;
2967 2968
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
2969 2970 2971 2972 2973 2974
	}

	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

2975
		handle = ext4_journal_start(inode, 3);
2976 2977 2978 2979 2980
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

2981 2982 2983
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
2984 2985
		if (!error)
			error = rc;
2986
		ext4_journal_stop(handle);
2987 2988 2989 2990
	}

	rc = inode_setattr(inode, attr);

2991
	/* If inode_setattr's call to ext4_truncate failed to get a
2992 2993 2994
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
2995
		ext4_orphan_del(NULL, inode);
2996 2997

	if (!rc && (ia_valid & ATTR_MODE))
2998
		rc = ext4_acl_chmod(inode);
2999 3000

err_out:
3001
	ext4_std_error(inode->i_sb, error);
3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019
	if (!error)
		error = rc;
	return error;
}


/*
 * How many blocks doth make a writepage()?
 *
 * With N blocks per page, it may be:
 * N data blocks
 * 2 indirect block
 * 2 dindirect
 * 1 tindirect
 * N+5 bitmap blocks (from the above)
 * N+5 group descriptor summary blocks
 * 1 inode block
 * 1 superblock.
3020
 * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
3021
 *
3022
 * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034
 *
 * With ordered or writeback data it's the same, less the N data blocks.
 *
 * If the inode's direct blocks can hold an integral number of pages then a
 * page cannot straddle two indirect blocks, and we can only touch one indirect
 * and dindirect block, and the "5" above becomes "3".
 *
 * This still overestimates under most circumstances.  If we were to pass the
 * start and end offsets in here as well we could do block_to_path() on each
 * block and work out the exact number of indirects which are touched.  Pah.
 */

A
Alex Tomas 已提交
3035
int ext4_writepage_trans_blocks(struct inode *inode)
3036
{
3037 3038
	int bpp = ext4_journal_blocks_per_page(inode);
	int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
3039 3040
	int ret;

A
Alex Tomas 已提交
3041 3042 3043
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
		return ext4_ext_writepage_trans_blocks(inode, bpp);

3044
	if (ext4_should_journal_data(inode))
3045 3046 3047 3048 3049 3050 3051
		ret = 3 * (bpp + indirects) + 2;
	else
		ret = 2 * (bpp + indirects) + 2;

#ifdef CONFIG_QUOTA
	/* We know that structure was already allocated during DQUOT_INIT so
	 * we will be updating only the data blocks + inodes */
3052
	ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
3053 3054 3055 3056 3057 3058
#endif

	return ret;
}

/*
3059
 * The caller must have previously called ext4_reserve_inode_write().
3060 3061
 * Give this, we know that the caller already has write access to iloc->bh.
 */
3062 3063
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
3064 3065 3066 3067 3068 3069
{
	int err = 0;

	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

3070
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
3071
	err = ext4_do_update_inode(handle, inode, iloc);
3072 3073 3074 3075 3076 3077 3078 3079 3080 3081
	put_bh(iloc->bh);
	return err;
}

/*
 * On success, We end up with an outstanding reference count against
 * iloc->bh.  This _must_ be cleaned up later.
 */

int
3082 3083
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
3084 3085 3086
{
	int err = 0;
	if (handle) {
3087
		err = ext4_get_inode_loc(inode, iloc);
3088 3089
		if (!err) {
			BUFFER_TRACE(iloc->bh, "get_write_access");
3090
			err = ext4_journal_get_write_access(handle, iloc->bh);
3091 3092 3093 3094 3095 3096
			if (err) {
				brelse(iloc->bh);
				iloc->bh = NULL;
			}
		}
	}
3097
	ext4_std_error(inode->i_sb, err);
3098 3099 3100
	return err;
}

3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133
/*
 * Expand an inode by new_extra_isize bytes.
 * Returns 0 on success or negative error number on failure.
 */
int ext4_expand_extra_isize(struct inode *inode, unsigned int new_extra_isize,
			struct ext4_iloc iloc, handle_t *handle)
{
	struct ext4_inode *raw_inode;
	struct ext4_xattr_ibody_header *header;
	struct ext4_xattr_entry *entry;

	if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
		return 0;

	raw_inode = ext4_raw_inode(&iloc);

	header = IHDR(inode, raw_inode);
	entry = IFIRST(header);

	/* No extended attributes present */
	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
		header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
			new_extra_isize);
		EXT4_I(inode)->i_extra_isize = new_extra_isize;
		return 0;
	}

	/* try to expand with EAs present */
	return ext4_expand_extra_isize_ea(inode, new_extra_isize,
					  raw_inode, handle);
}

3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154
/*
 * What we do here is to mark the in-core inode as clean with respect to inode
 * dirtiness (it may still be data-dirty).
 * This means that the in-core inode may be reaped by prune_icache
 * without having to perform any I/O.  This is a very good thing,
 * because *any* task may call prune_icache - even ones which
 * have a transaction open against a different journal.
 *
 * Is this cheating?  Not really.  Sure, we haven't written the
 * inode out, but prune_icache isn't a user-visible syncing function.
 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
 * we start and wait on commits.
 *
 * Is this efficient/effective?  Well, we're being nice to the system
 * by cleaning up our inodes proactively so they can be reaped
 * without I/O.  But we are potentially leaving up to five seconds'
 * worth of inodes floating about which prune_icache wants us to
 * write out.  One way to fix that would be to get prune_icache()
 * to do a write_super() to free up some memory.  It has the desired
 * effect.
 */
3155
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
3156
{
3157
	struct ext4_iloc iloc;
3158 3159 3160
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
3161 3162

	might_sleep();
3163
	err = ext4_reserve_inode_write(handle, inode, &iloc);
3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189
	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
	    !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
		/*
		 * We need extra buffer credits since we may write into EA block
		 * with this same handle. If journal_extend fails, then it will
		 * only result in a minor loss of functionality for that inode.
		 * If this is felt to be critical, then e2fsck should be run to
		 * force a large enough s_min_extra_isize.
		 */
		if ((jbd2_journal_extend(handle,
			     EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
			ret = ext4_expand_extra_isize(inode,
						      sbi->s_want_extra_isize,
						      iloc, handle);
			if (ret) {
				EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
				if (mnt_count != sbi->s_es->s_mnt_count) {
					ext4_warning(inode->i_sb, __FUNCTION__,
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
					mnt_count = sbi->s_es->s_mnt_count;
				}
			}
		}
	}
3190
	if (!err)
3191
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
3192 3193 3194 3195
	return err;
}

/*
3196
 * ext4_dirty_inode() is called from __mark_inode_dirty()
3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208
 *
 * We're really interested in the case where a file is being extended.
 * i_size has been changed by generic_commit_write() and we thus need
 * to include the updated inode in the current transaction.
 *
 * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
 * are allocated to the file.
 *
 * If the inode is marked synchronous, we don't honour that here - doing
 * so would cause a commit on atime updates, which we don't bother doing.
 * We handle synchronous inodes at the highest possible level.
 */
3209
void ext4_dirty_inode(struct inode *inode)
3210
{
3211
	handle_t *current_handle = ext4_journal_current_handle();
3212 3213
	handle_t *handle;

3214
	handle = ext4_journal_start(inode, 2);
3215 3216 3217 3218 3219 3220 3221 3222 3223 3224
	if (IS_ERR(handle))
		goto out;
	if (current_handle &&
		current_handle->h_transaction != handle->h_transaction) {
		/* This task has a transaction open against a different fs */
		printk(KERN_EMERG "%s: transactions do not match!\n",
		       __FUNCTION__);
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
3225
		ext4_mark_inode_dirty(handle, inode);
3226
	}
3227
	ext4_journal_stop(handle);
3228 3229 3230 3231 3232 3233 3234 3235
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
3236
 * ext4_reserve_inode_write, this leaves behind no bh reference and
3237 3238 3239
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
3240
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
3241
{
3242
	struct ext4_iloc iloc;
3243 3244 3245

	int err = 0;
	if (handle) {
3246
		err = ext4_get_inode_loc(inode, &iloc);
3247 3248
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
3249
			err = jbd2_journal_get_write_access(handle, iloc.bh);
3250
			if (!err)
3251
				err = ext4_journal_dirty_metadata(handle,
3252 3253 3254 3255
								  iloc.bh);
			brelse(iloc.bh);
		}
	}
3256
	ext4_std_error(inode->i_sb, err);
3257 3258 3259 3260
	return err;
}
#endif

3261
int ext4_change_inode_journal_flag(struct inode *inode, int val)
3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276
{
	journal_t *journal;
	handle_t *handle;
	int err;

	/*
	 * We have to be very careful here: changing a data block's
	 * journaling status dynamically is dangerous.  If we write a
	 * data block to the journal, change the status and then delete
	 * that block, we risk forgetting to revoke the old log record
	 * from the journal and so a subsequent replay can corrupt data.
	 * So, first we make sure that the journal is empty and that
	 * nobody is changing anything.
	 */

3277
	journal = EXT4_JOURNAL(inode);
3278
	if (is_journal_aborted(journal))
3279 3280
		return -EROFS;

3281 3282
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
3283 3284 3285 3286 3287 3288 3289 3290 3291 3292

	/*
	 * OK, there are no updates running now, and all cached data is
	 * synced to disk.  We are now in a completely consistent state
	 * which doesn't have anything in the journal, and we know that
	 * no filesystem updates are running, so it is safe to modify
	 * the inode's in-core data-journaling state flag now.
	 */

	if (val)
3293
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
3294
	else
3295 3296
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
3297

3298
	jbd2_journal_unlock_updates(journal);
3299 3300 3301

	/* Finally we can mark the inode as dirty. */

3302
	handle = ext4_journal_start(inode, 1);
3303 3304 3305
	if (IS_ERR(handle))
		return PTR_ERR(handle);

3306
	err = ext4_mark_inode_dirty(handle, inode);
3307
	handle->h_sync = 1;
3308 3309
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
3310 3311 3312

	return err;
}