inode.c 143.0 KB
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/*
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 *  linux/fs/ext4/inode.c
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 *
 * 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)
 *
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 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
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 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
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#include <linux/jbd2.h>
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#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>
35
#include <linux/pagevec.h>
36 37 38
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
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#include "ext4_jbd2.h"
40 41
#include "xattr.h"
#include "acl.h"
42
#include "ext4_extents.h"
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44 45
#define MPAGE_DA_EXTENT_TAIL 0x01

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static inline int ext4_begin_ordered_truncate(struct inode *inode,
					      loff_t new_size)
{
	return jbd2_journal_begin_ordered_truncate(&EXT4_I(inode)->jinode,
						   new_size);
}

53 54
static void ext4_invalidatepage(struct page *page, unsigned long offset);

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/*
 * Test whether an inode is a fast symlink.
 */
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static int ext4_inode_is_fast_symlink(struct inode *inode)
59
{
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	int ea_blocks = EXT4_I(inode)->i_file_acl ?
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		(inode->i_sb->s_blocksize >> 9) : 0;

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

/*
67
 * The ext4 forget function must perform a revoke if we are freeing data
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 * 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.
 */
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int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
			struct buffer_head *bh, ext4_fsblk_t blocknr)
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{
	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. */

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	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
	    (!is_metadata && !ext4_should_journal_data(inode))) {
96
		if (bh) {
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			BUFFER_TRACE(bh, "call jbd2_journal_forget");
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			return ext4_journal_forget(handle, bh);
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		}
		return 0;
	}

	/*
	 * data!=journal && (is_metadata || should_journal_data(inode))
	 */
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	BUFFER_TRACE(bh, "call ext4_journal_revoke");
	err = ext4_journal_revoke(handle, blocknr, bh);
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	if (err)
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		ext4_abort(inode->i_sb, __func__,
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			   "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)
{
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	ext4_lblk_t needed;
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	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
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	 * like a regular file for ext4 to try to delete it.  Things
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	 * 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. */
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	if (needed > EXT4_MAX_TRANS_DATA)
		needed = EXT4_MAX_TRANS_DATA;
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	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
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}

/*
 * 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;

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	result = ext4_journal_start(inode, blocks_for_truncate(inode));
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	if (!IS_ERR(result))
		return result;

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	ext4_std_error(inode->i_sb, PTR_ERR(result));
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	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)
{
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	if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
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		return 0;
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	if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
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		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.
 */
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static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
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{
	jbd_debug(2, "restarting handle %p\n", handle);
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	return ext4_journal_restart(handle, blocks_for_truncate(inode));
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}

/*
 * Called at the last iput() if i_nlink is zero.
 */
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void ext4_delete_inode(struct inode *inode)
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{
	handle_t *handle;
196
	int err;
197

198 199
	if (ext4_should_order_data(inode))
		ext4_begin_ordered_truncate(inode, 0);
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	truncate_inode_pages(&inode->i_data, 0);

	if (is_bad_inode(inode))
		goto no_delete;

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	handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
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	if (IS_ERR(handle)) {
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		ext4_std_error(inode->i_sb, PTR_ERR(handle));
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		/*
		 * 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.
		 */
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		ext4_orphan_del(NULL, inode);
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		goto no_delete;
	}

	if (IS_SYNC(inode))
		handle->h_sync = 1;
	inode->i_size = 0;
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	err = ext4_mark_inode_dirty(handle, inode);
	if (err) {
		ext4_warning(inode->i_sb, __func__,
			     "couldn't mark inode dirty (err %d)", err);
		goto stop_handle;
	}
226
	if (inode->i_blocks)
227
		ext4_truncate(inode);
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	/*
	 * ext4_ext_truncate() doesn't reserve any slop when it
	 * restarts journal transactions; therefore there may not be
	 * enough credits left in the handle to remove the inode from
	 * the orphan list and set the dtime field.
	 */
	if (handle->h_buffer_credits < 3) {
		err = ext4_journal_extend(handle, 3);
		if (err > 0)
			err = ext4_journal_restart(handle, 3);
		if (err != 0) {
			ext4_warning(inode->i_sb, __func__,
				     "couldn't extend journal (err %d)", err);
		stop_handle:
			ext4_journal_stop(handle);
			goto no_delete;
		}
	}

248
	/*
249
	 * Kill off the orphan record which ext4_truncate created.
250
	 * AKPM: I think this can be inside the above `if'.
251
	 * Note that ext4_orphan_del() has to be able to cope with the
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	 * deletion of a non-existent orphan - this is because we don't
253
	 * know if ext4_truncate() actually created an orphan record.
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	 * (Well, we could do this if we need to, but heck - it works)
	 */
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	ext4_orphan_del(handle, inode);
	EXT4_I(inode)->i_dtime	= get_seconds();
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	/*
	 * 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.
	 */
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	if (ext4_mark_inode_dirty(handle, inode))
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		/* If that failed, just do the required in-core inode clear. */
		clear_inode(inode);
	else
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		ext4_free_inode(handle, inode);
	ext4_journal_stop(handle);
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	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;
}

/**
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 *	ext4_block_to_path - parse the block number into array of offsets
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 *	@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
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 *	@boundary: set this non-zero if the referred-to block is likely to be
 *	       followed (on disk) by an indirect block.
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 *
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 *	To store the locations of file's data ext4 uses a data structure common
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 *	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.
 */

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static int ext4_block_to_path(struct inode *inode,
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			ext4_lblk_t i_block,
			ext4_lblk_t offsets[4], int *boundary)
323
{
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	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,
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		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;
	int final = 0;

	if (i_block < 0) {
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		ext4_warning(inode->i_sb, "ext4_block_to_path", "block < 0");
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	} else if (i_block < direct_blocks) {
		offsets[n++] = i_block;
		final = direct_blocks;
337
	} else if ((i_block -= direct_blocks) < indirect_blocks) {
338
		offsets[n++] = EXT4_IND_BLOCK;
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		offsets[n++] = i_block;
		final = ptrs;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
342
		offsets[n++] = EXT4_DIND_BLOCK;
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		offsets[n++] = i_block >> ptrs_bits;
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
347
		offsets[n++] = EXT4_TIND_BLOCK;
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		offsets[n++] = i_block >> (ptrs_bits * 2);
		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
		offsets[n++] = i_block & (ptrs - 1);
		final = ptrs;
	} else {
353
		ext4_warning(inode->i_sb, "ext4_block_to_path",
354
				"block %lu > max",
355 356
				i_block + direct_blocks +
				indirect_blocks + double_blocks);
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	}
	if (boundary)
		*boundary = final - 1 - (i_block & (ptrs - 1));
	return n;
}

/**
364
 *	ext4_get_branch - read the chain of indirect blocks leading to data
365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388
 *	@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 reads all @depth-1 indirect blocks successfully and finds
 *	the whole chain, all way to the data (returns %NULL, *err == 0).
389 390
 *
 *      Need to be called with
391
 *      down_read(&EXT4_I(inode)->i_data_sem)
392
 */
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static Indirect *ext4_get_branch(struct inode *inode, int depth,
				 ext4_lblk_t  *offsets,
395 396 397 398 399 400 401 402
				 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 */
403
	add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
404 405 406 407 408 409
	if (!p->key)
		goto no_block;
	while (--depth) {
		bh = sb_bread(sb, le32_to_cpu(p->key));
		if (!bh)
			goto failure;
410
		add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
411 412 413 414 415 416 417 418 419 420 421 422 423
		/* Reader: end */
		if (!p->key)
			goto no_block;
	}
	return NULL;

failure:
	*err = -EIO;
no_block:
	return p;
}

/**
424
 *	ext4_find_near - find a place for allocation with sufficient locality
425 426 427
 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
428
 *	This function returns the preferred place for block allocation.
429 430 431 432 433 434 435 436 437 438 439 440 441 442
 *	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.
 */
443
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
444
{
445
	struct ext4_inode_info *ei = EXT4_I(inode);
446
	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
447
	__le32 *p;
448
	ext4_fsblk_t bg_start;
449
	ext4_fsblk_t last_block;
450
	ext4_grpblk_t colour;
451 452 453 454 455 456 457 458 459 460 461 462 463 464 465

	/* 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.
	 */
466
	bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
467 468 469 470
	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;

	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
		colour = (current->pid % 16) *
471
			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
472 473
	else
		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
474 475 476 477
	return bg_start + colour;
}

/**
478
 *	ext4_find_goal - find a preferred place for allocation.
479 480 481 482
 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
483
 *	Normally this function find the preferred place for block allocation,
484
 *	returns it.
485
 */
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486
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
487
		Indirect *partial)
488 489
{
	/*
490
	 * XXX need to get goal block from mballoc's data structures
491 492
	 */

493
	return ext4_find_near(inode, partial);
494 495 496
}

/**
497
 *	ext4_blks_to_allocate: Look up the block map and count the number
498 499 500 501 502 503 504 505 506 507
 *	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.
 */
508
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534
		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;
}

/**
535
 *	ext4_alloc_blocks: multiple allocate blocks needed for a branch
536 537 538 539 540 541 542 543
 *	@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
 */
544
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
545 546 547
				ext4_lblk_t iblock, ext4_fsblk_t goal,
				int indirect_blks, int blks,
				ext4_fsblk_t new_blocks[4], int *err)
548 549
{
	int target, i;
550
	unsigned long count = 0, blk_allocated = 0;
551
	int index = 0;
552
	ext4_fsblk_t current_block = 0;
553 554 555 556 557 558 559 560 561 562
	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)
	 */
563 564 565
	/* first we try to allocate the indirect blocks */
	target = indirect_blks;
	while (target > 0) {
566 567
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
568 569
		current_block = ext4_new_meta_blocks(handle, inode,
							goal, &count, err);
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		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}
579 580 581 582 583 584 585 586 587
		if (count > 0) {
			/*
			 * save the new block number
			 * for the first direct block
			 */
			new_blocks[index] = current_block;
			printk(KERN_INFO "%s returned more blocks than "
						"requested\n", __func__);
			WARN_ON(1);
588
			break;
589
		}
590 591
	}

592 593 594 595 596 597
	target = blks - count ;
	blk_allocated = count;
	if (!target)
		goto allocated;
	/* Now allocate data blocks */
	count = target;
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598
	/* allocating blocks for data blocks */
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	current_block = ext4_new_blocks(handle, inode, iblock,
						goal, &count, err);
	if (*err && (target == blks)) {
		/*
		 * if the allocation failed and we didn't allocate
		 * any blocks before
		 */
		goto failed_out;
	}
	if (!*err) {
		if (target == blks) {
		/*
		 * save the new block number
		 * for the first direct block
		 */
			new_blocks[index] = current_block;
		}
		blk_allocated += count;
	}
allocated:
619
	/* total number of blocks allocated for direct blocks */
620
	ret = blk_allocated;
621 622 623
	*err = 0;
	return ret;
failed_out:
624
	for (i = 0; i < index; i++)
625
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
626 627 628 629
	return ret;
}

/**
630
 *	ext4_alloc_branch - allocate and set up a chain of blocks.
631 632 633 634 635 636 637 638 639 640
 *	@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
641
 *	the same format as ext4_get_branch() would do. We are calling it after
642 643
 *	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
644
 *	picture as after the successful ext4_get_block(), except that in one
645 646 647 648 649 650
 *	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
651
 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
652 653
 *	as described above and return 0.
 */
654
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
655 656 657
				ext4_lblk_t iblock, int indirect_blks,
				int *blks, ext4_fsblk_t goal,
				ext4_lblk_t *offsets, Indirect *branch)
658 659 660 661 662 663
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
664 665
	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
666

667
	num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685
				*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");
686
		err = ext4_journal_get_create_access(handle, bh);
687 688 689 690 691 692 693 694 695 696
		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;
697
		if (n == indirect_blks) {
698 699 700 701 702 703 704 705 706 707 708 709 710
			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);

711 712
		BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, bh);
713 714 715 716 717 718 719 720
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
721
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
722
		ext4_journal_forget(handle, branch[i].bh);
723
	}
724
	for (i = 0; i < indirect_blks; i++)
725
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
726

727
	ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
728 729 730 731 732

	return err;
}

/**
733
 * ext4_splice_branch - splice the allocated branch onto inode.
734 735 736
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
737
 *	ext4_alloc_branch)
738 739 740 741 742 743 744 745
 * @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.
 */
746
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
747
			ext4_lblk_t block, Indirect *where, int num, int blks)
748 749 750
{
	int i;
	int err = 0;
751
	ext4_fsblk_t current_block;
752 753 754 755 756 757 758 759

	/*
	 * 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");
760
		err = ext4_journal_get_write_access(handle, where->bh);
761 762 763 764 765 766 767 768 769 770 771 772 773 774
		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++)
775
			*(where->p + i) = cpu_to_le32(current_block++);
776 777 778 779
	}

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

K
Kalpak Shah 已提交
780
	inode->i_ctime = ext4_current_time(inode);
781
	ext4_mark_inode_dirty(handle, inode);
782 783 784 785 786 787 788 789 790

	/* 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
791
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
792 793
		 */
		jbd_debug(5, "splicing indirect only\n");
794 795
		BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, where->bh);
796 797 798 799 800 801 802 803 804 805 806 807 808
		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++) {
809
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
810
		ext4_journal_forget(handle, where[i].bh);
811 812
		ext4_free_blocks(handle, inode,
					le32_to_cpu(where[i-1].key), 1, 0);
813
	}
814
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835

	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.
 *
 * return > 0, # of blocks mapped or allocated.
 * return = 0, if plain lookup failed.
 * return < 0, error case.
836 837 838
 *
 *
 * Need to be called with
839 840
 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
841
 */
842
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
843
		ext4_lblk_t iblock, unsigned long maxblocks,
844 845 846 847
		struct buffer_head *bh_result,
		int create, int extend_disksize)
{
	int err = -EIO;
A
Aneesh Kumar K.V 已提交
848
	ext4_lblk_t offsets[4];
849 850
	Indirect chain[4];
	Indirect *partial;
851
	ext4_fsblk_t goal;
852 853 854
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
855
	struct ext4_inode_info *ei = EXT4_I(inode);
856
	int count = 0;
857
	ext4_fsblk_t first_block = 0;
858
	loff_t disksize;
859 860


A
Alex Tomas 已提交
861
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
862
	J_ASSERT(handle != NULL || create == 0);
A
Aneesh Kumar K.V 已提交
863 864
	depth = ext4_block_to_path(inode, iblock, offsets,
					&blocks_to_boundary);
865 866 867 868

	if (depth == 0)
		goto out;

869
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
870 871 872 873 874 875 876 877

	/* 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) {
878
			ext4_fsblk_t blk;
879 880 881 882 883 884 885 886

			blk = le32_to_cpu(*(chain[depth-1].p + count));

			if (blk == first_block + count)
				count++;
			else
				break;
		}
887
		goto got_it;
888 889 890 891 892 893 894
	}

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

	/*
895
	 * Okay, we need to do block allocation.
896
	*/
897
	goal = ext4_find_goal(inode, iblock, partial);
898 899 900 901 902 903 904 905

	/* 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.
	 */
906
	count = ext4_blks_to_allocate(partial, indirect_blks,
907 908
					maxblocks, blocks_to_boundary);
	/*
909
	 * Block out ext4_truncate while we alter the tree
910
	 */
911 912 913
	err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
					&count, goal,
					offsets + (partial - chain), partial);
914 915

	/*
916
	 * The ext4_splice_branch call will free and forget any buffers
917 918 919 920 921 922
	 * 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)
923
		err = ext4_splice_branch(handle, inode, iblock,
924 925
					partial, indirect_blks, count);
	/*
926
	 * i_disksize growing is protected by i_data_sem.  Don't forget to
927
	 * protect it if you're about to implement concurrent
928
	 * ext4_get_block() -bzzz
929
	*/
930 931 932 933 934 935 936
	if (!err && extend_disksize) {
		disksize = ((loff_t) iblock + count) << inode->i_blkbits;
		if (disksize > i_size_read(inode))
			disksize = i_size_read(inode);
		if (disksize > ei->i_disksize)
			ei->i_disksize = disksize;
	}
937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
	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;
}

959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983
/*
 * Calculate the number of metadata blocks need to reserve
 * to allocate @blocks for non extent file based file
 */
static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
{
	int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
	int ind_blks, dind_blks, tind_blks;

	/* number of new indirect blocks needed */
	ind_blks = (blocks + icap - 1) / icap;

	dind_blks = (ind_blks + icap - 1) / icap;

	tind_blks = 1;

	return ind_blks + dind_blks + tind_blks;
}

/*
 * Calculate the number of metadata blocks need to reserve
 * to allocate given number of blocks
 */
static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
{
984 985 986
	if (!blocks)
		return 0;

987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
		return ext4_ext_calc_metadata_amount(inode, blocks);

	return ext4_indirect_calc_metadata_amount(inode, blocks);
}

static void ext4_da_update_reserve_space(struct inode *inode, int used)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	int total, mdb, mdb_free;

	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	/* recalculate the number of metablocks still need to be reserved */
	total = EXT4_I(inode)->i_reserved_data_blocks - used;
	mdb = ext4_calc_metadata_amount(inode, total);

	/* figure out how many metablocks to release */
	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;

1007 1008 1009 1010 1011 1012 1013 1014 1015
	if (mdb_free) {
		/* Account for allocated meta_blocks */
		mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;

		/* update fs dirty blocks counter */
		percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
		EXT4_I(inode)->i_allocated_meta_blocks = 0;
		EXT4_I(inode)->i_reserved_meta_blocks = mdb;
	}
1016 1017 1018 1019 1020 1021 1022 1023

	/* update per-inode reservations */
	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
	EXT4_I(inode)->i_reserved_data_blocks -= used;

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}

1024
/*
1025 1026
 * The ext4_get_blocks_wrap() function try to look up the requested blocks,
 * and returns if the blocks are already mapped.
1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
 *
 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 * and store the allocated blocks in the result buffer head and mark it
 * mapped.
 *
 * If file type is extents based, it will call ext4_ext_get_blocks(),
 * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
 * based files
 *
 * On success, it returns the number of blocks being mapped or allocate.
 * if create==0 and the blocks are pre-allocated and uninitialized block,
 * the result buffer head is unmapped. If the create ==1, it will make sure
 * the buffer head is mapped.
 *
 * It returns 0 if plain look up failed (blocks have not been allocated), in
 * that casem, buffer head is unmapped
 *
 * It returns the error in case of allocation failure.
 */
1046 1047
int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
			unsigned long max_blocks, struct buffer_head *bh,
1048
			int create, int extend_disksize, int flag)
1049 1050
{
	int retval;
1051 1052 1053

	clear_buffer_mapped(bh);

1054 1055 1056 1057 1058 1059 1060 1061
	/*
	 * Try to see if we can get  the block without requesting
	 * for new file system block.
	 */
	down_read((&EXT4_I(inode)->i_data_sem));
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
				bh, 0, 0);
1062
	} else {
1063 1064
		retval = ext4_get_blocks_handle(handle,
				inode, block, max_blocks, bh, 0, 0);
1065
	}
1066
	up_read((&EXT4_I(inode)->i_data_sem));
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079

	/* If it is only a block(s) look up */
	if (!create)
		return retval;

	/*
	 * Returns if the blocks have already allocated
	 *
	 * Note that if blocks have been preallocated
	 * ext4_ext_get_block() returns th create = 0
	 * with buffer head unmapped.
	 */
	if (retval > 0 && buffer_mapped(bh))
1080 1081 1082
		return retval;

	/*
1083 1084 1085 1086
	 * New blocks allocate and/or writing to uninitialized extent
	 * will possibly result in updating i_data, so we take
	 * the write lock of i_data_sem, and call get_blocks()
	 * with create == 1 flag.
1087 1088
	 */
	down_write((&EXT4_I(inode)->i_data_sem));
1089 1090 1091 1092 1093 1094 1095 1096 1097

	/*
	 * if the caller is from delayed allocation writeout path
	 * we have already reserved fs blocks for allocation
	 * let the underlying get_block() function know to
	 * avoid double accounting
	 */
	if (flag)
		EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1098 1099 1100 1101
	/*
	 * We need to check for EXT4 here because migrate
	 * could have changed the inode type in between
	 */
1102 1103 1104 1105 1106 1107
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
				bh, create, extend_disksize);
	} else {
		retval = ext4_get_blocks_handle(handle, inode, block,
				max_blocks, bh, create, extend_disksize);
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117

		if (retval > 0 && buffer_new(bh)) {
			/*
			 * We allocated new blocks which will result in
			 * i_data's format changing.  Force the migrate
			 * to fail by clearing migrate flags
			 */
			EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
							~EXT4_EXT_MIGRATE;
		}
1118
	}
1119 1120 1121 1122 1123 1124 1125 1126 1127

	if (flag) {
		EXT4_I(inode)->i_delalloc_reserved_flag = 0;
		/*
		 * Update reserved blocks/metadata blocks
		 * after successful block allocation
		 * which were deferred till now
		 */
		if ((retval > 0) && buffer_delay(bh))
1128
			ext4_da_update_reserve_space(inode, retval);
1129 1130
	}

1131
	up_write((&EXT4_I(inode)->i_data_sem));
1132 1133 1134
	return retval;
}

1135 1136 1137
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096

1138 1139
int ext4_get_block(struct inode *inode, sector_t iblock,
		   struct buffer_head *bh_result, int create)
1140
{
1141
	handle_t *handle = ext4_journal_current_handle();
J
Jan Kara 已提交
1142
	int ret = 0, started = 0;
1143
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1144
	int dio_credits;
1145

J
Jan Kara 已提交
1146 1147 1148 1149
	if (create && !handle) {
		/* Direct IO write... */
		if (max_blocks > DIO_MAX_BLOCKS)
			max_blocks = DIO_MAX_BLOCKS;
1150 1151
		dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
		handle = ext4_journal_start(inode, dio_credits);
J
Jan Kara 已提交
1152
		if (IS_ERR(handle)) {
1153
			ret = PTR_ERR(handle);
J
Jan Kara 已提交
1154
			goto out;
1155
		}
J
Jan Kara 已提交
1156
		started = 1;
1157 1158
	}

J
Jan Kara 已提交
1159
	ret = ext4_get_blocks_wrap(handle, inode, iblock,
1160
					max_blocks, bh_result, create, 0, 0);
J
Jan Kara 已提交
1161 1162 1163
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
1164
	}
J
Jan Kara 已提交
1165 1166 1167
	if (started)
		ext4_journal_stop(handle);
out:
1168 1169 1170 1171 1172 1173
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
1174
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1175
				ext4_lblk_t block, int create, int *errp)
1176 1177 1178 1179 1180 1181 1182 1183 1184
{
	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
1185
	err = ext4_get_blocks_wrap(handle, inode, block, 1,
1186
					&dummy, create, 1, 0);
1187
	/*
1188
	 * ext4_get_blocks_handle() returns number of blocks
1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205
	 * 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);
A
Aneesh Kumar K.V 已提交
1206
			J_ASSERT(handle != NULL);
1207 1208 1209 1210 1211

			/*
			 * 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
1212
			 * writes use ext4_get_block instead, so it's not a
1213 1214 1215 1216
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1217
			fatal = ext4_journal_get_create_access(handle, bh);
1218
			if (!fatal && !buffer_uptodate(bh)) {
1219
				memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1220 1221 1222
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1223 1224
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			err = ext4_journal_dirty_metadata(handle, bh);
1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240
			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;
}

1241
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1242
			       ext4_lblk_t block, int create, int *err)
1243
{
1244
	struct buffer_head *bh;
1245

1246
	bh = ext4_getblk(handle, inode, block, create, err);
1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259
	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;
}

1260 1261 1262 1263 1264 1265 1266
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))
1267 1268 1269 1270 1271 1272 1273
{
	struct buffer_head *bh;
	unsigned block_start, block_end;
	unsigned blocksize = head->b_size;
	int err, ret = 0;
	struct buffer_head *next;

1274 1275 1276
	for (bh = head, block_start = 0;
	     ret == 0 && (bh != head || !block_start);
	     block_start = block_end, bh = next)
1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294
	{
		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
1295
 * close off a transaction and start a new one between the ext4_get_block()
1296
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1297 1298
 * prepare_write() is the right place.
 *
1299 1300
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1301 1302 1303 1304
 * 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.
 *
1305
 * By accident, ext4 can be reentered when a transaction is open via
1306 1307 1308 1309 1310 1311
 * 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.
 *
1312
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1313 1314 1315 1316 1317 1318 1319 1320 1321
 * 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;
1322
	return ext4_journal_get_write_access(handle, bh);
1323 1324
}

N
Nick Piggin 已提交
1325 1326 1327
static int ext4_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
1328
{
1329
	struct inode *inode = mapping->host;
1330
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1331 1332
	handle_t *handle;
	int retries = 0;
1333
	struct page *page;
N
Nick Piggin 已提交
1334
 	pgoff_t index;
1335
	unsigned from, to;
N
Nick Piggin 已提交
1336 1337

 	index = pos >> PAGE_CACHE_SHIFT;
1338 1339
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;
1340 1341

retry:
1342 1343 1344 1345
	handle = ext4_journal_start(inode, needed_blocks);
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out;
1346
	}
1347

1348 1349 1350 1351 1352 1353 1354 1355
	page = __grab_cache_page(mapping, index);
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
	*pagep = page;

N
Nick Piggin 已提交
1356 1357 1358 1359
	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
							ext4_get_block);

	if (!ret && ext4_should_journal_data(inode)) {
1360 1361 1362
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
N
Nick Piggin 已提交
1363 1364

	if (ret) {
1365
		unlock_page(page);
1366
		ext4_journal_stop(handle);
1367
		page_cache_release(page);
1368 1369 1370 1371 1372 1373 1374
		/*
		 * block_write_begin may have instantiated a few blocks
		 * outside i_size.  Trim these off again. Don't need
		 * i_size_read because we hold i_mutex.
		 */
		if (pos + len > inode->i_size)
			vmtruncate(inode, inode->i_size);
N
Nick Piggin 已提交
1375 1376
	}

1377
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1378
		goto retry;
1379
out:
1380 1381 1382
	return ret;
}

N
Nick Piggin 已提交
1383 1384
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1385 1386 1387 1388
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1389
	return ext4_journal_dirty_metadata(handle, bh);
1390 1391 1392 1393 1394 1395
}

/*
 * 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().
 *
1396
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1397 1398
 * buffers are managed internally.
 */
N
Nick Piggin 已提交
1399 1400 1401 1402
static int ext4_ordered_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
1403
{
1404
	handle_t *handle = ext4_journal_current_handle();
1405
	struct inode *inode = mapping->host;
1406 1407
	int ret = 0, ret2;

1408
	ret = ext4_jbd2_file_inode(handle, inode);
1409 1410 1411 1412

	if (ret == 0) {
		loff_t new_i_size;

N
Nick Piggin 已提交
1413
		new_i_size = pos + copied;
1414 1415 1416 1417 1418 1419 1420 1421 1422
		if (new_i_size > EXT4_I(inode)->i_disksize) {
			ext4_update_i_disksize(inode, new_i_size);
			/* We need to mark inode dirty even if
			 * new_i_size is less that inode->i_size
			 * bu greater than i_disksize.(hint delalloc)
			 */
			ext4_mark_inode_dirty(handle, inode);
		}

1423
		ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1424
							page, fsdata);
1425 1426 1427
		copied = ret2;
		if (ret2 < 0)
			ret = ret2;
1428
	}
1429
	ret2 = ext4_journal_stop(handle);
1430 1431
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1432 1433

	return ret ? ret : copied;
1434 1435
}

N
Nick Piggin 已提交
1436 1437 1438 1439
static int ext4_writeback_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
1440
{
1441
	handle_t *handle = ext4_journal_current_handle();
1442
	struct inode *inode = mapping->host;
1443 1444 1445
	int ret = 0, ret2;
	loff_t new_i_size;

N
Nick Piggin 已提交
1446
	new_i_size = pos + copied;
1447 1448 1449 1450 1451 1452 1453 1454
	if (new_i_size > EXT4_I(inode)->i_disksize) {
		ext4_update_i_disksize(inode, new_i_size);
		/* We need to mark inode dirty even if
		 * new_i_size is less that inode->i_size
		 * bu greater than i_disksize.(hint delalloc)
		 */
		ext4_mark_inode_dirty(handle, inode);
	}
1455

1456
	ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1457
							page, fsdata);
1458 1459 1460
	copied = ret2;
	if (ret2 < 0)
		ret = ret2;
1461

1462
	ret2 = ext4_journal_stop(handle);
1463 1464
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1465 1466

	return ret ? ret : copied;
1467 1468
}

N
Nick Piggin 已提交
1469 1470 1471 1472
static int ext4_journalled_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
1473
{
1474
	handle_t *handle = ext4_journal_current_handle();
N
Nick Piggin 已提交
1475
	struct inode *inode = mapping->host;
1476 1477
	int ret = 0, ret2;
	int partial = 0;
N
Nick Piggin 已提交
1478
	unsigned from, to;
1479
	loff_t new_i_size;
1480

N
Nick Piggin 已提交
1481 1482 1483 1484 1485 1486 1487 1488
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;

	if (copied < len) {
		if (!PageUptodate(page))
			copied = 0;
		page_zero_new_buffers(page, from+copied, to);
	}
1489 1490

	ret = walk_page_buffers(handle, page_buffers(page), from,
N
Nick Piggin 已提交
1491
				to, &partial, write_end_fn);
1492 1493
	if (!partial)
		SetPageUptodate(page);
1494 1495
	new_i_size = pos + copied;
	if (new_i_size > inode->i_size)
N
Nick Piggin 已提交
1496
		i_size_write(inode, pos+copied);
1497
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1498 1499
	if (new_i_size > EXT4_I(inode)->i_disksize) {
		ext4_update_i_disksize(inode, new_i_size);
1500
		ret2 = ext4_mark_inode_dirty(handle, inode);
1501 1502 1503
		if (!ret)
			ret = ret2;
	}
N
Nick Piggin 已提交
1504

1505
	unlock_page(page);
1506
	ret2 = ext4_journal_stop(handle);
1507 1508
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1509 1510 1511
	page_cache_release(page);

	return ret ? ret : copied;
1512
}
1513 1514 1515

static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
{
A
Aneesh Kumar K.V 已提交
1516
	int retries = 0;
1517 1518 1519 1520 1521 1522 1523 1524
       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
       unsigned long md_needed, mdblocks, total = 0;

	/*
	 * recalculate the amount of metadata blocks to reserve
	 * in order to allocate nrblocks
	 * worse case is one extent per block
	 */
A
Aneesh Kumar K.V 已提交
1525
repeat:
1526 1527 1528 1529 1530 1531 1532 1533
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
	mdblocks = ext4_calc_metadata_amount(inode, total);
	BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);

	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
	total = md_needed + nrblocks;

1534
	if (ext4_claim_free_blocks(sbi, total)) {
1535
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
A
Aneesh Kumar K.V 已提交
1536 1537 1538 1539
		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
			yield();
			goto repeat;
		}
1540 1541 1542 1543 1544 1545 1546 1547 1548
		return -ENOSPC;
	}
	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
	EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;

	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
	return 0;       /* success */
}

1549
static void ext4_da_release_space(struct inode *inode, int to_free)
1550 1551 1552 1553
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	int total, mdb, mdb_free, release;

1554 1555 1556
	if (!to_free)
		return;		/* Nothing to release, exit */

1557
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572

	if (!EXT4_I(inode)->i_reserved_data_blocks) {
		/*
		 * if there is no reserved blocks, but we try to free some
		 * then the counter is messed up somewhere.
		 * but since this function is called from invalidate
		 * page, it's harmless to return without any action
		 */
		printk(KERN_INFO "ext4 delalloc try to release %d reserved "
			    "blocks for inode %lu, but there is no reserved "
			    "data blocks\n", to_free, inode->i_ino);
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
		return;
	}

1573
	/* recalculate the number of metablocks still need to be reserved */
1574
	total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1575 1576 1577 1578 1579 1580 1581 1582
	mdb = ext4_calc_metadata_amount(inode, total);

	/* figure out how many metablocks to release */
	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;

	release = to_free + mdb_free;

1583 1584
	/* update fs dirty blocks counter for truncate case */
	percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1585 1586

	/* update per-inode reservations */
1587 1588
	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
	EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612

	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}

static void ext4_da_page_release_reservation(struct page *page,
						unsigned long offset)
{
	int to_release = 0;
	struct buffer_head *head, *bh;
	unsigned int curr_off = 0;

	head = page_buffers(page);
	bh = head;
	do {
		unsigned int next_off = curr_off + bh->b_size;

		if ((offset <= curr_off) && (buffer_delay(bh))) {
			to_release++;
			clear_buffer_delay(bh);
		}
		curr_off = next_off;
	} while ((bh = bh->b_this_page) != head);
1613
	ext4_da_release_space(page->mapping->host, to_release);
1614
}
1615

1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
/*
 * Delayed allocation stuff
 */

struct mpage_da_data {
	struct inode *inode;
	struct buffer_head lbh;			/* extent of blocks */
	unsigned long first_page, next_page;	/* extent of pages */
	get_block_t *get_block;
	struct writeback_control *wbc;
1626 1627
	int io_done;
	long pages_written;
1628
	int retval;
1629 1630 1631 1632
};

/*
 * mpage_da_submit_io - walks through extent of pages and try to write
1633
 * them with writepage() call back
1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650
 *
 * @mpd->inode: inode
 * @mpd->first_page: first page of the extent
 * @mpd->next_page: page after the last page of the extent
 * @mpd->get_block: the filesystem's block mapper function
 *
 * By the time mpage_da_submit_io() is called we expect all blocks
 * to be allocated. this may be wrong if allocation failed.
 *
 * As pages are already locked by write_cache_pages(), we can't use it
 */
static int mpage_da_submit_io(struct mpage_da_data *mpd)
{
	struct address_space *mapping = mpd->inode->i_mapping;
	int ret = 0, err, nr_pages, i;
	unsigned long index, end;
	struct pagevec pvec;
1651
	long pages_skipped;
1652 1653 1654 1655 1656 1657 1658

	BUG_ON(mpd->next_page <= mpd->first_page);
	pagevec_init(&pvec, 0);
	index = mpd->first_page;
	end = mpd->next_page - 1;

	while (index <= end) {
1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670
		/*
		 * We can use PAGECACHE_TAG_DIRTY lookup here because
		 * even though we have cleared the dirty flag on the page
		 * We still keep the page in the radix tree with tag
		 * PAGECACHE_TAG_DIRTY. See clear_page_dirty_for_io.
		 * The PAGECACHE_TAG_DIRTY is cleared in set_page_writeback
		 * which is called via the below writepage callback.
		 */
		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
					PAGECACHE_TAG_DIRTY,
					min(end - index,
					(pgoff_t)PAGEVEC_SIZE-1) + 1);
1671 1672 1673 1674 1675
		if (nr_pages == 0)
			break;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

1676
			pages_skipped = mpd->wbc->pages_skipped;
1677
			err = mapping->a_ops->writepage(page, mpd->wbc);
1678 1679 1680 1681 1682
			if (!err && (pages_skipped == mpd->wbc->pages_skipped))
				/*
				 * have successfully written the page
				 * without skipping the same
				 */
1683
				mpd->pages_written++;
1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715
			/*
			 * In error case, we have to continue because
			 * remaining pages are still locked
			 * XXX: unlock and re-dirty them?
			 */
			if (ret == 0)
				ret = err;
		}
		pagevec_release(&pvec);
	}
	return ret;
}

/*
 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
 *
 * @mpd->inode - inode to walk through
 * @exbh->b_blocknr - first block on a disk
 * @exbh->b_size - amount of space in bytes
 * @logical - first logical block to start assignment with
 *
 * the function goes through all passed space and put actual disk
 * block numbers into buffer heads, dropping BH_Delay
 */
static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
				 struct buffer_head *exbh)
{
	struct inode *inode = mpd->inode;
	struct address_space *mapping = inode->i_mapping;
	int blocks = exbh->b_size >> inode->i_blkbits;
	sector_t pblock = exbh->b_blocknr, cur_logical;
	struct buffer_head *head, *bh;
1716
	pgoff_t index, end;
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758
	struct pagevec pvec;
	int nr_pages, i;

	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
	end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
	cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);

	pagevec_init(&pvec, 0);

	while (index <= end) {
		/* XXX: optimize tail */
		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
		if (nr_pages == 0)
			break;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

			index = page->index;
			if (index > end)
				break;
			index++;

			BUG_ON(!PageLocked(page));
			BUG_ON(PageWriteback(page));
			BUG_ON(!page_has_buffers(page));

			bh = page_buffers(page);
			head = bh;

			/* skip blocks out of the range */
			do {
				if (cur_logical >= logical)
					break;
				cur_logical++;
			} while ((bh = bh->b_this_page) != head);

			do {
				if (cur_logical >= logical + blocks)
					break;
				if (buffer_delay(bh)) {
					bh->b_blocknr = pblock;
					clear_buffer_delay(bh);
1759 1760 1761 1762 1763 1764 1765
					bh->b_bdev = inode->i_sb->s_bdev;
				} else if (buffer_unwritten(bh)) {
					bh->b_blocknr = pblock;
					clear_buffer_unwritten(bh);
					set_buffer_mapped(bh);
					set_buffer_new(bh);
					bh->b_bdev = inode->i_sb->s_bdev;
1766
				} else if (buffer_mapped(bh))
1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792
					BUG_ON(bh->b_blocknr != pblock);

				cur_logical++;
				pblock++;
			} while ((bh = bh->b_this_page) != head);
		}
		pagevec_release(&pvec);
	}
}


/*
 * __unmap_underlying_blocks - just a helper function to unmap
 * set of blocks described by @bh
 */
static inline void __unmap_underlying_blocks(struct inode *inode,
					     struct buffer_head *bh)
{
	struct block_device *bdev = inode->i_sb->s_bdev;
	int blocks, i;

	blocks = bh->b_size >> inode->i_blkbits;
	for (i = 0; i < blocks; i++)
		unmap_underlying_metadata(bdev, bh->b_blocknr + i);
}

1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825
static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
					sector_t logical, long blk_cnt)
{
	int nr_pages, i;
	pgoff_t index, end;
	struct pagevec pvec;
	struct inode *inode = mpd->inode;
	struct address_space *mapping = inode->i_mapping;

	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
	end   = (logical + blk_cnt - 1) >>
				(PAGE_CACHE_SHIFT - inode->i_blkbits);
	while (index <= end) {
		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
		if (nr_pages == 0)
			break;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];
			index = page->index;
			if (index > end)
				break;
			index++;

			BUG_ON(!PageLocked(page));
			BUG_ON(PageWriteback(page));
			block_invalidatepage(page, 0);
			ClearPageUptodate(page);
			unlock_page(page);
		}
	}
	return;
}

1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843
static void ext4_print_free_blocks(struct inode *inode)
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	printk(KERN_EMERG "Total free blocks count %lld\n",
			ext4_count_free_blocks(inode->i_sb));
	printk(KERN_EMERG "Free/Dirty block details\n");
	printk(KERN_EMERG "free_blocks=%lld\n",
			percpu_counter_sum(&sbi->s_freeblocks_counter));
	printk(KERN_EMERG "dirty_blocks=%lld\n",
			percpu_counter_sum(&sbi->s_dirtyblocks_counter));
	printk(KERN_EMERG "Block reservation details\n");
	printk(KERN_EMERG "i_reserved_data_blocks=%lu\n",
			EXT4_I(inode)->i_reserved_data_blocks);
	printk(KERN_EMERG "i_reserved_meta_blocks=%lu\n",
			EXT4_I(inode)->i_reserved_meta_blocks);
	return;
}

1844 1845 1846 1847 1848 1849 1850 1851 1852
/*
 * mpage_da_map_blocks - go through given space
 *
 * @mpd->lbh - bh describing space
 * @mpd->get_block - the filesystem's block mapper function
 *
 * The function skips space we know is already mapped to disk blocks.
 *
 */
1853
static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
1854
{
1855
	int err = 0;
A
Aneesh Kumar K.V 已提交
1856
	struct buffer_head new;
1857
	struct buffer_head *lbh = &mpd->lbh;
1858
	sector_t next;
1859 1860 1861 1862 1863

	/*
	 * We consider only non-mapped and non-allocated blocks
	 */
	if (buffer_mapped(lbh) && !buffer_delay(lbh))
1864
		return 0;
1865 1866 1867
	new.b_state = lbh->b_state;
	new.b_blocknr = 0;
	new.b_size = lbh->b_size;
1868
	next = lbh->b_blocknr;
1869 1870 1871 1872 1873
	/*
	 * If we didn't accumulate anything
	 * to write simply return
	 */
	if (!new.b_size)
1874
		return 0;
1875
	err = mpd->get_block(mpd->inode, next, &new, 1);
1876 1877 1878 1879 1880 1881 1882 1883 1884
	if (err) {

		/* If get block returns with error
		 * we simply return. Later writepage
		 * will redirty the page and writepages
		 * will find the dirty page again
		 */
		if (err == -EAGAIN)
			return 0;
1885 1886 1887 1888 1889 1890 1891

		if (err == -ENOSPC &&
				ext4_count_free_blocks(mpd->inode->i_sb)) {
			mpd->retval = err;
			return 0;
		}

1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907
		/*
		 * get block failure will cause us
		 * to loop in writepages. Because
		 * a_ops->writepage won't be able to
		 * make progress. The page will be redirtied
		 * by writepage and writepages will again
		 * try to write the same.
		 */
		printk(KERN_EMERG "%s block allocation failed for inode %lu "
				  "at logical offset %llu with max blocks "
				  "%zd with error %d\n",
				  __func__, mpd->inode->i_ino,
				  (unsigned long long)next,
				  lbh->b_size >> mpd->inode->i_blkbits, err);
		printk(KERN_EMERG "This should not happen.!! "
					"Data will be lost\n");
A
Aneesh Kumar K.V 已提交
1908
		if (err == -ENOSPC) {
1909
			ext4_print_free_blocks(mpd->inode);
A
Aneesh Kumar K.V 已提交
1910
		}
1911 1912 1913 1914 1915
		/* invlaidate all the pages */
		ext4_da_block_invalidatepages(mpd, next,
				lbh->b_size >> mpd->inode->i_blkbits);
		return err;
	}
1916
	BUG_ON(new.b_size == 0);
1917

1918 1919
	if (buffer_new(&new))
		__unmap_underlying_blocks(mpd->inode, &new);
1920

1921 1922 1923 1924 1925 1926
	/*
	 * If blocks are delayed marked, we need to
	 * put actual blocknr and drop delayed bit
	 */
	if (buffer_delay(lbh) || buffer_unwritten(lbh))
		mpage_put_bnr_to_bhs(mpd, next, &new);
1927

1928
	return 0;
1929 1930
}

1931 1932
#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
		(1 << BH_Delay) | (1 << BH_Unwritten))
1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946

/*
 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
 *
 * @mpd->lbh - extent of blocks
 * @logical - logical number of the block in the file
 * @bh - bh of the block (used to access block's state)
 *
 * the function is used to collect contig. blocks in same state
 */
static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
				   sector_t logical, struct buffer_head *bh)
{
	sector_t next;
1947 1948 1949
	size_t b_size = bh->b_size;
	struct buffer_head *lbh = &mpd->lbh;
	int nrblocks = lbh->b_size >> mpd->inode->i_blkbits;
1950

1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972
	/* check if thereserved journal credits might overflow */
	if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
		if (nrblocks >= EXT4_MAX_TRANS_DATA) {
			/*
			 * With non-extent format we are limited by the journal
			 * credit available.  Total credit needed to insert
			 * nrblocks contiguous blocks is dependent on the
			 * nrblocks.  So limit nrblocks.
			 */
			goto flush_it;
		} else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
				EXT4_MAX_TRANS_DATA) {
			/*
			 * Adding the new buffer_head would make it cross the
			 * allowed limit for which we have journal credit
			 * reserved. So limit the new bh->b_size
			 */
			b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
						mpd->inode->i_blkbits;
			/* we will do mpage_da_submit_io in the next loop */
		}
	}
1973 1974 1975 1976 1977
	/*
	 * First block in the extent
	 */
	if (lbh->b_size == 0) {
		lbh->b_blocknr = logical;
1978
		lbh->b_size = b_size;
1979 1980 1981 1982
		lbh->b_state = bh->b_state & BH_FLAGS;
		return;
	}

1983
	next = lbh->b_blocknr + nrblocks;
1984 1985 1986 1987
	/*
	 * Can we merge the block to our big extent?
	 */
	if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) {
1988
		lbh->b_size += b_size;
1989 1990 1991
		return;
	}

1992
flush_it:
1993 1994 1995 1996
	/*
	 * We couldn't merge the block to our extent, so we
	 * need to flush current  extent and start new one
	 */
1997 1998
	if (mpage_da_map_blocks(mpd) == 0)
		mpage_da_submit_io(mpd);
1999 2000
	mpd->io_done = 1;
	return;
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
}

/*
 * __mpage_da_writepage - finds extent of pages and blocks
 *
 * @page: page to consider
 * @wbc: not used, we just follow rules
 * @data: context
 *
 * The function finds extents of pages and scan them for all blocks.
 */
static int __mpage_da_writepage(struct page *page,
				struct writeback_control *wbc, void *data)
{
	struct mpage_da_data *mpd = data;
	struct inode *inode = mpd->inode;
	struct buffer_head *bh, *head, fake;
	sector_t logical;

2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030
	if (mpd->io_done) {
		/*
		 * Rest of the page in the page_vec
		 * redirty then and skip then. We will
		 * try to to write them again after
		 * starting a new transaction
		 */
		redirty_page_for_writepage(wbc, page);
		unlock_page(page);
		return MPAGE_DA_EXTENT_TAIL;
	}
2031 2032 2033 2034 2035 2036
	/*
	 * Can we merge this page to current extent?
	 */
	if (mpd->next_page != page->index) {
		/*
		 * Nope, we can't. So, we map non-allocated blocks
2037
		 * and start IO on them using writepage()
2038 2039
		 */
		if (mpd->next_page != mpd->first_page) {
2040 2041
			if (mpage_da_map_blocks(mpd) == 0)
				mpage_da_submit_io(mpd);
2042 2043 2044 2045 2046 2047 2048
			/*
			 * skip rest of the page in the page_vec
			 */
			mpd->io_done = 1;
			redirty_page_for_writepage(wbc, page);
			unlock_page(page);
			return MPAGE_DA_EXTENT_TAIL;
2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078
		}

		/*
		 * Start next extent of pages ...
		 */
		mpd->first_page = page->index;

		/*
		 * ... and blocks
		 */
		mpd->lbh.b_size = 0;
		mpd->lbh.b_state = 0;
		mpd->lbh.b_blocknr = 0;
	}

	mpd->next_page = page->index + 1;
	logical = (sector_t) page->index <<
		  (PAGE_CACHE_SHIFT - inode->i_blkbits);

	if (!page_has_buffers(page)) {
		/*
		 * There is no attached buffer heads yet (mmap?)
		 * we treat the page asfull of dirty blocks
		 */
		bh = &fake;
		bh->b_size = PAGE_CACHE_SIZE;
		bh->b_state = 0;
		set_buffer_dirty(bh);
		set_buffer_uptodate(bh);
		mpage_add_bh_to_extent(mpd, logical, bh);
2079 2080
		if (mpd->io_done)
			return MPAGE_DA_EXTENT_TAIL;
2081 2082 2083 2084 2085 2086 2087 2088
	} else {
		/*
		 * Page with regular buffer heads, just add all dirty ones
		 */
		head = page_buffers(page);
		bh = head;
		do {
			BUG_ON(buffer_locked(bh));
2089 2090
			if (buffer_dirty(bh) &&
				(!buffer_mapped(bh) || buffer_delay(bh))) {
2091
				mpage_add_bh_to_extent(mpd, logical, bh);
2092 2093 2094
				if (mpd->io_done)
					return MPAGE_DA_EXTENT_TAIL;
			}
2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115
			logical++;
		} while ((bh = bh->b_this_page) != head);
	}

	return 0;
}

/*
 * mpage_da_writepages - walk the list of dirty pages of the given
 * address space, allocates non-allocated blocks, maps newly-allocated
 * blocks to existing bhs and issue IO them
 *
 * @mapping: address space structure to write
 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
 * @get_block: the filesystem's block mapper function.
 *
 * This is a library function, which implements the writepages()
 * address_space_operation.
 */
static int mpage_da_writepages(struct address_space *mapping,
			       struct writeback_control *wbc,
2116
			       struct mpage_da_data *mpd)
2117 2118 2119
{
	int ret;

2120
	if (!mpd->get_block)
2121 2122
		return generic_writepages(mapping, wbc);

2123 2124 2125 2126 2127 2128 2129 2130
	mpd->lbh.b_size = 0;
	mpd->lbh.b_state = 0;
	mpd->lbh.b_blocknr = 0;
	mpd->first_page = 0;
	mpd->next_page = 0;
	mpd->io_done = 0;
	mpd->pages_written = 0;
	mpd->retval = 0;
2131

2132
	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
2133 2134 2135
	/*
	 * Handle last extent of pages
	 */
2136 2137 2138
	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
		if (mpage_da_map_blocks(mpd) == 0)
			mpage_da_submit_io(mpd);
2139

2140 2141 2142 2143
		mpd->io_done = 1;
		ret = MPAGE_DA_EXTENT_TAIL;
	}
	wbc->nr_to_write -= mpd->pages_written;
2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163
	return ret;
}

/*
 * this is a special callback for ->write_begin() only
 * it's intention is to return mapped block or reserve space
 */
static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
				  struct buffer_head *bh_result, int create)
{
	int ret = 0;

	BUG_ON(create == 0);
	BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);

	/*
	 * first, we need to know whether the block is allocated already
	 * preallocated blocks are unmapped but should treated
	 * the same as allocated blocks.
	 */
2164 2165 2166
	ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1,  bh_result, 0, 0, 0);
	if ((ret == 0) && !buffer_delay(bh_result)) {
		/* the block isn't (pre)allocated yet, let's reserve space */
2167 2168 2169 2170
		/*
		 * XXX: __block_prepare_write() unmaps passed block,
		 * is it OK?
		 */
2171 2172 2173 2174 2175
		ret = ext4_da_reserve_space(inode, 1);
		if (ret)
			/* not enough space to reserve */
			return ret;

2176 2177 2178 2179 2180 2181 2182 2183 2184 2185
		map_bh(bh_result, inode->i_sb, 0);
		set_buffer_new(bh_result);
		set_buffer_delay(bh_result);
	} else if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
	}

	return ret;
}
2186
#define		EXT4_DELALLOC_RSVED	1
2187 2188 2189
static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
				   struct buffer_head *bh_result, int create)
{
2190
	int ret;
2191 2192 2193 2194
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
	loff_t disksize = EXT4_I(inode)->i_disksize;
	handle_t *handle = NULL;

2195
	handle = ext4_journal_current_handle();
2196 2197 2198
	BUG_ON(!handle);
	ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
			bh_result, create, 0, EXT4_DELALLOC_RSVED);
2199
	if (ret > 0) {
2200

2201 2202
		bh_result->b_size = (ret << inode->i_blkbits);

2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213
		if (ext4_should_order_data(inode)) {
			int retval;
			retval = ext4_jbd2_file_inode(handle, inode);
			if (retval)
				/*
				 * Failed to add inode for ordered
				 * mode. Don't update file size
				 */
				return retval;
		}

2214 2215 2216 2217 2218 2219 2220 2221 2222
		/*
		 * Update on-disk size along with block allocation
		 * we don't use 'extend_disksize' as size may change
		 * within already allocated block -bzzz
		 */
		disksize = ((loff_t) iblock + ret) << inode->i_blkbits;
		if (disksize > i_size_read(inode))
			disksize = i_size_read(inode);
		if (disksize > EXT4_I(inode)->i_disksize) {
2223 2224 2225
			ext4_update_i_disksize(inode, disksize);
			ret = ext4_mark_inode_dirty(handle, inode);
			return ret;
2226 2227 2228 2229 2230
		}
		ret = 0;
	}
	return ret;
}
2231 2232 2233

static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
{
2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257
	/*
	 * unmapped buffer is possible for holes.
	 * delay buffer is possible with delayed allocation
	 */
	return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh));
}

static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
				   struct buffer_head *bh_result, int create)
{
	int ret = 0;
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

	/*
	 * we don't want to do block allocation in writepage
	 * so call get_block_wrap with create = 0
	 */
	ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks,
				   bh_result, 0, 0, 0);
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
	}
	return ret;
2258 2259 2260
}

/*
2261 2262 2263 2264
 * get called vi ext4_da_writepages after taking page lock (have journal handle)
 * get called via journal_submit_inode_data_buffers (no journal handle)
 * get called via shrink_page_list via pdflush (no journal handle)
 * or grab_page_cache when doing write_begin (have journal handle)
2265
 */
2266 2267 2268 2269
static int ext4_da_writepage(struct page *page,
				struct writeback_control *wbc)
{
	int ret = 0;
2270 2271 2272 2273 2274
	loff_t size;
	unsigned long len;
	struct buffer_head *page_bufs;
	struct inode *inode = page->mapping->host;

2275 2276 2277 2278 2279
	size = i_size_read(inode);
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
2280

2281
	if (page_has_buffers(page)) {
2282
		page_bufs = page_buffers(page);
2283 2284
		if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
					ext4_bh_unmapped_or_delay)) {
2285
			/*
2286 2287
			 * We don't want to do  block allocation
			 * So redirty the page and return
2288 2289 2290
			 * We may reach here when we do a journal commit
			 * via journal_submit_inode_data_buffers.
			 * If we don't have mapping block we just ignore
2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326
			 * them. We can also reach here via shrink_page_list
			 */
			redirty_page_for_writepage(wbc, page);
			unlock_page(page);
			return 0;
		}
	} else {
		/*
		 * The test for page_has_buffers() is subtle:
		 * We know the page is dirty but it lost buffers. That means
		 * that at some moment in time after write_begin()/write_end()
		 * has been called all buffers have been clean and thus they
		 * must have been written at least once. So they are all
		 * mapped and we can happily proceed with mapping them
		 * and writing the page.
		 *
		 * Try to initialize the buffer_heads and check whether
		 * all are mapped and non delay. We don't want to
		 * do block allocation here.
		 */
		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
						ext4_normal_get_block_write);
		if (!ret) {
			page_bufs = page_buffers(page);
			/* check whether all are mapped and non delay */
			if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
						ext4_bh_unmapped_or_delay)) {
				redirty_page_for_writepage(wbc, page);
				unlock_page(page);
				return 0;
			}
		} else {
			/*
			 * We can't do block allocation here
			 * so just redity the page and unlock
			 * and return
2327 2328 2329 2330 2331
			 */
			redirty_page_for_writepage(wbc, page);
			unlock_page(page);
			return 0;
		}
2332 2333
		/* now mark the buffer_heads as dirty and uptodate */
		block_commit_write(page, 0, PAGE_CACHE_SIZE);
2334 2335 2336
	}

	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2337
		ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
2338
	else
2339 2340 2341
		ret = block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
2342 2343 2344 2345

	return ret;
}

2346
/*
2347 2348 2349 2350 2351
 * This is called via ext4_da_writepages() to
 * calulate the total number of credits to reserve to fit
 * a single extent allocation into a single transaction,
 * ext4_da_writpeages() will loop calling this before
 * the block allocation.
2352
 */
2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369

static int ext4_da_writepages_trans_blocks(struct inode *inode)
{
	int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;

	/*
	 * With non-extent format the journal credit needed to
	 * insert nrblocks contiguous block is dependent on
	 * number of contiguous block. So we will limit
	 * number of contiguous block to a sane value
	 */
	if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
	    (max_blocks > EXT4_MAX_TRANS_DATA))
		max_blocks = EXT4_MAX_TRANS_DATA;

	return ext4_chunk_trans_blocks(inode, max_blocks);
}
2370

2371
static int ext4_da_writepages(struct address_space *mapping,
2372
			      struct writeback_control *wbc)
2373
{
2374 2375
	pgoff_t	index;
	int range_whole = 0;
2376
	handle_t *handle = NULL;
2377
	struct mpage_da_data mpd;
2378
	struct inode *inode = mapping->host;
2379 2380
	int no_nrwrite_index_update;
	long pages_written = 0, pages_skipped;
2381 2382
	int needed_blocks, ret = 0, nr_to_writebump = 0;
	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2383 2384 2385 2386 2387 2388

	/*
	 * No pages to write? This is mainly a kludge to avoid starting
	 * a transaction for special inodes like journal inode on last iput()
	 * because that could violate lock ordering on umount
	 */
2389
	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2390
		return 0;
2391 2392 2393 2394 2395 2396 2397 2398 2399 2400
	/*
	 * Make sure nr_to_write is >= sbi->s_mb_stream_request
	 * This make sure small files blocks are allocated in
	 * single attempt. This ensure that small files
	 * get less fragmented.
	 */
	if (wbc->nr_to_write < sbi->s_mb_stream_request) {
		nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
		wbc->nr_to_write = sbi->s_mb_stream_request;
	}
2401 2402
	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
		range_whole = 1;
2403

2404 2405 2406 2407
	if (wbc->range_cyclic)
		index = mapping->writeback_index;
	else
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
2408

2409 2410 2411
	mpd.wbc = wbc;
	mpd.inode = mapping->host;

2412 2413 2414 2415 2416 2417 2418 2419 2420
	/*
	 * we don't want write_cache_pages to update
	 * nr_to_write and writeback_index
	 */
	no_nrwrite_index_update = wbc->no_nrwrite_index_update;
	wbc->no_nrwrite_index_update = 1;
	pages_skipped = wbc->pages_skipped;

	while (!ret && wbc->nr_to_write > 0) {
2421 2422 2423 2424 2425 2426 2427 2428

		/*
		 * we  insert one extent at a time. So we need
		 * credit needed for single extent allocation.
		 * journalled mode is currently not supported
		 * by delalloc
		 */
		BUG_ON(ext4_should_journal_data(inode));
2429
		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2430

2431 2432 2433 2434
		/* start a new transaction*/
		handle = ext4_journal_start(inode, needed_blocks);
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
2435 2436 2437 2438
			printk(KERN_EMERG "%s: jbd2_start: "
			       "%ld pages, ino %lu; err %d\n", __func__,
				wbc->nr_to_write, inode->i_ino, ret);
			dump_stack();
2439 2440
			goto out_writepages;
		}
2441 2442 2443
		mpd.get_block = ext4_da_get_block_write;
		ret = mpage_da_writepages(mapping, wbc, &mpd);

2444
		ext4_journal_stop(handle);
2445

2446 2447 2448 2449 2450
		if (mpd.retval == -ENOSPC) {
			/* commit the transaction which would
			 * free blocks released in the transaction
			 * and try again
			 */
2451
			jbd2_journal_force_commit_nested(sbi->s_journal);
2452 2453 2454
			wbc->pages_skipped = pages_skipped;
			ret = 0;
		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
2455 2456 2457 2458
			/*
			 * got one extent now try with
			 * rest of the pages
			 */
2459 2460
			pages_written += mpd.pages_written;
			wbc->pages_skipped = pages_skipped;
2461
			ret = 0;
2462
		} else if (wbc->nr_to_write)
2463 2464 2465 2466 2467 2468
			/*
			 * There is no more writeout needed
			 * or we requested for a noblocking writeout
			 * and we found the device congested
			 */
			break;
2469
	}
2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482
	if (pages_skipped != wbc->pages_skipped)
		printk(KERN_EMERG "This should not happen leaving %s "
				"with nr_to_write = %ld ret = %d\n",
				__func__, wbc->nr_to_write, ret);

	/* Update index */
	index += pages_written;
	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
		/*
		 * set the writeback_index so that range_cyclic
		 * mode will write it back later
		 */
		mapping->writeback_index = index;
2483

2484
out_writepages:
2485 2486 2487
	if (!no_nrwrite_index_update)
		wbc->no_nrwrite_index_update = 0;
	wbc->nr_to_write -= nr_to_writebump;
2488
	return ret;
2489 2490
}

2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517
#define FALL_BACK_TO_NONDELALLOC 1
static int ext4_nonda_switch(struct super_block *sb)
{
	s64 free_blocks, dirty_blocks;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	/*
	 * switch to non delalloc mode if we are running low
	 * on free block. The free block accounting via percpu
	 * counters can get slightly wrong with FBC_BATCH getting
	 * accumulated on each CPU without updating global counters
	 * Delalloc need an accurate free block accounting. So switch
	 * to non delalloc when we are near to error range.
	 */
	free_blocks  = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
	dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
	if (2 * free_blocks < 3 * dirty_blocks ||
		free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
		/*
		 * free block count is less that 150% of dirty blocks
		 * or free blocks is less that watermark
		 */
		return 1;
	}
	return 0;
}

2518 2519 2520 2521
static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
{
2522
	int ret, retries = 0;
2523 2524 2525 2526 2527 2528 2529 2530 2531
	struct page *page;
	pgoff_t index;
	unsigned from, to;
	struct inode *inode = mapping->host;
	handle_t *handle;

	index = pos >> PAGE_CACHE_SHIFT;
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;
2532 2533 2534 2535 2536 2537 2538

	if (ext4_nonda_switch(inode->i_sb)) {
		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
		return ext4_write_begin(file, mapping, pos,
					len, flags, pagep, fsdata);
	}
	*fsdata = (void *)0;
2539
retry:
2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552
	/*
	 * With delayed allocation, we don't log the i_disksize update
	 * if there is delayed block allocation. But we still need
	 * to journalling the i_disksize update if writes to the end
	 * of file which has an already mapped buffer.
	 */
	handle = ext4_journal_start(inode, 1);
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out;
	}

	page = __grab_cache_page(mapping, index);
2553 2554 2555 2556 2557
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
2558 2559 2560 2561 2562 2563 2564 2565
	*pagep = page;

	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
							ext4_da_get_block_prep);
	if (ret < 0) {
		unlock_page(page);
		ext4_journal_stop(handle);
		page_cache_release(page);
2566 2567 2568 2569 2570 2571 2572
		/*
		 * block_write_begin may have instantiated a few blocks
		 * outside i_size.  Trim these off again. Don't need
		 * i_size_read because we hold i_mutex.
		 */
		if (pos + len > inode->i_size)
			vmtruncate(inode, inode->i_size);
2573 2574
	}

2575 2576
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
2577 2578 2579 2580
out:
	return ret;
}

2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595
/*
 * Check if we should update i_disksize
 * when write to the end of file but not require block allocation
 */
static int ext4_da_should_update_i_disksize(struct page *page,
					 unsigned long offset)
{
	struct buffer_head *bh;
	struct inode *inode = page->mapping->host;
	unsigned int idx;
	int i;

	bh = page_buffers(page);
	idx = offset >> inode->i_blkbits;

2596
	for (i = 0; i < idx; i++)
2597 2598 2599 2600 2601 2602 2603
		bh = bh->b_this_page;

	if (!buffer_mapped(bh) || (buffer_delay(bh)))
		return 0;
	return 1;
}

2604 2605 2606 2607 2608 2609 2610 2611 2612
static int ext4_da_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
{
	struct inode *inode = mapping->host;
	int ret = 0, ret2;
	handle_t *handle = ext4_journal_current_handle();
	loff_t new_i_size;
2613
	unsigned long start, end;
2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626
	int write_mode = (int)(unsigned long)fsdata;

	if (write_mode == FALL_BACK_TO_NONDELALLOC) {
		if (ext4_should_order_data(inode)) {
			return ext4_ordered_write_end(file, mapping, pos,
					len, copied, page, fsdata);
		} else if (ext4_should_writeback_data(inode)) {
			return ext4_writeback_write_end(file, mapping, pos,
					len, copied, page, fsdata);
		} else {
			BUG();
		}
	}
2627 2628

	start = pos & (PAGE_CACHE_SIZE - 1);
2629
	end = start + copied - 1;
2630 2631 2632 2633 2634 2635 2636 2637

	/*
	 * generic_write_end() will run mark_inode_dirty() if i_size
	 * changes.  So let's piggyback the i_disksize mark_inode_dirty
	 * into that.
	 */

	new_i_size = pos + copied;
2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648
	if (new_i_size > EXT4_I(inode)->i_disksize) {
		if (ext4_da_should_update_i_disksize(page, end)) {
			down_write(&EXT4_I(inode)->i_data_sem);
			if (new_i_size > EXT4_I(inode)->i_disksize) {
				/*
				 * Updating i_disksize when extending file
				 * without needing block allocation
				 */
				if (ext4_should_order_data(inode))
					ret = ext4_jbd2_file_inode(handle,
								   inode);
2649

2650 2651 2652
				EXT4_I(inode)->i_disksize = new_i_size;
			}
			up_write(&EXT4_I(inode)->i_data_sem);
2653 2654 2655 2656 2657
			/* We need to mark inode dirty even if
			 * new_i_size is less that inode->i_size
			 * bu greater than i_disksize.(hint delalloc)
			 */
			ext4_mark_inode_dirty(handle, inode);
2658
		}
2659
	}
2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680
	ret2 = generic_write_end(file, mapping, pos, len, copied,
							page, fsdata);
	copied = ret2;
	if (ret2 < 0)
		ret = ret2;
	ret2 = ext4_journal_stop(handle);
	if (!ret)
		ret = ret2;

	return ret ? ret : copied;
}

static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
{
	/*
	 * Drop reserved blocks
	 */
	BUG_ON(!PageLocked(page));
	if (!page_has_buffers(page))
		goto out;

2681
	ext4_da_page_release_reservation(page, offset);
2682 2683 2684 2685 2686 2687 2688 2689

out:
	ext4_invalidatepage(page, offset);

	return;
}


2690 2691 2692 2693 2694
/*
 * 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
2695
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
2696 2697 2698 2699 2700 2701 2702 2703
 * 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.
 */
2704
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2705 2706 2707 2708 2709
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

2710 2711 2712 2713 2714 2715 2716 2717 2718 2719
	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
			test_opt(inode->i_sb, DELALLOC)) {
		/*
		 * With delalloc we want to sync the file
		 * so that we can make sure we allocate
		 * blocks for file
		 */
		filemap_write_and_wait(mapping);
	}

2720
	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731
		/*
		 * 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.)
		 *
2732
		 * NB. EXT4_STATE_JDATA is not set on files other than
2733 2734 2735 2736 2737 2738
		 * 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.
		 */

2739 2740
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
2741 2742 2743
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
2744 2745 2746 2747 2748

		if (err)
			return 0;
	}

2749
	return generic_block_bmap(mapping, block, ext4_get_block);
2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764
}

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;
}

/*
2765 2766 2767 2768 2769 2770 2771 2772
 * Note that we don't need to start a transaction unless we're journaling data
 * because we should have holes filled from ext4_page_mkwrite(). We even don't
 * need to file the inode to the transaction's list in ordered mode because if
 * we are writing back data added by write(), the inode is already there and if
 * we are writing back data modified via mmap(), noone guarantees in which
 * transaction the data will hit the disk. In case we are journaling data, we
 * cannot start transaction directly because transaction start ranks above page
 * lock so we have to do some magic.
2773
 *
2774
 * In all journaling modes block_write_full_page() will start the I/O.
2775 2776 2777
 *
 * Problem:
 *
2778 2779
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
2780 2781 2782
 *
 * Similar for:
 *
2783
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
2784
 *
2785
 * Same applies to ext4_get_block().  We will deadlock on various things like
2786
 * lock_journal and i_data_sem
2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816
 *
 * 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.
 *
 */
2817
static int __ext4_normal_writepage(struct page *page,
2818 2819 2820 2821 2822
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;

	if (test_opt(inode->i_sb, NOBH))
2823 2824
		return nobh_writepage(page,
					ext4_normal_get_block_write, wbc);
2825
	else
2826 2827 2828
		return block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
2829 2830
}

2831
static int ext4_normal_writepage(struct page *page,
2832 2833 2834
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
2835 2836 2837 2838 2839 2840 2841 2842
	loff_t size = i_size_read(inode);
	loff_t len;

	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856

	if (page_has_buffers(page)) {
		/* if page has buffers it should all be mapped
		 * and allocated. If there are not buffers attached
		 * to the page we know the page is dirty but it lost
		 * buffers. That means that at some moment in time
		 * after write_begin() / write_end() has been called
		 * all buffers have been clean and thus they must have been
		 * written at least once. So they are all mapped and we can
		 * happily proceed with mapping them and writing the page.
		 */
		BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
					ext4_bh_unmapped_or_delay));
	}
2857 2858

	if (!ext4_journal_current_handle())
2859
		return __ext4_normal_writepage(page, wbc);
2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871

	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
	return 0;
}

static int __ext4_journalled_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode = mapping->host;
	struct buffer_head *page_bufs;
2872 2873 2874 2875
	handle_t *handle = NULL;
	int ret = 0;
	int err;

2876 2877
	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
					ext4_normal_get_block_write);
2878 2879 2880 2881 2882 2883 2884 2885 2886
	if (ret != 0)
		goto out_unlock;

	page_bufs = page_buffers(page);
	walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
								bget_one);
	/* As soon as we unlock the page, it can go away, but we have
	 * references to buffers so we are safe */
	unlock_page(page);
2887

2888
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2889 2890
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
2891
		goto out;
2892 2893
	}

2894 2895
	ret = walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
2896

2897 2898 2899 2900
	err = walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, write_end_fn);
	if (ret == 0)
		ret = err;
2901
	err = ext4_journal_stop(handle);
2902 2903 2904
	if (!ret)
		ret = err;

2905 2906 2907 2908 2909 2910
	walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, bput_one);
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
	goto out;

out_unlock:
2911
	unlock_page(page);
2912
out:
2913 2914 2915
	return ret;
}

2916
static int ext4_journalled_writepage(struct page *page,
2917 2918 2919
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
2920 2921
	loff_t size = i_size_read(inode);
	loff_t len;
2922

2923 2924 2925 2926 2927
	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941

	if (page_has_buffers(page)) {
		/* if page has buffers it should all be mapped
		 * and allocated. If there are not buffers attached
		 * to the page we know the page is dirty but it lost
		 * buffers. That means that at some moment in time
		 * after write_begin() / write_end() has been called
		 * all buffers have been clean and thus they must have been
		 * written at least once. So they are all mapped and we can
		 * happily proceed with mapping them and writing the page.
		 */
		BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
					ext4_bh_unmapped_or_delay));
	}
2942

2943
	if (ext4_journal_current_handle())
2944 2945
		goto no_write;

2946
	if (PageChecked(page)) {
2947 2948 2949 2950 2951
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
2952
		return __ext4_journalled_writepage(page, wbc);
2953 2954 2955 2956 2957 2958
	} 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.
		 */
2959 2960 2961
		return block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
2962 2963 2964 2965
	}
no_write:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
2966
	return 0;
2967 2968
}

2969
static int ext4_readpage(struct file *file, struct page *page)
2970
{
2971
	return mpage_readpage(page, ext4_get_block);
2972 2973 2974
}

static int
2975
ext4_readpages(struct file *file, struct address_space *mapping,
2976 2977
		struct list_head *pages, unsigned nr_pages)
{
2978
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2979 2980
}

2981
static void ext4_invalidatepage(struct page *page, unsigned long offset)
2982
{
2983
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2984 2985 2986 2987 2988 2989 2990

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

2991
	jbd2_journal_invalidatepage(journal, page, offset);
2992 2993
}

2994
static int ext4_releasepage(struct page *page, gfp_t wait)
2995
{
2996
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2997 2998 2999 3000

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
3001
	return jbd2_journal_try_to_free_buffers(journal, page, wait);
3002 3003 3004 3005 3006 3007 3008 3009
}

/*
 * 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
J
Jan Kara 已提交
3010 3011
 * crashes then stale disk data _may_ be exposed inside the file. But current
 * VFS code falls back into buffered path in that case so we are safe.
3012
 */
3013
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3014 3015 3016 3017 3018
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
3019
	struct ext4_inode_info *ei = EXT4_I(inode);
J
Jan Kara 已提交
3020
	handle_t *handle;
3021 3022 3023 3024 3025 3026 3027 3028
	ssize_t ret;
	int orphan = 0;
	size_t count = iov_length(iov, nr_segs);

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

		if (final_size > inode->i_size) {
J
Jan Kara 已提交
3029 3030 3031 3032 3033 3034
			/* Credits for sb + inode write */
			handle = ext4_journal_start(inode, 2);
			if (IS_ERR(handle)) {
				ret = PTR_ERR(handle);
				goto out;
			}
3035
			ret = ext4_orphan_add(handle, inode);
J
Jan Kara 已提交
3036 3037 3038 3039
			if (ret) {
				ext4_journal_stop(handle);
				goto out;
			}
3040 3041
			orphan = 1;
			ei->i_disksize = inode->i_size;
J
Jan Kara 已提交
3042
			ext4_journal_stop(handle);
3043 3044 3045 3046 3047
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
3048
				 ext4_get_block, NULL);
3049

J
Jan Kara 已提交
3050
	if (orphan) {
3051 3052
		int err;

J
Jan Kara 已提交
3053 3054 3055 3056 3057 3058 3059 3060 3061 3062
		/* Credits for sb + inode write */
		handle = ext4_journal_start(inode, 2);
		if (IS_ERR(handle)) {
			/* This is really bad luck. We've written the data
			 * but cannot extend i_size. Bail out and pretend
			 * the write failed... */
			ret = PTR_ERR(handle);
			goto out;
		}
		if (inode->i_nlink)
3063
			ext4_orphan_del(handle, inode);
J
Jan Kara 已提交
3064
		if (ret > 0) {
3065 3066 3067 3068 3069 3070 3071 3072
			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
3073
				 * ext4_mark_inode_dirty() to userspace.  So
3074 3075
				 * ignore it.
				 */
3076
				ext4_mark_inode_dirty(handle, inode);
3077 3078
			}
		}
3079
		err = ext4_journal_stop(handle);
3080 3081 3082 3083 3084 3085 3086 3087
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
3088
 * Pages can be marked dirty completely asynchronously from ext4's journalling
3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099
 * 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.
 */
3100
static int ext4_journalled_set_page_dirty(struct page *page)
3101 3102 3103 3104 3105
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

3106
static const struct address_space_operations ext4_ordered_aops = {
3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118
	.readpage		= ext4_readpage,
	.readpages		= ext4_readpages,
	.writepage		= ext4_normal_writepage,
	.sync_page		= block_sync_page,
	.write_begin		= ext4_write_begin,
	.write_end		= ext4_ordered_write_end,
	.bmap			= ext4_bmap,
	.invalidatepage		= ext4_invalidatepage,
	.releasepage		= ext4_releasepage,
	.direct_IO		= ext4_direct_IO,
	.migratepage		= buffer_migrate_page,
	.is_partially_uptodate  = block_is_partially_uptodate,
3119 3120
};

3121
static const struct address_space_operations ext4_writeback_aops = {
3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133
	.readpage		= ext4_readpage,
	.readpages		= ext4_readpages,
	.writepage		= ext4_normal_writepage,
	.sync_page		= block_sync_page,
	.write_begin		= ext4_write_begin,
	.write_end		= ext4_writeback_write_end,
	.bmap			= ext4_bmap,
	.invalidatepage		= ext4_invalidatepage,
	.releasepage		= ext4_releasepage,
	.direct_IO		= ext4_direct_IO,
	.migratepage		= buffer_migrate_page,
	.is_partially_uptodate  = block_is_partially_uptodate,
3134 3135
};

3136
static const struct address_space_operations ext4_journalled_aops = {
3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147
	.readpage		= ext4_readpage,
	.readpages		= ext4_readpages,
	.writepage		= ext4_journalled_writepage,
	.sync_page		= block_sync_page,
	.write_begin		= ext4_write_begin,
	.write_end		= ext4_journalled_write_end,
	.set_page_dirty		= ext4_journalled_set_page_dirty,
	.bmap			= ext4_bmap,
	.invalidatepage		= ext4_invalidatepage,
	.releasepage		= ext4_releasepage,
	.is_partially_uptodate  = block_is_partially_uptodate,
3148 3149
};

3150
static const struct address_space_operations ext4_da_aops = {
3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163
	.readpage		= ext4_readpage,
	.readpages		= ext4_readpages,
	.writepage		= ext4_da_writepage,
	.writepages		= ext4_da_writepages,
	.sync_page		= block_sync_page,
	.write_begin		= ext4_da_write_begin,
	.write_end		= ext4_da_write_end,
	.bmap			= ext4_bmap,
	.invalidatepage		= ext4_da_invalidatepage,
	.releasepage		= ext4_releasepage,
	.direct_IO		= ext4_direct_IO,
	.migratepage		= buffer_migrate_page,
	.is_partially_uptodate  = block_is_partially_uptodate,
3164 3165
};

3166
void ext4_set_aops(struct inode *inode)
3167
{
3168 3169 3170 3171
	if (ext4_should_order_data(inode) &&
		test_opt(inode->i_sb, DELALLOC))
		inode->i_mapping->a_ops = &ext4_da_aops;
	else if (ext4_should_order_data(inode))
3172
		inode->i_mapping->a_ops = &ext4_ordered_aops;
3173 3174 3175
	else if (ext4_should_writeback_data(inode) &&
		 test_opt(inode->i_sb, DELALLOC))
		inode->i_mapping->a_ops = &ext4_da_aops;
3176 3177
	else if (ext4_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext4_writeback_aops;
3178
	else
3179
		inode->i_mapping->a_ops = &ext4_journalled_aops;
3180 3181 3182
}

/*
3183
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3184 3185 3186 3187
 * 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.
 */
3188
int ext4_block_truncate_page(handle_t *handle,
3189 3190
		struct address_space *mapping, loff_t from)
{
3191
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3192
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
A
Aneesh Kumar K.V 已提交
3193 3194
	unsigned blocksize, length, pos;
	ext4_lblk_t iblock;
3195 3196
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
3197
	struct page *page;
3198 3199
	int err = 0;

3200 3201 3202 3203
	page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
	if (!page)
		return -EINVAL;

3204 3205 3206 3207 3208 3209 3210 3211 3212
	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) &&
3213
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
3214
		zero_user(page, offset, length);
3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238
		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");
3239
		ext4_get_block(inode, iblock, bh, 0);
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259
		/* 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;
	}

3260
	if (ext4_should_journal_data(inode)) {
3261
		BUFFER_TRACE(bh, "get write access");
3262
		err = ext4_journal_get_write_access(handle, bh);
3263 3264 3265 3266
		if (err)
			goto unlock;
	}

3267
	zero_user(page, offset, length);
3268 3269 3270 3271

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

	err = 0;
3272 3273
	if (ext4_should_journal_data(inode)) {
		err = ext4_journal_dirty_metadata(handle, bh);
3274
	} else {
3275
		if (ext4_should_order_data(inode))
3276
			err = ext4_jbd2_file_inode(handle, inode);
3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299
		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;
}

/**
3300
 *	ext4_find_shared - find the indirect blocks for partial truncation.
3301 3302
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
3303
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
3304 3305 3306
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
3307
 *	This is a helper function used by ext4_truncate().
3308 3309 3310 3311 3312 3313 3314
 *
 *	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
3315
 *	past the truncation point is possible until ext4_truncate()
3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333
 *	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).  */

3334
static Indirect *ext4_find_shared(struct inode *inode, int depth,
A
Aneesh Kumar K.V 已提交
3335
			ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
3336 3337 3338 3339 3340 3341 3342 3343
{
	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--)
		;
3344
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
3345 3346 3347 3348 3349 3350 3351 3352 3353 3354
	/* 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;
3355
	for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366
		;
	/*
	 * 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;
3367
		/* Nope, don't do this in ext4.  Must leave the tree intact */
3368 3369 3370 3371 3372 3373
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

3374
	while (partial > p) {
3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389
		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.
 */
3390 3391
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
3392 3393 3394 3395 3396
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
3397 3398
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			ext4_journal_dirty_metadata(handle, bh);
3399
		}
3400 3401
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
3402 3403
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
3404
			ext4_journal_get_write_access(handle, bh);
3405 3406 3407 3408 3409
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
3410
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
3411
	 * on them.  We've already detached each block from the file, so
3412
	 * bforget() in jbd2_journal_forget() should be safe.
3413
	 *
3414
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
3415 3416 3417 3418
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
A
Aneesh Kumar K.V 已提交
3419
			struct buffer_head *tbh;
3420 3421

			*p = 0;
A
Aneesh Kumar K.V 已提交
3422 3423
			tbh = sb_find_get_block(inode->i_sb, nr);
			ext4_forget(handle, 0, inode, tbh, nr);
3424 3425 3426
		}
	}

3427
	ext4_free_blocks(handle, inode, block_to_free, count, 0);
3428 3429 3430
}

/**
3431
 * ext4_free_data - free a list of data blocks
3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448
 * @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.
 */
3449
static void ext4_free_data(handle_t *handle, struct inode *inode,
3450 3451 3452
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
3453
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
3454 3455 3456 3457
	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 */
3458
	ext4_fsblk_t nr;		    /* Current block # */
3459 3460 3461 3462 3463 3464
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
3465
		err = ext4_journal_get_write_access(handle, this_bh);
3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482
		/* 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 {
3483
				ext4_clear_blocks(handle, inode, this_bh,
3484 3485 3486 3487 3488 3489 3490 3491 3492 3493
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
3494
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
3495 3496 3497
				  count, block_to_free_p, p);

	if (this_bh) {
3498
		BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513

		/*
		 * The buffer head should have an attached journal head at this
		 * point. However, if the data is corrupted and an indirect
		 * block pointed to itself, it would have been detached when
		 * the block was cleared. Check for this instead of OOPSing.
		 */
		if (bh2jh(this_bh))
			ext4_journal_dirty_metadata(handle, this_bh);
		else
			ext4_error(inode->i_sb, __func__,
				   "circular indirect block detected, "
				   "inode=%lu, block=%llu",
				   inode->i_ino,
				   (unsigned long long) this_bh->b_blocknr);
3514 3515 3516 3517
	}
}

/**
3518
 *	ext4_free_branches - free an array of branches
3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529
 *	@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.
 */
3530
static void ext4_free_branches(handle_t *handle, struct inode *inode,
3531 3532 3533
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
3534
	ext4_fsblk_t nr;
3535 3536 3537 3538 3539 3540 3541
	__le32 *p;

	if (is_handle_aborted(handle))
		return;

	if (depth--) {
		struct buffer_head *bh;
3542
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556
		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) {
3557
				ext4_error(inode->i_sb, "ext4_free_branches",
3558
					   "Read failure, inode=%lu, block=%llu",
3559 3560 3561 3562 3563 3564
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
3565
			ext4_free_branches(handle, inode, bh,
3566 3567 3568
					(__le32 *) bh->b_data,
					(__le32 *) bh->b_data + addr_per_block,
					depth);
3569 3570 3571 3572 3573

			/*
			 * 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
3574
			 * jbd2_journal_revoke().
3575 3576 3577
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
3578
			 * transaction then jbd2_journal_forget() will simply
3579
			 * brelse() it.  That means that if the underlying
3580
			 * block is reallocated in ext4_get_block(),
3581 3582 3583 3584 3585 3586 3587 3588
			 * 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.
			 */
3589
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609

			/*
			 * 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)) {
3610 3611
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
3612 3613
			}

3614
			ext4_free_blocks(handle, inode, nr, 1, 1);
3615 3616 3617 3618 3619 3620 3621

			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");
3622
				if (!ext4_journal_get_write_access(handle,
3623 3624 3625
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
3626 3627
					"call ext4_journal_dirty_metadata");
					ext4_journal_dirty_metadata(handle,
3628 3629 3630 3631 3632 3633 3634
								    parent_bh);
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
3635
		ext4_free_data(handle, inode, parent_bh, first, last);
3636 3637 3638
	}
}

3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651
int ext4_can_truncate(struct inode *inode)
{
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return 0;
	if (S_ISREG(inode->i_mode))
		return 1;
	if (S_ISDIR(inode->i_mode))
		return 1;
	if (S_ISLNK(inode->i_mode))
		return !ext4_inode_is_fast_symlink(inode);
	return 0;
}

3652
/*
3653
 * ext4_truncate()
3654
 *
3655 3656
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672
 * 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
3673
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
3674
 * that this inode's truncate did not complete and it will again call
3675 3676
 * 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
3677
 * that's fine - as long as they are linked from the inode, the post-crash
3678
 * ext4_truncate() run will find them and release them.
3679
 */
3680
void ext4_truncate(struct inode *inode)
3681 3682
{
	handle_t *handle;
3683
	struct ext4_inode_info *ei = EXT4_I(inode);
3684
	__le32 *i_data = ei->i_data;
3685
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3686
	struct address_space *mapping = inode->i_mapping;
A
Aneesh Kumar K.V 已提交
3687
	ext4_lblk_t offsets[4];
3688 3689 3690 3691
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
A
Aneesh Kumar K.V 已提交
3692
	ext4_lblk_t last_block;
3693 3694
	unsigned blocksize = inode->i_sb->s_blocksize;

3695
	if (!ext4_can_truncate(inode))
3696 3697
		return;

A
Aneesh Kumar K.V 已提交
3698
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
3699
		ext4_ext_truncate(inode);
A
Aneesh Kumar K.V 已提交
3700 3701
		return;
	}
A
Alex Tomas 已提交
3702

3703
	handle = start_transaction(inode);
3704
	if (IS_ERR(handle))
3705 3706 3707
		return;		/* AKPM: return what? */

	last_block = (inode->i_size + blocksize-1)
3708
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
3709

3710 3711 3712
	if (inode->i_size & (blocksize - 1))
		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
			goto out_stop;
3713

3714
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726
	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.
	 */
3727
	if (ext4_orphan_add(handle, inode))
3728 3729
		goto out_stop;

3730 3731 3732 3733 3734
	/*
	 * From here we block out all ext4_get_block() callers who want to
	 * modify the block allocation tree.
	 */
	down_write(&ei->i_data_sem);
3735

3736
	ext4_discard_preallocations(inode);
3737

3738 3739 3740 3741 3742
	/*
	 * 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
3743
	 * ext4 *really* writes onto the disk inode.
3744 3745 3746 3747
	 */
	ei->i_disksize = inode->i_size;

	if (n == 1) {		/* direct blocks */
3748 3749
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
3750 3751 3752
		goto do_indirects;
	}

3753
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
3754 3755 3756 3757
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
3758
			ext4_free_branches(handle, inode, NULL,
3759 3760 3761 3762 3763 3764 3765 3766 3767
					   &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");
3768
			ext4_free_branches(handle, inode, partial->bh,
3769 3770 3771 3772 3773 3774
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
3775
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
3776 3777 3778 3779 3780 3781 3782 3783 3784 3785
				   (__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:
3786
		nr = i_data[EXT4_IND_BLOCK];
3787
		if (nr) {
3788 3789
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
3790
		}
3791 3792
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
3793
		if (nr) {
3794 3795
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
3796
		}
3797 3798
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
3799
		if (nr) {
3800 3801
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
3802
		}
3803
	case EXT4_TIND_BLOCK:
3804 3805 3806
		;
	}

3807
	up_write(&ei->i_data_sem);
K
Kalpak Shah 已提交
3808
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3809
	ext4_mark_inode_dirty(handle, inode);
3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821

	/*
	 * 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
3822
	 * ext4_delete_inode(), and we allow that function to clean up the
3823 3824 3825
	 * orphan info for us.
	 */
	if (inode->i_nlink)
3826
		ext4_orphan_del(handle, inode);
3827

3828
	ext4_journal_stop(handle);
3829 3830 3831
}

/*
3832
 * ext4_get_inode_loc returns with an extra refcount against the inode's
3833 3834 3835 3836
 * 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.
 */
3837 3838
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
3839
{
3840 3841 3842 3843 3844 3845 3846 3847 3848
	struct ext4_group_desc	*gdp;
	struct buffer_head	*bh;
	struct super_block	*sb = inode->i_sb;
	ext4_fsblk_t		block;
	int			inodes_per_block, inode_offset;

	iloc->bh = 0;
	if (!ext4_valid_inum(sb, inode->i_ino))
		return -EIO;
3849

3850 3851 3852
	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
	if (!gdp)
3853 3854
		return -EIO;

3855 3856 3857 3858 3859 3860 3861 3862 3863 3864
	/*
	 * Figure out the offset within the block group inode table
	 */
	inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
	inode_offset = ((inode->i_ino - 1) %
			EXT4_INODES_PER_GROUP(sb));
	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);

	bh = sb_getblk(sb, block);
3865
	if (!bh) {
3866 3867 3868
		ext4_error(sb, "ext4_get_inode_loc", "unable to read "
			   "inode block - inode=%lu, block=%llu",
			   inode->i_ino, block);
3869 3870 3871 3872
		return -EIO;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
3873 3874 3875 3876 3877 3878 3879 3880 3881 3882

		/*
		 * If the buffer has the write error flag, we have failed
		 * to write out another inode in the same block.  In this
		 * case, we don't have to read the block because we may
		 * read the old inode data successfully.
		 */
		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
			set_buffer_uptodate(bh);

3883 3884 3885 3886 3887 3888 3889 3890 3891 3892 3893 3894 3895
		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;
3896
			int i, start;
3897

3898
			start = inode_offset & ~(inodes_per_block - 1);
3899

3900 3901
			/* Is the inode bitmap in cache? */
			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913
			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;
			}
3914
			for (i = start; i < start + inodes_per_block; i++) {
3915 3916
				if (i == inode_offset)
					continue;
3917
				if (ext4_test_bit(i, bitmap_bh->b_data))
3918 3919 3920
					break;
			}
			brelse(bitmap_bh);
3921
			if (i == start + inodes_per_block) {
3922 3923 3924 3925 3926 3927 3928 3929 3930
				/* 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:
3931 3932 3933 3934 3935 3936 3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
		/*
		 * If we need to do any I/O, try to pre-readahead extra
		 * blocks from the inode table.
		 */
		if (EXT4_SB(sb)->s_inode_readahead_blks) {
			ext4_fsblk_t b, end, table;
			unsigned num;

			table = ext4_inode_table(sb, gdp);
			/* Make sure s_inode_readahead_blks is a power of 2 */
			while (EXT4_SB(sb)->s_inode_readahead_blks &
			       (EXT4_SB(sb)->s_inode_readahead_blks-1))
				EXT4_SB(sb)->s_inode_readahead_blks = 
				   (EXT4_SB(sb)->s_inode_readahead_blks &
				    (EXT4_SB(sb)->s_inode_readahead_blks-1));
			b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
			if (table > b)
				b = table;
			end = b + EXT4_SB(sb)->s_inode_readahead_blks;
			num = EXT4_INODES_PER_GROUP(sb);
			if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
				num -= le16_to_cpu(gdp->bg_itable_unused);
			table += num / inodes_per_block;
			if (end > table)
				end = table;
			while (b <= end)
				sb_breadahead(sb, b++);
		}

3961 3962 3963 3964 3965 3966 3967 3968 3969 3970
		/*
		 * 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)) {
3971 3972 3973
			ext4_error(sb, __func__,
				   "unable to read inode block - inode=%lu, "
				   "block=%llu", inode->i_ino, block);
3974 3975 3976 3977 3978 3979 3980 3981 3982
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

3983
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3984 3985
{
	/* We have all inode data except xattrs in memory here. */
3986 3987
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
3988 3989
}

3990
void ext4_set_inode_flags(struct inode *inode)
3991
{
3992
	unsigned int flags = EXT4_I(inode)->i_flags;
3993 3994

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3995
	if (flags & EXT4_SYNC_FL)
3996
		inode->i_flags |= S_SYNC;
3997
	if (flags & EXT4_APPEND_FL)
3998
		inode->i_flags |= S_APPEND;
3999
	if (flags & EXT4_IMMUTABLE_FL)
4000
		inode->i_flags |= S_IMMUTABLE;
4001
	if (flags & EXT4_NOATIME_FL)
4002
		inode->i_flags |= S_NOATIME;
4003
	if (flags & EXT4_DIRSYNC_FL)
4004 4005 4006
		inode->i_flags |= S_DIRSYNC;
}

4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024
/* 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;
}
4025 4026 4027 4028
static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
					struct ext4_inode_info *ei)
{
	blkcnt_t i_blocks ;
A
Aneesh Kumar K.V 已提交
4029 4030
	struct inode *inode = &(ei->vfs_inode);
	struct super_block *sb = inode->i_sb;
4031 4032 4033 4034 4035 4036

	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
				EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
		/* we are using combined 48 bit field */
		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
					le32_to_cpu(raw_inode->i_blocks_lo);
A
Aneesh Kumar K.V 已提交
4037 4038 4039 4040 4041 4042
		if (ei->i_flags & EXT4_HUGE_FILE_FL) {
			/* i_blocks represent file system block size */
			return i_blocks  << (inode->i_blkbits - 9);
		} else {
			return i_blocks;
		}
4043 4044 4045 4046
	} else {
		return le32_to_cpu(raw_inode->i_blocks_lo);
	}
}
4047

4048
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4049
{
4050 4051
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
4052
	struct ext4_inode_info *ei;
4053
	struct buffer_head *bh;
4054 4055
	struct inode *inode;
	long ret;
4056 4057
	int block;

4058 4059 4060 4061 4062 4063 4064
	inode = iget_locked(sb, ino);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;

	ei = EXT4_I(inode);
T
Theodore Ts'o 已提交
4065
#ifdef CONFIG_EXT4_FS_POSIX_ACL
4066 4067
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
4068 4069
#endif

4070 4071
	ret = __ext4_get_inode_loc(inode, &iloc, 0);
	if (ret < 0)
4072 4073
		goto bad_inode;
	bh = iloc.bh;
4074
	raw_inode = ext4_raw_inode(&iloc);
4075 4076 4077
	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);
4078
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093
		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);

	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 ||
4094
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4095
			/* this inode is deleted */
4096
			brelse(bh);
4097
			ret = -ESTALE;
4098 4099 4100 4101 4102 4103 4104 4105
			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. */
	}
	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4106
	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4107
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4108
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4109
	    cpu_to_le32(EXT4_OS_HURD)) {
B
Badari Pulavarty 已提交
4110 4111
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4112
	}
4113
	inode->i_size = ext4_isize(raw_inode);
4114 4115 4116 4117 4118 4119 4120
	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!
	 */
4121
	for (block = 0; block < EXT4_N_BLOCKS; block++)
4122 4123 4124
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

4125
	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4126
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4127
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4128
		    EXT4_INODE_SIZE(inode->i_sb)) {
4129
			brelse(bh);
4130
			ret = -EIO;
4131
			goto bad_inode;
4132
		}
4133 4134
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
4135 4136
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
4137 4138
		} else {
			__le32 *magic = (void *)raw_inode +
4139
					EXT4_GOOD_OLD_INODE_SIZE +
4140
					ei->i_extra_isize;
4141 4142
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
4143 4144 4145 4146
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
4147 4148 4149 4150 4151
	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);

4152 4153 4154 4155 4156 4157 4158
	inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
		if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
			inode->i_version |=
			(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
	}

4159
	if (S_ISREG(inode->i_mode)) {
4160 4161 4162
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
4163
	} else if (S_ISDIR(inode->i_mode)) {
4164 4165
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
4166
	} else if (S_ISLNK(inode->i_mode)) {
4167 4168
		if (ext4_inode_is_fast_symlink(inode))
			inode->i_op = &ext4_fast_symlink_inode_operations;
4169
		else {
4170 4171
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
4172 4173
		}
	} else {
4174
		inode->i_op = &ext4_special_inode_operations;
4175 4176 4177 4178 4179 4180 4181
		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])));
	}
4182
	brelse(iloc.bh);
4183
	ext4_set_inode_flags(inode);
4184 4185
	unlock_new_inode(inode);
	return inode;
4186 4187

bad_inode:
4188 4189
	iget_failed(inode);
	return ERR_PTR(ret);
4190 4191
}

4192 4193 4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204
static int ext4_inode_blocks_set(handle_t *handle,
				struct ext4_inode *raw_inode,
				struct ext4_inode_info *ei)
{
	struct inode *inode = &(ei->vfs_inode);
	u64 i_blocks = inode->i_blocks;
	struct super_block *sb = inode->i_sb;

	if (i_blocks <= ~0U) {
		/*
		 * i_blocks can be represnted in a 32 bit variable
		 * as multiple of 512 bytes
		 */
A
Aneesh Kumar K.V 已提交
4205
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4206
		raw_inode->i_blocks_high = 0;
A
Aneesh Kumar K.V 已提交
4207
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4208 4209 4210 4211 4212 4213
		return 0;
	}
	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
		return -EFBIG;

	if (i_blocks <= 0xffffffffffffULL) {
4214 4215 4216 4217
		/*
		 * i_blocks can be represented in a 48 bit variable
		 * as multiple of 512 bytes
		 */
A
Aneesh Kumar K.V 已提交
4218
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4219
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
A
Aneesh Kumar K.V 已提交
4220
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4221
	} else {
A
Aneesh Kumar K.V 已提交
4222 4223 4224 4225 4226
		ei->i_flags |= EXT4_HUGE_FILE_FL;
		/* i_block is stored in file system block size */
		i_blocks = i_blocks >> (inode->i_blkbits - 9);
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4227
	}
4228
	return 0;
4229 4230
}

4231 4232 4233 4234 4235 4236 4237
/*
 * 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.
 */
4238
static int ext4_do_update_inode(handle_t *handle,
4239
				struct inode *inode,
4240
				struct ext4_iloc *iloc)
4241
{
4242 4243
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
4244 4245 4246 4247 4248
	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. */
4249 4250
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4251

4252
	ext4_get_inode_flags(ei);
4253
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4254
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4255 4256 4257 4258 4259 4260
		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
 */
4261
		if (!ei->i_dtime) {
4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278
			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);
K
Kalpak Shah 已提交
4279 4280 4281 4282 4283 4284

	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);

4285 4286
	if (ext4_inode_blocks_set(handle, raw_inode, ei))
		goto out_brelse;
4287
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4288 4289
	/* clear the migrate flag in the raw_inode */
	raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
4290 4291
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
4292 4293
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
4294
	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4295 4296 4297 4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310
	ext4_isize_set(raw_inode, ei->i_disksize);
	if (ei->i_disksize > 0x7fffffffULL) {
		struct super_block *sb = inode->i_sb;
		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)) {
			/* If this is the first large file
			 * created, add a flag to the superblock.
			 */
			err = ext4_journal_get_write_access(handle,
					EXT4_SB(sb)->s_sbh);
			if (err)
				goto out_brelse;
			ext4_update_dynamic_rev(sb);
			EXT4_SET_RO_COMPAT_FEATURE(sb,
4311
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4312 4313 4314 4315
			sb->s_dirt = 1;
			handle->h_sync = 1;
			err = ext4_journal_dirty_metadata(handle,
					EXT4_SB(sb)->s_sbh);
4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329
		}
	}
	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;
		}
4330
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
4331 4332
		raw_inode->i_block[block] = ei->i_data[block];

4333 4334 4335 4336 4337
	raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
	if (ei->i_extra_isize) {
		if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
			raw_inode->i_version_hi =
			cpu_to_le32(inode->i_version >> 32);
4338
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4339 4340
	}

4341

4342 4343
	BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
	rc = ext4_journal_dirty_metadata(handle, bh);
4344 4345
	if (!err)
		err = rc;
4346
	ei->i_state &= ~EXT4_STATE_NEW;
4347 4348

out_brelse:
4349
	brelse(bh);
4350
	ext4_std_error(inode->i_sb, err);
4351 4352 4353 4354
	return err;
}

/*
4355
 * ext4_write_inode()
4356 4357 4358 4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369 4370 4371
 *
 * 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
4372
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388
 * 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.
 */
4389
int ext4_write_inode(struct inode *inode, int wait)
4390 4391 4392 4393
{
	if (current->flags & PF_MEMALLOC)
		return 0;

4394
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
4395
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4396 4397 4398 4399 4400 4401 4402
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

4403
	return ext4_force_commit(inode->i_sb);
4404 4405 4406
}

/*
4407
 * ext4_setattr()
4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420
 *
 * 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.)
 *
4421 4422 4423 4424 4425 4426 4427 4428
 * Another thing we have to assure is that if we are in ordered mode
 * and inode is still attached to the committing transaction, we must
 * we start writeout of all the dirty pages which are being truncated.
 * This way we are sure that all the data written in the previous
 * transaction are already on disk (truncate waits for pages under
 * writeback).
 *
 * Called with inode->i_mutex down.
4429
 */
4430
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442 4443 4444 4445
{
	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) */
4446 4447
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
4448 4449 4450 4451 4452 4453
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
		if (error) {
4454
			ext4_journal_stop(handle);
4455 4456 4457 4458 4459 4460 4461 4462
			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;
4463 4464
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
4465 4466
	}

4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477
	if (attr->ia_valid & ATTR_SIZE) {
		if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
				error = -EFBIG;
				goto err_out;
			}
		}
	}

4478 4479 4480 4481
	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

4482
		handle = ext4_journal_start(inode, 3);
4483 4484 4485 4486 4487
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

4488 4489 4490
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
4491 4492
		if (!error)
			error = rc;
4493
		ext4_journal_stop(handle);
4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509

		if (ext4_should_order_data(inode)) {
			error = ext4_begin_ordered_truncate(inode,
							    attr->ia_size);
			if (error) {
				/* Do as much error cleanup as possible */
				handle = ext4_journal_start(inode, 3);
				if (IS_ERR(handle)) {
					ext4_orphan_del(NULL, inode);
					goto err_out;
				}
				ext4_orphan_del(handle, inode);
				ext4_journal_stop(handle);
				goto err_out;
			}
		}
4510 4511 4512 4513
	}

	rc = inode_setattr(inode, attr);

4514
	/* If inode_setattr's call to ext4_truncate failed to get a
4515 4516 4517
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
4518
		ext4_orphan_del(NULL, inode);
4519 4520

	if (!rc && (ia_valid & ATTR_MODE))
4521
		rc = ext4_acl_chmod(inode);
4522 4523

err_out:
4524
	ext4_std_error(inode->i_sb, error);
4525 4526 4527 4528 4529
	if (!error)
		error = rc;
	return error;
}

4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555
int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
		 struct kstat *stat)
{
	struct inode *inode;
	unsigned long delalloc_blocks;

	inode = dentry->d_inode;
	generic_fillattr(inode, stat);

	/*
	 * We can't update i_blocks if the block allocation is delayed
	 * otherwise in the case of system crash before the real block
	 * allocation is done, we will have i_blocks inconsistent with
	 * on-disk file blocks.
	 * We always keep i_blocks updated together with real
	 * allocation. But to not confuse with user, stat
	 * will return the blocks that include the delayed allocation
	 * blocks for this file.
	 */
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

	stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
	return 0;
}
4556

4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584
static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
				      int chunk)
{
	int indirects;

	/* if nrblocks are contiguous */
	if (chunk) {
		/*
		 * With N contiguous data blocks, it need at most
		 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
		 * 2 dindirect blocks
		 * 1 tindirect block
		 */
		indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
		return indirects + 3;
	}
	/*
	 * if nrblocks are not contiguous, worse case, each block touch
	 * a indirect block, and each indirect block touch a double indirect
	 * block, plus a triple indirect block
	 */
	indirects = nrblocks * 2 + 1;
	return indirects;
}

static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
	if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
4585 4586
		return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
	return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4587
}
4588

4589
/*
4590 4591 4592
 * Account for index blocks, block groups bitmaps and block group
 * descriptor blocks if modify datablocks and index blocks
 * worse case, the indexs blocks spread over different block groups
4593
 *
4594 4595 4596
 * If datablocks are discontiguous, they are possible to spread over
 * different block groups too. If they are contiugous, with flexbg,
 * they could still across block group boundary.
4597
 *
4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644
 * Also account for superblock, inode, quota and xattr blocks
 */
int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
	int groups, gdpblocks;
	int idxblocks;
	int ret = 0;

	/*
	 * How many index blocks need to touch to modify nrblocks?
	 * The "Chunk" flag indicating whether the nrblocks is
	 * physically contiguous on disk
	 *
	 * For Direct IO and fallocate, they calls get_block to allocate
	 * one single extent at a time, so they could set the "Chunk" flag
	 */
	idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);

	ret = idxblocks;

	/*
	 * Now let's see how many group bitmaps and group descriptors need
	 * to account
	 */
	groups = idxblocks;
	if (chunk)
		groups += 1;
	else
		groups += nrblocks;

	gdpblocks = groups;
	if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
		groups = EXT4_SB(inode->i_sb)->s_groups_count;
	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;

	/* bitmaps and block group descriptor blocks */
	ret += groups + gdpblocks;

	/* Blocks for super block, inode, quota and xattr blocks */
	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);

	return ret;
}

/*
 * Calulate the total number of credits to reserve to fit
4645 4646
 * the modification of a single pages into a single transaction,
 * which may include multiple chunks of block allocations.
4647
 *
4648
 * This could be called via ext4_write_begin()
4649
 *
4650
 * We need to consider the worse case, when
4651
 * one new block per extent.
4652
 */
A
Alex Tomas 已提交
4653
int ext4_writepage_trans_blocks(struct inode *inode)
4654
{
4655
	int bpp = ext4_journal_blocks_per_page(inode);
4656 4657
	int ret;

4658
	ret = ext4_meta_trans_blocks(inode, bpp, 0);
A
Alex Tomas 已提交
4659

4660
	/* Account for data blocks for journalled mode */
4661
	if (ext4_should_journal_data(inode))
4662
		ret += bpp;
4663 4664
	return ret;
}
4665 4666 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679

/*
 * Calculate the journal credits for a chunk of data modification.
 *
 * This is called from DIO, fallocate or whoever calling
 * ext4_get_blocks_wrap() to map/allocate a chunk of contigous disk blocks.
 *
 * journal buffers for data blocks are not included here, as DIO
 * and fallocate do no need to journal data buffers.
 */
int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
{
	return ext4_meta_trans_blocks(inode, nrblocks, 1);
}

4680
/*
4681
 * The caller must have previously called ext4_reserve_inode_write().
4682 4683
 * Give this, we know that the caller already has write access to iloc->bh.
 */
4684 4685
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
4686 4687 4688
{
	int err = 0;

4689 4690 4691
	if (test_opt(inode->i_sb, I_VERSION))
		inode_inc_iversion(inode);

4692 4693 4694
	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

4695
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4696
	err = ext4_do_update_inode(handle, inode, iloc);
4697 4698 4699 4700 4701 4702 4703 4704 4705 4706
	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
4707 4708
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
4709 4710 4711
{
	int err = 0;
	if (handle) {
4712
		err = ext4_get_inode_loc(inode, iloc);
4713 4714
		if (!err) {
			BUFFER_TRACE(iloc->bh, "get_write_access");
4715
			err = ext4_journal_get_write_access(handle, iloc->bh);
4716 4717 4718 4719 4720 4721
			if (err) {
				brelse(iloc->bh);
				iloc->bh = NULL;
			}
		}
	}
4722
	ext4_std_error(inode->i_sb, err);
4723 4724 4725
	return err;
}

4726 4727 4728 4729
/*
 * Expand an inode by new_extra_isize bytes.
 * Returns 0 on success or negative error number on failure.
 */
A
Aneesh Kumar K.V 已提交
4730 4731 4732 4733
static int ext4_expand_extra_isize(struct inode *inode,
				   unsigned int new_extra_isize,
				   struct ext4_iloc iloc,
				   handle_t *handle)
4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760
{
	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);
}

4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781
/*
 * 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.
 */
4782
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4783
{
4784
	struct ext4_iloc iloc;
4785 4786 4787
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
4788 4789

	might_sleep();
4790
	err = ext4_reserve_inode_write(handle, inode, &iloc);
4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806
	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;
A
Aneesh Kumar K.V 已提交
4807 4808
				if (mnt_count !=
					le16_to_cpu(sbi->s_es->s_mnt_count)) {
4809
					ext4_warning(inode->i_sb, __func__,
4810 4811 4812
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
A
Aneesh Kumar K.V 已提交
4813 4814
					mnt_count =
					  le16_to_cpu(sbi->s_es->s_mnt_count);
4815 4816 4817 4818
				}
			}
		}
	}
4819
	if (!err)
4820
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4821 4822 4823 4824
	return err;
}

/*
4825
 * ext4_dirty_inode() is called from __mark_inode_dirty()
4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837
 *
 * 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.
 */
4838
void ext4_dirty_inode(struct inode *inode)
4839
{
4840
	handle_t *current_handle = ext4_journal_current_handle();
4841 4842
	handle_t *handle;

4843
	handle = ext4_journal_start(inode, 2);
4844 4845 4846 4847 4848 4849
	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",
4850
		       __func__);
4851 4852 4853
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
4854
		ext4_mark_inode_dirty(handle, inode);
4855
	}
4856
	ext4_journal_stop(handle);
4857 4858 4859 4860 4861 4862 4863 4864
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
4865
 * ext4_reserve_inode_write, this leaves behind no bh reference and
4866 4867 4868
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
4869
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
4870
{
4871
	struct ext4_iloc iloc;
4872 4873 4874

	int err = 0;
	if (handle) {
4875
		err = ext4_get_inode_loc(inode, &iloc);
4876 4877
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
4878
			err = jbd2_journal_get_write_access(handle, iloc.bh);
4879
			if (!err)
4880
				err = ext4_journal_dirty_metadata(handle,
4881 4882 4883 4884
								  iloc.bh);
			brelse(iloc.bh);
		}
	}
4885
	ext4_std_error(inode->i_sb, err);
4886 4887 4888 4889
	return err;
}
#endif

4890
int ext4_change_inode_journal_flag(struct inode *inode, int val)
4891 4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905
{
	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.
	 */

4906
	journal = EXT4_JOURNAL(inode);
4907
	if (is_journal_aborted(journal))
4908 4909
		return -EROFS;

4910 4911
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
4912 4913 4914 4915 4916 4917 4918 4919 4920 4921

	/*
	 * 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)
4922
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
4923
	else
4924 4925
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
4926

4927
	jbd2_journal_unlock_updates(journal);
4928 4929 4930

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

4931
	handle = ext4_journal_start(inode, 1);
4932 4933 4934
	if (IS_ERR(handle))
		return PTR_ERR(handle);

4935
	err = ext4_mark_inode_dirty(handle, inode);
4936
	handle->h_sync = 1;
4937 4938
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
4939 4940 4941

	return err;
}
4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952

static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
{
	return !buffer_mapped(bh);
}

int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{
	loff_t size;
	unsigned long len;
	int ret = -EINVAL;
4953
	void *fsdata;
4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991
	struct file *file = vma->vm_file;
	struct inode *inode = file->f_path.dentry->d_inode;
	struct address_space *mapping = inode->i_mapping;

	/*
	 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
	 * get i_mutex because we are already holding mmap_sem.
	 */
	down_read(&inode->i_alloc_sem);
	size = i_size_read(inode);
	if (page->mapping != mapping || size <= page_offset(page)
	    || !PageUptodate(page)) {
		/* page got truncated from under us? */
		goto out_unlock;
	}
	ret = 0;
	if (PageMappedToDisk(page))
		goto out_unlock;

	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;

	if (page_has_buffers(page)) {
		/* return if we have all the buffers mapped */
		if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
				       ext4_bh_unmapped))
			goto out_unlock;
	}
	/*
	 * OK, we need to fill the hole... Do write_begin write_end
	 * to do block allocation/reservation.We are not holding
	 * inode.i__mutex here. That allow * parallel write_begin,
	 * write_end call. lock_page prevent this from happening
	 * on the same page though
	 */
	ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
4992
			len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
4993 4994 4995
	if (ret < 0)
		goto out_unlock;
	ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
4996
			len, len, page, fsdata);
4997 4998 4999 5000 5001 5002 5003
	if (ret < 0)
		goto out_unlock;
	ret = 0;
out_unlock:
	up_read(&inode->i_alloc_sem);
	return ret;
}