inode.c 149.1 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>
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#include <linux/mpage.h>
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#include <linux/namei.h>
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#include <linux/uio.h>
#include <linux/bio.h>
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#include "ext4_jbd2.h"
41 42
#include "xattr.h"
#include "acl.h"
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#include "ext4_extents.h"
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45 46
#define MPAGE_DA_EXTENT_TAIL 0x01

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static inline int ext4_begin_ordered_truncate(struct inode *inode,
					      loff_t new_size)
{
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	return jbd2_journal_begin_ordered_truncate(
					EXT4_SB(inode->i_sb)->s_journal,
					&EXT4_I(inode)->jinode,
					new_size);
54 55
}

56 57
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)
62
{
63
	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);
}

/*
70
 * 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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 *
 * If the handle isn't valid we're not journaling so there's nothing to do.
79
 */
80 81
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;

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	if (!ext4_handle_valid(handle))
		return 0;

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	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))) {
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		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;
146

147
	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 (!ext4_handle_valid(handle))
		return 0;
	if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
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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)
195
{
196
	BUG_ON(EXT4_JOURNAL(inode) == NULL);
197
	jbd_debug(2, "restarting handle %p\n", handle);
198
	return ext4_journal_restart(handle, blocks_for_truncate(inode));
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}

/*
 * Called at the last iput() if i_nlink is zero.
 */
204
void ext4_delete_inode(struct inode *inode)
205 206
{
	handle_t *handle;
207
	int err;
208

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	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.
		 */
224
		ext4_orphan_del(NULL, inode);
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		goto no_delete;
	}

	if (IS_SYNC(inode))
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		ext4_handle_sync(handle);
230
	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;
	}
237
	if (inode->i_blocks)
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		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.
	 */
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	if (!ext4_handle_has_enough_credits(handle, 3)) {
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		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;
		}
	}

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	/*
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	 * Kill off the orphan record which ext4_truncate created.
261
	 * AKPM: I think this can be inside the above `if'.
262
	 * Note that ext4_orphan_del() has to be able to cope with the
263
	 * deletion of a non-existent orphan - this is because we don't
264
	 * 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)
334
{
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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;
348
	} else if ((i_block -= direct_blocks) < indirect_blocks) {
349
		offsets[n++] = EXT4_IND_BLOCK;
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		offsets[n++] = i_block;
		final = ptrs;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
353
		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) {
358
		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 {
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		ext4_warning(inode->i_sb, "ext4_block_to_path",
365
				"block %lu > max in inode %lu",
366
				i_block + direct_blocks +
367
				indirect_blocks + double_blocks, inode->i_ino);
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	}
	if (boundary)
		*boundary = final - 1 - (i_block & (ptrs - 1));
	return n;
}

/**
375
 *	ext4_get_branch - read the chain of indirect blocks leading to data
376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399
 *	@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).
400 401
 *
 *      Need to be called with
402
 *      down_read(&EXT4_I(inode)->i_data_sem)
403
 */
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static Indirect *ext4_get_branch(struct inode *inode, int depth,
				 ext4_lblk_t  *offsets,
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				 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 */
414
	add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
415 416 417 418 419 420
	if (!p->key)
		goto no_block;
	while (--depth) {
		bh = sb_bread(sb, le32_to_cpu(p->key));
		if (!bh)
			goto failure;
421
		add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
422 423 424 425 426 427 428 429 430 431 432 433 434
		/* Reader: end */
		if (!p->key)
			goto no_block;
	}
	return NULL;

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

/**
435
 *	ext4_find_near - find a place for allocation with sufficient locality
436 437 438
 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
439
 *	This function returns the preferred place for block allocation.
440 441 442 443 444 445 446 447 448 449 450 451 452 453
 *	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.
 */
454
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
455
{
456
	struct ext4_inode_info *ei = EXT4_I(inode);
457
	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
458
	__le32 *p;
459
	ext4_fsblk_t bg_start;
460
	ext4_fsblk_t last_block;
461
	ext4_grpblk_t colour;
462 463 464 465 466 467 468 469 470 471 472 473 474 475 476

	/* 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.
	 */
477
	bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
478 479 480 481
	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) *
482
			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
483 484
	else
		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
485 486 487 488
	return bg_start + colour;
}

/**
489
 *	ext4_find_goal - find a preferred place for allocation.
490 491 492 493
 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
494
 *	Normally this function find the preferred place for block allocation,
495
 *	returns it.
496
 */
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Aneesh Kumar K.V 已提交
497
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
498
		Indirect *partial)
499 500
{
	/*
501
	 * XXX need to get goal block from mballoc's data structures
502 503
	 */

504
	return ext4_find_near(inode, partial);
505 506 507
}

/**
508
 *	ext4_blks_to_allocate: Look up the block map and count the number
509 510 511 512 513 514 515 516 517 518
 *	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.
 */
519
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
520 521
		int blocks_to_boundary)
{
522
	unsigned int count = 0;
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	/*
	 * 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;
}

/**
546
 *	ext4_alloc_blocks: multiple allocate blocks needed for a branch
547 548 549 550 551 552 553 554
 *	@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
 */
555
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
556 557 558
				ext4_lblk_t iblock, ext4_fsblk_t goal,
				int indirect_blks, int blks,
				ext4_fsblk_t new_blocks[4], int *err)
559
{
560
	struct ext4_allocation_request ar;
561
	int target, i;
562
	unsigned long count = 0, blk_allocated = 0;
563
	int index = 0;
564
	ext4_fsblk_t current_block = 0;
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	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)
	 */
575 576 577
	/* first we try to allocate the indirect blocks */
	target = indirect_blks;
	while (target > 0) {
578 579
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
580 581
		current_block = ext4_new_meta_blocks(handle, inode,
							goal, &count, err);
582 583 584 585 586 587 588 589 590
		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}
591 592 593 594 595 596 597 598 599
		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);
600
			break;
601
		}
602 603
	}

604 605 606 607 608
	target = blks - count ;
	blk_allocated = count;
	if (!target)
		goto allocated;
	/* Now allocate data blocks */
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	memset(&ar, 0, sizeof(ar));
	ar.inode = inode;
	ar.goal = goal;
	ar.len = target;
	ar.logical = iblock;
	if (S_ISREG(inode->i_mode))
		/* enable in-core preallocation only for regular files */
		ar.flags = EXT4_MB_HINT_DATA;

	current_block = ext4_mb_new_blocks(handle, &ar, err);

620 621 622 623 624 625 626 627 628 629 630 631 632 633 634
	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;
		}
635
		blk_allocated += ar.len;
636 637
	}
allocated:
638
	/* total number of blocks allocated for direct blocks */
639
	ret = blk_allocated;
640 641 642
	*err = 0;
	return ret;
failed_out:
643
	for (i = 0; i < index; i++)
644
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
645 646 647 648
	return ret;
}

/**
649
 *	ext4_alloc_branch - allocate and set up a chain of blocks.
650 651 652 653 654 655 656 657 658 659
 *	@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
660
 *	the same format as ext4_get_branch() would do. We are calling it after
661 662
 *	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
663
 *	picture as after the successful ext4_get_block(), except that in one
664 665 666 667 668 669
 *	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
670
 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
671 672
 *	as described above and return 0.
 */
673
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
674 675 676
				ext4_lblk_t iblock, int indirect_blks,
				int *blks, ext4_fsblk_t goal,
				ext4_lblk_t *offsets, Indirect *branch)
677 678 679 680 681 682
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
683 684
	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
685

686
	num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
				*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");
705
		err = ext4_journal_get_create_access(handle, bh);
706 707 708 709 710 711 712 713 714 715
		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;
716
		if (n == indirect_blks) {
717 718 719 720 721 722 723 724 725 726 727 728 729
			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);

730 731
		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
		err = ext4_handle_dirty_metadata(handle, inode, bh);
732 733 734 735 736 737 738 739
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
740
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
741
		ext4_journal_forget(handle, branch[i].bh);
742
	}
743
	for (i = 0; i < indirect_blks; i++)
744
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
745

746
	ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
747 748 749 750 751

	return err;
}

/**
752
 * ext4_splice_branch - splice the allocated branch onto inode.
753 754 755
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
756
 *	ext4_alloc_branch)
757 758 759 760 761 762 763 764
 * @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.
 */
765
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
766
			ext4_lblk_t block, Indirect *where, int num, int blks)
767 768 769
{
	int i;
	int err = 0;
770
	ext4_fsblk_t current_block;
771 772 773 774 775 776 777 778

	/*
	 * 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");
779
		err = ext4_journal_get_write_access(handle, where->bh);
780 781 782 783 784 785 786 787 788 789 790 791 792 793
		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++)
794
			*(where->p + i) = cpu_to_le32(current_block++);
795 796 797 798
	}

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

K
Kalpak Shah 已提交
799
	inode->i_ctime = ext4_current_time(inode);
800
	ext4_mark_inode_dirty(handle, inode);
801 802 803 804 805 806 807 808 809

	/* 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
810
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
811 812
		 */
		jbd_debug(5, "splicing indirect only\n");
813 814
		BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
		err = ext4_handle_dirty_metadata(handle, inode, where->bh);
815 816 817 818 819 820 821 822 823 824 825 826 827
		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++) {
828
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
829
		ext4_journal_forget(handle, where[i].bh);
830 831
		ext4_free_blocks(handle, inode,
					le32_to_cpu(where[i-1].key), 1, 0);
832
	}
833
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854

	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.
855 856 857
 *
 *
 * Need to be called with
858 859
 * 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)
860
 */
861 862 863 864
static int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
				  ext4_lblk_t iblock, unsigned int maxblocks,
				  struct buffer_head *bh_result,
				  int create, int extend_disksize)
865 866
{
	int err = -EIO;
A
Aneesh Kumar K.V 已提交
867
	ext4_lblk_t offsets[4];
868 869
	Indirect chain[4];
	Indirect *partial;
870
	ext4_fsblk_t goal;
871 872 873
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
874
	struct ext4_inode_info *ei = EXT4_I(inode);
875
	int count = 0;
876
	ext4_fsblk_t first_block = 0;
877
	loff_t disksize;
878 879


A
Alex Tomas 已提交
880
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
881
	J_ASSERT(handle != NULL || create == 0);
A
Aneesh Kumar K.V 已提交
882 883
	depth = ext4_block_to_path(inode, iblock, offsets,
					&blocks_to_boundary);
884 885 886 887

	if (depth == 0)
		goto out;

888
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
889 890 891 892 893 894 895 896

	/* 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) {
897
			ext4_fsblk_t blk;
898 899 900 901 902 903 904 905

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

			if (blk == first_block + count)
				count++;
			else
				break;
		}
906
		goto got_it;
907 908 909 910 911 912 913
	}

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

	/*
914
	 * Okay, we need to do block allocation.
915
	*/
916
	goal = ext4_find_goal(inode, iblock, partial);
917 918 919 920 921 922 923 924

	/* 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.
	 */
925
	count = ext4_blks_to_allocate(partial, indirect_blks,
926 927
					maxblocks, blocks_to_boundary);
	/*
928
	 * Block out ext4_truncate while we alter the tree
929
	 */
930 931 932
	err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
					&count, goal,
					offsets + (partial - chain), partial);
933 934

	/*
935
	 * The ext4_splice_branch call will free and forget any buffers
936 937 938 939 940 941
	 * 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)
942
		err = ext4_splice_branch(handle, inode, iblock,
943 944
					partial, indirect_blks, count);
	/*
945
	 * i_disksize growing is protected by i_data_sem.  Don't forget to
946
	 * protect it if you're about to implement concurrent
947
	 * ext4_get_block() -bzzz
948
	*/
949 950 951 952 953 954 955
	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;
	}
956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977
	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;
}

978 979 980 981 982 983 984 985 986 987 988
qsize_t ext4_get_reserved_space(struct inode *inode)
{
	unsigned long long total;

	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
	total = EXT4_I(inode)->i_reserved_data_blocks +
		EXT4_I(inode)->i_reserved_meta_blocks;
	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);

	return total;
}
989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
/*
 * 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)
{
1014 1015 1016
	if (!blocks)
		return 0;

1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036
	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;

1037 1038 1039 1040 1041 1042 1043 1044 1045
	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;
	}
1046 1047 1048 1049 1050

	/* 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);
1051 1052 1053 1054 1055 1056 1057

	/*
	 * free those over-booking quota for metadata blocks
	 */

	if (mdb_free)
		vfs_dq_release_reservation_block(inode, mdb_free);
1058 1059
}

1060
/*
1061 1062
 * The ext4_get_blocks_wrap() function try to look up the requested blocks,
 * and returns if the blocks are already mapped.
1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081
 *
 * 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.
 */
1082
int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
1083
			unsigned int max_blocks, struct buffer_head *bh,
1084
			int create, int extend_disksize, int flag)
1085 1086
{
	int retval;
1087 1088 1089

	clear_buffer_mapped(bh);

1090 1091 1092 1093 1094 1095 1096 1097
	/*
	 * 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);
1098
	} else {
1099 1100
		retval = ext4_get_blocks_handle(handle,
				inode, block, max_blocks, bh, 0, 0);
1101
	}
1102
	up_read((&EXT4_I(inode)->i_data_sem));
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115

	/* 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))
1116 1117 1118
		return retval;

	/*
1119 1120 1121 1122
	 * 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.
1123 1124
	 */
	down_write((&EXT4_I(inode)->i_data_sem));
1125 1126 1127 1128 1129 1130 1131 1132 1133

	/*
	 * 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;
1134 1135 1136 1137
	/*
	 * We need to check for EXT4 here because migrate
	 * could have changed the inode type in between
	 */
1138 1139 1140 1141 1142 1143
	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);
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153

		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;
		}
1154
	}
1155 1156 1157 1158 1159 1160 1161 1162 1163

	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))
1164
			ext4_da_update_reserve_space(inode, retval);
1165 1166
	}

1167
	up_write((&EXT4_I(inode)->i_data_sem));
1168 1169 1170
	return retval;
}

1171 1172 1173
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096

1174 1175
int ext4_get_block(struct inode *inode, sector_t iblock,
		   struct buffer_head *bh_result, int create)
1176
{
1177
	handle_t *handle = ext4_journal_current_handle();
J
Jan Kara 已提交
1178
	int ret = 0, started = 0;
1179
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1180
	int dio_credits;
1181

J
Jan Kara 已提交
1182 1183 1184 1185
	if (create && !handle) {
		/* Direct IO write... */
		if (max_blocks > DIO_MAX_BLOCKS)
			max_blocks = DIO_MAX_BLOCKS;
1186 1187
		dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
		handle = ext4_journal_start(inode, dio_credits);
J
Jan Kara 已提交
1188
		if (IS_ERR(handle)) {
1189
			ret = PTR_ERR(handle);
J
Jan Kara 已提交
1190
			goto out;
1191
		}
J
Jan Kara 已提交
1192
		started = 1;
1193 1194
	}

J
Jan Kara 已提交
1195
	ret = ext4_get_blocks_wrap(handle, inode, iblock,
1196
					max_blocks, bh_result, create, 0, 0);
J
Jan Kara 已提交
1197 1198 1199
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
1200
	}
J
Jan Kara 已提交
1201 1202 1203
	if (started)
		ext4_journal_stop(handle);
out:
1204 1205 1206 1207 1208 1209
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
1210
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1211
				ext4_lblk_t block, int create, int *errp)
1212 1213 1214 1215 1216 1217 1218 1219 1220
{
	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
1221
	err = ext4_get_blocks_wrap(handle, inode, block, 1,
1222
					&dummy, create, 1, 0);
1223
	/*
1224
	 * ext4_get_blocks_handle() returns number of blocks
1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241
	 * 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
1242
			J_ASSERT(handle != NULL);
1243 1244 1245 1246 1247

			/*
			 * 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
1248
			 * writes use ext4_get_block instead, so it's not a
1249 1250 1251 1252
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1253
			fatal = ext4_journal_get_create_access(handle, bh);
1254
			if (!fatal && !buffer_uptodate(bh)) {
1255
				memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1256 1257 1258
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1259 1260
			BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
			err = ext4_handle_dirty_metadata(handle, inode, bh);
1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276
			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;
}

1277
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1278
			       ext4_lblk_t block, int create, int *err)
1279
{
1280
	struct buffer_head *bh;
1281

1282
	bh = ext4_getblk(handle, inode, block, create, err);
1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
	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;
}

1296 1297 1298 1299 1300 1301 1302
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))
1303 1304 1305 1306 1307 1308 1309
{
	struct buffer_head *bh;
	unsigned block_start, block_end;
	unsigned blocksize = head->b_size;
	int err, ret = 0;
	struct buffer_head *next;

1310 1311 1312
	for (bh = head, block_start = 0;
	     ret == 0 && (bh != head || !block_start);
	     block_start = block_end, bh = next)
1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330
	{
		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
1331
 * close off a transaction and start a new one between the ext4_get_block()
1332
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1333 1334
 * prepare_write() is the right place.
 *
1335 1336
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1337 1338 1339 1340
 * 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.
 *
1341
 * By accident, ext4 can be reentered when a transaction is open via
1342 1343 1344 1345 1346 1347
 * 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.
 *
1348
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1349 1350 1351 1352 1353 1354 1355 1356 1357
 * 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;
1358
	return ext4_journal_get_write_access(handle, bh);
1359 1360
}

N
Nick Piggin 已提交
1361 1362 1363
static int ext4_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
1364
{
1365
	struct inode *inode = mapping->host;
1366
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1367 1368
	handle_t *handle;
	int retries = 0;
1369
	struct page *page;
N
Nick Piggin 已提交
1370
 	pgoff_t index;
1371
	unsigned from, to;
N
Nick Piggin 已提交
1372

1373 1374 1375 1376
	trace_mark(ext4_write_begin,
		   "dev %s ino %lu pos %llu len %u flags %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, flags);
N
Nick Piggin 已提交
1377
 	index = pos >> PAGE_CACHE_SHIFT;
1378 1379
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;
1380 1381

retry:
1382 1383 1384 1385
	handle = ext4_journal_start(inode, needed_blocks);
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out;
1386
	}
1387

1388 1389 1390 1391
	/* We cannot recurse into the filesystem as the transaction is already
	 * started */
	flags |= AOP_FLAG_NOFS;

1392
	page = grab_cache_page_write_begin(mapping, index, flags);
1393 1394 1395 1396 1397 1398 1399
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
	*pagep = page;

N
Nick Piggin 已提交
1400
	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1401
				ext4_get_block);
N
Nick Piggin 已提交
1402 1403

	if (!ret && ext4_should_journal_data(inode)) {
1404 1405 1406
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
N
Nick Piggin 已提交
1407 1408

	if (ret) {
1409
		unlock_page(page);
1410
		ext4_journal_stop(handle);
1411
		page_cache_release(page);
1412 1413 1414 1415 1416 1417 1418
		/*
		 * 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
1419 1420
	}

1421
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1422
		goto retry;
1423
out:
1424 1425 1426
	return ret;
}

N
Nick Piggin 已提交
1427 1428
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1429 1430 1431 1432
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1433
	return ext4_handle_dirty_metadata(handle, NULL, bh);
1434 1435 1436 1437 1438 1439
}

/*
 * 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().
 *
1440
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1441 1442
 * buffers are managed internally.
 */
N
Nick Piggin 已提交
1443 1444 1445 1446
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)
1447
{
1448
	handle_t *handle = ext4_journal_current_handle();
1449
	struct inode *inode = mapping->host;
1450 1451
	int ret = 0, ret2;

1452 1453 1454 1455
	trace_mark(ext4_ordered_write_end,
		   "dev %s ino %lu pos %llu len %u copied %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, copied);
1456
	ret = ext4_jbd2_file_inode(handle, inode);
1457 1458 1459 1460

	if (ret == 0) {
		loff_t new_i_size;

N
Nick Piggin 已提交
1461
		new_i_size = pos + copied;
1462 1463 1464 1465 1466 1467 1468 1469 1470
		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);
		}

1471
		ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1472
							page, fsdata);
1473 1474 1475
		copied = ret2;
		if (ret2 < 0)
			ret = ret2;
1476
	}
1477
	ret2 = ext4_journal_stop(handle);
1478 1479
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1480 1481

	return ret ? ret : copied;
1482 1483
}

N
Nick Piggin 已提交
1484 1485 1486 1487
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)
1488
{
1489
	handle_t *handle = ext4_journal_current_handle();
1490
	struct inode *inode = mapping->host;
1491 1492 1493
	int ret = 0, ret2;
	loff_t new_i_size;

1494 1495 1496 1497
	trace_mark(ext4_writeback_write_end,
		   "dev %s ino %lu pos %llu len %u copied %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, copied);
N
Nick Piggin 已提交
1498
	new_i_size = pos + copied;
1499 1500 1501 1502 1503 1504 1505 1506
	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);
	}
1507

1508
	ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1509
							page, fsdata);
1510 1511 1512
	copied = ret2;
	if (ret2 < 0)
		ret = ret2;
1513

1514
	ret2 = ext4_journal_stop(handle);
1515 1516
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1517 1518

	return ret ? ret : copied;
1519 1520
}

N
Nick Piggin 已提交
1521 1522 1523 1524
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)
1525
{
1526
	handle_t *handle = ext4_journal_current_handle();
N
Nick Piggin 已提交
1527
	struct inode *inode = mapping->host;
1528 1529
	int ret = 0, ret2;
	int partial = 0;
N
Nick Piggin 已提交
1530
	unsigned from, to;
1531
	loff_t new_i_size;
1532

1533 1534 1535 1536
	trace_mark(ext4_journalled_write_end,
		   "dev %s ino %lu pos %llu len %u copied %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, copied);
N
Nick Piggin 已提交
1537 1538 1539 1540 1541 1542 1543 1544
	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);
	}
1545 1546

	ret = walk_page_buffers(handle, page_buffers(page), from,
N
Nick Piggin 已提交
1547
				to, &partial, write_end_fn);
1548 1549
	if (!partial)
		SetPageUptodate(page);
1550 1551
	new_i_size = pos + copied;
	if (new_i_size > inode->i_size)
N
Nick Piggin 已提交
1552
		i_size_write(inode, pos+copied);
1553
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1554 1555
	if (new_i_size > EXT4_I(inode)->i_disksize) {
		ext4_update_i_disksize(inode, new_i_size);
1556
		ret2 = ext4_mark_inode_dirty(handle, inode);
1557 1558 1559
		if (!ret)
			ret = ret2;
	}
N
Nick Piggin 已提交
1560

1561
	unlock_page(page);
1562
	ret2 = ext4_journal_stop(handle);
1563 1564
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1565 1566 1567
	page_cache_release(page);

	return ret ? ret : copied;
1568
}
1569 1570 1571

static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
{
A
Aneesh Kumar K.V 已提交
1572
	int retries = 0;
1573 1574
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	unsigned long md_needed, mdblocks, total = 0;
1575 1576 1577 1578 1579 1580

	/*
	 * 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
1581
repeat:
1582 1583 1584 1585 1586 1587 1588 1589
	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;

1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
	/*
	 * Make quota reservation here to prevent quota overflow
	 * later. Real quota accounting is done at pages writeout
	 * time.
	 */
	if (vfs_dq_reserve_block(inode, total)) {
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
		return -EDQUOT;
	}

1600
	if (ext4_claim_free_blocks(sbi, total)) {
1601
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
A
Aneesh Kumar K.V 已提交
1602 1603 1604 1605
		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
			yield();
			goto repeat;
		}
1606
		vfs_dq_release_reservation_block(inode, total);
1607 1608 1609 1610 1611 1612 1613 1614 1615
		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 */
}

1616
static void ext4_da_release_space(struct inode *inode, int to_free)
1617 1618 1619 1620
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	int total, mdb, mdb_free, release;

1621 1622 1623
	if (!to_free)
		return;		/* Nothing to release, exit */

1624
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639

	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;
	}

1640
	/* recalculate the number of metablocks still need to be reserved */
1641
	total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1642 1643 1644 1645 1646 1647 1648 1649
	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;

1650 1651
	/* update fs dirty blocks counter for truncate case */
	percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1652 1653

	/* update per-inode reservations */
1654 1655
	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
	EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1656 1657 1658 1659

	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);
1660 1661

	vfs_dq_release_reservation_block(inode, release);
1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681
}

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);
1682
	ext4_da_release_space(page->mapping->host, to_release);
1683
}
1684

1685 1686 1687 1688 1689 1690 1691 1692 1693 1694
/*
 * 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;
1695
	int io_done;
1696
	int pages_written;
1697
	int retval;
1698 1699 1700 1701
};

/*
 * mpage_da_submit_io - walks through extent of pages and try to write
1702
 * them with writepage() call back
1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715
 *
 * @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)
{
1716
	long pages_skipped;
1717 1718 1719 1720 1721
	struct pagevec pvec;
	unsigned long index, end;
	int ret = 0, err, nr_pages, i;
	struct inode *inode = mpd->inode;
	struct address_space *mapping = inode->i_mapping;
1722 1723

	BUG_ON(mpd->next_page <= mpd->first_page);
1724 1725 1726 1727 1728 1729
	/*
	 * We need to start from the first_page to the next_page - 1
	 * to make sure we also write the mapped dirty buffer_heads.
	 * If we look at mpd->lbh.b_blocknr we would only be looking
	 * at the currently mapped buffer_heads.
	 */
1730 1731 1732
	index = mpd->first_page;
	end = mpd->next_page - 1;

1733
	pagevec_init(&pvec, 0);
1734
	while (index <= end) {
1735
		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1736 1737 1738 1739 1740
		if (nr_pages == 0)
			break;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

1741 1742 1743 1744 1745 1746 1747 1748
			index = page->index;
			if (index > end)
				break;
			index++;

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

1749
			pages_skipped = mpd->wbc->pages_skipped;
1750
			err = mapping->a_ops->writepage(page, mpd->wbc);
1751 1752 1753 1754 1755
			if (!err && (pages_skipped == mpd->wbc->pages_skipped))
				/*
				 * have successfully written the page
				 * without skipping the same
				 */
1756
				mpd->pages_written++;
1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788
			/*
			 * 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;
1789
	pgoff_t index, end;
1790 1791 1792 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 1826 1827 1828 1829 1830 1831
	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);
1832 1833 1834 1835 1836 1837 1838
					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;
1839
				} else if (buffer_mapped(bh))
1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
					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);
}

1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898
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;
}

1899 1900 1901 1902 1903 1904 1905
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",
1906
			(long long)percpu_counter_sum(&sbi->s_freeblocks_counter));
1907
	printk(KERN_EMERG "dirty_blocks=%lld\n",
1908
			(long long)percpu_counter_sum(&sbi->s_dirtyblocks_counter));
1909
	printk(KERN_EMERG "Block reservation details\n");
1910
	printk(KERN_EMERG "i_reserved_data_blocks=%u\n",
1911
			EXT4_I(inode)->i_reserved_data_blocks);
1912
	printk(KERN_EMERG "i_reserved_meta_blocks=%u\n",
1913 1914 1915 1916
			EXT4_I(inode)->i_reserved_meta_blocks);
	return;
}

1917 1918 1919 1920 1921 1922 1923 1924 1925
/*
 * 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.
 *
 */
1926
static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
1927
{
1928
	int err = 0;
A
Aneesh Kumar K.V 已提交
1929
	struct buffer_head new;
1930
	struct buffer_head *lbh = &mpd->lbh;
1931
	sector_t next;
1932 1933 1934 1935 1936

	/*
	 * We consider only non-mapped and non-allocated blocks
	 */
	if (buffer_mapped(lbh) && !buffer_delay(lbh))
1937
		return 0;
1938 1939 1940
	new.b_state = lbh->b_state;
	new.b_blocknr = 0;
	new.b_size = lbh->b_size;
1941
	next = lbh->b_blocknr;
1942 1943 1944 1945 1946
	/*
	 * If we didn't accumulate anything
	 * to write simply return
	 */
	if (!new.b_size)
1947
		return 0;
1948
	err = mpd->get_block(mpd->inode, next, &new, 1);
1949 1950 1951 1952 1953 1954 1955 1956 1957
	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;
1958 1959 1960 1961 1962 1963 1964

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

1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980
		/*
		 * 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
1981
		if (err == -ENOSPC) {
1982
			ext4_print_free_blocks(mpd->inode);
A
Aneesh Kumar K.V 已提交
1983
		}
1984 1985 1986 1987 1988
		/* invlaidate all the pages */
		ext4_da_block_invalidatepages(mpd, next,
				lbh->b_size >> mpd->inode->i_blkbits);
		return err;
	}
1989
	BUG_ON(new.b_size == 0);
1990

1991 1992
	if (buffer_new(&new))
		__unmap_underlying_blocks(mpd->inode, &new);
1993

1994 1995 1996 1997 1998 1999
	/*
	 * 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);
2000

2001
	return 0;
2002 2003
}

2004 2005
#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
		(1 << BH_Delay) | (1 << BH_Unwritten))
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

/*
 * 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;
2020 2021 2022
	size_t b_size = bh->b_size;
	struct buffer_head *lbh = &mpd->lbh;
	int nrblocks = lbh->b_size >> mpd->inode->i_blkbits;
2023

2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
	/* 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 */
		}
	}
2046 2047 2048 2049 2050
	/*
	 * First block in the extent
	 */
	if (lbh->b_size == 0) {
		lbh->b_blocknr = logical;
2051
		lbh->b_size = b_size;
2052 2053 2054 2055
		lbh->b_state = bh->b_state & BH_FLAGS;
		return;
	}

2056
	next = lbh->b_blocknr + nrblocks;
2057 2058 2059 2060
	/*
	 * Can we merge the block to our big extent?
	 */
	if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) {
2061
		lbh->b_size += b_size;
2062 2063 2064
		return;
	}

2065
flush_it:
2066 2067 2068 2069
	/*
	 * We couldn't merge the block to our extent, so we
	 * need to flush current  extent and start new one
	 */
2070 2071
	if (mpage_da_map_blocks(mpd) == 0)
		mpage_da_submit_io(mpd);
2072 2073
	mpd->io_done = 1;
	return;
2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092
}

/*
 * __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;

2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103
	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;
	}
2104 2105 2106 2107 2108 2109
	/*
	 * Can we merge this page to current extent?
	 */
	if (mpd->next_page != page->index) {
		/*
		 * Nope, we can't. So, we map non-allocated blocks
2110
		 * and start IO on them using writepage()
2111 2112
		 */
		if (mpd->next_page != mpd->first_page) {
2113 2114
			if (mpage_da_map_blocks(mpd) == 0)
				mpage_da_submit_io(mpd);
2115 2116 2117 2118 2119 2120 2121
			/*
			 * 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;
2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151
		}

		/*
		 * 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);
2152 2153
		if (mpd->io_done)
			return MPAGE_DA_EXTENT_TAIL;
2154 2155 2156 2157 2158 2159 2160 2161
	} else {
		/*
		 * Page with regular buffer heads, just add all dirty ones
		 */
		head = page_buffers(page);
		bh = head;
		do {
			BUG_ON(buffer_locked(bh));
2162 2163 2164 2165 2166 2167
			/*
			 * We need to try to allocate
			 * unmapped blocks in the same page.
			 * Otherwise we won't make progress
			 * with the page in ext4_da_writepage
			 */
2168 2169
			if (buffer_dirty(bh) &&
				(!buffer_mapped(bh) || buffer_delay(bh))) {
2170
				mpage_add_bh_to_extent(mpd, logical, bh);
2171 2172
				if (mpd->io_done)
					return MPAGE_DA_EXTENT_TAIL;
2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184
			} else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
				/*
				 * mapped dirty buffer. We need to update
				 * the b_state because we look at
				 * b_state in mpage_da_map_blocks. We don't
				 * update b_size because if we find an
				 * unmapped buffer_head later we need to
				 * use the b_state flag of that buffer_head.
				 */
				if (mpd->lbh.b_size == 0)
					mpd->lbh.b_state =
						bh->b_state & BH_FLAGS;
2185
			}
2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206
			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,
2207
			       struct mpage_da_data *mpd)
2208 2209 2210
{
	int ret;

2211
	if (!mpd->get_block)
2212 2213
		return generic_writepages(mapping, wbc);

2214 2215 2216 2217 2218 2219 2220 2221
	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;
2222

2223
	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
2224 2225 2226
	/*
	 * Handle last extent of pages
	 */
2227 2228 2229
	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
		if (mpage_da_map_blocks(mpd) == 0)
			mpage_da_submit_io(mpd);
2230

2231 2232 2233 2234
		mpd->io_done = 1;
		ret = MPAGE_DA_EXTENT_TAIL;
	}
	wbc->nr_to_write -= mpd->pages_written;
2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254
	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.
	 */
2255 2256 2257
	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 */
2258 2259 2260 2261
		/*
		 * XXX: __block_prepare_write() unmaps passed block,
		 * is it OK?
		 */
2262 2263 2264 2265 2266
		ret = ext4_da_reserve_space(inode, 1);
		if (ret)
			/* not enough space to reserve */
			return ret;

2267 2268 2269 2270 2271 2272 2273 2274 2275 2276
		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;
}
2277
#define		EXT4_DELALLOC_RSVED	1
2278 2279 2280
static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
				   struct buffer_head *bh_result, int create)
{
2281
	int ret;
2282 2283 2284 2285
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
	loff_t disksize = EXT4_I(inode)->i_disksize;
	handle_t *handle = NULL;

2286
	handle = ext4_journal_current_handle();
2287 2288 2289
	BUG_ON(!handle);
	ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
			bh_result, create, 0, EXT4_DELALLOC_RSVED);
2290
	if (ret > 0) {
2291

2292 2293
		bh_result->b_size = (ret << inode->i_blkbits);

2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304
		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;
		}

2305 2306 2307 2308 2309 2310 2311 2312 2313
		/*
		 * 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) {
2314 2315 2316
			ext4_update_i_disksize(inode, disksize);
			ret = ext4_mark_inode_dirty(handle, inode);
			return ret;
2317 2318 2319 2320 2321
		}
		ret = 0;
	}
	return ret;
}
2322 2323 2324

static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
{
2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348
	/*
	 * 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;
2349 2350 2351
}

/*
2352 2353 2354 2355
 * 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)
2356
 */
2357 2358 2359 2360
static int ext4_da_writepage(struct page *page,
				struct writeback_control *wbc)
{
	int ret = 0;
2361
	loff_t size;
2362
	unsigned int len;
2363 2364 2365
	struct buffer_head *page_bufs;
	struct inode *inode = page->mapping->host;

2366 2367 2368
	trace_mark(ext4_da_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
2369 2370 2371 2372 2373
	size = i_size_read(inode);
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
2374

2375
	if (page_has_buffers(page)) {
2376
		page_bufs = page_buffers(page);
2377 2378
		if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
					ext4_bh_unmapped_or_delay)) {
2379
			/*
2380 2381
			 * We don't want to do  block allocation
			 * So redirty the page and return
2382 2383 2384
			 * 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
2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420
			 * 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
2421 2422 2423 2424 2425
			 */
			redirty_page_for_writepage(wbc, page);
			unlock_page(page);
			return 0;
		}
2426 2427
		/* now mark the buffer_heads as dirty and uptodate */
		block_commit_write(page, 0, PAGE_CACHE_SIZE);
2428 2429 2430
	}

	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2431
		ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
2432
	else
2433 2434 2435
		ret = block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
2436 2437 2438 2439

	return ret;
}

2440
/*
2441 2442 2443 2444 2445
 * 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.
2446
 */
2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463

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);
}
2464

2465
static int ext4_da_writepages(struct address_space *mapping,
2466
			      struct writeback_control *wbc)
2467
{
2468 2469
	pgoff_t	index;
	int range_whole = 0;
2470
	handle_t *handle = NULL;
2471
	struct mpage_da_data mpd;
2472
	struct inode *inode = mapping->host;
2473
	int no_nrwrite_index_update;
2474 2475
	int pages_written = 0;
	long pages_skipped;
2476
	int range_cyclic, cycled = 1, io_done = 0;
2477 2478
	int needed_blocks, ret = 0, nr_to_writebump = 0;
	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2479

2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493
	trace_mark(ext4_da_writepages,
		   "dev %s ino %lu nr_t_write %ld "
		   "pages_skipped %ld range_start %llu "
		   "range_end %llu nonblocking %d "
		   "for_kupdate %d for_reclaim %d "
		   "for_writepages %d range_cyclic %d",
		   inode->i_sb->s_id, inode->i_ino,
		   wbc->nr_to_write, wbc->pages_skipped,
		   (unsigned long long) wbc->range_start,
		   (unsigned long long) wbc->range_end,
		   wbc->nonblocking, wbc->for_kupdate,
		   wbc->for_reclaim, wbc->for_writepages,
		   wbc->range_cyclic);

2494 2495 2496 2497 2498
	/*
	 * 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
	 */
2499
	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2500
		return 0;
2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514

	/*
	 * If the filesystem has aborted, it is read-only, so return
	 * right away instead of dumping stack traces later on that
	 * will obscure the real source of the problem.  We test
	 * EXT4_MOUNT_ABORT instead of sb->s_flag's MS_RDONLY because
	 * the latter could be true if the filesystem is mounted
	 * read-only, and in that case, ext4_da_writepages should
	 * *never* be called, so if that ever happens, we would want
	 * the stack trace.
	 */
	if (unlikely(sbi->s_mount_opt & EXT4_MOUNT_ABORT))
		return -EROFS;

2515 2516 2517 2518 2519 2520 2521 2522 2523 2524
	/*
	 * 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;
	}
2525 2526
	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
		range_whole = 1;
2527

2528 2529
	range_cyclic = wbc->range_cyclic;
	if (wbc->range_cyclic) {
2530
		index = mapping->writeback_index;
2531 2532 2533 2534 2535 2536
		if (index)
			cycled = 0;
		wbc->range_start = index << PAGE_CACHE_SHIFT;
		wbc->range_end  = LLONG_MAX;
		wbc->range_cyclic = 0;
	} else
2537
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
2538

2539 2540 2541
	mpd.wbc = wbc;
	mpd.inode = mapping->host;

2542 2543 2544 2545 2546 2547 2548 2549
	/*
	 * 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;

2550
retry:
2551
	while (!ret && wbc->nr_to_write > 0) {
2552 2553 2554 2555 2556 2557 2558 2559

		/*
		 * 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));
2560
		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2561

2562 2563 2564 2565
		/* start a new transaction*/
		handle = ext4_journal_start(inode, needed_blocks);
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
2566
			printk(KERN_CRIT "%s: jbd2_start: "
2567 2568 2569
			       "%ld pages, ino %lu; err %d\n", __func__,
				wbc->nr_to_write, inode->i_ino, ret);
			dump_stack();
2570 2571
			goto out_writepages;
		}
2572 2573 2574
		mpd.get_block = ext4_da_get_block_write;
		ret = mpage_da_writepages(mapping, wbc, &mpd);

2575
		ext4_journal_stop(handle);
2576

2577
		if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2578 2579 2580 2581
			/* commit the transaction which would
			 * free blocks released in the transaction
			 * and try again
			 */
2582
			jbd2_journal_force_commit_nested(sbi->s_journal);
2583 2584 2585
			wbc->pages_skipped = pages_skipped;
			ret = 0;
		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
2586 2587 2588 2589
			/*
			 * got one extent now try with
			 * rest of the pages
			 */
2590 2591
			pages_written += mpd.pages_written;
			wbc->pages_skipped = pages_skipped;
2592
			ret = 0;
2593
			io_done = 1;
2594
		} else if (wbc->nr_to_write)
2595 2596 2597 2598 2599 2600
			/*
			 * There is no more writeout needed
			 * or we requested for a noblocking writeout
			 * and we found the device congested
			 */
			break;
2601
	}
2602 2603 2604 2605 2606 2607 2608
	if (!io_done && !cycled) {
		cycled = 1;
		index = 0;
		wbc->range_start = index << PAGE_CACHE_SHIFT;
		wbc->range_end  = mapping->writeback_index - 1;
		goto retry;
	}
2609 2610 2611 2612 2613 2614 2615
	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;
2616
	wbc->range_cyclic = range_cyclic;
2617 2618 2619 2620 2621 2622
	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;
2623

2624
out_writepages:
2625 2626 2627
	if (!no_nrwrite_index_update)
		wbc->no_nrwrite_index_update = 0;
	wbc->nr_to_write -= nr_to_writebump;
2628 2629 2630 2631 2632 2633 2634 2635
	trace_mark(ext4_da_writepage_result,
		   "dev %s ino %lu ret %d pages_written %d "
		   "pages_skipped %ld congestion %d "
		   "more_io %d no_nrwrite_index_update %d",
		   inode->i_sb->s_id, inode->i_ino, ret,
		   pages_written, wbc->pages_skipped,
		   wbc->encountered_congestion, wbc->more_io,
		   wbc->no_nrwrite_index_update);
2636
	return ret;
2637 2638
}

2639 2640 2641 2642 2643 2644 2645 2646 2647
#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
2648
	 * counters can get slightly wrong with percpu_counter_batch getting
2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665
	 * 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;
}

2666 2667 2668 2669
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)
{
2670
	int ret, retries = 0;
2671 2672 2673 2674 2675 2676 2677 2678 2679
	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;
2680 2681 2682 2683 2684 2685 2686

	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;
2687 2688 2689 2690 2691

	trace_mark(ext4_da_write_begin,
		   "dev %s ino %lu pos %llu len %u flags %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, flags);
2692
retry:
2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703
	/*
	 * 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;
	}
2704 2705 2706
	/* We cannot recurse into the filesystem as the transaction is already
	 * started */
	flags |= AOP_FLAG_NOFS;
2707

2708
	page = grab_cache_page_write_begin(mapping, index, flags);
2709 2710 2711 2712 2713
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
2714 2715 2716 2717 2718 2719 2720 2721
	*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);
2722 2723 2724 2725 2726 2727 2728
		/*
		 * 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);
2729 2730
	}

2731 2732
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
2733 2734 2735 2736
out:
	return ret;
}

2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751
/*
 * 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;

2752
	for (i = 0; i < idx; i++)
2753 2754 2755 2756 2757 2758 2759
		bh = bh->b_this_page;

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

2760 2761 2762 2763 2764 2765 2766 2767 2768
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;
2769
	unsigned long start, end;
2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782
	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();
		}
	}
2783

2784 2785 2786 2787
	trace_mark(ext4_da_write_end,
		   "dev %s ino %lu pos %llu len %u copied %u",
		   inode->i_sb->s_id, inode->i_ino,
		   (unsigned long long) pos, len, copied);
2788
	start = pos & (PAGE_CACHE_SIZE - 1);
2789
	end = start + copied - 1;
2790 2791 2792 2793 2794 2795 2796 2797

	/*
	 * 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;
2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808
	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);
2809

2810 2811 2812
				EXT4_I(inode)->i_disksize = new_i_size;
			}
			up_write(&EXT4_I(inode)->i_data_sem);
2813 2814 2815 2816 2817
			/* 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);
2818
		}
2819
	}
2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840
	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;

2841
	ext4_da_page_release_reservation(page, offset);
2842 2843 2844 2845 2846 2847 2848 2849

out:
	ext4_invalidatepage(page, offset);

	return;
}


2850 2851 2852 2853 2854
/*
 * 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
2855
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
2856 2857 2858 2859 2860 2861 2862 2863
 * 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.
 */
2864
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2865 2866 2867 2868 2869
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

2870 2871 2872 2873 2874 2875 2876 2877 2878 2879
	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);
	}

2880
	if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891
		/*
		 * 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.)
		 *
2892
		 * NB. EXT4_STATE_JDATA is not set on files other than
2893 2894 2895 2896 2897 2898
		 * 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.
		 */

2899 2900
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
2901 2902 2903
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
2904 2905 2906 2907 2908

		if (err)
			return 0;
	}

2909
	return generic_block_bmap(mapping, block, ext4_get_block);
2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924
}

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;
}

/*
2925 2926 2927 2928 2929 2930 2931 2932
 * 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.
2933
 *
2934
 * In all journaling modes block_write_full_page() will start the I/O.
2935 2936 2937
 *
 * Problem:
 *
2938 2939
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
2940 2941 2942
 *
 * Similar for:
 *
2943
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
2944
 *
2945
 * Same applies to ext4_get_block().  We will deadlock on various things like
2946
 * lock_journal and i_data_sem
2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976
 *
 * 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.
 *
 */
2977
static int __ext4_normal_writepage(struct page *page,
2978 2979 2980 2981 2982
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;

	if (test_opt(inode->i_sb, NOBH))
2983 2984
		return nobh_writepage(page,
					ext4_normal_get_block_write, wbc);
2985
	else
2986 2987 2988
		return block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
2989 2990
}

2991
static int ext4_normal_writepage(struct page *page,
2992 2993 2994
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
2995 2996 2997
	loff_t size = i_size_read(inode);
	loff_t len;

2998 2999 3000
	trace_mark(ext4_normal_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
3001 3002 3003 3004 3005
	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019

	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));
	}
3020 3021

	if (!ext4_journal_current_handle())
3022
		return __ext4_normal_writepage(page, wbc);
3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034

	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;
3035 3036 3037 3038
	handle_t *handle = NULL;
	int ret = 0;
	int err;

3039 3040
	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
					ext4_normal_get_block_write);
3041 3042 3043 3044 3045 3046 3047 3048 3049
	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);
3050

3051
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
3052 3053
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
3054
		goto out;
3055 3056
	}

3057 3058
	ret = walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
3059

3060 3061 3062 3063
	err = walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, write_end_fn);
	if (ret == 0)
		ret = err;
3064
	err = ext4_journal_stop(handle);
3065 3066 3067
	if (!ret)
		ret = err;

3068 3069 3070 3071 3072 3073
	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:
3074
	unlock_page(page);
3075
out:
3076 3077 3078
	return ret;
}

3079
static int ext4_journalled_writepage(struct page *page,
3080 3081 3082
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
3083 3084
	loff_t size = i_size_read(inode);
	loff_t len;
3085

3086 3087 3088
	trace_mark(ext4_journalled_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
3089 3090 3091 3092 3093
	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107

	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));
	}
3108

3109
	if (ext4_journal_current_handle())
3110 3111
		goto no_write;

3112
	if (PageChecked(page)) {
3113 3114 3115 3116 3117
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
3118
		return __ext4_journalled_writepage(page, wbc);
3119 3120 3121 3122 3123 3124
	} 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.
		 */
3125 3126 3127
		return block_write_full_page(page,
						ext4_normal_get_block_write,
						wbc);
3128 3129 3130 3131
	}
no_write:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
3132
	return 0;
3133 3134
}

3135
static int ext4_readpage(struct file *file, struct page *page)
3136
{
3137
	return mpage_readpage(page, ext4_get_block);
3138 3139 3140
}

static int
3141
ext4_readpages(struct file *file, struct address_space *mapping,
3142 3143
		struct list_head *pages, unsigned nr_pages)
{
3144
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3145 3146
}

3147
static void ext4_invalidatepage(struct page *page, unsigned long offset)
3148
{
3149
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3150 3151 3152 3153 3154 3155 3156

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

3157 3158 3159 3160
	if (journal)
		jbd2_journal_invalidatepage(journal, page, offset);
	else
		block_invalidatepage(page, offset);
3161 3162
}

3163
static int ext4_releasepage(struct page *page, gfp_t wait)
3164
{
3165
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3166 3167 3168 3169

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
3170 3171 3172 3173
	if (journal)
		return jbd2_journal_try_to_free_buffers(journal, page, wait);
	else
		return try_to_free_buffers(page);
3174 3175 3176 3177 3178 3179 3180 3181
}

/*
 * 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
3182 3183
 * 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.
3184
 */
3185
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3186 3187 3188 3189 3190
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
3191
	struct ext4_inode_info *ei = EXT4_I(inode);
J
Jan Kara 已提交
3192
	handle_t *handle;
3193 3194 3195 3196 3197 3198 3199 3200
	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
3201 3202 3203 3204 3205 3206
			/* Credits for sb + inode write */
			handle = ext4_journal_start(inode, 2);
			if (IS_ERR(handle)) {
				ret = PTR_ERR(handle);
				goto out;
			}
3207
			ret = ext4_orphan_add(handle, inode);
J
Jan Kara 已提交
3208 3209 3210 3211
			if (ret) {
				ext4_journal_stop(handle);
				goto out;
			}
3212 3213
			orphan = 1;
			ei->i_disksize = inode->i_size;
J
Jan Kara 已提交
3214
			ext4_journal_stop(handle);
3215 3216 3217 3218 3219
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
3220
				 ext4_get_block, NULL);
3221

J
Jan Kara 已提交
3222
	if (orphan) {
3223 3224
		int err;

J
Jan Kara 已提交
3225 3226 3227 3228 3229 3230 3231 3232 3233 3234
		/* 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)
3235
			ext4_orphan_del(handle, inode);
J
Jan Kara 已提交
3236
		if (ret > 0) {
3237 3238 3239 3240 3241 3242 3243 3244
			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
3245
				 * ext4_mark_inode_dirty() to userspace.  So
3246 3247
				 * ignore it.
				 */
3248
				ext4_mark_inode_dirty(handle, inode);
3249 3250
			}
		}
3251
		err = ext4_journal_stop(handle);
3252 3253 3254 3255 3256 3257 3258 3259
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
3260
 * Pages can be marked dirty completely asynchronously from ext4's journalling
3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271
 * 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.
 */
3272
static int ext4_journalled_set_page_dirty(struct page *page)
3273 3274 3275 3276 3277
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

3278
static const struct address_space_operations ext4_ordered_aops = {
3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290
	.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,
3291 3292
};

3293
static const struct address_space_operations ext4_writeback_aops = {
3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305
	.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,
3306 3307
};

3308
static const struct address_space_operations ext4_journalled_aops = {
3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319
	.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,
3320 3321
};

3322
static const struct address_space_operations ext4_da_aops = {
3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335
	.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,
3336 3337
};

3338
void ext4_set_aops(struct inode *inode)
3339
{
3340 3341 3342 3343
	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))
3344
		inode->i_mapping->a_ops = &ext4_ordered_aops;
3345 3346 3347
	else if (ext4_should_writeback_data(inode) &&
		 test_opt(inode->i_sb, DELALLOC))
		inode->i_mapping->a_ops = &ext4_da_aops;
3348 3349
	else if (ext4_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext4_writeback_aops;
3350
	else
3351
		inode->i_mapping->a_ops = &ext4_journalled_aops;
3352 3353 3354
}

/*
3355
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3356 3357 3358 3359
 * 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.
 */
3360
int ext4_block_truncate_page(handle_t *handle,
3361 3362
		struct address_space *mapping, loff_t from)
{
3363
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3364
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
A
Aneesh Kumar K.V 已提交
3365 3366
	unsigned blocksize, length, pos;
	ext4_lblk_t iblock;
3367 3368
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
3369
	struct page *page;
3370 3371
	int err = 0;

3372 3373 3374 3375
	page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
	if (!page)
		return -EINVAL;

3376 3377 3378 3379 3380 3381 3382 3383 3384
	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) &&
3385
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
3386
		zero_user(page, offset, length);
3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410
		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");
3411
		ext4_get_block(inode, iblock, bh, 0);
3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431
		/* 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;
	}

3432
	if (ext4_should_journal_data(inode)) {
3433
		BUFFER_TRACE(bh, "get write access");
3434
		err = ext4_journal_get_write_access(handle, bh);
3435 3436 3437 3438
		if (err)
			goto unlock;
	}

3439
	zero_user(page, offset, length);
3440 3441 3442 3443

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

	err = 0;
3444
	if (ext4_should_journal_data(inode)) {
3445
		err = ext4_handle_dirty_metadata(handle, inode, bh);
3446
	} else {
3447
		if (ext4_should_order_data(inode))
3448
			err = ext4_jbd2_file_inode(handle, inode);
3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471
		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;
}

/**
3472
 *	ext4_find_shared - find the indirect blocks for partial truncation.
3473 3474
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
3475
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
3476 3477 3478
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
3479
 *	This is a helper function used by ext4_truncate().
3480 3481 3482 3483 3484 3485 3486
 *
 *	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
3487
 *	past the truncation point is possible until ext4_truncate()
3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505
 *	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).  */

3506
static Indirect *ext4_find_shared(struct inode *inode, int depth,
A
Aneesh Kumar K.V 已提交
3507
			ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
3508 3509 3510 3511 3512 3513 3514 3515
{
	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--)
		;
3516
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
3517 3518 3519 3520 3521 3522 3523 3524 3525 3526
	/* 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;
3527
	for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538
		;
	/*
	 * 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;
3539
		/* Nope, don't do this in ext4.  Must leave the tree intact */
3540 3541 3542 3543 3544 3545
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

3546
	while (partial > p) {
3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561
		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.
 */
3562 3563
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
3564 3565 3566 3567 3568
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
3569 3570
			BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
			ext4_handle_dirty_metadata(handle, inode, bh);
3571
		}
3572 3573
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
3574 3575
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
3576
			ext4_journal_get_write_access(handle, bh);
3577 3578 3579 3580 3581
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
3582
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
3583
	 * on them.  We've already detached each block from the file, so
3584
	 * bforget() in jbd2_journal_forget() should be safe.
3585
	 *
3586
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
3587 3588 3589 3590
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
A
Aneesh Kumar K.V 已提交
3591
			struct buffer_head *tbh;
3592 3593

			*p = 0;
A
Aneesh Kumar K.V 已提交
3594 3595
			tbh = sb_find_get_block(inode->i_sb, nr);
			ext4_forget(handle, 0, inode, tbh, nr);
3596 3597 3598
		}
	}

3599
	ext4_free_blocks(handle, inode, block_to_free, count, 0);
3600 3601 3602
}

/**
3603
 * ext4_free_data - free a list of data blocks
3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620
 * @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.
 */
3621
static void ext4_free_data(handle_t *handle, struct inode *inode,
3622 3623 3624
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
3625
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
3626 3627 3628 3629
	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 */
3630
	ext4_fsblk_t nr;		    /* Current block # */
3631 3632 3633 3634 3635 3636
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
3637
		err = ext4_journal_get_write_access(handle, this_bh);
3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654
		/* 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 {
3655
				ext4_clear_blocks(handle, inode, this_bh,
3656 3657 3658 3659 3660 3661 3662 3663 3664 3665
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
3666
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
3667 3668 3669
				  count, block_to_free_p, p);

	if (this_bh) {
3670
		BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
3671 3672 3673 3674 3675 3676 3677

		/*
		 * 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.
		 */
3678
		if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
3679
			ext4_handle_dirty_metadata(handle, inode, this_bh);
3680 3681 3682 3683 3684 3685
		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);
3686 3687 3688 3689
	}
}

/**
3690
 *	ext4_free_branches - free an array of branches
3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701
 *	@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.
 */
3702
static void ext4_free_branches(handle_t *handle, struct inode *inode,
3703 3704 3705
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
3706
	ext4_fsblk_t nr;
3707 3708
	__le32 *p;

3709
	if (ext4_handle_is_aborted(handle))
3710 3711 3712 3713
		return;

	if (depth--) {
		struct buffer_head *bh;
3714
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728
		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) {
3729
				ext4_error(inode->i_sb, "ext4_free_branches",
3730
					   "Read failure, inode=%lu, block=%llu",
3731 3732 3733 3734 3735 3736
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
3737
			ext4_free_branches(handle, inode, bh,
3738 3739 3740
					(__le32 *) bh->b_data,
					(__le32 *) bh->b_data + addr_per_block,
					depth);
3741 3742 3743 3744 3745

			/*
			 * 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
3746
			 * jbd2_journal_revoke().
3747 3748 3749
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
3750
			 * transaction then jbd2_journal_forget() will simply
3751
			 * brelse() it.  That means that if the underlying
3752
			 * block is reallocated in ext4_get_block(),
3753 3754 3755 3756 3757 3758 3759 3760
			 * 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.
			 */
3761
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778

			/*
			 * 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.
			 */
3779
			if (ext4_handle_is_aborted(handle))
3780 3781
				return;
			if (try_to_extend_transaction(handle, inode)) {
3782 3783
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
3784 3785
			}

3786
			ext4_free_blocks(handle, inode, nr, 1, 1);
3787 3788 3789 3790 3791 3792 3793

			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");
3794
				if (!ext4_journal_get_write_access(handle,
3795 3796 3797
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
3798 3799 3800 3801
					"call ext4_handle_dirty_metadata");
					ext4_handle_dirty_metadata(handle,
								   inode,
								   parent_bh);
3802 3803 3804 3805 3806 3807
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
3808
		ext4_free_data(handle, inode, parent_bh, first, last);
3809 3810 3811
	}
}

3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824
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;
}

3825
/*
3826
 * ext4_truncate()
3827
 *
3828 3829
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3830 3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845
 * 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
3846
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
3847
 * that this inode's truncate did not complete and it will again call
3848 3849
 * 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
3850
 * that's fine - as long as they are linked from the inode, the post-crash
3851
 * ext4_truncate() run will find them and release them.
3852
 */
3853
void ext4_truncate(struct inode *inode)
3854 3855
{
	handle_t *handle;
3856
	struct ext4_inode_info *ei = EXT4_I(inode);
3857
	__le32 *i_data = ei->i_data;
3858
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3859
	struct address_space *mapping = inode->i_mapping;
A
Aneesh Kumar K.V 已提交
3860
	ext4_lblk_t offsets[4];
3861 3862 3863 3864
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
A
Aneesh Kumar K.V 已提交
3865
	ext4_lblk_t last_block;
3866 3867
	unsigned blocksize = inode->i_sb->s_blocksize;

3868
	if (!ext4_can_truncate(inode))
3869 3870
		return;

A
Aneesh Kumar K.V 已提交
3871
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
3872
		ext4_ext_truncate(inode);
A
Aneesh Kumar K.V 已提交
3873 3874
		return;
	}
A
Alex Tomas 已提交
3875

3876
	handle = start_transaction(inode);
3877
	if (IS_ERR(handle))
3878 3879 3880
		return;		/* AKPM: return what? */

	last_block = (inode->i_size + blocksize-1)
3881
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
3882

3883 3884 3885
	if (inode->i_size & (blocksize - 1))
		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
			goto out_stop;
3886

3887
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899
	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.
	 */
3900
	if (ext4_orphan_add(handle, inode))
3901 3902
		goto out_stop;

3903 3904 3905 3906 3907
	/*
	 * From here we block out all ext4_get_block() callers who want to
	 * modify the block allocation tree.
	 */
	down_write(&ei->i_data_sem);
3908

3909
	ext4_discard_preallocations(inode);
3910

3911 3912 3913 3914 3915
	/*
	 * 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
3916
	 * ext4 *really* writes onto the disk inode.
3917 3918 3919 3920
	 */
	ei->i_disksize = inode->i_size;

	if (n == 1) {		/* direct blocks */
3921 3922
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
3923 3924 3925
		goto do_indirects;
	}

3926
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
3927 3928 3929 3930
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
3931
			ext4_free_branches(handle, inode, NULL,
3932 3933 3934 3935 3936 3937 3938 3939 3940
					   &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");
3941
			ext4_free_branches(handle, inode, partial->bh,
3942 3943 3944 3945 3946 3947
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
3948
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
3949 3950 3951 3952 3953 3954 3955 3956 3957 3958
				   (__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:
3959
		nr = i_data[EXT4_IND_BLOCK];
3960
		if (nr) {
3961 3962
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
3963
		}
3964 3965
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
3966
		if (nr) {
3967 3968
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
3969
		}
3970 3971
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
3972
		if (nr) {
3973 3974
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
3975
		}
3976
	case EXT4_TIND_BLOCK:
3977 3978 3979
		;
	}

3980
	up_write(&ei->i_data_sem);
K
Kalpak Shah 已提交
3981
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3982
	ext4_mark_inode_dirty(handle, inode);
3983 3984 3985 3986 3987 3988

	/*
	 * In a multi-transaction truncate, we only make the final transaction
	 * synchronous
	 */
	if (IS_SYNC(inode))
3989
		ext4_handle_sync(handle);
3990 3991 3992 3993 3994
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
3995
	 * ext4_delete_inode(), and we allow that function to clean up the
3996 3997 3998
	 * orphan info for us.
	 */
	if (inode->i_nlink)
3999
		ext4_orphan_del(handle, inode);
4000

4001
	ext4_journal_stop(handle);
4002 4003 4004
}

/*
4005
 * ext4_get_inode_loc returns with an extra refcount against the inode's
4006 4007 4008 4009
 * 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.
 */
4010 4011
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
4012
{
4013 4014 4015 4016 4017 4018
	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;

A
Aneesh Kumar K.V 已提交
4019
	iloc->bh = NULL;
4020 4021
	if (!ext4_valid_inum(sb, inode->i_ino))
		return -EIO;
4022

4023 4024 4025
	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
	if (!gdp)
4026 4027
		return -EIO;

4028 4029 4030 4031 4032 4033 4034 4035 4036 4037
	/*
	 * 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);
4038
	if (!bh) {
4039 4040 4041
		ext4_error(sb, "ext4_get_inode_loc", "unable to read "
			   "inode block - inode=%lu, block=%llu",
			   inode->i_ino, block);
4042 4043 4044 4045
		return -EIO;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
4046 4047 4048 4049 4050 4051 4052 4053 4054 4055

		/*
		 * 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);

4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068
		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;
4069
			int i, start;
4070

4071
			start = inode_offset & ~(inodes_per_block - 1);
4072

4073 4074
			/* Is the inode bitmap in cache? */
			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086
			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;
			}
4087
			for (i = start; i < start + inodes_per_block; i++) {
4088 4089
				if (i == inode_offset)
					continue;
4090
				if (ext4_test_bit(i, bitmap_bh->b_data))
4091 4092 4093
					break;
			}
			brelse(bitmap_bh);
4094
			if (i == start + inodes_per_block) {
4095 4096 4097 4098 4099 4100 4101 4102 4103
				/* 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:
4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125
		/*
		 * 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))
4126
				num -= ext4_itable_unused_count(sb, gdp);
4127 4128 4129 4130 4131 4132 4133
			table += num / inodes_per_block;
			if (end > table)
				end = table;
			while (b <= end)
				sb_breadahead(sb, b++);
		}

4134 4135 4136 4137 4138 4139 4140 4141 4142 4143
		/*
		 * 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)) {
4144 4145 4146
			ext4_error(sb, __func__,
				   "unable to read inode block - inode=%lu, "
				   "block=%llu", inode->i_ino, block);
4147 4148 4149 4150 4151 4152 4153 4154 4155
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

4156
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4157 4158
{
	/* We have all inode data except xattrs in memory here. */
4159 4160
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
4161 4162
}

4163
void ext4_set_inode_flags(struct inode *inode)
4164
{
4165
	unsigned int flags = EXT4_I(inode)->i_flags;
4166 4167

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4168
	if (flags & EXT4_SYNC_FL)
4169
		inode->i_flags |= S_SYNC;
4170
	if (flags & EXT4_APPEND_FL)
4171
		inode->i_flags |= S_APPEND;
4172
	if (flags & EXT4_IMMUTABLE_FL)
4173
		inode->i_flags |= S_IMMUTABLE;
4174
	if (flags & EXT4_NOATIME_FL)
4175
		inode->i_flags |= S_NOATIME;
4176
	if (flags & EXT4_DIRSYNC_FL)
4177 4178 4179
		inode->i_flags |= S_DIRSYNC;
}

4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197
/* 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;
}
4198 4199 4200 4201
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
4202 4203
	struct inode *inode = &(ei->vfs_inode);
	struct super_block *sb = inode->i_sb;
4204 4205 4206 4207 4208 4209

	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
4210 4211 4212 4213 4214 4215
		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;
		}
4216 4217 4218 4219
	} else {
		return le32_to_cpu(raw_inode->i_blocks_lo);
	}
}
4220

4221
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4222
{
4223 4224
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
4225
	struct ext4_inode_info *ei;
4226
	struct buffer_head *bh;
4227 4228
	struct inode *inode;
	long ret;
4229 4230
	int block;

4231 4232 4233 4234 4235 4236 4237
	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
4238
#ifdef CONFIG_EXT4_FS_POSIX_ACL
4239 4240
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
4241 4242
#endif

4243 4244
	ret = __ext4_get_inode_loc(inode, &iloc, 0);
	if (ret < 0)
4245 4246
		goto bad_inode;
	bh = iloc.bh;
4247
	raw_inode = ext4_raw_inode(&iloc);
4248 4249 4250
	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);
4251
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266
		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 ||
4267
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4268
			/* this inode is deleted */
4269
			brelse(bh);
4270
			ret = -ESTALE;
4271 4272 4273 4274 4275 4276 4277 4278
			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);
4279
	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4280
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4281
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4282
	    cpu_to_le32(EXT4_OS_HURD)) {
B
Badari Pulavarty 已提交
4283 4284
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4285
	}
4286
	inode->i_size = ext4_isize(raw_inode);
4287 4288 4289 4290 4291 4292 4293
	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!
	 */
4294
	for (block = 0; block < EXT4_N_BLOCKS; block++)
4295 4296 4297
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

4298
	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4299
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4300
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4301
		    EXT4_INODE_SIZE(inode->i_sb)) {
4302
			brelse(bh);
4303
			ret = -EIO;
4304
			goto bad_inode;
4305
		}
4306 4307
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
4308 4309
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
4310 4311
		} else {
			__le32 *magic = (void *)raw_inode +
4312
					EXT4_GOOD_OLD_INODE_SIZE +
4313
					ei->i_extra_isize;
4314 4315
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
4316 4317 4318 4319
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
4320 4321 4322 4323 4324
	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);

4325 4326 4327 4328 4329 4330 4331
	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;
	}

4332
	if (S_ISREG(inode->i_mode)) {
4333 4334 4335
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
4336
	} else if (S_ISDIR(inode->i_mode)) {
4337 4338
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
4339
	} else if (S_ISLNK(inode->i_mode)) {
4340
		if (ext4_inode_is_fast_symlink(inode)) {
4341
			inode->i_op = &ext4_fast_symlink_inode_operations;
4342 4343 4344
			nd_terminate_link(ei->i_data, inode->i_size,
				sizeof(ei->i_data) - 1);
		} else {
4345 4346
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
4347 4348
		}
	} else {
4349
		inode->i_op = &ext4_special_inode_operations;
4350 4351 4352 4353 4354 4355 4356
		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])));
	}
4357
	brelse(iloc.bh);
4358
	ext4_set_inode_flags(inode);
4359 4360
	unlock_new_inode(inode);
	return inode;
4361 4362

bad_inode:
4363 4364
	iget_failed(inode);
	return ERR_PTR(ret);
4365 4366
}

4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379
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
4380
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4381
		raw_inode->i_blocks_high = 0;
A
Aneesh Kumar K.V 已提交
4382
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4383 4384 4385 4386 4387 4388
		return 0;
	}
	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
		return -EFBIG;

	if (i_blocks <= 0xffffffffffffULL) {
4389 4390 4391 4392
		/*
		 * i_blocks can be represented in a 48 bit variable
		 * as multiple of 512 bytes
		 */
A
Aneesh Kumar K.V 已提交
4393
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4394
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
A
Aneesh Kumar K.V 已提交
4395
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4396
	} else {
A
Aneesh Kumar K.V 已提交
4397 4398 4399 4400 4401
		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);
4402
	}
4403
	return 0;
4404 4405
}

4406 4407 4408 4409 4410 4411 4412
/*
 * 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.
 */
4413
static int ext4_do_update_inode(handle_t *handle,
4414
				struct inode *inode,
4415
				struct ext4_iloc *iloc)
4416
{
4417 4418
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
4419 4420 4421 4422 4423
	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. */
4424 4425
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4426

4427
	ext4_get_inode_flags(ei);
4428
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4429
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4430 4431 4432 4433 4434 4435
		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
 */
4436
		if (!ei->i_dtime) {
4437 4438 4439 4440 4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453
			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
4454 4455 4456 4457 4458 4459

	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);

4460 4461
	if (ext4_inode_blocks_set(handle, raw_inode, ei))
		goto out_brelse;
4462
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4463 4464
	/* clear the migrate flag in the raw_inode */
	raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
4465 4466
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
4467 4468
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
4469
	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4470 4471 4472 4473 4474 4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485
	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,
4486
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4487
			sb->s_dirt = 1;
4488 4489
			ext4_handle_sync(handle);
			err = ext4_handle_dirty_metadata(handle, inode,
4490
					EXT4_SB(sb)->s_sbh);
4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504
		}
	}
	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;
		}
4505
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
4506 4507
		raw_inode->i_block[block] = ei->i_data[block];

4508 4509 4510 4511 4512
	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);
4513
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4514 4515
	}

4516 4517
	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
	rc = ext4_handle_dirty_metadata(handle, inode, bh);
4518 4519
	if (!err)
		err = rc;
4520
	ei->i_state &= ~EXT4_STATE_NEW;
4521 4522

out_brelse:
4523
	brelse(bh);
4524
	ext4_std_error(inode->i_sb, err);
4525 4526 4527 4528
	return err;
}

/*
4529
 * ext4_write_inode()
4530 4531 4532 4533 4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545
 *
 * 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
4546
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562
 * 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.
 */
4563
int ext4_write_inode(struct inode *inode, int wait)
4564 4565 4566 4567
{
	if (current->flags & PF_MEMALLOC)
		return 0;

4568
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
4569
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4570 4571 4572 4573 4574 4575 4576
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

4577
	return ext4_force_commit(inode->i_sb);
4578 4579
}

4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598
int __ext4_write_dirty_metadata(struct inode *inode, struct buffer_head *bh)
{
	int err = 0;

	mark_buffer_dirty(bh);
	if (inode && inode_needs_sync(inode)) {
		sync_dirty_buffer(bh);
		if (buffer_req(bh) && !buffer_uptodate(bh)) {
			ext4_error(inode->i_sb, __func__,
				   "IO error syncing inode, "
				   "inode=%lu, block=%llu",
				   inode->i_ino,
				   (unsigned long long)bh->b_blocknr);
			err = -EIO;
		}
	}
	return err;
}

4599
/*
4600
 * ext4_setattr()
4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613
 *
 * 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.)
 *
4614 4615 4616 4617 4618 4619 4620 4621
 * 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.
4622
 */
4623
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638
{
	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) */
4639 4640
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
4641 4642 4643 4644 4645 4646
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
		if (error) {
4647
			ext4_journal_stop(handle);
4648 4649 4650 4651 4652 4653 4654 4655
			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;
4656 4657
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
4658 4659
	}

4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670
	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;
			}
		}
	}

4671 4672 4673 4674
	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

4675
		handle = ext4_journal_start(inode, 3);
4676 4677 4678 4679 4680
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

4681 4682 4683
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
4684 4685
		if (!error)
			error = rc;
4686
		ext4_journal_stop(handle);
4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702

		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;
			}
		}
4703 4704 4705 4706
	}

	rc = inode_setattr(inode, attr);

4707
	/* If inode_setattr's call to ext4_truncate failed to get a
4708 4709 4710
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
4711
		ext4_orphan_del(NULL, inode);
4712 4713

	if (!rc && (ia_valid & ATTR_MODE))
4714
		rc = ext4_acl_chmod(inode);
4715 4716

err_out:
4717
	ext4_std_error(inode->i_sb, error);
4718 4719 4720 4721 4722
	if (!error)
		error = rc;
	return error;
}

4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 4748
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;
}
4749

4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777
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))
4778 4779
		return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
	return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4780
}
4781

4782
/*
4783 4784 4785
 * 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
4786
 *
4787 4788 4789
 * 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.
4790
 *
4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819 4820 4821 4822 4823 4824 4825 4826 4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837
 * 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
4838 4839
 * the modification of a single pages into a single transaction,
 * which may include multiple chunks of block allocations.
4840
 *
4841
 * This could be called via ext4_write_begin()
4842
 *
4843
 * We need to consider the worse case, when
4844
 * one new block per extent.
4845
 */
A
Alex Tomas 已提交
4846
int ext4_writepage_trans_blocks(struct inode *inode)
4847
{
4848
	int bpp = ext4_journal_blocks_per_page(inode);
4849 4850
	int ret;

4851
	ret = ext4_meta_trans_blocks(inode, bpp, 0);
A
Alex Tomas 已提交
4852

4853
	/* Account for data blocks for journalled mode */
4854
	if (ext4_should_journal_data(inode))
4855
		ret += bpp;
4856 4857
	return ret;
}
4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872

/*
 * 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);
}

4873
/*
4874
 * The caller must have previously called ext4_reserve_inode_write().
4875 4876
 * Give this, we know that the caller already has write access to iloc->bh.
 */
4877 4878
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
4879 4880 4881
{
	int err = 0;

4882 4883 4884
	if (test_opt(inode->i_sb, I_VERSION))
		inode_inc_iversion(inode);

4885 4886 4887
	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

4888
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4889
	err = ext4_do_update_inode(handle, inode, iloc);
4890 4891 4892 4893 4894 4895 4896 4897 4898 4899
	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
4900 4901
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
4902
{
4903 4904 4905 4906 4907 4908 4909 4910 4911
	int err;

	err = ext4_get_inode_loc(inode, iloc);
	if (!err) {
		BUFFER_TRACE(iloc->bh, "get_write_access");
		err = ext4_journal_get_write_access(handle, iloc->bh);
		if (err) {
			brelse(iloc->bh);
			iloc->bh = NULL;
4912 4913
		}
	}
4914
	ext4_std_error(inode->i_sb, err);
4915 4916 4917
	return err;
}

4918 4919 4920 4921
/*
 * 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
4922 4923 4924 4925
static int ext4_expand_extra_isize(struct inode *inode,
				   unsigned int new_extra_isize,
				   struct ext4_iloc iloc,
				   handle_t *handle)
4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952
{
	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);
}

4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973
/*
 * 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.
 */
4974
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4975
{
4976
	struct ext4_iloc iloc;
4977 4978 4979
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
4980 4981

	might_sleep();
4982
	err = ext4_reserve_inode_write(handle, inode, &iloc);
4983 4984
	if (ext4_handle_valid(handle) &&
	    EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999
	    !(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
5000 5001
				if (mnt_count !=
					le16_to_cpu(sbi->s_es->s_mnt_count)) {
5002
					ext4_warning(inode->i_sb, __func__,
5003 5004 5005
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
A
Aneesh Kumar K.V 已提交
5006 5007
					mnt_count =
					  le16_to_cpu(sbi->s_es->s_mnt_count);
5008 5009 5010 5011
				}
			}
		}
	}
5012
	if (!err)
5013
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5014 5015 5016 5017
	return err;
}

/*
5018
 * ext4_dirty_inode() is called from __mark_inode_dirty()
5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030
 *
 * 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.
 */
5031
void ext4_dirty_inode(struct inode *inode)
5032
{
5033
	handle_t *current_handle = ext4_journal_current_handle();
5034 5035
	handle_t *handle;

5036 5037 5038 5039 5040
	if (!ext4_handle_valid(current_handle)) {
		ext4_mark_inode_dirty(current_handle, inode);
		return;
	}

5041
	handle = ext4_journal_start(inode, 2);
5042 5043 5044 5045 5046 5047
	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",
5048
		       __func__);
5049 5050 5051
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
5052
		ext4_mark_inode_dirty(handle, inode);
5053
	}
5054
	ext4_journal_stop(handle);
5055 5056 5057 5058 5059 5060 5061 5062
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
5063
 * ext4_reserve_inode_write, this leaves behind no bh reference and
5064 5065 5066
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
5067
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5068
{
5069
	struct ext4_iloc iloc;
5070 5071 5072

	int err = 0;
	if (handle) {
5073
		err = ext4_get_inode_loc(inode, &iloc);
5074 5075
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
5076
			err = jbd2_journal_get_write_access(handle, iloc.bh);
5077
			if (!err)
5078 5079 5080
				err = ext4_handle_dirty_metadata(handle,
								 inode,
								 iloc.bh);
5081 5082 5083
			brelse(iloc.bh);
		}
	}
5084
	ext4_std_error(inode->i_sb, err);
5085 5086 5087 5088
	return err;
}
#endif

5089
int ext4_change_inode_journal_flag(struct inode *inode, int val)
5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104
{
	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.
	 */

5105
	journal = EXT4_JOURNAL(inode);
5106 5107
	if (!journal)
		return 0;
5108
	if (is_journal_aborted(journal))
5109 5110
		return -EROFS;

5111 5112
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
5113 5114 5115 5116 5117 5118 5119 5120 5121 5122

	/*
	 * 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)
5123
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
5124
	else
5125 5126
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
5127

5128
	jbd2_journal_unlock_updates(journal);
5129 5130 5131

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

5132
	handle = ext4_journal_start(inode, 1);
5133 5134 5135
	if (IS_ERR(handle))
		return PTR_ERR(handle);

5136
	err = ext4_mark_inode_dirty(handle, inode);
5137
	ext4_handle_sync(handle);
5138 5139
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
5140 5141 5142

	return err;
}
5143 5144 5145 5146 5147 5148 5149 5150 5151 5152 5153

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;
5154
	void *fsdata;
5155 5156 5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191 5192
	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),
5193
			len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5194 5195 5196
	if (ret < 0)
		goto out_unlock;
	ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5197
			len, len, page, fsdata);
5198 5199 5200 5201 5202 5203 5204
	if (ret < 0)
		goto out_unlock;
	ret = 0;
out_unlock:
	up_read(&inode->i_alloc_sem);
	return ret;
}