inode.c 156.2 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>
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#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"
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#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;
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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
{
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	BUG_ON(EXT4_JOURNAL(inode) == NULL);
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	jbd_debug(2, "restarting handle %p\n", handle);
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	return ext4_journal_restart(handle, blocks_for_truncate(inode));
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}

/*
 * Called at the last iput() if i_nlink is zero.
 */
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void ext4_delete_inode(struct inode *inode)
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{
	handle_t *handle;
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	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);
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	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;
	}
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	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.
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	 * AKPM: I think this can be inside the above `if'.
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	 * Note that ext4_orphan_del() has to be able to cope with the
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	 * deletion of a non-existent orphan - this is because we don't
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	 * 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) {
344
		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) {
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		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;
}

374
static int __ext4_check_blockref(const char *function, struct inode *inode,
375
				 __le32 *p, unsigned int max) {
376 377

	unsigned int maxblocks = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es);
378
	__le32 *bref = p;
379
	while (bref < p+max) {
380
		if (unlikely(le32_to_cpu(*bref) >= maxblocks)) {
381 382 383
			ext4_error(inode->i_sb, function,
				   "block reference %u >= max (%u) "
				   "in inode #%lu, offset=%d",
384
				   le32_to_cpu(*bref), maxblocks,
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				   inode->i_ino, (int)(bref-p));
 			return -EIO;
 		}
		bref++;
 	}
 	return 0;
}


#define ext4_check_indirect_blockref(inode, bh)                         \
        __ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data,  \
			      EXT4_ADDR_PER_BLOCK((inode)->i_sb))

#define ext4_check_inode_blockref(inode)                                \
        __ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data,   \
			      EXT4_NDIR_BLOCKS)

402
/**
403
 *	ext4_get_branch - read the chain of indirect blocks leading to data
404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
 *	@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).
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 *
 *      Need to be called with
430
 *      down_read(&EXT4_I(inode)->i_data_sem)
431
 */
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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 */
442
	add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
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	if (!p->key)
		goto no_block;
	while (--depth) {
446 447
		bh = sb_getblk(sb, le32_to_cpu(p->key));
		if (unlikely(!bh))
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			goto failure;
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		if (!bh_uptodate_or_lock(bh)) {
			if (bh_submit_read(bh) < 0) {
				put_bh(bh);
				goto failure;
			}
			/* validate block references */
			if (ext4_check_indirect_blockref(inode, bh)) {
				put_bh(bh);
				goto failure;
			}
		}
		
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		add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
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		/* Reader: end */
		if (!p->key)
			goto no_block;
	}
	return NULL;

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

/**
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 *	ext4_find_near - find a place for allocation with sufficient locality
477 478 479
 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
480
 *	This function returns the preferred place for block allocation.
481 482 483 484 485 486 487 488 489 490 491 492 493 494
 *	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.
 */
495
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
496
{
497
	struct ext4_inode_info *ei = EXT4_I(inode);
498
	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
499
	__le32 *p;
500
	ext4_fsblk_t bg_start;
501
	ext4_fsblk_t last_block;
502
	ext4_grpblk_t colour;
503 504
	ext4_group_t block_group;
	int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
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	/* 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.
	 */
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	block_group = ei->i_block_group;
	if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
		block_group &= ~(flex_size-1);
		if (S_ISREG(inode->i_mode))
			block_group++;
	}
	bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
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	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;

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	/*
	 * If we are doing delayed allocation, we don't need take
	 * colour into account.
	 */
	if (test_opt(inode->i_sb, DELALLOC))
		return bg_start;

536 537
	if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
		colour = (current->pid % 16) *
538
			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
539 540
	else
		colour = (current->pid % 16) * ((last_block - bg_start) / 16);
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	return bg_start + colour;
}

/**
545
 *	ext4_find_goal - find a preferred place for allocation.
546 547 548 549
 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
550
 *	Normally this function find the preferred place for block allocation,
551
 *	returns it.
552
 */
A
Aneesh Kumar K.V 已提交
553
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
554
		Indirect *partial)
555 556
{
	/*
557
	 * XXX need to get goal block from mballoc's data structures
558 559
	 */

560
	return ext4_find_near(inode, partial);
561 562 563
}

/**
564
 *	ext4_blks_to_allocate: Look up the block map and count the number
565 566 567 568 569 570 571 572 573 574
 *	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.
 */
575
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
576 577
		int blocks_to_boundary)
{
578
	unsigned int count = 0;
579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601

	/*
	 * 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;
}

/**
602
 *	ext4_alloc_blocks: multiple allocate blocks needed for a branch
603 604 605 606 607 608 609 610
 *	@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
 */
611
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
612 613 614
				ext4_lblk_t iblock, ext4_fsblk_t goal,
				int indirect_blks, int blks,
				ext4_fsblk_t new_blocks[4], int *err)
615
{
616
	struct ext4_allocation_request ar;
617
	int target, i;
618
	unsigned long count = 0, blk_allocated = 0;
619
	int index = 0;
620
	ext4_fsblk_t current_block = 0;
621 622 623 624 625 626 627 628 629 630
	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)
	 */
631 632 633
	/* first we try to allocate the indirect blocks */
	target = indirect_blks;
	while (target > 0) {
634 635
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
636 637
		current_block = ext4_new_meta_blocks(handle, inode,
							goal, &count, err);
638 639 640 641 642 643 644 645 646
		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}
647 648 649 650 651 652 653 654 655
		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);
656
			break;
657
		}
658 659
	}

660 661 662 663 664
	target = blks - count ;
	blk_allocated = count;
	if (!target)
		goto allocated;
	/* Now allocate data blocks */
665 666 667 668 669 670 671 672 673 674 675
	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);

676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
	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;
		}
691
		blk_allocated += ar.len;
692 693
	}
allocated:
694
	/* total number of blocks allocated for direct blocks */
695
	ret = blk_allocated;
696 697 698
	*err = 0;
	return ret;
failed_out:
699
	for (i = 0; i < index; i++)
700
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
701 702 703 704
	return ret;
}

/**
705
 *	ext4_alloc_branch - allocate and set up a chain of blocks.
706 707 708 709 710 711 712 713 714 715
 *	@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
716
 *	the same format as ext4_get_branch() would do. We are calling it after
717 718
 *	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
719
 *	picture as after the successful ext4_get_block(), except that in one
720 721 722 723 724 725
 *	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
726
 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
727 728
 *	as described above and return 0.
 */
729
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
730 731 732
				ext4_lblk_t iblock, int indirect_blks,
				int *blks, ext4_fsblk_t goal,
				ext4_lblk_t *offsets, Indirect *branch)
733 734 735 736 737 738
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
739 740
	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
741

742
	num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
				*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");
761
		err = ext4_journal_get_create_access(handle, bh);
762 763 764 765 766 767 768 769 770 771
		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;
772
		if (n == indirect_blks) {
773 774 775 776 777 778 779 780 781 782 783 784 785
			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);

786 787
		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
		err = ext4_handle_dirty_metadata(handle, inode, bh);
788 789 790 791 792 793 794 795
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
796
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
797
		ext4_journal_forget(handle, branch[i].bh);
798
	}
799
	for (i = 0; i < indirect_blks; i++)
800
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
801

802
	ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
803 804 805 806 807

	return err;
}

/**
808
 * ext4_splice_branch - splice the allocated branch onto inode.
809 810 811
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
812
 *	ext4_alloc_branch)
813 814 815 816 817 818 819 820
 * @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.
 */
821
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
822
			ext4_lblk_t block, Indirect *where, int num, int blks)
823 824 825
{
	int i;
	int err = 0;
826
	ext4_fsblk_t current_block;
827 828 829 830 831 832 833 834

	/*
	 * 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");
835
		err = ext4_journal_get_write_access(handle, where->bh);
836 837 838 839 840 841 842 843 844 845 846 847 848 849
		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++)
850
			*(where->p + i) = cpu_to_le32(current_block++);
851 852 853 854
	}

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

K
Kalpak Shah 已提交
855
	inode->i_ctime = ext4_current_time(inode);
856
	ext4_mark_inode_dirty(handle, inode);
857 858 859 860 861 862 863 864 865

	/* 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
866
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
867 868
		 */
		jbd_debug(5, "splicing indirect only\n");
869 870
		BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
		err = ext4_handle_dirty_metadata(handle, inode, where->bh);
871 872 873 874 875 876 877 878 879 880 881 882 883
		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++) {
884
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
885
		ext4_journal_forget(handle, where[i].bh);
886 887
		ext4_free_blocks(handle, inode,
					le32_to_cpu(where[i-1].key), 1, 0);
888
	}
889
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
890 891 892 893 894

	return err;
}

/*
895 896 897 898
 * The ext4_ind_get_blocks() function handles non-extents inodes
 * (i.e., using the traditional indirect/double-indirect i_blocks
 * scheme) for ext4_get_blocks().
 *
899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
 * 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.
915
 *
916 917 918 919 920
 * The ext4_ind_get_blocks() function should be called with
 * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
 * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
 * blocks.
921
 */
922
static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
923 924
				  ext4_lblk_t iblock, unsigned int maxblocks,
				  struct buffer_head *bh_result,
925
				  int flags)
926 927
{
	int err = -EIO;
A
Aneesh Kumar K.V 已提交
928
	ext4_lblk_t offsets[4];
929 930
	Indirect chain[4];
	Indirect *partial;
931
	ext4_fsblk_t goal;
932 933 934
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
935
	struct ext4_inode_info *ei = EXT4_I(inode);
936
	int count = 0;
937
	ext4_fsblk_t first_block = 0;
938
	loff_t disksize;
939 940


A
Alex Tomas 已提交
941
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
942
	J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
A
Aneesh Kumar K.V 已提交
943 944
	depth = ext4_block_to_path(inode, iblock, offsets,
					&blocks_to_boundary);
945 946 947 948

	if (depth == 0)
		goto out;

949
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
950 951 952 953 954 955 956 957

	/* 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) {
958
			ext4_fsblk_t blk;
959 960 961 962 963 964 965 966

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

			if (blk == first_block + count)
				count++;
			else
				break;
		}
967
		goto got_it;
968 969 970
	}

	/* Next simple case - plain lookup or failed read of indirect block */
971
	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
972 973 974
		goto cleanup;

	/*
975
	 * Okay, we need to do block allocation.
976
	*/
977
	goal = ext4_find_goal(inode, iblock, partial);
978 979 980 981 982 983 984 985

	/* 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.
	 */
986
	count = ext4_blks_to_allocate(partial, indirect_blks,
987 988
					maxblocks, blocks_to_boundary);
	/*
989
	 * Block out ext4_truncate while we alter the tree
990
	 */
991 992 993
	err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
					&count, goal,
					offsets + (partial - chain), partial);
994 995

	/*
996
	 * The ext4_splice_branch call will free and forget any buffers
997 998 999 1000 1001 1002
	 * 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)
1003
		err = ext4_splice_branch(handle, inode, iblock,
1004 1005
					partial, indirect_blks, count);
	/*
1006
	 * i_disksize growing is protected by i_data_sem.  Don't forget to
1007
	 * protect it if you're about to implement concurrent
1008
	 * ext4_get_block() -bzzz
1009
	*/
1010
	if (!err && (flags & EXT4_GET_BLOCKS_EXTEND_DISKSIZE)) {
1011 1012 1013 1014 1015 1016
		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;
	}
1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
	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;
}

1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
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;
}
1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074
/*
 * 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)
{
1075 1076 1077
	if (!blocks)
		return 0;

1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
	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;

1098 1099 1100 1101 1102 1103 1104 1105 1106
	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;
	}
1107 1108 1109 1110 1111

	/* 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);
1112 1113 1114 1115 1116 1117

	/*
	 * free those over-booking quota for metadata blocks
	 */
	if (mdb_free)
		vfs_dq_release_reservation_block(inode, mdb_free);
1118 1119 1120 1121 1122 1123 1124 1125

	/*
	 * If we have done all the pending block allocations and if
	 * there aren't any writers on the inode, we can discard the
	 * inode's preallocations.
	 */
	if (!total && (atomic_read(&inode->i_writecount) == 0))
		ext4_discard_preallocations(inode);
1126 1127
}

1128
/*
1129
 * The ext4_get_blocks() function tries to look up the requested blocks,
1130
 * and returns if the blocks are already mapped.
1131 1132 1133 1134 1135 1136
 *
 * 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(),
1137
 * Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149
 * 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.
 */
1150 1151
int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
		    unsigned int max_blocks, struct buffer_head *bh,
1152
		    int flags)
1153 1154
{
	int retval;
1155 1156

	clear_buffer_mapped(bh);
1157
	clear_buffer_unwritten(bh);
1158

1159
	/*
1160 1161
	 * Try to see if we can get the block without requesting a new
	 * file system block.
1162 1163 1164 1165
	 */
	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,
1166
				bh, 0);
1167
	} else {
1168
		retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
1169
					     bh, 0);
1170
	}
1171
	up_read((&EXT4_I(inode)->i_data_sem));
1172 1173

	/* If it is only a block(s) look up */
1174
	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
1175 1176 1177 1178 1179 1180 1181 1182 1183 1184
		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))
1185 1186
		return retval;

1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198
	/*
	 * When we call get_blocks without the create flag, the
	 * BH_Unwritten flag could have gotten set if the blocks
	 * requested were part of a uninitialized extent.  We need to
	 * clear this flag now that we are committed to convert all or
	 * part of the uninitialized extent to be an initialized
	 * extent.  This is because we need to avoid the combination
	 * of BH_Unwritten and BH_Mapped flags being simultaneously
	 * set on the buffer_head.
	 */
	clear_buffer_unwritten(bh);

1199
	/*
1200 1201 1202 1203
	 * 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.
1204 1205
	 */
	down_write((&EXT4_I(inode)->i_data_sem));
1206 1207 1208 1209 1210 1211 1212

	/*
	 * 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
	 */
1213
	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1214
		EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1215 1216 1217 1218
	/*
	 * We need to check for EXT4 here because migrate
	 * could have changed the inode type in between
	 */
1219 1220
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
1221
					      bh, flags);
1222
	} else {
1223
		retval = ext4_ind_get_blocks(handle, inode, block,
1224
					     max_blocks, bh, flags);
1225 1226 1227 1228 1229 1230 1231 1232 1233 1234

		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;
		}
1235
	}
1236

1237
	if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
1238 1239 1240 1241 1242 1243 1244
		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))
1245
			ext4_da_update_reserve_space(inode, retval);
1246 1247
	}

1248
	up_write((&EXT4_I(inode)->i_data_sem));
1249 1250 1251
	return retval;
}

1252 1253 1254
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096

1255 1256
int ext4_get_block(struct inode *inode, sector_t iblock,
		   struct buffer_head *bh_result, int create)
1257
{
1258
	handle_t *handle = ext4_journal_current_handle();
J
Jan Kara 已提交
1259
	int ret = 0, started = 0;
1260
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1261
	int dio_credits;
1262

J
Jan Kara 已提交
1263 1264 1265 1266
	if (create && !handle) {
		/* Direct IO write... */
		if (max_blocks > DIO_MAX_BLOCKS)
			max_blocks = DIO_MAX_BLOCKS;
1267 1268
		dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
		handle = ext4_journal_start(inode, dio_credits);
J
Jan Kara 已提交
1269
		if (IS_ERR(handle)) {
1270
			ret = PTR_ERR(handle);
J
Jan Kara 已提交
1271
			goto out;
1272
		}
J
Jan Kara 已提交
1273
		started = 1;
1274 1275
	}

1276
	ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
1277
			      create ? EXT4_GET_BLOCKS_CREATE : 0);
J
Jan Kara 已提交
1278 1279 1280
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
1281
	}
J
Jan Kara 已提交
1282 1283 1284
	if (started)
		ext4_journal_stop(handle);
out:
1285 1286 1287 1288 1289 1290
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
1291
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1292
				ext4_lblk_t block, int create, int *errp)
1293 1294 1295
{
	struct buffer_head dummy;
	int fatal = 0, err;
1296
	int flags = EXT4_GET_BLOCKS_EXTEND_DISKSIZE;
1297 1298 1299 1300 1301 1302

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

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	buffer_trace_init(&dummy.b_history);
1303 1304 1305
	if (create)
		flags |= EXT4_GET_BLOCKS_CREATE;
	err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
1306
	/*
1307 1308
	 * ext4_get_blocks() returns number of blocks mapped. 0 in
	 * case of a HOLE.
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
	 */
	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
1325
			J_ASSERT(handle != NULL);
1326 1327 1328 1329 1330

			/*
			 * 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
1331
			 * writes use ext4_get_block instead, so it's not a
1332 1333 1334 1335
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1336
			fatal = ext4_journal_get_create_access(handle, bh);
1337
			if (!fatal && !buffer_uptodate(bh)) {
1338
				memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1339 1340 1341
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1342 1343
			BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
			err = ext4_handle_dirty_metadata(handle, inode, bh);
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359
			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;
}

1360
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1361
			       ext4_lblk_t block, int create, int *err)
1362
{
1363
	struct buffer_head *bh;
1364

1365
	bh = ext4_getblk(handle, inode, block, create, err);
1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378
	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;
}

1379 1380 1381 1382 1383 1384 1385
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))
1386 1387 1388 1389 1390 1391 1392
{
	struct buffer_head *bh;
	unsigned block_start, block_end;
	unsigned blocksize = head->b_size;
	int err, ret = 0;
	struct buffer_head *next;

1393 1394 1395
	for (bh = head, block_start = 0;
	     ret == 0 && (bh != head || !block_start);
	     block_start = block_end, bh = next)
1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413
	{
		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
1414
 * close off a transaction and start a new one between the ext4_get_block()
1415
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1416 1417
 * prepare_write() is the right place.
 *
1418 1419
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1420 1421 1422 1423
 * 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.
 *
1424
 * By accident, ext4 can be reentered when a transaction is open via
1425 1426 1427 1428 1429 1430
 * 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.
 *
1431
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1432 1433 1434 1435 1436 1437 1438 1439 1440
 * 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;
1441
	return ext4_journal_get_write_access(handle, bh);
1442 1443
}

N
Nick Piggin 已提交
1444 1445 1446
static int ext4_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
1447
{
1448
	struct inode *inode = mapping->host;
1449
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1450 1451
	handle_t *handle;
	int retries = 0;
1452
	struct page *page;
N
Nick Piggin 已提交
1453
 	pgoff_t index;
1454
	unsigned from, to;
N
Nick Piggin 已提交
1455

1456 1457 1458 1459
	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
1460
 	index = pos >> PAGE_CACHE_SHIFT;
1461 1462
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;
1463 1464

retry:
1465 1466 1467 1468
	handle = ext4_journal_start(inode, needed_blocks);
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out;
1469
	}
1470

1471 1472 1473 1474
	/* We cannot recurse into the filesystem as the transaction is already
	 * started */
	flags |= AOP_FLAG_NOFS;

1475
	page = grab_cache_page_write_begin(mapping, index, flags);
1476 1477 1478 1479 1480 1481 1482
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
	*pagep = page;

N
Nick Piggin 已提交
1483
	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1484
				ext4_get_block);
N
Nick Piggin 已提交
1485 1486

	if (!ret && ext4_should_journal_data(inode)) {
1487 1488 1489
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
N
Nick Piggin 已提交
1490 1491

	if (ret) {
1492
		unlock_page(page);
1493
		ext4_journal_stop(handle);
1494
		page_cache_release(page);
1495 1496 1497 1498 1499 1500 1501
		/*
		 * 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
1502 1503
	}

1504
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1505
		goto retry;
1506
out:
1507 1508 1509
	return ret;
}

N
Nick Piggin 已提交
1510 1511
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1512 1513 1514 1515
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1516
	return ext4_handle_dirty_metadata(handle, NULL, bh);
1517 1518 1519 1520 1521 1522
}

/*
 * 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().
 *
1523
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1524 1525
 * buffers are managed internally.
 */
N
Nick Piggin 已提交
1526 1527 1528 1529
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)
1530
{
1531
	handle_t *handle = ext4_journal_current_handle();
1532
	struct inode *inode = mapping->host;
1533 1534
	int ret = 0, ret2;

1535 1536 1537 1538
	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);
1539
	ret = ext4_jbd2_file_inode(handle, inode);
1540 1541 1542 1543

	if (ret == 0) {
		loff_t new_i_size;

N
Nick Piggin 已提交
1544
		new_i_size = pos + copied;
1545 1546 1547 1548 1549 1550 1551 1552 1553
		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);
		}

1554
		ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1555
							page, fsdata);
1556 1557 1558
		copied = ret2;
		if (ret2 < 0)
			ret = ret2;
1559
	}
1560
	ret2 = ext4_journal_stop(handle);
1561 1562
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1563 1564

	return ret ? ret : copied;
1565 1566
}

N
Nick Piggin 已提交
1567 1568 1569 1570
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)
1571
{
1572
	handle_t *handle = ext4_journal_current_handle();
1573
	struct inode *inode = mapping->host;
1574 1575 1576
	int ret = 0, ret2;
	loff_t new_i_size;

1577 1578 1579 1580
	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
1581
	new_i_size = pos + copied;
1582 1583 1584 1585 1586 1587 1588 1589
	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);
	}
1590

1591
	ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1592
							page, fsdata);
1593 1594 1595
	copied = ret2;
	if (ret2 < 0)
		ret = ret2;
1596

1597
	ret2 = ext4_journal_stop(handle);
1598 1599
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1600 1601

	return ret ? ret : copied;
1602 1603
}

N
Nick Piggin 已提交
1604 1605 1606 1607
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)
1608
{
1609
	handle_t *handle = ext4_journal_current_handle();
N
Nick Piggin 已提交
1610
	struct inode *inode = mapping->host;
1611 1612
	int ret = 0, ret2;
	int partial = 0;
N
Nick Piggin 已提交
1613
	unsigned from, to;
1614
	loff_t new_i_size;
1615

1616 1617 1618 1619
	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
1620 1621 1622 1623 1624 1625 1626 1627
	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);
	}
1628 1629

	ret = walk_page_buffers(handle, page_buffers(page), from,
N
Nick Piggin 已提交
1630
				to, &partial, write_end_fn);
1631 1632
	if (!partial)
		SetPageUptodate(page);
1633 1634
	new_i_size = pos + copied;
	if (new_i_size > inode->i_size)
N
Nick Piggin 已提交
1635
		i_size_write(inode, pos+copied);
1636
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1637 1638
	if (new_i_size > EXT4_I(inode)->i_disksize) {
		ext4_update_i_disksize(inode, new_i_size);
1639
		ret2 = ext4_mark_inode_dirty(handle, inode);
1640 1641 1642
		if (!ret)
			ret = ret2;
	}
N
Nick Piggin 已提交
1643

1644
	unlock_page(page);
1645
	ret2 = ext4_journal_stop(handle);
1646 1647
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1648 1649 1650
	page_cache_release(page);

	return ret ? ret : copied;
1651
}
1652 1653 1654

static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
{
A
Aneesh Kumar K.V 已提交
1655
	int retries = 0;
1656 1657
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	unsigned long md_needed, mdblocks, total = 0;
1658 1659 1660 1661 1662 1663

	/*
	 * 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
1664
repeat:
1665 1666 1667 1668 1669 1670 1671 1672
	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;

1673 1674 1675 1676 1677 1678 1679 1680 1681 1682
	/*
	 * 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;
	}

1683
	if (ext4_claim_free_blocks(sbi, total)) {
1684
		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
A
Aneesh Kumar K.V 已提交
1685 1686 1687 1688
		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
			yield();
			goto repeat;
		}
1689
		vfs_dq_release_reservation_block(inode, total);
1690 1691 1692 1693 1694 1695 1696 1697 1698
		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 */
}

1699
static void ext4_da_release_space(struct inode *inode, int to_free)
1700 1701 1702 1703
{
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	int total, mdb, mdb_free, release;

1704 1705 1706
	if (!to_free)
		return;		/* Nothing to release, exit */

1707
	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722

	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;
	}

1723
	/* recalculate the number of metablocks still need to be reserved */
1724
	total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1725 1726 1727 1728 1729 1730 1731 1732
	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;

1733 1734
	/* update fs dirty blocks counter for truncate case */
	percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1735 1736

	/* update per-inode reservations */
1737 1738
	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
	EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1739 1740 1741 1742

	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);
1743 1744

	vfs_dq_release_reservation_block(inode, release);
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764
}

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);
1765
	ext4_da_release_space(page->mapping->host, to_release);
1766
}
1767

1768 1769 1770 1771 1772 1773
/*
 * Delayed allocation stuff
 */

struct mpage_da_data {
	struct inode *inode;
1774 1775 1776
	sector_t b_blocknr;		/* start block number of extent */
	size_t b_size;			/* size of extent */
	unsigned long b_state;		/* state of the extent */
1777 1778
	unsigned long first_page, next_page;	/* extent of pages */
	struct writeback_control *wbc;
1779
	int io_done;
1780
	int pages_written;
1781
	int retval;
1782 1783 1784 1785
};

/*
 * mpage_da_submit_io - walks through extent of pages and try to write
1786
 * them with writepage() call back
1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798
 *
 * @mpd->inode: inode
 * @mpd->first_page: first page of the extent
 * @mpd->next_page: page after the last page of the extent
 *
 * 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)
{
1799
	long pages_skipped;
1800 1801 1802 1803 1804
	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;
1805 1806

	BUG_ON(mpd->next_page <= mpd->first_page);
1807 1808 1809
	/*
	 * We need to start from the first_page to the next_page - 1
	 * to make sure we also write the mapped dirty buffer_heads.
1810
	 * If we look at mpd->b_blocknr we would only be looking
1811 1812
	 * at the currently mapped buffer_heads.
	 */
1813 1814 1815
	index = mpd->first_page;
	end = mpd->next_page - 1;

1816
	pagevec_init(&pvec, 0);
1817
	while (index <= end) {
1818
		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1819 1820 1821 1822 1823
		if (nr_pages == 0)
			break;
		for (i = 0; i < nr_pages; i++) {
			struct page *page = pvec.pages[i];

1824 1825 1826 1827 1828 1829 1830 1831
			index = page->index;
			if (index > end)
				break;
			index++;

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

1832
			pages_skipped = mpd->wbc->pages_skipped;
1833
			err = mapping->a_ops->writepage(page, mpd->wbc);
1834 1835 1836 1837 1838
			if (!err && (pages_skipped == mpd->wbc->pages_skipped))
				/*
				 * have successfully written the page
				 * without skipping the same
				 */
1839
				mpd->pages_written++;
1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861
			/*
			 * 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
1862
 * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
1863 1864 1865 1866 1867 1868 1869 1870 1871
 */
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;
1872
	pgoff_t index, end;
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 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911
	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;
1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929

				if (buffer_delay(bh) ||
						buffer_unwritten(bh)) {

					BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);

					if (buffer_delay(bh)) {
						clear_buffer_delay(bh);
						bh->b_blocknr = pblock;
					} else {
						/*
						 * unwritten already should have
						 * blocknr assigned. Verify that
						 */
						clear_buffer_unwritten(bh);
						BUG_ON(bh->b_blocknr != pblock);
					}

1930
				} else if (buffer_mapped(bh))
1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956
					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);
}

1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
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;
}

1990 1991 1992 1993 1994 1995 1996
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",
1997
			(long long)percpu_counter_sum(&sbi->s_freeblocks_counter));
1998
	printk(KERN_EMERG "dirty_blocks=%lld\n",
1999
			(long long)percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2000
	printk(KERN_EMERG "Block reservation details\n");
2001
	printk(KERN_EMERG "i_reserved_data_blocks=%u\n",
2002
			EXT4_I(inode)->i_reserved_data_blocks);
2003
	printk(KERN_EMERG "i_reserved_meta_blocks=%u\n",
2004 2005 2006 2007
			EXT4_I(inode)->i_reserved_meta_blocks);
	return;
}

2008 2009 2010
/*
 * mpage_da_map_blocks - go through given space
 *
2011
 * @mpd - bh describing space
2012 2013 2014 2015
 *
 * The function skips space we know is already mapped to disk blocks.
 *
 */
2016
static int mpage_da_map_blocks(struct mpage_da_data *mpd)
2017
{
2018
	int err, blks;
A
Aneesh Kumar K.V 已提交
2019
	struct buffer_head new;
2020 2021 2022 2023
	sector_t next = mpd->b_blocknr;
	unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
	loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
	handle_t *handle = NULL;
2024 2025 2026 2027

	/*
	 * We consider only non-mapped and non-allocated blocks
	 */
2028
	if ((mpd->b_state  & (1 << BH_Mapped)) &&
2029 2030
		!(mpd->b_state & (1 << BH_Delay)) &&
		!(mpd->b_state & (1 << BH_Unwritten)))
2031
		return 0;
2032 2033 2034 2035 2036 2037 2038 2039 2040 2041

	/*
	 * If we didn't accumulate anything to write simply return
	 */
	if (!mpd->b_size)
		return 0;

	handle = ext4_journal_current_handle();
	BUG_ON(!handle);

2042 2043
	/*
	 * We need to make sure the BH_Delay flag is passed down to
2044 2045 2046
	 * ext4_da_get_block_write(), since it calls ext4_get_blocks()
	 * with the EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.  This flag
	 * causes ext4_get_blocks() to call
2047 2048
	 * ext4_da_update_reserve_space() if the passed buffer head
	 * has the BH_Delay flag set.  In the future, once we clean up
2049 2050
	 * the interfaces to ext4_get_blocks(), we should pass in a
	 * separate flag which requests that the delayed allocation
2051 2052
	 * statistics should be updated, instead of depending on the
	 * state information getting passed down via the map_bh's
2053 2054
	 * state bitmasks plus the magic
	 * EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.
2055 2056
	 */
	new.b_state = mpd->b_state & (1 << BH_Delay);
2057 2058 2059 2060 2061
	blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
			       &new, EXT4_GET_BLOCKS_CREATE|
			       EXT4_GET_BLOCKS_DELALLOC_RESERVE);
	if (blks < 0) {
		err = blks;
2062 2063 2064 2065
		/*
		 * If get block returns with error we simply
		 * return. Later writepage will redirty the page and
		 * writepages will find the dirty page again
2066 2067 2068
		 */
		if (err == -EAGAIN)
			return 0;
2069 2070

		if (err == -ENOSPC &&
2071
		    ext4_count_free_blocks(mpd->inode->i_sb)) {
2072 2073 2074 2075
			mpd->retval = err;
			return 0;
		}

2076
		/*
2077 2078 2079 2080 2081
		 * 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.
2082 2083 2084 2085 2086 2087
		 */
		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,
2088
				  mpd->b_size >> mpd->inode->i_blkbits, err);
2089 2090
		printk(KERN_EMERG "This should not happen.!! "
					"Data will be lost\n");
A
Aneesh Kumar K.V 已提交
2091
		if (err == -ENOSPC) {
2092
			ext4_print_free_blocks(mpd->inode);
A
Aneesh Kumar K.V 已提交
2093
		}
2094
		/* invalidate all the pages */
2095
		ext4_da_block_invalidatepages(mpd, next,
2096
				mpd->b_size >> mpd->inode->i_blkbits);
2097 2098
		return err;
	}
2099 2100 2101
	BUG_ON(blks == 0);

	new.b_size = (blks << mpd->inode->i_blkbits);
2102

2103 2104
	if (buffer_new(&new))
		__unmap_underlying_blocks(mpd->inode, &new);
2105

2106 2107 2108 2109
	/*
	 * If blocks are delayed marked, we need to
	 * put actual blocknr and drop delayed bit
	 */
2110 2111
	if ((mpd->b_state & (1 << BH_Delay)) ||
	    (mpd->b_state & (1 << BH_Unwritten)))
2112
		mpage_put_bnr_to_bhs(mpd, next, &new);
2113

2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132
	if (ext4_should_order_data(mpd->inode)) {
		err = ext4_jbd2_file_inode(handle, mpd->inode);
		if (err)
			return err;
	}

	/*
	 * Update on-disk size along with block allocation we don't
	 * use EXT4_GET_BLOCKS_EXTEND_DISKSIZE as size may change
	 * within already allocated block -bzzz
	 */
	disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
	if (disksize > i_size_read(mpd->inode))
		disksize = i_size_read(mpd->inode);
	if (disksize > EXT4_I(mpd->inode)->i_disksize) {
		ext4_update_i_disksize(mpd->inode, disksize);
		return ext4_mark_inode_dirty(handle, mpd->inode);
	}

2133
	return 0;
2134 2135
}

2136 2137
#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
		(1 << BH_Delay) | (1 << BH_Unwritten))
2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148

/*
 * 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,
2149 2150
				   sector_t logical, size_t b_size,
				   unsigned long b_state)
2151 2152
{
	sector_t next;
2153
	int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2154

2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176
	/* 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 */
		}
	}
2177 2178 2179
	/*
	 * First block in the extent
	 */
2180 2181 2182 2183
	if (mpd->b_size == 0) {
		mpd->b_blocknr = logical;
		mpd->b_size = b_size;
		mpd->b_state = b_state & BH_FLAGS;
2184 2185 2186
		return;
	}

2187
	next = mpd->b_blocknr + nrblocks;
2188 2189 2190
	/*
	 * Can we merge the block to our big extent?
	 */
2191 2192
	if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
		mpd->b_size += b_size;
2193 2194 2195
		return;
	}

2196
flush_it:
2197 2198 2199 2200
	/*
	 * We couldn't merge the block to our extent, so we
	 * need to flush current  extent and start new one
	 */
2201 2202
	if (mpage_da_map_blocks(mpd) == 0)
		mpage_da_submit_io(mpd);
2203 2204
	mpd->io_done = 1;
	return;
2205 2206
}

2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217
static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
{
	/*
	 * unmapped buffer is possible for holes.
	 * delay buffer is possible with delayed allocation.
	 * We also need to consider unwritten buffer as unmapped.
	 */
	return (!buffer_mapped(bh) || buffer_delay(bh) ||
				buffer_unwritten(bh)) && buffer_dirty(bh);
}

2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231
/*
 * __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;
2232
	struct buffer_head *bh, *head;
2233 2234
	sector_t logical;

2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245
	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;
	}
2246 2247 2248 2249 2250 2251
	/*
	 * Can we merge this page to current extent?
	 */
	if (mpd->next_page != page->index) {
		/*
		 * Nope, we can't. So, we map non-allocated blocks
2252
		 * and start IO on them using writepage()
2253 2254
		 */
		if (mpd->next_page != mpd->first_page) {
2255 2256
			if (mpage_da_map_blocks(mpd) == 0)
				mpage_da_submit_io(mpd);
2257 2258 2259 2260 2261 2262 2263
			/*
			 * 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;
2264 2265 2266 2267 2268 2269 2270 2271 2272 2273
		}

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

		/*
		 * ... and blocks
		 */
2274 2275 2276
		mpd->b_size = 0;
		mpd->b_state = 0;
		mpd->b_blocknr = 0;
2277 2278 2279 2280 2281 2282 2283
	}

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

	if (!page_has_buffers(page)) {
2284 2285
		mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
				       (1 << BH_Dirty) | (1 << BH_Uptodate));
2286 2287
		if (mpd->io_done)
			return MPAGE_DA_EXTENT_TAIL;
2288 2289 2290 2291 2292 2293 2294 2295
	} else {
		/*
		 * Page with regular buffer heads, just add all dirty ones
		 */
		head = page_buffers(page);
		bh = head;
		do {
			BUG_ON(buffer_locked(bh));
2296 2297 2298 2299 2300 2301
			/*
			 * 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
			 */
2302
			if (ext4_bh_unmapped_or_delay(NULL, bh)) {
2303 2304 2305
				mpage_add_bh_to_extent(mpd, logical,
						       bh->b_size,
						       bh->b_state);
2306 2307
				if (mpd->io_done)
					return MPAGE_DA_EXTENT_TAIL;
2308 2309 2310 2311 2312 2313 2314 2315 2316
			} 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.
				 */
2317 2318
				if (mpd->b_size == 0)
					mpd->b_state = bh->b_state & BH_FLAGS;
2319
			}
2320 2321 2322 2323 2324 2325 2326 2327
			logical++;
		} while ((bh = bh->b_this_page) != head);
	}

	return 0;
}

/*
2328 2329 2330
 * This is a special get_blocks_t callback which is used by
 * ext4_da_write_begin().  It will either return mapped block or
 * reserve space for a single block.
2331 2332 2333 2334 2335 2336 2337
 *
 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
 * We also have b_blocknr = -1 and b_bdev initialized properly
 *
 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
 * initialized properly.
2338 2339 2340 2341 2342
 */
static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
				  struct buffer_head *bh_result, int create)
{
	int ret = 0;
2343 2344 2345 2346
	sector_t invalid_block = ~((sector_t) 0xffff);

	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
		invalid_block = ~0;
2347 2348 2349 2350 2351 2352 2353 2354 2355

	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.
	 */
2356
	ret = ext4_get_blocks(NULL, inode, iblock, 1,  bh_result, 0);
2357 2358
	if ((ret == 0) && !buffer_delay(bh_result)) {
		/* the block isn't (pre)allocated yet, let's reserve space */
2359 2360 2361 2362
		/*
		 * XXX: __block_prepare_write() unmaps passed block,
		 * is it OK?
		 */
2363 2364 2365 2366 2367
		ret = ext4_da_reserve_space(inode, 1);
		if (ret)
			/* not enough space to reserve */
			return ret;

2368
		map_bh(bh_result, inode->i_sb, invalid_block);
2369 2370 2371 2372
		set_buffer_new(bh_result);
		set_buffer_delay(bh_result);
	} else if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
2373 2374 2375 2376 2377 2378 2379 2380
		if (buffer_unwritten(bh_result)) {
			/* A delayed write to unwritten bh should
			 * be marked new and mapped.  Mapped ensures
			 * that we don't do get_block multiple times
			 * when we write to the same offset and new
			 * ensures that we do proper zero out for
			 * partial write.
			 */
2381
			set_buffer_new(bh_result);
2382 2383
			set_buffer_mapped(bh_result);
		}
2384 2385 2386 2387 2388
		ret = 0;
	}

	return ret;
}
2389

2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406
/*
 * This function is used as a standard get_block_t calback function
 * when there is no desire to allocate any blocks.  It is used as a
 * callback function for block_prepare_write(), nobh_writepage(), and
 * block_write_full_page().  These functions should only try to map a
 * single block at a time.
 *
 * Since this function doesn't do block allocations even if the caller
 * requests it by passing in create=1, it is critically important that
 * any caller checks to make sure that any buffer heads are returned
 * by this function are either all already mapped or marked for
 * delayed allocation before calling nobh_writepage() or
 * block_write_full_page().  Otherwise, b_blocknr could be left
 * unitialized, and the page write functions will be taken by
 * surprise.
 */
static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
2407 2408 2409 2410 2411
				   struct buffer_head *bh_result, int create)
{
	int ret = 0;
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

2412 2413
	BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);

2414 2415 2416 2417
	/*
	 * we don't want to do block allocation in writepage
	 * so call get_block_wrap with create = 0
	 */
2418
	ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
2419
	BUG_ON(create && ret == 0);
2420 2421 2422 2423 2424
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
	}
	return ret;
2425 2426 2427
}

/*
2428 2429 2430 2431 2432
 * This function can get called via...
 *   - ext4_da_writepages after taking page lock (have journal handle)
 *   - journal_submit_inode_data_buffers (no journal handle)
 *   - shrink_page_list via pdflush (no journal handle)
 *   - grab_page_cache when doing write_begin (have journal handle)
2433
 */
2434 2435 2436 2437
static int ext4_da_writepage(struct page *page,
				struct writeback_control *wbc)
{
	int ret = 0;
2438
	loff_t size;
2439
	unsigned int len;
2440 2441 2442
	struct buffer_head *page_bufs;
	struct inode *inode = page->mapping->host;

2443 2444 2445
	trace_mark(ext4_da_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
2446 2447 2448 2449 2450
	size = i_size_read(inode);
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
2451

2452
	if (page_has_buffers(page)) {
2453
		page_bufs = page_buffers(page);
2454 2455
		if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
					ext4_bh_unmapped_or_delay)) {
2456
			/*
2457 2458
			 * We don't want to do  block allocation
			 * So redirty the page and return
2459 2460 2461
			 * 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
2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482
			 * 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,
2483
					  noalloc_get_block_write);
2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497
		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
2498 2499 2500 2501 2502
			 */
			redirty_page_for_writepage(wbc, page);
			unlock_page(page);
			return 0;
		}
2503 2504
		/* now mark the buffer_heads as dirty and uptodate */
		block_commit_write(page, 0, PAGE_CACHE_SIZE);
2505 2506 2507
	}

	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2508
		ret = nobh_writepage(page, noalloc_get_block_write, wbc);
2509
	else
2510 2511
		ret = block_write_full_page(page, noalloc_get_block_write,
					    wbc);
2512 2513 2514 2515

	return ret;
}

2516
/*
2517 2518 2519 2520 2521
 * 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.
2522
 */
2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539

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);
}
2540

2541
static int ext4_da_writepages(struct address_space *mapping,
2542
			      struct writeback_control *wbc)
2543
{
2544 2545
	pgoff_t	index;
	int range_whole = 0;
2546
	handle_t *handle = NULL;
2547
	struct mpage_da_data mpd;
2548
	struct inode *inode = mapping->host;
2549
	int no_nrwrite_index_update;
2550 2551
	int pages_written = 0;
	long pages_skipped;
2552
	int range_cyclic, cycled = 1, io_done = 0;
2553 2554
	int needed_blocks, ret = 0, nr_to_writebump = 0;
	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2555

2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569
	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);

2570 2571 2572 2573 2574
	/*
	 * 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
	 */
2575
	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2576
		return 0;
2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590

	/*
	 * 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;

2591 2592 2593 2594 2595 2596 2597 2598 2599 2600
	/*
	 * 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;
	}
2601 2602
	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
		range_whole = 1;
2603

2604 2605
	range_cyclic = wbc->range_cyclic;
	if (wbc->range_cyclic) {
2606
		index = mapping->writeback_index;
2607 2608 2609 2610 2611 2612
		if (index)
			cycled = 0;
		wbc->range_start = index << PAGE_CACHE_SHIFT;
		wbc->range_end  = LLONG_MAX;
		wbc->range_cyclic = 0;
	} else
2613
		index = wbc->range_start >> PAGE_CACHE_SHIFT;
2614

2615 2616 2617
	mpd.wbc = wbc;
	mpd.inode = mapping->host;

2618 2619 2620 2621 2622 2623 2624 2625
	/*
	 * 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;

2626
retry:
2627
	while (!ret && wbc->nr_to_write > 0) {
2628 2629 2630 2631 2632 2633 2634 2635

		/*
		 * 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));
2636
		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2637

2638 2639 2640 2641
		/* start a new transaction*/
		handle = ext4_journal_start(inode, needed_blocks);
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
2642
			printk(KERN_CRIT "%s: jbd2_start: "
2643 2644 2645
			       "%ld pages, ino %lu; err %d\n", __func__,
				wbc->nr_to_write, inode->i_ino, ret);
			dump_stack();
2646 2647
			goto out_writepages;
		}
2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679

		/*
		 * Now call __mpage_da_writepage to find the next
		 * contiguous region of logical blocks that need
		 * blocks to be allocated by ext4.  We don't actually
		 * submit the blocks for I/O here, even though
		 * write_cache_pages thinks it will, and will set the
		 * pages as clean for write before calling
		 * __mpage_da_writepage().
		 */
		mpd.b_size = 0;
		mpd.b_state = 0;
		mpd.b_blocknr = 0;
		mpd.first_page = 0;
		mpd.next_page = 0;
		mpd.io_done = 0;
		mpd.pages_written = 0;
		mpd.retval = 0;
		ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
					&mpd);
		/*
		 * If we have a contigous extent of pages and we
		 * haven't done the I/O yet, map the blocks and submit
		 * them for I/O.
		 */
		if (!mpd.io_done && mpd.next_page != mpd.first_page) {
			if (mpage_da_map_blocks(&mpd) == 0)
				mpage_da_submit_io(&mpd);
			mpd.io_done = 1;
			ret = MPAGE_DA_EXTENT_TAIL;
		}
		wbc->nr_to_write -= mpd.pages_written;
2680

2681
		ext4_journal_stop(handle);
2682

2683
		if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2684 2685 2686 2687
			/* commit the transaction which would
			 * free blocks released in the transaction
			 * and try again
			 */
2688
			jbd2_journal_force_commit_nested(sbi->s_journal);
2689 2690 2691
			wbc->pages_skipped = pages_skipped;
			ret = 0;
		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
2692 2693 2694 2695
			/*
			 * got one extent now try with
			 * rest of the pages
			 */
2696 2697
			pages_written += mpd.pages_written;
			wbc->pages_skipped = pages_skipped;
2698
			ret = 0;
2699
			io_done = 1;
2700
		} else if (wbc->nr_to_write)
2701 2702 2703 2704 2705 2706
			/*
			 * There is no more writeout needed
			 * or we requested for a noblocking writeout
			 * and we found the device congested
			 */
			break;
2707
	}
2708 2709 2710 2711 2712 2713 2714
	if (!io_done && !cycled) {
		cycled = 1;
		index = 0;
		wbc->range_start = index << PAGE_CACHE_SHIFT;
		wbc->range_end  = mapping->writeback_index - 1;
		goto retry;
	}
2715 2716 2717 2718 2719 2720 2721
	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;
2722
	wbc->range_cyclic = range_cyclic;
2723 2724 2725 2726 2727 2728
	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;
2729

2730
out_writepages:
2731 2732 2733
	if (!no_nrwrite_index_update)
		wbc->no_nrwrite_index_update = 0;
	wbc->nr_to_write -= nr_to_writebump;
2734 2735 2736 2737 2738 2739 2740 2741
	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);
2742
	return ret;
2743 2744
}

2745 2746 2747 2748 2749 2750 2751 2752 2753
#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
2754
	 * counters can get slightly wrong with percpu_counter_batch getting
2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771
	 * 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;
}

2772 2773 2774 2775
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)
{
2776
	int ret, retries = 0;
2777 2778 2779 2780 2781 2782 2783 2784 2785
	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;
2786 2787 2788 2789 2790 2791 2792

	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;
2793 2794 2795 2796 2797

	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);
2798
retry:
2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809
	/*
	 * 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;
	}
2810 2811 2812
	/* We cannot recurse into the filesystem as the transaction is already
	 * started */
	flags |= AOP_FLAG_NOFS;
2813

2814
	page = grab_cache_page_write_begin(mapping, index, flags);
2815 2816 2817 2818 2819
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
2820 2821 2822
	*pagep = page;

	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
2823
				ext4_da_get_block_prep);
2824 2825 2826 2827
	if (ret < 0) {
		unlock_page(page);
		ext4_journal_stop(handle);
		page_cache_release(page);
2828 2829 2830 2831 2832 2833 2834
		/*
		 * 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);
2835 2836
	}

2837 2838
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
		goto retry;
2839 2840 2841 2842
out:
	return ret;
}

2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857
/*
 * 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;

2858
	for (i = 0; i < idx; i++)
2859 2860
		bh = bh->b_this_page;

2861
	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2862 2863 2864 2865
		return 0;
	return 1;
}

2866 2867 2868 2869 2870 2871 2872 2873 2874
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;
2875
	unsigned long start, end;
2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888
	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();
		}
	}
2889

2890 2891 2892 2893
	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);
2894
	start = pos & (PAGE_CACHE_SIZE - 1);
2895
	end = start + copied - 1;
2896 2897 2898 2899 2900 2901 2902 2903

	/*
	 * 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;
2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914
	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);
2915

2916 2917 2918
				EXT4_I(inode)->i_disksize = new_i_size;
			}
			up_write(&EXT4_I(inode)->i_data_sem);
2919 2920 2921 2922 2923
			/* 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);
2924
		}
2925
	}
2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946
	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;

2947
	ext4_da_page_release_reservation(page, offset);
2948 2949 2950 2951 2952 2953 2954

out:
	ext4_invalidatepage(page, offset);

	return;
}

2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996
/*
 * Force all delayed allocation blocks to be allocated for a given inode.
 */
int ext4_alloc_da_blocks(struct inode *inode)
{
	if (!EXT4_I(inode)->i_reserved_data_blocks &&
	    !EXT4_I(inode)->i_reserved_meta_blocks)
		return 0;

	/*
	 * We do something simple for now.  The filemap_flush() will
	 * also start triggering a write of the data blocks, which is
	 * not strictly speaking necessary (and for users of
	 * laptop_mode, not even desirable).  However, to do otherwise
	 * would require replicating code paths in:
	 * 
	 * ext4_da_writepages() ->
	 *    write_cache_pages() ---> (via passed in callback function)
	 *        __mpage_da_writepage() -->
	 *           mpage_add_bh_to_extent()
	 *           mpage_da_map_blocks()
	 *
	 * The problem is that write_cache_pages(), located in
	 * mm/page-writeback.c, marks pages clean in preparation for
	 * doing I/O, which is not desirable if we're not planning on
	 * doing I/O at all.
	 *
	 * We could call write_cache_pages(), and then redirty all of
	 * the pages by calling redirty_page_for_writeback() but that
	 * would be ugly in the extreme.  So instead we would need to
	 * replicate parts of the code in the above functions,
	 * simplifying them becuase we wouldn't actually intend to
	 * write out the pages, but rather only collect contiguous
	 * logical block extents, call the multi-block allocator, and
	 * then update the buffer heads with the block allocations.
	 * 
	 * For now, though, we'll cheat by calling filemap_flush(),
	 * which will map the blocks, and start the I/O, but not
	 * actually wait for the I/O to complete.
	 */
	return filemap_flush(inode->i_mapping);
}
2997

2998 2999 3000 3001 3002
/*
 * 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
3003
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
3004 3005 3006 3007 3008 3009 3010 3011
 * 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.
 */
3012
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3013 3014 3015 3016 3017
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

3018 3019 3020 3021 3022 3023 3024 3025 3026 3027
	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);
	}

3028
	if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039
		/*
		 * 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.)
		 *
3040
		 * NB. EXT4_STATE_JDATA is not set on files other than
3041 3042 3043 3044 3045 3046
		 * 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.
		 */

3047 3048
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
3049 3050 3051
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
3052 3053 3054 3055 3056

		if (err)
			return 0;
	}

3057
	return generic_block_bmap(mapping, block, ext4_get_block);
3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072
}

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;
}

/*
3073 3074 3075 3076 3077 3078 3079 3080
 * 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.
3081
 *
3082
 * In all journaling modes block_write_full_page() will start the I/O.
3083 3084 3085
 *
 * Problem:
 *
3086 3087
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
3088 3089 3090
 *
 * Similar for:
 *
3091
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
3092
 *
3093
 * Same applies to ext4_get_block().  We will deadlock on various things like
3094
 * lock_journal and i_data_sem
3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124
 *
 * 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.
 *
 */
3125
static int __ext4_normal_writepage(struct page *page,
3126 3127 3128 3129 3130
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;

	if (test_opt(inode->i_sb, NOBH))
3131
		return nobh_writepage(page, noalloc_get_block_write, wbc);
3132
	else
3133 3134
		return block_write_full_page(page, noalloc_get_block_write,
					     wbc);
3135 3136
}

3137
static int ext4_normal_writepage(struct page *page,
3138 3139 3140
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
3141 3142 3143
	loff_t size = i_size_read(inode);
	loff_t len;

3144 3145 3146
	trace_mark(ext4_normal_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
3147 3148 3149 3150 3151
	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165

	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));
	}
3166 3167

	if (!ext4_journal_current_handle())
3168
		return __ext4_normal_writepage(page, wbc);
3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180

	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;
3181 3182 3183 3184
	handle_t *handle = NULL;
	int ret = 0;
	int err;

3185
	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
3186
				  noalloc_get_block_write);
3187 3188 3189 3190 3191 3192 3193 3194 3195
	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);
3196

3197
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
3198 3199
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
3200
		goto out;
3201 3202
	}

3203 3204
	ret = walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
3205

3206 3207 3208 3209
	err = walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, write_end_fn);
	if (ret == 0)
		ret = err;
3210
	err = ext4_journal_stop(handle);
3211 3212 3213
	if (!ret)
		ret = err;

3214 3215 3216 3217 3218 3219
	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:
3220
	unlock_page(page);
3221
out:
3222 3223 3224
	return ret;
}

3225
static int ext4_journalled_writepage(struct page *page,
3226 3227 3228
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
3229 3230
	loff_t size = i_size_read(inode);
	loff_t len;
3231

3232 3233 3234
	trace_mark(ext4_journalled_writepage,
		   "dev %s ino %lu page_index %lu",
		   inode->i_sb->s_id, inode->i_ino, page->index);
3235 3236 3237 3238 3239
	J_ASSERT(PageLocked(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253

	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));
	}
3254

3255
	if (ext4_journal_current_handle())
3256 3257
		goto no_write;

3258
	if (PageChecked(page)) {
3259 3260 3261 3262 3263
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
3264
		return __ext4_journalled_writepage(page, wbc);
3265 3266 3267 3268 3269 3270
	} 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.
		 */
3271 3272
		return block_write_full_page(page, noalloc_get_block_write,
					     wbc);
3273 3274 3275 3276
	}
no_write:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
3277
	return 0;
3278 3279
}

3280
static int ext4_readpage(struct file *file, struct page *page)
3281
{
3282
	return mpage_readpage(page, ext4_get_block);
3283 3284 3285
}

static int
3286
ext4_readpages(struct file *file, struct address_space *mapping,
3287 3288
		struct list_head *pages, unsigned nr_pages)
{
3289
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3290 3291
}

3292
static void ext4_invalidatepage(struct page *page, unsigned long offset)
3293
{
3294
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3295 3296 3297 3298 3299 3300 3301

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

3302 3303 3304 3305
	if (journal)
		jbd2_journal_invalidatepage(journal, page, offset);
	else
		block_invalidatepage(page, offset);
3306 3307
}

3308
static int ext4_releasepage(struct page *page, gfp_t wait)
3309
{
3310
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3311 3312 3313 3314

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
3315 3316 3317 3318
	if (journal)
		return jbd2_journal_try_to_free_buffers(journal, page, wait);
	else
		return try_to_free_buffers(page);
3319 3320 3321 3322 3323 3324 3325 3326
}

/*
 * 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
3327 3328
 * 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.
3329
 */
3330
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3331 3332 3333 3334 3335
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
3336
	struct ext4_inode_info *ei = EXT4_I(inode);
J
Jan Kara 已提交
3337
	handle_t *handle;
3338 3339 3340 3341 3342 3343 3344 3345
	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
3346 3347 3348 3349 3350 3351
			/* Credits for sb + inode write */
			handle = ext4_journal_start(inode, 2);
			if (IS_ERR(handle)) {
				ret = PTR_ERR(handle);
				goto out;
			}
3352
			ret = ext4_orphan_add(handle, inode);
J
Jan Kara 已提交
3353 3354 3355 3356
			if (ret) {
				ext4_journal_stop(handle);
				goto out;
			}
3357 3358
			orphan = 1;
			ei->i_disksize = inode->i_size;
J
Jan Kara 已提交
3359
			ext4_journal_stop(handle);
3360 3361 3362 3363 3364
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
3365
				 ext4_get_block, NULL);
3366

J
Jan Kara 已提交
3367
	if (orphan) {
3368 3369
		int err;

J
Jan Kara 已提交
3370 3371 3372 3373 3374 3375 3376 3377 3378 3379
		/* 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)
3380
			ext4_orphan_del(handle, inode);
J
Jan Kara 已提交
3381
		if (ret > 0) {
3382 3383 3384 3385 3386 3387 3388 3389
			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
3390
				 * ext4_mark_inode_dirty() to userspace.  So
3391 3392
				 * ignore it.
				 */
3393
				ext4_mark_inode_dirty(handle, inode);
3394 3395
			}
		}
3396
		err = ext4_journal_stop(handle);
3397 3398 3399 3400 3401 3402 3403 3404
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
3405
 * Pages can be marked dirty completely asynchronously from ext4's journalling
3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416
 * 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.
 */
3417
static int ext4_journalled_set_page_dirty(struct page *page)
3418 3419 3420 3421 3422
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

3423
static const struct address_space_operations ext4_ordered_aops = {
3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435
	.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,
3436 3437
};

3438
static const struct address_space_operations ext4_writeback_aops = {
3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450
	.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,
3451 3452
};

3453
static const struct address_space_operations ext4_journalled_aops = {
3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464
	.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,
3465 3466
};

3467
static const struct address_space_operations ext4_da_aops = {
3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480
	.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,
3481 3482
};

3483
void ext4_set_aops(struct inode *inode)
3484
{
3485 3486 3487 3488
	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))
3489
		inode->i_mapping->a_ops = &ext4_ordered_aops;
3490 3491 3492
	else if (ext4_should_writeback_data(inode) &&
		 test_opt(inode->i_sb, DELALLOC))
		inode->i_mapping->a_ops = &ext4_da_aops;
3493 3494
	else if (ext4_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext4_writeback_aops;
3495
	else
3496
		inode->i_mapping->a_ops = &ext4_journalled_aops;
3497 3498 3499
}

/*
3500
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3501 3502 3503 3504
 * 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.
 */
3505
int ext4_block_truncate_page(handle_t *handle,
3506 3507
		struct address_space *mapping, loff_t from)
{
3508
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3509
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
A
Aneesh Kumar K.V 已提交
3510 3511
	unsigned blocksize, length, pos;
	ext4_lblk_t iblock;
3512 3513
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
3514
	struct page *page;
3515 3516
	int err = 0;

3517 3518 3519 3520
	page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
	if (!page)
		return -EINVAL;

3521 3522 3523 3524 3525 3526 3527 3528 3529
	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) &&
3530
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
3531
		zero_user(page, offset, length);
3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555
		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");
3556
		ext4_get_block(inode, iblock, bh, 0);
3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576
		/* 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;
	}

3577
	if (ext4_should_journal_data(inode)) {
3578
		BUFFER_TRACE(bh, "get write access");
3579
		err = ext4_journal_get_write_access(handle, bh);
3580 3581 3582 3583
		if (err)
			goto unlock;
	}

3584
	zero_user(page, offset, length);
3585 3586 3587 3588

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

	err = 0;
3589
	if (ext4_should_journal_data(inode)) {
3590
		err = ext4_handle_dirty_metadata(handle, inode, bh);
3591
	} else {
3592
		if (ext4_should_order_data(inode))
3593
			err = ext4_jbd2_file_inode(handle, inode);
3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616
		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;
}

/**
3617
 *	ext4_find_shared - find the indirect blocks for partial truncation.
3618 3619
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
3620
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
3621 3622 3623
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
3624
 *	This is a helper function used by ext4_truncate().
3625 3626 3627 3628 3629 3630 3631
 *
 *	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
3632
 *	past the truncation point is possible until ext4_truncate()
3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650
 *	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).  */

3651
static Indirect *ext4_find_shared(struct inode *inode, int depth,
A
Aneesh Kumar K.V 已提交
3652
			ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
3653 3654 3655 3656 3657 3658 3659 3660
{
	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--)
		;
3661
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
3662 3663 3664 3665 3666 3667 3668 3669 3670 3671
	/* 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;
3672
	for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683
		;
	/*
	 * 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;
3684
		/* Nope, don't do this in ext4.  Must leave the tree intact */
3685 3686 3687 3688 3689 3690
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

3691
	while (partial > p) {
3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706
		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.
 */
3707 3708
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
3709 3710 3711 3712 3713
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
3714 3715
			BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
			ext4_handle_dirty_metadata(handle, inode, bh);
3716
		}
3717 3718
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
3719 3720
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
3721
			ext4_journal_get_write_access(handle, bh);
3722 3723 3724 3725 3726
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
3727
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
3728
	 * on them.  We've already detached each block from the file, so
3729
	 * bforget() in jbd2_journal_forget() should be safe.
3730
	 *
3731
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
3732 3733 3734 3735
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
A
Aneesh Kumar K.V 已提交
3736
			struct buffer_head *tbh;
3737 3738

			*p = 0;
A
Aneesh Kumar K.V 已提交
3739 3740
			tbh = sb_find_get_block(inode->i_sb, nr);
			ext4_forget(handle, 0, inode, tbh, nr);
3741 3742 3743
		}
	}

3744
	ext4_free_blocks(handle, inode, block_to_free, count, 0);
3745 3746 3747
}

/**
3748
 * ext4_free_data - free a list of data blocks
3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765
 * @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.
 */
3766
static void ext4_free_data(handle_t *handle, struct inode *inode,
3767 3768 3769
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
3770
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
3771 3772 3773 3774
	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 */
3775
	ext4_fsblk_t nr;		    /* Current block # */
3776 3777 3778 3779 3780 3781
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
3782
		err = ext4_journal_get_write_access(handle, this_bh);
3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799
		/* 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 {
3800
				ext4_clear_blocks(handle, inode, this_bh,
3801 3802 3803 3804 3805 3806 3807 3808 3809 3810
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
3811
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
3812 3813 3814
				  count, block_to_free_p, p);

	if (this_bh) {
3815
		BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
3816 3817 3818 3819 3820 3821 3822

		/*
		 * 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.
		 */
3823
		if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
3824
			ext4_handle_dirty_metadata(handle, inode, this_bh);
3825 3826 3827 3828 3829 3830
		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);
3831 3832 3833 3834
	}
}

/**
3835
 *	ext4_free_branches - free an array of branches
3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846
 *	@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.
 */
3847
static void ext4_free_branches(handle_t *handle, struct inode *inode,
3848 3849 3850
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
3851
	ext4_fsblk_t nr;
3852 3853
	__le32 *p;

3854
	if (ext4_handle_is_aborted(handle))
3855 3856 3857 3858
		return;

	if (depth--) {
		struct buffer_head *bh;
3859
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873
		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) {
3874
				ext4_error(inode->i_sb, "ext4_free_branches",
3875
					   "Read failure, inode=%lu, block=%llu",
3876 3877 3878 3879 3880 3881
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
3882
			ext4_free_branches(handle, inode, bh,
3883 3884 3885
					(__le32 *) bh->b_data,
					(__le32 *) bh->b_data + addr_per_block,
					depth);
3886 3887 3888 3889 3890

			/*
			 * 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
3891
			 * jbd2_journal_revoke().
3892 3893 3894
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
3895
			 * transaction then jbd2_journal_forget() will simply
3896
			 * brelse() it.  That means that if the underlying
3897
			 * block is reallocated in ext4_get_block(),
3898 3899 3900 3901 3902 3903 3904 3905
			 * 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.
			 */
3906
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923

			/*
			 * 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.
			 */
3924
			if (ext4_handle_is_aborted(handle))
3925 3926
				return;
			if (try_to_extend_transaction(handle, inode)) {
3927 3928
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
3929 3930
			}

3931
			ext4_free_blocks(handle, inode, nr, 1, 1);
3932 3933 3934 3935 3936 3937 3938

			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");
3939
				if (!ext4_journal_get_write_access(handle,
3940 3941 3942
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
3943 3944 3945 3946
					"call ext4_handle_dirty_metadata");
					ext4_handle_dirty_metadata(handle,
								   inode,
								   parent_bh);
3947 3948 3949 3950 3951 3952
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
3953
		ext4_free_data(handle, inode, parent_bh, first, last);
3954 3955 3956
	}
}

3957 3958 3959 3960 3961 3962 3963 3964 3965 3966 3967 3968 3969
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;
}

3970
/*
3971
 * ext4_truncate()
3972
 *
3973 3974
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990
 * 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
3991
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
3992
 * that this inode's truncate did not complete and it will again call
3993 3994
 * 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
3995
 * that's fine - as long as they are linked from the inode, the post-crash
3996
 * ext4_truncate() run will find them and release them.
3997
 */
3998
void ext4_truncate(struct inode *inode)
3999 4000
{
	handle_t *handle;
4001
	struct ext4_inode_info *ei = EXT4_I(inode);
4002
	__le32 *i_data = ei->i_data;
4003
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4004
	struct address_space *mapping = inode->i_mapping;
A
Aneesh Kumar K.V 已提交
4005
	ext4_lblk_t offsets[4];
4006 4007 4008 4009
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
A
Aneesh Kumar K.V 已提交
4010
	ext4_lblk_t last_block;
4011 4012
	unsigned blocksize = inode->i_sb->s_blocksize;

4013
	if (!ext4_can_truncate(inode))
4014 4015
		return;

4016
	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4017 4018
		ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;

A
Aneesh Kumar K.V 已提交
4019
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
4020
		ext4_ext_truncate(inode);
A
Aneesh Kumar K.V 已提交
4021 4022
		return;
	}
A
Alex Tomas 已提交
4023

4024
	handle = start_transaction(inode);
4025
	if (IS_ERR(handle))
4026 4027 4028
		return;		/* AKPM: return what? */

	last_block = (inode->i_size + blocksize-1)
4029
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
4030

4031 4032 4033
	if (inode->i_size & (blocksize - 1))
		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
			goto out_stop;
4034

4035
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047
	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.
	 */
4048
	if (ext4_orphan_add(handle, inode))
4049 4050
		goto out_stop;

4051 4052 4053 4054 4055
	/*
	 * From here we block out all ext4_get_block() callers who want to
	 * modify the block allocation tree.
	 */
	down_write(&ei->i_data_sem);
4056

4057
	ext4_discard_preallocations(inode);
4058

4059 4060 4061 4062 4063
	/*
	 * 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
4064
	 * ext4 *really* writes onto the disk inode.
4065 4066 4067 4068
	 */
	ei->i_disksize = inode->i_size;

	if (n == 1) {		/* direct blocks */
4069 4070
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
4071 4072 4073
		goto do_indirects;
	}

4074
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4075 4076 4077 4078
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
4079
			ext4_free_branches(handle, inode, NULL,
4080 4081 4082 4083 4084 4085 4086 4087 4088
					   &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");
4089
			ext4_free_branches(handle, inode, partial->bh,
4090 4091 4092 4093 4094 4095
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
4096
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4097 4098 4099 4100 4101 4102 4103 4104 4105 4106
				   (__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:
4107
		nr = i_data[EXT4_IND_BLOCK];
4108
		if (nr) {
4109 4110
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
4111
		}
4112 4113
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
4114
		if (nr) {
4115 4116
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
4117
		}
4118 4119
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
4120
		if (nr) {
4121 4122
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
4123
		}
4124
	case EXT4_TIND_BLOCK:
4125 4126 4127
		;
	}

4128
	up_write(&ei->i_data_sem);
K
Kalpak Shah 已提交
4129
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4130
	ext4_mark_inode_dirty(handle, inode);
4131 4132 4133 4134 4135 4136

	/*
	 * In a multi-transaction truncate, we only make the final transaction
	 * synchronous
	 */
	if (IS_SYNC(inode))
4137
		ext4_handle_sync(handle);
4138 4139 4140 4141 4142
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
4143
	 * ext4_delete_inode(), and we allow that function to clean up the
4144 4145 4146
	 * orphan info for us.
	 */
	if (inode->i_nlink)
4147
		ext4_orphan_del(handle, inode);
4148

4149
	ext4_journal_stop(handle);
4150 4151 4152
}

/*
4153
 * ext4_get_inode_loc returns with an extra refcount against the inode's
4154 4155 4156 4157
 * 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.
 */
4158 4159
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
4160
{
4161 4162 4163 4164 4165 4166
	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
4167
	iloc->bh = NULL;
4168 4169
	if (!ext4_valid_inum(sb, inode->i_ino))
		return -EIO;
4170

4171 4172 4173
	iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
	if (!gdp)
4174 4175
		return -EIO;

4176 4177 4178 4179 4180 4181 4182 4183 4184 4185
	/*
	 * 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);
4186
	if (!bh) {
4187 4188 4189
		ext4_error(sb, "ext4_get_inode_loc", "unable to read "
			   "inode block - inode=%lu, block=%llu",
			   inode->i_ino, block);
4190 4191 4192 4193
		return -EIO;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
4194 4195 4196 4197 4198 4199 4200 4201 4202 4203

		/*
		 * 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);

4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216
		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;
4217
			int i, start;
4218

4219
			start = inode_offset & ~(inodes_per_block - 1);
4220

4221 4222
			/* Is the inode bitmap in cache? */
			bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234
			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;
			}
4235
			for (i = start; i < start + inodes_per_block; i++) {
4236 4237
				if (i == inode_offset)
					continue;
4238
				if (ext4_test_bit(i, bitmap_bh->b_data))
4239 4240 4241
					break;
			}
			brelse(bitmap_bh);
4242
			if (i == start + inodes_per_block) {
4243 4244 4245 4246 4247 4248 4249 4250 4251
				/* 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:
4252 4253 4254 4255 4256 4257 4258 4259 4260
		/*
		 * 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);
T
Theodore Ts'o 已提交
4261
			/* s_inode_readahead_blks is always a power of 2 */
4262 4263 4264 4265 4266 4267 4268
			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))
4269
				num -= ext4_itable_unused_count(sb, gdp);
4270 4271 4272 4273 4274 4275 4276
			table += num / inodes_per_block;
			if (end > table)
				end = table;
			while (b <= end)
				sb_breadahead(sb, b++);
		}

4277 4278 4279 4280 4281 4282 4283 4284 4285 4286
		/*
		 * 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)) {
4287 4288 4289
			ext4_error(sb, __func__,
				   "unable to read inode block - inode=%lu, "
				   "block=%llu", inode->i_ino, block);
4290 4291 4292 4293 4294 4295 4296 4297 4298
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

4299
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4300 4301
{
	/* We have all inode data except xattrs in memory here. */
4302 4303
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
4304 4305
}

4306
void ext4_set_inode_flags(struct inode *inode)
4307
{
4308
	unsigned int flags = EXT4_I(inode)->i_flags;
4309 4310

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4311
	if (flags & EXT4_SYNC_FL)
4312
		inode->i_flags |= S_SYNC;
4313
	if (flags & EXT4_APPEND_FL)
4314
		inode->i_flags |= S_APPEND;
4315
	if (flags & EXT4_IMMUTABLE_FL)
4316
		inode->i_flags |= S_IMMUTABLE;
4317
	if (flags & EXT4_NOATIME_FL)
4318
		inode->i_flags |= S_NOATIME;
4319
	if (flags & EXT4_DIRSYNC_FL)
4320 4321 4322
		inode->i_flags |= S_DIRSYNC;
}

4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340
/* 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;
}
4341 4342 4343 4344
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
4345 4346
	struct inode *inode = &(ei->vfs_inode);
	struct super_block *sb = inode->i_sb;
4347 4348 4349 4350 4351 4352

	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
4353 4354 4355 4356 4357 4358
		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;
		}
4359 4360 4361 4362
	} else {
		return le32_to_cpu(raw_inode->i_blocks_lo);
	}
}
4363

4364
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4365
{
4366 4367
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
4368
	struct ext4_inode_info *ei;
4369
	struct buffer_head *bh;
4370 4371
	struct inode *inode;
	long ret;
4372 4373
	int block;

4374 4375 4376 4377 4378 4379 4380
	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
4381
#ifdef CONFIG_EXT4_FS_POSIX_ACL
4382 4383
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
4384 4385
#endif

4386 4387
	ret = __ext4_get_inode_loc(inode, &iloc, 0);
	if (ret < 0)
4388 4389
		goto bad_inode;
	bh = iloc.bh;
4390
	raw_inode = ext4_raw_inode(&iloc);
4391 4392 4393
	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);
4394
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409
		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 ||
4410
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4411
			/* this inode is deleted */
4412
			brelse(bh);
4413
			ret = -ESTALE;
4414 4415 4416 4417 4418 4419 4420 4421
			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);
4422
	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4423
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4424
	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
B
Badari Pulavarty 已提交
4425 4426
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4427
	inode->i_size = ext4_isize(raw_inode);
4428 4429 4430
	ei->i_disksize = inode->i_size;
	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
	ei->i_block_group = iloc.block_group;
4431
	ei->i_last_alloc_group = ~0;
4432 4433 4434 4435
	/*
	 * 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!
	 */
4436
	for (block = 0; block < EXT4_N_BLOCKS; block++)
4437 4438 4439
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

4440
	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4441
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4442
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4443
		    EXT4_INODE_SIZE(inode->i_sb)) {
4444
			brelse(bh);
4445
			ret = -EIO;
4446
			goto bad_inode;
4447
		}
4448 4449
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
4450 4451
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
4452 4453
		} else {
			__le32 *magic = (void *)raw_inode +
4454
					EXT4_GOOD_OLD_INODE_SIZE +
4455
					ei->i_extra_isize;
4456 4457
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
4458 4459 4460 4461
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
4462 4463 4464 4465 4466
	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);

4467 4468 4469 4470 4471 4472 4473
	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;
	}

4474
	ret = 0;
4475 4476 4477 4478 4479 4480 4481 4482 4483 4484 4485
	if (ei->i_file_acl &&
	    ((ei->i_file_acl < 
	      (le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
	       EXT4_SB(sb)->s_gdb_count)) ||
	     (ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
		ext4_error(sb, __func__,
			   "bad extended attribute block %llu in inode #%lu",
			   ei->i_file_acl, inode->i_ino);
		ret = -EIO;
		goto bad_inode;
	} else if (ei->i_flags & EXT4_EXTENTS_FL) {
4486 4487 4488 4489 4490
		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
		    (S_ISLNK(inode->i_mode) &&
		     !ext4_inode_is_fast_symlink(inode)))
			/* Validate extent which is part of inode */
			ret = ext4_ext_check_inode(inode);
4491 4492 4493 4494 4495 4496 4497 4498 4499
 	} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
		   (S_ISLNK(inode->i_mode) &&
		    !ext4_inode_is_fast_symlink(inode))) {
	 	/* Validate block references which are part of inode */
		ret = ext4_check_inode_blockref(inode);
	}
	if (ret) {
 		brelse(bh);
 		goto bad_inode;
4500 4501
	}

4502
	if (S_ISREG(inode->i_mode)) {
4503 4504 4505
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
4506
	} else if (S_ISDIR(inode->i_mode)) {
4507 4508
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
4509
	} else if (S_ISLNK(inode->i_mode)) {
4510
		if (ext4_inode_is_fast_symlink(inode)) {
4511
			inode->i_op = &ext4_fast_symlink_inode_operations;
4512 4513 4514
			nd_terminate_link(ei->i_data, inode->i_size,
				sizeof(ei->i_data) - 1);
		} else {
4515 4516
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
4517
		}
4518 4519
	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4520
		inode->i_op = &ext4_special_inode_operations;
4521 4522 4523 4524 4525 4526
		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])));
4527 4528 4529 4530 4531 4532 4533
	} else {
		brelse(bh);
		ret = -EIO;
		ext4_error(inode->i_sb, __func__, 
			   "bogus i_mode (%o) for inode=%lu",
			   inode->i_mode, inode->i_ino);
		goto bad_inode;
4534
	}
4535
	brelse(iloc.bh);
4536
	ext4_set_inode_flags(inode);
4537 4538
	unlock_new_inode(inode);
	return inode;
4539 4540

bad_inode:
4541 4542
	iget_failed(inode);
	return ERR_PTR(ret);
4543 4544
}

4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557
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
4558
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4559
		raw_inode->i_blocks_high = 0;
A
Aneesh Kumar K.V 已提交
4560
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4561 4562 4563 4564 4565 4566
		return 0;
	}
	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
		return -EFBIG;

	if (i_blocks <= 0xffffffffffffULL) {
4567 4568 4569 4570
		/*
		 * i_blocks can be represented in a 48 bit variable
		 * as multiple of 512 bytes
		 */
A
Aneesh Kumar K.V 已提交
4571
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4572
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
A
Aneesh Kumar K.V 已提交
4573
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4574
	} else {
A
Aneesh Kumar K.V 已提交
4575 4576 4577 4578 4579
		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);
4580
	}
4581
	return 0;
4582 4583
}

4584 4585 4586 4587 4588 4589 4590
/*
 * 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.
 */
4591
static int ext4_do_update_inode(handle_t *handle,
4592
				struct inode *inode,
4593
				struct ext4_iloc *iloc)
4594
{
4595 4596
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
4597 4598 4599 4600 4601
	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. */
4602 4603
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4604

4605
	ext4_get_inode_flags(ei);
4606
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4607
	if (!(test_opt(inode->i_sb, NO_UID32))) {
4608 4609 4610 4611 4612 4613
		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
 */
4614
		if (!ei->i_dtime) {
4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631
			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
4632 4633 4634 4635 4636 4637

	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);

4638 4639
	if (ext4_inode_blocks_set(handle, raw_inode, ei))
		goto out_brelse;
4640
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4641 4642
	/* clear the migrate flag in the raw_inode */
	raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
4643 4644
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
4645 4646
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
4647
	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4648 4649 4650 4651 4652 4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663
	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,
4664
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4665
			sb->s_dirt = 1;
4666 4667
			ext4_handle_sync(handle);
			err = ext4_handle_dirty_metadata(handle, inode,
4668
					EXT4_SB(sb)->s_sbh);
4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682
		}
	}
	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;
		}
4683
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
4684 4685
		raw_inode->i_block[block] = ei->i_data[block];

4686 4687 4688 4689 4690
	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);
4691
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4692 4693
	}

4694 4695
	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
	rc = ext4_handle_dirty_metadata(handle, inode, bh);
4696 4697
	if (!err)
		err = rc;
4698
	ei->i_state &= ~EXT4_STATE_NEW;
4699 4700

out_brelse:
4701
	brelse(bh);
4702
	ext4_std_error(inode->i_sb, err);
4703 4704 4705 4706
	return err;
}

/*
4707
 * ext4_write_inode()
4708 4709 4710 4711 4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723
 *
 * 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
4724
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740
 * 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.
 */
4741
int ext4_write_inode(struct inode *inode, int wait)
4742 4743 4744 4745
{
	if (current->flags & PF_MEMALLOC)
		return 0;

4746
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
4747
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4748 4749 4750 4751 4752 4753 4754
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

4755
	return ext4_force_commit(inode->i_sb);
4756 4757
}

4758 4759 4760 4761 4762 4763 4764 4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776
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;
}

4777
/*
4778
 * ext4_setattr()
4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791
 *
 * 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.)
 *
4792 4793 4794 4795 4796 4797 4798 4799
 * 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.
4800
 */
4801
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816
{
	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) */
4817 4818
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
4819 4820 4821 4822
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
4823
		error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
4824
		if (error) {
4825
			ext4_journal_stop(handle);
4826 4827 4828 4829 4830 4831 4832 4833
			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;
4834 4835
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
4836 4837
	}

4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848
	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;
			}
		}
	}

4849 4850 4851 4852
	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

4853
		handle = ext4_journal_start(inode, 3);
4854 4855 4856 4857 4858
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

4859 4860 4861
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
4862 4863
		if (!error)
			error = rc;
4864
		ext4_journal_stop(handle);
4865 4866 4867 4868 4869 4870 4871 4872 4873 4874 4875 4876 4877 4878 4879 4880

		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;
			}
		}
4881 4882 4883 4884
	}

	rc = inode_setattr(inode, attr);

4885
	/* If inode_setattr's call to ext4_truncate failed to get a
4886 4887 4888
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
4889
		ext4_orphan_del(NULL, inode);
4890 4891

	if (!rc && (ia_valid & ATTR_MODE))
4892
		rc = ext4_acl_chmod(inode);
4893 4894

err_out:
4895
	ext4_std_error(inode->i_sb, error);
4896 4897 4898 4899 4900
	if (!error)
		error = rc;
	return error;
}

4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926
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;
}
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 4953 4954 4955
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))
4956 4957
		return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
	return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4958
}
4959

4960
/*
4961 4962 4963
 * 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
4964
 *
4965 4966 4967
 * 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.
4968
 *
4969 4970 4971 4972
 * Also account for superblock, inode, quota and xattr blocks
 */
int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
{
4973 4974
	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
	int gdpblocks;
4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000
	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;
5001 5002
	if (groups > ngroups)
		groups = ngroups;
5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016
	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
5017 5018
 * the modification of a single pages into a single transaction,
 * which may include multiple chunks of block allocations.
5019
 *
5020
 * This could be called via ext4_write_begin()
5021
 *
5022
 * We need to consider the worse case, when
5023
 * one new block per extent.
5024
 */
A
Alex Tomas 已提交
5025
int ext4_writepage_trans_blocks(struct inode *inode)
5026
{
5027
	int bpp = ext4_journal_blocks_per_page(inode);
5028 5029
	int ret;

5030
	ret = ext4_meta_trans_blocks(inode, bpp, 0);
A
Alex Tomas 已提交
5031

5032
	/* Account for data blocks for journalled mode */
5033
	if (ext4_should_journal_data(inode))
5034
		ret += bpp;
5035 5036
	return ret;
}
5037 5038 5039 5040 5041

/*
 * Calculate the journal credits for a chunk of data modification.
 *
 * This is called from DIO, fallocate or whoever calling
5042
 * ext4_get_blocks() to map/allocate a chunk of contigous disk blocks.
5043 5044 5045 5046 5047 5048 5049 5050 5051
 *
 * 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);
}

5052
/*
5053
 * The caller must have previously called ext4_reserve_inode_write().
5054 5055
 * Give this, we know that the caller already has write access to iloc->bh.
 */
5056 5057
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
5058 5059 5060
{
	int err = 0;

5061 5062 5063
	if (test_opt(inode->i_sb, I_VERSION))
		inode_inc_iversion(inode);

5064 5065 5066
	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

5067
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5068
	err = ext4_do_update_inode(handle, inode, iloc);
5069 5070 5071 5072 5073 5074 5075 5076 5077 5078
	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
5079 5080
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
5081
{
5082 5083 5084 5085 5086 5087 5088 5089 5090
	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;
5091 5092
		}
	}
5093
	ext4_std_error(inode->i_sb, err);
5094 5095 5096
	return err;
}

5097 5098 5099 5100
/*
 * 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
5101 5102 5103 5104
static int ext4_expand_extra_isize(struct inode *inode,
				   unsigned int new_extra_isize,
				   struct ext4_iloc iloc,
				   handle_t *handle)
5105 5106 5107 5108 5109 5110 5111 5112 5113 5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131
{
	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);
}

5132 5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149 5150 5151 5152
/*
 * 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.
 */
5153
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5154
{
5155
	struct ext4_iloc iloc;
5156 5157 5158
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
5159 5160

	might_sleep();
5161
	err = ext4_reserve_inode_write(handle, inode, &iloc);
5162 5163
	if (ext4_handle_valid(handle) &&
	    EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5164 5165 5166 5167 5168 5169 5170 5171 5172 5173 5174 5175 5176 5177 5178
	    !(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
5179 5180
				if (mnt_count !=
					le16_to_cpu(sbi->s_es->s_mnt_count)) {
5181
					ext4_warning(inode->i_sb, __func__,
5182 5183 5184
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
A
Aneesh Kumar K.V 已提交
5185 5186
					mnt_count =
					  le16_to_cpu(sbi->s_es->s_mnt_count);
5187 5188 5189 5190
				}
			}
		}
	}
5191
	if (!err)
5192
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5193 5194 5195 5196
	return err;
}

/*
5197
 * ext4_dirty_inode() is called from __mark_inode_dirty()
5198 5199 5200 5201 5202
 *
 * 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.
 *
5203
 * Also, vfs_dq_alloc_block() will always dirty the inode when blocks
5204 5205 5206 5207 5208 5209
 * 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.
 */
5210
void ext4_dirty_inode(struct inode *inode)
5211
{
5212
	handle_t *current_handle = ext4_journal_current_handle();
5213 5214
	handle_t *handle;

5215 5216 5217 5218 5219
	if (!ext4_handle_valid(current_handle)) {
		ext4_mark_inode_dirty(current_handle, inode);
		return;
	}

5220
	handle = ext4_journal_start(inode, 2);
5221 5222 5223 5224 5225 5226
	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",
5227
		       __func__);
5228 5229 5230
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
5231
		ext4_mark_inode_dirty(handle, inode);
5232
	}
5233
	ext4_journal_stop(handle);
5234 5235 5236 5237 5238 5239 5240 5241
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
5242
 * ext4_reserve_inode_write, this leaves behind no bh reference and
5243 5244 5245
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
5246
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5247
{
5248
	struct ext4_iloc iloc;
5249 5250 5251

	int err = 0;
	if (handle) {
5252
		err = ext4_get_inode_loc(inode, &iloc);
5253 5254
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
5255
			err = jbd2_journal_get_write_access(handle, iloc.bh);
5256
			if (!err)
5257 5258 5259
				err = ext4_handle_dirty_metadata(handle,
								 inode,
								 iloc.bh);
5260 5261 5262
			brelse(iloc.bh);
		}
	}
5263
	ext4_std_error(inode->i_sb, err);
5264 5265 5266 5267
	return err;
}
#endif

5268
int ext4_change_inode_journal_flag(struct inode *inode, int val)
5269 5270 5271 5272 5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283
{
	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.
	 */

5284
	journal = EXT4_JOURNAL(inode);
5285 5286
	if (!journal)
		return 0;
5287
	if (is_journal_aborted(journal))
5288 5289
		return -EROFS;

5290 5291
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
5292 5293 5294 5295 5296 5297 5298 5299 5300 5301

	/*
	 * 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)
5302
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
5303
	else
5304 5305
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
5306

5307
	jbd2_journal_unlock_updates(journal);
5308 5309 5310

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

5311
	handle = ext4_journal_start(inode, 1);
5312 5313 5314
	if (IS_ERR(handle))
		return PTR_ERR(handle);

5315
	err = ext4_mark_inode_dirty(handle, inode);
5316
	ext4_handle_sync(handle);
5317 5318
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
5319 5320 5321

	return err;
}
5322 5323 5324 5325 5326 5327

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

5328
int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5329
{
5330
	struct page *page = vmf->page;
5331 5332 5333
	loff_t size;
	unsigned long len;
	int ret = -EINVAL;
5334
	void *fsdata;
5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364 5365 5366 5367 5368 5369 5370 5371 5372
	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),
5373
			len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5374 5375 5376
	if (ret < 0)
		goto out_unlock;
	ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5377
			len, len, page, fsdata);
5378 5379 5380 5381
	if (ret < 0)
		goto out_unlock;
	ret = 0;
out_unlock:
5382 5383
	if (ret)
		ret = VM_FAULT_SIGBUS;
5384 5385 5386
	up_read(&inode->i_alloc_sem);
	return ret;
}