inode.c 99.8 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/ext4_jbd2.h>
#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>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include "xattr.h"
#include "acl.h"

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

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

/*
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 * The ext4 forget function must perform a revoke if we are freeing data
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 * which has been journaled.  Metadata (eg. indirect blocks) must be
 * revoked in all cases.
 *
 * "bh" may be NULL: a metadata block may have been freed from memory
 * but there may still be a record of it in the journal, and that record
 * still needs to be revoked.
 */
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int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
			struct buffer_head *bh, ext4_fsblk_t blocknr)
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{
	int err;

	might_sleep();

	BUFFER_TRACE(bh, "enter");

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

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

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	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
	    (!is_metadata && !ext4_should_journal_data(inode))) {
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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, __FUNCTION__,
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			   "error %d when attempting revoke", err);
	BUFFER_TRACE(bh, "exit");
	return err;
}

/*
 * Work out how many blocks we need to proceed with the next chunk of a
 * truncate transaction.
 */
static unsigned long blocks_for_truncate(struct inode *inode)
{
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	ext4_lblk_t needed;
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	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);

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

	/* But we need to bound the transaction so we don't overflow the
	 * journal. */
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	if (needed > EXT4_MAX_TRANS_DATA)
		needed = EXT4_MAX_TRANS_DATA;
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	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
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}

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

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

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	ext4_std_error(inode->i_sb, PTR_ERR(result));
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	return result;
}

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

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

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

	truncate_inode_pages(&inode->i_data, 0);

	if (is_bad_inode(inode))
		goto no_delete;

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

	if (IS_SYNC(inode))
		handle->h_sync = 1;
	inode->i_size = 0;
	if (inode->i_blocks)
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		ext4_truncate(inode);
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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)
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{
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	int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
	int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
	const long direct_blocks = EXT4_NDIR_BLOCKS,
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		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;
	int final = 0;

	if (i_block < 0) {
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		ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0");
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	} else if (i_block < direct_blocks) {
		offsets[n++] = i_block;
		final = direct_blocks;
	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
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		offsets[n++] = EXT4_IND_BLOCK;
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		offsets[n++] = i_block;
		final = ptrs;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
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		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",
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				"block %lu > max",
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				i_block + direct_blocks +
				indirect_blocks + double_blocks);
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	}
	if (boundary)
		*boundary = final - 1 - (i_block & (ptrs - 1));
	return n;
}

/**
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 *	ext4_get_branch - read the chain of indirect blocks leading to data
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 *	@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
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 *      down_read(&EXT4_I(inode)->i_data_sem)
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 */
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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 */
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	add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets);
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	if (!p->key)
		goto no_block;
	while (--depth) {
		bh = sb_bread(sb, le32_to_cpu(p->key));
		if (!bh)
			goto failure;
		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
		/* 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
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 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
 *	This function returns the prefered place for block allocation.
 *	It is used when heuristic for sequential allocation fails.
 *	Rules are:
 *	  + if there is a block to the left of our position - allocate near it.
 *	  + if pointer will live in indirect block - allocate near that block.
 *	  + if pointer will live in inode - allocate in the same
 *	    cylinder group.
 *
 * In the latter case we colour the starting block by the callers PID to
 * prevent it from clashing with concurrent allocations for a different inode
 * in the same block group.   The PID is used here so that functionally related
 * files will be close-by on-disk.
 *
 *	Caller must make sure that @ind is valid and will stay that way.
 */
400
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
401
{
402
	struct ext4_inode_info *ei = EXT4_I(inode);
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	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
	__le32 *p;
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	ext4_fsblk_t bg_start;
	ext4_grpblk_t colour;
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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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	bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
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	colour = (current->pid % 16) *
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			(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
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	return bg_start + colour;
}

/**
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 *	ext4_find_goal - find a prefered place for allocation.
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 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
 *	Normally this function find the prefered place for block allocation,
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 *	returns it.
436
 */
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static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
438
		Indirect *partial)
439
{
440
	struct ext4_block_alloc_info *block_i;
441

442
	block_i =  EXT4_I(inode)->i_block_alloc_info;
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	/*
	 * try the heuristic for sequential allocation,
	 * failing that at least try to get decent locality.
	 */
	if (block_i && (block == block_i->last_alloc_logical_block + 1)
		&& (block_i->last_alloc_physical_block != 0)) {
		return block_i->last_alloc_physical_block + 1;
	}

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	return ext4_find_near(inode, partial);
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}

/**
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 *	ext4_blks_to_allocate: Look up the block map and count the number
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 *	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.
 */
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static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
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		int blocks_to_boundary)
{
	unsigned long count = 0;

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

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

/**
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 *	ext4_alloc_blocks: multiple allocate blocks needed for a branch
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 *	@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
 */
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static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
			ext4_fsblk_t goal, int indirect_blks, int blks,
			ext4_fsblk_t new_blocks[4], int *err)
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{
	int target, i;
	unsigned long count = 0;
	int index = 0;
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	ext4_fsblk_t current_block = 0;
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	int ret = 0;

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

	while (1) {
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
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		current_block = ext4_new_blocks(handle,inode,goal,&count,err);
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		if (*err)
			goto failed_out;

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

		if (count > 0)
			break;
	}

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

	/* total number of blocks allocated for direct blocks */
	ret = count;
	*err = 0;
	return ret;
failed_out:
	for (i = 0; i <index; i++)
551
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
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	return ret;
}

/**
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 *	ext4_alloc_branch - allocate and set up a chain of blocks.
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 *	@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
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 *	the same format as ext4_get_branch() would do. We are calling it after
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 *	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
570
 *	picture as after the successful ext4_get_block(), except that in one
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 *	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
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 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
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 *	as described above and return 0.
 */
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static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
			int indirect_blks, int *blks, ext4_fsblk_t goal,
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			ext4_lblk_t *offsets, Indirect *branch)
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{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
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	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
591

592
	num = ext4_alloc_blocks(handle, inode, goal, indirect_blks,
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				*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");
611
		err = ext4_journal_get_create_access(handle, bh);
612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635
		if (err) {
			unlock_buffer(bh);
			brelse(bh);
			goto failed;
		}

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

636 637
		BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, bh);
638 639 640 641 642 643 644 645
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
646
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
647
		ext4_journal_forget(handle, branch[i].bh);
648 649
	}
	for (i = 0; i <indirect_blks; i++)
650
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
651

652
	ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
653 654 655 656 657

	return err;
}

/**
658
 * ext4_splice_branch - splice the allocated branch onto inode.
659 660 661
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
662
 *	ext4_alloc_branch)
663 664 665 666 667 668 669 670
 * @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.
 */
671
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
672
			ext4_lblk_t block, Indirect *where, int num, int blks)
673 674 675
{
	int i;
	int err = 0;
676 677
	struct ext4_block_alloc_info *block_i;
	ext4_fsblk_t current_block;
678

679
	block_i = EXT4_I(inode)->i_block_alloc_info;
680 681 682 683 684 685 686
	/*
	 * 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");
687
		err = ext4_journal_get_write_access(handle, where->bh);
688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
		if (err)
			goto err_out;
	}
	/* That's it */

	*where->p = where->key;

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

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

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

K
Kalpak Shah 已提交
718
	inode->i_ctime = ext4_current_time(inode);
719
	ext4_mark_inode_dirty(handle, inode);
720 721 722 723 724 725 726 727 728

	/* 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
729
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
730 731
		 */
		jbd_debug(5, "splicing indirect only\n");
732 733
		BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, where->bh);
734 735 736 737 738 739 740 741 742 743 744 745 746
		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++) {
747
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
748
		ext4_journal_forget(handle, where[i].bh);
749 750
		ext4_free_blocks(handle, inode,
					le32_to_cpu(where[i-1].key), 1, 0);
751
	}
752
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774

	return err;
}

/*
 * Allocation strategy is simple: if we have to allocate something, we will
 * have to go the whole way to leaf. So let's do it before attaching anything
 * to tree, set linkage between the newborn blocks, write them if sync is
 * required, recheck the path, free and repeat if check fails, otherwise
 * set the last missing link (that will protect us from any truncate-generated
 * removals - all blocks on the path are immune now) and possibly force the
 * write on the parent block.
 * That has a nice additional property: no special recovery from the failed
 * allocations is needed - we simply release blocks and do not touch anything
 * reachable from inode.
 *
 * `handle' can be NULL if create == 0.
 *
 * The BKL may not be held on entry here.  Be sure to take it early.
 * return > 0, # of blocks mapped or allocated.
 * return = 0, if plain lookup failed.
 * return < 0, error case.
775 776 777
 *
 *
 * Need to be called with
778 779
 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
780
 */
781
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
782
		ext4_lblk_t iblock, unsigned long maxblocks,
783 784 785 786
		struct buffer_head *bh_result,
		int create, int extend_disksize)
{
	int err = -EIO;
A
Aneesh Kumar K.V 已提交
787
	ext4_lblk_t offsets[4];
788 789
	Indirect chain[4];
	Indirect *partial;
790
	ext4_fsblk_t goal;
791 792 793
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
794
	struct ext4_inode_info *ei = EXT4_I(inode);
795
	int count = 0;
796
	ext4_fsblk_t first_block = 0;
797 798


A
Alex Tomas 已提交
799
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
800
	J_ASSERT(handle != NULL || create == 0);
A
Aneesh Kumar K.V 已提交
801 802
	depth = ext4_block_to_path(inode, iblock, offsets,
					&blocks_to_boundary);
803 804 805 806

	if (depth == 0)
		goto out;

807
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
808 809 810 811 812 813 814 815

	/* 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) {
816
			ext4_fsblk_t blk;
817 818 819 820 821 822 823 824

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

			if (blk == first_block + count)
				count++;
			else
				break;
		}
825
		goto got_it;
826 827 828 829 830 831 832 833 834 835 836
	}

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

	/*
	 * Okay, we need to do block allocation.  Lazily initialize the block
	 * allocation info here if necessary
	*/
	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
837
		ext4_init_block_alloc_info(inode);
838

839
	goal = ext4_find_goal(inode, iblock, partial);
840 841 842 843 844 845 846 847

	/* 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.
	 */
848
	count = ext4_blks_to_allocate(partial, indirect_blks,
849 850
					maxblocks, blocks_to_boundary);
	/*
851
	 * Block out ext4_truncate while we alter the tree
852
	 */
853
	err = ext4_alloc_branch(handle, inode, indirect_blks, &count, goal,
854 855 856
				offsets + (partial - chain), partial);

	/*
857
	 * The ext4_splice_branch call will free and forget any buffers
858 859 860 861 862 863
	 * 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)
864
		err = ext4_splice_branch(handle, inode, iblock,
865 866
					partial, indirect_blks, count);
	/*
867
	 * i_disksize growing is protected by i_data_sem.  Don't forget to
868
	 * protect it if you're about to implement concurrent
869
	 * ext4_get_block() -bzzz
870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894
	*/
	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
		ei->i_disksize = inode->i_size;
	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;
}

895
#define DIO_CREDITS (EXT4_RESERVE_TRANS_BLOCKS + 32)
896

897 898 899 900 901
int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
			unsigned long max_blocks, struct buffer_head *bh,
			int create, int extend_disksize)
{
	int retval;
902 903 904 905 906 907 908 909
	/*
	 * Try to see if we can get  the block without requesting
	 * for new file system block.
	 */
	down_read((&EXT4_I(inode)->i_data_sem));
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
				bh, 0, 0);
910
	} else {
911 912
		retval = ext4_get_blocks_handle(handle,
				inode, block, max_blocks, bh, 0, 0);
913
	}
914 915 916 917 918 919 920 921 922 923 924 925 926
	up_read((&EXT4_I(inode)->i_data_sem));
	if (!create || (retval > 0))
		return retval;

	/*
	 * We need to allocate new blocks which will result
	 * in i_data update
	 */
	down_write((&EXT4_I(inode)->i_data_sem));
	/*
	 * We need to check for EXT4 here because migrate
	 * could have changed the inode type in between
	 */
927 928 929 930 931 932 933
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
				bh, create, extend_disksize);
	} else {
		retval = ext4_get_blocks_handle(handle, inode, block,
				max_blocks, bh, create, extend_disksize);
	}
934
	up_write((&EXT4_I(inode)->i_data_sem));
935 936 937
	return retval;
}

938
static int ext4_get_block(struct inode *inode, sector_t iblock,
939 940
			struct buffer_head *bh_result, int create)
{
941
	handle_t *handle = ext4_journal_current_handle();
942 943 944 945 946 947 948 949 950 951 952 953 954 955
	int ret = 0;
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

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

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

	if (handle->h_transaction->t_state == T_LOCKED) {
		/*
		 * Huge direct-io writes can hold off commits for long
		 * periods of time.  Let this commit run.
		 */
956 957
		ext4_journal_stop(handle);
		handle = ext4_journal_start(inode, DIO_CREDITS);
958 959 960 961 962
		if (IS_ERR(handle))
			ret = PTR_ERR(handle);
		goto get_block;
	}

963
	if (handle->h_buffer_credits <= EXT4_RESERVE_TRANS_BLOCKS) {
964 965 966
		/*
		 * Getting low on buffer credits...
		 */
967
		ret = ext4_journal_extend(handle, DIO_CREDITS);
968 969 970 971
		if (ret > 0) {
			/*
			 * Couldn't extend the transaction.  Start a new one.
			 */
972
			ret = ext4_journal_restart(handle, DIO_CREDITS);
973 974 975 976 977
		}
	}

get_block:
	if (ret == 0) {
A
Alex Tomas 已提交
978
		ret = ext4_get_blocks_wrap(handle, inode, iblock,
979 980 981 982 983 984 985 986 987 988 989 990
					max_blocks, bh_result, create, 0);
		if (ret > 0) {
			bh_result->b_size = (ret << inode->i_blkbits);
			ret = 0;
		}
	}
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
991
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
992
				ext4_lblk_t block, int create, int *errp)
993 994 995 996 997 998 999 1000 1001
{
	struct buffer_head dummy;
	int fatal = 0, err;

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

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	buffer_trace_init(&dummy.b_history);
A
Alex Tomas 已提交
1002
	err = ext4_get_blocks_wrap(handle, inode, block, 1,
1003 1004
					&dummy, create, 1);
	/*
1005
	 * ext4_get_blocks_handle() returns number of blocks
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	 * mapped. 0 in case of a HOLE.
	 */
	if (err > 0) {
		if (err > 1)
			WARN_ON(1);
		err = 0;
	}
	*errp = err;
	if (!err && buffer_mapped(&dummy)) {
		struct buffer_head *bh;
		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
		if (!bh) {
			*errp = -EIO;
			goto err;
		}
		if (buffer_new(&dummy)) {
			J_ASSERT(create != 0);
A
Aneesh Kumar K.V 已提交
1023
			J_ASSERT(handle != NULL);
1024 1025 1026 1027 1028

			/*
			 * 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
1029
			 * writes use ext4_get_block instead, so it's not a
1030 1031 1032 1033
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1034
			fatal = ext4_journal_get_create_access(handle, bh);
1035 1036 1037 1038 1039
			if (!fatal && !buffer_uptodate(bh)) {
				memset(bh->b_data,0,inode->i_sb->s_blocksize);
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1040 1041
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			err = ext4_journal_dirty_metadata(handle, bh);
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
			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;
}

1058
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1059
			       ext4_lblk_t block, int create, int *err)
1060 1061 1062
{
	struct buffer_head * bh;

1063
	bh = ext4_getblk(handle, inode, block, create, err);
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
	if (!bh)
		return bh;
	if (buffer_uptodate(bh))
		return bh;
	ll_rw_block(READ_META, 1, &bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;
	put_bh(bh);
	*err = -EIO;
	return NULL;
}

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

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

/*
 * To preserve ordering, it is essential that the hole instantiation and
 * the data write be encapsulated in a single transaction.  We cannot
1112
 * close off a transaction and start a new one between the ext4_get_block()
1113
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1114 1115
 * prepare_write() is the right place.
 *
1116 1117
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1118 1119 1120 1121
 * 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.
 *
1122
 * By accident, ext4 can be reentered when a transaction is open via
1123 1124 1125 1126 1127 1128
 * 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.
 *
1129
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1130 1131 1132 1133 1134 1135 1136 1137 1138
 * 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;
1139
	return ext4_journal_get_write_access(handle, bh);
1140 1141
}

N
Nick Piggin 已提交
1142 1143 1144
static int ext4_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
1145
{
N
Nick Piggin 已提交
1146
 	struct inode *inode = mapping->host;
1147
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1148 1149
	handle_t *handle;
	int retries = 0;
N
Nick Piggin 已提交
1150 1151 1152 1153 1154 1155 1156
 	struct page *page;
 	pgoff_t index;
 	unsigned from, to;

 	index = pos >> PAGE_CACHE_SHIFT;
 	from = pos & (PAGE_CACHE_SIZE - 1);
 	to = from + len;
1157 1158

retry:
N
Nick Piggin 已提交
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169
 	page = __grab_cache_page(mapping, index);
 	if (!page)
 		return -ENOMEM;
 	*pagep = page;

  	handle = ext4_journal_start(inode, needed_blocks);
  	if (IS_ERR(handle)) {
 		unlock_page(page);
 		page_cache_release(page);
  		ret = PTR_ERR(handle);
  		goto out;
1170
	}
1171

N
Nick Piggin 已提交
1172 1173 1174 1175
	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
							ext4_get_block);

	if (!ret && ext4_should_journal_data(inode)) {
1176 1177 1178
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
N
Nick Piggin 已提交
1179 1180

	if (ret) {
1181
		ext4_journal_stop(handle);
N
Nick Piggin 已提交
1182 1183 1184 1185
 		unlock_page(page);
 		page_cache_release(page);
	}

1186
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1187
		goto retry;
1188
out:
1189 1190 1191
	return ret;
}

1192
int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1193
{
1194
	int err = jbd2_journal_dirty_data(handle, bh);
1195
	if (err)
1196
		ext4_journal_abort_handle(__FUNCTION__, __FUNCTION__,
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1197
						bh, handle, err);
1198 1199 1200
	return err;
}

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1201 1202
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1203 1204 1205 1206
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1207
	return ext4_journal_dirty_metadata(handle, bh);
1208 1209
}

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1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232
/*
 * Generic write_end handler for ordered and writeback ext4 journal modes.
 * We can't use generic_write_end, because that unlocks the page and we need to
 * unlock the page after ext4_journal_stop, but ext4_journal_stop must run
 * after block_write_end.
 */
static int ext4_generic_write_end(struct file *file,
				struct address_space *mapping,
				loff_t pos, unsigned len, unsigned copied,
				struct page *page, void *fsdata)
{
	struct inode *inode = file->f_mapping->host;

	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);

	if (pos+copied > inode->i_size) {
		i_size_write(inode, pos+copied);
		mark_inode_dirty(inode);
	}

	return copied;
}

1233 1234 1235 1236
/*
 * 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().
 *
1237
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1238 1239
 * buffers are managed internally.
 */
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1240 1241 1242 1243
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)
1244
{
1245
	handle_t *handle = ext4_journal_current_handle();
N
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1246 1247
	struct inode *inode = file->f_mapping->host;
	unsigned from, to;
1248 1249
	int ret = 0, ret2;

N
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1250 1251 1252
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;

1253
	ret = walk_page_buffers(handle, page_buffers(page),
1254
		from, to, NULL, ext4_journal_dirty_data);
1255 1256 1257

	if (ret == 0) {
		/*
N
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1258
		 * generic_write_end() will run mark_inode_dirty() if i_size
1259 1260 1261 1262 1263
		 * changes.  So let's piggyback the i_disksize mark_inode_dirty
		 * into that.
		 */
		loff_t new_i_size;

N
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1264
		new_i_size = pos + copied;
1265 1266
		if (new_i_size > EXT4_I(inode)->i_disksize)
			EXT4_I(inode)->i_disksize = new_i_size;
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1267 1268 1269 1270
		copied = ext4_generic_write_end(file, mapping, pos, len, copied,
							page, fsdata);
		if (copied < 0)
			ret = copied;
1271
	}
1272
	ret2 = ext4_journal_stop(handle);
1273 1274
	if (!ret)
		ret = ret2;
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1275 1276 1277 1278
	unlock_page(page);
	page_cache_release(page);

	return ret ? ret : copied;
1279 1280
}

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1281 1282 1283 1284
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)
1285
{
1286
	handle_t *handle = ext4_journal_current_handle();
N
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1287
	struct inode *inode = file->f_mapping->host;
1288 1289 1290
	int ret = 0, ret2;
	loff_t new_i_size;

N
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1291
	new_i_size = pos + copied;
1292 1293
	if (new_i_size > EXT4_I(inode)->i_disksize)
		EXT4_I(inode)->i_disksize = new_i_size;
1294

N
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1295 1296 1297 1298
	copied = ext4_generic_write_end(file, mapping, pos, len, copied,
							page, fsdata);
	if (copied < 0)
		ret = copied;
1299

1300
	ret2 = ext4_journal_stop(handle);
1301 1302
	if (!ret)
		ret = ret2;
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1303 1304 1305 1306
	unlock_page(page);
	page_cache_release(page);

	return ret ? ret : copied;
1307 1308
}

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1309 1310 1311 1312
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)
1313
{
1314
	handle_t *handle = ext4_journal_current_handle();
N
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1315
	struct inode *inode = mapping->host;
1316 1317
	int ret = 0, ret2;
	int partial = 0;
N
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1318
	unsigned from, to;
1319

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1320 1321 1322 1323 1324 1325 1326 1327
	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);
	}
1328 1329

	ret = walk_page_buffers(handle, page_buffers(page), from,
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1330
				to, &partial, write_end_fn);
1331 1332
	if (!partial)
		SetPageUptodate(page);
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1333 1334
	if (pos+copied > inode->i_size)
		i_size_write(inode, pos+copied);
1335 1336 1337 1338
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
	if (inode->i_size > EXT4_I(inode)->i_disksize) {
		EXT4_I(inode)->i_disksize = inode->i_size;
		ret2 = ext4_mark_inode_dirty(handle, inode);
1339 1340 1341
		if (!ret)
			ret = ret2;
	}
N
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1342

1343
	ret2 = ext4_journal_stop(handle);
1344 1345
	if (!ret)
		ret = ret2;
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1346 1347 1348 1349
	unlock_page(page);
	page_cache_release(page);

	return ret ? ret : copied;
1350 1351 1352 1353 1354 1355 1356
}

/*
 * 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
1357
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
1358 1359 1360 1361 1362 1363 1364 1365
 * 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.
 */
1366
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
1367 1368 1369 1370 1371
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

1372
	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383
		/*
		 * 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.)
		 *
1384
		 * NB. EXT4_STATE_JDATA is not set on files other than
1385 1386 1387 1388 1389 1390
		 * 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.
		 */

1391 1392
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
1393 1394 1395
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
1396 1397 1398 1399 1400

		if (err)
			return 0;
	}

1401
	return generic_block_bmap(mapping,block,ext4_get_block);
1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415
}

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;
}

1416
static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1417 1418
{
	if (buffer_mapped(bh))
1419
		return ext4_journal_dirty_data(handle, bh);
1420 1421 1422 1423 1424 1425
	return 0;
}

/*
 * Note that we always start a transaction even if we're not journalling
 * data.  This is to preserve ordering: any hole instantiation within
1426
 * __block_write_full_page -> ext4_get_block() should be journalled
1427 1428 1429 1430 1431 1432 1433
 * along with the data so we don't crash and then get metadata which
 * refers to old data.
 *
 * In all journalling modes block_write_full_page() will start the I/O.
 *
 * Problem:
 *
1434 1435
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
1436 1437 1438
 *
 * Similar for:
 *
1439
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1440
 *
1441
 * Same applies to ext4_get_block().  We will deadlock on various things like
1442
 * lock_journal and i_data_sem
1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474
 *
 * Setting PF_MEMALLOC here doesn't work - too many internal memory
 * allocations fail.
 *
 * 16May01: If we're reentered then journal_current_handle() will be
 *	    non-zero. We simply *return*.
 *
 * 1 July 2001: @@@ FIXME:
 *   In journalled data mode, a data buffer may be metadata against the
 *   current transaction.  But the same file is part of a shared mapping
 *   and someone does a writepage() on it.
 *
 *   We will move the buffer onto the async_data list, but *after* it has
 *   been dirtied. So there's a small window where we have dirty data on
 *   BJ_Metadata.
 *
 *   Note that this only applies to the last partial page in the file.  The
 *   bit which block_write_full_page() uses prepare/commit for.  (That's
 *   broken code anyway: it's wrong for msync()).
 *
 *   It's a rare case: affects the final partial page, for journalled data
 *   where the file is subject to bith write() and writepage() in the same
 *   transction.  To fix it we'll need a custom block_write_full_page().
 *   We'll probably need that anyway for journalling writepage() output.
 *
 * We don't honour synchronous mounts for writepage().  That would be
 * disastrous.  Any write() or metadata operation will sync the fs for
 * us.
 *
 * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
 * we don't need to open a transaction here.
 */
1475
static int ext4_ordered_writepage(struct page *page,
1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct buffer_head *page_bufs;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	J_ASSERT(PageLocked(page));

	/*
	 * We give up here if we're reentered, because it might be for a
	 * different filesystem.
	 */
1490
	if (ext4_journal_current_handle())
1491 1492
		goto out_fail;

1493
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507

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

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

1508
	ret = block_write_full_page(page, ext4_get_block, wbc);
1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523

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

	/*
	 * And attach them to the current transaction.  But only if
	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
	 * and generally junk.
	 */
	if (ret == 0) {
		err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1524
					NULL, jbd2_journal_dirty_data_fn);
1525 1526 1527 1528 1529
		if (!ret)
			ret = err;
	}
	walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, bput_one);
1530
	err = ext4_journal_stop(handle);
1531 1532 1533 1534 1535 1536 1537 1538 1539 1540
	if (!ret)
		ret = err;
	return ret;

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

1541
static int ext4_writeback_writepage(struct page *page,
1542 1543 1544 1545 1546 1547 1548
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

1549
	if (ext4_journal_current_handle())
1550 1551
		goto out_fail;

1552
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1553 1554 1555 1556 1557
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto out_fail;
	}

1558 1559
	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
		ret = nobh_writepage(page, ext4_get_block, wbc);
1560
	else
1561
		ret = block_write_full_page(page, ext4_get_block, wbc);
1562

1563
	err = ext4_journal_stop(handle);
1564 1565 1566 1567 1568 1569 1570 1571 1572 1573
	if (!ret)
		ret = err;
	return ret;

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

1574
static int ext4_journalled_writepage(struct page *page,
1575 1576 1577 1578 1579 1580 1581
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

1582
	if (ext4_journal_current_handle())
1583 1584
		goto no_write;

1585
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		goto no_write;
	}

	if (!page_has_buffers(page) || PageChecked(page)) {
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
1598
					ext4_get_block);
1599
		if (ret != 0) {
1600
			ext4_journal_stop(handle);
1601 1602 1603 1604 1605 1606
			goto out_unlock;
		}
		ret = walk_page_buffers(handle, page_buffers(page), 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);

		err = walk_page_buffers(handle, page_buffers(page), 0,
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Nick Piggin 已提交
1607
				PAGE_CACHE_SIZE, NULL, write_end_fn);
1608 1609
		if (ret == 0)
			ret = err;
1610
		EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1611 1612 1613 1614 1615 1616 1617
		unlock_page(page);
	} else {
		/*
		 * It may be a page full of checkpoint-mode buffers.  We don't
		 * really know unless we go poke around in the buffer_heads.
		 * But block_write_full_page will do the right thing.
		 */
1618
		ret = block_write_full_page(page, ext4_get_block, wbc);
1619
	}
1620
	err = ext4_journal_stop(handle);
1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
	if (!ret)
		ret = err;
out:
	return ret;

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

1633
static int ext4_readpage(struct file *file, struct page *page)
1634
{
1635
	return mpage_readpage(page, ext4_get_block);
1636 1637 1638
}

static int
1639
ext4_readpages(struct file *file, struct address_space *mapping,
1640 1641
		struct list_head *pages, unsigned nr_pages)
{
1642
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
1643 1644
}

1645
static void ext4_invalidatepage(struct page *page, unsigned long offset)
1646
{
1647
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1648 1649 1650 1651 1652 1653 1654

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

1655
	jbd2_journal_invalidatepage(journal, page, offset);
1656 1657
}

1658
static int ext4_releasepage(struct page *page, gfp_t wait)
1659
{
1660
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1661 1662 1663 1664

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
1665
	return jbd2_journal_try_to_free_buffers(journal, page, wait);
1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
}

/*
 * If the O_DIRECT write will extend the file then add this inode to the
 * orphan list.  So recovery will truncate it back to the original size
 * if the machine crashes during the write.
 *
 * If the O_DIRECT write is intantiating holes inside i_size and the machine
 * crashes then stale disk data _may_ be exposed inside the file.
 */
1676
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
1677 1678 1679 1680 1681
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
1682
	struct ext4_inode_info *ei = EXT4_I(inode);
1683 1684 1685 1686 1687 1688 1689 1690
	handle_t *handle = NULL;
	ssize_t ret;
	int orphan = 0;
	size_t count = iov_length(iov, nr_segs);

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

1691
		handle = ext4_journal_start(inode, DIO_CREDITS);
1692 1693 1694 1695 1696
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			goto out;
		}
		if (final_size > inode->i_size) {
1697
			ret = ext4_orphan_add(handle, inode);
1698 1699 1700 1701 1702 1703 1704 1705 1706
			if (ret)
				goto out_stop;
			orphan = 1;
			ei->i_disksize = inode->i_size;
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
1707
				 ext4_get_block, NULL);
1708 1709

	/*
1710
	 * Reacquire the handle: ext4_get_block() can restart the transaction
1711
	 */
1712
	handle = ext4_journal_current_handle();
1713 1714 1715 1716 1717 1718

out_stop:
	if (handle) {
		int err;

		if (orphan && inode->i_nlink)
1719
			ext4_orphan_del(handle, inode);
1720 1721 1722 1723 1724 1725 1726 1727 1728
		if (orphan && ret > 0) {
			loff_t end = offset + ret;
			if (end > inode->i_size) {
				ei->i_disksize = end;
				i_size_write(inode, end);
				/*
				 * We're going to return a positive `ret'
				 * here due to non-zero-length I/O, so there's
				 * no way of reporting error returns from
1729
				 * ext4_mark_inode_dirty() to userspace.  So
1730 1731
				 * ignore it.
				 */
1732
				ext4_mark_inode_dirty(handle, inode);
1733 1734
			}
		}
1735
		err = ext4_journal_stop(handle);
1736 1737 1738 1739 1740 1741 1742 1743
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
1744
 * Pages can be marked dirty completely asynchronously from ext4's journalling
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
 * 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.
 */
1756
static int ext4_journalled_set_page_dirty(struct page *page)
1757 1758 1759 1760 1761
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

1762 1763 1764 1765
static const struct address_space_operations ext4_ordered_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_ordered_writepage,
1766
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1767 1768
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_ordered_write_end,
1769 1770 1771 1772
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1773 1774 1775
	.migratepage	= buffer_migrate_page,
};

1776 1777 1778 1779
static const struct address_space_operations ext4_writeback_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_writeback_writepage,
1780
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1781 1782
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_writeback_write_end,
1783 1784 1785 1786
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1787 1788 1789
	.migratepage	= buffer_migrate_page,
};

1790 1791 1792 1793
static const struct address_space_operations ext4_journalled_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_journalled_writepage,
1794
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1795 1796
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_journalled_write_end,
1797 1798 1799 1800
	.set_page_dirty	= ext4_journalled_set_page_dirty,
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
1801 1802
};

1803
void ext4_set_aops(struct inode *inode)
1804
{
1805 1806 1807 1808
	if (ext4_should_order_data(inode))
		inode->i_mapping->a_ops = &ext4_ordered_aops;
	else if (ext4_should_writeback_data(inode))
		inode->i_mapping->a_ops = &ext4_writeback_aops;
1809
	else
1810
		inode->i_mapping->a_ops = &ext4_journalled_aops;
1811 1812 1813
}

/*
1814
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
1815 1816 1817 1818
 * up to the end of the block which corresponds to `from'.
 * This required during truncate. We need to physically zero the tail end
 * of that block so it doesn't yield old data if the file is later grown.
 */
A
Alex Tomas 已提交
1819
int ext4_block_truncate_page(handle_t *handle, struct page *page,
1820 1821
		struct address_space *mapping, loff_t from)
{
1822
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1823
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
A
Aneesh Kumar K.V 已提交
1824 1825
	unsigned blocksize, length, pos;
	ext4_lblk_t iblock;
1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
	int err = 0;

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

	/*
	 * For "nobh" option,  we can only work if we don't need to
	 * read-in the page - otherwise we create buffers to do the IO.
	 */
	if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
1839
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
1840
		zero_user(page, offset, length);
1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864
		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");
1865
		ext4_get_block(inode, iblock, bh, 0);
1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
		/* 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;
	}

1886
	if (ext4_should_journal_data(inode)) {
1887
		BUFFER_TRACE(bh, "get write access");
1888
		err = ext4_journal_get_write_access(handle, bh);
1889 1890 1891 1892
		if (err)
			goto unlock;
	}

1893
	zero_user(page, offset, length);
1894 1895 1896 1897

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

	err = 0;
1898 1899
	if (ext4_should_journal_data(inode)) {
		err = ext4_journal_dirty_metadata(handle, bh);
1900
	} else {
1901 1902
		if (ext4_should_order_data(inode))
			err = ext4_journal_dirty_data(handle, bh);
1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925
		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;
}

/**
1926
 *	ext4_find_shared - find the indirect blocks for partial truncation.
1927 1928
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
1929
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
1930 1931 1932
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
1933
 *	This is a helper function used by ext4_truncate().
1934 1935 1936 1937 1938 1939 1940
 *
 *	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
1941
 *	past the truncation point is possible until ext4_truncate()
1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959
 *	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).  */

1960
static Indirect *ext4_find_shared(struct inode *inode, int depth,
A
Aneesh Kumar K.V 已提交
1961
			ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
1962 1963 1964 1965 1966 1967 1968 1969
{
	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--)
		;
1970
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
	/* Writer: pointers */
	if (!partial)
		partial = chain + k-1;
	/*
	 * If the branch acquired continuation since we've looked at it -
	 * fine, it should all survive and (new) top doesn't belong to us.
	 */
	if (!partial->key && *partial->p)
		/* Writer: end */
		goto no_top;
	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
		;
	/*
	 * OK, we've found the last block that must survive. The rest of our
	 * branch should be detached before unlocking. However, if that rest
	 * of branch is all ours and does not grow immediately from the inode
	 * it's easier to cheat and just decrement partial->p.
	 */
	if (p == chain + k - 1 && p > chain) {
		p->p--;
	} else {
		*top = *p->p;
1993
		/* Nope, don't do this in ext4.  Must leave the tree intact */
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
#if 0
		*p->p = 0;
#endif
	}
	/* Writer: end */

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

/*
 * Zero a number of block pointers in either an inode or an indirect block.
 * If we restart the transaction we must again get write access to the
 * indirect block for further modification.
 *
 * We release `count' blocks on disk, but (last - first) may be greater
 * than `count' because there can be holes in there.
 */
2016 2017
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
2018 2019 2020 2021 2022
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
2023 2024
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			ext4_journal_dirty_metadata(handle, bh);
2025
		}
2026 2027
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
2028 2029
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
2030
			ext4_journal_get_write_access(handle, bh);
2031 2032 2033 2034 2035
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
2036
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
2037
	 * on them.  We've already detached each block from the file, so
2038
	 * bforget() in jbd2_journal_forget() should be safe.
2039
	 *
2040
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
2041 2042 2043 2044
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
A
Aneesh Kumar K.V 已提交
2045
			struct buffer_head *tbh;
2046 2047

			*p = 0;
A
Aneesh Kumar K.V 已提交
2048 2049
			tbh = sb_find_get_block(inode->i_sb, nr);
			ext4_forget(handle, 0, inode, tbh, nr);
2050 2051 2052
		}
	}

2053
	ext4_free_blocks(handle, inode, block_to_free, count, 0);
2054 2055 2056
}

/**
2057
 * ext4_free_data - free a list of data blocks
2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074
 * @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.
 */
2075
static void ext4_free_data(handle_t *handle, struct inode *inode,
2076 2077 2078
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
2079
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2080 2081 2082 2083
	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 */
2084
	ext4_fsblk_t nr;		    /* Current block # */
2085 2086 2087 2088 2089 2090
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
2091
		err = ext4_journal_get_write_access(handle, this_bh);
2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108
		/* 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 {
2109
				ext4_clear_blocks(handle, inode, this_bh,
2110 2111 2112 2113 2114 2115 2116 2117 2118 2119
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
2120
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
2121 2122 2123
				  count, block_to_free_p, p);

	if (this_bh) {
2124 2125
		BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
		ext4_journal_dirty_metadata(handle, this_bh);
2126 2127 2128 2129
	}
}

/**
2130
 *	ext4_free_branches - free an array of branches
2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141
 *	@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.
 */
2142
static void ext4_free_branches(handle_t *handle, struct inode *inode,
2143 2144 2145
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
2146
	ext4_fsblk_t nr;
2147 2148 2149 2150 2151 2152 2153
	__le32 *p;

	if (is_handle_aborted(handle))
		return;

	if (depth--) {
		struct buffer_head *bh;
2154
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168
		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) {
2169
				ext4_error(inode->i_sb, "ext4_free_branches",
2170
					   "Read failure, inode=%lu, block=%llu",
2171 2172 2173 2174 2175 2176
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
2177
			ext4_free_branches(handle, inode, bh,
2178 2179 2180 2181 2182 2183 2184 2185
					   (__le32*)bh->b_data,
					   (__le32*)bh->b_data + addr_per_block,
					   depth);

			/*
			 * We've probably journalled the indirect block several
			 * times during the truncate.  But it's no longer
			 * needed and we now drop it from the transaction via
2186
			 * jbd2_journal_revoke().
2187 2188 2189
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
2190
			 * transaction then jbd2_journal_forget() will simply
2191
			 * brelse() it.  That means that if the underlying
2192
			 * block is reallocated in ext4_get_block(),
2193 2194 2195 2196 2197 2198 2199 2200
			 * 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.
			 */
2201
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221

			/*
			 * Everything below this this pointer has been
			 * released.  Now let this top-of-subtree go.
			 *
			 * We want the freeing of this indirect block to be
			 * atomic in the journal with the updating of the
			 * bitmap block which owns it.  So make some room in
			 * the journal.
			 *
			 * We zero the parent pointer *after* freeing its
			 * pointee in the bitmaps, so if extend_transaction()
			 * for some reason fails to put the bitmap changes and
			 * the release into the same transaction, recovery
			 * will merely complain about releasing a free block,
			 * rather than leaking blocks.
			 */
			if (is_handle_aborted(handle))
				return;
			if (try_to_extend_transaction(handle, inode)) {
2222 2223
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
2224 2225
			}

2226
			ext4_free_blocks(handle, inode, nr, 1, 1);
2227 2228 2229 2230 2231 2232 2233

			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");
2234
				if (!ext4_journal_get_write_access(handle,
2235 2236 2237
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
2238 2239
					"call ext4_journal_dirty_metadata");
					ext4_journal_dirty_metadata(handle,
2240 2241 2242 2243 2244 2245 2246
								    parent_bh);
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
2247
		ext4_free_data(handle, inode, parent_bh, first, last);
2248 2249 2250 2251
	}
}

/*
2252
 * ext4_truncate()
2253
 *
2254 2255
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271
 * 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
2272
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
2273
 * that this inode's truncate did not complete and it will again call
2274 2275
 * 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
2276
 * that's fine - as long as they are linked from the inode, the post-crash
2277
 * ext4_truncate() run will find them and release them.
2278
 */
2279
void ext4_truncate(struct inode *inode)
2280 2281
{
	handle_t *handle;
2282
	struct ext4_inode_info *ei = EXT4_I(inode);
2283
	__le32 *i_data = ei->i_data;
2284
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2285
	struct address_space *mapping = inode->i_mapping;
A
Aneesh Kumar K.V 已提交
2286
	ext4_lblk_t offsets[4];
2287 2288 2289 2290
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
A
Aneesh Kumar K.V 已提交
2291
	ext4_lblk_t last_block;
2292 2293 2294 2295 2296 2297
	unsigned blocksize = inode->i_sb->s_blocksize;
	struct page *page;

	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
	    S_ISLNK(inode->i_mode)))
		return;
2298
	if (ext4_inode_is_fast_symlink(inode))
2299 2300 2301 2302 2303 2304
		return;
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return;

	/*
	 * We have to lock the EOF page here, because lock_page() nests
2305
	 * outside jbd2_journal_start().
2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316
	 */
	if ((inode->i_size & (blocksize - 1)) == 0) {
		/* Block boundary? Nothing to do */
		page = NULL;
	} else {
		page = grab_cache_page(mapping,
				inode->i_size >> PAGE_CACHE_SHIFT);
		if (!page)
			return;
	}

A
Aneesh Kumar K.V 已提交
2317 2318 2319 2320
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
		ext4_ext_truncate(inode, page);
		return;
	}
A
Alex Tomas 已提交
2321

2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333
	handle = start_transaction(inode);
	if (IS_ERR(handle)) {
		if (page) {
			clear_highpage(page);
			flush_dcache_page(page);
			unlock_page(page);
			page_cache_release(page);
		}
		return;		/* AKPM: return what? */
	}

	last_block = (inode->i_size + blocksize-1)
2334
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
2335 2336

	if (page)
2337
		ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2338

2339
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351
	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.
	 */
2352
	if (ext4_orphan_add(handle, inode))
2353 2354 2355 2356 2357 2358 2359
		goto out_stop;

	/*
	 * The orphan list entry will now protect us from any crash which
	 * occurs before the truncate completes, so it is now safe to propagate
	 * the new, shorter inode size (held for now in i_size) into the
	 * on-disk inode. We do this via i_disksize, which is the value which
2360
	 * ext4 *really* writes onto the disk inode.
2361 2362 2363 2364
	 */
	ei->i_disksize = inode->i_size;

	/*
2365
	 * From here we block out all ext4_get_block() callers who want to
2366 2367
	 * modify the block allocation tree.
	 */
2368
	down_write(&ei->i_data_sem);
2369 2370

	if (n == 1) {		/* direct blocks */
2371 2372
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
2373 2374 2375
		goto do_indirects;
	}

2376
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
2377 2378 2379 2380
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
2381
			ext4_free_branches(handle, inode, NULL,
2382 2383 2384 2385 2386 2387 2388 2389 2390
					   &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");
2391
			ext4_free_branches(handle, inode, partial->bh,
2392 2393 2394 2395 2396 2397
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
2398
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
2399 2400 2401 2402 2403 2404 2405 2406 2407 2408
				   (__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:
2409
		nr = i_data[EXT4_IND_BLOCK];
2410
		if (nr) {
2411 2412
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
2413
		}
2414 2415
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
2416
		if (nr) {
2417 2418
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
2419
		}
2420 2421
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
2422
		if (nr) {
2423 2424
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
2425
		}
2426
	case EXT4_TIND_BLOCK:
2427 2428 2429
		;
	}

2430
	ext4_discard_reservation(inode);
2431

2432
	up_write(&ei->i_data_sem);
K
Kalpak Shah 已提交
2433
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
2434
	ext4_mark_inode_dirty(handle, inode);
2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446

	/*
	 * In a multi-transaction truncate, we only make the final transaction
	 * synchronous
	 */
	if (IS_SYNC(inode))
		handle->h_sync = 1;
out_stop:
	/*
	 * If this was a simple ftruncate(), and the file will remain alive
	 * then we need to clear up the orphan record which we created above.
	 * However, if this was a real unlink then we were called by
2447
	 * ext4_delete_inode(), and we allow that function to clean up the
2448 2449 2450
	 * orphan info for us.
	 */
	if (inode->i_nlink)
2451
		ext4_orphan_del(handle, inode);
2452

2453
	ext4_journal_stop(handle);
2454 2455
}

2456 2457
static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
		unsigned long ino, struct ext4_iloc *iloc)
2458
{
2459 2460
	unsigned long desc, group_desc;
	ext4_group_t block_group;
2461
	unsigned long offset;
2462
	ext4_fsblk_t block;
2463
	struct buffer_head *bh;
2464
	struct ext4_group_desc * gdp;
2465

2466
	if (!ext4_valid_inum(sb, ino)) {
2467 2468 2469 2470 2471 2472 2473 2474
		/*
		 * This error is already checked for in namei.c unless we are
		 * looking at an NFS filehandle, in which case no error
		 * report is needed
		 */
		return 0;
	}

2475 2476 2477
	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
	if (block_group >= EXT4_SB(sb)->s_groups_count) {
		ext4_error(sb,"ext4_get_inode_block","group >= groups count");
2478 2479 2480
		return 0;
	}
	smp_rmb();
2481 2482 2483
	group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
	desc = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
	bh = EXT4_SB(sb)->s_group_desc[group_desc];
2484
	if (!bh) {
2485
		ext4_error (sb, "ext4_get_inode_block",
2486 2487 2488 2489
			    "Descriptor not loaded");
		return 0;
	}

2490 2491
	gdp = (struct ext4_group_desc *)((__u8 *)bh->b_data +
		desc * EXT4_DESC_SIZE(sb));
2492 2493 2494
	/*
	 * Figure out the offset within the block group inode table
	 */
2495 2496
	offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
		EXT4_INODE_SIZE(sb);
2497 2498
	block = ext4_inode_table(sb, gdp) +
		(offset >> EXT4_BLOCK_SIZE_BITS(sb));
2499 2500

	iloc->block_group = block_group;
2501
	iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
2502 2503 2504 2505
	return block;
}

/*
2506
 * ext4_get_inode_loc returns with an extra refcount against the inode's
2507 2508 2509 2510
 * 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.
 */
2511 2512
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
2513
{
2514
	ext4_fsblk_t block;
2515 2516
	struct buffer_head *bh;

2517
	block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2518 2519 2520 2521 2522
	if (!block)
		return -EIO;

	bh = sb_getblk(inode->i_sb, block);
	if (!bh) {
2523
		ext4_error (inode->i_sb, "ext4_get_inode_loc",
2524
				"unable to read inode block - "
2525
				"inode=%lu, block=%llu",
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543
				 inode->i_ino, block);
		return -EIO;
	}
	if (!buffer_uptodate(bh)) {
		lock_buffer(bh);
		if (buffer_uptodate(bh)) {
			/* someone brought it uptodate while we waited */
			unlock_buffer(bh);
			goto has_buffer;
		}

		/*
		 * If we have all information of the inode in memory and this
		 * is the only valid inode in the block, we need not read the
		 * block.
		 */
		if (in_mem) {
			struct buffer_head *bitmap_bh;
2544
			struct ext4_group_desc *desc;
2545 2546
			int inodes_per_buffer;
			int inode_offset, i;
2547
			ext4_group_t block_group;
2548 2549 2550
			int start;

			block_group = (inode->i_ino - 1) /
2551
					EXT4_INODES_PER_GROUP(inode->i_sb);
2552
			inodes_per_buffer = bh->b_size /
2553
				EXT4_INODE_SIZE(inode->i_sb);
2554
			inode_offset = ((inode->i_ino - 1) %
2555
					EXT4_INODES_PER_GROUP(inode->i_sb));
2556 2557 2558
			start = inode_offset & ~(inodes_per_buffer - 1);

			/* Is the inode bitmap in cache? */
2559
			desc = ext4_get_group_desc(inode->i_sb,
2560 2561 2562 2563 2564
						block_group, NULL);
			if (!desc)
				goto make_io;

			bitmap_bh = sb_getblk(inode->i_sb,
2565
				ext4_inode_bitmap(inode->i_sb, desc));
2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580
			if (!bitmap_bh)
				goto make_io;

			/*
			 * If the inode bitmap isn't in cache then the
			 * optimisation may end up performing two reads instead
			 * of one, so skip it.
			 */
			if (!buffer_uptodate(bitmap_bh)) {
				brelse(bitmap_bh);
				goto make_io;
			}
			for (i = start; i < start + inodes_per_buffer; i++) {
				if (i == inode_offset)
					continue;
2581
				if (ext4_test_bit(i, bitmap_bh->b_data))
2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604
					break;
			}
			brelse(bitmap_bh);
			if (i == start + inodes_per_buffer) {
				/* all other inodes are free, so skip I/O */
				memset(bh->b_data, 0, bh->b_size);
				set_buffer_uptodate(bh);
				unlock_buffer(bh);
				goto has_buffer;
			}
		}

make_io:
		/*
		 * There are other valid inodes in the buffer, this inode
		 * has in-inode xattrs, or we don't have this inode in memory.
		 * Read the block from disk.
		 */
		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ_META, bh);
		wait_on_buffer(bh);
		if (!buffer_uptodate(bh)) {
2605
			ext4_error(inode->i_sb, "ext4_get_inode_loc",
2606
					"unable to read inode block - "
2607
					"inode=%lu, block=%llu",
2608 2609 2610 2611 2612 2613 2614 2615 2616 2617
					inode->i_ino, block);
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

2618
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
2619 2620
{
	/* We have all inode data except xattrs in memory here. */
2621 2622
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
2623 2624
}

2625
void ext4_set_inode_flags(struct inode *inode)
2626
{
2627
	unsigned int flags = EXT4_I(inode)->i_flags;
2628 2629

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2630
	if (flags & EXT4_SYNC_FL)
2631
		inode->i_flags |= S_SYNC;
2632
	if (flags & EXT4_APPEND_FL)
2633
		inode->i_flags |= S_APPEND;
2634
	if (flags & EXT4_IMMUTABLE_FL)
2635
		inode->i_flags |= S_IMMUTABLE;
2636
	if (flags & EXT4_NOATIME_FL)
2637
		inode->i_flags |= S_NOATIME;
2638
	if (flags & EXT4_DIRSYNC_FL)
2639 2640 2641
		inode->i_flags |= S_DIRSYNC;
}

2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659
/* 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;
}
2660 2661 2662 2663
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
2664 2665
	struct inode *inode = &(ei->vfs_inode);
	struct super_block *sb = inode->i_sb;
2666 2667 2668 2669 2670 2671

	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
2672 2673 2674 2675 2676 2677
		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;
		}
2678 2679 2680 2681
	} else {
		return le32_to_cpu(raw_inode->i_blocks_lo);
	}
}
2682

2683
void ext4_read_inode(struct inode * inode)
2684
{
2685 2686 2687
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
	struct ext4_inode_info *ei = EXT4_I(inode);
2688 2689 2690
	struct buffer_head *bh;
	int block;

2691 2692 2693
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
2694 2695 2696
#endif
	ei->i_block_alloc_info = NULL;

2697
	if (__ext4_get_inode_loc(inode, &iloc, 0))
2698 2699
		goto bad_inode;
	bh = iloc.bh;
2700
	raw_inode = ext4_raw_inode(&iloc);
2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719
	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
	inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
	if(!(test_opt (inode->i_sb, NO_UID32))) {
		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
	}
	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);

	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 ||
2720
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
2721 2722 2723 2724 2725 2726 2727 2728 2729 2730
			/* this inode is deleted */
			brelse (bh);
			goto bad_inode;
		}
		/* The only unlinked inodes we let through here have
		 * valid i_mode and are being read by the orphan
		 * recovery code: that's fine, we're about to complete
		 * the process of deleting those. */
	}
	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2731
	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
2732
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
2733
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
2734
	    cpu_to_le32(EXT4_OS_HURD)) {
B
Badari Pulavarty 已提交
2735 2736
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
2737
	}
2738
	inode->i_size = ext4_isize(raw_inode);
2739 2740 2741 2742 2743 2744 2745
	ei->i_disksize = inode->i_size;
	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
	ei->i_block_group = iloc.block_group;
	/*
	 * NOTE! The in-memory inode i_data array is in little-endian order
	 * even on big-endian machines: we do NOT byteswap the block numbers!
	 */
2746
	for (block = 0; block < EXT4_N_BLOCKS; block++)
2747 2748 2749
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

2750 2751
	if (inode->i_ino >= EXT4_FIRST_INO(inode->i_sb) + 1 &&
	    EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
2752 2753
		/*
		 * When mke2fs creates big inodes it does not zero out
2754
		 * the unused bytes above EXT4_GOOD_OLD_INODE_SIZE,
2755 2756 2757
		 * so ignore those first few inodes.
		 */
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2758
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2759 2760
		    EXT4_INODE_SIZE(inode->i_sb)) {
			brelse (bh);
2761
			goto bad_inode;
2762
		}
2763 2764
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
2765 2766
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
2767 2768
		} else {
			__le32 *magic = (void *)raw_inode +
2769
					EXT4_GOOD_OLD_INODE_SIZE +
2770
					ei->i_extra_isize;
2771 2772
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
2773 2774 2775 2776
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
2777 2778 2779 2780 2781
	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);

2782 2783 2784 2785 2786 2787 2788
	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;
	}

2789
	if (S_ISREG(inode->i_mode)) {
2790 2791 2792
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
2793
	} else if (S_ISDIR(inode->i_mode)) {
2794 2795
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
2796
	} else if (S_ISLNK(inode->i_mode)) {
2797 2798
		if (ext4_inode_is_fast_symlink(inode))
			inode->i_op = &ext4_fast_symlink_inode_operations;
2799
		else {
2800 2801
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
2802 2803
		}
	} else {
2804
		inode->i_op = &ext4_special_inode_operations;
2805 2806 2807 2808 2809 2810 2811 2812
		if (raw_inode->i_block[0])
			init_special_inode(inode, inode->i_mode,
			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
		else
			init_special_inode(inode, inode->i_mode,
			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
	}
	brelse (iloc.bh);
2813
	ext4_set_inode_flags(inode);
2814 2815 2816 2817 2818 2819 2820
	return;

bad_inode:
	make_bad_inode(inode);
	return;
}

2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834
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;
	int err = 0;

	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
2835
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
2836
		raw_inode->i_blocks_high = 0;
A
Aneesh Kumar K.V 已提交
2837
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
2838 2839 2840 2841 2842 2843 2844 2845 2846 2847
	} else if (i_blocks <= 0xffffffffffffULL) {
		/*
		 * i_blocks can be represented in a 48 bit variable
		 * as multiple of 512 bytes
		 */
		err = ext4_update_rocompat_feature(handle, sb,
					    EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
		if (err)
			goto  err_out;
		/* i_block is stored in the split  48 bit fields */
A
Aneesh Kumar K.V 已提交
2848
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
2849
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
A
Aneesh Kumar K.V 已提交
2850
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
2851
	} else {
A
Aneesh Kumar K.V 已提交
2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864
		/*
		 * i_blocks should be represented in a 48 bit variable
		 * as multiple of  file system block size
		 */
		err = ext4_update_rocompat_feature(handle, sb,
					    EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
		if (err)
			goto  err_out;
		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);
2865 2866 2867 2868 2869
	}
err_out:
	return err;
}

2870 2871 2872 2873 2874 2875 2876
/*
 * 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.
 */
2877
static int ext4_do_update_inode(handle_t *handle,
2878
				struct inode *inode,
2879
				struct ext4_iloc *iloc)
2880
{
2881 2882
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
2883 2884 2885 2886 2887
	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. */
2888 2889
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
2890

2891
	ext4_get_inode_flags(ei);
2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917
	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
	if(!(test_opt(inode->i_sb, NO_UID32))) {
		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
/*
 * Fix up interoperability with old kernels. Otherwise, old inodes get
 * re-used with the upper 16 bits of the uid/gid intact
 */
		if(!ei->i_dtime) {
			raw_inode->i_uid_high =
				cpu_to_le16(high_16_bits(inode->i_uid));
			raw_inode->i_gid_high =
				cpu_to_le16(high_16_bits(inode->i_gid));
		} else {
			raw_inode->i_uid_high = 0;
			raw_inode->i_gid_high = 0;
		}
	} else {
		raw_inode->i_uid_low =
			cpu_to_le16(fs_high2lowuid(inode->i_uid));
		raw_inode->i_gid_low =
			cpu_to_le16(fs_high2lowgid(inode->i_gid));
		raw_inode->i_uid_high = 0;
		raw_inode->i_gid_high = 0;
	}
	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
K
Kalpak Shah 已提交
2918 2919 2920 2921 2922 2923

	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);

2924 2925
	if (ext4_inode_blocks_set(handle, raw_inode, ei))
		goto out_brelse;
2926 2927
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
2928 2929
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
2930 2931
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
2932
	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948
	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,
2949
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
2950 2951 2952 2953
			sb->s_dirt = 1;
			handle->h_sync = 1;
			err = ext4_journal_dirty_metadata(handle,
					EXT4_SB(sb)->s_sbh);
2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967
		}
	}
	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;
		}
2968
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
2969 2970
		raw_inode->i_block[block] = ei->i_data[block];

2971 2972 2973 2974 2975
	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);
2976
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
2977 2978
	}

2979

2980 2981
	BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
	rc = ext4_journal_dirty_metadata(handle, bh);
2982 2983
	if (!err)
		err = rc;
2984
	ei->i_state &= ~EXT4_STATE_NEW;
2985 2986 2987

out_brelse:
	brelse (bh);
2988
	ext4_std_error(inode->i_sb, err);
2989 2990 2991 2992
	return err;
}

/*
2993
 * ext4_write_inode()
2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009
 *
 * 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
3010
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026
 * 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.
 */
3027
int ext4_write_inode(struct inode *inode, int wait)
3028 3029 3030 3031
{
	if (current->flags & PF_MEMALLOC)
		return 0;

3032
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
3033
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3034 3035 3036 3037 3038 3039 3040
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

3041
	return ext4_force_commit(inode->i_sb);
3042 3043 3044
}

/*
3045
 * ext4_setattr()
3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060
 *
 * Called from notify_change.
 *
 * We want to trap VFS attempts to truncate the file as soon as
 * possible.  In particular, we want to make sure that when the VFS
 * shrinks i_size, we put the inode on the orphan list and modify
 * i_disksize immediately, so that during the subsequent flushing of
 * dirty pages and freeing of disk blocks, we can guarantee that any
 * commit will leave the blocks being flushed in an unused state on
 * disk.  (On recovery, the inode will get truncated and the blocks will
 * be freed, so we have a strong guarantee that no future commit will
 * leave these blocks visible to the user.)
 *
 * Called with inode->sem down.
 */
3061
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076
{
	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) */
3077 3078
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
3079 3080 3081 3082 3083 3084
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
		if (error) {
3085
			ext4_journal_stop(handle);
3086 3087 3088 3089 3090 3091 3092 3093
			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;
3094 3095
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
3096 3097
	}

3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108
	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;
			}
		}
	}

3109 3110 3111 3112
	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

3113
		handle = ext4_journal_start(inode, 3);
3114 3115 3116 3117 3118
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

3119 3120 3121
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
3122 3123
		if (!error)
			error = rc;
3124
		ext4_journal_stop(handle);
3125 3126 3127 3128
	}

	rc = inode_setattr(inode, attr);

3129
	/* If inode_setattr's call to ext4_truncate failed to get a
3130 3131 3132
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
3133
		ext4_orphan_del(NULL, inode);
3134 3135

	if (!rc && (ia_valid & ATTR_MODE))
3136
		rc = ext4_acl_chmod(inode);
3137 3138

err_out:
3139
	ext4_std_error(inode->i_sb, error);
3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157
	if (!error)
		error = rc;
	return error;
}


/*
 * How many blocks doth make a writepage()?
 *
 * With N blocks per page, it may be:
 * N data blocks
 * 2 indirect block
 * 2 dindirect
 * 1 tindirect
 * N+5 bitmap blocks (from the above)
 * N+5 group descriptor summary blocks
 * 1 inode block
 * 1 superblock.
3158
 * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
3159
 *
3160
 * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172
 *
 * With ordered or writeback data it's the same, less the N data blocks.
 *
 * If the inode's direct blocks can hold an integral number of pages then a
 * page cannot straddle two indirect blocks, and we can only touch one indirect
 * and dindirect block, and the "5" above becomes "3".
 *
 * This still overestimates under most circumstances.  If we were to pass the
 * start and end offsets in here as well we could do block_to_path() on each
 * block and work out the exact number of indirects which are touched.  Pah.
 */

A
Alex Tomas 已提交
3173
int ext4_writepage_trans_blocks(struct inode *inode)
3174
{
3175 3176
	int bpp = ext4_journal_blocks_per_page(inode);
	int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
3177 3178
	int ret;

A
Alex Tomas 已提交
3179 3180 3181
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
		return ext4_ext_writepage_trans_blocks(inode, bpp);

3182
	if (ext4_should_journal_data(inode))
3183 3184 3185 3186 3187 3188 3189
		ret = 3 * (bpp + indirects) + 2;
	else
		ret = 2 * (bpp + indirects) + 2;

#ifdef CONFIG_QUOTA
	/* We know that structure was already allocated during DQUOT_INIT so
	 * we will be updating only the data blocks + inodes */
3190
	ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
3191 3192 3193 3194 3195 3196
#endif

	return ret;
}

/*
3197
 * The caller must have previously called ext4_reserve_inode_write().
3198 3199
 * Give this, we know that the caller already has write access to iloc->bh.
 */
3200 3201
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
3202 3203 3204
{
	int err = 0;

3205 3206 3207
	if (test_opt(inode->i_sb, I_VERSION))
		inode_inc_iversion(inode);

3208 3209 3210
	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

3211
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
3212
	err = ext4_do_update_inode(handle, inode, iloc);
3213 3214 3215 3216 3217 3218 3219 3220 3221 3222
	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
3223 3224
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
3225 3226 3227
{
	int err = 0;
	if (handle) {
3228
		err = ext4_get_inode_loc(inode, iloc);
3229 3230
		if (!err) {
			BUFFER_TRACE(iloc->bh, "get_write_access");
3231
			err = ext4_journal_get_write_access(handle, iloc->bh);
3232 3233 3234 3235 3236 3237
			if (err) {
				brelse(iloc->bh);
				iloc->bh = NULL;
			}
		}
	}
3238
	ext4_std_error(inode->i_sb, err);
3239 3240 3241
	return err;
}

3242 3243 3244 3245
/*
 * 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
3246 3247 3248 3249
static int ext4_expand_extra_isize(struct inode *inode,
				   unsigned int new_extra_isize,
				   struct ext4_iloc iloc,
				   handle_t *handle)
3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276
{
	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);
}

3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297
/*
 * 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.
 */
3298
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
3299
{
3300
	struct ext4_iloc iloc;
3301 3302 3303
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
3304 3305

	might_sleep();
3306
	err = ext4_reserve_inode_write(handle, inode, &iloc);
3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322
	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
	    !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
		/*
		 * We need extra buffer credits since we may write into EA block
		 * with this same handle. If journal_extend fails, then it will
		 * only result in a minor loss of functionality for that inode.
		 * If this is felt to be critical, then e2fsck should be run to
		 * force a large enough s_min_extra_isize.
		 */
		if ((jbd2_journal_extend(handle,
			     EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
			ret = ext4_expand_extra_isize(inode,
						      sbi->s_want_extra_isize,
						      iloc, handle);
			if (ret) {
				EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
A
Aneesh Kumar K.V 已提交
3323 3324
				if (mnt_count !=
					le16_to_cpu(sbi->s_es->s_mnt_count)) {
3325 3326 3327 3328
					ext4_warning(inode->i_sb, __FUNCTION__,
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
A
Aneesh Kumar K.V 已提交
3329 3330
					mnt_count =
					  le16_to_cpu(sbi->s_es->s_mnt_count);
3331 3332 3333 3334
				}
			}
		}
	}
3335
	if (!err)
3336
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
3337 3338 3339 3340
	return err;
}

/*
3341
 * ext4_dirty_inode() is called from __mark_inode_dirty()
3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353
 *
 * We're really interested in the case where a file is being extended.
 * i_size has been changed by generic_commit_write() and we thus need
 * to include the updated inode in the current transaction.
 *
 * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
 * are allocated to the file.
 *
 * If the inode is marked synchronous, we don't honour that here - doing
 * so would cause a commit on atime updates, which we don't bother doing.
 * We handle synchronous inodes at the highest possible level.
 */
3354
void ext4_dirty_inode(struct inode *inode)
3355
{
3356
	handle_t *current_handle = ext4_journal_current_handle();
3357 3358
	handle_t *handle;

3359
	handle = ext4_journal_start(inode, 2);
3360 3361 3362 3363 3364 3365 3366 3367 3368 3369
	if (IS_ERR(handle))
		goto out;
	if (current_handle &&
		current_handle->h_transaction != handle->h_transaction) {
		/* This task has a transaction open against a different fs */
		printk(KERN_EMERG "%s: transactions do not match!\n",
		       __FUNCTION__);
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
3370
		ext4_mark_inode_dirty(handle, inode);
3371
	}
3372
	ext4_journal_stop(handle);
3373 3374 3375 3376 3377 3378 3379 3380
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
3381
 * ext4_reserve_inode_write, this leaves behind no bh reference and
3382 3383 3384
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
3385
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
3386
{
3387
	struct ext4_iloc iloc;
3388 3389 3390

	int err = 0;
	if (handle) {
3391
		err = ext4_get_inode_loc(inode, &iloc);
3392 3393
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
3394
			err = jbd2_journal_get_write_access(handle, iloc.bh);
3395
			if (!err)
3396
				err = ext4_journal_dirty_metadata(handle,
3397 3398 3399 3400
								  iloc.bh);
			brelse(iloc.bh);
		}
	}
3401
	ext4_std_error(inode->i_sb, err);
3402 3403 3404 3405
	return err;
}
#endif

3406
int ext4_change_inode_journal_flag(struct inode *inode, int val)
3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421
{
	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.
	 */

3422
	journal = EXT4_JOURNAL(inode);
3423
	if (is_journal_aborted(journal))
3424 3425
		return -EROFS;

3426 3427
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
3428 3429 3430 3431 3432 3433 3434 3435 3436 3437

	/*
	 * 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)
3438
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
3439
	else
3440 3441
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
3442

3443
	jbd2_journal_unlock_updates(journal);
3444 3445 3446

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

3447
	handle = ext4_journal_start(inode, 1);
3448 3449 3450
	if (IS_ERR(handle))
		return PTR_ERR(handle);

3451
	err = ext4_mark_inode_dirty(handle, inode);
3452
	handle->h_sync = 1;
3453 3454
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
3455 3456 3457

	return err;
}