inode.c 104.9 KB
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/*
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 *  linux/fs/ext4/inode.c
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 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Goal-directed block allocation by Stephen Tweedie
 *	(sct@redhat.com), 1993, 1998
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 *  64-bit file support on 64-bit platforms by Jakub Jelinek
 *	(jj@sunsite.ms.mff.cuni.cz)
 *
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 *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
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 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/time.h>
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#include <linux/jbd2.h>
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#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/uio.h>
#include <linux/bio.h>
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#include "ext4_jbd2.h"
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#include "xattr.h"
#include "acl.h"

/*
 * 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, __func__,
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			   "error %d when attempting revoke", err);
	BUFFER_TRACE(bh, "exit");
	return err;
}

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

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

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

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

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

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

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

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

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

	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
348
 *      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;
}

/**
381
 *	ext4_find_near - find a place for allocation with sufficient locality
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 *	@inode: owner
 *	@ind: descriptor of indirect block.
 *
385
 *	This function returns the preferred place for block allocation.
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 *	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);
403 404
	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
	__le32 *p;
405
	ext4_fsblk_t bg_start;
406
	ext4_fsblk_t last_block;
407
	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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	last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;

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

/**
435
 *	ext4_find_goal - find a preferred place for allocation.
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 *	@inode: owner
 *	@block:  block we want
 *	@partial: pointer to the last triple within a chain
 *
440
 *	Normally this function find the preferred place for block allocation,
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 *	returns it.
442
 */
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static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
444
		Indirect *partial)
445
{
446
	struct ext4_block_alloc_info *block_i;
447

448
	block_i =  EXT4_I(inode)->i_block_alloc_info;
449 450 451 452 453 454 455 456 457 458

	/*
	 * 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;
	}

459
	return ext4_find_near(inode, partial);
460 461 462
}

/**
463
 *	ext4_blks_to_allocate: Look up the block map and count the number
464 465 466 467 468 469 470 471 472 473
 *	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.
 */
474
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;
}

/**
501
 *	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
 */
510
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
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				ext4_lblk_t iblock, ext4_fsblk_t goal,
				int indirect_blks, int blks,
				ext4_fsblk_t new_blocks[4], int *err)
514 515
{
	int target, i;
516
	unsigned long count = 0, blk_allocated = 0;
517
	int index = 0;
518
	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)
	 */
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	/* first we try to allocate the indirect blocks */
	target = indirect_blks;
	while (target > 0) {
532 533
		count = target;
		/* allocating blocks for indirect blocks and direct blocks */
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		current_block = ext4_new_meta_blocks(handle, inode,
							goal, &count, err);
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		if (*err)
			goto failed_out;

		target -= count;
		/* allocate blocks for indirect blocks */
		while (index < indirect_blks && count) {
			new_blocks[index++] = current_block++;
			count--;
		}
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		if (count > 0) {
			/*
			 * save the new block number
			 * for the first direct block
			 */
			new_blocks[index] = current_block;
			printk(KERN_INFO "%s returned more blocks than "
						"requested\n", __func__);
			WARN_ON(1);
554
			break;
555
		}
556 557
	}

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	target = blks - count ;
	blk_allocated = count;
	if (!target)
		goto allocated;
	/* Now allocate data blocks */
	count = target;
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	/* allocating blocks for data blocks */
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	current_block = ext4_new_blocks(handle, inode, iblock,
						goal, &count, err);
	if (*err && (target == blks)) {
		/*
		 * if the allocation failed and we didn't allocate
		 * any blocks before
		 */
		goto failed_out;
	}
	if (!*err) {
		if (target == blks) {
		/*
		 * save the new block number
		 * for the first direct block
		 */
			new_blocks[index] = current_block;
		}
		blk_allocated += count;
	}
allocated:
585
	/* total number of blocks allocated for direct blocks */
586
	ret = blk_allocated;
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	*err = 0;
	return ret;
failed_out:
	for (i = 0; i <index; i++)
591
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
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	return ret;
}

/**
596
 *	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
607
 *	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
610
 *	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
617
 *	ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
618 619
 *	as described above and return 0.
 */
620
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
621 622 623
				ext4_lblk_t iblock, int indirect_blks,
				int *blks, ext4_fsblk_t goal,
				ext4_lblk_t *offsets, Indirect *branch)
624 625 626 627 628 629
{
	int blocksize = inode->i_sb->s_blocksize;
	int i, n = 0;
	int err = 0;
	struct buffer_head *bh;
	int num;
630 631
	ext4_fsblk_t new_blocks[4];
	ext4_fsblk_t current_block;
632

633
	num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651
				*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");
652
		err = ext4_journal_get_create_access(handle, bh);
653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676
		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);

677 678
		BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, bh);
679 680 681 682 683 684 685 686
		if (err)
			goto failed;
	}
	*blks = num;
	return err;
failed:
	/* Allocation failed, free what we already allocated */
	for (i = 1; i <= n ; i++) {
687
		BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
688
		ext4_journal_forget(handle, branch[i].bh);
689 690
	}
	for (i = 0; i <indirect_blks; i++)
691
		ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
692

693
	ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
694 695 696 697 698

	return err;
}

/**
699
 * ext4_splice_branch - splice the allocated branch onto inode.
700 701 702
 * @inode: owner
 * @block: (logical) number of block we are adding
 * @chain: chain of indirect blocks (with a missing link - see
703
 *	ext4_alloc_branch)
704 705 706 707 708 709 710 711
 * @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.
 */
712
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
713
			ext4_lblk_t block, Indirect *where, int num, int blks)
714 715 716
{
	int i;
	int err = 0;
717 718
	struct ext4_block_alloc_info *block_i;
	ext4_fsblk_t current_block;
719

720
	block_i = EXT4_I(inode)->i_block_alloc_info;
721 722 723 724 725 726 727
	/*
	 * 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");
728
		err = ext4_journal_get_write_access(handle, where->bh);
729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758
		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
759
	inode->i_ctime = ext4_current_time(inode);
760
	ext4_mark_inode_dirty(handle, inode);
761 762 763 764 765 766 767 768 769

	/* 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
770
		 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
771 772
		 */
		jbd_debug(5, "splicing indirect only\n");
773 774
		BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
		err = ext4_journal_dirty_metadata(handle, where->bh);
775 776 777 778 779 780 781 782 783 784 785 786 787
		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++) {
788
		BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
789
		ext4_journal_forget(handle, where[i].bh);
790 791
		ext4_free_blocks(handle, inode,
					le32_to_cpu(where[i-1].key), 1, 0);
792
	}
793
	ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814

	return err;
}

/*
 * Allocation strategy is simple: if we have to allocate something, we will
 * have to go the whole way to leaf. So let's do it before attaching anything
 * to tree, set linkage between the newborn blocks, write them if sync is
 * required, recheck the path, free and repeat if check fails, otherwise
 * set the last missing link (that will protect us from any truncate-generated
 * removals - all blocks on the path are immune now) and possibly force the
 * write on the parent block.
 * That has a nice additional property: no special recovery from the failed
 * allocations is needed - we simply release blocks and do not touch anything
 * reachable from inode.
 *
 * `handle' can be NULL if create == 0.
 *
 * return > 0, # of blocks mapped or allocated.
 * return = 0, if plain lookup failed.
 * return < 0, error case.
815 816 817
 *
 *
 * Need to be called with
818 819
 * 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)
820
 */
821
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
822
		ext4_lblk_t iblock, unsigned long maxblocks,
823 824 825 826
		struct buffer_head *bh_result,
		int create, int extend_disksize)
{
	int err = -EIO;
A
Aneesh Kumar K.V 已提交
827
	ext4_lblk_t offsets[4];
828 829
	Indirect chain[4];
	Indirect *partial;
830
	ext4_fsblk_t goal;
831 832 833
	int indirect_blks;
	int blocks_to_boundary = 0;
	int depth;
834
	struct ext4_inode_info *ei = EXT4_I(inode);
835
	int count = 0;
836
	ext4_fsblk_t first_block = 0;
837 838


A
Alex Tomas 已提交
839
	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
840
	J_ASSERT(handle != NULL || create == 0);
A
Aneesh Kumar K.V 已提交
841 842
	depth = ext4_block_to_path(inode, iblock, offsets,
					&blocks_to_boundary);
843 844 845 846

	if (depth == 0)
		goto out;

847
	partial = ext4_get_branch(inode, depth, offsets, chain, &err);
848 849 850 851 852 853 854 855

	/* 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) {
856
			ext4_fsblk_t blk;
857 858 859 860 861 862 863 864

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

			if (blk == first_block + count)
				count++;
			else
				break;
		}
865
		goto got_it;
866 867 868 869 870 871 872 873 874 875 876
	}

	/* 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))
877
		ext4_init_block_alloc_info(inode);
878

879
	goal = ext4_find_goal(inode, iblock, partial);
880 881 882 883 884 885 886 887

	/* 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.
	 */
888
	count = ext4_blks_to_allocate(partial, indirect_blks,
889 890
					maxblocks, blocks_to_boundary);
	/*
891
	 * Block out ext4_truncate while we alter the tree
892
	 */
893 894 895
	err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
					&count, goal,
					offsets + (partial - chain), partial);
896 897

	/*
898
	 * The ext4_splice_branch call will free and forget any buffers
899 900 901 902 903 904
	 * 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)
905
		err = ext4_splice_branch(handle, inode, iblock,
906 907
					partial, indirect_blks, count);
	/*
908
	 * i_disksize growing is protected by i_data_sem.  Don't forget to
909
	 * protect it if you're about to implement concurrent
910
	 * ext4_get_block() -bzzz
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935
	*/
	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;
}

J
Jan Kara 已提交
936 937 938 939 940 941 942 943 944 945
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
/*
 * Number of credits we need for writing DIO_MAX_BLOCKS:
 * We need sb + group descriptor + bitmap + inode -> 4
 * For B blocks with A block pointers per block we need:
 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
 */
#define DIO_CREDITS 25
946

947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970

/*
 *
 *
 * ext4_ext4 get_block() wrapper function
 * It will do a look up first, and returns if the blocks already mapped.
 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
 * and store the allocated blocks in the result buffer head and mark it
 * mapped.
 *
 * If file type is extents based, it will call ext4_ext_get_blocks(),
 * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
 * based files
 *
 * On success, it returns the number of blocks being mapped or allocate.
 * if create==0 and the blocks are pre-allocated and uninitialized block,
 * the result buffer head is unmapped. If the create ==1, it will make sure
 * the buffer head is mapped.
 *
 * It returns 0 if plain look up failed (blocks have not been allocated), in
 * that casem, buffer head is unmapped
 *
 * It returns the error in case of allocation failure.
 */
971 972 973 974 975
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;
976 977 978

	clear_buffer_mapped(bh);

979 980 981 982 983 984 985 986
	/*
	 * 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);
987
	} else {
988 989
		retval = ext4_get_blocks_handle(handle,
				inode, block, max_blocks, bh, 0, 0);
990
	}
991
	up_read((&EXT4_I(inode)->i_data_sem));
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004

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

	/*
	 * Returns if the blocks have already allocated
	 *
	 * Note that if blocks have been preallocated
	 * ext4_ext_get_block() returns th create = 0
	 * with buffer head unmapped.
	 */
	if (retval > 0 && buffer_mapped(bh))
1005 1006 1007
		return retval;

	/*
1008 1009 1010 1011
	 * New blocks allocate and/or writing to uninitialized extent
	 * will possibly result in updating i_data, so we take
	 * the write lock of i_data_sem, and call get_blocks()
	 * with create == 1 flag.
1012 1013 1014 1015 1016 1017
	 */
	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
	 */
1018 1019 1020 1021 1022 1023
	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);
1024 1025 1026 1027 1028 1029 1030 1031 1032 1033

		if (retval > 0 && buffer_new(bh)) {
			/*
			 * We allocated new blocks which will result in
			 * i_data's format changing.  Force the migrate
			 * to fail by clearing migrate flags
			 */
			EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
							~EXT4_EXT_MIGRATE;
		}
1034
	}
1035
	up_write((&EXT4_I(inode)->i_data_sem));
1036 1037 1038
	return retval;
}

1039
static int ext4_get_block(struct inode *inode, sector_t iblock,
1040 1041
			struct buffer_head *bh_result, int create)
{
1042
	handle_t *handle = ext4_journal_current_handle();
J
Jan Kara 已提交
1043
	int ret = 0, started = 0;
1044 1045
	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;

J
Jan Kara 已提交
1046 1047 1048 1049 1050 1051 1052
	if (create && !handle) {
		/* Direct IO write... */
		if (max_blocks > DIO_MAX_BLOCKS)
			max_blocks = DIO_MAX_BLOCKS;
		handle = ext4_journal_start(inode, DIO_CREDITS +
			      2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
		if (IS_ERR(handle)) {
1053
			ret = PTR_ERR(handle);
J
Jan Kara 已提交
1054
			goto out;
1055
		}
J
Jan Kara 已提交
1056
		started = 1;
1057 1058
	}

J
Jan Kara 已提交
1059
	ret = ext4_get_blocks_wrap(handle, inode, iblock,
1060
					max_blocks, bh_result, create, 0);
J
Jan Kara 已提交
1061 1062 1063
	if (ret > 0) {
		bh_result->b_size = (ret << inode->i_blkbits);
		ret = 0;
1064
	}
J
Jan Kara 已提交
1065 1066 1067
	if (started)
		ext4_journal_stop(handle);
out:
1068 1069 1070 1071 1072 1073
	return ret;
}

/*
 * `handle' can be NULL if create is zero
 */
1074
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1075
				ext4_lblk_t block, int create, int *errp)
1076 1077 1078 1079 1080 1081 1082 1083 1084
{
	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
1085
	err = ext4_get_blocks_wrap(handle, inode, block, 1,
1086 1087
					&dummy, create, 1);
	/*
1088
	 * ext4_get_blocks_handle() returns number of blocks
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
	 * 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
1106
			J_ASSERT(handle != NULL);
1107 1108 1109 1110 1111

			/*
			 * 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
1112
			 * writes use ext4_get_block instead, so it's not a
1113 1114 1115 1116
			 * problem.
			 */
			lock_buffer(bh);
			BUFFER_TRACE(bh, "call get_create_access");
1117
			fatal = ext4_journal_get_create_access(handle, bh);
1118 1119 1120 1121 1122
			if (!fatal && !buffer_uptodate(bh)) {
				memset(bh->b_data,0,inode->i_sb->s_blocksize);
				set_buffer_uptodate(bh);
			}
			unlock_buffer(bh);
1123 1124
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			err = ext4_journal_dirty_metadata(handle, bh);
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
			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;
}

1141
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
A
Aneesh Kumar K.V 已提交
1142
			       ext4_lblk_t block, int create, int *err)
1143 1144 1145
{
	struct buffer_head * bh;

1146
	bh = ext4_getblk(handle, inode, block, create, err);
1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
	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
1195
 * close off a transaction and start a new one between the ext4_get_block()
1196
 * and the commit_write().  So doing the jbd2_journal_start at the start of
1197 1198
 * prepare_write() is the right place.
 *
1199 1200
 * Also, this function can nest inside ext4_writepage() ->
 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1201 1202 1203 1204
 * 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.
 *
1205
 * By accident, ext4 can be reentered when a transaction is open via
1206 1207 1208 1209 1210 1211
 * 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.
 *
1212
 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1213 1214 1215 1216 1217 1218 1219 1220 1221
 * 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;
1222
	return ext4_journal_get_write_access(handle, bh);
1223 1224
}

N
Nick Piggin 已提交
1225 1226 1227
static int ext4_write_begin(struct file *file, struct address_space *mapping,
				loff_t pos, unsigned len, unsigned flags,
				struct page **pagep, void **fsdata)
1228
{
N
Nick Piggin 已提交
1229
 	struct inode *inode = mapping->host;
1230
	int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1231 1232
	handle_t *handle;
	int retries = 0;
N
Nick Piggin 已提交
1233 1234 1235 1236 1237 1238 1239
 	struct page *page;
 	pgoff_t index;
 	unsigned from, to;

 	index = pos >> PAGE_CACHE_SHIFT;
 	from = pos & (PAGE_CACHE_SIZE - 1);
 	to = from + len;
1240 1241

retry:
N
Nick Piggin 已提交
1242 1243 1244 1245
  	handle = ext4_journal_start(inode, needed_blocks);
  	if (IS_ERR(handle)) {
  		ret = PTR_ERR(handle);
  		goto out;
1246
	}
1247

1248 1249 1250 1251 1252 1253 1254 1255
	page = __grab_cache_page(mapping, index);
	if (!page) {
		ext4_journal_stop(handle);
		ret = -ENOMEM;
		goto out;
	}
	*pagep = page;

N
Nick Piggin 已提交
1256 1257 1258 1259
	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
							ext4_get_block);

	if (!ret && ext4_should_journal_data(inode)) {
1260 1261 1262
		ret = walk_page_buffers(handle, page_buffers(page),
				from, to, NULL, do_journal_get_write_access);
	}
N
Nick Piggin 已提交
1263 1264 1265

	if (ret) {
 		unlock_page(page);
1266
		ext4_journal_stop(handle);
N
Nick Piggin 已提交
1267 1268 1269
 		page_cache_release(page);
	}

1270
	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1271
		goto retry;
1272
out:
1273 1274 1275
	return ret;
}

1276
int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1277
{
1278
	int err = jbd2_journal_dirty_data(handle, bh);
1279
	if (err)
1280
		ext4_journal_abort_handle(__func__, __func__,
N
Nick Piggin 已提交
1281
						bh, handle, err);
1282 1283 1284
	return err;
}

N
Nick Piggin 已提交
1285 1286
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1287 1288 1289 1290
{
	if (!buffer_mapped(bh) || buffer_freed(bh))
		return 0;
	set_buffer_uptodate(bh);
1291
	return ext4_journal_dirty_metadata(handle, bh);
1292 1293 1294 1295 1296 1297
}

/*
 * 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().
 *
1298
 * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1299 1300
 * buffers are managed internally.
 */
N
Nick Piggin 已提交
1301 1302 1303 1304
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)
1305
{
1306
	handle_t *handle = ext4_journal_current_handle();
1307
	struct inode *inode = mapping->host;
N
Nick Piggin 已提交
1308
	unsigned from, to;
1309 1310
	int ret = 0, ret2;

N
Nick Piggin 已提交
1311 1312 1313
	from = pos & (PAGE_CACHE_SIZE - 1);
	to = from + len;

1314
	ret = walk_page_buffers(handle, page_buffers(page),
1315
		from, to, NULL, ext4_journal_dirty_data);
1316 1317 1318

	if (ret == 0) {
		/*
N
Nick Piggin 已提交
1319
		 * generic_write_end() will run mark_inode_dirty() if i_size
1320 1321 1322 1323 1324
		 * changes.  So let's piggyback the i_disksize mark_inode_dirty
		 * into that.
		 */
		loff_t new_i_size;

N
Nick Piggin 已提交
1325
		new_i_size = pos + copied;
1326 1327
		if (new_i_size > EXT4_I(inode)->i_disksize)
			EXT4_I(inode)->i_disksize = new_i_size;
1328
		ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1329
							page, fsdata);
1330 1331 1332
		copied = ret2;
		if (ret2 < 0)
			ret = ret2;
1333
	}
1334
	ret2 = ext4_journal_stop(handle);
1335 1336
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1337 1338

	return ret ? ret : copied;
1339 1340
}

N
Nick Piggin 已提交
1341 1342 1343 1344
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)
1345
{
1346
	handle_t *handle = ext4_journal_current_handle();
1347
	struct inode *inode = mapping->host;
1348 1349 1350
	int ret = 0, ret2;
	loff_t new_i_size;

N
Nick Piggin 已提交
1351
	new_i_size = pos + copied;
1352 1353
	if (new_i_size > EXT4_I(inode)->i_disksize)
		EXT4_I(inode)->i_disksize = new_i_size;
1354

1355
	ret2 = generic_write_end(file, mapping, pos, len, copied,
N
Nick Piggin 已提交
1356
							page, fsdata);
1357 1358 1359
	copied = ret2;
	if (ret2 < 0)
		ret = ret2;
1360

1361
	ret2 = ext4_journal_stop(handle);
1362 1363
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1364 1365

	return ret ? ret : copied;
1366 1367
}

N
Nick Piggin 已提交
1368 1369 1370 1371
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)
1372
{
1373
	handle_t *handle = ext4_journal_current_handle();
N
Nick Piggin 已提交
1374
	struct inode *inode = mapping->host;
1375 1376
	int ret = 0, ret2;
	int partial = 0;
N
Nick Piggin 已提交
1377
	unsigned from, to;
1378

N
Nick Piggin 已提交
1379 1380 1381 1382 1383 1384 1385 1386
	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);
	}
1387 1388

	ret = walk_page_buffers(handle, page_buffers(page), from,
N
Nick Piggin 已提交
1389
				to, &partial, write_end_fn);
1390 1391
	if (!partial)
		SetPageUptodate(page);
N
Nick Piggin 已提交
1392 1393
	if (pos+copied > inode->i_size)
		i_size_write(inode, pos+copied);
1394 1395 1396 1397
	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);
1398 1399 1400
		if (!ret)
			ret = ret2;
	}
N
Nick Piggin 已提交
1401

1402
	unlock_page(page);
1403
	ret2 = ext4_journal_stop(handle);
1404 1405
	if (!ret)
		ret = ret2;
N
Nick Piggin 已提交
1406 1407 1408
	page_cache_release(page);

	return ret ? ret : copied;
1409 1410 1411 1412 1413 1414 1415
}

/*
 * 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
1416
 * journal.  If somebody makes a swapfile on an ext4 data-journaling
1417 1418 1419 1420 1421 1422 1423 1424
 * 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.
 */
1425
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
1426 1427 1428 1429 1430
{
	struct inode *inode = mapping->host;
	journal_t *journal;
	int err;

1431
	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442
		/*
		 * 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.)
		 *
1443
		 * NB. EXT4_STATE_JDATA is not set on files other than
1444 1445 1446 1447 1448 1449
		 * 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.
		 */

1450 1451
		EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
		journal = EXT4_JOURNAL(inode);
1452 1453 1454
		jbd2_journal_lock_updates(journal);
		err = jbd2_journal_flush(journal);
		jbd2_journal_unlock_updates(journal);
1455 1456 1457 1458 1459

		if (err)
			return 0;
	}

1460
	return generic_block_bmap(mapping,block,ext4_get_block);
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474
}

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;
}

1475
static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1476 1477
{
	if (buffer_mapped(bh))
1478
		return ext4_journal_dirty_data(handle, bh);
1479 1480 1481
	return 0;
}

1482 1483 1484 1485 1486
static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
{
	return !buffer_mapped(bh) || buffer_delay(bh);
}

1487
/*
1488 1489 1490 1491
 * Note that we don't need to start a transaction unless we're journaling
 * data because we should have holes filled from ext4_page_mkwrite(). If
 * we are journaling data, we cannot start transaction directly because
 * transaction start ranks above page lock so we have to do some magic...
1492 1493 1494 1495 1496
 *
 * In all journalling modes block_write_full_page() will start the I/O.
 *
 * Problem:
 *
1497 1498
 *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
 *		ext4_writepage()
1499 1500 1501
 *
 * Similar for:
 *
1502
 *	ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1503
 *
1504
 * Same applies to ext4_get_block().  We will deadlock on various things like
1505
 * lock_journal and i_data_sem
1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535
 *
 * 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.
 *
 */
1536
static int __ext4_ordered_writepage(struct page *page,
1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct buffer_head *page_bufs;
	handle_t *handle = NULL;
	int ret = 0;
	int err;

	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);

1553
	ret = block_write_full_page(page, ext4_get_block, wbc);
1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567

	/*
	 * 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) {
1568 1569 1570 1571 1572 1573 1574 1575
		handle = ext4_journal_start(inode,
					ext4_writepage_trans_blocks(inode));
		if (IS_ERR(handle)) {
			ret = PTR_ERR(handle);
			goto out_put;
		}

		ret = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1576
					NULL, jbd2_journal_dirty_data_fn);
1577
		err = ext4_journal_stop(handle);
1578 1579 1580
		if (!ret)
			ret = err;
	}
1581 1582 1583
out_put:
	walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
			  bput_one);
1584
	return ret;
1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608
}

static int ext4_ordered_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	loff_t size = i_size_read(inode);
	loff_t len;

	J_ASSERT(PageLocked(page));
	J_ASSERT(page_has_buffers(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
	BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
				 ext4_bh_unmapped_or_delay));

	/*
	 * We give up here if we're reentered, because it might be for a
	 * different filesystem.
	 */
	if (!ext4_journal_current_handle())
		return __ext4_ordered_writepage(page, wbc);
1609 1610 1611

	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
1612
	return 0;
1613 1614
}

1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
static int __ext4_writeback_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;

	if (test_opt(inode->i_sb, NOBH))
		return nobh_writepage(page, ext4_get_block, wbc);
	else
		return block_write_full_page(page, ext4_get_block, wbc);
}


1627
static int ext4_writeback_writepage(struct page *page,
1628 1629 1630
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656
	loff_t size = i_size_read(inode);
	loff_t len;

	J_ASSERT(PageLocked(page));
	J_ASSERT(page_has_buffers(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
	BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
				 ext4_bh_unmapped_or_delay));

	if (!ext4_journal_current_handle())
		return __ext4_writeback_writepage(page, wbc);

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

static int __ext4_journalled_writepage(struct page *page,
				struct writeback_control *wbc)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode = mapping->host;
	struct buffer_head *page_bufs;
1657 1658 1659 1660
	handle_t *handle = NULL;
	int ret = 0;
	int err;

1661 1662 1663 1664 1665 1666 1667 1668 1669 1670
	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE, ext4_get_block);
	if (ret != 0)
		goto out_unlock;

	page_bufs = page_buffers(page);
	walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
								bget_one);
	/* As soon as we unlock the page, it can go away, but we have
	 * references to buffers so we are safe */
	unlock_page(page);
1671

1672
	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1673 1674
	if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
1675
		goto out;
1676 1677
	}

1678 1679
	ret = walk_page_buffers(handle, page_bufs, 0,
			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1680

1681 1682 1683 1684
	err = walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, write_end_fn);
	if (ret == 0)
		ret = err;
1685
	err = ext4_journal_stop(handle);
1686 1687 1688
	if (!ret)
		ret = err;

1689 1690 1691 1692 1693 1694
	walk_page_buffers(handle, page_bufs, 0,
				PAGE_CACHE_SIZE, NULL, bput_one);
	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
	goto out;

out_unlock:
1695
	unlock_page(page);
1696
out:
1697 1698 1699
	return ret;
}

1700
static int ext4_journalled_writepage(struct page *page,
1701 1702 1703
				struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
1704 1705
	loff_t size = i_size_read(inode);
	loff_t len;
1706

1707 1708 1709 1710 1711 1712 1713 1714
	J_ASSERT(PageLocked(page));
	J_ASSERT(page_has_buffers(page));
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;
	BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
				 ext4_bh_unmapped_or_delay));
1715

1716
	if (ext4_journal_current_handle())
1717 1718
		goto no_write;

1719
	if (PageChecked(page)) {
1720 1721 1722 1723 1724
		/*
		 * It's mmapped pagecache.  Add buffers and journal it.  There
		 * doesn't seem much point in redirtying the page here.
		 */
		ClearPageChecked(page);
1725
		return __ext4_journalled_writepage(page, wbc);
1726 1727 1728 1729 1730 1731
	} 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.
		 */
1732
		return block_write_full_page(page, ext4_get_block, wbc);
1733 1734 1735 1736
	}
no_write:
	redirty_page_for_writepage(wbc, page);
	unlock_page(page);
1737
	return 0;
1738 1739
}

1740
static int ext4_readpage(struct file *file, struct page *page)
1741
{
1742
	return mpage_readpage(page, ext4_get_block);
1743 1744 1745
}

static int
1746
ext4_readpages(struct file *file, struct address_space *mapping,
1747 1748
		struct list_head *pages, unsigned nr_pages)
{
1749
	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
1750 1751
}

1752
static void ext4_invalidatepage(struct page *page, unsigned long offset)
1753
{
1754
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1755 1756 1757 1758 1759 1760 1761

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

1762
	jbd2_journal_invalidatepage(journal, page, offset);
1763 1764
}

1765
static int ext4_releasepage(struct page *page, gfp_t wait)
1766
{
1767
	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
1768 1769 1770 1771

	WARN_ON(PageChecked(page));
	if (!page_has_buffers(page))
		return 0;
1772
	return jbd2_journal_try_to_free_buffers(journal, page, wait);
1773 1774 1775 1776 1777 1778 1779 1780
}

/*
 * If the O_DIRECT write will extend the file then add this inode to the
 * orphan list.  So recovery will truncate it back to the original size
 * if the machine crashes during the write.
 *
 * If the O_DIRECT write is intantiating holes inside i_size and the machine
J
Jan Kara 已提交
1781 1782
 * crashes then stale disk data _may_ be exposed inside the file. But current
 * VFS code falls back into buffered path in that case so we are safe.
1783
 */
1784
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
1785 1786 1787 1788 1789
			const struct iovec *iov, loff_t offset,
			unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;
1790
	struct ext4_inode_info *ei = EXT4_I(inode);
J
Jan Kara 已提交
1791
	handle_t *handle;
1792 1793 1794 1795 1796 1797 1798 1799
	ssize_t ret;
	int orphan = 0;
	size_t count = iov_length(iov, nr_segs);

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

		if (final_size > inode->i_size) {
J
Jan Kara 已提交
1800 1801 1802 1803 1804 1805
			/* Credits for sb + inode write */
			handle = ext4_journal_start(inode, 2);
			if (IS_ERR(handle)) {
				ret = PTR_ERR(handle);
				goto out;
			}
1806
			ret = ext4_orphan_add(handle, inode);
J
Jan Kara 已提交
1807 1808 1809 1810
			if (ret) {
				ext4_journal_stop(handle);
				goto out;
			}
1811 1812
			orphan = 1;
			ei->i_disksize = inode->i_size;
J
Jan Kara 已提交
1813
			ext4_journal_stop(handle);
1814 1815 1816 1817 1818
		}
	}

	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
				 offset, nr_segs,
1819
				 ext4_get_block, NULL);
1820

J
Jan Kara 已提交
1821
	if (orphan) {
1822 1823
		int err;

J
Jan Kara 已提交
1824 1825 1826 1827 1828 1829 1830 1831 1832 1833
		/* Credits for sb + inode write */
		handle = ext4_journal_start(inode, 2);
		if (IS_ERR(handle)) {
			/* This is really bad luck. We've written the data
			 * but cannot extend i_size. Bail out and pretend
			 * the write failed... */
			ret = PTR_ERR(handle);
			goto out;
		}
		if (inode->i_nlink)
1834
			ext4_orphan_del(handle, inode);
J
Jan Kara 已提交
1835
		if (ret > 0) {
1836 1837 1838 1839 1840 1841 1842 1843
			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
1844
				 * ext4_mark_inode_dirty() to userspace.  So
1845 1846
				 * ignore it.
				 */
1847
				ext4_mark_inode_dirty(handle, inode);
1848 1849
			}
		}
1850
		err = ext4_journal_stop(handle);
1851 1852 1853 1854 1855 1856 1857 1858
		if (ret == 0)
			ret = err;
	}
out:
	return ret;
}

/*
1859
 * Pages can be marked dirty completely asynchronously from ext4's journalling
1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870
 * 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.
 */
1871
static int ext4_journalled_set_page_dirty(struct page *page)
1872 1873 1874 1875 1876
{
	SetPageChecked(page);
	return __set_page_dirty_nobuffers(page);
}

1877 1878 1879 1880
static const struct address_space_operations ext4_ordered_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_ordered_writepage,
1881
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1882 1883
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_ordered_write_end,
1884 1885 1886 1887
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1888 1889 1890
	.migratepage	= buffer_migrate_page,
};

1891 1892 1893 1894
static const struct address_space_operations ext4_writeback_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_writeback_writepage,
1895
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1896 1897
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_writeback_write_end,
1898 1899 1900 1901
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
	.direct_IO	= ext4_direct_IO,
1902 1903 1904
	.migratepage	= buffer_migrate_page,
};

1905 1906 1907 1908
static const struct address_space_operations ext4_journalled_aops = {
	.readpage	= ext4_readpage,
	.readpages	= ext4_readpages,
	.writepage	= ext4_journalled_writepage,
1909
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1910 1911
	.write_begin	= ext4_write_begin,
	.write_end	= ext4_journalled_write_end,
1912 1913 1914 1915
	.set_page_dirty	= ext4_journalled_set_page_dirty,
	.bmap		= ext4_bmap,
	.invalidatepage	= ext4_invalidatepage,
	.releasepage	= ext4_releasepage,
1916 1917
};

1918
void ext4_set_aops(struct inode *inode)
1919
{
1920 1921 1922 1923
	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;
1924
	else
1925
		inode->i_mapping->a_ops = &ext4_journalled_aops;
1926 1927 1928
}

/*
1929
 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
1930 1931 1932 1933
 * 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.
 */
1934
int ext4_block_truncate_page(handle_t *handle,
1935 1936
		struct address_space *mapping, loff_t from)
{
1937
	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1938
	unsigned offset = from & (PAGE_CACHE_SIZE-1);
A
Aneesh Kumar K.V 已提交
1939 1940
	unsigned blocksize, length, pos;
	ext4_lblk_t iblock;
1941 1942
	struct inode *inode = mapping->host;
	struct buffer_head *bh;
1943
	struct page *page;
1944 1945
	int err = 0;

1946 1947 1948 1949
	page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
	if (!page)
		return -EINVAL;

1950 1951 1952 1953 1954 1955 1956 1957 1958
	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) &&
1959
	     ext4_should_writeback_data(inode) && PageUptodate(page)) {
1960
		zero_user(page, offset, length);
1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984
		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");
1985
		ext4_get_block(inode, iblock, bh, 0);
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
		/* 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;
	}

2006
	if (ext4_should_journal_data(inode)) {
2007
		BUFFER_TRACE(bh, "get write access");
2008
		err = ext4_journal_get_write_access(handle, bh);
2009 2010 2011 2012
		if (err)
			goto unlock;
	}

2013
	zero_user(page, offset, length);
2014 2015 2016 2017

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

	err = 0;
2018 2019
	if (ext4_should_journal_data(inode)) {
		err = ext4_journal_dirty_metadata(handle, bh);
2020
	} else {
2021 2022
		if (ext4_should_order_data(inode))
			err = ext4_journal_dirty_data(handle, bh);
2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
		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;
}

/**
2046
 *	ext4_find_shared - find the indirect blocks for partial truncation.
2047 2048
 *	@inode:	  inode in question
 *	@depth:	  depth of the affected branch
2049
 *	@offsets: offsets of pointers in that branch (see ext4_block_to_path)
2050 2051 2052
 *	@chain:	  place to store the pointers to partial indirect blocks
 *	@top:	  place to the (detached) top of branch
 *
2053
 *	This is a helper function used by ext4_truncate().
2054 2055 2056 2057 2058 2059 2060
 *
 *	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
2061
 *	past the truncation point is possible until ext4_truncate()
2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079
 *	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).  */

2080
static Indirect *ext4_find_shared(struct inode *inode, int depth,
A
Aneesh Kumar K.V 已提交
2081
			ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
2082 2083 2084 2085 2086 2087 2088 2089
{
	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--)
		;
2090
	partial = ext4_get_branch(inode, k, offsets, chain, &err);
2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112
	/* 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;
2113
		/* Nope, don't do this in ext4.  Must leave the tree intact */
2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135
#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.
 */
2136 2137
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
		struct buffer_head *bh, ext4_fsblk_t block_to_free,
2138 2139 2140 2141 2142
		unsigned long count, __le32 *first, __le32 *last)
{
	__le32 *p;
	if (try_to_extend_transaction(handle, inode)) {
		if (bh) {
2143 2144
			BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
			ext4_journal_dirty_metadata(handle, bh);
2145
		}
2146 2147
		ext4_mark_inode_dirty(handle, inode);
		ext4_journal_test_restart(handle, inode);
2148 2149
		if (bh) {
			BUFFER_TRACE(bh, "retaking write access");
2150
			ext4_journal_get_write_access(handle, bh);
2151 2152 2153 2154 2155
		}
	}

	/*
	 * Any buffers which are on the journal will be in memory. We find
2156
	 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
2157
	 * on them.  We've already detached each block from the file, so
2158
	 * bforget() in jbd2_journal_forget() should be safe.
2159
	 *
2160
	 * AKPM: turn on bforget in jbd2_journal_forget()!!!
2161 2162 2163 2164
	 */
	for (p = first; p < last; p++) {
		u32 nr = le32_to_cpu(*p);
		if (nr) {
A
Aneesh Kumar K.V 已提交
2165
			struct buffer_head *tbh;
2166 2167

			*p = 0;
A
Aneesh Kumar K.V 已提交
2168 2169
			tbh = sb_find_get_block(inode->i_sb, nr);
			ext4_forget(handle, 0, inode, tbh, nr);
2170 2171 2172
		}
	}

2173
	ext4_free_blocks(handle, inode, block_to_free, count, 0);
2174 2175 2176
}

/**
2177
 * ext4_free_data - free a list of data blocks
2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194
 * @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.
 */
2195
static void ext4_free_data(handle_t *handle, struct inode *inode,
2196 2197 2198
			   struct buffer_head *this_bh,
			   __le32 *first, __le32 *last)
{
2199
	ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2200 2201 2202 2203
	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 */
2204
	ext4_fsblk_t nr;		    /* Current block # */
2205 2206 2207 2208 2209 2210
	__le32 *p;			    /* Pointer into inode/ind
					       for current block */
	int err;

	if (this_bh) {				/* For indirect block */
		BUFFER_TRACE(this_bh, "get_write_access");
2211
		err = ext4_journal_get_write_access(handle, this_bh);
2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228
		/* 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 {
2229
				ext4_clear_blocks(handle, inode, this_bh,
2230 2231 2232 2233 2234 2235 2236 2237 2238 2239
						  block_to_free,
						  count, block_to_free_p, p);
				block_to_free = nr;
				block_to_free_p = p;
				count = 1;
			}
		}
	}

	if (count > 0)
2240
		ext4_clear_blocks(handle, inode, this_bh, block_to_free,
2241 2242 2243
				  count, block_to_free_p, p);

	if (this_bh) {
2244
		BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259

		/*
		 * The buffer head should have an attached journal head at this
		 * point. However, if the data is corrupted and an indirect
		 * block pointed to itself, it would have been detached when
		 * the block was cleared. Check for this instead of OOPSing.
		 */
		if (bh2jh(this_bh))
			ext4_journal_dirty_metadata(handle, this_bh);
		else
			ext4_error(inode->i_sb, __func__,
				   "circular indirect block detected, "
				   "inode=%lu, block=%llu",
				   inode->i_ino,
				   (unsigned long long) this_bh->b_blocknr);
2260 2261 2262 2263
	}
}

/**
2264
 *	ext4_free_branches - free an array of branches
2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275
 *	@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.
 */
2276
static void ext4_free_branches(handle_t *handle, struct inode *inode,
2277 2278 2279
			       struct buffer_head *parent_bh,
			       __le32 *first, __le32 *last, int depth)
{
2280
	ext4_fsblk_t nr;
2281 2282 2283 2284 2285 2286 2287
	__le32 *p;

	if (is_handle_aborted(handle))
		return;

	if (depth--) {
		struct buffer_head *bh;
2288
		int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302
		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) {
2303
				ext4_error(inode->i_sb, "ext4_free_branches",
2304
					   "Read failure, inode=%lu, block=%llu",
2305 2306 2307 2308 2309 2310
					   inode->i_ino, nr);
				continue;
			}

			/* This zaps the entire block.  Bottom up. */
			BUFFER_TRACE(bh, "free child branches");
2311
			ext4_free_branches(handle, inode, bh,
2312 2313 2314 2315 2316 2317 2318 2319
					   (__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
2320
			 * jbd2_journal_revoke().
2321 2322 2323
			 *
			 * That's easy if it's exclusively part of this
			 * transaction.  But if it's part of the committing
2324
			 * transaction then jbd2_journal_forget() will simply
2325
			 * brelse() it.  That means that if the underlying
2326
			 * block is reallocated in ext4_get_block(),
2327 2328 2329 2330 2331 2332 2333 2334
			 * 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.
			 */
2335
			ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355

			/*
			 * 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)) {
2356 2357
				ext4_mark_inode_dirty(handle, inode);
				ext4_journal_test_restart(handle, inode);
2358 2359
			}

2360
			ext4_free_blocks(handle, inode, nr, 1, 1);
2361 2362 2363 2364 2365 2366 2367

			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");
2368
				if (!ext4_journal_get_write_access(handle,
2369 2370 2371
								   parent_bh)){
					*p = 0;
					BUFFER_TRACE(parent_bh,
2372 2373
					"call ext4_journal_dirty_metadata");
					ext4_journal_dirty_metadata(handle,
2374 2375 2376 2377 2378 2379 2380
								    parent_bh);
				}
			}
		}
	} else {
		/* We have reached the bottom of the tree. */
		BUFFER_TRACE(parent_bh, "free data blocks");
2381
		ext4_free_data(handle, inode, parent_bh, first, last);
2382 2383 2384
	}
}

2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397
int ext4_can_truncate(struct inode *inode)
{
	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
		return 0;
	if (S_ISREG(inode->i_mode))
		return 1;
	if (S_ISDIR(inode->i_mode))
		return 1;
	if (S_ISLNK(inode->i_mode))
		return !ext4_inode_is_fast_symlink(inode);
	return 0;
}

2398
/*
2399
 * ext4_truncate()
2400
 *
2401 2402
 * We block out ext4_get_block() block instantiations across the entire
 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418
 * 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
2419
 * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
2420
 * that this inode's truncate did not complete and it will again call
2421 2422
 * 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
2423
 * that's fine - as long as they are linked from the inode, the post-crash
2424
 * ext4_truncate() run will find them and release them.
2425
 */
2426
void ext4_truncate(struct inode *inode)
2427 2428
{
	handle_t *handle;
2429
	struct ext4_inode_info *ei = EXT4_I(inode);
2430
	__le32 *i_data = ei->i_data;
2431
	int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
2432
	struct address_space *mapping = inode->i_mapping;
A
Aneesh Kumar K.V 已提交
2433
	ext4_lblk_t offsets[4];
2434 2435 2436 2437
	Indirect chain[4];
	Indirect *partial;
	__le32 nr = 0;
	int n;
A
Aneesh Kumar K.V 已提交
2438
	ext4_lblk_t last_block;
2439 2440
	unsigned blocksize = inode->i_sb->s_blocksize;

2441
	if (!ext4_can_truncate(inode))
2442 2443
		return;

A
Aneesh Kumar K.V 已提交
2444
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
2445
		ext4_ext_truncate(inode);
A
Aneesh Kumar K.V 已提交
2446 2447
		return;
	}
A
Alex Tomas 已提交
2448

2449
	handle = start_transaction(inode);
2450
	if (IS_ERR(handle))
2451 2452 2453
		return;		/* AKPM: return what? */

	last_block = (inode->i_size + blocksize-1)
2454
					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
2455

2456 2457 2458
	if (inode->i_size & (blocksize - 1))
		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
			goto out_stop;
2459

2460
	n = ext4_block_to_path(inode, last_block, offsets, NULL);
2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472
	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.
	 */
2473
	if (ext4_orphan_add(handle, inode))
2474 2475 2476 2477 2478 2479 2480
		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
2481
	 * ext4 *really* writes onto the disk inode.
2482 2483 2484 2485
	 */
	ei->i_disksize = inode->i_size;

	/*
2486
	 * From here we block out all ext4_get_block() callers who want to
2487 2488
	 * modify the block allocation tree.
	 */
2489
	down_write(&ei->i_data_sem);
2490 2491

	if (n == 1) {		/* direct blocks */
2492 2493
		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
			       i_data + EXT4_NDIR_BLOCKS);
2494 2495 2496
		goto do_indirects;
	}

2497
	partial = ext4_find_shared(inode, n, offsets, chain, &nr);
2498 2499 2500 2501
	/* Kill the top of shared branch (not detached) */
	if (nr) {
		if (partial == chain) {
			/* Shared branch grows from the inode */
2502
			ext4_free_branches(handle, inode, NULL,
2503 2504 2505 2506 2507 2508 2509 2510 2511
					   &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");
2512
			ext4_free_branches(handle, inode, partial->bh,
2513 2514 2515 2516 2517 2518
					partial->p,
					partial->p+1, (chain+n-1) - partial);
		}
	}
	/* Clear the ends of indirect blocks on the shared branch */
	while (partial > chain) {
2519
		ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
2520 2521 2522 2523 2524 2525 2526 2527 2528 2529
				   (__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:
2530
		nr = i_data[EXT4_IND_BLOCK];
2531
		if (nr) {
2532 2533
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
			i_data[EXT4_IND_BLOCK] = 0;
2534
		}
2535 2536
	case EXT4_IND_BLOCK:
		nr = i_data[EXT4_DIND_BLOCK];
2537
		if (nr) {
2538 2539
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
			i_data[EXT4_DIND_BLOCK] = 0;
2540
		}
2541 2542
	case EXT4_DIND_BLOCK:
		nr = i_data[EXT4_TIND_BLOCK];
2543
		if (nr) {
2544 2545
			ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
			i_data[EXT4_TIND_BLOCK] = 0;
2546
		}
2547
	case EXT4_TIND_BLOCK:
2548 2549 2550
		;
	}

2551
	ext4_discard_reservation(inode);
2552

2553
	up_write(&ei->i_data_sem);
K
Kalpak Shah 已提交
2554
	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
2555
	ext4_mark_inode_dirty(handle, inode);
2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567

	/*
	 * 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
2568
	 * ext4_delete_inode(), and we allow that function to clean up the
2569 2570 2571
	 * orphan info for us.
	 */
	if (inode->i_nlink)
2572
		ext4_orphan_del(handle, inode);
2573

2574
	ext4_journal_stop(handle);
2575 2576
}

2577 2578
static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
		unsigned long ino, struct ext4_iloc *iloc)
2579
{
2580
	ext4_group_t block_group;
2581
	unsigned long offset;
2582
	ext4_fsblk_t block;
A
Akinobu Mita 已提交
2583
	struct ext4_group_desc *gdp;
2584

2585
	if (!ext4_valid_inum(sb, ino)) {
2586 2587 2588 2589 2590 2591 2592 2593
		/*
		 * 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;
	}

2594
	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
A
Akinobu Mita 已提交
2595 2596
	gdp = ext4_get_group_desc(sb, block_group, NULL);
	if (!gdp)
2597 2598 2599 2600 2601
		return 0;

	/*
	 * Figure out the offset within the block group inode table
	 */
2602 2603
	offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
		EXT4_INODE_SIZE(sb);
2604 2605
	block = ext4_inode_table(sb, gdp) +
		(offset >> EXT4_BLOCK_SIZE_BITS(sb));
2606 2607

	iloc->block_group = block_group;
2608
	iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
2609 2610 2611 2612
	return block;
}

/*
2613
 * ext4_get_inode_loc returns with an extra refcount against the inode's
2614 2615 2616 2617
 * 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.
 */
2618 2619
static int __ext4_get_inode_loc(struct inode *inode,
				struct ext4_iloc *iloc, int in_mem)
2620
{
2621
	ext4_fsblk_t block;
2622 2623
	struct buffer_head *bh;

2624
	block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2625 2626 2627 2628 2629
	if (!block)
		return -EIO;

	bh = sb_getblk(inode->i_sb, block);
	if (!bh) {
2630
		ext4_error (inode->i_sb, "ext4_get_inode_loc",
2631
				"unable to read inode block - "
2632
				"inode=%lu, block=%llu",
2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650
				 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;
2651
			struct ext4_group_desc *desc;
2652 2653
			int inodes_per_buffer;
			int inode_offset, i;
2654
			ext4_group_t block_group;
2655 2656 2657
			int start;

			block_group = (inode->i_ino - 1) /
2658
					EXT4_INODES_PER_GROUP(inode->i_sb);
2659
			inodes_per_buffer = bh->b_size /
2660
				EXT4_INODE_SIZE(inode->i_sb);
2661
			inode_offset = ((inode->i_ino - 1) %
2662
					EXT4_INODES_PER_GROUP(inode->i_sb));
2663 2664 2665
			start = inode_offset & ~(inodes_per_buffer - 1);

			/* Is the inode bitmap in cache? */
2666
			desc = ext4_get_group_desc(inode->i_sb,
2667 2668 2669 2670 2671
						block_group, NULL);
			if (!desc)
				goto make_io;

			bitmap_bh = sb_getblk(inode->i_sb,
2672
				ext4_inode_bitmap(inode->i_sb, desc));
2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687
			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;
2688
				if (ext4_test_bit(i, bitmap_bh->b_data))
2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711
					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)) {
2712
			ext4_error(inode->i_sb, "ext4_get_inode_loc",
2713
					"unable to read inode block - "
2714
					"inode=%lu, block=%llu",
2715 2716 2717 2718 2719 2720 2721 2722 2723 2724
					inode->i_ino, block);
			brelse(bh);
			return -EIO;
		}
	}
has_buffer:
	iloc->bh = bh;
	return 0;
}

2725
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
2726 2727
{
	/* We have all inode data except xattrs in memory here. */
2728 2729
	return __ext4_get_inode_loc(inode, iloc,
		!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
2730 2731
}

2732
void ext4_set_inode_flags(struct inode *inode)
2733
{
2734
	unsigned int flags = EXT4_I(inode)->i_flags;
2735 2736

	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2737
	if (flags & EXT4_SYNC_FL)
2738
		inode->i_flags |= S_SYNC;
2739
	if (flags & EXT4_APPEND_FL)
2740
		inode->i_flags |= S_APPEND;
2741
	if (flags & EXT4_IMMUTABLE_FL)
2742
		inode->i_flags |= S_IMMUTABLE;
2743
	if (flags & EXT4_NOATIME_FL)
2744
		inode->i_flags |= S_NOATIME;
2745
	if (flags & EXT4_DIRSYNC_FL)
2746 2747 2748
		inode->i_flags |= S_DIRSYNC;
}

2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766
/* 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;
}
2767 2768 2769 2770
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
2771 2772
	struct inode *inode = &(ei->vfs_inode);
	struct super_block *sb = inode->i_sb;
2773 2774 2775 2776 2777 2778

	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
2779 2780 2781 2782 2783 2784
		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;
		}
2785 2786 2787 2788
	} else {
		return le32_to_cpu(raw_inode->i_blocks_lo);
	}
}
2789

2790
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
2791
{
2792 2793
	struct ext4_iloc iloc;
	struct ext4_inode *raw_inode;
2794
	struct ext4_inode_info *ei;
2795
	struct buffer_head *bh;
2796 2797
	struct inode *inode;
	long ret;
2798 2799
	int block;

2800 2801 2802 2803 2804 2805 2806
	inode = iget_locked(sb, ino);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;

	ei = EXT4_I(inode);
2807 2808 2809
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
	ei->i_acl = EXT4_ACL_NOT_CACHED;
	ei->i_default_acl = EXT4_ACL_NOT_CACHED;
2810 2811 2812
#endif
	ei->i_block_alloc_info = NULL;

2813 2814
	ret = __ext4_get_inode_loc(inode, &iloc, 0);
	if (ret < 0)
2815 2816
		goto bad_inode;
	bh = iloc.bh;
2817
	raw_inode = ext4_raw_inode(&iloc);
2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836
	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 ||
2837
		    !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
2838 2839
			/* this inode is deleted */
			brelse (bh);
2840
			ret = -ESTALE;
2841 2842 2843 2844 2845 2846 2847 2848
			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);
2849
	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
2850
	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
2851
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
2852
	    cpu_to_le32(EXT4_OS_HURD)) {
B
Badari Pulavarty 已提交
2853 2854
		ei->i_file_acl |=
			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
2855
	}
2856
	inode->i_size = ext4_isize(raw_inode);
2857 2858 2859 2860 2861 2862 2863
	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!
	 */
2864
	for (block = 0; block < EXT4_N_BLOCKS; block++)
2865 2866 2867
		ei->i_data[block] = raw_inode->i_block[block];
	INIT_LIST_HEAD(&ei->i_orphan);

2868
	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
2869
		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2870
		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2871 2872
		    EXT4_INODE_SIZE(inode->i_sb)) {
			brelse (bh);
2873
			ret = -EIO;
2874
			goto bad_inode;
2875
		}
2876 2877
		if (ei->i_extra_isize == 0) {
			/* The extra space is currently unused. Use it. */
2878 2879
			ei->i_extra_isize = sizeof(struct ext4_inode) -
					    EXT4_GOOD_OLD_INODE_SIZE;
2880 2881
		} else {
			__le32 *magic = (void *)raw_inode +
2882
					EXT4_GOOD_OLD_INODE_SIZE +
2883
					ei->i_extra_isize;
2884 2885
			if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
				 ei->i_state |= EXT4_STATE_XATTR;
2886 2887 2888 2889
		}
	} else
		ei->i_extra_isize = 0;

K
Kalpak Shah 已提交
2890 2891 2892 2893 2894
	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);

2895 2896 2897 2898 2899 2900 2901
	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;
	}

2902
	if (S_ISREG(inode->i_mode)) {
2903 2904 2905
		inode->i_op = &ext4_file_inode_operations;
		inode->i_fop = &ext4_file_operations;
		ext4_set_aops(inode);
2906
	} else if (S_ISDIR(inode->i_mode)) {
2907 2908
		inode->i_op = &ext4_dir_inode_operations;
		inode->i_fop = &ext4_dir_operations;
2909
	} else if (S_ISLNK(inode->i_mode)) {
2910 2911
		if (ext4_inode_is_fast_symlink(inode))
			inode->i_op = &ext4_fast_symlink_inode_operations;
2912
		else {
2913 2914
			inode->i_op = &ext4_symlink_inode_operations;
			ext4_set_aops(inode);
2915 2916
		}
	} else {
2917
		inode->i_op = &ext4_special_inode_operations;
2918 2919 2920 2921 2922 2923 2924 2925
		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);
2926
	ext4_set_inode_flags(inode);
2927 2928
	unlock_new_inode(inode);
	return inode;
2929 2930

bad_inode:
2931 2932
	iget_failed(inode);
	return ERR_PTR(ret);
2933 2934
}

2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948
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
2949
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
2950
		raw_inode->i_blocks_high = 0;
A
Aneesh Kumar K.V 已提交
2951
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
2952 2953 2954 2955 2956 2957 2958 2959 2960 2961
	} 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
2962
		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
2963
		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
A
Aneesh Kumar K.V 已提交
2964
		ei->i_flags &= ~EXT4_HUGE_FILE_FL;
2965
	} else {
A
Aneesh Kumar K.V 已提交
2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978
		/*
		 * 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);
2979 2980 2981 2982 2983
	}
err_out:
	return err;
}

2984 2985 2986 2987 2988 2989 2990
/*
 * 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.
 */
2991
static int ext4_do_update_inode(handle_t *handle,
2992
				struct inode *inode,
2993
				struct ext4_iloc *iloc)
2994
{
2995 2996
	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
	struct ext4_inode_info *ei = EXT4_I(inode);
2997 2998 2999 3000 3001
	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. */
3002 3003
	if (ei->i_state & EXT4_STATE_NEW)
		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
3004

3005
	ext4_get_inode_flags(ei);
3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031
	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
3032 3033 3034 3035 3036 3037

	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);

3038 3039
	if (ext4_inode_blocks_set(handle, raw_inode, ei))
		goto out_brelse;
3040
	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3041 3042
	/* clear the migrate flag in the raw_inode */
	raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
3043 3044
	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
	    cpu_to_le32(EXT4_OS_HURD))
B
Badari Pulavarty 已提交
3045 3046
		raw_inode->i_file_acl_high =
			cpu_to_le16(ei->i_file_acl >> 32);
3047
	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063
	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,
3064
					EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
3065 3066 3067 3068
			sb->s_dirt = 1;
			handle->h_sync = 1;
			err = ext4_journal_dirty_metadata(handle,
					EXT4_SB(sb)->s_sbh);
3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082
		}
	}
	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;
		}
3083
	} else for (block = 0; block < EXT4_N_BLOCKS; block++)
3084 3085
		raw_inode->i_block[block] = ei->i_data[block];

3086 3087 3088 3089 3090
	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);
3091
		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3092 3093
	}

3094

3095 3096
	BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
	rc = ext4_journal_dirty_metadata(handle, bh);
3097 3098
	if (!err)
		err = rc;
3099
	ei->i_state &= ~EXT4_STATE_NEW;
3100 3101 3102

out_brelse:
	brelse (bh);
3103
	ext4_std_error(inode->i_sb, err);
3104 3105 3106 3107
	return err;
}

/*
3108
 * ext4_write_inode()
3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124
 *
 * 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
3125
 * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141
 * 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.
 */
3142
int ext4_write_inode(struct inode *inode, int wait)
3143 3144 3145 3146
{
	if (current->flags & PF_MEMALLOC)
		return 0;

3147
	if (ext4_journal_current_handle()) {
M
Mingming Cao 已提交
3148
		jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3149 3150 3151 3152 3153 3154 3155
		dump_stack();
		return -EIO;
	}

	if (!wait)
		return 0;

3156
	return ext4_force_commit(inode->i_sb);
3157 3158 3159
}

/*
3160
 * ext4_setattr()
3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175
 *
 * 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.
 */
3176
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191
{
	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) */
3192 3193
		handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
					EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
3194 3195 3196 3197 3198 3199
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}
		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
		if (error) {
3200
			ext4_journal_stop(handle);
3201 3202 3203 3204 3205 3206 3207 3208
			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;
3209 3210
		error = ext4_mark_inode_dirty(handle, inode);
		ext4_journal_stop(handle);
3211 3212
	}

3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223
	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;
			}
		}
	}

3224 3225 3226 3227
	if (S_ISREG(inode->i_mode) &&
	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
		handle_t *handle;

3228
		handle = ext4_journal_start(inode, 3);
3229 3230 3231 3232 3233
		if (IS_ERR(handle)) {
			error = PTR_ERR(handle);
			goto err_out;
		}

3234 3235 3236
		error = ext4_orphan_add(handle, inode);
		EXT4_I(inode)->i_disksize = attr->ia_size;
		rc = ext4_mark_inode_dirty(handle, inode);
3237 3238
		if (!error)
			error = rc;
3239
		ext4_journal_stop(handle);
3240 3241 3242 3243
	}

	rc = inode_setattr(inode, attr);

3244
	/* If inode_setattr's call to ext4_truncate failed to get a
3245 3246 3247
	 * transaction handle at all, we need to clean up the in-core
	 * orphan list manually. */
	if (inode->i_nlink)
3248
		ext4_orphan_del(NULL, inode);
3249 3250

	if (!rc && (ia_valid & ATTR_MODE))
3251
		rc = ext4_acl_chmod(inode);
3252 3253

err_out:
3254
	ext4_std_error(inode->i_sb, error);
3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272
	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.
3273
 * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
3274
 *
3275
 * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287
 *
 * 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
3288
int ext4_writepage_trans_blocks(struct inode *inode)
3289
{
3290 3291
	int bpp = ext4_journal_blocks_per_page(inode);
	int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
3292 3293
	int ret;

A
Alex Tomas 已提交
3294 3295 3296
	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
		return ext4_ext_writepage_trans_blocks(inode, bpp);

3297
	if (ext4_should_journal_data(inode))
3298 3299 3300 3301 3302 3303 3304
		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 */
3305
	ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
3306 3307 3308 3309 3310 3311
#endif

	return ret;
}

/*
3312
 * The caller must have previously called ext4_reserve_inode_write().
3313 3314
 * Give this, we know that the caller already has write access to iloc->bh.
 */
3315 3316
int ext4_mark_iloc_dirty(handle_t *handle,
		struct inode *inode, struct ext4_iloc *iloc)
3317 3318 3319
{
	int err = 0;

3320 3321 3322
	if (test_opt(inode->i_sb, I_VERSION))
		inode_inc_iversion(inode);

3323 3324 3325
	/* the do_update_inode consumes one bh->b_count */
	get_bh(iloc->bh);

3326
	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
3327
	err = ext4_do_update_inode(handle, inode, iloc);
3328 3329 3330 3331 3332 3333 3334 3335 3336 3337
	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
3338 3339
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
			 struct ext4_iloc *iloc)
3340 3341 3342
{
	int err = 0;
	if (handle) {
3343
		err = ext4_get_inode_loc(inode, iloc);
3344 3345
		if (!err) {
			BUFFER_TRACE(iloc->bh, "get_write_access");
3346
			err = ext4_journal_get_write_access(handle, iloc->bh);
3347 3348 3349 3350 3351 3352
			if (err) {
				brelse(iloc->bh);
				iloc->bh = NULL;
			}
		}
	}
3353
	ext4_std_error(inode->i_sb, err);
3354 3355 3356
	return err;
}

3357 3358 3359 3360
/*
 * 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
3361 3362 3363 3364
static int ext4_expand_extra_isize(struct inode *inode,
				   unsigned int new_extra_isize,
				   struct ext4_iloc iloc,
				   handle_t *handle)
3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391
{
	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);
}

3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412
/*
 * 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.
 */
3413
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
3414
{
3415
	struct ext4_iloc iloc;
3416 3417 3418
	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
	static unsigned int mnt_count;
	int err, ret;
3419 3420

	might_sleep();
3421
	err = ext4_reserve_inode_write(handle, inode, &iloc);
3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437
	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
3438 3439
				if (mnt_count !=
					le16_to_cpu(sbi->s_es->s_mnt_count)) {
3440
					ext4_warning(inode->i_sb, __func__,
3441 3442 3443
					"Unable to expand inode %lu. Delete"
					" some EAs or run e2fsck.",
					inode->i_ino);
A
Aneesh Kumar K.V 已提交
3444 3445
					mnt_count =
					  le16_to_cpu(sbi->s_es->s_mnt_count);
3446 3447 3448 3449
				}
			}
		}
	}
3450
	if (!err)
3451
		err = ext4_mark_iloc_dirty(handle, inode, &iloc);
3452 3453 3454 3455
	return err;
}

/*
3456
 * ext4_dirty_inode() is called from __mark_inode_dirty()
3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468
 *
 * 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.
 */
3469
void ext4_dirty_inode(struct inode *inode)
3470
{
3471
	handle_t *current_handle = ext4_journal_current_handle();
3472 3473
	handle_t *handle;

3474
	handle = ext4_journal_start(inode, 2);
3475 3476 3477 3478 3479 3480
	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",
3481
		       __func__);
3482 3483 3484
	} else {
		jbd_debug(5, "marking dirty.  outer handle=%p\n",
				current_handle);
3485
		ext4_mark_inode_dirty(handle, inode);
3486
	}
3487
	ext4_journal_stop(handle);
3488 3489 3490 3491 3492 3493 3494 3495
out:
	return;
}

#if 0
/*
 * Bind an inode's backing buffer_head into this transaction, to prevent
 * it from being flushed to disk early.  Unlike
3496
 * ext4_reserve_inode_write, this leaves behind no bh reference and
3497 3498 3499
 * returns no iloc structure, so the caller needs to repeat the iloc
 * lookup to mark the inode dirty later.
 */
3500
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
3501
{
3502
	struct ext4_iloc iloc;
3503 3504 3505

	int err = 0;
	if (handle) {
3506
		err = ext4_get_inode_loc(inode, &iloc);
3507 3508
		if (!err) {
			BUFFER_TRACE(iloc.bh, "get_write_access");
3509
			err = jbd2_journal_get_write_access(handle, iloc.bh);
3510
			if (!err)
3511
				err = ext4_journal_dirty_metadata(handle,
3512 3513 3514 3515
								  iloc.bh);
			brelse(iloc.bh);
		}
	}
3516
	ext4_std_error(inode->i_sb, err);
3517 3518 3519 3520
	return err;
}
#endif

3521
int ext4_change_inode_journal_flag(struct inode *inode, int val)
3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536
{
	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.
	 */

3537
	journal = EXT4_JOURNAL(inode);
3538
	if (is_journal_aborted(journal))
3539 3540
		return -EROFS;

3541 3542
	jbd2_journal_lock_updates(journal);
	jbd2_journal_flush(journal);
3543 3544 3545 3546 3547 3548 3549 3550 3551 3552

	/*
	 * 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)
3553
		EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
3554
	else
3555 3556
		EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
	ext4_set_aops(inode);
3557

3558
	jbd2_journal_unlock_updates(journal);
3559 3560 3561

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

3562
	handle = ext4_journal_start(inode, 1);
3563 3564 3565
	if (IS_ERR(handle))
		return PTR_ERR(handle);

3566
	err = ext4_mark_inode_dirty(handle, inode);
3567
	handle->h_sync = 1;
3568 3569
	ext4_journal_stop(handle);
	ext4_std_error(inode->i_sb, err);
3570 3571 3572

	return err;
}
3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633

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

int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{
	loff_t size;
	unsigned long len;
	int ret = -EINVAL;
	struct file *file = vma->vm_file;
	struct inode *inode = file->f_path.dentry->d_inode;
	struct address_space *mapping = inode->i_mapping;

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

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

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