path: root/fs/logfs/journal.c

/*
 * fs/logfs/journal.c	- journal handling code
 *
 * As should be obvious for Linux kernel code, license is GPLv2
 *
 * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
 */
#include "logfs.h"
#include <linux/slab.h>

static void logfs_calc_free(struct super_block *sb)
{
	struct logfs_super *super = logfs_super(sb);
	u64 reserve, no_segs = super->s_no_segs;
	s64 free;
	int i;

	/* superblock segments */
	no_segs -= 2;
	super->s_no_journal_segs = 0;
	/* journal */
	journal_for_each(i)
		if (super->s_journal_seg[i]) {
			no_segs--;
			super->s_no_journal_segs++;
		}

	/* open segments plus one extra per level for GC */
	no_segs -= 2 * super->s_total_levels;

	free = no_segs * (super->s_segsize - LOGFS_SEGMENT_RESERVE);
	free -= super->s_used_bytes;
	/* just a bit extra */
	free -= super->s_total_levels * 4096;

	/* Bad blocks are 'paid' for with speed reserve - the filesystem
	 * simply gets slower as bad blocks accumulate.  Until the bad blocks
	 * exceed the speed reserve - then the filesystem gets smaller.
	 */
	reserve = super->s_bad_segments + super->s_bad_seg_reserve;
	reserve *= super->s_segsize - LOGFS_SEGMENT_RESERVE;
	reserve = max(reserve, super->s_speed_reserve);
	free -= reserve;
	if (free < 0)
		free = 0;

	super->s_free_bytes = free;
}

static void reserve_sb_and_journal(struct super_block *sb)
{
	struct logfs_super *super = logfs_super(sb);
	struct btree_head32 *head = &super->s_reserved_segments;
	int i, err;

	err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[0]), (void *)1,
			GFP_KERNEL);
	BUG_ON(err);

	err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[1]), (void *)1,
			GFP_KERNEL);
	BUG_ON(err);

	journal_for_each(i) {
		if (!super->s_journal_seg[i])
			continue;
		err = btree_insert32(head, super->s_journal_seg[i], (void *)1,
				GFP_KERNEL);
		BUG_ON(err);
	}
}

static void read_dynsb(struct super_block *sb,
		struct logfs_je_dynsb *dynsb)
{
	struct logfs_super *super = logfs_super(sb);

	super->s_gec		= be64_to_cpu(dynsb->ds_gec);
	super->s_sweeper	= be64_to_cpu(dynsb->ds_sweeper);
	super->s_victim_ino	= be64_to_cpu(dynsb->ds_victim_ino);
	super->s_rename_dir	= be64_to_cpu(dynsb->ds_rename_dir);
	super->s_rename_pos	= be64_to_cpu(dynsb->ds_rename_pos);
	super->s_used_bytes	= be64_to_cpu(dynsb->ds_used_bytes);
	super->s_generation	= be32_to_cpu(dynsb->ds_generation);
}

static void read_anchor(struct super_block *sb,
		struct logfs_je_anchor *da)
{
	struct logfs_super *super = logfs_super(sb);
	struct inode *inode = super->s_master_inode;
	struct logfs_inode *li = logfs_inode(inode);
	int i;

	super->s_last_ino = be64_to_cpu(da->da_last_ino);
	li->li_flags	= 0;
	li->li_height	= da->da_height;
	i_size_write(inode, be64_to_cpu(da->da_size));
	li->li_used_bytes = be64_to_cpu(da->da_used_bytes);

	for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
		li->li_data[i] = be64_to_cpu(da->da_data[i]);
}

static void read_erasecount(struct super_block *sb,
		struct logfs_je_journal_ec *ec)
{
	struct logfs_super *super = logfs_super(sb);
	int i;

	journal_for_each(i)
		super->s_journal_ec[i] = be32_to_cpu(ec->ec[i]);
}

static int read_area(struct super_block *sb, struct logfs_je_area *a)
{
	struct logfs_super *super = logfs_super(sb);
	struct logfs_area *area = super->s_area[a->gc_level];
	u64 ofs;
	u32 writemask = ~(super->s_writesize - 1);

	if (a->gc_level >= LOGFS_NO_AREAS)
		return -EIO;
	if (a->vim != VIM_DEFAULT)
		return -EIO; /* TODO: close area and continue */

	area->a_used_bytes = be32_to_cpu(a->used_bytes);
	area->a_written_bytes = area->a_used_bytes & writemask;
	area->a_segno = be32_to_cpu(a->segno);
	if (area->a_segno)
		area->a_is_open = 1;

	ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
	if (super->s_writesize