[LogFS] add new flash file system

This is a new flash file system. See
Documentation/filesystems/logfs.txt

Signed-off-by: Joern Engel <joern@logfs.org>

1 files changed, 722 insertions, 0 deletions

diff --git a/fs/logfs/logfs.h b/fs/logfs/logfs.h
new file mode 100644
index 000000000000..e3082abe9e3b
--- /dev/null
+++ b/fs/logfs/logfs.h
@@ -0,0 +1,722 @@
+/*
+ * fs/logfs/logfs.h
+ *
+ * As should be obvious for Linux kernel code, license is GPLv2
+ *
+ * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
+ *
+ * Private header for logfs.
+ */
+#ifndef FS_LOGFS_LOGFS_H
+#define FS_LOGFS_LOGFS_H
+
+#undef __CHECK_ENDIAN__
+#define __CHECK_ENDIAN__
+
+#include <linux/btree.h>
+#include <linux/crc32.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/mempool.h>
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include "logfs_abi.h"
+
+#define LOGFS_DEBUG_SUPER	(0x0001)
+#define LOGFS_DEBUG_SEGMENT	(0x0002)
+#define LOGFS_DEBUG_JOURNAL	(0x0004)
+#define LOGFS_DEBUG_DIR		(0x0008)
+#define LOGFS_DEBUG_FILE	(0x0010)
+#define LOGFS_DEBUG_INODE	(0x0020)
+#define LOGFS_DEBUG_READWRITE	(0x0040)
+#define LOGFS_DEBUG_GC		(0x0080)
+#define LOGFS_DEBUG_GC_NOISY	(0x0100)
+#define LOGFS_DEBUG_ALIASES	(0x0200)
+#define LOGFS_DEBUG_BLOCKMOVE	(0x0400)
+#define LOGFS_DEBUG_ALL		(0xffffffff)
+
+#define LOGFS_DEBUG		(0x01)
+/*
+ * To enable specific log messages, simply define LOGFS_DEBUG to match any
+ * or all of the above.
+ */
+#ifndef LOGFS_DEBUG
+#define LOGFS_DEBUG		(0)
+#endif
+
+#define log_cond(cond, fmt, arg...) do {	\
+	if (cond)				\
+		printk(KERN_DEBUG fmt, ##arg);	\
+} while (0)
+
+#define log_super(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SUPER, fmt, ##arg)
+#define log_segment(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SEGMENT, fmt, ##arg)
+#define log_journal(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_JOURNAL, fmt, ##arg)
+#define log_dir(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_DIR, fmt, ##arg)
+#define log_file(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_FILE, fmt, ##arg)
+#define log_inode(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_INODE, fmt, ##arg)
+#define log_readwrite(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_READWRITE, fmt, ##arg)
+#define log_gc(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC, fmt, ##arg)
+#define log_gc_noisy(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC_NOISY, fmt, ##arg)
+#define log_aliases(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_ALIASES, fmt, ##arg)
+#define log_blockmove(fmt, arg...) \
+	log_cond(LOGFS_DEBUG & LOGFS_DEBUG_BLOCKMOVE, fmt, ##arg)
+
+#define PG_pre_locked		PG_owner_priv_1
+#define PagePreLocked(page)	test_bit(PG_pre_locked, &(page)->flags)
+#define SetPagePreLocked(page)	set_bit(PG_pre_locked, &(page)->flags)
+#define ClearPagePreLocked(page) clear_bit(PG_pre_locked, &(page)->flags)
+
+/* FIXME: This should really be somewhere in the 64bit area. */
+#define LOGFS_LINK_MAX		(1<<30)
+
+/* Read-only filesystem */
+#define LOGFS_SB_FLAG_RO	0x0001
+#define LOGFS_SB_FLAG_SEG_ALIAS	0x0002
+#define LOGFS_SB_FLAG_OBJ_ALIAS	0x0004
+#define LOGFS_SB_FLAG_SHUTDOWN	0x0008
+
+/* Write Control Flags */
+#define WF_LOCK			0x01 /* take write lock */
+#define WF_WRITE		0x02 /* write block */
+#define WF_DELETE		0x04 /* delete old block */
+
+typedef u8 __bitwise level_t;
+typedef u8 __bitwise gc_level_t;
+
+#define LEVEL(level) ((__force level_t)(level))
+#define GC_LEVEL(gc_level) ((__force gc_level_t)(gc_level))
+
+#define SUBLEVEL(level) ( (void)((level) == LEVEL(1)),	\
+		(__force level_t)((__force u8)(level) - 1) )
+
+/**
+ * struct logfs_area - area management information
+ *
+ * @a_sb:			the superblock this area belongs to
+ * @a_is_open:			1 if the area is currently open, else 0
+ * @a_segno:			segment number of area
+ * @a_written_bytes:		number of bytes already written back
+ * @a_used_bytes:		number of used bytes
+ * @a_ops:			area operations (either journal or ostore)
+ * @a_erase_count:		erase count
+ * @a_level:			GC level
+ */
+struct logfs_area { /* a segment open for writing */
+	struct super_block *a_sb;
+	int	a_is_open;
+	u32	a_segno;
+	u32	a_written_bytes;
+	u32	a_used_bytes;
+	const struct logfs_area_ops *a_ops;
+	u32	a_erase_count;
+	gc_level_t a_level;
+};
+
+/**
+ * struct logfs_area_ops - area operations
+ *
+ * @get_free_segment:		fill area->ofs with the offset of a free segment
+ * @get_erase_count:		fill area->erase_count (needs area->ofs)
+ * @erase_segment:		erase and setup segment
+ */
+struct logfs_area_ops {
+	void	(*get_free_segment)(struct logfs_area *area);
+	void	(*get_erase_count)(struct logfs_area *area);
+	int	(*erase_segment)(struct logfs_area *area);
+};
+
+/**
+ * struct logfs_device_ops - device access operations
+ *
+ * @readpage:			read one page (mm page)
+ * @writeseg:			write one segment.  may be a partial segment
+ * @erase:			erase one segment
+ * @read:			read from the device
+ * @erase:			erase part of the device
+ */
+struct logfs_device_ops {
+	struct page *(*find_first_sb)(struct super_block *sb, u64 *ofs);
+	struct page *(*find_last_sb)(struct super_block *sb, u64 *ofs);
+	int (*write_sb)(struct super_block *sb, struct page *page);
+	int (*readpage)(void *_sb, struct page *page);
+	void (*writeseg)(struct super_block *sb, u64 ofs, size_t len);
+	int (*erase)(struct super_block *sb, loff_t ofs, size_t len);
+	void (*sync)(struct super_block *sb);
+	void (*put_device)(struct super_block *sb);
+};
+
+/**
+ * struct candidate_list - list of similar candidates
+ */
+struct candidate_list {
+	struct rb_root rb_tree;
+	int count;
+	int maxcount;
+	int sort_by_ec;
+};
+
+/**
+ * struct gc_candidate - "candidate" segment to be garbage collected next
+ *
+ * @list:			list (either free of low)
+ * @segno:			segment number
+ * @valid:			number of valid bytes
+ * @erase_count:		erase count of segment
+ * @dist:			distance from tree root
+ *
+ * Candidates can be on two lists.  The free list contains electees rather
+ * than candidates - segments that no longer contain any valid data.  The
+ * low list contains candidates to be picked for GC.  It should be kept
+ * short.  It is not required to always pick a perfect candidate.  In the
+ * worst case GC will have to move more data than absolutely necessary.
+ */
+struct gc_candidate {
+	struct rb_node rb_node;
+	struct candidate_list *list;
+	u32	segno;
+	u32	valid;
+	u32	erase_count;
+	u8	dist;
+};
+
+/**
+ * struct logfs_journal_entry - temporary structure used during journal scan
+ *
+ * @used:
+ * @version:			normalized version
+ * @len:			length
+ * @offset:			offset
+ */
+struct logfs_journal_entry {
+	int used;
+	s16 version;
+	u16 len;
+	u16 datalen;
+	u64 offset;
+};
+
+enum transaction_state {
+	CREATE_1 = 1,
+	CREATE_2,
+	UNLINK_1,
+	UNLINK_2,
+	CROSS_RENAME_1,
+	CROSS_RENAME_2,
+	TARGET_RENAME_1,
+	TARGET_RENAME_2,
+	TARGET_RENAME_3
+};
+
+/**
+ * struct logfs_transaction - essential fields to support atomic dirops
+ *
+ * @ino:			target inode
+ * @dir:			inode of directory containing dentry
+ * @pos:			pos of dentry in directory
+ */
+struct logfs_transaction {
+	enum transaction_state state;
+	u64	 ino;
+	u64	 dir;
+	u64	 pos;
+};
+
+/**
+ * struct logfs_shadow - old block in the shadow of a not-yet-committed new one
+ * @old_ofs:			offset of old block on medium
+ * @new_ofs:			offset of new block on medium
+ * @ino:			inode number
+ * @bix:			block index
+ * @old_len:			size of old block, including header
+ * @new_len:			size of new block, including header
+ * @level:			block level
+ */
+struct logfs_shadow {
+	u64 old_ofs;
+	u64 new_ofs;
+	u64 ino;
+	u64 bix;
+	int old_len;
+	int new_len;
+	gc_level_t gc_level;
+};
+
+/**
+ * struct shadow_tree
+ * @new:			shadows where old_ofs==0, indexed by new_ofs
+ * @old:			shadows where old_ofs!=0, indexed by old_ofs
+ */
+struct shadow_tree {
+	struct btree_head64 new;
+	struct btree_head64 old;
+};
+
+struct object_alias_item {
+	struct list_head list;
+	__be64 val;
+	int child_no;
+};
+
+/**
+ * struct logfs_block - contains any block state
+ * @type:			indirect block or inode
+ * @full:			number of fully populated children
+ * @partial:			number of partially populated children
+ *
+ * Most blocks are directly represented by page cache pages.  But when a block
+ * becomes dirty, is part of a transaction, contains aliases or is otherwise
+ * special, a struct logfs_block is allocated to track the additional state.
+ * Inodes are very similar to indirect blocks, so they can also get one of
+ * these structures added when appropriate.
+ */
+#define BLOCK_INDIRECT	1	/* Indirect block */
+#define BLOCK_INODE	2	/* Inode */
+struct logfs_block_ops;
+struct logfs_block {
+	struct list_head alias_list;
+	struct list_head item_list;
+	struct super_block *sb;
+	u64 ino;
+	u64 bix;
+	level_t level;
+	struct page *page;
+	struct inode *inode;
+	struct logfs_transaction *ta;
+	unsigned long alias_map[LOGFS_BLOCK_FACTOR / BITS_PER_LONG];
+	struct logfs_block_ops *ops;
+	int full;
+	int partial;
+	int reserved_bytes;
+};
+
+typedef int write_alias_t(struct super_block *sb, u64 ino, u64 bix,
+		level_t level, int child_no, __be64 val);
+struct logfs_block_ops {
+	void	(*write_block)(struct logfs_block *block);
+	gc_level_t	(*block_level)(struct logfs_block *block);
+	void	(*free_block)(struct super_block *sb, struct logfs_block*block);
+	int	(*write_alias)(struct super_block *sb,
+			struct logfs_block *block,
+			write_alias_t *write_one_alias);
+};
+
+struct logfs_super {
+	struct mtd_info *s_mtd;			/* underlying device */
+	struct block_device *s_bdev;		/* underlying device */
+	const struct logfs_device_ops *s_devops;/* device access */
+	struct inode	*s_master_inode;	/* inode file */
+	struct inode	*s_segfile_inode;	/* segment file */
+	struct inode *s_mapping_inode;		/* device mapping */
+	atomic_t s_pending_writes;		/* outstanting bios */
+	long	 s_flags;
+	mempool_t *s_btree_pool;		/* for btree nodes */
+	mempool_t *s_alias_pool;		/* aliases in segment.c */
+	u64	 s_feature_incompat;
+	u64	 s_feature_ro_compat;
+	u64	 s_feature_compat;
+	u64	 s_feature_flags;
+	u64	 s_sb_ofs[2];
+	/* alias.c fields */
+	struct btree_head32 s_segment_alias;	/* remapped segments */
+	int	 s_no_object_aliases;
+	struct list_head s_object_alias;	/* remapped objects */
+	struct btree_head128 s_object_alias_tree; /* remapped objects */
+	struct mutex s_object_alias_mutex;
+	/* dir.c fields */
+	struct mutex s_dirop_mutex;		/* for creat/unlink/rename */
+	u64	 s_victim_ino;			/* used for atomic dir-ops */
+	u64	 s_rename_dir;			/* source directory ino */
+	u64	 s_rename_pos;			/* position of source dd */
+	/* gc.c fields */
+	long	 s_segsize;			/* size of a segment */
+	int	 s_segshift;			/* log2 of segment size */
+	long	 s_segmask;			/* 1 << s_segshift - 1 */
+	long	 s_no_segs;			/* segments on device */
+	long	 s_no_journal_segs;		/* segments used for journal */
+	long	 s_no_blocks;			/* blocks per segment */
+	long	 s_writesize;			/* minimum write size */
+	int	 s_writeshift;			/* log2 of write size */
+	u64	 s_size;			/* filesystem size */
+	struct logfs_area *s_area[LOGFS_NO_AREAS];	/* open segment array */
+	u64	 s_gec;				/* global erase count */
+	u64	 s_wl_gec_ostore;		/* time of last wl event */
+	u64	 s_wl_gec_journal;		/* time of last wl event */
+	u64	 s_sweeper;			/* current sweeper pos */
+	u8	 s_ifile_levels;		/* max level of ifile */
+	u8	 s_iblock_levels;		/* max level of regular files */
+	u8	 s_data_levels;			/* # of segments to leaf block*/
+	u8	 s_total_levels;		/* sum of above three */
+	struct btree_head32 s_cand_tree;	/* all candidates */
+	struct candidate_list s_free_list;	/* 100% free segments */
+	struct candidate_list s_reserve_list;	/* Bad segment reserve */
+	struct candidate_list s_low_list[LOGFS_NO_AREAS];/* good candidates */
+	struct candidate_list s_ec_list;	/* wear level candidates */
+	struct btree_head32 s_reserved_segments;/* sb, journal, bad, etc. */
+	/* inode.c fields */
+	u64	 s_last_ino;			/* highest ino used */
+	long	 s_inos_till_wrap;
+	u32	 s_generation;			/* i_generation for new files */
+	struct list_head s_freeing_list;	/* inodes being freed */
+	/* journal.c fields */
+	struct mutex s_journal_mutex;
+	void	*s_je;				/* journal entry to compress */
+	void	*s_compressed_je;		/* block to write to journal */
+	u32	 s_journal_seg[LOGFS_JOURNAL_SEGS]; /* journal segments */
+	u32	 s_journal_ec[LOGFS_JOURNAL_SEGS]; /* journal erasecounts */
+	u64	 s_last_version;
+	struct logfs_area *s_journal_area;	/* open journal segment */
+	__be64	s_je_array[64];
+	int	s_no_je;
+
+	int	 s_sum_index;			/* for the 12 summaries */
+	struct shadow_tree s_shadow_tree;
+	int	 s_je_fill;			/* index of current je */
+	/* readwrite.c fields */
+	struct mutex s_write_mutex;
+	int	 s_lock_count;
+	mempool_t *s_block_pool;		/* struct logfs_block pool */
+	mempool_t *s_shadow_pool;		/* struct logfs_shadow pool */
+	/*
+	 * Space accounting:
+	 * - s_used_bytes specifies space used to store valid data objects.
+	 * - s_dirty_used_bytes is space used to store non-committed data
+	 *   objects.  Those objects have already been written themselves,
+	 *   but they don't become valid until all indirect blocks up to the
+	 *   journal have been written as well.
+	 * - s_dirty_free_bytes is space used to store the old copy of a
+	 *   replaced object, as long as the replacement is non-committed.
+	 *   In other words, it is the amount of space freed when all dirty
+	 *   blocks are written back.
+	 * - s_free_bytes is the amount of free space available for any
+	 *   purpose.
+	 * - s_root_reserve is the amount of free space available only to
+	 *   the root user.  Non-privileged users can no longer write once
+	 *   this watermark has been reached.
+	 * - s_speed_reserve is space which remains unused to speed up
+	 *   garbage collection performance.
+	 * - s_dirty_pages is the space reserved for currently dirty pages.
+	 *   It is a pessimistic estimate, so some/most will get freed on
+	 *   page writeback.
+	 *
+	 * s_used_bytes + s_free_bytes + s_speed_reserve = total usable size
+	 */
+	u64	 s_free_bytes;
+	u64	 s_used_bytes;
+	u64	 s_dirty_free_bytes;
+	u64	 s_dirty_used_bytes;
+	u64	 s_root_reserve;
+	u64	 s_speed_reserve;
+	u64	 s_dirty_pages;
+	/* Bad block handling:
+	 * - s_bad_seg_reserve is a number of segments usually kept
+	 *   free.  When encountering bad blocks, the affected segment's data
+	 *   is _temporarily_ moved to a reserved segment.
+	 * - s_bad_segments is the number of known bad segments.
+	 */
+	u32	 s_bad_seg_reserve;
+	u32	 s_bad_segments;
+};
+
+/**
+ * struct logfs_inode - in-memory inode
+ *
+ * @vfs_inode:			struct inode
+ * @li_data:			data pointers
+ * @li_used_bytes:		number of used bytes
+ * @li_freeing_list:		used to track inodes currently being freed
+ * @li_flags:			inode flags
+ * @li_refcount:		number of internal (GC-induced) references
+ */
+struct logfs_inode {
+	struct inode vfs_inode;
+	u64	li_data[LOGFS_EMBEDDED_FIELDS];
+	u64	li_used_bytes;
+	struct list_head li_freeing_list;
+	struct logfs_block *li_block;
+	u32	li_flags;
+	u8	li_height;
+	int	li_refcount;
+};
+
+#define journal_for_each(__i) for (__i = 0; __i < LOGFS_JOURNAL_SEGS; __i++)
+#define for_each_area(__i) for (__i = 0; __i < LOGFS_NO_AREAS; __i++)
+#define for_each_area_down(__i) for (__i = LOGFS_NO_AREAS - 1; __i >= 0; __i--)
+
+/* compr.c */
+int logfs_compress(void *in, void *out, size_t inlen, size_t outlen);
+int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen);
+int __init logfs_compr_init(void);
+void logfs_compr_exit(void);
+
+/* dev_bdev.c */
+#ifdef CONFIG_BLOCK
+int logfs_get_sb_bdev(struct file_system_type *type, int flags,
+		const char *devname, struct vfsmount *mnt);
+#else
+static inline int logfs_get_sb_bdev(struct file_system_type *type, int flags,
+		const char *devname, struct vfsmount *mnt)
+{
+	return -ENODEV;
+}
+#endif
+
+/* dev_mtd.c */
+#ifdef CONFIG_MTD
+int logfs_get_sb_mtd(struct file_system_type *type, int flags,
+		int mtdnr, struct vfsmount *mnt);
+#else
+static inline int logfs_get_sb_mtd(struct file_system_type *type, int flags,
+		int mtdnr, struct vfsmount *mnt)
+{
+	return -ENODEV;
+}
+#endif
+
+/* dir.c */
+extern const struct inode_operations logfs_symlink_iops;
+extern const struct inode_operations logfs_dir_iops;
+extern const struct file_operations logfs_dir_fops;
+int logfs_replay_journal(struct super_block *sb);
+
+/* file.c */
+extern const struct inode_operations logfs_reg_iops;
+extern const struct file_operations logfs_reg_fops;
+extern const struct address_space_operations logfs_reg_aops;
+int logfs_readpage(struct file *file, struct page *page);
+int logfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		unsigned long arg);
+int logfs_fsync(struct file *file, struct dentry *dentry, int datasync);
+
+/* gc.c */
+u32 get_best_cand(struct super_block *sb, struct candidate_list *list, u32 *ec);
+void logfs_gc_pass(struct super_block *sb);
+int logfs_check_areas(struct super_block *sb);
+int logfs_init_gc(struct super_block *sb);
+void logfs_cleanup_gc(struct super_block *sb);
+
+/* inode.c */
+extern const struct super_operations logfs_super_operations;
+struct inode *logfs_iget(struct super_block *sb, ino_t ino);
+struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *cookie);
+void logfs_safe_iput(struct inode *inode, int cookie);
+struct inode *logfs_new_inode(struct inode *dir, int mode);
+struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino);
+struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino);
+int logfs_init_inode_cache(void);
+void logfs_destroy_inode_cache(void);
+void destroy_meta_inode(struct inode *inode);
+void logfs_set_blocks(struct inode *inode, u64 no);
+/* these logically belong into inode.c but actually reside in readwrite.c */
+int logfs_read_inode(struct inode *inode);
+int __logfs_write_inode(struct inode *inode, long flags);
+void logfs_delete_inode(struct inode *inode);
+void logfs_clear_inode(struct inode *inode);
+
+/* journal.c */
+void logfs_write_anchor(struct inode *inode);
+int logfs_init_journal(struct super_block *sb);
+void logfs_cleanup_journal(struct super_block *sb);
+int write_alias_journal(struct super_block *sb, u64 ino, u64 bix,
+		level_t level, int child_no, __be64 val);
+void do_logfs_journal_wl_pass(struct super_block *sb);
+
+/* readwrite.c */
+pgoff_t logfs_pack_index(u64 bix, level_t level);
+void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level);
+int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
+		loff_t bix, long flags, struct shadow_tree *shadow_tree);
+int logfs_readpage_nolock(struct page *page);
+int logfs_write_buf(struct inode *inode, struct page *page, long flags);
+int logfs_delete(struct inode *inode, pgoff_t index,
+		struct shadow_tree *shadow_tree);
+int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
+		gc_level_t gc_level, long flags);
+int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
+		gc_level_t gc_level);
+int logfs_truncate(struct inode *inode, u64 size);
+u64 logfs_seek_hole(struct inode *inode, u64 bix);
+u64 logfs_seek_data(struct inode *inode, u64 bix);
+int logfs_open_segfile(struct super_block *sb);
+int logfs_init_rw(struct super_block *sb);
+void logfs_cleanup_rw(struct super_block *sb);
+void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta);
+void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta);
+void logfs_write_block(struct logfs_block *block, long flags);
+int logfs_write_obj_aliases_pagecache(struct super_block *sb);
+void logfs_get_segment_entry(struct super_block *sb, u32 segno,
+		struct logfs_segment_entry *se);
+void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment);
+void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
+		gc_level_t gc_level);
+void logfs_set_segment_reserved(struct super_block *sb, u32 segno);
+void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec);
+struct logfs_block *__alloc_block(struct super_block *sb,
+		u64 ino, u64 bix, level_t level);
+void __free_block(struct super_block *sb, struct logfs_block *block);
+void btree_write_block(struct logfs_block *block);
+void initialize_block_counters(struct page *page, struct logfs_block *block,
+		__be64 *array, int page_is_empty);
+int logfs_exist_block(struct inode *inode, u64 bix);
+int get_page_reserve(struct inode *inode, struct page *page);
+extern struct logfs_block_ops indirect_block_ops;
+
+/* segment.c */
+int logfs_erase_segment(struct super_block *sb, u32 ofs);
+int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf);
+int logfs_segment_read(struct inode *inode, struct page *page, u64 ofs, u64 bix,
+		level_t level);
+int logfs_segment_write(struct inode *inode, struct page *page,
+		struct logfs_shadow *shadow);
+int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow);
+int logfs_load_object_aliases(struct super_block *sb,
+		struct logfs_obj_alias *oa, int count);
+void move_page_to_btree(struct page *page);
+int logfs_init_mapping(struct super_block *sb);
+void logfs_sync_area(struct logfs_area *area);
+void logfs_sync_segments(struct super_block *sb);
+
+/* area handling */
+int logfs_init_areas(struct super_block *sb);
+void logfs_cleanup_areas(struct super_block *sb);
+int logfs_open_area(struct logfs_area *area, size_t bytes);
+void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
+		int use_filler);
+
+static inline void logfs_buf_write(struct logfs_area *area, u64 ofs,
+		void *buf, size_t len)
+{
+	__logfs_buf_write(area, ofs, buf, len, 0);
+}
+
+static inline void logfs_buf_recover(struct logfs_area *area, u64 ofs,
+		void *buf, size_t len)
+{
+	__logfs_buf_write(area, ofs, buf, len, 1);
+}
+
+/* super.c */
+struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index);
+void emergency_read_end(struct page *page);
+void logfs_crash_dump(struct super_block *sb);
+void *memchr_inv(const void *s, int c, size_t n);
+int logfs_statfs(struct dentry *dentry, struct kstatfs *stats);
+int logfs_get_sb_device(struct file_system_type *type, int flags,
+		struct mtd_info *mtd, struct block_device *bdev,
+		const struct logfs_device_ops *devops, struct vfsmount *mnt);
+int logfs_check_ds(struct logfs_disk_super *ds);
+int logfs_write_sb(struct super_block *sb);
+
+static inline struct logfs_super *logfs_super(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct logfs_inode *logfs_inode(struct inode *inode)
+{
+	return container_of(inode, struct logfs_inode, vfs_inode);
+}
+
+static inline void logfs_set_ro(struct super_block *sb)
+{
+	logfs_super(sb)->s_flags |= LOGFS_SB_FLAG_RO;
+}
+
+#define LOGFS_BUG(sb) do {					\
+	struct super_block *__sb = sb;				\
+	logfs_crash_dump(__sb);					\
+	logfs_super(__sb)->s_flags |= LOGFS_SB_FLAG_RO;		\
+	BUG();							\
+} while (0)
+
+#define LOGFS_BUG_ON(condition, sb) \
+	do { if (unlikely(condition)) LOGFS_BUG((sb)); } while (0)
+
+static inline __be32 logfs_crc32(void *data, size_t len, size_t skip)
+{
+	return cpu_to_be32(crc32(~0, data+skip, len-skip));
+}
+
+static inline u8 logfs_type(struct inode *inode)
+{
+	return (inode->i_mode >> 12) & 15;
+}
+
+static inline pgoff_t logfs_index(struct super_block *sb, u64 pos)
+{
+	return pos >> sb->s_blocksize_bits;
+}
+
+static inline u64 dev_ofs(struct super_block *sb, u32 segno, u32 ofs)
+{
+	return ((u64)segno << logfs_super(sb)->s_segshift) + ofs;
+}
+
+static inline u32 seg_no(struct super_block *sb, u64 ofs)
+{
+	return ofs >> logfs_super(sb)->s_segshift;
+}
+
+static inline u32 seg_ofs(struct super_block *sb, u64 ofs)
+{
+	return ofs & logfs_super(sb)->s_segmask;
+}
+
+static inline u64 seg_align(struct super_block *sb, u64 ofs)
+{
+	return ofs & ~logfs_super(sb)->s_segmask;
+}
+
+static inline struct logfs_block *logfs_block(struct page *page)
+{
+	return (void *)page->private;
+}
+
+static inline level_t shrink_level(gc_level_t __level)
+{
+	u8 level = (__force u8)__level;
+
+	if (level >= LOGFS_MAX_LEVELS)
+		level -= LOGFS_MAX_LEVELS;
+	return (__force level_t)level;
+}
+
+static inline gc_level_t expand_level(u64 ino, level_t __level)
+{
+	u8 level = (__force u8)__level;
+
+	if (ino == LOGFS_INO_MASTER) {
+		/* ifile has seperate areas */
+		level += LOGFS_MAX_LEVELS;
+	}
+	return (__force gc_level_t)level;
+}
+
+static inline int logfs_block_shift(struct super_block *sb, level_t level)
+{
+	level = shrink_level((__force gc_level_t)level);
+	return (__force int)level * (sb->s_blocksize_bits - 3);
+}
+
+static inline u64 logfs_block_mask(struct super_block *sb, level_t level)
+{
+	return ~0ull << logfs_block_shift(sb, level);
+}
+
+static inline struct logfs_area *get_area(struct super_block *sb,
+		gc_level_t gc_level)
+{
+	return logfs_super(sb)->s_area[(__force u8)gc_level];
+}
+
+#endif