nilfs2: integrated block mapping

This adds structures and operations for the block mapping (bmap for
short).  NILFS2 uses direct mappings for short files or B-tree based
mappings for longer files.

Every on-disk data block is held with inodes and managed through this
block mapping.  The nilfs_bmap structure and a set of functions here
provide this capability to the NILFS2 inode.

[penberg@cs.helsinki.fi: remove a bunch of bmap wrapper macros]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Koji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 244 insertions, 0 deletions

diff --git a/fs/nilfs2/bmap.h b/fs/nilfs2/bmap.h
new file mode 100644
index 0000000..4f2708a
--- /dev/null
+++ b/fs/nilfs2/bmap.h
@@ -0,0 +1,244 @@
+/*
+ * bmap.h - NILFS block mapping.
+ *
+ * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Written by Koji Sato <koji@osrg.net>.
+ */
+
+#ifndef _NILFS_BMAP_H
+#define _NILFS_BMAP_H
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/nilfs2_fs.h>
+#include "alloc.h"
+
+#define NILFS_BMAP_INVALID_PTR	0
+
+#define nilfs_bmap_dkey_to_key(dkey)	le64_to_cpu(dkey)
+#define nilfs_bmap_key_to_dkey(key)	cpu_to_le64(key)
+#define nilfs_bmap_dptr_to_ptr(dptr)	le64_to_cpu(dptr)
+#define nilfs_bmap_ptr_to_dptr(ptr)	cpu_to_le64(ptr)
+
+#define nilfs_bmap_keydiff_abs(diff)	((diff) < 0 ? -(diff) : (diff))
+
+
+struct nilfs_bmap;
+
+/**
+ * union nilfs_bmap_ptr_req - request for bmap ptr
+ * @bpr_ptr: bmap pointer
+ * @bpr_req: request for persistent allocator
+ */
+union nilfs_bmap_ptr_req {
+	__u64 bpr_ptr;
+	struct nilfs_palloc_req bpr_req;
+};
+
+/**
+ * struct nilfs_bmap_stats - bmap statistics
+ * @bs_nblocks: number of blocks created or deleted
+ */
+struct nilfs_bmap_stats {
+	unsigned int bs_nblocks;
+};
+
+/**
+ * struct nilfs_bmap_operations - bmap operation table
+ */
+struct nilfs_bmap_operations {
+	int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
+	int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
+	int (*bop_delete)(struct nilfs_bmap *, __u64);
+	void (*bop_clear)(struct nilfs_bmap *);
+
+	int (*bop_propagate)(const struct nilfs_bmap *, struct buffer_head *);
+	void (*bop_lookup_dirty_buffers)(struct nilfs_bmap *,
+					 struct list_head *);
+
+	int (*bop_assign)(struct nilfs_bmap *,
+			  struct buffer_head **,
+			  sector_t,
+			  union nilfs_binfo *);
+	int (*bop_mark)(struct nilfs_bmap *, __u64, int);
+
+	/* The following functions are internal use only. */
+	int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);
+	int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
+	int (*bop_check_delete)(struct nilfs_bmap *, __u64);
+	int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
+};
+
+
+/**
+ * struct nilfs_bmap_ptr_operations - bmap ptr operation table
+ */
+struct nilfs_bmap_ptr_operations {
+	int (*bpop_prepare_alloc_ptr)(struct nilfs_bmap *,
+				      union nilfs_bmap_ptr_req *);
+	void (*bpop_commit_alloc_ptr)(struct nilfs_bmap *,
+				      union nilfs_bmap_ptr_req *);
+	void (*bpop_abort_alloc_ptr)(struct nilfs_bmap *,
+				     union nilfs_bmap_ptr_req *);
+	int (*bpop_prepare_start_ptr)(struct nilfs_bmap *,
+				      union nilfs_bmap_ptr_req *);
+	void (*bpop_commit_start_ptr)(struct nilfs_bmap *,
+				      union nilfs_bmap_ptr_req *,
+				      sector_t);
+	void (*bpop_abort_start_ptr)(struct nilfs_bmap *,
+				     union nilfs_bmap_ptr_req *);
+	int (*bpop_prepare_end_ptr)(struct nilfs_bmap *,
+				    union nilfs_bmap_ptr_req *);
+	void (*bpop_commit_end_ptr)(struct nilfs_bmap *,
+				    union nilfs_bmap_ptr_req *);
+	void (*bpop_abort_end_ptr)(struct nilfs_bmap *,
+				   union nilfs_bmap_ptr_req *);
+
+	int (*bpop_translate)(const struct nilfs_bmap *, __u64, __u64 *);
+};
+
+
+#define NILFS_BMAP_SIZE		(NILFS_INODE_BMAP_SIZE * sizeof(__le64))
+#define NILFS_BMAP_KEY_BIT	(sizeof(unsigned long) * 8 /* CHAR_BIT */)
+#define NILFS_BMAP_NEW_PTR_INIT	\
+	(1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))
+
+static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
+{
+	return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
+}
+
+
+/**
+ * struct nilfs_bmap - bmap structure
+ * @b_u: raw data
+ * @b_sem: semaphore
+ * @b_inode: owner of bmap
+ * @b_ops: bmap operation table
+ * @b_pops: bmap ptr operation table
+ * @b_low: low watermark of conversion
+ * @b_high: high watermark of conversion
+ * @b_last_allocated_key: last allocated key for data block
+ * @b_last_allocated_ptr: last allocated ptr for data block
+ * @b_state: state
+ */
+struct nilfs_bmap {
+	union {
+		__u8 u_flags;
+		__le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
+	} b_u;
+	struct rw_semaphore b_sem;
+	struct inode *b_inode;
+	const struct nilfs_bmap_operations *b_ops;
+	const struct nilfs_bmap_ptr_operations *b_pops;
+	__u64 b_low;
+	__u64 b_high;
+	__u64 b_last_allocated_key;
+	__u64 b_last_allocated_ptr;
+	int b_state;
+};
+
+/* state */
+#define NILFS_BMAP_DIRTY	0x00000001
+
+
+int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
+int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
+void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
+int nilfs_bmap_lookup(struct nilfs_bmap *, unsigned long, unsigned long *);
+int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
+int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
+int nilfs_bmap_last_key(struct nilfs_bmap *, unsigned long *);
+int nilfs_bmap_truncate(struct nilfs_bmap *, unsigned long);
+void nilfs_bmap_clear(struct nilfs_bmap *);
+int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
+void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
+int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
+		      unsigned long, union nilfs_binfo *);
+int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
+int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);
+
+void nilfs_bmap_init_gc(struct nilfs_bmap *);
+void nilfs_bmap_init_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
+void nilfs_bmap_commit_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
+
+
+/*
+ * Internal use only
+ */
+
+int nilfs_bmap_move_v(const struct nilfs_bmap *, __u64, sector_t);
+int nilfs_bmap_mark_dirty(const struct nilfs_bmap *, __u64);
+
+
+__u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
+			      const struct buffer_head *);
+
+__u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
+__u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);
+
+int nilfs_bmap_prepare_update(struct nilfs_bmap *,
+			      union nilfs_bmap_ptr_req *,
+			      union nilfs_bmap_ptr_req *);
+void nilfs_bmap_commit_update(struct nilfs_bmap *,
+			      union nilfs_bmap_ptr_req *,
+			      union nilfs_bmap_ptr_req *);
+void nilfs_bmap_abort_update(struct nilfs_bmap *,
+			     union nilfs_bmap_ptr_req *,
+			     union nilfs_bmap_ptr_req *);
+
+void nilfs_bmap_add_blocks(const struct nilfs_bmap *, int);
+void nilfs_bmap_sub_blocks(const struct nilfs_bmap *, int);
+
+
+int nilfs_bmap_get_block(const struct nilfs_bmap *, __u64,
+			 struct buffer_head **);
+void nilfs_bmap_put_block(const struct nilfs_bmap *, struct buffer_head *);
+int nilfs_bmap_get_new_block(const struct nilfs_bmap *, __u64,
+			     struct buffer_head **);
+void nilfs_bmap_delete_block(const struct nilfs_bmap *, struct buffer_head *);
+
+
+/* Assume that bmap semaphore is locked. */
+static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
+{
+	return !!(bmap->b_state & NILFS_BMAP_DIRTY);
+}
+
+/* Assume that bmap semaphore is locked. */
+static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
+{
+	bmap->b_state |= NILFS_BMAP_DIRTY;
+}
+
+/* Assume that bmap semaphore is locked. */
+static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
+{
+	bmap->b_state &= ~NILFS_BMAP_DIRTY;
+}
+
+
+#define NILFS_BMAP_LARGE	0x1
+
+#define NILFS_BMAP_SMALL_LOW	NILFS_DIRECT_KEY_MIN
+#define NILFS_BMAP_SMALL_HIGH	NILFS_DIRECT_KEY_MAX
+#define NILFS_BMAP_LARGE_LOW	NILFS_BTREE_ROOT_NCHILDREN_MAX
+#define NILFS_BMAP_LARGE_HIGH	NILFS_BTREE_KEY_MAX
+
+#endif	/* _NILFS_BMAP_H */