linux/fs/nilfs2/mdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Meta data file for NILFS
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * Written by Ryusuke Konishi.
 */

#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/mm.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include "nilfs.h"
#include "btnode.h"
#include "segment.h"
#include "page.h"
#include "mdt.h"
#include "alloc.h"		/* nilfs_palloc_destroy_cache() */

#include <trace/events/nilfs2.h>

#define NILFS_MDT_MAX_RA_BLOCKS …


static int
nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
			   struct buffer_head *bh,
			   void (*init_block)(struct inode *,
					      struct buffer_head *, void *))
{ … }

static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
				  struct buffer_head **out_bh,
				  void (*init_block)(struct inode *,
						     struct buffer_head *,
						     void *))
{ … }

static int
nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, blk_opf_t opf,
		       struct buffer_head **out_bh)
{ … }

static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
				int readahead, struct buffer_head **out_bh)
{ … }

/**
 * nilfs_mdt_get_block - read or create a buffer on meta data file.
 * @inode: inode of the meta data file
 * @blkoff: block offset
 * @create: create flag
 * @init_block: initializer used for newly allocated block
 * @out_bh: output of a pointer to the buffer_head
 *
 * nilfs_mdt_get_block() looks up the specified buffer and tries to create
 * a new buffer if @create is not zero.  On success, the returned buffer is
 * assured to be either existing or formatted using a buffer lock on success.
 * @out_bh is substituted only when zero is returned.
 *
 * Return Value: On success, it returns 0. On error, the following negative
 * error code is returned.
 *
 * %-ENOMEM - Insufficient memory available.
 *
 * %-EIO - I/O error
 *
 * %-ENOENT - the specified block does not exist (hole block)
 *
 * %-EROFS - Read only filesystem (for create mode)
 */
int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
			void (*init_block)(struct inode *,
					   struct buffer_head *, void *),
			struct buffer_head **out_bh)
{ … }

/**
 * nilfs_mdt_find_block - find and get a buffer on meta data file.
 * @inode: inode of the meta data file
 * @start: start block offset (inclusive)
 * @end: end block offset (inclusive)
 * @blkoff: block offset
 * @out_bh: place to store a pointer to buffer_head struct
 *
 * nilfs_mdt_find_block() looks up an existing block in range of
 * [@start, @end] and stores pointer to a buffer head of the block to
 * @out_bh, and block offset to @blkoff, respectively.  @out_bh and
 * @blkoff are substituted only when zero is returned.
 *
 * Return Value: On success, it returns 0. On error, the following negative
 * error code is returned.
 *
 * %-ENOMEM - Insufficient memory available.
 *
 * %-EIO - I/O error
 *
 * %-ENOENT - no block was found in the range
 */
int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
			 unsigned long end, unsigned long *blkoff,
			 struct buffer_head **out_bh)
{ … }

/**
 * nilfs_mdt_delete_block - make a hole on the meta data file.
 * @inode: inode of the meta data file
 * @block: block offset
 *
 * Return Value: On success, zero is returned.
 * On error, one of the following negative error code is returned.
 *
 * %-ENOMEM - Insufficient memory available.
 *
 * %-EIO - I/O error
 */
int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
{ … }

/**
 * nilfs_mdt_forget_block - discard dirty state and try to remove the page
 * @inode: inode of the meta data file
 * @block: block offset
 *
 * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
 * tries to release the page including the buffer from a page cache.
 *
 * Return Value: On success, 0 is returned. On error, one of the following
 * negative error code is returned.
 *
 * %-EBUSY - page has an active buffer.
 *
 * %-ENOENT - page cache has no page addressed by the offset.
 */
int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
{ … }

int nilfs_mdt_fetch_dirty(struct inode *inode)
{ … }

static int
nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
{ … }


static const struct address_space_operations def_mdt_aops = …;

static const struct inode_operations def_mdt_iops;
static const struct file_operations def_mdt_fops;


int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
{ … }

/**
 * nilfs_mdt_clear - do cleanup for the metadata file
 * @inode: inode of the metadata file
 */
void nilfs_mdt_clear(struct inode *inode)
{ … }

/**
 * nilfs_mdt_destroy - release resources used by the metadata file
 * @inode: inode of the metadata file
 */
void nilfs_mdt_destroy(struct inode *inode)
{ … }

void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
			      unsigned int header_size)
{ … }

/**
 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
 * @inode: inode of the metadata file
 * @shadow: shadow mapping
 */
int nilfs_mdt_setup_shadow_map(struct inode *inode,
			       struct nilfs_shadow_map *shadow)
{ … }

/**
 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
 * @inode: inode of the metadata file
 */
int nilfs_mdt_save_to_shadow_map(struct inode *inode)
{ … }

int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
{ … }

struct buffer_head *
nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
{ … }

static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
{ … }

/**
 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
 * @inode: inode of the metadata file
 */
void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
{ … }

/**
 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
 * @inode: inode of the metadata file
 */
void nilfs_mdt_clear_shadow_map(struct inode *inode)
{ … }