linux/fs/nilfs2/page.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Buffer/page management specific to NILFS
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * Written by Ryusuke Konishi and Seiji Kihara.
 */

#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/bitops.h>
#include <linux/page-flags.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <linux/pagevec.h>
#include <linux/gfp.h>
#include "nilfs.h"
#include "page.h"
#include "mdt.h"


#define NILFS_BUFFER_INHERENT_BITS …

static struct buffer_head *__nilfs_get_folio_block(struct folio *folio,
		unsigned long block, pgoff_t index, int blkbits,
		unsigned long b_state)

{ … }

struct buffer_head *nilfs_grab_buffer(struct inode *inode,
				      struct address_space *mapping,
				      unsigned long blkoff,
				      unsigned long b_state)
{ … }

/**
 * nilfs_forget_buffer - discard dirty state
 * @bh: buffer head of the buffer to be discarded
 */
void nilfs_forget_buffer(struct buffer_head *bh)
{ … }

/**
 * nilfs_copy_buffer -- copy buffer data and flags
 * @dbh: destination buffer
 * @sbh: source buffer
 */
void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
{ … }

/**
 * nilfs_folio_buffers_clean - Check if a folio has dirty buffers or not.
 * @folio: Folio to be checked.
 *
 * nilfs_folio_buffers_clean() returns false if the folio has dirty buffers.
 * Otherwise, it returns true.
 */
bool nilfs_folio_buffers_clean(struct folio *folio)
{ … }

void nilfs_folio_bug(struct folio *folio)
{ … }

/**
 * nilfs_copy_folio -- copy the folio with buffers
 * @dst: destination folio
 * @src: source folio
 * @copy_dirty: flag whether to copy dirty states on the folio's buffer heads.
 *
 * This function is for both data folios and btnode folios.  The dirty flag
 * should be treated by caller.  The folio must not be under i/o.
 * Both src and dst folio must be locked
 */
static void nilfs_copy_folio(struct folio *dst, struct folio *src,
		bool copy_dirty)
{ … }

int nilfs_copy_dirty_pages(struct address_space *dmap,
			   struct address_space *smap)
{ … }

/**
 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
 * @dmap: destination page cache
 * @smap: source page cache
 *
 * No pages must be added to the cache during this process.
 * This must be ensured by the caller.
 */
void nilfs_copy_back_pages(struct address_space *dmap,
			   struct address_space *smap)
{ … }

/**
 * nilfs_clear_dirty_pages - discard dirty pages in address space
 * @mapping: address space with dirty pages for discarding
 * @silent: suppress [true] or print [false] warning messages
 */
void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
{ … }

/**
 * nilfs_clear_folio_dirty - discard dirty folio
 * @folio: dirty folio that will be discarded
 * @silent: suppress [true] or print [false] warning messages
 */
void nilfs_clear_folio_dirty(struct folio *folio, bool silent)
{ … }

unsigned int nilfs_page_count_clean_buffers(struct page *page,
					    unsigned int from, unsigned int to)
{ … }

/*
 * NILFS2 needs clear_page_dirty() in the following two cases:
 *
 * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
 *    flag of pages when it copies back pages from shadow cache to the
 *    original cache.
 *
 * 2) Some B-tree operations like insertion or deletion may dispose buffers
 *    in dirty state, and this needs to cancel the dirty state of their pages.
 */
void __nilfs_clear_folio_dirty(struct folio *folio)
{ … }

/**
 * nilfs_find_uncommitted_extent - find extent of uncommitted data
 * @inode: inode
 * @start_blk: start block offset (in)
 * @blkoff: start offset of the found extent (out)
 *
 * This function searches an extent of buffers marked "delayed" which
 * starts from a block offset equal to or larger than @start_blk.  If
 * such an extent was found, this will store the start offset in
 * @blkoff and return its length in blocks.  Otherwise, zero is
 * returned.
 */
unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
					    sector_t start_blk,
					    sector_t *blkoff)
{ … }