path: root/fs/gfs2/aops.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/mpage.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/gfs2_ondisk.h>
#include <linux/backing-dev.h>
#include <linux/uio.h>
#include <trace/events/writeback.h>
#include <linux/sched/signal.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "meta_io.h"
#include "quota.h"
#include "trans.h"
#include "rgrp.h"
#include "super.h"
#include "util.h"
#include "glops.h"
#include "aops.h"


void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
			    unsigned int from, unsigned int len)
{
	struct buffer_head *head = page_buffers(page);
	unsigned int bsize = head->b_size;
	struct buffer_head *bh;
	unsigned int to = from + len;
	unsigned int start, end;

	for (bh = head, start = 0; bh != head || !start;
	     bh = bh->b_this_page, start = end) {
		end = start + bsize;
		if (end <= from)
			continue;
		if (start >= to)
			break;
		set_buffer_uptodate(bh);
		gfs2_trans_add_data(ip->i_gl, bh);
	}
}

/**
 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
 * @inode: The inode
 * @lblock: The block number to look up
 * @bh_result: The buffer head to return the result in
 * @create: Non-zero if we may add block to the file
 *
 * Returns: errno
 */

static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
				  struct buffer_head *bh_result, int create)
{
	int error;

	error = gfs2_block_map(inode, lblock, bh_result, 0);
	if (error)
		return error;
	if (!buffer_mapped(bh_result))
		return -ENODATA;
	return 0;
}

/**
 * gfs2_writepage - Write page for writeback mappings
 * @page: The page
 * @wbc: The writeback control
 */
static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	struct iomap_writepage_ctx wpc = { };

	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
		goto out;
	if (current->journal_info)
		goto redirty;
	return iomap_writepage(page, wbc, &wpc, &gfs2_writeback_ops);

redirty:
	redirty_page_for_writepage(wbc, page);
out:
	unlock_page(page);
	return 0;
}

/**
 * gfs2_write_jdata_page - gfs2 jdata-specific version of block_write_full_page
 * @page: The page to write
 * @wbc: The writeback control
 *
 * This is the same as calling block_write_full_page, but it also
 * writes pages outside of i_size
 */
static int gfs2_write_jdata_page(struct page *page,
				 struct writeback_control *wbc)
{
	struct inode * const inode = page->mapping->host;
	loff_t i_size = i_size_read(inode);
	const pgoff_t end_index = i_size >> PAGE_SHIFT;
	unsigned offset;

	/*
	 * The page straddles i_size.  It must be zeroed out on each and every
	 * writepage invocation because it may be mmapped.  "A file is mapped
	 * in multiples of the page size.  For a file that is not a multiple of
	 * the  page size, the remaining memory is zeroed when mapped, and
	 * writes to that region are not written out to the file."
	 */
	offset = i_size & (PAGE_SIZE - 1);
	if (page->index == end_index && offset)
		zero_user_segment(page, offset, PAGE_SIZE);

	return __block_write_full_page(inode, page, gfs2_get_block_noalloc, wbc,
				       end_buffer_async_write);
}

/**
 * __gfs2_jdata_writepage - The core of jdata writepage
 * @page: The page to write
 * @wbc: The writeback control
 *
 * This is shared between writepage and writepages and implements the
 * core of the writepage operation. If a transaction is required then
 * PageChecked will have been set and the transaction will have
 * already been started before this is called.
 */

static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);

	if (PageChecked(page)) {
		ClearPageChecked(page);
		if (!page_has_buffers(page)) {
			create_empty_buffers(page, inode->i_sb->s_blocksize,
					     BIT(BH_Dirty)|BIT(BH_Uptodate));
		}
		gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
	}
	return gfs2_write_jdata_page(page, wbc);
}

/**
 * gfs2_jdata_writepage - Write complete page
 * @page: Page to write
 * @wbc: The writeback control
 *
 * Returns: errno
 *
 */

static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
{
	struct inode *inode = page->mapping->host;
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);

	if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
		goto out;
	if (PageChecked(page) || current->journal_info)
		goto out_ignore;
	return __gfs2_jdata_writepage(page, wbc);

out_ignore:
	redirty_page_for_writepage(wbc, page);
out:
	unlock_page(page);
	return 0;
}

/**
 * gfs2_writepages - Write a bunch of dirty pages back to disk
 * @mapping: The mapping to write
 * @wbc: Write-back control
 *
 * Used for both ordered and writeback modes.
 */
static int gfs2_writepages(struct address_space