linux/fs/jbd2/commit.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * linux/fs/jbd2/commit.c
 *
 * Written by Stephen C. Tweedie <[email protected]>, 1998
 *
 * Copyright 1998 Red Hat corp --- All Rights Reserved
 *
 * Journal commit routines for the generic filesystem journaling code;
 * part of the ext2fs journaling system.
 */

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/crc32.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/bitops.h>
#include <trace/events/jbd2.h>

/*
 * IO end handler for temporary buffer_heads handling writes to the journal.
 */
static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
{ … }

/*
 * When an ext4 file is truncated, it is possible that some pages are not
 * successfully freed, because they are attached to a committing transaction.
 * After the transaction commits, these pages are left on the LRU, with no
 * ->mapping, and with attached buffers.  These pages are trivially reclaimable
 * by the VM, but their apparent absence upsets the VM accounting, and it makes
 * the numbers in /proc/meminfo look odd.
 *
 * So here, we have a buffer which has just come off the forget list.  Look to
 * see if we can strip all buffers from the backing page.
 *
 * Called under lock_journal(), and possibly under journal_datalist_lock.  The
 * caller provided us with a ref against the buffer, and we drop that here.
 */
static void release_buffer_page(struct buffer_head *bh)
{ … }

static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
{ … }

/*
 * Done it all: now submit the commit record.  We should have
 * cleaned up our previous buffers by now, so if we are in abort
 * mode we can now just skip the rest of the journal write
 * entirely.
 *
 * Returns 1 if the journal needs to be aborted or 0 on success
 */
static int journal_submit_commit_record(journal_t *journal,
					transaction_t *commit_transaction,
					struct buffer_head **cbh,
					__u32 crc32_sum)
{ … }

/*
 * This function along with journal_submit_commit_record
 * allows to write the commit record asynchronously.
 */
static int journal_wait_on_commit_record(journal_t *journal,
					 struct buffer_head *bh)
{ … }

/* Send all the data buffers related to an inode */
int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
{ … }
EXPORT_SYMBOL(…);

int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
{ … }
EXPORT_SYMBOL(…);

/*
 * Submit all the data buffers of inode associated with the transaction to
 * disk.
 *
 * We are in a committing transaction. Therefore no new inode can be added to
 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
 * operate on from being released while we write out pages.
 */
static int journal_submit_data_buffers(journal_t *journal,
		transaction_t *commit_transaction)
{ … }

int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
{ … }

/*
 * Wait for data submitted for writeout, refile inodes to proper
 * transaction if needed.
 *
 */
static int journal_finish_inode_data_buffers(journal_t *journal,
		transaction_t *commit_transaction)
{ … }

static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
{ … }

static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
				   unsigned long long block)
{ … }

static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
				    struct buffer_head *bh, __u32 sequence)
{ … }
/*
 * jbd2_journal_commit_transaction
 *
 * The primary function for committing a transaction to the log.  This
 * function is called by the journal thread to begin a complete commit.
 */
void jbd2_journal_commit_transaction(journal_t *journal)
{ … }