xfs_log_rlimit.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2013 Jie Liu.
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_trans_space.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_trace.h"

/*
 * Shortly after enabling the large extents count feature in 2023, longstanding
 * bugs were found in the code that computes the minimum log size.  Luckily,
 * the bugs resulted in over-estimates of that size, so there's no impact to
 * existing users.  However, we don't want to reduce the minimum log size
 * because that can create the situation where a newer mkfs writes a new
 * filesystem that an older kernel won't mount.
 *
 * Several years prior, we also discovered that the transaction reservations
 * for rmap and reflink operations were unnecessarily large.  That was fixed,
 * but the minimum log size computation was left alone to avoid the
 * compatibility problems noted above.  Fix that too.
 *
 * Therefore, we only may correct the computation starting with filesystem
 * features that didn't exist in 2023.  In other words, only turn this on if
 * the filesystem has parent pointers.
 *
 * This function can be called before the XFS_HAS_* flags have been set up,
 * (e.g. mkfs) so we must check the ondisk superblock.
 */
static inline bool
xfs_want_minlogsize_fixes(
	struct xfs_sb	*sb)
{ … }

/*
 * Calculate the maximum length in bytes that would be required for a local
 * attribute value as large attributes out of line are not logged.
 */
STATIC int
xfs_log_calc_max_attrsetm_res(
	struct xfs_mount	*mp)
{ … }

/*
 * Compute an alternate set of log reservation sizes for use exclusively with
 * minimum log size calculations.
 */
static void
xfs_log_calc_trans_resv_for_minlogblocks(
	struct xfs_mount	*mp,
	struct xfs_trans_resv	*resv)
{ … }

/*
 * Iterate over the log space reservation table to figure out and return
 * the maximum one in terms of the pre-calculated values which were done
 * at mount time.
 */
void
xfs_log_get_max_trans_res(
	struct xfs_mount	*mp,
	struct xfs_trans_res	*max_resp)
{ … }

/*
 * Calculate the minimum valid log size for the given superblock configuration.
 * Used to calculate the minimum log size at mkfs time, and to determine if
 * the log is large enough or not at mount time. Returns the minimum size in
 * filesystem block size units.
 */
int
xfs_log_calc_minimum_size(
	struct xfs_mount	*mp)
{ … }
linux/fs/xfs/libxfs/xfs_log_rlimit.c
