linux/fs/ext4/fsmap.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 Oracle.  All Rights Reserved.
 *
 * Author: Darrick J. Wong <[email protected]>
 */
#include "ext4.h"
#include <linux/fsmap.h>
#include "fsmap.h"
#include "mballoc.h"
#include <linux/sort.h>
#include <linux/list_sort.h>
#include <trace/events/ext4.h>

/* Convert an ext4_fsmap to an fsmap. */
void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
			      struct ext4_fsmap *src)
{ … }

/* Convert an fsmap to an ext4_fsmap. */
void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
			    struct fsmap *src)
{ … }

/* getfsmap query state */
struct ext4_getfsmap_info { … };

/* Associate a device with a getfsmap handler. */
struct ext4_getfsmap_dev { … };

/* Compare two getfsmap device handlers. */
static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
{ … }

/* Compare a record against our starting point */
static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
					     struct ext4_fsmap *rec)
{ … }

/*
 * Format a reverse mapping for getfsmap, having translated rm_startblock
 * into the appropriate daddr units.
 */
static int ext4_getfsmap_helper(struct super_block *sb,
				struct ext4_getfsmap_info *info,
				struct ext4_fsmap *rec)
{ … }

static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
{ … }

/* Transform a blockgroup's free record into a fsmap */
static int ext4_getfsmap_datadev_helper(struct super_block *sb,
					ext4_group_t agno, ext4_grpblk_t start,
					ext4_grpblk_t len, void *priv)
{ … }

/* Execute a getfsmap query against the log device. */
static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
				struct ext4_getfsmap_info *info)
{ … }

/* Helper to fill out an ext4_fsmap. */
static inline int ext4_getfsmap_fill(struct list_head *meta_list,
				     ext4_fsblk_t fsb, ext4_fsblk_t len,
				     uint64_t owner)
{ … }

/*
 * This function returns the number of file system metadata blocks at
 * the beginning of a block group, including the reserved gdt blocks.
 */
static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
					  ext4_group_t agno,
					  struct list_head *meta_list)
{ … }

/* Compare two fsmap items. */
static int ext4_getfsmap_compare(void *priv,
				 const struct list_head *a,
				 const struct list_head *b)
{ … }

/* Merge adjacent extents of fixed metadata. */
static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
{ … }

/* Free a list of fixed metadata. */
static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
{ … }

/* Find all the fixed metadata in the filesystem. */
static int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
					     struct list_head *meta_list)
{ … }

/* Execute a getfsmap query against the buddy bitmaps */
static int ext4_getfsmap_datadev(struct super_block *sb,
				 struct ext4_fsmap *keys,
				 struct ext4_getfsmap_info *info)
{ … }

/* Do we recognize the device? */
static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
					  struct ext4_fsmap *fm)
{ … }

/* Ensure that the low key is less than the high key. */
static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
				     struct ext4_fsmap *high_key)
{ … }

#define EXT4_GETFSMAP_DEVS …
/*
 * Get filesystem's extents as described in head, and format for
 * output.  Calls formatter to fill the user's buffer until all
 * extents are mapped, until the passed-in head->fmh_count slots have
 * been filled, or until the formatter short-circuits the loop, if it
 * is tracking filled-in extents on its own.
 *
 * Key to Confusion
 * ----------------
 * There are multiple levels of keys and counters at work here:
 * _fsmap_head.fmh_keys		-- low and high fsmap keys passed in;
 * 				   these reflect fs-wide block addrs.
 * dkeys			-- fmh_keys used to query each device;
 * 				   these are fmh_keys but w/ the low key
 * 				   bumped up by fmr_length.
 * _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
 *				   is how we detect gaps in the fsmap
 *				   records and report them.
 * _getfsmap_info.gfi_low/high	-- per-bg low/high keys computed from
 * 				   dkeys; used to query the free space.
 */
int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
		  ext4_fsmap_format_t formatter, void *arg)
{ … }