// SPDX-License-Identifier: GPL-2.0 /* * linux/fs/ext4/balloc.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card ([email protected]) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * Enhanced block allocation by Stephen Tweedie ([email protected]), 1993 * Big-endian to little-endian byte-swapping/bitmaps by * David S. Miller ([email protected]), 1995 */ #include <linux/time.h> #include <linux/capability.h> #include <linux/fs.h> #include <linux/quotaops.h> #include <linux/buffer_head.h> #include "ext4.h" #include "ext4_jbd2.h" #include "mballoc.h" #include <trace/events/ext4.h> #include <kunit/static_stub.h> static unsigned ext4_num_base_meta_clusters(struct super_block *sb, ext4_group_t block_group); /* * balloc.c contains the blocks allocation and deallocation routines */ /* * Calculate block group number for a given block number */ ext4_group_t ext4_get_group_number(struct super_block *sb, ext4_fsblk_t block) { … } /* * Calculate the block group number and offset into the block/cluster * allocation bitmap, given a block number */ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) { … } /* * Check whether the 'block' lives within the 'block_group'. Returns 1 if so * and 0 otherwise. */ static inline int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, ext4_group_t block_group) { … } /* * Return the number of clusters used for file system metadata; this * represents the overhead needed by the file system. */ static unsigned ext4_num_overhead_clusters(struct super_block *sb, ext4_group_t block_group, struct ext4_group_desc *gdp) { … } static unsigned int num_clusters_in_group(struct super_block *sb, ext4_group_t block_group) { … } /* Initializes an uninitialized block bitmap */ static int ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, ext4_group_t block_group, struct ext4_group_desc *gdp) { … } /* Return the number of free blocks in a block group. It is used when * the block bitmap is uninitialized, so we can't just count the bits * in the bitmap. */ unsigned ext4_free_clusters_after_init(struct super_block *sb, ext4_group_t block_group, struct ext4_group_desc *gdp) { … } /* * The free blocks are managed by bitmaps. A file system contains several * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap * block for inodes, N blocks for the inode table and data blocks. * * The file system contains group descriptors which are located after the * super block. Each descriptor contains the number of the bitmap block and * the free blocks count in the block. The descriptors are loaded in memory * when a file system is mounted (see ext4_fill_super). */ /** * ext4_get_group_desc() -- load group descriptor from disk * @sb: super block * @block_group: given block group * @bh: pointer to the buffer head to store the block * group descriptor */ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, ext4_group_t block_group, struct buffer_head **bh) { … } static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb, ext4_group_t block_group, struct buffer_head *bh) { … } struct ext4_group_info *ext4_get_group_info(struct super_block *sb, ext4_group_t group) { … } /* * Return the block number which was discovered to be invalid, or 0 if * the block bitmap is valid. */ static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, struct ext4_group_desc *desc, ext4_group_t block_group, struct buffer_head *bh) { … } static int ext4_validate_block_bitmap(struct super_block *sb, struct ext4_group_desc *desc, ext4_group_t block_group, struct buffer_head *bh) { … } /** * ext4_read_block_bitmap_nowait() * @sb: super block * @block_group: given block group * @ignore_locked: ignore locked buffers * * Read the bitmap for a given block_group,and validate the * bits for block/inode/inode tables are set in the bitmaps * * Return buffer_head on success or an ERR_PTR in case of failure. */ struct buffer_head * ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, bool ignore_locked) { … } /* Returns 0 on success, -errno on error */ int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, struct buffer_head *bh) { … } struct buffer_head * ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) { … } /** * ext4_has_free_clusters() * @sbi: in-core super block structure. * @nclusters: number of needed blocks * @flags: flags from ext4_mb_new_blocks() * * Check if filesystem has nclusters free & available for allocation. * On success return 1, return 0 on failure. */ static int ext4_has_free_clusters(struct ext4_sb_info *sbi, s64 nclusters, unsigned int flags) { … } int ext4_claim_free_clusters(struct ext4_sb_info *sbi, s64 nclusters, unsigned int flags) { … } /** * ext4_should_retry_alloc() - check if a block allocation should be retried * @sb: superblock * @retries: number of retry attempts made so far * * ext4_should_retry_alloc() is called when ENOSPC is returned while * attempting to allocate blocks. If there's an indication that a pending * journal transaction might free some space and allow another attempt to * succeed, this function will wait for the current or committing transaction * to complete and then return TRUE. */ int ext4_should_retry_alloc(struct super_block *sb, int *retries) { … } /* * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks * * @handle: handle to this transaction * @inode: file inode * @goal: given target block(filesystem wide) * @count: pointer to total number of clusters needed * @errp: error code * * Return 1st allocated block number on success, *count stores total account * error stores in errp pointer */ ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, ext4_fsblk_t goal, unsigned int flags, unsigned long *count, int *errp) { … } /** * ext4_count_free_clusters() -- count filesystem free clusters * @sb: superblock * * Adds up the number of free clusters from each block group. */ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) { … } static inline int test_root(ext4_group_t a, int b) { … } /** * ext4_bg_has_super - number of blocks used by the superblock in group * @sb: superblock for filesystem * @group: group number to check * * Return the number of blocks used by the superblock (primary or backup) * in this group. Currently this will be only 0 or 1. */ int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) { … } static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, ext4_group_t group) { … } static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, ext4_group_t group) { … } /** * ext4_bg_num_gdb - number of blocks used by the group table in group * @sb: superblock for filesystem * @group: group number to check * * Return the number of blocks used by the group descriptor table * (primary or backup) in this group. In the future there may be a * different number of descriptor blocks in each group. */ unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) { … } /* * This function returns the number of file system metadata blocks at * the beginning of a block group, including the reserved gdt blocks. */ unsigned int ext4_num_base_meta_blocks(struct super_block *sb, ext4_group_t block_group) { … } static unsigned int ext4_num_base_meta_clusters(struct super_block *sb, ext4_group_t block_group) { … } /** * ext4_inode_to_goal_block - return a hint for block allocation * @inode: inode for block allocation * * Return the ideal location to start allocating blocks for a * newly created inode. */ ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) { … }
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