// SPDX-License-Identifier: GPL-2.0 /* * linux/fs/ext4/resize.c * * Support for resizing an ext4 filesystem while it is mounted. * * Copyright (C) 2001, 2002 Andreas Dilger <[email protected]> * * This could probably be made into a module, because it is not often in use. */ #include <linux/errno.h> #include <linux/slab.h> #include <linux/jiffies.h> #include "ext4_jbd2.h" struct ext4_rcu_ptr { … }; static void ext4_rcu_ptr_callback(struct rcu_head *head) { … } void ext4_kvfree_array_rcu(void *to_free) { … } int ext4_resize_begin(struct super_block *sb) { … } int ext4_resize_end(struct super_block *sb, bool update_backups) { … } static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb, ext4_group_t group) { … } #define outside(b, first, last) … #define inside(b, first, last) … static int verify_group_input(struct super_block *sb, struct ext4_new_group_data *input) { … } /* * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex * group each time. */ struct ext4_new_flex_group_data { … }; /* * Avoiding memory allocation failures due to too many groups added each time. */ #define MAX_RESIZE_BG … /* * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of * @flexbg_size. * * Returns NULL on failure otherwise address of the allocated structure. */ static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size, ext4_group_t o_group, ext4_group_t n_group) { … } static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd) { … } /* * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps * and inode tables for a flex group. * * This function is used by 64bit-resize. Note that this function allocates * group tables from the 1st group of groups contained by @flexgd, which may * be a partial of a flex group. * * @sb: super block of fs to which the groups belongs * * Returns 0 on a successful allocation of the metadata blocks in the * block group. */ static int ext4_alloc_group_tables(struct super_block *sb, struct ext4_new_flex_group_data *flex_gd, unsigned int flexbg_size) { … } static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, ext4_fsblk_t blk) { … } static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits) { … } /* * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used. * * Helper function for ext4_setup_new_group_blocks() which set . * * @sb: super block * @handle: journal handle * @flex_gd: flex group data */ static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle, struct ext4_new_flex_group_data *flex_gd, ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster) { … } /* * Set up the block and inode bitmaps, and the inode table for the new groups. * This doesn't need to be part of the main transaction, since we are only * changing blocks outside the actual filesystem. We still do journaling to * ensure the recovery is correct in case of a failure just after resize. * If any part of this fails, we simply abort the resize. * * setup_new_flex_group_blocks handles a flex group as follow: * 1. copy super block and GDT, and initialize group tables if necessary. * In this step, we only set bits in blocks bitmaps for blocks taken by * super block and GDT. * 2. allocate group tables in block bitmaps, that is, set bits in block * bitmap for blocks taken by group tables. */ static int setup_new_flex_group_blocks(struct super_block *sb, struct ext4_new_flex_group_data *flex_gd) { … } /* * Iterate through the groups which hold BACKUP superblock/GDT copies in an * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before * calling this for the first time. In a sparse filesystem it will be the * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... */ unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three, unsigned int *five, unsigned int *seven) { … } /* * Check that all of the backup GDT blocks are held in the primary GDT block. * It is assumed that they are stored in group order. Returns the number of * groups in current filesystem that have BACKUPS, or -ve error code. */ static int verify_reserved_gdb(struct super_block *sb, ext4_group_t end, struct buffer_head *primary) { … } /* * Called when we need to bring a reserved group descriptor table block into * use from the resize inode. The primary copy of the new GDT block currently * is an indirect block (under the double indirect block in the resize inode). * The new backup GDT blocks will be stored as leaf blocks in this indirect * block, in group order. Even though we know all the block numbers we need, * we check to ensure that the resize inode has actually reserved these blocks. * * Don't need to update the block bitmaps because the blocks are still in use. * * We get all of the error cases out of the way, so that we are sure to not * fail once we start modifying the data on disk, because JBD has no rollback. */ static int add_new_gdb(handle_t *handle, struct inode *inode, ext4_group_t group) { … } /* * If there is no available space in the existing block group descriptors for * the new block group and there are no reserved block group descriptors, then * the meta_bg feature will get enabled, and es->s_first_meta_bg will get set * to the first block group that is managed using meta_bg and s_first_meta_bg * must be a multiple of EXT4_DESC_PER_BLOCK(sb). * This function will be called when first group of meta_bg is added to bring * new group descriptors block of new added meta_bg. */ static int add_new_gdb_meta_bg(struct super_block *sb, handle_t *handle, ext4_group_t group) { … } /* * Called when we are adding a new group which has a backup copy of each of * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks. * We need to add these reserved backup GDT blocks to the resize inode, so * that they are kept for future resizing and not allocated to files. * * Each reserved backup GDT block will go into a different indirect block. * The indirect blocks are actually the primary reserved GDT blocks, * so we know in advance what their block numbers are. We only get the * double-indirect block to verify it is pointing to the primary reserved * GDT blocks so we don't overwrite a data block by accident. The reserved * backup GDT blocks are stored in their reserved primary GDT block. */ static int reserve_backup_gdb(handle_t *handle, struct inode *inode, ext4_group_t group) { … } static inline void ext4_set_block_group_nr(struct super_block *sb, char *data, ext4_group_t group) { … } /* * Update the backup copies of the ext4 metadata. These don't need to be part * of the main resize transaction, because e2fsck will re-write them if there * is a problem (basically only OOM will cause a problem). However, we * _should_ update the backups if possible, in case the primary gets trashed * for some reason and we need to run e2fsck from a backup superblock. The * important part is that the new block and inode counts are in the backup * superblocks, and the location of the new group metadata in the GDT backups. * * We do not need take the s_resize_lock for this, because these * blocks are not otherwise touched by the filesystem code when it is * mounted. We don't need to worry about last changing from * sbi->s_groups_count, because the worst that can happen is that we * do not copy the full number of backups at this time. The resize * which changed s_groups_count will backup again. */ static void update_backups(struct super_block *sb, sector_t blk_off, char *data, int size, int meta_bg) { … } /* * ext4_add_new_descs() adds @count group descriptor of groups * starting at @group * * @handle: journal handle * @sb: super block * @group: the group no. of the first group desc to be added * @resize_inode: the resize inode * @count: number of group descriptors to be added */ static int ext4_add_new_descs(handle_t *handle, struct super_block *sb, ext4_group_t group, struct inode *resize_inode, ext4_group_t count) { … } static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block) { … } static int ext4_set_bitmap_checksums(struct super_block *sb, struct ext4_group_desc *gdp, struct ext4_new_group_data *group_data) { … } /* * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg */ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb, struct ext4_new_flex_group_data *flex_gd) { … } static void ext4_add_overhead(struct super_block *sb, const ext4_fsblk_t overhead) { … } /* * ext4_update_super() updates the super block so that the newly added * groups can be seen by the filesystem. * * @sb: super block * @flex_gd: new added groups */ static void ext4_update_super(struct super_block *sb, struct ext4_new_flex_group_data *flex_gd) { … } /* Add a flex group to an fs. Ensure we handle all possible error conditions * _before_ we start modifying the filesystem, because we cannot abort the * transaction and not have it write the data to disk. */ static int ext4_flex_group_add(struct super_block *sb, struct inode *resize_inode, struct ext4_new_flex_group_data *flex_gd) { … } static int ext4_setup_next_flex_gd(struct super_block *sb, struct ext4_new_flex_group_data *flex_gd, ext4_fsblk_t n_blocks_count) { … } /* Add group descriptor data to an existing or new group descriptor block. * Ensure we handle all possible error conditions _before_ we start modifying * the filesystem, because we cannot abort the transaction and not have it * write the data to disk. * * If we are on a GDT block boundary, we need to get the reserved GDT block. * Otherwise, we may need to add backup GDT blocks for a sparse group. * * We only need to hold the superblock lock while we are actually adding * in the new group's counts to the superblock. Prior to that we have * not really "added" the group at all. We re-check that we are still * adding in the last group in case things have changed since verifying. */ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) { … } /* ext4_group_add */ /* * extend a group without checking assuming that checking has been done. */ static int ext4_group_extend_no_check(struct super_block *sb, ext4_fsblk_t o_blocks_count, ext4_grpblk_t add) { … } /* * Extend the filesystem to the new number of blocks specified. This entry * point is only used to extend the current filesystem to the end of the last * existing group. It can be accessed via ioctl, or by "remount,resize=<size>" * for emergencies (because it has no dependencies on reserved blocks). * * If we _really_ wanted, we could use default values to call ext4_group_add() * allow the "remount" trick to work for arbitrary resizing, assuming enough * GDT blocks are reserved to grow to the desired size. */ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es, ext4_fsblk_t n_blocks_count) { … } /* ext4_group_extend */ static int num_desc_blocks(struct super_block *sb, ext4_group_t groups) { … } /* * Release the resize inode and drop the resize_inode feature if there * are no more reserved gdt blocks, and then convert the file system * to enable meta_bg */ static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode) { … } /* * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count * * @sb: super block of the fs to be resized * @n_blocks_count: the number of blocks resides in the resized fs */ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) { … }
Codebase Browser
linux