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resize.c
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// 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.
*/
#define EXT4FS_DEBUG
#include <linux/errno.h>
#include <linux/slab.h>
#include "ext4_jbd2.h"
struct ext4_rcu_ptr {
struct rcu_head rcu;
void *ptr;
};
static void ext4_rcu_ptr_callback(struct rcu_head *head)
{
struct ext4_rcu_ptr *ptr;
ptr = container_of(head, struct ext4_rcu_ptr, rcu);
kvfree(ptr->ptr);
kfree(ptr);
}
void ext4_kvfree_array_rcu(void *to_free)
{
struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
if (ptr) {
ptr->ptr = to_free;
call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
return;
}
synchronize_rcu();
kvfree(to_free);
}
int ext4_resize_begin(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
int ret = 0;
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
/*
* If we are not using the primary superblock/GDT copy don't resize,
* because the user tools have no way of handling this. Probably a
* bad time to do it anyways.
*/
if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
ext4_warning(sb, "won't resize using backup superblock at %llu",
(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
return -EPERM;
}
/*
* We are not allowed to do online-resizing on a filesystem mounted
* with error, because it can destroy the filesystem easily.
*/
if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
ext4_warning(sb, "There are errors in the filesystem, "
"so online resizing is not allowed");
return -EPERM;
}
if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
&EXT4_SB(sb)->s_ext4_flags))
ret = -EBUSY;
return ret;
}
void ext4_resize_end(struct super_block *sb)
{
clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
smp_mb__after_atomic();
}
static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
ext4_group_t group) {
return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
}
static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
ext4_group_t group) {
group = ext4_meta_bg_first_group(sb, group);
return ext4_group_first_block_no(sb, group);
}
static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
ext4_group_t group) {
ext4_grpblk_t overhead;
overhead = ext4_bg_num_gdb(sb, group);
if (ext4_bg_has_super(sb, group))
overhead += 1 +
le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
return overhead;
}
#define outside(b, first, last) ((b) < (first) || (b) >= (last))
#define inside(b, first, last) ((b) >= (first) && (b) < (last))
static int verify_group_input(struct super_block *sb,
struct ext4_new_group_data *input)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_fsblk_t start = ext4_blocks_count(es);
ext4_fsblk_t end = start + input->blocks_count;
ext4_group_t group = input->group;
ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
unsigned overhead;
ext4_fsblk_t metaend;
struct buffer_head *bh = NULL;
ext4_grpblk_t free_blocks_count, offset;
int err = -EINVAL;
if (group != sbi->s_groups_count) {
ext4_warning(sb, "Cannot add at group %u (only %u groups)",
input->group, sbi->s_groups_count);
return -EINVAL;
}
overhead = ext4_group_overhead_blocks(sb, group);
metaend = start + overhead;
input->free_clusters_count = free_blocks_count =
input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
"(%d free, %u reserved)\n",
ext4_bg_has_super(sb, input->group) ? "normal" :
"no-super", input->group, input->blocks_count,
free_blocks_count, input->reserved_blocks);
ext4_get_group_no_and_offset(sb, start, NULL, &offset);
if (offset != 0)
ext4_warning(sb, "Last group not full");
else if (input->reserved_blocks > input->blocks_count / 5)
ext4_warning(sb, "Reserved blocks too high (%u)",
input->reserved_blocks);
else if (free_blocks_count < 0)
ext4_warning(sb, "Bad blocks count %u",
input->blocks_count);
else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
err = PTR_ERR(bh);
bh = NULL;
ext4_warning(sb, "Cannot read last block (%llu)",
end - 1);
} else if (outside(input->block_bitmap, start, end))
ext4_warning(sb, "Block bitmap not in group (block %llu)",
(unsigned long long)input->block_bitmap);
else if (outside(input->inode_bitmap, start, end))
ext4_warning(sb, "Inode bitmap not in group (block %llu)",
(unsigned long long)input->inode_bitmap);
else if (outside(input->inode_table, start, end) ||
outside(itend - 1, start, end))
ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
(unsigned long long)input->inode_table, itend - 1);
else if (input->inode_bitmap == input->block_bitmap)
ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
(unsigned long long)input->block_bitmap);
else if (inside(input->block_bitmap, input->inode_table, itend))
ext4_warning(sb, "Block bitmap (%llu) in inode table "
"(%llu-%llu)",
(unsigned long long)input->block_bitmap,
(unsigned long long)input->inode_table, itend - 1);
else if (inside(input->inode_bitmap, input->inode_table, itend))
ext4_warning(sb, "Inode bitmap (%llu) in inode table "
"(%llu-%llu)",
(unsigned long long)input->inode_bitmap,
(unsigned long long)input->inode_table, itend - 1);
else if (inside(input->block_bitmap, start, metaend))
ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
(unsigned long long)input->block_bitmap,
start, metaend - 1);
else if (inside(input->inode_bitmap, start, metaend))
ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
(unsigned long long)input->inode_bitmap,
start, metaend - 1);
else if (inside(input->inode_table, start, metaend) ||
inside(itend - 1, start, metaend))
ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
"(%llu-%llu)",
(unsigned long long)input->inode_table,
itend - 1, start, metaend - 1);
else
err = 0;
brelse(bh);
return err;
}
/*
* ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
* group each time.
*/
struct ext4_new_flex_group_data {
struct ext4_new_group_data *groups; /* new_group_data for groups
in the flex group */
__u16 *bg_flags; /* block group flags of groups
in @groups */
ext4_group_t count; /* number of groups in @groups
*/
};
/*
* 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 long flexbg_size)
{
struct ext4_new_flex_group_data *flex_gd;
flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
if (flex_gd == NULL)
goto out3;
if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
goto out2;
flex_gd->count = flexbg_size;
flex_gd->groups = kmalloc_array(flexbg_size,
sizeof(struct ext4_new_group_data),
GFP_NOFS);
if (flex_gd->groups == NULL)
goto out2;
flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
GFP_NOFS);
if (flex_gd->bg_flags == NULL)
goto out1;
return flex_gd;
out1:
kfree(flex_gd->groups);
out2:
kfree(flex_gd);
out3:
return NULL;
}
static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
{
kfree(flex_gd->bg_flags);
kfree(flex_gd->groups);
kfree(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,
int flexbg_size)
{
struct ext4_new_group_data *group_data = flex_gd->groups;
ext4_fsblk_t start_blk;
ext4_fsblk_t last_blk;
ext4_group_t src_group;
ext4_group_t bb_index = 0;
ext4_group_t ib_index = 0;
ext4_group_t it_index = 0;
ext4_group_t group;
ext4_group_t last_group;
unsigned overhead;
__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
int i;
BUG_ON(flex_gd->count == 0 || group_data == NULL);
src_group = group_data[0].group;
last_group = src_group + flex_gd->count - 1;
BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
(last_group & ~(flexbg_size - 1))));
next_group:
group = group_data[0].group;
if (src_group >= group_data[0].group + flex_gd->count)
return -ENOSPC;
start_blk = ext4_group_first_block_no(sb, src_group);
last_blk = start_blk + group_data[src_group - group].blocks_count;
overhead = ext4_group_overhead_blocks(sb, src_group);
start_blk += overhead;
/* We collect contiguous blocks as much as possible. */
src_group++;
for (; src_group <= last_group; src_group++) {
overhead = ext4_group_overhead_blocks(sb, src_group);
if (overhead == 0)
last_blk += group_data[src_group - group].blocks_count;
else
break;
}
/* Allocate block bitmaps */
for (; bb_index < flex_gd->count; bb_index++) {
if (start_blk >= last_blk)
goto next_group;
group_data[bb_index].block_bitmap = start_blk++;
group = ext4_get_group_number(sb, start_blk - 1);
group -= group_data[0].group;
group_data[group].mdata_blocks++;
flex_gd->bg_flags[group] &= uninit_mask;
}
/* Allocate inode bitmaps */
for (; ib_index < flex_gd->count; ib_index++) {
if (start_blk >= last_blk)
goto next_group;
group_data[ib_index].inode_bitmap = start_blk++;
group = ext4_get_group_number(sb, start_blk - 1);
group -= group_data[0].group;
group_data[group].mdata_blocks++;
flex_gd->bg_flags[group] &= uninit_mask;
}
/* Allocate inode tables */
for (; it_index < flex_gd->count; it_index++) {
unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
ext4_fsblk_t next_group_start;
if (start_blk + itb > last_blk)
goto next_group;
group_data[it_index].inode_table = start_blk;
group = ext4_get_group_number(sb, start_blk);
next_group_start = ext4_group_first_block_no(sb, group + 1);
group -= group_data[0].group;
if (start_blk + itb > next_group_start) {
flex_gd->bg_flags[group + 1] &= uninit_mask;
overhead = start_blk + itb - next_group_start;
group_data[group + 1].mdata_blocks += overhead;
itb -= overhead;
}
group_data[group].mdata_blocks += itb;
flex_gd->bg_flags[group] &= uninit_mask;
start_blk += EXT4_SB(sb)->s_itb_per_group;
}
/* Update free clusters count to exclude metadata blocks */
for (i = 0; i < flex_gd->count; i++) {
group_data[i].free_clusters_count -=
EXT4_NUM_B2C(EXT4_SB(sb),
group_data[i].mdata_blocks);
}
if (test_opt(sb, DEBUG)) {
int i;
group = group_data[0].group;
printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
"%d groups, flexbg size is %d:\n", flex_gd->count,
flexbg_size);
for (i = 0; i < flex_gd->count; i++) {
ext4_debug(
"adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
ext4_bg_has_super(sb, group + i) ? "normal" :
"no-super", group + i,
group_data[i].blocks_count,
group_data[i].free_clusters_count,
group_data[i].mdata_blocks);
}
}
return 0;
}
static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
ext4_fsblk_t blk)
{
struct buffer_head *bh;
int err;
bh = sb_getblk(sb, blk);
if (unlikely(!bh))
return ERR_PTR(-ENOMEM);
BUFFER_TRACE(bh, "get_write_access");
if ((err = ext4_journal_get_write_access(handle, bh))) {
brelse(bh);
bh = ERR_PTR(err);
} else {
memset(bh->b_data, 0, sb->s_blocksize);
set_buffer_uptodate(bh);
}
return bh;
}
static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
{
return ext4_journal_ensure_credits_fn(handle, credits,
EXT4_MAX_TRANS_DATA, 0, 0);
}
/*
* 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)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t count = last_cluster - first_cluster + 1;
ext4_group_t count2;
ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
last_cluster);
for (count2 = count; count > 0;
count -= count2, first_cluster += count2) {
ext4_fsblk_t start;
struct buffer_head *bh;
ext4_group_t group;
int err;
group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
group -= flex_gd->groups[0].group;
count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
if (count2 > count)
count2 = count;
if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
BUG_ON(flex_gd->count > 1);
continue;
}
err = ext4_resize_ensure_credits_batch(handle, 1);
if (err < 0)
return err;
bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
if (unlikely(!bh))
return -ENOMEM;
BUFFER_TRACE(bh, "get_write_access");
err = ext4_journal_get_write_access(handle, bh);
if (err) {
brelse(bh);
return err;
}
ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
first_cluster, first_cluster - start, count2);
ext4_set_bits(bh->b_data, first_cluster - start, count2);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
brelse(bh);
if (unlikely(err))
return err;
}
return 0;
}
/*
* 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)
{
int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
ext4_fsblk_t start;
ext4_fsblk_t block;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
struct ext4_new_group_data *group_data = flex_gd->groups;
__u16 *bg_flags = flex_gd->bg_flags;
handle_t *handle;
ext4_group_t group, count;
struct buffer_head *bh = NULL;
int reserved_gdb, i, j, err = 0, err2;
int meta_bg;
BUG_ON(!flex_gd->count || !group_data ||
group_data[0].group != sbi->s_groups_count);
reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
meta_bg = ext4_has_feature_meta_bg(sb);
/* This transaction may be extended/restarted along the way */
handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
if (IS_ERR(handle))
return PTR_ERR(handle);
group = group_data[0].group;
for (i = 0; i < flex_gd->count; i++, group++) {
unsigned long gdblocks;
ext4_grpblk_t overhead;
gdblocks = ext4_bg_num_gdb(sb, group);
start = ext4_group_first_block_no(sb, group);
if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
goto handle_itb;
if (meta_bg == 1) {
ext4_group_t first_group;
first_group = ext4_meta_bg_first_group(sb, group);
if (first_group != group + 1 &&
first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
goto handle_itb;
}
block = start + ext4_bg_has_super(sb, group);
/* Copy all of the GDT blocks into the backup in this group */
for (j = 0; j < gdblocks; j++, block++) {
struct buffer_head *gdb;
ext4_debug("update backup group %#04llx\n", block);
err = ext4_resize_ensure_credits_batch(handle, 1);
if (err < 0)
goto out;
gdb = sb_getblk(sb, block);
if (unlikely(!gdb)) {
err = -ENOMEM;
goto out;
}
BUFFER_TRACE(gdb, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb);
if (err) {
brelse(gdb);
goto out;
}
memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
s_group_desc, j)->b_data, gdb->b_size);
set_buffer_uptodate(gdb);
err = ext4_handle_dirty_metadata(handle, NULL, gdb);
if (unlikely(err)) {
brelse(gdb);
goto out;
}
brelse(gdb);
}
/* Zero out all of the reserved backup group descriptor
* table blocks
*/
if (ext4_bg_has_super(sb, group)) {
err = sb_issue_zeroout(sb, gdblocks + start + 1,
reserved_gdb, GFP_NOFS);
if (err)
goto out;
}
handle_itb:
/* Initialize group tables of the grop @group */
if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
goto handle_bb;
/* Zero out all of the inode table blocks */
block = group_data[i].inode_table;
ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
block, sbi->s_itb_per_group);
err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
GFP_NOFS);
if (err)
goto out;
handle_bb:
if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
goto handle_ib;
/* Initialize block bitmap of the @group */
block = group_data[i].block_bitmap;
err = ext4_resize_ensure_credits_batch(handle, 1);
if (err < 0)
goto out;
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
goto out;
}
overhead = ext4_group_overhead_blocks(sb, group);
if (overhead != 0) {
ext4_debug("mark backup superblock %#04llx (+0)\n",
start);
ext4_set_bits(bh->b_data, 0,
EXT4_NUM_B2C(sbi, overhead));
}
ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
sb->s_blocksize * 8, bh->b_data);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
brelse(bh);
if (err)
goto out;
handle_ib:
if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
continue;
/* Initialize inode bitmap of the @group */
block = group_data[i].inode_bitmap;
err = ext4_resize_ensure_credits_batch(handle, 1);
if (err < 0)
goto out;
/* Mark unused entries in inode bitmap used */
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
goto out;
}
ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
sb->s_blocksize * 8, bh->b_data);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
brelse(bh);
if (err)
goto out;
}
/* Mark group tables in block bitmap */
for (j = 0; j < GROUP_TABLE_COUNT; j++) {
count = group_table_count[j];
start = (&group_data[0].block_bitmap)[j];
block = start;
for (i = 1; i < flex_gd->count; i++) {
block += group_table_count[j];
if (block == (&group_data[i].block_bitmap)[j]) {
count += group_table_count[j];
continue;
}
err = set_flexbg_block_bitmap(sb, handle,
flex_gd,
EXT4_B2C(sbi, start),
EXT4_B2C(sbi,
start + count
- 1));
if (err)
goto out;
count = group_table_count[j];
start = (&group_data[i].block_bitmap)[j];
block = start;
}
if (count) {
err = set_flexbg_block_bitmap(sb, handle,
flex_gd,
EXT4_B2C(sbi, start),
EXT4_B2C(sbi,
start + count
- 1));
if (err)
goto out;
}
}
out:
err2 = ext4_journal_stop(handle);
if (err2 && !err)
err = err2;
return err;
}
/*
* 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, ...
*/
static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
unsigned *five, unsigned *seven)
{
unsigned *min = three;
int mult = 3;
unsigned ret;
if (!ext4_has_feature_sparse_super(sb)) {
ret = *min;
*min += 1;
return ret;
}
if (*five < *min) {
min = five;
mult = 5;
}
if (*seven < *min) {
min = seven;
mult = 7;
}
ret = *min;
*min *= mult;
return ret;
}
/*
* 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)
{
const ext4_fsblk_t blk = primary->b_blocknr;
unsigned three = 1;
unsigned five = 5;
unsigned seven = 7;
unsigned grp;
__le32 *p = (__le32 *)primary->b_data;
int gdbackups = 0;
while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
if (le32_to_cpu(*p++) !=
grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
ext4_warning(sb, "reserved GDT %llu"
" missing grp %d (%llu)",
blk, grp,
grp *
(ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
blk);
return -EINVAL;
}
if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
return -EFBIG;
}
return gdbackups;
}
/*
* 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)
{
struct super_block *sb = inode->i_sb;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
struct buffer_head **o_group_desc, **n_group_desc = NULL;
struct buffer_head *dind = NULL;
struct buffer_head *gdb_bh = NULL;
int gdbackups;
struct ext4_iloc iloc = { .bh = NULL };
__le32 *data;
int err;
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG
"EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
gdb_num);
gdb_bh = ext4_sb_bread(sb, gdblock, 0);
if (IS_ERR(gdb_bh))
return PTR_ERR(gdb_bh);
gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
if (gdbackups < 0) {
err = gdbackups;
goto errout;
}
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
if (IS_ERR(dind)) {
err = PTR_ERR(dind);
dind = NULL;
goto errout;
}
data = (__le32 *)dind->b_data;
if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
ext4_warning(sb, "new group %u GDT block %llu not reserved",
group, gdblock);
err = -EINVAL;
goto errout;
}
BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
if (unlikely(err))
goto errout;
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (unlikely(err))
goto errout;
BUFFER_TRACE(dind, "get_write_access");
err = ext4_journal_get_write_access(handle, dind);
if (unlikely(err))
ext4_std_error(sb, err);
/* ext4_reserve_inode_write() gets a reference on the iloc */
err = ext4_reserve_inode_write(handle, inode, &iloc);
if (unlikely(err))
goto errout;
n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
GFP_KERNEL);
if (!n_group_desc) {
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
goto errout;
}
/*
* Finally, we have all of the possible failures behind us...
*
* Remove new GDT block from inode double-indirect block and clear out
* the new GDT block for use (which also "frees" the backup GDT blocks
* from the reserved inode). We don't need to change the bitmaps for
* these blocks, because they are marked as in-use from being in the
* reserved inode, and will become GDT blocks (primary and backup).
*/
data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
err = ext4_handle_dirty_metadata(handle, NULL, dind);
if (unlikely(err)) {
ext4_std_error(sb, err);
goto errout;
}
inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
(9 - EXT4_SB(sb)->s_cluster_bits);
ext4_mark_iloc_dirty(handle, inode, &iloc);
memset(gdb_bh->b_data, 0, sb->s_blocksize);
err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
if (unlikely(err)) {
ext4_std_error(sb, err);
iloc.bh = NULL;
goto errout;
}
brelse(dind);
rcu_read_lock();
o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
memcpy(n_group_desc, o_group_desc,
EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
rcu_read_unlock();
n_group_desc[gdb_num] = gdb_bh;
rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
EXT4_SB(sb)->s_gdb_count++;
ext4_kvfree_array_rcu(o_group_desc);
le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
err = ext4_handle_dirty_super(handle, sb);
if (err)
ext4_std_error(sb, err);
return err;
errout:
kvfree(n_group_desc);
brelse(iloc.bh);
brelse(dind);
brelse(gdb_bh);
ext4_debug("leaving with error %d\n", err);
return err;
}
/*
* add_new_gdb_meta_bg is the sister of add_new_gdb.
*/
static int add_new_gdb_meta_bg(struct super_block *sb,
handle_t *handle, ext4_group_t group) {
ext4_fsblk_t gdblock;
struct buffer_head *gdb_bh;
struct buffer_head **o_group_desc, **n_group_desc;
unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
int err;
gdblock = ext4_meta_bg_first_block_no(sb, group) +
ext4_bg_has_super(sb, group);
gdb_bh = ext4_sb_bread(sb, gdblock, 0);
if (IS_ERR(gdb_bh))
return PTR_ERR(gdb_bh);
n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
GFP_KERNEL);
if (!n_group_desc) {
brelse(gdb_bh);
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
return err;
}
rcu_read_lock();
o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
memcpy(n_group_desc, o_group_desc,
EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
rcu_read_unlock();
n_group_desc[gdb_num] = gdb_bh;
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (err) {
kvfree(n_group_desc);
brelse(gdb_bh);
return err;
}
rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
EXT4_SB(sb)->s_gdb_count++;
ext4_kvfree_array_rcu(o_group_desc);
return err;
}
/*
* 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)
{
struct super_block *sb = inode->i_sb;
int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
struct buffer_head **primary;
struct buffer_head *dind;
struct ext4_iloc iloc;
ext4_fsblk_t blk;
__le32 *data, *end;
int gdbackups = 0;
int res, i;
int err;
primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
if (!primary)
return -ENOMEM;
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
if (IS_ERR(dind)) {
err = PTR_ERR(dind);
dind = NULL;
goto exit_free;
}