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linux/fs/ext4/resize.c

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/*
* linux/fs/ext4/resize.c
*
* Support for resizing an ext4 filesystem while it is mounted.
*
* Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
*
* 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"
int ext4_resize_begin(struct super_block *sb)
{
int ret = 0;
if (!capable(CAP_SYS_RESOURCE))
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\n");
return -EPERM;
}
if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
ret = -EBUSY;
return ret;
}
void ext4_resize_end(struct super_block *sb)
{
clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_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_blocks_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 (!(bh = sb_bread(sb, end - 1)))
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_flex_group_data))
goto out2;
flex_gd->count = flexbg_size;
flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
flexbg_size, GFP_NOFS);
if (flex_gd->groups == NULL)
goto out2;
flex_gd->bg_flags = kmalloc(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;
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].free_blocks_count--;
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].free_blocks_count--;
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].free_blocks_count -= overhead;
itb -= overhead;
}
group_data[group].free_blocks_count -= itb;
flex_gd->bg_flags[group] &= uninit_mask;
start_blk += EXT4_SB(sb)->s_itb_per_group;
}
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++) {
printk(KERN_DEBUG "adding %s group %u: %u "
"blocks (%d free)\n",
ext4_bg_has_super(sb, group + i) ? "normal" :
"no-super", group + i,
group_data[i].blocks_count,
group_data[i].free_blocks_count);
}
}
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;
}
/*
* If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
* If that fails, restart the transaction & regain write access for the
* buffer head which is used for block_bitmap modifications.
*/
static int extend_or_restart_transaction(handle_t *handle, int thresh)
{
int err;
if (ext4_handle_has_enough_credits(handle, thresh))
return 0;
err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
if (err < 0)
return err;
if (err) {
err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
if (err)
return err;
}
return 0;
}
/*
* set_flexbg_block_bitmap() mark @count blocks starting from @block 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 block, ext4_group_t count)
{
ext4_group_t count2;
ext4_debug("mark blocks [%llu/%u] used\n", block, count);
for (count2 = count; count > 0; count -= count2, block += count2) {
ext4_fsblk_t start;
struct buffer_head *bh;
ext4_group_t group;
int err;
group = ext4_get_group_number(sb, block);
start = ext4_group_first_block_no(sb, group);
group -= flex_gd->groups[0].group;
count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
if (count2 > count)
count2 = count;
if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
BUG_ON(flex_gd->count > 1);
continue;
}
err = extend_or_restart_transaction(handle, 1);
if (err)
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)
return err;
ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
block - start, count2);
ext4_set_bits(bh->b_data, block - start, count2);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (unlikely(err))
return err;
brelse(bh);
}
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_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
/* 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 = extend_or_restart_transaction(handle, 1);
if (err)
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->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 = extend_or_restart_transaction(handle, 1);
if (err)
goto out;
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
bh = NULL;
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, overhead);
}
ext4_mark_bitmap_end(group_data[i].blocks_count,
sb->s_blocksize * 8, bh->b_data);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (err)
goto out;
brelse(bh);
handle_ib:
if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
continue;
/* Initialize inode bitmap of the @group */
block = group_data[i].inode_bitmap;
err = extend_or_restart_transaction(handle, 1);
if (err)
goto out;
/* Mark unused entries in inode bitmap used */
bh = bclean(handle, sb, block);
if (IS_ERR(bh)) {
err = PTR_ERR(bh);
bh = NULL;
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);
if (err)
goto out;
brelse(bh);
}
bh = NULL;
/* 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, start, count);
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, start, count);
if (err)
goto out;
}
}
out:
brelse(bh);
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_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
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;
struct buffer_head *dind;
struct buffer_head *gdb_bh;
int gdbackups;
struct ext4_iloc iloc;
__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);
/*
* 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_SB(sb)->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;
}
gdb_bh = sb_bread(sb, gdblock);
if (!gdb_bh)
return -EIO;
gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
if (gdbackups < 0) {
err = gdbackups;
goto exit_bh;
}
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
dind = sb_bread(sb, le32_to_cpu(*data));
if (!dind) {
err = -EIO;
goto exit_bh;
}
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 exit_dind;
}
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 exit_dind;
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (unlikely(err))
goto exit_dind;
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 exit_dind;
n_group_desc = ext4_kvmalloc((gdb_num + 1) *
sizeof(struct buffer_head *),
GFP_NOFS);
if (!n_group_desc) {
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
goto exit_inode;
}
/*
* 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 exit_inode;
}
inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
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);
goto exit_inode;
}
brelse(dind);
o_group_desc = EXT4_SB(sb)->s_group_desc;
memcpy(n_group_desc, o_group_desc,
EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
n_group_desc[gdb_num] = gdb_bh;
EXT4_SB(sb)->s_group_desc = n_group_desc;
EXT4_SB(sb)->s_gdb_count++;
kvfree(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;
exit_inode:
kvfree(n_group_desc);
brelse(iloc.bh);
exit_dind:
brelse(dind);
exit_bh:
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 = sb_bread(sb, gdblock);
if (!gdb_bh)
return -EIO;
n_group_desc = ext4_kvmalloc((gdb_num + 1) *
sizeof(struct buffer_head *),
GFP_NOFS);
if (!n_group_desc) {
err = -ENOMEM;
ext4_warning(sb, "not enough memory for %lu groups",
gdb_num + 1);
return err;
}
o_group_desc = EXT4_SB(sb)->s_group_desc;
memcpy(n_group_desc, o_group_desc,
EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
n_group_desc[gdb_num] = gdb_bh;
EXT4_SB(sb)->s_group_desc = n_group_desc;
EXT4_SB(sb)->s_gdb_count++;
kvfree(o_group_desc);
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (unlikely(err))
brelse(gdb_bh);
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);
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(reserved_gdb * sizeof(*primary), GFP_NOFS);
if (!primary)
return -ENOMEM;
data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
dind = sb_bread(sb, le32_to_cpu(*data));
if (!dind) {
err = -EIO;
goto exit_free;
}
blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
EXT4_ADDR_PER_BLOCK(sb));
end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
/* Get each reserved primary GDT block and verify it holds backups */
for (res = 0; res < reserved_gdb; res++, blk++) {
if (le32_to_cpu(*data) != blk) {
ext4_warning(sb, "reserved block %llu"
" not at offset %ld",
blk,
(long)(data - (__le32 *)dind->b_data));
err = -EINVAL;
goto exit_bh;
}
primary[res] = sb_bread(sb, blk);
if (!primary[res]) {
err = -EIO;
goto exit_bh;
}
gdbackups = verify_reserved_gdb(sb, group, primary[res]);
if (gdbackups < 0) {
brelse(primary[res]);
err = gdbackups;
goto exit_bh;
}
if (++data >= end)
data = (__le32 *)dind->b_data;
}
for (i = 0; i < reserved_gdb; i++) {
BUFFER_TRACE(primary[i], "get_write_access");
if ((err = ext4_journal_get_write_access(handle, primary[i])))
goto exit_bh;
}
if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
goto exit_bh;
/*
* Finally we can add each of the reserved backup GDT blocks from
* the new group to its reserved primary GDT block.
*/
blk = group * EXT4_BLOCKS_PER_GROUP(sb);
for (i = 0; i < reserved_gdb; i++) {
int err2;
data = (__le32 *)primary[i]->b_data;
/* printk("reserving backup %lu[%u] = %lu\n",
primary[i]->b_blocknr, gdbackups,
blk + primary[i]->b_blocknr); */
data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
if (!err)
err = err2;
}
inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
ext4_mark_iloc_dirty(handle, inode, &iloc);
exit_bh:
while (--res >= 0)
brelse(primary[res]);
brelse(dind);
exit_free:
kfree(primary);
return err;
}
/*
* 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, int blk_off, char *data,
int size, int meta_bg)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t last;
const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
unsigned three = 1;
unsigned five = 5;
unsigned seven = 7;
ext4_group_t group = 0;
int rest = sb->s_blocksize - size;
handle_t *handle;
int err = 0, err2;
handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
if (IS_ERR(handle)) {
group = 1;
err = PTR_ERR(handle);
goto exit_err;
}
if (meta_bg == 0) {
group = ext4_list_backups(sb, &three, &five, &seven);
last = sbi->s_groups_count;
} else {
group = ext4_meta_bg_first_group(sb, group) + 1;
last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
}
while (group < sbi->s_groups_count) {
struct buffer_head *bh;
ext4_fsblk_t backup_block;
/* Out of journal space, and can't get more - abort - so sad */
if (ext4_handle_valid(handle) &&
handle->h_buffer_credits == 0 &&
ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
(err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
break;
if (meta_bg == 0)
backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
else
backup_block = (ext4_group_first_block_no(sb, group) +
ext4_bg_has_super(sb, group));
bh = sb_getblk(sb, backup_block);
if (unlikely(!bh)) {
err = -ENOMEM;
break;
}
ext4_debug("update metadata backup %llu(+%llu)\n",
backup_block, backup_block -
ext4_group_first_block_no(sb, group));
BUFFER_TRACE(bh, "get_write_access");
if ((err = ext4_journal_get_write_access(handle, bh)))
break;
lock_buffer(bh);
memcpy(bh->b_data, data, size);
if (rest)
memset(bh->b_data + size, 0, rest);
set_buffer_uptodate(bh);
unlock_buffer(bh);
err = ext4_handle_dirty_metadata(handle, NULL, bh);
if (unlikely(err))
ext4_std_error(sb, err);
brelse(bh);
if (meta_bg == 0)
group = ext4_list_backups(sb, &three, &five, &seven);
else if (group == last)
break;
else
group = last;
}
if ((err2 = ext4_journal_stop(handle)) && !err)
err = err2;
/*
* Ugh! Need to have e2fsck write the backup copies. It is too
* late to revert the resize, we shouldn't fail just because of
* the backup copies (they are only needed in case of corruption).
*
* However, if we got here we have a journal problem too, so we
* can't really start a transaction to mark the superblock.
* Chicken out and just set the flag on the hope it will be written
* to disk, and if not - we will simply wait until next fsck.
*/
exit_err:
if (err) {
ext4_warning(sb, "can't update backup for group %u (err %d), "
"forcing fsck on next reboot", group, err);
sbi->s_mount_state &= ~EXT4_VALID_FS;
sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
mark_buffer_dirty(sbi->s_sbh);
}
}
/*
* 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)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
struct buffer_head *gdb_bh;
int i, gdb_off, gdb_num, err = 0;
int meta_bg;
meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
for (i = 0; i < count; i++, group++) {
int reserved_gdb = ext4_bg_has_super(sb, group) ?
le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
/*
* We will only either add reserved group blocks to a backup group
* or remove reserved blocks for the first group in a new group block.
* Doing both would be mean more complex code, and sane people don't
* use non-sparse filesystems anymore. This is already checked above.
*/
if (gdb_off) {
gdb_bh = sbi->s_group_desc[gdb_num];
BUFFER_TRACE(gdb_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, gdb_bh);
if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
err = reserve_backup_gdb(handle, resize_inode, group);
} else if (meta_bg != 0) {
err = add_new_gdb_meta_bg(sb, handle, group);
} else {
err = add_new_gdb(handle, resize_inode, group);
}
if (err)
break;
}
return err;
}
static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
{
struct buffer_head *bh = sb_getblk(sb, block);
if (unlikely(!bh))
return NULL;
if (!bh_uptodate_or_lock(bh)) {
if (bh_submit_read(bh) < 0) {
brelse(bh);
return NULL;
}
}
return bh;
}
static int ext4_set_bitmap_checksums(struct super_block *sb,
ext4_group_t group,
struct ext4_group_desc *gdp,
struct ext4_new_group_data *group_data)
{
struct buffer_head *bh;
if (!ext4_has_metadata_csum(sb))
return 0;
bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
if (!bh)
return -EIO;
ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
EXT4_INODES_PER_GROUP(sb) / 8);
brelse(bh);
bh = ext4_get_bitmap(sb, group_data->block_bitmap);
if (!bh)
return -EIO;
ext4_block_bitmap_csum_set(sb, group, gdp, bh);
brelse(bh);
return 0;
}
/*
* 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)
{
struct ext4_new_group_data *group_data = flex_gd->groups;
struct ext4_group_desc *gdp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct buffer_head *gdb_bh;
ext4_group_t group;
__u16 *bg_flags = flex_gd->bg_flags;
int i, gdb_off, gdb_num, err = 0;
for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
group = group_data->group;
gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
/*
* get_write_access() has been called on gdb_bh by ext4_add_new_desc().
*/
gdb_bh = sbi->s_group_desc[gdb_num];
/* Update group descriptor block for new group */
gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
gdb_off * EXT4_DESC_SIZE(sb));
memset(gdp, 0, EXT4_DESC_SIZE(sb));
ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
if (err) {
ext4_std_error(sb, err);
break;
}
ext4_inode_table_set(sb, gdp, group_data->inode_table);
ext4_free_group_clusters_set(sb, gdp,
EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
if (ext4_has_group_desc_csum(sb))
ext4_itable_unused_set(sb, gdp,
EXT4_INODES_PER_GROUP(sb));
gdp->bg_flags = cpu_to_le16(*bg_flags);
ext4_group_desc_csum_set(sb, group, gdp);
err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
if (unlikely(err)) {
ext4_std_error(sb, err);
break;
}
/*
* We can allocate memory for mb_alloc based on the new group
* descriptor
*/
err = ext4_mb_add_groupinfo(sb, group, gdp);
if (err)
break;
}
return err;
}
/*
* 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)
{
ext4_fsblk_t blocks_count = 0;
ext4_fsblk_t free_blocks = 0;
ext4_fsblk_t reserved_blocks = 0;
struct ext4_new_group_data *group_data = flex_gd->groups;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
int i;
BUG_ON(flex_gd->count == 0 || group_data == NULL);
/*
* Make the new blocks and inodes valid next. We do this before
* increasing the group count so that once the group is enabled,
* all of its blocks and inodes are already valid.
*
* We always allocate group-by-group, then block-by-block or
* inode-by-inode within a group, so enabling these
* blocks/inodes before the group is live won't actually let us
* allocate the new space yet.
*/
for (i = 0; i < flex_gd->count; i++) {
blocks_count += group_data[i].blocks_count;
free_blocks += group_data[i].free_blocks_count;
}
reserved_blocks = ext4_r_blocks_count(es) * 100;
reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
reserved_blocks *= blocks_count;
do_div(reserved_blocks, 100);
ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
flex_gd->count);
le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
flex_gd->count);
ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
/*
* We need to protect s_groups_count against other CPUs seeing
* inconsistent state in the superblock.
*
* The precise rules we use are:
*
* * Writers must perform a smp_wmb() after updating all
* dependent data and before modifying the groups count
*
* * Readers must perform an smp_rmb() after reading the groups
* count and before reading any dependent data.
*
* NB. These rules can be relaxed when checking the group count
* while freeing data, as we can only allocate from a block
* group after serialising against the group count, and we can
* only then free after serialising in turn against that
* allocation.
*/
smp_wmb();
/* Update the global fs size fields */
sbi->s_groups_count += flex_gd->count;
sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
/* Update the reserved block counts only once the new group is
* active. */
ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
reserved_blocks);
/* Update the free space counts */
percpu_counter_add(&sbi->s_freeclusters_counter,
EXT4_NUM_B2C(sbi, free_blocks));
percpu_counter_add(&sbi->s_freeinodes_counter,
EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
ext4_debug("free blocks count %llu",
percpu_counter_read(&sbi->s_freeclusters_counter));
if (EXT4_HAS_INCOMPAT_FEATURE(sb,
EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
sbi->s_log_groups_per_flex) {
ext4_group_t flex_group;
flex_group = ext4_flex_group(sbi, group_data[0].group);
atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
&sbi->s_flex_groups[flex_group].free_clusters);
atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
&sbi->s_flex_groups[flex_group].free_inodes);
}
/*
* Update the fs overhead information
*/
ext4_calculate_overhead(sb);
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: added group %u:"
"%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
blocks_count, free_blocks, reserved_blocks);
}
/* 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)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_fsblk_t o_blocks_count;
ext4_grpblk_t last;
ext4_group_t group;
handle_t *handle;
unsigned reserved_gdb;
int err = 0, err2 = 0, credit;
BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
o_blocks_count = ext4_blocks_count(es);
ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
BUG_ON(last);
err = setup_new_flex_group_blocks(sb, flex_gd);
if (err)
goto exit;
/*
* We will always be modifying at least the superblock and GDT
* block. If we are adding a group past the last current GDT block,
* we will also modify the inode and the dindirect block. If we
* are adding a group with superblock/GDT backups we will also
* modify each of the reserved GDT dindirect blocks.
*/
credit = flex_gd->count * 4 + reserved_gdb;
handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
if (IS_ERR(handle)) {
err = PTR_ERR(handle);
goto exit;
}
BUFFER_TRACE(sbi->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, sbi->s_sbh);
if (err)
goto exit_journal;
group = flex_gd->groups[0].group;
BUG_ON(group != EXT4_SB(sb)->s_groups_count);
err = ext4_add_new_descs(handle, sb, group,
resize_inode, flex_gd->count);
if (err)
goto exit_journal;
err = ext4_setup_new_descs(handle, sb, flex_gd);
if (err)
goto exit_journal;
ext4_update_super(sb, flex_gd);
err = ext4_handle_dirty_super(handle, sb);
exit_journal:
err2 = ext4_journal_stop(handle);
if (!err)
err = err2;
if (!err) {
int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
int gdb_num_end = ((group + flex_gd->count - 1) /
EXT4_DESC_PER_BLOCK(sb));
int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,
EXT4_FEATURE_INCOMPAT_META_BG);
sector_t old_gdb = 0;
update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
sizeof(struct ext4_super_block), 0);
for (; gdb_num <= gdb_num_end; gdb_num++) {
struct buffer_head *gdb_bh;
gdb_bh = sbi->s_group_desc[gdb_num];
if (old_gdb == gdb_bh->b_blocknr)
continue;
update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
gdb_bh->b_size, meta_bg);
old_gdb = gdb_bh->b_blocknr;
}
}
exit:
return err;
}
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,
unsigned long flexbg_size)
{
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
struct ext4_new_group_data *group_data = flex_gd->groups;
ext4_fsblk_t o_blocks_count;
ext4_group_t n_group;
ext4_group_t group;
ext4_group_t last_group;
ext4_grpblk_t last;
ext4_grpblk_t blocks_per_group;
unsigned long i;
blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
o_blocks_count = ext4_blocks_count(es);
if (o_blocks_count == n_blocks_count)
return 0;
ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
BUG_ON(last);
ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
last_group = group | (flexbg_size - 1);
if (last_group > n_group)
last_group = n_group;
flex_gd->count = last_group - group + 1;
for (i = 0; i < flex_gd->count; i++) {
int overhead;
group_data[i].group = group + i;
group_data[i].blocks_count = blocks_per_group;
overhead = ext4_group_overhead_blocks(sb, group + i);
group_data[i].free_blocks_count = blocks_per_group - overhead;
if (ext4_has_group_desc_csum(sb)) {
flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
EXT4_BG_INODE_UNINIT;
if (!test_opt(sb, INIT_INODE_TABLE))
flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
} else
flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
}
if (last_group == n_group && ext4_has_group_desc_csum(sb))
/* We need to initialize block bitmap of last group. */
flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
if ((last_group == n_group) && (last != blocks_per_group - 1)) {
group_data[i - 1].blocks_count = last + 1;
group_data[i - 1].free_blocks_count -= blocks_per_group-
last - 1;
}
return 1;
}
/* 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)
{
struct ext4_new_flex_group_data flex_gd;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
struct inode *inode = NULL;
int gdb_off;
int err;
__u16 bg_flags = 0;
gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
ext4_warning(sb, "Can't resize non-sparse filesystem further");
return -EPERM;
}
if (ext4_blocks_count(es) + input->blocks_count <
ext4_blocks_count(es)) {
ext4_warning(sb, "blocks_count overflow");
return -EINVAL;
}
if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
le32_to_cpu(es->s_inodes_count)) {
ext4_warning(sb, "inodes_count overflow");
return -EINVAL;
}
if (reserved_gdb || gdb_off == 0) {
if (!EXT4_HAS_COMPAT_FEATURE(sb,
EXT4_FEATURE_COMPAT_RESIZE_INODE)
|| !le16_to_cpu(es->s_reserved_gdt_blocks)) {
ext4_warning(sb,
"No reserved GDT blocks, can't resize");
return -EPERM;
}
inode = ext4_iget(sb, EXT4_RESIZE_INO);
if (IS_ERR(inode)) {
ext4_warning(sb, "Error opening resize inode");
return PTR_ERR(inode);
}
}
err = verify_group_input(sb, input);
if (err)
goto out;
err = ext4_alloc_flex_bg_array(sb, input->group + 1);
if (err)
goto out;
err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
if (err)
goto out;
flex_gd.count = 1;
flex_gd.groups = input;
flex_gd.bg_flags = &bg_flags;
err = ext4_flex_group_add(sb, inode, &flex_gd);
out:
iput(inode);
return err;
} /* 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)
{
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
handle_t *handle;
int err = 0, err2;
/* We will update the superblock, one block bitmap, and
* one group descriptor via ext4_group_add_blocks().
*/
handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
if (IS_ERR(handle)) {
err = PTR_ERR(handle);
ext4_warning(sb, "error %d on journal start", err);
return err;
}
BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
if (err) {
ext4_warning(sb, "error %d on journal write access", err);
goto errout;
}
ext4_blocks_count_set(es, o_blocks_count + add);
ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
o_blocks_count + add);
/* We add the blocks to the bitmap and set the group need init bit */
err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
if (err)
goto errout;
ext4_handle_dirty_super(handle, sb);
ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
o_blocks_count + add);
errout:
err2 = ext4_journal_stop(handle);
if (err2 && !err)
err = err2;
if (!err) {
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
"blocks\n", ext4_blocks_count(es));
update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
(char *)es, sizeof(struct ext4_super_block), 0);
}
return err;
}
/*
* 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_fsblk_t o_blocks_count;
ext4_grpblk_t last;
ext4_grpblk_t add;
struct buffer_head *bh;
int err;
ext4_group_t group;
o_blocks_count = ext4_blocks_count(es);
if (test_opt(sb, DEBUG))
ext4_msg(sb, KERN_DEBUG,
"extending last group from %llu to %llu blocks",
o_blocks_count, n_blocks_count);
if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
return 0;
if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
ext4_msg(sb, KERN_ERR,
"filesystem too large to resize to %llu blocks safely",
n_blocks_count);
if (sizeof(sector_t) < 8)
ext4_warning(sb, "CONFIG_LBDAF not enabled");
return -EINVAL;
}
if (n_blocks_count < o_blocks_count) {
ext4_warning(sb, "can't shrink FS - resize aborted");
return -EINVAL;
}
/* Handle the remaining blocks in the last group only. */
ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
if (last == 0) {
ext4_warning(sb, "need to use ext2online to resize further");
return -EPERM;
}
add = EXT4_BLOCKS_PER_GROUP(sb) - last;
if (o_blocks_count + add < o_blocks_count) {
ext4_warning(sb, "blocks_count overflow");
return -EINVAL;
}
if (o_blocks_count + add > n_blocks_count)
add = n_blocks_count - o_blocks_count;
if (o_blocks_count + add < n_blocks_count)
ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
o_blocks_count + add, add);
/* See if the device is actually as big as what was requested */
bh = sb_bread(sb, o_blocks_count + add - 1);
if (!bh) {
ext4_warning(sb, "can't read last block, resize aborted");
return -ENOSPC;
}
brelse(bh);
err = ext4_group_extend_no_check(sb, o_blocks_count, add);
return err;
} /* ext4_group_extend */
static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
{
return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
}
/*
* 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)
{
handle_t *handle;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
struct ext4_inode_info *ei = EXT4_I(inode);
ext4_fsblk_t nr;
int i, ret, err = 0;
int credits = 1;
ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
if (inode) {
if (es->s_reserved_gdt_blocks) {
ext4_error(sb, "Unexpected non-zero "
"s_reserved_gdt_blocks");
return -EPERM;
}
/* Do a quick sanity check of the resize inode */
if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
goto invalid_resize_inode;
for (i = 0; i < EXT4_N_BLOCKS; i++) {
if (i == EXT4_DIND_BLOCK) {
if (ei->i_data[i])
continue;
else
goto invalid_resize_inode;
}
if (ei->i_data[i])
goto invalid_resize_inode;
}
credits += 3; /* block bitmap, bg descriptor, resize inode */
}
handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
if (IS_ERR(handle))
return PTR_ERR(handle);
BUFFER_TRACE(sbi->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, sbi->s_sbh);
if (err)
goto errout;
EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
sbi->s_es->s_first_meta_bg =
cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
err = ext4_handle_dirty_super(handle, sb);
if (err) {
ext4_std_error(sb, err);
goto errout;
}
if (inode) {
nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
ext4_free_blocks(handle, inode, NULL, nr, 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
ei->i_data[EXT4_DIND_BLOCK] = 0;
inode->i_blocks = 0;
err = ext4_mark_inode_dirty(handle, inode);
if (err)
ext4_std_error(sb, err);
}
errout:
ret = ext4_journal_stop(handle);
if (!err)
err = ret;
return ret;
invalid_resize_inode:
ext4_error(sb, "corrupted/inconsistent resize inode");
return -EINVAL;
}
/*
* 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)
{
struct ext4_new_flex_group_data *flex_gd = NULL;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
struct buffer_head *bh;
struct inode *resize_inode = NULL;
ext4_grpblk_t add, offset;
unsigned long n_desc_blocks;
unsigned long o_desc_blocks;
ext4_group_t o_group;
ext4_group_t n_group;
ext4_fsblk_t o_blocks_count;
ext4_fsblk_t n_blocks_count_retry = 0;
unsigned long last_update_time = 0;
int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
int meta_bg;
/* See if the device is actually as big as what was requested */
bh = sb_bread(sb, n_blocks_count - 1);
if (!bh) {
ext4_warning(sb, "can't read last block, resize aborted");
return -ENOSPC;
}
brelse(bh);
retry:
o_blocks_count = ext4_blocks_count(es);
ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
"to %llu blocks", o_blocks_count, n_blocks_count);
if (n_blocks_count < o_blocks_count) {
/* On-line shrinking not supported */
ext4_warning(sb, "can't shrink FS - resize aborted");
return -EINVAL;
}
if (n_blocks_count == o_blocks_count)
/* Nothing need to do */
return 0;
n_group = ext4_get_group_number(sb, n_blocks_count - 1);
if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
ext4_warning(sb, "resize would cause inodes_count overflow");
return -EINVAL;
}
ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
n_desc_blocks = num_desc_blocks(sb, n_group + 1);
o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
if (meta_bg) {
ext4_error(sb, "resize_inode and meta_bg enabled "
"simultaneously");
return -EINVAL;
}
if (n_desc_blocks > o_desc_blocks +
le16_to_cpu(es->s_reserved_gdt_blocks)) {
n_blocks_count_retry = n_blocks_count;
n_desc_blocks = o_desc_blocks +
le16_to_cpu(es->s_reserved_gdt_blocks);
n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
n_group--; /* set to last group number */
}
if (!resize_inode)
resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
if (IS_ERR(resize_inode)) {
ext4_warning(sb, "Error opening resize inode");
return PTR_ERR(resize_inode);
}
}
if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
err = ext4_convert_meta_bg(sb, resize_inode);
if (err)
goto out;
if (resize_inode) {
iput(resize_inode);
resize_inode = NULL;
}
if (n_blocks_count_retry) {
n_blocks_count = n_blocks_count_retry;
n_blocks_count_retry = 0;
goto retry;
}
}
/* extend the last group */
if (n_group == o_group)
add = n_blocks_count - o_blocks_count;
else
add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
if (add > 0) {
err = ext4_group_extend_no_check(sb, o_blocks_count, add);
if (err)
goto out;
}
if (ext4_blocks_count(es) == n_blocks_count)
goto out;
err = ext4_alloc_flex_bg_array(sb, n_group + 1);
if (err)
return err;
err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
if (err)
goto out;
flex_gd = alloc_flex_gd(flexbg_size);
if (flex_gd == NULL) {
err = -ENOMEM;
goto out;
}
/* Add flex groups. Note that a regular group is a
* flex group with 1 group.
*/
while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
flexbg_size)) {
if (jiffies - last_update_time > HZ * 10) {
if (last_update_time)
ext4_msg(sb, KERN_INFO,
"resized to %llu blocks",
ext4_blocks_count(es));
last_update_time = jiffies;
}
if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
break;
err = ext4_flex_group_add(sb, resize_inode, flex_gd);
if (unlikely(err))
break;
}
if (!err && n_blocks_count_retry) {
n_blocks_count = n_blocks_count_retry;
n_blocks_count_retry = 0;
free_flex_gd(flex_gd);
flex_gd = NULL;
goto retry;
}
out:
if (flex_gd)
free_flex_gd(flex_gd);
if (resize_inode != NULL)
iput(resize_inode);
ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
return err;
}
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