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linux/fs/ext4/resize.c
Jan Kara 2c869b262a ext4: fix growing of tiny filesystems 
The estimate of necessary transaction credits in ext4_flex_group_add()
is too pessimistic. It reserves credit for sb, resize inode, and resize
inode dindirect block for each group added in a flex group although they
are always the same block and thus it is enough to account them only
once. Also the number of modified GDT block is overestimated since we
fit EXT4_DESC_PER_BLOCK(sb) descriptors in one block.

Make the estimation more precise. That reduces number of requested
credits enough that we can grow 20 MB filesystem (which has 1 MB
journal, 79 reserved GDT blocks, and flex group size 16 by default).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2015-05-02 23:58:32 -04:00

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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;
/*
* 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;
}
/*
* 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);
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
* blocks. 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 = 3; /* sb, resize inode, resize inode dindirect */
/* GDT blocks */
credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
credit += reserved_gdb; /* Reserved GDT dindirect blocks */
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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