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ext4: fix online resize with mballoc
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Update group infos when updating a group's descriptor.
Add group infos when adding a group's descriptor.
Refresh cache pages used by mb_alloc when changes occur.
This will probably need modifications when META_BG resizing will be allowed.

Signed-off-by: Frederic Bohe <frederic.bohe@bull.net>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
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Frederic Bohe authored and Theodore Ts'o committed Jul 11, 2008
1 parent 953e622 commit 5f21b0e
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Showing 3 changed files with 234 additions and 56 deletions.
4 changes: 4 additions & 0 deletions fs/ext4/ext4.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1033,6 +1033,10 @@ extern int __init init_ext4_mballoc(void);
extern void exit_ext4_mballoc(void);
extern void ext4_mb_free_blocks(handle_t *, struct inode *,
unsigned long, unsigned long, int, unsigned long *);
extern int ext4_mb_add_more_groupinfo(struct super_block *sb,
ext4_group_t i, struct ext4_group_desc *desc);
extern void ext4_mb_update_group_info(struct ext4_group_info *grp,
ext4_grpblk_t add);


/* inode.c */
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234 changes: 179 additions & 55 deletions fs/ext4/mballoc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2236,21 +2236,192 @@ ext4_mb_store_history(struct ext4_allocation_context *ac)
#define ext4_mb_history_init(sb)
#endif


/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i, len;
int metalen = 0;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_info **meta_group_info;

/*
* First check if this group is the first of a reserved block.
* If it's true, we have to allocate a new table of pointers
* to ext4_group_info structures
*/
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
metalen = sizeof(*meta_group_info) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
meta_group_info = kmalloc(metalen, GFP_KERNEL);
if (meta_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
"buddy group\n");
goto exit_meta_group_info;
}
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
meta_group_info;
}

/*
* calculate needed size. if change bb_counters size,
* don't forget about ext4_mb_generate_buddy()
*/
len = offsetof(typeof(**meta_group_info),
bb_counters[sb->s_blocksize_bits + 2]);

meta_group_info =
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);

meta_group_info[i] = kzalloc(len, GFP_KERNEL);
if (meta_group_info[i] == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
goto exit_group_info;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[i]->bb_state));

/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
meta_group_info[i]->bb_free =
ext4_free_blocks_after_init(sb, group, desc);
} else {
meta_group_info[i]->bb_free =
le16_to_cpu(desc->bg_free_blocks_count);
}

INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);

#ifdef DOUBLE_CHECK
{
struct buffer_head *bh;
meta_group_info[i]->bb_bitmap =
kmalloc(sb->s_blocksize, GFP_KERNEL);
BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
bh = ext4_read_block_bitmap(sb, group);
BUG_ON(bh == NULL);
memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
sb->s_blocksize);
put_bh(bh);
}
#endif

return 0;

exit_group_info:
/* If a meta_group_info table has been allocated, release it now */
if (group % EXT4_DESC_PER_BLOCK(sb) == 0)
kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
exit_meta_group_info:
return -ENOMEM;
} /* ext4_mb_add_groupinfo */

/*
* Add a group to the existing groups.
* This function is used for online resize
*/
int ext4_mb_add_more_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
int blocks_per_page;
int block;
int pnum;
struct page *page;
int err;

/* Add group based on group descriptor*/
err = ext4_mb_add_groupinfo(sb, group, desc);
if (err)
return err;

/*
* Cache pages containing dynamic mb_alloc datas (buddy and bitmap
* datas) are set not up to date so that they will be re-initilaized
* during the next call to ext4_mb_load_buddy
*/

/* Set buddy page as not up to date */
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
block = group * 2;
pnum = block / blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page != NULL) {
ClearPageUptodate(page);
page_cache_release(page);
}

/* Set bitmap page as not up to date */
block++;
pnum = block / blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page != NULL) {
ClearPageUptodate(page);
page_cache_release(page);
}

return 0;
}

/*
* Update an existing group.
* This function is used for online resize
*/
void ext4_mb_update_group_info(struct ext4_group_info *grp, ext4_grpblk_t add)
{
grp->bb_free += add;
}

static int ext4_mb_init_backend(struct super_block *sb)
{
ext4_group_t i;
int j, len, metalen;
int metalen;
struct ext4_sb_info *sbi = EXT4_SB(sb);
int num_meta_group_infos =
(sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
struct ext4_super_block *es = sbi->s_es;
int num_meta_group_infos;
int num_meta_group_infos_max;
int array_size;
struct ext4_group_info **meta_group_info;
struct ext4_group_desc *desc;

/* This is the number of blocks used by GDT */
num_meta_group_infos = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) -
1) >> EXT4_DESC_PER_BLOCK_BITS(sb);

/*
* This is the total number of blocks used by GDT including
* the number of reserved blocks for GDT.
* The s_group_info array is allocated with this value
* to allow a clean online resize without a complex
* manipulation of pointer.
* The drawback is the unused memory when no resize
* occurs but it's very low in terms of pages
* (see comments below)
* Need to handle this properly when META_BG resizing is allowed
*/
num_meta_group_infos_max = num_meta_group_infos +
le16_to_cpu(es->s_reserved_gdt_blocks);

/*
* array_size is the size of s_group_info array. We round it
* to the next power of two because this approximation is done
* internally by kmalloc so we can have some more memory
* for free here (e.g. may be used for META_BG resize).
*/
array_size = 1;
while (array_size < sizeof(*sbi->s_group_info) *
num_meta_group_infos_max)
array_size = array_size << 1;
/* An 8TB filesystem with 64-bit pointers requires a 4096 byte
* kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
* So a two level scheme suffices for now. */
sbi->s_group_info = kmalloc(sizeof(*sbi->s_group_info) *
num_meta_group_infos, GFP_KERNEL);
sbi->s_group_info = kmalloc(array_size, GFP_KERNEL);
if (sbi->s_group_info == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n");
return -ENOMEM;
Expand All @@ -2277,62 +2448,15 @@ static int ext4_mb_init_backend(struct super_block *sb)
sbi->s_group_info[i] = meta_group_info;
}

/*
* calculate needed size. if change bb_counters size,
* don't forget about ext4_mb_generate_buddy()
*/
len = sizeof(struct ext4_group_info);
len += sizeof(unsigned short) * (sb->s_blocksize_bits + 2);
for (i = 0; i < sbi->s_groups_count; i++) {
struct ext4_group_desc *desc;

meta_group_info =
sbi->s_group_info[i >> EXT4_DESC_PER_BLOCK_BITS(sb)];
j = i & (EXT4_DESC_PER_BLOCK(sb) - 1);

meta_group_info[j] = kzalloc(len, GFP_KERNEL);
if (meta_group_info[j] == NULL) {
printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
goto err_freebuddy;
}
desc = ext4_get_group_desc(sb, i, NULL);
if (desc == NULL) {
printk(KERN_ERR
"EXT4-fs: can't read descriptor %lu\n", i);
i++;
goto err_freebuddy;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[j]->bb_state));

/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
meta_group_info[j]->bb_free =
ext4_free_blocks_after_init(sb, i, desc);
} else {
meta_group_info[j]->bb_free =
le16_to_cpu(desc->bg_free_blocks_count);
}

INIT_LIST_HEAD(&meta_group_info[j]->bb_prealloc_list);

#ifdef DOUBLE_CHECK
{
struct buffer_head *bh;
meta_group_info[j]->bb_bitmap =
kmalloc(sb->s_blocksize, GFP_KERNEL);
BUG_ON(meta_group_info[j]->bb_bitmap == NULL);
bh = ext4_read_block_bitmap(sb, i);
BUG_ON(bh == NULL);
memcpy(meta_group_info[j]->bb_bitmap, bh->b_data,
sb->s_blocksize);
put_bh(bh);
}
#endif

if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
goto err_freebuddy;
}

return 0;
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52 changes: 51 additions & 1 deletion fs/ext4/resize.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -865,6 +865,15 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb));
gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);

/*
* We can allocate memory for mb_alloc based on the new group
* descriptor
*/
if (test_opt(sb, MBALLOC)) {
err = ext4_mb_add_more_groupinfo(sb, input->group, gdp);
if (err)
goto exit_journal;
}
/*
* Make the new blocks and inodes valid next. We do this before
* increasing the group count so that once the group is enabled,
Expand Down Expand Up @@ -957,6 +966,8 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
handle_t *handle;
int err;
unsigned long freed_blocks;
ext4_group_t group;
struct ext4_group_info *grp;

/* We don't need to worry about locking wrt other resizers just
* yet: we're going to revalidate es->s_blocks_count after
Expand Down Expand Up @@ -988,7 +999,7 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
}

/* Handle the remaining blocks in the last group only. */
ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last);
ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);

if (last == 0) {
ext4_warning(sb, __func__,
Expand Down Expand Up @@ -1060,6 +1071,45 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
o_blocks_count + add);
if ((err = ext4_journal_stop(handle)))
goto exit_put;

/*
* Mark mballoc pages as not up to date so that they will be updated
* next time they are loaded by ext4_mb_load_buddy.
*/
if (test_opt(sb, MBALLOC)) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
int blocks_per_page;
int block;
int pnum;
struct page *page;

/* Set buddy page as not up to date */
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
block = group * 2;
pnum = block / blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page != NULL) {
ClearPageUptodate(page);
page_cache_release(page);
}

/* Set bitmap page as not up to date */
block++;
pnum = block / blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
if (page != NULL) {
ClearPageUptodate(page);
page_cache_release(page);
}

/* Get the info on the last group */
grp = ext4_get_group_info(sb, group);

/* Update free blocks in group info */
ext4_mb_update_group_info(grp, add);
}

if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
ext4_blocks_count(es));
Expand Down

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