/**
* nilfs_palloc_desc_blkoff - get block offset of a group descriptor block
* @inode: inode of metadata file using this allocator
* @group: group number
*
* nilfs_palloc_desc_blkoff() returns block offset of the descriptor
* block which contains a descriptor of the specified group.
*/
static unsigned long
nilfs_palloc_desc_blkoff(const struct inode *inode, unsigned long group)
{
unsigned long desc_block =
group / nilfs_palloc_groups_per_desc_block(inode);
return desc_block * NILFS_MDT(inode)->mi_blocks_per_desc_block;
}
/**
* nilfs_palloc_init_blockgroup - initialize private variables for allocator
* @inode: inode of metadata file using this allocator
* @entry_size: size of the persistent object
*/
int nilfs_palloc_init_blockgroup(struct inode *inode, unsigned int entry_size)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
mi->mi_bgl = kmalloc(sizeof(*mi->mi_bgl), GFP_NOFS);
if (!mi->mi_bgl)
return -ENOMEM;
bgl_lock_init(mi->mi_bgl);
nilfs_mdt_set_entry_size(inode, entry_size, 0);
mi->mi_blocks_per_group =
DIV_ROUND_UP(nilfs_palloc_entries_per_group(inode),
mi->mi_entries_per_block) + 1;
/*
* Number of blocks in a group including entry blocks
* and a bitmap block
*/
mi->mi_blocks_per_desc_block =
nilfs_palloc_groups_per_desc_block(inode) *
mi->mi_blocks_per_group + 1;
/*
* Number of blocks per descriptor including the
* descriptor block
*/
return 0;
}
/**
* nilfs_palloc_block_get_group_desc - get kernel address of a group descriptor
* @inode: inode of metadata file using this allocator
* @group: group number
* @bh: buffer head of the buffer storing the group descriptor block
* @kaddr: kernel address mapped for the page including the buffer
*/
static struct nilfs_palloc_group_desc *
nilfs_palloc_block_get_group_desc(const struct inode *inode,
unsigned long group,
const struct buffer_head *bh, void *kaddr)
{
return (struct nilfs_palloc_group_desc *)(kaddr + bh_offset(bh)) +
group % nilfs_palloc_groups_per_desc_block(inode);
}
/**
* nilfs_palloc_bitmap_blkoff - get block offset of a bitmap block
* @inode: inode of metadata file using this allocator
* @group: group number
*
* nilfs_palloc_bitmap_blkoff() returns block offset of the bitmap
* block used to allocate/deallocate entries in the specified group.
*/
static unsigned long
nilfs_palloc_bitmap_blkoff(const struct inode *inode, unsigned long group)
{
unsigned long desc_offset =
group % nilfs_palloc_groups_per_desc_block(inode);
return nilfs_palloc_desc_blkoff(inode, group) + 1 +
desc_offset * NILFS_MDT(inode)->mi_blocks_per_group;
}
/**
* nilfs_palloc_rest_groups_in_desc_block - get the remaining number of groups
* in a group descriptor block
* @inode: inode of metadata file using this allocator
* @curr: current group number
* @max: maximum number of groups
*/
static unsigned long
nilfs_palloc_rest_groups_in_desc_block(const struct inode *inode,
unsigned long curr, unsigned long max)
{
return min_t(unsigned long,
nilfs_palloc_groups_per_desc_block(inode) -
curr % nilfs_palloc_groups_per_desc_block(inode),
max - curr + 1);
}
/**
* nilfs_palloc_desc_block_init - initialize buffer of a group descriptor block
* @inode: inode of metadata file
* @bh: buffer head of the buffer to be initialized
* @kaddr: kernel address mapped for the page including the buffer
*/
static void nilfs_palloc_desc_block_init(struct inode *inode,
struct buffer_head *bh, void *kaddr)
{
struct nilfs_palloc_group_desc *desc = kaddr + bh_offset(bh);
unsigned long n = nilfs_palloc_groups_per_desc_block(inode);
__le32 nfrees;
nfrees = cpu_to_le32(nilfs_palloc_entries_per_group(inode));
while (n-- > 0) {
desc->pg_nfrees = nfrees;
desc++;
}
}
/**
* nilfs_palloc_count_max_entries - count max number of entries that can be
* described by descriptor blocks count
* @inode: inode of metadata file using this allocator
* @nused: current number of used entries
* @nmaxp: max number of entries [out]
*/
int nilfs_palloc_count_max_entries(struct inode *inode, u64 nused, u64 *nmaxp)
{
unsigned long desc_blocks = 0;
u64 entries_per_desc_block, nmax;
int err;
err = nilfs_palloc_count_desc_blocks(inode, &desc_blocks);
if (unlikely(err))
return err;
entries_per_desc_block = (u64)nilfs_palloc_entries_per_group(inode) *
nilfs_palloc_groups_per_desc_block(inode);
nmax = entries_per_desc_block * desc_blocks;
if (nused == nmax &&
nilfs_palloc_mdt_file_can_grow(inode, desc_blocks))
nmax += entries_per_desc_block;
if (nused > nmax)
return -ERANGE;
*nmaxp = nmax;
return 0;
}
/**
* nilfs_palloc_mdt_file_can_grow - check potential opportunity for
* MDT file growing
* @inode: inode of metadata file using this allocator
* @desc_blocks: known current descriptor blocks count
*/
static inline bool nilfs_palloc_mdt_file_can_grow(struct inode *inode,
unsigned long desc_blocks)
{
return (nilfs_palloc_groups_per_desc_block(inode) * desc_blocks) <
nilfs_palloc_groups_count(inode);
}
/**
* nilfs_palloc_prepare_alloc_entry - prepare to allocate a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the allocation
*/
int nilfs_palloc_prepare_alloc_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
struct buffer_head *desc_bh, *bitmap_bh;
struct nilfs_palloc_group_desc *desc;
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
unsigned long group, maxgroup, ngroups;
unsigned long group_offset, maxgroup_offset;
unsigned long n, entries_per_group, groups_per_desc_block;
unsigned long i, j;
int pos, ret;
ngroups = nilfs_palloc_groups_count(inode);
maxgroup = ngroups - 1;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
entries_per_group = nilfs_palloc_entries_per_group(inode);
groups_per_desc_block = nilfs_palloc_groups_per_desc_block(inode);
for (i = 0; i < ngroups; i += n) {
if (group >= ngroups) {
/* wrap around */
group = 0;
maxgroup = nilfs_palloc_group(inode, req->pr_entry_nr,
&maxgroup_offset) - 1;
}
ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
if (ret < 0)
return ret;
desc_kaddr = kmap(desc_bh->b_page);
desc = nilfs_palloc_block_get_group_desc(
inode, group, desc_bh, desc_kaddr);
n = nilfs_palloc_rest_groups_in_desc_block(inode, group,
maxgroup);
for (j = 0; j < n; j++, desc++, group++) {
if (nilfs_palloc_group_desc_nfrees(inode, group, desc)
> 0) {
ret = nilfs_palloc_get_bitmap_block(
inode, group, 1, &bitmap_bh);
if (ret < 0)
goto out_desc;
bitmap_kaddr = kmap(bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
pos = nilfs_palloc_find_available_slot(
inode, group, group_offset, bitmap,
entries_per_group);
if (pos >= 0) {
/* found a free entry */
nilfs_palloc_group_desc_add_entries(
inode, group, desc, -1);
req->pr_entry_nr =
entries_per_group * group + pos;
kunmap(desc_bh->b_page);
kunmap(bitmap_bh->b_page);
req->pr_desc_bh = desc_bh;
req->pr_bitmap_bh = bitmap_bh;
return 0;
}
kunmap(bitmap_bh->b_page);
brelse(bitmap_bh);
}
group_offset = 0;
}
kunmap(desc_bh->b_page);
brelse(desc_bh);
}
/* no entries left */
return -ENOSPC;
out_desc:
kunmap(desc_bh->b_page);
brelse(desc_bh);
return ret;
}
