- 根目录:
- fs
- nilfs2
- alloc.c
/*
* alloc.c - NILFS dat/inode allocator
*
* Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Original code was written by Koji Sato <koji@osrg.net>.
* Two allocators were unified by Ryusuke Konishi <ryusuke@osrg.net>,
* Amagai Yoshiji <amagai@osrg.net>.
*/
#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include "mdt.h"
#include "alloc.h"
/**
* nilfs_palloc_groups_per_desc_block - get the number of groups that a group
* descriptor block can maintain
* @inode: inode of metadata file using this allocator
*/
static inline unsigned long
nilfs_palloc_groups_per_desc_block(const struct inode *inode)
{
return (1UL << inode->i_blkbits) /
sizeof(struct nilfs_palloc_group_desc);
}
/**
* nilfs_palloc_groups_count - get maximum number of groups
* @inode: inode of metadata file using this allocator
*/
static inline unsigned long
nilfs_palloc_groups_count(const struct inode *inode)
{
return 1UL << (BITS_PER_LONG - (inode->i_blkbits + 3 /* log2(8) */));
}
/**
* 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 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_group - get group number and offset from an entry number
* @inode: inode of metadata file using this allocator
* @nr: serial number of the entry (e.g. inode number)
* @offset: pointer to store offset number in the group
*/
static unsigned long nilfs_palloc_group(const struct inode *inode, __u64 nr,
unsigned long *offset)
{
__u64 group = nr;
*offset = do_div(group, nilfs_palloc_entries_per_group(inode));
return group;
}
/**
* 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_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_group_desc_nfrees - get the number of free entries in a group
* @inode: inode of metadata file using this allocator
* @group: group number
* @desc: pointer to descriptor structure for the group
*/
static unsigned long
nilfs_palloc_group_desc_nfrees(struct inode *inode, unsigned long group,
const struct nilfs_palloc_group_desc *desc)
{
unsigned long nfree;
spin_lock(nilfs_mdt_bgl_lock(inode, group));
nfree = le32_to_cpu(desc->pg_nfrees);
spin_unlock(nilfs_mdt_bgl_lock(inode, group));
return nfree;
}
/**
* nilfs_palloc_group_desc_add_entries - adjust count of free entries
* @inode: inode of metadata file using this allocator
* @group: group number
* @desc: pointer to descriptor structure for the group
* @n: delta to be added
*/
static void
nilfs_palloc_group_desc_add_entries(struct inode *inode,
unsigned long group,
struct nilfs_palloc_group_desc *desc,
u32 n)
{
spin_lock(nilfs_mdt_bgl_lock(inode, group));
le32_add_cpu(&desc->pg_nfrees, n);
spin_unlock(nilfs_mdt_bgl_lock(inode, group));
}
/**
* nilfs_palloc_entry_blkoff - get block offset of an entry block
* @inode: inode of metadata file using this allocator
* @nr: serial number of the entry (e.g. inode number)
*/
static unsigned long
nilfs_palloc_entry_blkoff(const struct inode *inode, __u64 nr)
{
unsigned long group, group_offset;
group = nilfs_palloc_group(inode, nr, &group_offset);
return nilfs_palloc_bitmap_blkoff(inode, group) + 1 +
group_offset / NILFS_MDT(inode)->mi_entries_per_block;
}
/**
* 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++;
}
}
static int nilfs_palloc_get_block(struct inode *inode, unsigned long blkoff,
int create,
void (*init_block)(struct inode *,
struct buffer_head *,
void *),
struct buffer_head **bhp,
struct nilfs_bh_assoc *prev,
spinlock_t *lock)
{
int ret;
spin_lock(lock);
if (prev->bh && blkoff == prev->blkoff) {
get_bh(prev->bh);
*bhp = prev->bh;
spin_unlock(lock);
return 0;
}
spin_unlock(lock);
ret = nilfs_mdt_get_block(inode, blkoff, create, init_block, bhp);
if (!ret) {
spin_lock(lock);
/*
* The following code must be safe for change of the
* cache contents during the get block call.
*/
brelse(prev->bh);
get_bh(*bhp);
prev->bh = *bhp;
prev->blkoff = blkoff;
spin_unlock(lock);
}
return ret;
}
/**
* nilfs_palloc_get_desc_block - get buffer head of a group descriptor block
* @inode: inode of metadata file using this allocator
* @group: group number
* @create: create flag
* @bhp: pointer to store the resultant buffer head
*/
static int nilfs_palloc_get_desc_block(struct inode *inode,
unsigned long group,
int create, struct buffer_head **bhp)
{
struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
return nilfs_palloc_get_block(inode,
nilfs_palloc_desc_blkoff(inode, group),
create, nilfs_palloc_desc_block_init,
bhp, &cache->prev_desc, &cache->lock);
}
/**
* nilfs_palloc_get_bitmap_block - get buffer head of a bitmap block
* @inode: inode of metadata file using this allocator
* @group: group number
* @create: create flag
* @bhp: pointer to store the resultant buffer head
*/
static int nilfs_palloc_get_bitmap_block(struct inode *inode,
unsigned long group,
int create, struct buffer_head **bhp)
{
struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
return nilfs_palloc_get_block(inode,
nilfs_palloc_bitmap_blkoff(inode, group),
create, NULL, bhp,
&cache->prev_bitmap, &cache->lock);
}
/**
* nilfs_palloc_get_entry_block - get buffer head of an entry block
* @inode: inode of metadata file using this allocator
* @nr: serial number of the entry (e.g. inode number)
* @create: create flag
* @bhp: pointer to store the resultant buffer head
*/
int nilfs_palloc_get_entry_block(struct inode *inode, __u64 nr,
int create, struct buffer_head **bhp)
{
struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
return nilfs_palloc_get_block(inode,
nilfs_palloc_entry_blkoff(inode, nr),
create, NULL, bhp,
&cache->prev_entry, &cache->lock);
}
/**
* 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_block_get_entry - get kernel address of an entry
* @inode: inode of metadata file using this allocator
* @nr: serial number of the entry (e.g. inode number)
* @bh: buffer head of the buffer storing the entry block
* @kaddr: kernel address mapped for the page including the buffer
*/
void *nilfs_palloc_block_get_entry(const struct inode *inode, __u64 nr,
const struct buffer_head *bh, void *kaddr)
{
unsigned long entry_offset, group_offset;
nilfs_palloc_group(inode, nr, &group_offset);
entry_offset = group_offset % NILFS_MDT(inode)->mi_entries_per_block;
return kaddr + bh_offset(bh) +
entry_offset * NILFS_MDT(inode)->mi_entry_size;
}
/**
* nilfs_palloc_find_available_slot - find available slot in a group
* @inode: inode of metadata file using this allocator
* @group: group number
* @target: offset number of an entry in the group (start point)
* @bitmap: bitmap of the group
* @bsize: size in bits
*/
static int nilfs_palloc_find_available_slot(struct inode *inode,
unsigned long group,
unsigned long target,
unsigned char *bitmap,
int bsize)
{
int curr, pos, end, i;
if (target > 0) {
end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
if (end > bsize)
end = bsize;
pos = nilfs_find_next_zero_bit(bitmap, end, target);
if (pos < end &&
!nilfs_set_bit_atomic(
nilfs_mdt_bgl_lock(inode, group), pos, bitmap))
return pos;
} else
end = 0;
for (i = 0, curr = end;
i < bsize;
i += BITS_PER_LONG, curr += BITS_PER_LONG) {
/* wrap around */
if (curr >= bsize)
curr = 0;
while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
!= ~0UL) {
end = curr + BITS_PER_LONG;
if (end > bsize)
end = bsize;
pos = nilfs_find_next_zero_bit(bitmap, end, curr);
if ((pos < end) &&
!nilfs_set_bit_atomic(
nilfs_mdt_bgl_lock(inode, group), pos,
bitmap))
return pos;
}
}
return -ENOSPC;
}
/**
* 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_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;
}
/**
* nilfs_palloc_commit_alloc_entry - finish allocation of a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the allocation
*/
void nilfs_palloc_commit_alloc_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
mark_buffer_dirty(req->pr_bitmap_bh);
mark_buffer_dirty(req->pr_desc_bh);
nilfs_mdt_mark_dirty(inode);
brelse(req->pr_bitmap_bh);
brelse(req->pr_desc_bh);
}
/**
* nilfs_palloc_commit_free_entry - finish deallocating a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the removal
*/
void nilfs_palloc_commit_free_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
struct nilfs_palloc_group_desc *desc;
unsigned long group, group_offset;
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
desc_kaddr = kmap(req->pr_desc_bh->b_page);
desc = nilfs_palloc_block_get_group_desc(inode, group,
req->pr_desc_bh, desc_kaddr);
bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
group_offset, bitmap))
printk(KERN_WARNING "%s: entry number %llu already freed\n",
__func__, (unsigned long long)req->pr_entry_nr);
else
nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
kunmap(req->pr_bitmap_bh->b_page);
kunmap(req->pr_desc_bh->b_page);
mark_buffer_dirty(req->pr_desc_bh);
mark_buffer_dirty(req->pr_bitmap_bh);
nilfs_mdt_mark_dirty(inode);
brelse(req->pr_bitmap_bh);
brelse(req->pr_desc_bh);
}
/**
* nilfs_palloc_abort_alloc_entry - cancel allocation of a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the allocation
*/
void nilfs_palloc_abort_alloc_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
struct nilfs_palloc_group_desc *desc;
void *desc_kaddr, *bitmap_kaddr;
unsigned char *bitmap;
unsigned long group, group_offset;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
desc_kaddr = kmap(req->pr_desc_bh->b_page);
desc = nilfs_palloc_block_get_group_desc(inode, group,
req->pr_desc_bh, desc_kaddr);
bitmap_kaddr = kmap(req->pr_bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(req->pr_bitmap_bh);
if (!nilfs_clear_bit_atomic(nilfs_mdt_bgl_lock(inode, group),
group_offset, bitmap))
printk(KERN_WARNING "%s: entry number %llu already freed\n",
__func__, (unsigned long long)req->pr_entry_nr);
else
nilfs_palloc_group_desc_add_entries(inode, group, desc, 1);
kunmap(req->pr_bitmap_bh->b_page);
kunmap(req->pr_desc_bh->b_page);
brelse(req->pr_bitmap_bh);
brelse(req->pr_desc_bh);
req->pr_entry_nr = 0;
req->pr_bitmap_bh = NULL;
req->pr_desc_bh = NULL;
}
/**
* nilfs_palloc_prepare_free_entry - prepare to deallocate a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the removal
*/
int nilfs_palloc_prepare_free_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
struct buffer_head *desc_bh, *bitmap_bh;
unsigned long group, group_offset;
int ret;
group = nilfs_palloc_group(inode, req->pr_entry_nr, &group_offset);
ret = nilfs_palloc_get_desc_block(inode, group, 1, &desc_bh);
if (ret < 0)
return ret;
ret = nilfs_palloc_get_bitmap_block(inode, group, 1, &bitmap_bh);
if (ret < 0) {
brelse(desc_bh);
return ret;
}
req->pr_desc_bh = desc_bh;
req->pr_bitmap_bh = bitmap_bh;
return 0;
}
/**
* nilfs_palloc_abort_free_entry - cancel deallocating a persistent object
* @inode: inode of metadata file using this allocator
* @req: nilfs_palloc_req structure exchanged for the removal
*/
void nilfs_palloc_abort_free_entry(struct inode *inode,
struct nilfs_palloc_req *req)
{
brelse(req->pr_bitmap_bh);
brelse(req->pr_desc_bh);
req->pr_entry_nr = 0;
req->pr_bitmap_bh = NULL;
req->pr_desc_bh = NULL;
}
/**
* nilfs_palloc_group_is_in - judge if an entry is in a group
* @inode: inode of metadata file using this allocator
* @group: group number
* @nr: serial number of the entry (e.g. inode number)
*/
static int
nilfs_palloc_group_is_in(struct inode *inode, unsigned long group, __u64 nr)
{
__u64 first, last;
first = group * nilfs_palloc_entries_per_group(inode);
last = first + nilfs_palloc_entries_per_group(inode) - 1;
return (nr >= first) && (nr <= last);
}
/**
* nilfs_palloc_freev - deallocate a set of persistent objects
* @inode: inode of metadata file using this allocator
* @entry_nrs: array of entry numbers to be deallocated
* @nitems: number of entries stored in @entry_nrs
*/
int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
{
struct buffer_head *desc_bh, *bitmap_bh;
struct nilfs_palloc_group_desc *desc;
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
unsigned long group, group_offset;
int i, j, n, ret;
for (i = 0; i < nitems; i = j) {
group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
if (ret < 0)
return ret;
ret = nilfs_palloc_get_bitmap_block(inode, group, 0,
&bitmap_bh);
if (ret < 0) {
brelse(desc_bh);
return ret;
}
desc_kaddr = kmap(desc_bh->b_page);
desc = nilfs_palloc_block_get_group_desc(
inode, group, desc_bh, desc_kaddr);
bitmap_kaddr = kmap(bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
for (j = i, n = 0;
(j < nitems) && nilfs_palloc_group_is_in(inode, group,
entry_nrs[j]);
j++) {
nilfs_palloc_group(inode, entry_nrs[j], &group_offset);
if (!nilfs_clear_bit_atomic(
nilfs_mdt_bgl_lock(inode, group),
group_offset, bitmap)) {
printk(KERN_WARNING
"%s: entry number %llu already freed\n",
__func__,
(unsigned long long)entry_nrs[j]);
} else {
n++;
}
}
nilfs_palloc_group_desc_add_entries(inode, group, desc, n);
kunmap(bitmap_bh->b_page);
kunmap(desc_bh->b_page);
mark_buffer_dirty(desc_bh);
mark_buffer_dirty(bitmap_bh);
nilfs_mdt_mark_dirty(inode);
brelse(bitmap_bh);
brelse(desc_bh);
}
return 0;
}
void nilfs_palloc_setup_cache(struct inode *inode,
struct nilfs_palloc_cache *cache)
{
NILFS_MDT(inode)->mi_palloc_cache = cache;
spin_lock_init(&cache->lock);
}
void nilfs_palloc_clear_cache(struct inode *inode)
{
struct nilfs_palloc_cache *cache = NILFS_MDT(inode)->mi_palloc_cache;
spin_lock(&cache->lock);
brelse(cache->prev_desc.bh);
brelse(cache->prev_bitmap.bh);
brelse(cache->prev_entry.bh);
cache->prev_desc.bh = NULL;
cache->prev_bitmap.bh = NULL;
cache->prev_entry.bh = NULL;
spin_unlock(&cache->lock);
}
void nilfs_palloc_destroy_cache(struct inode *inode)
{
nilfs_palloc_clear_cache(inode);
NILFS_MDT(inode)->mi_palloc_cache = NULL;
}