- 根目录:
- fs
- logfs
- segment.c
/*
* fs/logfs/segment.c - Handling the Object Store
*
* As should be obvious for Linux kernel code, license is GPLv2
*
* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
*
* Object store or ostore makes up the complete device with exception of
* the superblock and journal areas. Apart from its own metadata it stores
* three kinds of objects: inodes, dentries and blocks, both data and indirect.
*/
#include "logfs.h"
#include <linux/slab.h>
static int logfs_mark_segment_bad(struct super_block *sb, u32 segno)
{
struct logfs_super *super = logfs_super(sb);
struct btree_head32 *head = &super->s_reserved_segments;
int err;
err = btree_insert32(head, segno, (void *)1, GFP_NOFS);
if (err)
return err;
logfs_super(sb)->s_bad_segments++;
/* FIXME: write to journal */
return 0;
}
int logfs_erase_segment(struct super_block *sb, u32 segno, int ensure_erase)
{
struct logfs_super *super = logfs_super(sb);
super->s_gec++;
return super->s_devops->erase(sb, (u64)segno << super->s_segshift,
super->s_segsize, ensure_erase);
}
static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes)
{
s32 ofs;
logfs_open_area(area, bytes);
ofs = area->a_used_bytes;
area->a_used_bytes += bytes;
BUG_ON(area->a_used_bytes >= logfs_super(area->a_sb)->s_segsize);
return dev_ofs(area->a_sb, area->a_segno, ofs);
}
static struct page *get_mapping_page(struct super_block *sb, pgoff_t index,
int use_filler)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
filler_t *filler = super->s_devops->readpage;
struct page *page;
BUG_ON(mapping_gfp_mask(mapping) & __GFP_FS);
if (use_filler)
page = read_cache_page(mapping, index, filler, sb);
else {
page = find_or_create_page(mapping, index, GFP_NOFS);
if (page)
unlock_page(page);
}
return page;
}
int __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len,
int use_filler)
{
pgoff_t index = ofs >> PAGE_SHIFT;
struct page *page;
long offset = ofs & (PAGE_SIZE-1);
long copylen;
/* Only logfs_wbuf_recover may use len==0 */
BUG_ON(!len && !use_filler);
do {
copylen = min((ulong)len, PAGE_SIZE - offset);
page = get_mapping_page(area->a_sb, index, use_filler);
if (IS_ERR(page))
return PTR_ERR(page);
BUG_ON(!page); /* FIXME: reserve a pool */
SetPageUptodate(page);
memcpy(page_address(page) + offset, buf, copylen);
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
}
page_cache_release(page);
buf += copylen;
len -= copylen;
offset = 0;
index++;
} while (len);
return 0;
}
static void pad_partial_page(struct logfs_area *area)
{
struct super_block *sb = area->a_sb;
struct page *page;
u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
pgoff_t index = ofs >> PAGE_SHIFT;
long offset = ofs & (PAGE_SIZE-1);
u32 len = PAGE_SIZE - offset;
if (len % PAGE_SIZE) {
page = get_mapping_page(sb, index, 0);
BUG_ON(!page); /* FIXME: reserve a pool */
memset(page_address(page) + offset, 0xff, len);
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
}
page_cache_release(page);
}
}
static void pad_full_pages(struct logfs_area *area)
{
struct super_block *sb = area->a_sb;
struct logfs_super *super = logfs_super(sb);
u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes);
u32 len = super->s_segsize - area->a_used_bytes;
pgoff_t index = PAGE_CACHE_ALIGN(ofs) >> PAGE_CACHE_SHIFT;
pgoff_t no_indizes = len >> PAGE_CACHE_SHIFT;
struct page *page;
while (no_indizes) {
page = get_mapping_page(sb, index, 0);
BUG_ON(!page); /* FIXME: reserve a pool */
SetPageUptodate(page);
memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
}
page_cache_release(page);
index++;
no_indizes--;
}
}
/*
* bdev_writeseg will write full pages. Memset the tail to prevent data leaks.
* Also make sure we allocate (and memset) all pages for final writeout.
*/
static void pad_wbuf(struct logfs_area *area, int final)
{
pad_partial_page(area);
if (final)
pad_full_pages(area);
}
/*
* We have to be careful with the alias tree. Since lookup is done by bix,
* it needs to be normalized, so 14, 15, 16, etc. all match when dealing with
* indirect blocks. So always use it through accessor functions.
*/
static void *alias_tree_lookup(struct super_block *sb, u64 ino, u64 bix,
level_t level)
{
struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
pgoff_t index = logfs_pack_index(bix, level);
return btree_lookup128(head, ino, index);
}
static int alias_tree_insert(struct super_block *sb, u64 ino, u64 bix,
level_t level, void *val)
{
struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree;
pgoff_t index = logfs_pack_index(bix, level);
return btree_insert128(head, ino, index, val, GFP_NOFS);
}
static int btree_write_alias(struct super_block *sb, struct logfs_block *block,
write_alias_t *write_one_alias)
{
struct object_alias_item *item;
int err;
list_for_each_entry(item, &block->item_list, list) {
err = write_alias_journal(sb, block->ino, block->bix,
block->level, item->child_no, item->val);
if (err)
return err;
}
return 0;
}
static struct logfs_block_ops btree_block_ops = {
.write_block = btree_write_block,
.free_block = __free_block,
.write_alias = btree_write_alias,
};
int logfs_load_object_aliases(struct super_block *sb,
struct logfs_obj_alias *oa, int count)
{
struct logfs_super *super = logfs_super(sb);
struct logfs_block *block;
struct object_alias_item *item;
u64 ino, bix;
level_t level;
int i, err;
super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
count /= sizeof(*oa);
for (i = 0; i < count; i++) {
item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
if (!item)
return -ENOMEM;
memset(item, 0, sizeof(*item));
super->s_no_object_aliases++;
item->val = oa[i].val;
item->child_no = be16_to_cpu(oa[i].child_no);
ino = be64_to_cpu(oa[i].ino);
bix = be64_to_cpu(oa[i].bix);
level = LEVEL(oa[i].level);
log_aliases("logfs_load_object_aliases(%llx, %llx, %x, %x) %llx\n",
ino, bix, level, item->child_no,
be64_to_cpu(item->val));
block = alias_tree_lookup(sb, ino, bix, level);
if (!block) {
block = __alloc_block(sb, ino, bix, level);
block->ops = &btree_block_ops;
err = alias_tree_insert(sb, ino, bix, level, block);
BUG_ON(err); /* mempool empty */
}
if (test_and_set_bit(item->child_no, block->alias_map)) {
printk(KERN_ERR"LogFS: Alias collision detected\n");
return -EIO;
}
list_move_tail(&block->alias_list, &super->s_object_alias);
list_add(&item->list, &block->item_list);
}
return 0;
}
static void kill_alias(void *_block, unsigned long ignore0,
u64 ignore1, u64 ignore2, size_t ignore3)
{
struct logfs_block *block = _block;
struct super_block *sb = block->sb;
struct logfs_super *super = logfs_super(sb);
struct object_alias_item *item;
while (!list_empty(&block->item_list)) {
item = list_entry(block->item_list.next, typeof(*item), list);
list_del(&item->list);
mempool_free(item, super->s_alias_pool);
}
block->ops->free_block(sb, block);
}
static int obj_type(struct inode *inode, level_t level)
{
if (level == 0) {
if (S_ISDIR(inode->i_mode))
return OBJ_DENTRY;
if (inode->i_ino == LOGFS_INO_MASTER)
return OBJ_INODE;
}
return OBJ_BLOCK;
}
static int obj_len(struct super_block *sb, int obj_type)
{
switch (obj_type) {
case OBJ_DENTRY:
return sizeof(struct logfs_disk_dentry);
case OBJ_INODE:
return sizeof(struct logfs_disk_inode);
case OBJ_BLOCK:
return sb->s_blocksize;
default:
BUG();
}
}
static int __logfs_segment_write(struct inode *inode, void *buf,
struct logfs_shadow *shadow, int type, int len, int compr)
{
struct logfs_area *area;
struct super_block *sb = inode->i_sb;
s64 ofs;
struct logfs_object_header h;
int acc_len;
if (shadow->gc_level == 0)
acc_len = len;
else
acc_len = obj_len(sb, type);
area = get_area(sb, shadow->gc_level);
ofs = logfs_get_free_bytes(area, len + LOGFS_OBJECT_HEADERSIZE);
LOGFS_BUG_ON(ofs <= 0, sb);
/*
* Order is important. logfs_get_free_bytes(), by modifying the
* segment file, may modify the content of the very page we're about
* to write now. Which is fine, as long as the calculated crc and
* written data still match. So do the modifications _before_
* calculating the crc.
*/
h.len = cpu_to_be16(len);
h.type = type;
h.compr = compr;
h.ino = cpu_to_be64(inode->i_ino);
h.bix = cpu_to_be64(shadow->bix);
h.crc = logfs_crc32(&h, sizeof(h) - 4, 4);
h.data_crc = logfs_crc32(buf, len, 0);
logfs_buf_write(area, ofs, &h, sizeof(h));
logfs_buf_write(area, ofs + LOGFS_OBJECT_HEADERSIZE, buf, len);
shadow->new_ofs = ofs;
shadow->new_len = acc_len + LOGFS_OBJECT_HEADERSIZE;
return 0;
}
static s64 logfs_segment_write_compress(struct inode *inode, void *buf,
struct logfs_shadow *shadow, int type, int len)
{
struct super_block *sb = inode->i_sb;
void *compressor_buf = logfs_super(sb)->s_compressed_je;
ssize_t compr_len;
int ret;
mutex_lock(&logfs_super(sb)->s_journal_mutex);
compr_len = logfs_compress(buf, compressor_buf, len, len);
if (compr_len >= 0) {
ret = __logfs_segment_write(inode, compressor_buf, shadow,
type, compr_len, COMPR_ZLIB);
} else {
ret = __logfs_segment_write(inode, buf, shadow, type, len,
COMPR_NONE);
}
mutex_unlock(&logfs_super(sb)->s_journal_mutex);
return ret;
}
/**
* logfs_segment_write - write data block to object store
* @inode: inode containing data
*
* Returns an errno or zero.
*/
int logfs_segment_write(struct inode *inode, struct page *page,
struct logfs_shadow *shadow)
{
struct super_block *sb = inode->i_sb;
struct logfs_super *super = logfs_super(sb);
int do_compress, type, len;
int ret;
void *buf;
super->s_flags |= LOGFS_SB_FLAG_DIRTY;
BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED;
if (shadow->gc_level != 0) {
/* temporarily disable compression for indirect blocks */
do_compress = 0;
}
type = obj_type(inode, shrink_level(shadow->gc_level));
len = obj_len(sb, type);
buf = kmap(page);
if (do_compress)
ret = logfs_segment_write_compress(inode, buf, shadow, type,
len);
else
ret = __logfs_segment_write(inode, buf, shadow, type, len,
COMPR_NONE);
kunmap(page);
log_segment("logfs_segment_write(%llx, %llx, %x) %llx->%llx %x->%x\n",
shadow->ino, shadow->bix, shadow->gc_level,
shadow->old_ofs, shadow->new_ofs,
shadow->old_len, shadow->new_len);
/* this BUG_ON did catch a locking bug. useful */
BUG_ON(!(shadow->new_ofs & (super->s_segsize - 1)));
return ret;
}
int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf)
{
pgoff_t index = ofs >> PAGE_SHIFT;
struct page *page;
long offset = ofs & (PAGE_SIZE-1);
long copylen;
while (len) {
copylen = min((ulong)len, PAGE_SIZE - offset);
page = get_mapping_page(sb, index, 1);
if (IS_ERR(page))
return PTR_ERR(page);
memcpy(buf, page_address(page) + offset, copylen);
page_cache_release(page);
buf += copylen;
len -= copylen;
offset = 0;
index++;
}
return 0;
}
/*
* The "position" of indirect blocks is ambiguous. It can be the position
* of any data block somewhere behind this indirect block. So we need to
* normalize the positions through logfs_block_mask() before comparing.
*/
static int check_pos(struct super_block *sb, u64 pos1, u64 pos2, level_t level)
{
return (pos1 & logfs_block_mask(sb, level)) !=
(pos2 & logfs_block_mask(sb, level));
}
#if 0
static int read_seg_header(struct super_block *sb, u64 ofs,
struct logfs_segment_header *sh)
{
__be32 crc;
int err;
err = wbuf_read(sb, ofs, sizeof(*sh), sh);
if (err)
return err;
crc = logfs_crc32(sh, sizeof(*sh), 4);
if (crc != sh->crc) {
printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
"got %x\n", ofs, be32_to_cpu(sh->crc),
be32_to_cpu(crc));
return -EIO;
}
return 0;
}
#endif
static int read_obj_header(struct super_block *sb, u64 ofs,
struct logfs_object_header *oh)
{
__be32 crc;
int err;
err = wbuf_read(sb, ofs, sizeof(*oh), oh);
if (err)
return err;
crc = logfs_crc32(oh, sizeof(*oh) - 4, 4);
if (crc != oh->crc) {
printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, "
"got %x\n", ofs, be32_to_cpu(oh->crc),
be32_to_cpu(crc));
return -EIO;
}
return 0;
}
static void move_btree_to_page(struct inode *inode, struct page *page,
__be64 *data)
{
struct super_block *sb = inode->i_sb;
struct logfs_super *super = logfs_super(sb);
struct btree_head128 *head = &super->s_object_alias_tree;
struct logfs_block *block;
struct object_alias_item *item, *next;
if (!(super->s_flags & LOGFS_SB_FLAG_OBJ_ALIAS))
return;
block = btree_remove128(head, inode->i_ino, page->index);
if (!block)
return;
log_blockmove("move_btree_to_page(%llx, %llx, %x)\n",
block->ino, block->bix, block->level);
list_for_each_entry_safe(item, next, &block->item_list, list) {
data[item->child_no] = item->val;
list_del(&item->list);
mempool_free(item, super->s_alias_pool);
}
block->page = page;
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
set_page_private(page, (unsigned long) block);
}
block->ops = &indirect_block_ops;
initialize_block_counters(page, block, data, 0);
}
/*
* This silences a false, yet annoying gcc warning. I hate it when my editor
* jumps into bitops.h each time I recompile this file.
* TODO: Complain to gcc folks about this and upgrade compiler.
*/
static unsigned long fnb(const unsigned long *addr,
unsigned long size, unsigned long offset)
{
return find_next_bit(addr, size, offset);
}
void move_page_to_btree(struct page *page)
{
struct logfs_block *block = logfs_block(page);
struct super_block *sb = block->sb;
struct logfs_super *super = logfs_super(sb);
struct object_alias_item *item;
unsigned long pos;
__be64 *child;
int err;
if (super->s_flags & LOGFS_SB_FLAG_SHUTDOWN) {
block->ops->free_block(sb, block);
return;
}
log_blockmove("move_page_to_btree(%llx, %llx, %x)\n",
block->ino, block->bix, block->level);
super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS;
for (pos = 0; ; pos++) {
pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
if (pos >= LOGFS_BLOCK_FACTOR)
break;
item = mempool_alloc(super->s_alias_pool, GFP_NOFS);
BUG_ON(!item); /* mempool empty */
memset(item, 0, sizeof(*item));
child = kmap_atomic(page);
item->val = child[pos];
kunmap_atomic(child);
item->child_no = pos;
list_add(&item->list, &block->item_list);
}
block->page = NULL;
if (PagePrivate(page)) {
ClearPagePrivate(page);
page_cache_release(page);
set_page_private(page, 0);
}
block->ops = &btree_block_ops;
err = alias_tree_insert(block->sb, block->ino, block->bix, block->level,
block);
BUG_ON(err); /* mempool empty */
ClearPageUptodate(page);
}
static int __logfs_segment_read(struct inode *inode, void *buf,
u64 ofs, u64 bix, level_t level)
{
struct super_block *sb = inode->i_sb;
void *compressor_buf = logfs_super(sb)->s_compressed_je;
struct logfs_object_header oh;
__be32 crc;
u16 len;
int err, block_len;
block_len = obj_len(sb, obj_type(inode, level));
err = read_obj_header(sb, ofs, &oh);
if (err)
goto out_err;
err = -EIO;
if (be64_to_cpu(oh.ino) != inode->i_ino
|| check_pos(sb, be64_to_cpu(oh.bix), bix, level)) {
printk(KERN_ERR"LOGFS: (ino, bix) don't match at %llx: "
"expected (%lx, %llx), got (%llx, %llx)\n",
ofs, inode->i_ino, bix,
be64_to_cpu(oh.ino), be64_to_cpu(oh.bix));
goto out_err;
}
len = be16_to_cpu(oh.len);
switch (oh.compr) {
case COMPR_NONE:
err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, buf);
if (err)
goto out_err;
crc = logfs_crc32(buf, len, 0);
if (crc != oh.data_crc) {
printk(KERN_ERR"LOGFS: uncompressed data crc error at "
"%llx: expected %x, got %x\n", ofs,
be32_to_cpu(oh.data_crc),
be32_to_cpu(crc));
goto out_err;
}
break;
case COMPR_ZLIB:
mutex_lock(&logfs_super(sb)->s_journal_mutex);
err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len,
compressor_buf);
if (err) {
mutex_unlock(&logfs_super(sb)->s_journal_mutex);
goto out_err;
}
crc = logfs_crc32(compressor_buf, len, 0);
if (crc != oh.data_crc) {
printk(KERN_ERR"LOGFS: compressed data crc error at "
"%llx: expected %x, got %x\n", ofs,
be32_to_cpu(oh.data_crc),
be32_to_cpu(crc));
mutex_unlock(&logfs_super(sb)->s_journal_mutex);
goto out_err;
}
err = logfs_uncompress(compressor_buf, buf, len, block_len);
mutex_unlock(&logfs_super(sb)->s_journal_mutex);
if (err) {
printk(KERN_ERR"LOGFS: uncompress error at %llx\n", ofs);
goto out_err;
}
break;
default:
LOGFS_BUG(sb);
err = -EIO;
goto out_err;
}
return 0;
out_err:
logfs_set_ro(sb);
printk(KERN_ERR"LOGFS: device is read-only now\n");
LOGFS_BUG(sb);
return err;
}
/**
* logfs_segment_read - read data block from object store
* @inode: inode containing data
* @buf: data buffer
* @ofs: physical data offset
* @bix: block index
* @level: block level
*
* Returns 0 on success or a negative errno.
*/
int logfs_segment_read(struct inode *inode, struct page *page,
u64 ofs, u64 bix, level_t level)
{
int err;
void *buf;
if (PageUptodate(page))
return 0;
ofs &= ~LOGFS_FULLY_POPULATED;
buf = kmap(page);
err = __logfs_segment_read(inode, buf, ofs, bix, level);
if (!err) {
move_btree_to_page(inode, page, buf);
SetPageUptodate(page);
}
kunmap(page);
log_segment("logfs_segment_read(%lx, %llx, %x) %llx (%d)\n",
inode->i_ino, bix, level, ofs, err);
return err;
}
int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow)
{
struct super_block *sb = inode->i_sb;
struct logfs_super *super = logfs_super(sb);
struct logfs_object_header h;
u16 len;
int err;
super->s_flags |= LOGFS_SB_FLAG_DIRTY;
BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN);
BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED);
if (!shadow->old_ofs)
return 0;
log_segment("logfs_segment_delete(%llx, %llx, %x) %llx->%llx %x->%x\n",
shadow->ino, shadow->bix, shadow->gc_level,
shadow->old_ofs, shadow->new_ofs,
shadow->old_len, shadow->new_len);
err = read_obj_header(sb, shadow->old_ofs, &h);
LOGFS_BUG_ON(err, sb);
LOGFS_BUG_ON(be64_to_cpu(h.ino) != inode->i_ino, sb);
LOGFS_BUG_ON(check_pos(sb, shadow->bix, be64_to_cpu(h.bix),
shrink_level(shadow->gc_level)), sb);
if (shadow->gc_level == 0)
len = be16_to_cpu(h.len);
else
len = obj_len(sb, h.type);
shadow->old_len = len + sizeof(h);
return 0;
}
void freeseg(struct super_block *sb, u32 segno)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping = super->s_mapping_inode->i_mapping;
struct page *page;
u64 ofs, start, end;
start = dev_ofs(sb, segno, 0);
end = dev_ofs(sb, segno + 1, 0);
for (ofs = start; ofs < end; ofs += PAGE_SIZE) {
page = find_get_page(mapping, ofs >> PAGE_SHIFT);
if (!page)
continue;
if (PagePrivate(page)) {
ClearPagePrivate(page);
page_cache_release(page);
}
page_cache_release(page);
}
}
int logfs_open_area(struct logfs_area *area, size_t bytes)
{
struct super_block *sb = area->a_sb;
struct logfs_super *super = logfs_super(sb);
int err, closed = 0;
if (area->a_is_open && area->a_used_bytes + bytes <= super->s_segsize)
return 0;
if (area->a_is_open) {
u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
u32 len = super->s_segsize - area->a_written_bytes;
log_gc("logfs_close_area(%x)\n", area->a_segno);
pad_wbuf(area, 1);
super->s_devops->writeseg(area->a_sb, ofs, len);
freeseg(sb, area->a_segno);
closed = 1;
}
area->a_used_bytes = 0;
area->a_written_bytes = 0;
again:
area->a_ops->get_free_segment(area);
area->a_ops->get_erase_count(area);
log_gc("logfs_open_area(%x, %x)\n", area->a_segno, area->a_level);
err = area->a_ops->erase_segment(area);
if (err) {
printk(KERN_WARNING "LogFS: Error erasing segment %x\n",
area->a_segno);
logfs_mark_segment_bad(sb, area->a_segno);
goto again;
}
area->a_is_open = 1;
return closed;
}
void logfs_sync_area(struct logfs_area *area)
{
struct super_block *sb = area->a_sb;
struct logfs_super *super = logfs_super(sb);
u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
u32 len = (area->a_used_bytes - area->a_written_bytes);
if (super->s_writesize)
len &= ~(super->s_writesize - 1);
if (len == 0)
return;
pad_wbuf(area, 0);
super->s_devops->writeseg(sb, ofs, len);
area->a_written_bytes += len;
}
void logfs_sync_segments(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
int i;
for_each_area(i)
logfs_sync_area(super->s_area[i]);
}
/*
* Pick a free segment to be used for this area. Effectively takes a
* candidate from the free list (not really a candidate anymore).
*/
static void ostore_get_free_segment(struct logfs_area *area)
{
struct super_block *sb = area->a_sb;
struct logfs_super *super = logfs_super(sb);
if (super->s_free_list.count == 0) {
printk(KERN_ERR"LOGFS: ran out of free segments\n");
LOGFS_BUG(sb);
}
area->a_segno = get_best_cand(sb, &super->s_free_list, NULL);
}
static void ostore_get_erase_count(struct logfs_area *area)
{
struct logfs_segment_entry se;
u32 ec_level;
logfs_get_segment_entry(area->a_sb, area->a_segno, &se);
BUG_ON(se.ec_level == cpu_to_be32(BADSEG) ||
se.valid == cpu_to_be32(RESERVED));
ec_level = be32_to_cpu(se.ec_level);
area->a_erase_count = (ec_level >> 4) + 1;
}
static int ostore_erase_segment(struct logfs_area *area)
{
struct super_block *sb = area->a_sb;
struct logfs_segment_header sh;
u64 ofs;
int err;
err = logfs_erase_segment(sb, area->a_segno, 0);
if (err)
return err;
sh.pad = 0;
sh.type = SEG_OSTORE;
sh.level = (__force u8)area->a_level;
sh.segno = cpu_to_be32(area->a_segno);
sh.ec = cpu_to_be32(area->a_erase_count);
sh.gec = cpu_to_be64(logfs_super(sb)->s_gec);
sh.crc = logfs_crc32(&sh, sizeof(sh), 4);
logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count,
area->a_level);
ofs = dev_ofs(sb, area->a_segno, 0);
area->a_used_bytes = sizeof(sh);
logfs_buf_write(area, ofs, &sh, sizeof(sh));
return 0;
}
static const struct logfs_area_ops ostore_area_ops = {
.get_free_segment = ostore_get_free_segment,
.get_erase_count = ostore_get_erase_count,
.erase_segment = ostore_erase_segment,
};
static void free_area(struct logfs_area *area)
{
if (area)
freeseg(area->a_sb, area->a_segno);
kfree(area);
}
void free_areas(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
int i;
for_each_area(i)
free_area(super->s_area[i]);
free_area(super->s_journal_area);
}
static struct logfs_area *alloc_area(struct super_block *sb)
{
struct logfs_area *area;
area = kzalloc(sizeof(*area), GFP_KERNEL);
if (!area)
return NULL;
area->a_sb = sb;
return area;
}
static void map_invalidatepage(struct page *page, unsigned int o,
unsigned int l)
{
return;
}
static int map_releasepage(struct page *page, gfp_t g)
{
/* Don't release these pages */
return 0;
}
static const struct address_space_operations mapping_aops = {
.invalidatepage = map_invalidatepage,
.releasepage = map_releasepage,
.set_page_dirty = __set_page_dirty_nobuffers,
};
int logfs_init_mapping(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
struct address_space *mapping;
struct inode *inode;
inode = logfs_new_meta_inode(sb, LOGFS_INO_MAPPING);
if (IS_ERR(inode))
return PTR_ERR(inode);
super->s_mapping_inode = inode;
mapping = inode->i_mapping;
mapping->a_ops = &mapping_aops;
/* Would it be possible to use __GFP_HIGHMEM as well? */
mapping_set_gfp_mask(mapping, GFP_NOFS);
return 0;
}
int logfs_init_areas(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
int i = -1;
super->s_alias_pool = mempool_create_kmalloc_pool(600,
sizeof(struct object_alias_item));
if (!super->s_alias_pool)
return -ENOMEM;
super->s_journal_area = alloc_area(sb);
if (!super->s_journal_area)
goto err;
for_each_area(i) {
super->s_area[i] = alloc_area(sb);
if (!super->s_area[i])
goto err;
super->s_area[i]->a_level = GC_LEVEL(i);
super->s_area[i]->a_ops = &ostore_area_ops;
}
btree_init_mempool128(&super->s_object_alias_tree,
super->s_btree_pool);
return 0;
err:
for (i--; i >= 0; i--)
free_area(super->s_area[i]);
free_area(super->s_journal_area);
logfs_mempool_destroy(super->s_alias_pool);
return -ENOMEM;
}
void logfs_cleanup_areas(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias);
}