- 根目录:
- fs
- logfs
- readwrite.c
/*
* fs/logfs/readwrite.c
*
* As should be obvious for Linux kernel code, license is GPLv2
*
* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
*
*
* Actually contains five sets of very similar functions:
* read read blocks from a file
* seek_hole find next hole
* seek_data find next data block
* valid check whether a block still belongs to a file
* write write blocks to a file
* delete delete a block (for directories and ifile)
* rewrite move existing blocks of a file to a new location (gc helper)
* truncate truncate a file
*/
#include "logfs.h"
#include <linux/sched.h>
#include <linux/slab.h>
static u64 adjust_bix(u64 bix, level_t level)
{
switch (level) {
case 0:
return bix;
case LEVEL(1):
return max_t(u64, bix, I0_BLOCKS);
case LEVEL(2):
return max_t(u64, bix, I1_BLOCKS);
case LEVEL(3):
return max_t(u64, bix, I2_BLOCKS);
case LEVEL(4):
return max_t(u64, bix, I3_BLOCKS);
case LEVEL(5):
return max_t(u64, bix, I4_BLOCKS);
default:
WARN_ON(1);
return bix;
}
}
static inline u64 maxbix(u8 height)
{
return 1ULL << (LOGFS_BLOCK_BITS * height);
}
/**
* The inode address space is cut in two halves. Lower half belongs to data
* pages, upper half to indirect blocks. If the high bit (INDIRECT_BIT) is
* set, the actual block index (bix) and level can be derived from the page
* index.
*
* The lowest three bits of the block index are set to 0 after packing and
* unpacking. Since the lowest n bits (9 for 4KiB blocksize) are ignored
* anyway this is harmless.
*/
#define ARCH_SHIFT (BITS_PER_LONG - 32)
#define INDIRECT_BIT (0x80000000UL << ARCH_SHIFT)
#define LEVEL_SHIFT (28 + ARCH_SHIFT)
static inline pgoff_t first_indirect_block(void)
{
return INDIRECT_BIT | (1ULL << LEVEL_SHIFT);
}
pgoff_t logfs_pack_index(u64 bix, level_t level)
{
pgoff_t index;
BUG_ON(bix >= INDIRECT_BIT);
if (level == 0)
return bix;
index = INDIRECT_BIT;
index |= (__force long)level << LEVEL_SHIFT;
index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS);
return index;
}
void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level)
{
u8 __level;
if (!(index & INDIRECT_BIT)) {
*bix = index;
*level = 0;
return;
}
__level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT;
*level = LEVEL(__level);
*bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT;
*bix = adjust_bix(*bix, *level);
return;
}
#undef ARCH_SHIFT
#undef INDIRECT_BIT
#undef LEVEL_SHIFT
/*
* Time is stored as nanoseconds since the epoch.
*/
static struct timespec be64_to_timespec(__be64 betime)
{
return ns_to_timespec(be64_to_cpu(betime));
}
static __be64 timespec_to_be64(struct timespec tsp)
{
return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec);
}
static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode)
{
struct logfs_inode *li = logfs_inode(inode);
int i;
inode->i_mode = be16_to_cpu(di->di_mode);
li->li_height = di->di_height;
li->li_flags = be32_to_cpu(di->di_flags);
i_uid_write(inode, be32_to_cpu(di->di_uid));
i_gid_write(inode, be32_to_cpu(di->di_gid));
inode->i_size = be64_to_cpu(di->di_size);
logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes));
inode->i_atime = be64_to_timespec(di->di_atime);
inode->i_ctime = be64_to_timespec(di->di_ctime);
inode->i_mtime = be64_to_timespec(di->di_mtime);
set_nlink(inode, be32_to_cpu(di->di_refcount));
inode->i_generation = be32_to_cpu(di->di_generation);
switch (inode->i_mode & S_IFMT) {
case S_IFSOCK: /* fall through */
case S_IFBLK: /* fall through */
case S_IFCHR: /* fall through */
case S_IFIFO:
inode->i_rdev = be64_to_cpu(di->di_data[0]);
break;
case S_IFDIR: /* fall through */
case S_IFREG: /* fall through */
case S_IFLNK:
for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
li->li_data[i] = be64_to_cpu(di->di_data[i]);
break;
default:
BUG();
}
}
static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di)
{
struct logfs_inode *li = logfs_inode(inode);
int i;
di->di_mode = cpu_to_be16(inode->i_mode);
di->di_height = li->li_height;
di->di_pad = 0;
di->di_flags = cpu_to_be32(li->li_flags);
di->di_uid = cpu_to_be32(i_uid_read(inode));
di->di_gid = cpu_to_be32(i_gid_read(inode));
di->di_size = cpu_to_be64(i_size_read(inode));
di->di_used_bytes = cpu_to_be64(li->li_used_bytes);
di->di_atime = timespec_to_be64(inode->i_atime);
di->di_ctime = timespec_to_be64(inode->i_ctime);
di->di_mtime = timespec_to_be64(inode->i_mtime);
di->di_refcount = cpu_to_be32(inode->i_nlink);
di->di_generation = cpu_to_be32(inode->i_generation);
switch (inode->i_mode & S_IFMT) {
case S_IFSOCK: /* fall through */
case S_IFBLK: /* fall through */
case S_IFCHR: /* fall through */
case S_IFIFO:
di->di_data[0] = cpu_to_be64(inode->i_rdev);
break;
case S_IFDIR: /* fall through */
case S_IFREG: /* fall through */
case S_IFLNK:
for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++)
di->di_data[i] = cpu_to_be64(li->li_data[i]);
break;
default:
BUG();
}
}
static void __logfs_set_blocks(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct logfs_inode *li = logfs_inode(inode);
inode->i_blocks = ULONG_MAX;
if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX)
inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9;
}
void logfs_set_blocks(struct inode *inode, u64 bytes)
{
struct logfs_inode *li = logfs_inode(inode);
li->li_used_bytes = bytes;
__logfs_set_blocks(inode);
}
static void prelock_page(struct super_block *sb, struct page *page, int lock)
{
struct logfs_super *super = logfs_super(sb);
BUG_ON(!PageLocked(page));
if (lock) {
BUG_ON(PagePreLocked(page));
SetPagePreLocked(page);
} else {
/* We are in GC path. */
if (PagePreLocked(page))
super->s_lock_count++;
else
SetPagePreLocked(page);
}
}
static void preunlock_page(struct super_block *sb, struct page *page, int lock)
{
struct logfs_super *super = logfs_super(sb);
BUG_ON(!PageLocked(page));
if (lock)
ClearPagePreLocked(page);
else {
/* We are in GC path. */
BUG_ON(!PagePreLocked(page));
if (super->s_lock_count)
super->s_lock_count--;
else
ClearPagePreLocked(page);
}
}
/*
* Logfs is prone to an AB-BA deadlock where one task tries to acquire
* s_write_mutex with a locked page and GC tries to get that page while holding
* s_write_mutex.
* To solve this issue logfs will ignore the page lock iff the page in question
* is waiting for s_write_mutex. We annotate this fact by setting PG_pre_locked
* in addition to PG_locked.
*/
void logfs_get_wblocks(struct super_block *sb, struct page *page, int lock)
{
struct logfs_super *super = logfs_super(sb);
if (page)
prelock_page(sb, page, lock);
if (lock) {
mutex_lock(&super->s_write_mutex);
logfs_gc_pass(sb);
/* FIXME: We also have to check for shadowed space
* and mempool fill grade */
}
}
void logfs_put_wblocks(struct super_block *sb, struct page *page, int lock)
{
struct logfs_super *super = logfs_super(sb);
if (page)
preunlock_page(sb, page, lock);
/* Order matters - we must clear PG_pre_locked before releasing
* s_write_mutex or we could race against another task. */
if (lock)
mutex_unlock(&super->s_write_mutex);
}
static struct page *logfs_get_read_page(struct inode *inode, u64 bix,
level_t level)
{
return find_or_create_page(inode->i_mapping,
logfs_pack_index(bix, level), GFP_NOFS);
}
static void logfs_put_read_page(struct page *page)
{
unlock_page(page);
page_cache_release(page);
}
static void logfs_lock_write_page(struct page *page)
{
int loop = 0;
while (unlikely(!trylock_page(page))) {
if (loop++ > 0x1000) {
/* Has been observed once so far... */
printk(KERN_ERR "stack at %p\n", &loop);
BUG();
}
if (PagePreLocked(page)) {
/* Holder of page lock is waiting for us, it
* is safe to use this page. */
break;
}
/* Some other process has this page locked and has
* nothing to do with us. Wait for it to finish.
*/
schedule();
}
BUG_ON(!PageLocked(page));
}
static struct page *logfs_get_write_page(struct inode *inode, u64 bix,
level_t level)
{
struct address_space *mapping = inode->i_mapping;
pgoff_t index = logfs_pack_index(bix, level);
struct page *page;
int err;
repeat:
page = find_get_page(mapping, index);
if (!page) {
page = __page_cache_alloc(GFP_NOFS);
if (!page)
return NULL;
err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS);
if (unlikely(err)) {
page_cache_release(page);
if (err == -EEXIST)
goto repeat;
return NULL;
}
} else logfs_lock_write_page(page);
BUG_ON(!PageLocked(page));
return page;
}
static void logfs_unlock_write_page(struct page *page)
{
if (!PagePreLocked(page))
unlock_page(page);
}
static void logfs_put_write_page(struct page *page)
{
logfs_unlock_write_page(page);
page_cache_release(page);
}
static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level,
int rw)
{
if (rw == READ)
return logfs_get_read_page(inode, bix, level);
else
return logfs_get_write_page(inode, bix, level);
}
static void logfs_put_page(struct page *page, int rw)
{
if (rw == READ)
logfs_put_read_page(page);
else
logfs_put_write_page(page);
}
static unsigned long __get_bits(u64 val, int skip, int no)
{
u64 ret = val;
ret >>= skip * no;
ret <<= 64 - no;
ret >>= 64 - no;
return ret;
}
static unsigned long get_bits(u64 val, level_t skip)
{
return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS);
}
static inline void init_shadow_tree(struct super_block *sb,
struct shadow_tree *tree)
{
struct logfs_super *super = logfs_super(sb);
btree_init_mempool64(&tree->new, super->s_btree_pool);
btree_init_mempool64(&tree->old, super->s_btree_pool);
}
static void indirect_write_block(struct logfs_block *block)
{
struct page *page;
struct inode *inode;
int ret;
page = block->page;
inode = page->mapping->host;
logfs_lock_write_page(page);
ret = logfs_write_buf(inode, page, 0);
logfs_unlock_write_page(page);
/*
* This needs some rework. Unless you want your filesystem to run
* completely synchronously (you don't), the filesystem will always
* report writes as 'successful' before the actual work has been
* done. The actual work gets done here and this is where any errors
* will show up. And there isn't much we can do about it, really.
*
* Some attempts to fix the errors (move from bad blocks, retry io,...)
* have already been done, so anything left should be either a broken
* device or a bug somewhere in logfs itself. Being relatively new,
* the odds currently favor a bug, so for now the line below isn't
* entirely tasteles.
*/
BUG_ON(ret);
}
static void inode_write_block(struct logfs_block *block)
{
struct inode *inode;
int ret;
inode = block->inode;
if (inode->i_ino == LOGFS_INO_MASTER)
logfs_write_anchor(inode->i_sb);
else {
ret = __logfs_write_inode(inode, NULL, 0);
/* see indirect_write_block comment */
BUG_ON(ret);
}
}
/*
* 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);
}
static __be64 inode_val0(struct inode *inode)
{
struct logfs_inode *li = logfs_inode(inode);
u64 val;
/*
* Explicit shifting generates good code, but must match the format
* of the structure. Add some paranoia just in case.
*/
BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0);
BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2);
BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4);
val = (u64)inode->i_mode << 48 |
(u64)li->li_height << 40 |
(u64)li->li_flags;
return cpu_to_be64(val);
}
static int inode_write_alias(struct super_block *sb,
struct logfs_block *block, write_alias_t *write_one_alias)
{
struct inode *inode = block->inode;
struct logfs_inode *li = logfs_inode(inode);
unsigned long pos;
u64 ino , bix;
__be64 val;
level_t level;
int err;
for (pos = 0; ; pos++) {
pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS)
return 0;
switch (pos) {
case INODE_HEIGHT_OFS:
val = inode_val0(inode);
break;
case INODE_USED_OFS:
val = cpu_to_be64(li->li_used_bytes);
break;
case INODE_SIZE_OFS:
val = cpu_to_be64(i_size_read(inode));
break;
case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1:
val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]);
break;
default:
BUG();
}
ino = LOGFS_INO_MASTER;
bix = inode->i_ino;
level = LEVEL(0);
err = write_one_alias(sb, ino, bix, level, pos, val);
if (err)
return err;
}
}
static int indirect_write_alias(struct super_block *sb,
struct logfs_block *block, write_alias_t *write_one_alias)
{
unsigned long pos;
struct page *page = block->page;
u64 ino , bix;
__be64 *child, val;
level_t level;
int err;
for (pos = 0; ; pos++) {
pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos);
if (pos >= LOGFS_BLOCK_FACTOR)
return 0;
ino = page->mapping->host->i_ino;
logfs_unpack_index(page->index, &bix, &level);
child = kmap_atomic(page);
val = child[pos];
kunmap_atomic(child);
err = write_one_alias(sb, ino, bix, level, pos, val);
if (err)
return err;
}
}
int logfs_write_obj_aliases_pagecache(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
struct logfs_block *block;
int err;
list_for_each_entry(block, &super->s_object_alias, alias_list) {
err = block->ops->write_alias(sb, block, write_alias_journal);
if (err)
return err;
}
return 0;
}
void __free_block(struct super_block *sb, struct logfs_block *block)
{
BUG_ON(!list_empty(&block->item_list));
list_del(&block->alias_list);
mempool_free(block, logfs_super(sb)->s_block_pool);
}
static void inode_free_block(struct super_block *sb, struct logfs_block *block)
{
struct inode *inode = block->inode;
logfs_inode(inode)->li_block = NULL;
__free_block(sb, block);
}
static void indirect_free_block(struct super_block *sb,
struct logfs_block *block)
{
struct page *page = block->page;
if (PagePrivate(page)) {
ClearPagePrivate(page);
page_cache_release(page);
set_page_private(page, 0);
}
__free_block(sb, block);
}
static struct logfs_block_ops inode_block_ops = {
.write_block = inode_write_block,
.free_block = inode_free_block,
.write_alias = inode_write_alias,
};
struct logfs_block_ops indirect_block_ops = {
.write_block = indirect_write_block,
.free_block = indirect_free_block,
.write_alias = indirect_write_alias,
};
struct logfs_block *__alloc_block(struct super_block *sb,
u64 ino, u64 bix, level_t level)
{
struct logfs_super *super = logfs_super(sb);
struct logfs_block *block;
block = mempool_alloc(super->s_block_pool, GFP_NOFS);
memset(block, 0, sizeof(*block));
INIT_LIST_HEAD(&block->alias_list);
INIT_LIST_HEAD(&block->item_list);
block->sb = sb;
block->ino = ino;
block->bix = bix;
block->level = level;
return block;
}
static void alloc_inode_block(struct inode *inode)
{
struct logfs_inode *li = logfs_inode(inode);
struct logfs_block *block;
if (li->li_block)
return;
block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0);
block->inode = inode;
li->li_block = block;
block->ops = &inode_block_ops;
}
void initialize_block_counters(struct page *page, struct logfs_block *block,
__be64 *array, int page_is_empty)
{
u64 ptr;
int i, start;
block->partial = 0;
block->full = 0;
start = 0;
if (page->index < first_indirect_block()) {
/* Counters are pointless on level 0 */
return;
}
if (page->index == first_indirect_block()) {
/* Skip unused pointers */
start = I0_BLOCKS;
block->full = I0_BLOCKS;
}
if (!page_is_empty) {
for (i = start; i < LOGFS_BLOCK_FACTOR; i++) {
ptr = be64_to_cpu(array[i]);
if (ptr)
block->partial++;
if (ptr & LOGFS_FULLY_POPULATED)
block->full++;
}
}
}
static void alloc_data_block(struct inode *inode, struct page *page)
{
struct logfs_block *block;
u64 bix;
level_t level;
if (PagePrivate(page))
return;
logfs_unpack_index(page->index, &bix, &level);
block = __alloc_block(inode->i_sb, inode->i_ino, bix, level);
block->page = page;
SetPagePrivate(page);
page_cache_get(page);
set_page_private(page, (unsigned long) block);
block->ops = &indirect_block_ops;
}
static void alloc_indirect_block(struct inode *inode, struct page *page,
int page_is_empty)
{
struct logfs_block *block;
__be64 *array;
if (PagePrivate(page))
return;
alloc_data_block(inode, page);
block = logfs_block(page);
array = kmap_atomic(page);
initialize_block_counters(page, block, array, page_is_empty);
kunmap_atomic(array);
}
static void block_set_pointer(struct page *page, int index, u64 ptr)
{
struct logfs_block *block = logfs_block(page);
__be64 *array;
u64 oldptr;
BUG_ON(!block);
array = kmap_atomic(page);
oldptr = be64_to_cpu(array[index]);
array[index] = cpu_to_be64(ptr);
kunmap_atomic(array);
SetPageUptodate(page);
block->full += !!(ptr & LOGFS_FULLY_POPULATED)
- !!(oldptr & LOGFS_FULLY_POPULATED);
block->partial += !!ptr - !!oldptr;
}
static u64 block_get_pointer(struct page *page, int index)
{
__be64 *block;
u64 ptr;
block = kmap_atomic(page);
ptr = be64_to_cpu(block[index]);
kunmap_atomic(block);
return ptr;
}
static int logfs_read_empty(struct page *page)
{
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
return 0;
}
static int logfs_read_direct(struct inode *inode, struct page *page)
{
struct logfs_inode *li = logfs_inode(inode);
pgoff_t index = page->index;
u64 block;
block = li->li_data[index];
if (!block)
return logfs_read_empty(page);
return logfs_segment_read(inode, page, block, index, 0);
}
static int logfs_read_loop(struct inode *inode, struct page *page,
int rw_context)
{
struct logfs_inode *li = logfs_inode(inode);
u64 bix, bofs = li->li_data[INDIRECT_INDEX];
level_t level, target_level;
int ret;
struct page *ipage;
logfs_unpack_index(page->index, &bix, &target_level);
if (!bofs)
return logfs_read_empty(page);
if (bix >= maxbix(li->li_height))
return logfs_read_empty(page);
for (level = LEVEL(li->li_height);
(__force u8)level > (__force u8)target_level;
level = SUBLEVEL(level)){
ipage = logfs_get_page(inode, bix, level, rw_context);
if (!ipage)
return -ENOMEM;
ret = logfs_segment_read(inode, ipage, bofs, bix, level);
if (ret) {
logfs_put_read_page(ipage);
return ret;
}
bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
logfs_put_page(ipage, rw_context);
if (!bofs)
return logfs_read_empty(page);
}
return logfs_segment_read(inode, page, bofs, bix, 0);
}
static int logfs_read_block(struct inode *inode, struct page *page,
int rw_context)
{
pgoff_t index = page->index;
if (index < I0_BLOCKS)
return logfs_read_direct(inode, page);
return logfs_read_loop(inode, page, rw_context);
}
static int logfs_exist_loop(struct inode *inode, u64 bix)
{
struct logfs_inode *li = logfs_inode(inode);
u64 bofs = li->li_data[INDIRECT_INDEX];
level_t level;
int ret;
struct page *ipage;
if (!bofs)
return 0;
if (bix >= maxbix(li->li_height))
return 0;
for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
ipage = logfs_get_read_page(inode, bix, level);
if (!ipage)
return -ENOMEM;
ret = logfs_segment_read(inode, ipage, bofs, bix, level);
if (ret) {
logfs_put_read_page(ipage);
return ret;
}
bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level)));
logfs_put_read_page(ipage);
if (!bofs)
return 0;
}
return 1;
}
int logfs_exist_block(struct inode *inode, u64 bix)
{
struct logfs_inode *li = logfs_inode(inode);
if (bix < I0_BLOCKS)
return !!li->li_data[bix];
return logfs_exist_loop(inode, bix);
}
static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data)
{
struct logfs_inode *li = logfs_inode(inode);
for (; bix < I0_BLOCKS; bix++)
if (data ^ (li->li_data[bix] == 0))
return bix;
return I0_BLOCKS;
}
static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data)
{
struct logfs_inode *li = logfs_inode(inode);
__be64 *rblock;
u64 increment, bofs = li->li_data[INDIRECT_INDEX];
level_t level;
int ret, slot;
struct page *page;
BUG_ON(!bofs);
for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) {
increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1));
page = logfs_get_read_page(inode, bix, level);
if (!page)
return bix;
ret = logfs_segment_read(inode, page, bofs, bix, level);
if (ret) {
logfs_put_read_page(page);
return bix;
}
slot = get_bits(bix, SUBLEVEL(level));
rblock = kmap_atomic(page);
while (slot < LOGFS_BLOCK_FACTOR) {
if (data && (rblock[slot] != 0))
break;
if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED))
break;
slot++;
bix += increment;
bix &= ~(increment - 1);
}
if (slot >= LOGFS_BLOCK_FACTOR) {
kunmap_atomic(rblock);
logfs_put_read_page(page);
return bix;
}
bofs = be64_to_cpu(rblock[slot]);
kunmap_atomic(rblock);
logfs_put_read_page(page);
if (!bofs) {
BUG_ON(data);
return bix;
}
}
return bix;
}
/**
* logfs_seek_hole - find next hole starting at a given block index
* @inode: inode to search in
* @bix: block index to start searching
*
* Returns next hole. If the file doesn't contain any further holes, the
* block address next to eof is returned instead.
*/
u64 logfs_seek_hole(struct inode *inode, u64 bix)
{
struct logfs_inode *li = logfs_inode(inode);
if (bix < I0_BLOCKS) {
bix = seek_holedata_direct(inode, bix, 0);
if (bix < I0_BLOCKS)
return bix;
}
if (!li->li_data[INDIRECT_INDEX])
return bix;
else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED)
bix = maxbix(li->li_height);
else if (bix >= maxbix(li->li_height))
return bix;
else {
bix = seek_holedata_loop(inode, bix, 0);
if (bix < maxbix(li->li_height))
return bix;
/* Should not happen anymore. But if some port writes semi-
* corrupt images (as this one used to) we might run into it.
*/
WARN_ON_ONCE(bix == maxbix(li->li_height));
}
return bix;
}
static u64 __logfs_seek_data(struct inode *inode, u64 bix)
{
struct logfs_inode *li = logfs_inode(inode);
if (bix < I0_BLOCKS) {
bix = seek_holedata_direct(inode, bix, 1);
if (bix < I0_BLOCKS)
return bix;
}
if (bix < maxbix(li->li_height)) {
if (!li->li_data[INDIRECT_INDEX])
bix = maxbix(li->li_height);
else
return seek_holedata_loop(inode, bix, 1);
}
return bix;
}
/**
* logfs_seek_data - find next data block after a given block index
* @inode: inode to search in
* @bix: block index to start searching
*
* Returns next data block. If the file doesn't contain any further data
* blocks, the last block in the file is returned instead.
*/
u64 logfs_seek_data(struct inode *inode, u64 bix)
{
struct super_block *sb = inode->i_sb;
u64 ret, end;
ret = __logfs_seek_data(inode, bix);
end = i_size_read(inode) >> sb->s_blocksize_bits;
if (ret >= end)
ret = max(bix, end);
return ret;
}
static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs)
{
return pure_ofs(li->li_data[bix]) == ofs;
}
static int __logfs_is_valid_loop(struct inode *inode, u64 bix,
u64 ofs, u64 bofs)
{
struct logfs_inode *li = logfs_inode(inode);
level_t level;
int ret;
struct page *page;
for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){
page = logfs_get_write_page(inode, bix, level);
BUG_ON(!page);
ret = logfs_segment_read(inode, page, bofs, bix, level);
if (ret) {
logfs_put_write_page(page);
return 0;
}
bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level)));
logfs_put_write_page(page);
if (!bofs)
return 0;
if (pure_ofs(bofs) == ofs)
return 1;
}
return 0;
}
static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs)
{
struct logfs_inode *li = logfs_inode(inode);
u64 bofs = li->li_data[INDIRECT_INDEX];
if (!bofs)
return 0;
if (bix >= maxbix(li->li_height))
return 0;
if (pure_ofs(bofs) == ofs)
return 1;
return __logfs_is_valid_loop(inode, bix, ofs, bofs);
}
static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs)
{
struct logfs_inode *li = logfs_inode(inode);
if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1)
return 0;
if (bix < I0_BLOCKS)
return logfs_is_valid_direct(li, bix, ofs);
return logfs_is_valid_loop(inode, bix, ofs);
}
/**
* logfs_is_valid_block - check whether this block is still valid
*
* @sb: superblock
* @ofs: block physical offset
* @ino: block inode number
* @bix: block index
* @gc_level: block level
*
* Returns 0 if the block is invalid, 1 if it is valid and 2 if it will
* become invalid once the journal is written.
*/
int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix,
gc_level_t gc_level)
{
struct logfs_super *super = logfs_super(sb);
struct inode *inode;
int ret, cookie;
/* Umount closes a segment with free blocks remaining. Those
* blocks are by definition invalid. */
if (ino == -1)
return 0;
LOGFS_BUG_ON((u64)(u_long)ino != ino, sb);
inode = logfs_safe_iget(sb, ino, &cookie);
if (IS_ERR(inode))
goto invalid;
ret = __logfs_is_valid_block(inode, bix, ofs);
logfs_safe_iput(inode, cookie);
if (ret)
return ret;
invalid:
/* Block is nominally invalid, but may still sit in the shadow tree,
* waiting for a journal commit.
*/
if (btree_lookup64(&super->s_shadow_tree.old, ofs))
return 2;
return 0;
}
int logfs_readpage_nolock(struct page *page)
{
struct inode *inode = page->mapping->host;
int ret = -EIO;
ret = logfs_read_block(inode, page, READ);
if (ret) {
ClearPageUptodate(page);
SetPageError(page);
} else {
SetPageUptodate(page);
ClearPageError(page);
}
flush_dcache_page(page);
return ret;
}
static int logfs_reserve_bytes(struct inode *inode, int bytes)
{
struct logfs_super *super = logfs_super(inode->i_sb);
u64 available = super->s_free_bytes + super->s_dirty_free_bytes
- super->s_dirty_used_bytes - super->s_dirty_pages;
if (!bytes)
return 0;
if (available < bytes)
return -ENOSPC;
if (available < bytes + super->s_root_reserve &&
!capable(CAP_SYS_RESOURCE))
return -ENOSPC;
return 0;
}
int get_page_reserve(struct inode *inode, struct page *page)
{
struct logfs_super *super = logfs_super(inode->i_sb);
struct logfs_block *block = logfs_block(page);
int ret;
if (block && block->reserved_bytes)
return 0;
logfs_get_wblocks(inode->i_sb, page, WF_LOCK);
while ((ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE)) &&
!list_empty(&super->s_writeback_list)) {
block = list_entry(super->s_writeback_list.next,
struct logfs_block, alias_list);
block->ops->write_block(block);
}
if (!ret) {
alloc_data_block(inode, page);
block = logfs_block(page);
block->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE;
super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE;
list_move_tail(&block->alias_list, &super->s_writeback_list);
}
logfs_put_wblocks(inode->i_sb, page, WF_LOCK);
return ret;
}
/*
* We are protected by write lock. Push victims up to superblock level
* and release transaction when appropriate.
*/
/* FIXME: This is currently called from the wrong spots. */
static void logfs_handle_transaction(struct inode *inode,
struct logfs_transaction *ta)
{
struct logfs_super *super = logfs_super(inode->i_sb);
if (!ta)
return;
logfs_inode(inode)->li_block->ta = NULL;
if (inode->i_ino != LOGFS_INO_MASTER) {
BUG(); /* FIXME: Yes, this needs more thought */
/* just remember the transaction until inode is written */
//BUG_ON(logfs_inode(inode)->li_transaction);
//logfs_inode(inode)->li_transaction = ta;
return;
}
switch (ta->state) {
case CREATE_1: /* fall through */
case UNLINK_1:
BUG_ON(super->s_victim_ino);
super->s_victim_ino = ta->ino;
break;
case CREATE_2: /* fall through */
case UNLINK_2:
BUG_ON(super->s_victim_ino != ta->ino);
super->s_victim_ino = 0;
/* transaction ends here - free it */
kfree(ta);
break;
case CROSS_RENAME_1:
BUG_ON(super->s_rename_dir);
BUG_ON(super->s_rename_pos);
super->s_rename_dir = ta->dir;
super->s_rename_pos = ta->pos;
break;
case CROSS_RENAME_2:
BUG_ON(super->s_rename_dir != ta->dir);
BUG_ON(super->s_rename_pos != ta->pos);
super->s_rename_dir = 0;
super->s_rename_pos = 0;
kfree(ta);
break;
case TARGET_RENAME_1:
BUG_ON(super->s_rename_dir);
BUG_ON(super->s_rename_pos);
BUG_ON(super->s_victim_ino);
super->s_rename_dir = ta->dir;
super->s_rename_pos = ta->pos;
super->s_victim_ino = ta->ino;
break;
case TARGET_RENAME_2:
BUG_ON(super->s_rename_dir != ta->dir);
BUG_ON(super->s_rename_pos != ta->pos);
BUG_ON(super->s_victim_ino != ta->ino);
super->s_rename_dir = 0;
super->s_rename_pos = 0;
break;
case TARGET_RENAME_3:
BUG_ON(super->s_rename_dir);
BUG_ON(super->s_rename_pos);
BUG_ON(super->s_victim_ino != ta->ino);
super->s_victim_ino = 0;
kfree(ta);
break;
default:
BUG();
}
}
/*
* Not strictly a reservation, but rather a check that we still have enough
* space to satisfy the write.
*/
static int logfs_reserve_blocks(struct inode *inode, int blocks)
{
return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE);
}
struct write_control {
u64 ofs;
long flags;
};
static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix,
level_t level, u64 old_ofs)
{
struct logfs_super *super = logfs_super(inode->i_sb);
struct logfs_shadow *shadow;
shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS);
memset(shadow, 0, sizeof(*shadow));
shadow->ino = inode->i_ino;
shadow->bix = bix;
shadow->gc_level = expand_level(inode->i_ino, level);
shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED;
return shadow;
}
static void free_shadow(struct inode *inode, struct logfs_shadow *shadow)
{
struct logfs_super *super = logfs_super(inode->i_sb);
mempool_free(shadow, super->s_shadow_pool);
}
static void mark_segment(struct shadow_tree *tree, u32 segno)
{
int err;
if (!btree_lookup32(&tree->segment_map, segno)) {
err = btree_insert32(&tree->segment_map, segno, (void *)1,
GFP_NOFS);
BUG_ON(err);
tree->no_shadowed_segments++;
}
}
/**
* fill_shadow_tree - Propagate shadow tree changes due to a write
* @inode: Inode owning the page
* @page: Struct page that was written
* @shadow: Shadow for the current write
*
* Writes in logfs can result in two semi-valid objects. The old object
* is still valid as long as it can be reached by following pointers on
* the medium. Only when writes propagate all the way up to the journal
* has the new object safely replaced the old one.
*
* To handle this problem, a struct logfs_shadow is used to represent
* every single write. It is attached to the indirect block, which is
* marked dirty. When the indirect block is written, its shadows are
* handed up to the next indirect block (or inode). Untimately they
* will reach the master inode and be freed upon journal commit.
*
* This function handles a single step in the propagation. It adds the
* shadow for the current write to the tree, along with any shadows in
* the page's tree, in case it was an indirect block. If a page is
* written, the inode parameter is left NULL, if an inode is written,
* the page parameter is left NULL.
*/
static void fill_shadow_tree(struct inode *inode, struct page *page,
struct logfs_shadow *shadow)
{
struct logfs_super *super = logfs_super(inode->i_sb);
struct logfs_block *block = logfs_block(page);
struct shadow_tree *tree = &super->s_shadow_tree;
if (PagePrivate(page)) {
if (block->alias_map)
super->s_no_object_aliases -= bitmap_weight(
block->alias_map, LOGFS_BLOCK_FACTOR);
logfs_handle_transaction(inode, block->ta);
block->ops->free_block(inode->i_sb, block);
}
if (shadow) {
if (shadow->old_ofs)
btree_insert64(&tree->old, shadow->old_ofs, shadow,
GFP_NOFS);
else
btree_insert64(&tree->new, shadow->new_ofs, shadow,
GFP_NOFS);
super->s_dirty_used_bytes += shadow->new_len;
super->s_dirty_free_bytes += shadow->old_len;
mark_segment(tree, shadow->old_ofs >> super->s_segshift);
mark_segment(tree, shadow->new_ofs >> super->s_segshift);
}
}
static void logfs_set_alias(struct super_block *sb, struct logfs_block *block,
long child_no)
{
struct logfs_super *super = logfs_super(sb);
if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) {
/* Aliases in the master inode are pointless. */
return;
}
if (!test_bit(child_no, block->alias_map)) {
set_bit(child_no, block->alias_map);
super->s_no_object_aliases++;
}
list_move_tail(&block->alias_list, &super->s_object_alias);
}
/*
* Object aliases can and often do change the size and occupied space of a
* file. So not only do we have to change the pointers, we also have to
* change inode->i_size and li->li_used_bytes. Which is done by setting
* another two object aliases for the inode itself.
*/
static void set_iused(struct inode *inode, struct logfs_shadow *shadow)
{
struct logfs_inode *li = logfs_inode(inode);
if (shadow->new_len == shadow->old_len)
return;
alloc_inode_block(inode);
li->li_used_bytes += shadow->new_len - shadow->old_len;
__logfs_set_blocks(inode);
logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS);
logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS);
}
static int logfs_write_i0(struct inode *inode, struct page *page,
struct write_control *wc)
{
struct logfs_shadow *shadow;
u64 bix;
level_t level;
int full, err = 0;
logfs_unpack_index(page->index, &bix, &level);
if (wc->ofs == 0)
if (logfs_reserve_blocks(inode, 1))
return -ENOSPC;
shadow = alloc_shadow(inode, bix, level, wc->ofs);
if (wc->flags & WF_WRITE)
err = logfs_segment_write(inode, page, shadow);
if (wc->flags & WF_DELETE)
logfs_segment_delete(inode, shadow);
if (err) {
free_shadow(inode, shadow);
return err;
}
set_iused(inode, shadow);
full = 1;
if (level != 0) {
alloc_indirect_block(inode, page, 0);
full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR;
}
fill_shadow_tree(inode, page, shadow);
wc->ofs = shadow->new_ofs;
if (wc->ofs && full)
wc->ofs |= LOGFS_FULLY_POPULATED;
return 0;
}
static int logfs_write_direct(struct inode *inode, struct page *page,
long flags)
{
struct logfs_inode *li = logfs_inode(inode);
struct write_control wc = {
.ofs = li->li_data[page->index],
.flags = flags,
};
int err;
alloc_inode_block(inode);
err = logfs_write_i0(inode, page, &wc);
if (err)
return err;
li->li_data[page->index] = wc.ofs;
logfs_set_alias(inode->i_sb, li->li_block,
page->index + INODE_POINTER_OFS);
return 0;
}
static int ptr_change(u64 ofs, struct page *page)
{
struct logfs_block *block = logfs_block(page);
int empty0, empty1, full0, full1;
empty0 = ofs == 0;
empty1 = block->partial == 0;
if (empty0 != empty1)
return 1;
/* The !! is necessary to shrink result to int */
full0 = !!(ofs & LOGFS_FULLY_POPULATED);
full1 = block->full == LOGFS_BLOCK_FACTOR;
if (full0 != full1)
return 1;
return 0;
}
static int __logfs_write_rec(struct inode *inode, struct page *page,
struct write_control *this_wc,
pgoff_t bix, level_t target_level, level_t level)
{
int ret, page_empty = 0;
int child_no = get_bits(bix, SUBLEVEL(level));
struct page *ipage;
struct write_control child_wc = {
.flags = this_wc->flags,
};
ipage = logfs_get_write_page(inode, bix, level);
if (!ipage)
return -ENOMEM;
if (this_wc->ofs) {
ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
if (ret)
goto out;
} else if (!PageUptodate(ipage)) {
page_empty = 1;
logfs_read_empty(ipage);
}
child_wc.ofs = block_get_pointer(ipage, child_no);
if ((__force u8)level-1 > (__force u8)target_level)
ret = __logfs_write_rec(inode, page, &child_wc, bix,
target_level, SUBLEVEL(level));
else
ret = logfs_write_i0(inode, page, &child_wc);
if (ret)
goto out;
alloc_indirect_block(inode, ipage, page_empty);
block_set_pointer(ipage, child_no, child_wc.ofs);
/* FIXME: first condition seems superfluous */
if (child_wc.ofs || logfs_block(ipage)->partial)
this_wc->flags |= WF_WRITE;
/* the condition on this_wc->ofs ensures that we won't consume extra
* space for indirect blocks in the future, which we cannot reserve */
if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage))
ret = logfs_write_i0(inode, ipage, this_wc);
else
logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no);
out:
logfs_put_write_page(ipage);
return ret;
}
static int logfs_write_rec(struct inode *inode, struct page *page,
pgoff_t bix, level_t target_level, long flags)
{
struct logfs_inode *li = logfs_inode(inode);
struct write_control wc = {
.ofs = li->li_data[INDIRECT_INDEX],
.flags = flags,
};
int ret;
alloc_inode_block(inode);
if (li->li_height > (__force u8)target_level)
ret = __logfs_write_rec(inode, page, &wc, bix, target_level,
LEVEL(li->li_height));
else
ret = logfs_write_i0(inode, page, &wc);
if (ret)
return ret;
if (li->li_data[INDIRECT_INDEX] != wc.ofs) {
li->li_data[INDIRECT_INDEX] = wc.ofs;
logfs_set_alias(inode->i_sb, li->li_block,
INDIRECT_INDEX + INODE_POINTER_OFS);
}
return ret;
}
void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta)
{
alloc_inode_block(inode);
logfs_inode(inode)->li_block->ta = ta;
}
void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta)
{
struct logfs_block *block = logfs_inode(inode)->li_block;
if (block && block->ta)
block->ta = NULL;
}
static int grow_inode(struct inode *inode, u64 bix, level_t level)
{
struct logfs_inode *li = logfs_inode(inode);
u8 height = (__force u8)level;
struct page *page;
struct write_control wc = {
.flags = WF_WRITE,
};
int err;
BUG_ON(height > 5 || li->li_height > 5);
while (height > li->li_height || bix >= maxbix(li->li_height)) {
page = logfs_get_write_page(inode, I0_BLOCKS + 1,
LEVEL(li->li_height + 1));
if (!page)
return -ENOMEM;
logfs_read_empty(page);
alloc_indirect_block(inode, page, 1);
block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]);
err = logfs_write_i0(inode, page, &wc);
logfs_put_write_page(page);
if (err)
return err;
li->li_data[INDIRECT_INDEX] = wc.ofs;
wc.ofs = 0;
li->li_height++;
logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS);
}
return 0;
}
static int __logfs_write_buf(struct inode *inode, struct page *page, long flags)
{
struct logfs_super *super = logfs_super(inode->i_sb);
pgoff_t index = page->index;
u64 bix;
level_t level;
int err;
flags |= WF_WRITE | WF_DELETE;
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
logfs_unpack_index(index, &bix, &level);
if (logfs_block(page) && logfs_block(page)->reserved_bytes)
super->s_dirty_pages -= logfs_block(page)->reserved_bytes;
if (index < I0_BLOCKS)
return logfs_write_direct(inode, page, flags);
bix = adjust_bix(bix, level);
err = grow_inode(inode, bix, level);
if (err)
return err;
return logfs_write_rec(inode, page, bix, level, flags);
}
int logfs_write_buf(struct inode *inode, struct page *page, long flags)
{
struct super_block *sb = inode->i_sb;
int ret;
logfs_get_wblocks(sb, page, flags & WF_LOCK);
ret = __logfs_write_buf(inode, page, flags);
logfs_put_wblocks(sb, page, flags & WF_LOCK);
return ret;
}
static int __logfs_delete(struct inode *inode, struct page *page)
{
long flags = WF_DELETE;
int err;
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
if (page->index < I0_BLOCKS)
return logfs_write_direct(inode, page, flags);
err = grow_inode(inode, page->index, 0);
if (err)
return err;
return logfs_write_rec(inode, page, page->index, 0, flags);
}
int logfs_delete(struct inode *inode, pgoff_t index,
struct shadow_tree *shadow_tree)
{
struct super_block *sb = inode->i_sb;
struct page *page;
int ret;
page = logfs_get_read_page(inode, index, 0);
if (!page)
return -ENOMEM;
logfs_get_wblocks(sb, page, 1);
ret = __logfs_delete(inode, page);
logfs_put_wblocks(sb, page, 1);
logfs_put_read_page(page);
return ret;
}
int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs,
gc_level_t gc_level, long flags)
{
level_t level = shrink_level(gc_level);
struct page *page;
int err;
page = logfs_get_write_page(inode, bix, level);
if (!page)
return -ENOMEM;
err = logfs_segment_read(inode, page, ofs, bix, level);
if (!err) {
if (level != 0)
alloc_indirect_block(inode, page, 0);
err = logfs_write_buf(inode, page, flags);
if (!err && shrink_level(gc_level) == 0) {
/* Rewrite cannot mark the inode dirty but has to
* write it immediately.
* Q: Can't we just create an alias for the inode
* instead? And if not, why not?
*/
if (inode->i_ino == LOGFS_INO_MASTER)
logfs_write_anchor(inode->i_sb);
else {
err = __logfs_write_inode(inode, page, flags);
}
}
}
logfs_put_write_page(page);
return err;
}
static int truncate_data_block(struct inode *inode, struct page *page,
u64 ofs, struct logfs_shadow *shadow, u64 size)
{
loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits;
u64 bix;
level_t level;
int err;
/* Does truncation happen within this page? */
if (size <= pageofs || size - pageofs >= PAGE_SIZE)
return 0;
logfs_unpack_index(page->index, &bix, &level);
BUG_ON(level != 0);
err = logfs_segment_read(inode, page, ofs, bix, level);
if (err)
return err;
zero_user_segment(page, size - pageofs, PAGE_CACHE_SIZE);
return logfs_segment_write(inode, page, shadow);
}
static int logfs_truncate_i0(struct inode *inode, struct page *page,
struct write_control *wc, u64 size)
{
struct logfs_shadow *shadow;
u64 bix;
level_t level;
int err = 0;
logfs_unpack_index(page->index, &bix, &level);
BUG_ON(level != 0);
shadow = alloc_shadow(inode, bix, level, wc->ofs);
err = truncate_data_block(inode, page, wc->ofs, shadow, size);
if (err) {
free_shadow(inode, shadow);
return err;
}
logfs_segment_delete(inode, shadow);
set_iused(inode, shadow);
fill_shadow_tree(inode, page, shadow);
wc->ofs = shadow->new_ofs;
return 0;
}
static int logfs_truncate_direct(struct inode *inode, u64 size)
{
struct logfs_inode *li = logfs_inode(inode);
struct write_control wc;
struct page *page;
int e;
int err;
alloc_inode_block(inode);
for (e = I0_BLOCKS - 1; e >= 0; e--) {
if (size > (e+1) * LOGFS_BLOCKSIZE)
break;
wc.ofs = li->li_data[e];
if (!wc.ofs)
continue;
page = logfs_get_write_page(inode, e, 0);
if (!page)
return -ENOMEM;
err = logfs_segment_read(inode, page, wc.ofs, e, 0);
if (err) {
logfs_put_write_page(page);
return err;
}
err = logfs_truncate_i0(inode, page, &wc, size);
logfs_put_write_page(page);
if (err)
return err;
li->li_data[e] = wc.ofs;
}
return 0;
}
/* FIXME: these need to become per-sb once we support different blocksizes */
static u64 __logfs_step[] = {
1,
I1_BLOCKS,
I2_BLOCKS,
I3_BLOCKS,
};
static u64 __logfs_start_index[] = {
I0_BLOCKS,
I1_BLOCKS,
I2_BLOCKS,
I3_BLOCKS
};
static inline u64 logfs_step(level_t level)
{
return __logfs_step[(__force u8)level];
}
static inline u64 logfs_factor(u8 level)
{
return __logfs_step[level] * LOGFS_BLOCKSIZE;
}
static inline u64 logfs_start_index(level_t level)
{
return __logfs_start_index[(__force u8)level];
}
static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level)
{
logfs_unpack_index(index, bix, level);
if (*bix <= logfs_start_index(SUBLEVEL(*level)))
*bix = 0;
}
static int __logfs_truncate_rec(struct inode *inode, struct page *ipage,
struct write_control *this_wc, u64 size)
{
int truncate_happened = 0;
int e, err = 0;
u64 bix, child_bix, next_bix;
level_t level;
struct page *page;
struct write_control child_wc = { /* FIXME: flags */ };
logfs_unpack_raw_index(ipage->index, &bix, &level);
err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level);
if (err)
return err;
for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) {
child_bix = bix + e * logfs_step(SUBLEVEL(level));
next_bix = child_bix + logfs_step(SUBLEVEL(level));
if (size > next_bix * LOGFS_BLOCKSIZE)
break;
child_wc.ofs = pure_ofs(block_get_pointer(ipage, e));
if (!child_wc.ofs)
continue;
page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level));
if (!page)
return -ENOMEM;
if ((__force u8)level > 1)
err = __logfs_truncate_rec(inode, page, &child_wc, size);
else
err = logfs_truncate_i0(inode, page, &child_wc, size);
logfs_put_write_page(page);
if (err)
return err;
truncate_happened = 1;
alloc_indirect_block(inode, ipage, 0);
block_set_pointer(ipage, e, child_wc.ofs);
}
if (!truncate_happened) {
printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size);
return 0;
}
this_wc->flags = WF_DELETE;
if (logfs_block(ipage)->partial)
this_wc->flags |= WF_WRITE;
return logfs_write_i0(inode, ipage, this_wc);
}
static int logfs_truncate_rec(struct inode *inode, u64 size)
{
struct logfs_inode *li = logfs_inode(inode);
struct write_control wc = {
.ofs = li->li_data[INDIRECT_INDEX],
};
struct page *page;
int err;
alloc_inode_block(inode);
if (!wc.ofs)
return 0;
page = logfs_get_write_page(inode, 0, LEVEL(li->li_height));
if (!page)
return -ENOMEM;
err = __logfs_truncate_rec(inode, page, &wc, size);
logfs_put_write_page(page);
if (err)
return err;
if (li->li_data[INDIRECT_INDEX] != wc.ofs)
li->li_data[INDIRECT_INDEX] = wc.ofs;
return 0;
}
static int __logfs_truncate(struct inode *inode, u64 size)
{
int ret;
if (size >= logfs_factor(logfs_inode(inode)->li_height))
return 0;
ret = logfs_truncate_rec(inode, size);
if (ret)
return ret;
return logfs_truncate_direct(inode, size);
}
/*
* Truncate, by changing the segment file, can consume a fair amount
* of resources. So back off from time to time and do some GC.
* 8 or 2048 blocks should be well within safety limits even if
* every single block resided in a different segment.
*/
#define TRUNCATE_STEP (8 * 1024 * 1024)
int logfs_truncate(struct inode *inode, u64 target)
{
struct super_block *sb = inode->i_sb;
u64 size = i_size_read(inode);
int err = 0;
size = ALIGN(size, TRUNCATE_STEP);
while (size > target) {
if (size > TRUNCATE_STEP)
size -= TRUNCATE_STEP;
else
size = 0;
if (size < target)
size = target;
logfs_get_wblocks(sb, NULL, 1);
err = __logfs_truncate(inode, size);
if (!err)
err = __logfs_write_inode(inode, NULL, 0);
logfs_put_wblocks(sb, NULL, 1);
}
if (!err) {
err = inode_newsize_ok(inode, target);
if (err)
goto out;
truncate_setsize(inode, target);
}
out:
/* I don't trust error recovery yet. */
WARN_ON(err);
return err;
}
static void move_page_to_inode(struct inode *inode, struct page *page)
{
struct logfs_inode *li = logfs_inode(inode);
struct logfs_block *block = logfs_block(page);
if (!block)
return;
log_blockmove("move_page_to_inode(%llx, %llx, %x)\n",
block->ino, block->bix, block->level);
BUG_ON(li->li_block);
block->ops = &inode_block_ops;
block->inode = inode;
li->li_block = block;
block->page = NULL;
if (PagePrivate(page)) {
ClearPagePrivate(page);
page_cache_release(page);
set_page_private(page, 0);
}
}
static void move_inode_to_page(struct page *page, struct inode *inode)
{
struct logfs_inode *li = logfs_inode(inode);
struct logfs_block *block = li->li_block;
if (!block)
return;
log_blockmove("move_inode_to_page(%llx, %llx, %x)\n",
block->ino, block->bix, block->level);
BUG_ON(PagePrivate(page));
block->ops = &indirect_block_ops;
block->page = page;
if (!PagePrivate(page)) {
SetPagePrivate(page);
page_cache_get(page);
set_page_private(page, (unsigned long) block);
}
block->inode = NULL;
li->li_block = NULL;
}
int logfs_read_inode(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct logfs_super *super = logfs_super(sb);
struct inode *master_inode = super->s_master_inode;
struct page *page;
struct logfs_disk_inode *di;
u64 ino = inode->i_ino;
if (ino << sb->s_blocksize_bits > i_size_read(master_inode))
return -ENODATA;
if (!logfs_exist_block(master_inode, ino))
return -ENODATA;
page = read_cache_page(master_inode->i_mapping, ino,
(filler_t *)logfs_readpage, NULL);
if (IS_ERR(page))
return PTR_ERR(page);
di = kmap_atomic(page);
logfs_disk_to_inode(di, inode);
kunmap_atomic(di);
move_page_to_inode(inode, page);
page_cache_release(page);
return 0;
}
/* Caller must logfs_put_write_page(page); */
static struct page *inode_to_page(struct inode *inode)
{
struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode;
struct logfs_disk_inode *di;
struct page *page;
BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
page = logfs_get_write_page(master_inode, inode->i_ino, 0);
if (!page)
return NULL;
di = kmap_atomic(page);
logfs_inode_to_disk(inode, di);
kunmap_atomic(di);
move_inode_to_page(page, inode);
return page;
}
static int do_write_inode(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct inode *master_inode = logfs_super(sb)->s_master_inode;
loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits;
struct page *page;
int err;
BUG_ON(inode->i_ino == LOGFS_INO_MASTER);
/* FIXME: lock inode */
if (i_size_read(master_inode) < size)
i_size_write(master_inode, size);
/* TODO: Tell vfs this inode is clean now */
page = inode_to_page(inode);
if (!page)
return -ENOMEM;
/* FIXME: transaction is part of logfs_block now. Is that enough? */
err = logfs_write_buf(master_inode, page, 0);
if (err)
move_page_to_inode(inode, page);
logfs_put_write_page(page);
return err;
}
static void logfs_mod_segment_entry(struct super_block *sb, u32 segno,
int write,
void (*change_se)(struct logfs_segment_entry *, long),
long arg)
{
struct logfs_super *super = logfs_super(sb);
struct inode *inode;
struct page *page;
struct logfs_segment_entry *se;
pgoff_t page_no;
int child_no;
page_no = segno >> (sb->s_blocksize_bits - 3);
child_no = segno & ((sb->s_blocksize >> 3) - 1);
inode = super->s_segfile_inode;
page = logfs_get_write_page(inode, page_no, 0);
BUG_ON(!page); /* FIXME: We need some reserve page for this case */
if (!PageUptodate(page))
logfs_read_block(inode, page, WRITE);
if (write)
alloc_indirect_block(inode, page, 0);
se = kmap_atomic(page);
change_se(se + child_no, arg);
if (write) {
logfs_set_alias(sb, logfs_block(page), child_no);
BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize);
}
kunmap_atomic(se);
logfs_put_write_page(page);
}
static void __get_segment_entry(struct logfs_segment_entry *se, long _target)
{
struct logfs_segment_entry *target = (void *)_target;
*target = *se;
}
void logfs_get_segment_entry(struct super_block *sb, u32 segno,
struct logfs_segment_entry *se)
{
logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se);
}
static void __set_segment_used(struct logfs_segment_entry *se, long increment)
{
u32 valid;
valid = be32_to_cpu(se->valid);
valid += increment;
se->valid = cpu_to_be32(valid);
}
void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment)
{
struct logfs_super *super = logfs_super(sb);
u32 segno = ofs >> super->s_segshift;
if (!increment)
return;
logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment);
}
static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level)
{
se->ec_level = cpu_to_be32(ec_level);
}
void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec,
gc_level_t gc_level)
{
u32 ec_level = ec << 4 | (__force u8)gc_level;
logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level);
}
static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore)
{
se->valid = cpu_to_be32(RESERVED);
}
void logfs_set_segment_reserved(struct super_block *sb, u32 segno)
{
logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0);
}
static void __set_segment_unreserved(struct logfs_segment_entry *se,
long ec_level)
{
se->valid = 0;
se->ec_level = cpu_to_be32(ec_level);
}
void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec)
{
u32 ec_level = ec << 4;
logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved,
ec_level);
}
int __logfs_write_inode(struct inode *inode, struct page *page, long flags)
{
struct super_block *sb = inode->i_sb;
int ret;
logfs_get_wblocks(sb, page, flags & WF_LOCK);
ret = do_write_inode(inode);
logfs_put_wblocks(sb, page, flags & WF_LOCK);
return ret;
}
static int do_delete_inode(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct inode *master_inode = logfs_super(sb)->s_master_inode;
struct page *page;
int ret;
page = logfs_get_write_page(master_inode, inode->i_ino, 0);
if (!page)
return -ENOMEM;
move_inode_to_page(page, inode);
logfs_get_wblocks(sb, page, 1);
ret = __logfs_delete(master_inode, page);
logfs_put_wblocks(sb, page, 1);
logfs_put_write_page(page);
return ret;
}
/*
* ZOMBIE inodes have already been deleted before and should remain dead,
* if it weren't for valid checking. No need to kill them again here.
*/
void logfs_evict_inode(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct logfs_inode *li = logfs_inode(inode);
struct logfs_block *block = li->li_block;
struct page *page;
if (!inode->i_nlink) {
if (!(li->li_flags & LOGFS_IF_ZOMBIE)) {
li->li_flags |= LOGFS_IF_ZOMBIE;
if (i_size_read(inode) > 0)
logfs_truncate(inode, 0);
do_delete_inode(inode);
}
}
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
/* Cheaper version of write_inode. All changes are concealed in
* aliases, which are moved back. No write to the medium happens.
*/
/* Only deleted files may be dirty at this point */
BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink);
if (!block)
return;
if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) {
block->ops->free_block(inode->i_sb, block);
return;
}
page = inode_to_page(inode);
BUG_ON(!page); /* FIXME: Use emergency page */
logfs_put_write_page(page);
}
void btree_write_block(struct logfs_block *block)
{
struct inode *inode;
struct page *page;
int err, cookie;
inode = logfs_safe_iget(block->sb, block->ino, &cookie);
page = logfs_get_write_page(inode, block->bix, block->level);
err = logfs_readpage_nolock(page);
BUG_ON(err);
BUG_ON(!PagePrivate(page));
BUG_ON(logfs_block(page) != block);
err = __logfs_write_buf(inode, page, 0);
BUG_ON(err);
BUG_ON(PagePrivate(page) || page->private);
logfs_put_write_page(page);
logfs_safe_iput(inode, cookie);
}
/**
* logfs_inode_write - write inode or dentry objects
*
* @inode: parent inode (ifile or directory)
* @buf: object to write (inode or dentry)
* @count: object size
* @bix: block index
* @flags: write flags
* @shadow_tree: shadow below this inode
*
* FIXME: All caller of this put a 200-300 byte variable on the stack,
* only to call here and do a memcpy from that stack variable. A good
* example of wasted performance and stack space.
*/
int logfs_inode_write(struct inode *inode, const void *buf, size_t count,
loff_t bix, long flags, struct shadow_tree *shadow_tree)
{
loff_t pos = bix << inode->i_sb->s_blocksize_bits;
int err;
struct page *page;
void *pagebuf;
BUG_ON(pos & (LOGFS_BLOCKSIZE-1));
BUG_ON(count > LOGFS_BLOCKSIZE);
page = logfs_get_write_page(inode, bix, 0);
if (!page)
return -ENOMEM;
pagebuf = kmap_atomic(page);
memcpy(pagebuf, buf, count);
flush_dcache_page(page);
kunmap_atomic(pagebuf);
if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE)
i_size_write(inode, pos + LOGFS_BLOCKSIZE);
err = logfs_write_buf(inode, page, flags);
logfs_put_write_page(page);
return err;
}
int logfs_open_segfile(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
struct inode *inode;
inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE);
if (IS_ERR(inode))
return PTR_ERR(inode);
super->s_segfile_inode = inode;
return 0;
}
int logfs_init_rw(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
int min_fill = 3 * super->s_no_blocks;
INIT_LIST_HEAD(&super->s_object_alias);
INIT_LIST_HEAD(&super->s_writeback_list);
mutex_init(&super->s_write_mutex);
super->s_block_pool = mempool_create_kmalloc_pool(min_fill,
sizeof(struct logfs_block));
super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill,
sizeof(struct logfs_shadow));
return 0;
}
void logfs_cleanup_rw(struct super_block *sb)
{
struct logfs_super *super = logfs_super(sb);
logfs_mempool_destroy(super->s_block_pool);
logfs_mempool_destroy(super->s_shadow_pool);
}