linux/fs/logfs/readwrite.c
Linus Torvalds 89a897fbd8 Pull request from git://github.com/prasad-joshi/logfs_upstream.git
There are few important bug fixes for LogFS
 
 9f0bbd8 logfs: query block device for number of pages to send with bio
 	This BUG was found when LogFS was used on KVM. The patch fixes
 	the problem by asking for underlaying block device the number
 	of pages to send with each BIO.
 
 41b93bc logfs: maintain the ordering of meta-inode destruction
 	LogFS maintains file system meta-data in special inodes. These
 	inodes are releated to each other, therefore they must be
 	destroyed in a proper order.
 
 ddb24bb logfs: create a pagecache page if it is not present
 
 cd8bfa9 logfs: initialize the number of iovecs in bio
 	LogFS used to panic when it was created on an encrypted LVM
 	volume. The patch fixes the problem by properly initializing
 	the BIO.
 
 d2dcd90 logfs: destroy the reserved inodes while unmounting
 
 Diffstat:
  fs/logfs/dev_bdev.c  |   15 ++++++++-------
  fs/logfs/inode.c     |   18 +-----------------
  fs/logfs/journal.c   |    2 +-
  fs/logfs/readwrite.c |    1 +
  fs/logfs/segment.c   |    2 +-
  5 files changed, 12 insertions(+), 26 deletions(-)
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Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream

Pull LogFS bugfixes from Prasad Joshi:

 - "logfs: query block device for number of pages to send with bio"

	This BUG was found when LogFS was used on KVM. The patch fixes
	the problem by asking for underlaying block device the number
	of pages to send with each BIO.

 - "logfs: maintain the ordering of meta-inode destruction"

	LogFS maintains file system meta-data in special inodes. These
	inodes are releated to each other, therefore they must be
	destroyed in a proper order.

 - "logfs: initialize the number of iovecs in bio"

	LogFS used to panic when it was created on an encrypted LVM
	volume. The patch fixes the problem by properly initializing
	the BIO.

Plus a couple more:
 - logfs: create a pagecache page if it is not present
 - logfs: destroy the reserved inodes while unmounting

* tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream:
  logfs: query block device for number of pages to send with bio
  logfs: maintain the ordering of meta-inode destruction
  logfs: create a pagecache page if it is not present
  logfs: initialize the number of iovecs in bio
  logfs: destroy the reserved inodes while unmounting
2012-08-26 10:14:11 -07:00

2293 lines
56 KiB
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);
inode->i_uid = be32_to_cpu(di->di_uid);
inode->i_gid = 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(inode->i_uid);
di->di_gid = cpu_to_be32(inode->i_gid);
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
* @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 = vmtruncate(inode, target);
/* 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(&inode->i_data, 0);
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)
* @n: object size
* @_pos: object number (file position in blocks/objects)
* @flags: write flags
* @lock: 0 if write lock is already taken, 1 otherwise
* @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);
}