- 根目录:
- fs
- f2fs
- data.c
/*
* fs/f2fs/data.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/fs.h>
#include <linux/f2fs_fs.h>
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/aio.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/prefetch.h>
#include "f2fs.h"
#include "node.h"
#include "segment.h"
#include <trace/events/f2fs.h>
/*
* Lock ordering for the change of data block address:
* ->data_page
* ->node_page
* update block addresses in the node page
*/
static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
{
struct f2fs_node *rn;
__le32 *addr_array;
struct page *node_page = dn->node_page;
unsigned int ofs_in_node = dn->ofs_in_node;
wait_on_page_writeback(node_page);
rn = (struct f2fs_node *)page_address(node_page);
/* Get physical address of data block */
addr_array = blkaddr_in_node(rn);
addr_array[ofs_in_node] = cpu_to_le32(new_addr);
set_page_dirty(node_page);
}
int reserve_new_block(struct dnode_of_data *dn)
{
struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
return -EPERM;
if (!inc_valid_block_count(sbi, dn->inode, 1))
return -ENOSPC;
trace_f2fs_reserve_new_block(dn->inode, dn->nid, dn->ofs_in_node);
__set_data_blkaddr(dn, NEW_ADDR);
dn->data_blkaddr = NEW_ADDR;
sync_inode_page(dn);
return 0;
}
static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
struct buffer_head *bh_result)
{
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
pgoff_t start_fofs, end_fofs;
block_t start_blkaddr;
read_lock(&fi->ext.ext_lock);
if (fi->ext.len == 0) {
read_unlock(&fi->ext.ext_lock);
return 0;
}
sbi->total_hit_ext++;
start_fofs = fi->ext.fofs;
end_fofs = fi->ext.fofs + fi->ext.len - 1;
start_blkaddr = fi->ext.blk_addr;
if (pgofs >= start_fofs && pgofs <= end_fofs) {
unsigned int blkbits = inode->i_sb->s_blocksize_bits;
size_t count;
clear_buffer_new(bh_result);
map_bh(bh_result, inode->i_sb,
start_blkaddr + pgofs - start_fofs);
count = end_fofs - pgofs + 1;
if (count < (UINT_MAX >> blkbits))
bh_result->b_size = (count << blkbits);
else
bh_result->b_size = UINT_MAX;
sbi->read_hit_ext++;
read_unlock(&fi->ext.ext_lock);
return 1;
}
read_unlock(&fi->ext.ext_lock);
return 0;
}
void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
{
struct f2fs_inode_info *fi = F2FS_I(dn->inode);
pgoff_t fofs, start_fofs, end_fofs;
block_t start_blkaddr, end_blkaddr;
BUG_ON(blk_addr == NEW_ADDR);
fofs = start_bidx_of_node(ofs_of_node(dn->node_page)) + dn->ofs_in_node;
/* Update the page address in the parent node */
__set_data_blkaddr(dn, blk_addr);
write_lock(&fi->ext.ext_lock);
start_fofs = fi->ext.fofs;
end_fofs = fi->ext.fofs + fi->ext.len - 1;
start_blkaddr = fi->ext.blk_addr;
end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
/* Drop and initialize the matched extent */
if (fi->ext.len == 1 && fofs == start_fofs)
fi->ext.len = 0;
/* Initial extent */
if (fi->ext.len == 0) {
if (blk_addr != NULL_ADDR) {
fi->ext.fofs = fofs;
fi->ext.blk_addr = blk_addr;
fi->ext.len = 1;
}
goto end_update;
}
/* Front merge */
if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
fi->ext.fofs--;
fi->ext.blk_addr--;
fi->ext.len++;
goto end_update;
}
/* Back merge */
if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
fi->ext.len++;
goto end_update;
}
/* Split the existing extent */
if (fi->ext.len > 1 &&
fofs >= start_fofs && fofs <= end_fofs) {
if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
fi->ext.len = fofs - start_fofs;
} else {
fi->ext.fofs = fofs + 1;
fi->ext.blk_addr = start_blkaddr +
fofs - start_fofs + 1;
fi->ext.len -= fofs - start_fofs + 1;
}
goto end_update;
}
write_unlock(&fi->ext.ext_lock);
return;
end_update:
write_unlock(&fi->ext.ext_lock);
sync_inode_page(dn);
return;
}
struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
struct dnode_of_data dn;
struct page *page;
int err;
page = find_get_page(mapping, index);
if (page && PageUptodate(page))
return page;
f2fs_put_page(page, 0);
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
if (err)
return ERR_PTR(err);
f2fs_put_dnode(&dn);
if (dn.data_blkaddr == NULL_ADDR)
return ERR_PTR(-ENOENT);
/* By fallocate(), there is no cached page, but with NEW_ADDR */
if (dn.data_blkaddr == NEW_ADDR)
return ERR_PTR(-EINVAL);
page = grab_cache_page(mapping, index);
if (!page)
return ERR_PTR(-ENOMEM);
if (PageUptodate(page)) {
unlock_page(page);
return page;
}
err = f2fs_readpage(sbi, page, dn.data_blkaddr,
sync ? READ_SYNC : READA);
if (sync) {
wait_on_page_locked(page);
if (!PageUptodate(page)) {
f2fs_put_page(page, 0);
return ERR_PTR(-EIO);
}
}
return page;
}
/*
* If it tries to access a hole, return an error.
* Because, the callers, functions in dir.c and GC, should be able to know
* whether this page exists or not.
*/
struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
struct dnode_of_data dn;
struct page *page;
int err;
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
if (err)
return ERR_PTR(err);
f2fs_put_dnode(&dn);
if (dn.data_blkaddr == NULL_ADDR)
return ERR_PTR(-ENOENT);
repeat:
page = grab_cache_page(mapping, index);
if (!page)
return ERR_PTR(-ENOMEM);
if (PageUptodate(page))
return page;
BUG_ON(dn.data_blkaddr == NEW_ADDR);
BUG_ON(dn.data_blkaddr == NULL_ADDR);
err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
if (err)
return ERR_PTR(err);
lock_page(page);
if (!PageUptodate(page)) {
f2fs_put_page(page, 1);
return ERR_PTR(-EIO);
}
if (page->mapping != mapping) {
f2fs_put_page(page, 1);
goto repeat;
}
return page;
}
/*
* Caller ensures that this data page is never allocated.
* A new zero-filled data page is allocated in the page cache.
*
* Also, caller should grab and release a mutex by calling mutex_lock_op() and
* mutex_unlock_op().
*/
struct page *get_new_data_page(struct inode *inode, pgoff_t index,
bool new_i_size)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
struct page *page;
struct dnode_of_data dn;
int err;
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, index, ALLOC_NODE);
if (err)
return ERR_PTR(err);
if (dn.data_blkaddr == NULL_ADDR) {
if (reserve_new_block(&dn)) {
f2fs_put_dnode(&dn);
return ERR_PTR(-ENOSPC);
}
}
f2fs_put_dnode(&dn);
repeat:
page = grab_cache_page(mapping, index);
if (!page)
return ERR_PTR(-ENOMEM);
if (PageUptodate(page))
return page;
if (dn.data_blkaddr == NEW_ADDR) {
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
SetPageUptodate(page);
} else {
err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
if (err)
return ERR_PTR(err);
lock_page(page);
if (!PageUptodate(page)) {
f2fs_put_page(page, 1);
return ERR_PTR(-EIO);
}
if (page->mapping != mapping) {
f2fs_put_page(page, 1);
goto repeat;
}
}
if (new_i_size &&
i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
mark_inode_dirty_sync(inode);
}
return page;
}
static void read_end_io(struct bio *bio, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
do {
struct page *page = bvec->bv_page;
if (--bvec >= bio->bi_io_vec)
prefetchw(&bvec->bv_page->flags);
if (uptodate) {
SetPageUptodate(page);
} else {
ClearPageUptodate(page);
SetPageError(page);
}
unlock_page(page);
} while (bvec >= bio->bi_io_vec);
kfree(bio->bi_private);
bio_put(bio);
}
/*
* Fill the locked page with data located in the block address.
* Return unlocked page.
*/
int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
block_t blk_addr, int type)
{
struct block_device *bdev = sbi->sb->s_bdev;
struct bio *bio;
trace_f2fs_readpage(page, blk_addr, type);
down_read(&sbi->bio_sem);
/* Allocate a new bio */
bio = f2fs_bio_alloc(bdev, 1);
/* Initialize the bio */
bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
bio->bi_end_io = read_end_io;
if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
kfree(bio->bi_private);
bio_put(bio);
up_read(&sbi->bio_sem);
f2fs_put_page(page, 1);
return -EFAULT;
}
submit_bio(type, bio);
up_read(&sbi->bio_sem);
return 0;
}
/*
* This function should be used by the data read flow only where it
* does not check the "create" flag that indicates block allocation.
* The reason for this special functionality is to exploit VFS readahead
* mechanism.
*/
static int get_data_block_ro(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
unsigned int blkbits = inode->i_sb->s_blocksize_bits;
unsigned maxblocks = bh_result->b_size >> blkbits;
struct dnode_of_data dn;
pgoff_t pgofs;
int err;
/* Get the page offset from the block offset(iblock) */
pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
if (check_extent_cache(inode, pgofs, bh_result)) {
trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
return 0;
}
/* When reading holes, we need its node page */
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
if (err) {
trace_f2fs_get_data_block(inode, iblock, bh_result, err);
return (err == -ENOENT) ? 0 : err;
}
/* It does not support data allocation */
BUG_ON(create);
if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
int i;
unsigned int end_offset;
end_offset = IS_INODE(dn.node_page) ?
ADDRS_PER_INODE :
ADDRS_PER_BLOCK;
clear_buffer_new(bh_result);
/* Give more consecutive addresses for the read ahead */
for (i = 0; i < end_offset - dn.ofs_in_node; i++)
if (((datablock_addr(dn.node_page,
dn.ofs_in_node + i))
!= (dn.data_blkaddr + i)) || maxblocks == i)
break;
map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
bh_result->b_size = (i << blkbits);
}
f2fs_put_dnode(&dn);
trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
return 0;
}
static int f2fs_read_data_page(struct file *file, struct page *page)
{
return mpage_readpage(page, get_data_block_ro);
}
static int f2fs_read_data_pages(struct file *file,
struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
}
int do_write_data_page(struct page *page)
{
struct inode *inode = page->mapping->host;
block_t old_blk_addr, new_blk_addr;
struct dnode_of_data dn;
int err = 0;
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
if (err)
return err;
old_blk_addr = dn.data_blkaddr;
/* This page is already truncated */
if (old_blk_addr == NULL_ADDR)
goto out_writepage;
set_page_writeback(page);
/*
* If current allocation needs SSR,
* it had better in-place writes for updated data.
*/
if (old_blk_addr != NEW_ADDR && !is_cold_data(page) &&
need_inplace_update(inode)) {
rewrite_data_page(F2FS_SB(inode->i_sb), page,
old_blk_addr);
} else {
write_data_page(inode, page, &dn,
old_blk_addr, &new_blk_addr);
update_extent_cache(new_blk_addr, &dn);
}
out_writepage:
f2fs_put_dnode(&dn);
return err;
}
static int f2fs_write_data_page(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
loff_t i_size = i_size_read(inode);
const pgoff_t end_index = ((unsigned long long) i_size)
>> PAGE_CACHE_SHIFT;
unsigned offset;
bool need_balance_fs = false;
int err = 0;
if (page->index < end_index)
goto write;
/*
* If the offset is out-of-range of file size,
* this page does not have to be written to disk.
*/
offset = i_size & (PAGE_CACHE_SIZE - 1);
if ((page->index >= end_index + 1) || !offset) {
if (S_ISDIR(inode->i_mode)) {
dec_page_count(sbi, F2FS_DIRTY_DENTS);
inode_dec_dirty_dents(inode);
}
goto out;
}
zero_user_segment(page, offset, PAGE_CACHE_SIZE);
write:
if (sbi->por_doing) {
err = AOP_WRITEPAGE_ACTIVATE;
goto redirty_out;
}
/* Dentry blocks are controlled by checkpoint */
if (S_ISDIR(inode->i_mode)) {
dec_page_count(sbi, F2FS_DIRTY_DENTS);
inode_dec_dirty_dents(inode);
err = do_write_data_page(page);
} else {
int ilock = mutex_lock_op(sbi);
err = do_write_data_page(page);
mutex_unlock_op(sbi, ilock);
need_balance_fs = true;
}
if (err == -ENOENT)
goto out;
else if (err)
goto redirty_out;
if (wbc->for_reclaim)
f2fs_submit_bio(sbi, DATA, true);
clear_cold_data(page);
out:
unlock_page(page);
if (need_balance_fs)
f2fs_balance_fs(sbi);
return 0;
redirty_out:
wbc->pages_skipped++;
set_page_dirty(page);
return err;
}
#define MAX_DESIRED_PAGES_WP 4096
static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
void *data)
{
struct address_space *mapping = data;
int ret = mapping->a_ops->writepage(page, wbc);
mapping_set_error(mapping, ret);
return ret;
}
static int f2fs_write_data_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
bool locked = false;
int ret;
long excess_nrtw = 0, desired_nrtw;
/* deal with chardevs and other special file */
if (!mapping->a_ops->writepage)
return 0;
if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
desired_nrtw = MAX_DESIRED_PAGES_WP;
excess_nrtw = desired_nrtw - wbc->nr_to_write;
wbc->nr_to_write = desired_nrtw;
}
if (!S_ISDIR(inode->i_mode)) {
mutex_lock(&sbi->writepages);
locked = true;
}
ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
if (locked)
mutex_unlock(&sbi->writepages);
f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));
remove_dirty_dir_inode(inode);
wbc->nr_to_write -= excess_nrtw;
return ret;
}
static int f2fs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct page *page;
pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
struct dnode_of_data dn;
int err = 0;
int ilock;
/* for nobh_write_end */
*fsdata = NULL;
f2fs_balance_fs(sbi);
repeat:
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
*pagep = page;
ilock = mutex_lock_op(sbi);
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, index, ALLOC_NODE);
if (err)
goto err;
if (dn.data_blkaddr == NULL_ADDR)
err = reserve_new_block(&dn);
f2fs_put_dnode(&dn);
if (err)
goto err;
mutex_unlock_op(sbi, ilock);
if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
return 0;
if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
unsigned start = pos & (PAGE_CACHE_SIZE - 1);
unsigned end = start + len;
/* Reading beyond i_size is simple: memset to zero */
zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
goto out;
}
if (dn.data_blkaddr == NEW_ADDR) {
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
} else {
err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
if (err)
return err;
lock_page(page);
if (!PageUptodate(page)) {
f2fs_put_page(page, 1);
return -EIO;
}
if (page->mapping != mapping) {
f2fs_put_page(page, 1);
goto repeat;
}
}
out:
SetPageUptodate(page);
clear_cold_data(page);
return 0;
err:
mutex_unlock_op(sbi, ilock);
f2fs_put_page(page, 1);
return err;
}
static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
const struct iovec *iov, loff_t offset, unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
if (rw == WRITE)
return 0;
/* Needs synchronization with the cleaner */
return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
get_data_block_ro);
}
static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
unsigned int length)
{
struct inode *inode = page->mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
dec_page_count(sbi, F2FS_DIRTY_DENTS);
inode_dec_dirty_dents(inode);
}
ClearPagePrivate(page);
}
static int f2fs_release_data_page(struct page *page, gfp_t wait)
{
ClearPagePrivate(page);
return 1;
}
static int f2fs_set_data_page_dirty(struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
SetPageUptodate(page);
if (!PageDirty(page)) {
__set_page_dirty_nobuffers(page);
set_dirty_dir_page(inode, page);
return 1;
}
return 0;
}
static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping, block, get_data_block_ro);
}
const struct address_space_operations f2fs_dblock_aops = {
.readpage = f2fs_read_data_page,
.readpages = f2fs_read_data_pages,
.writepage = f2fs_write_data_page,
.writepages = f2fs_write_data_pages,
.write_begin = f2fs_write_begin,
.write_end = nobh_write_end,
.set_page_dirty = f2fs_set_data_page_dirty,
.invalidatepage = f2fs_invalidate_data_page,
.releasepage = f2fs_release_data_page,
.direct_IO = f2fs_direct_IO,
.bmap = f2fs_bmap,
};