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c11abd1a80
linux/fs/f2fs/data.c
Jaegeuk Kim c11abd1a80 f2fs: disable the extent cache ops on high fragmented files 
The f2fs manages an extent cache to search a number of consecutive data blocks
very quickly.

However it conducts unnecessary cache operations if the file is highly
fragmented with no valid extent cache.

In such the case, we don't need to handle the extent cache, but just can disable
the cache facility.

Nevertheless, this patch gives one more chance to enable the extent cache.

For example,
1. create a file
2. write data sequentially which produces a large valid extent cache
3. update some data, resulting in a fragmented extent
4. if the fragmented extent is too small, then drop extent cache
5. close the file

6. open the file again
7. give another chance to make a new extent cache
8. write data sequentially again which creates another big extent cache.
...

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-12-23 10:18:01 +09:00

797 lines
19 KiB
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/*
* 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;
f2fs_wait_on_page_writeback(node_page, NODE, false);
rn = F2FS_NODE(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);
pgoff_t start_fofs, end_fofs;
block_t start_blkaddr;
if (is_inode_flag_set(fi, FI_NO_EXTENT))
return 0;
read_lock(&fi->ext.ext_lock);
if (fi->ext.len == 0) {
read_unlock(&fi->ext.ext_lock);
return 0;
}
stat_inc_total_hit(inode->i_sb);
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;
stat_inc_read_hit(inode->i_sb);
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;
int need_update = true;
f2fs_bug_on(blk_addr == NEW_ADDR);
fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
dn->ofs_in_node;
/* Update the page address in the parent node */
__set_data_blkaddr(dn, blk_addr);
if (is_inode_flag_set(fi, FI_NO_EXTENT))
return;
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;
}
} else {
need_update = false;
}
/* Finally, if the extent is very fragmented, let's drop the cache. */
if (fi->ext.len < F2FS_MIN_EXTENT_LEN) {
fi->ext.len = 0;
set_inode_flag(fi, FI_NO_EXTENT);
need_update = true;
}
end_update:
write_unlock(&fi->ext.ext_lock);
if (need_update)
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_write_begin(mapping, index, AOP_FLAG_NOFS);
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;
repeat:
page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
if (!page)
return ERR_PTR(-ENOMEM);
set_new_dnode(&dn, inode, NULL, NULL, 0);
err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
if (err) {
f2fs_put_page(page, 1);
return ERR_PTR(err);
}
f2fs_put_dnode(&dn);
if (dn.data_blkaddr == NULL_ADDR) {
f2fs_put_page(page, 1);
return ERR_PTR(-ENOENT);
}
if (PageUptodate(page))
return page;
/*
* A new dentry page is allocated but not able to be written, since its
* new inode page couldn't be allocated due to -ENOSPC.
* In such the case, its blkaddr can be remained as NEW_ADDR.
* see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
*/
if (dn.data_blkaddr == NEW_ADDR) {
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
SetPageUptodate(page);
return page;
}
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().
* Note that, npage is set only by make_empty_dir.
*/
struct page *get_new_data_page(struct inode *inode,
struct page *npage, 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, npage, npage, 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)) {
if (!npage)
f2fs_put_dnode(&dn);
return ERR_PTR(-ENOSPC);
}
}
if (!npage)
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));
/* Only the directory inode sets new_i_size */
set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR);
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);
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);
/* 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) {
bio_put(bio);
f2fs_put_page(page, 1);
return -EFAULT;
}
submit_bio(type, bio);
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 */
f2fs_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(F2FS_I(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 (unlikely(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 {
f2fs_lock_op(sbi);
err = do_write_data_page(page);
f2fs_unlock_op(sbi);
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;
f2fs_balance_fs(sbi);
repeat:
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
*pagep = page;
f2fs_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;
f2fs_unlock_op(sbi);
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:
f2fs_unlock_op(sbi);
f2fs_put_page(page, 1);
return err;
}
static int f2fs_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = page->mapping->host;
SetPageUptodate(page);
set_page_dirty(page);
if (pos + copied > i_size_read(inode)) {
i_size_write(inode, pos + copied);
mark_inode_dirty(inode);
update_inode_page(inode);
}
f2fs_put_page(page, 1);
return copied;
}
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;
trace_f2fs_set_page_dirty(page, DATA);
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 = f2fs_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,
};
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