linux/fs/nilfs2/mdt.c
Ryusuke Konishi db38d5ad32 nilfs2: add cache framework for persistent object allocator
This adds setup and cleanup routines of the persistent object
allocator cache.

According to ftrace analyses, accessing buffers of the DAT file
suffers indispensable overhead many times.  To mitigate the overhead,
This introduce cache framework for the persistent object allocator
(palloc) which the DAT file and ifile are using.

struct nilfs_palloc_cache represents the cache object per metadata
file using palloc.

The cache is initialized through nilfs_palloc_setup_cache() and
destroyed by nilfs_palloc_destroy_cache(); callers of the former
function will be added to individual allocators of DAT and ifile on
successive patches.

nilfs_palloc_destroy_cache() will be called from nilfs_mdt_destroy()
if the cache is attached to a metadata file.  A companion function
nilfs_palloc_clear_cache() is provided to allow releasing buffer head
references independently with the cleanup task.  This adjunctive
function will be used before invalidating pages of metadata file with
the cache.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2009-11-20 10:05:50 +09:00

582 lines
14 KiB
C

/*
* mdt.c - meta data file for NILFS
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Written by Ryusuke Konishi <ryusuke@osrg.net>
*/
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/mm.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/swap.h>
#include "nilfs.h"
#include "segment.h"
#include "page.h"
#include "mdt.h"
#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
#define INIT_UNUSED_INODE_FIELDS
static int
nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
struct buffer_head *bh,
void (*init_block)(struct inode *,
struct buffer_head *, void *))
{
struct nilfs_inode_info *ii = NILFS_I(inode);
void *kaddr;
int ret;
/* Caller exclude read accesses using page lock */
/* set_buffer_new(bh); */
bh->b_blocknr = 0;
ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
if (unlikely(ret))
return ret;
set_buffer_mapped(bh);
kaddr = kmap_atomic(bh->b_page, KM_USER0);
memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
if (init_block)
init_block(inode, bh, kaddr);
flush_dcache_page(bh->b_page);
kunmap_atomic(kaddr, KM_USER0);
set_buffer_uptodate(bh);
nilfs_mark_buffer_dirty(bh);
nilfs_mdt_mark_dirty(inode);
return 0;
}
static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
struct buffer_head **out_bh,
void (*init_block)(struct inode *,
struct buffer_head *,
void *))
{
struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
struct super_block *sb = inode->i_sb;
struct nilfs_transaction_info ti;
struct buffer_head *bh;
int err;
if (!sb) {
/*
* Make sure this function is not called from any
* read-only context.
*/
if (!nilfs->ns_writer) {
WARN_ON(1);
err = -EROFS;
goto out;
}
sb = nilfs->ns_writer->s_super;
}
nilfs_transaction_begin(sb, &ti, 0);
err = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
if (unlikely(!bh))
goto failed_unlock;
err = -EEXIST;
if (buffer_uptodate(bh))
goto failed_bh;
wait_on_buffer(bh);
if (buffer_uptodate(bh))
goto failed_bh;
bh->b_bdev = nilfs->ns_bdev;
err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
if (likely(!err)) {
get_bh(bh);
*out_bh = bh;
}
failed_bh:
unlock_page(bh->b_page);
page_cache_release(bh->b_page);
brelse(bh);
failed_unlock:
if (likely(!err))
err = nilfs_transaction_commit(sb);
else
nilfs_transaction_abort(sb);
out:
return err;
}
static int
nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
int mode, struct buffer_head **out_bh)
{
struct buffer_head *bh;
__u64 blknum = 0;
int ret = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
if (unlikely(!bh))
goto failed;
ret = -EEXIST; /* internal code */
if (buffer_uptodate(bh))
goto out;
if (mode == READA) {
if (!trylock_buffer(bh)) {
ret = -EBUSY;
goto failed_bh;
}
} else /* mode == READ */
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
goto out;
}
ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
if (unlikely(ret)) {
unlock_buffer(bh);
goto failed_bh;
}
bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
bh->b_blocknr = (sector_t)blknum;
set_buffer_mapped(bh);
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(mode, bh);
ret = 0;
out:
get_bh(bh);
*out_bh = bh;
failed_bh:
unlock_page(bh->b_page);
page_cache_release(bh->b_page);
brelse(bh);
failed:
return ret;
}
static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
int readahead, struct buffer_head **out_bh)
{
struct buffer_head *first_bh, *bh;
unsigned long blkoff;
int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
int err;
err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
if (err == -EEXIST) /* internal code */
goto out;
if (unlikely(err))
goto failed;
if (readahead) {
blkoff = block + 1;
for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
if (likely(!err || err == -EEXIST))
brelse(bh);
else if (err != -EBUSY)
break;
/* abort readahead if bmap lookup failed */
if (!buffer_locked(first_bh))
goto out_no_wait;
}
}
wait_on_buffer(first_bh);
out_no_wait:
err = -EIO;
if (!buffer_uptodate(first_bh))
goto failed_bh;
out:
*out_bh = first_bh;
return 0;
failed_bh:
brelse(first_bh);
failed:
return err;
}
/**
* nilfs_mdt_get_block - read or create a buffer on meta data file.
* @inode: inode of the meta data file
* @blkoff: block offset
* @create: create flag
* @init_block: initializer used for newly allocated block
* @out_bh: output of a pointer to the buffer_head
*
* nilfs_mdt_get_block() looks up the specified buffer and tries to create
* a new buffer if @create is not zero. On success, the returned buffer is
* assured to be either existing or formatted using a buffer lock on success.
* @out_bh is substituted only when zero is returned.
*
* Return Value: On success, it returns 0. On error, the following negative
* error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*
* %-ENOENT - the specified block does not exist (hole block)
*
* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
*
* %-EROFS - Read only filesystem (for create mode)
*/
int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
void (*init_block)(struct inode *,
struct buffer_head *, void *),
struct buffer_head **out_bh)
{
int ret;
/* Should be rewritten with merging nilfs_mdt_read_block() */
retry:
ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
if (!create || ret != -ENOENT)
return ret;
ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
if (unlikely(ret == -EEXIST)) {
/* create = 0; */ /* limit read-create loop retries */
goto retry;
}
return ret;
}
/**
* nilfs_mdt_delete_block - make a hole on the meta data file.
* @inode: inode of the meta data file
* @block: block offset
*
* Return Value: On success, zero is returned.
* On error, one of the following negative error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*
* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
*/
int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
int err;
err = nilfs_bmap_delete(ii->i_bmap, block);
if (!err || err == -ENOENT) {
nilfs_mdt_mark_dirty(inode);
nilfs_mdt_forget_block(inode, block);
}
return err;
}
/**
* nilfs_mdt_forget_block - discard dirty state and try to remove the page
* @inode: inode of the meta data file
* @block: block offset
*
* nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
* tries to release the page including the buffer from a page cache.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error code is returned.
*
* %-EBUSY - page has an active buffer.
*
* %-ENOENT - page cache has no page addressed by the offset.
*/
int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
{
pgoff_t index = (pgoff_t)block >>
(PAGE_CACHE_SHIFT - inode->i_blkbits);
struct page *page;
unsigned long first_block;
int ret = 0;
int still_dirty;
page = find_lock_page(inode->i_mapping, index);
if (!page)
return -ENOENT;
wait_on_page_writeback(page);
first_block = (unsigned long)index <<
(PAGE_CACHE_SHIFT - inode->i_blkbits);
if (page_has_buffers(page)) {
struct buffer_head *bh;
bh = nilfs_page_get_nth_block(page, block - first_block);
nilfs_forget_buffer(bh);
}
still_dirty = PageDirty(page);
unlock_page(page);
page_cache_release(page);
if (still_dirty ||
invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
ret = -EBUSY;
return ret;
}
/**
* nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty.
* @inode: inode of the meta data file
* @block: block offset
*
* Return Value: On success, it returns 0. On error, the following negative
* error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*
* %-ENOENT - the specified block does not exist (hole block)
*
* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
*/
int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
{
struct buffer_head *bh;
int err;
err = nilfs_mdt_read_block(inode, block, 0, &bh);
if (unlikely(err))
return err;
nilfs_mark_buffer_dirty(bh);
nilfs_mdt_mark_dirty(inode);
brelse(bh);
return 0;
}
int nilfs_mdt_fetch_dirty(struct inode *inode)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
set_bit(NILFS_I_DIRTY, &ii->i_state);
return 1;
}
return test_bit(NILFS_I_DIRTY, &ii->i_state);
}
static int
nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
{
struct inode *inode = container_of(page->mapping,
struct inode, i_data);
struct super_block *sb = inode->i_sb;
struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
struct nilfs_sb_info *writer = NULL;
int err = 0;
redirty_page_for_writepage(wbc, page);
unlock_page(page);
if (page->mapping->assoc_mapping)
return 0; /* Do not request flush for shadow page cache */
if (!sb) {
down_read(&nilfs->ns_writer_sem);
writer = nilfs->ns_writer;
if (!writer) {
up_read(&nilfs->ns_writer_sem);
return -EROFS;
}
sb = writer->s_super;
}
if (wbc->sync_mode == WB_SYNC_ALL)
err = nilfs_construct_segment(sb);
else if (wbc->for_reclaim)
nilfs_flush_segment(sb, inode->i_ino);
if (writer)
up_read(&nilfs->ns_writer_sem);
return err;
}
static const struct address_space_operations def_mdt_aops = {
.writepage = nilfs_mdt_write_page,
.sync_page = block_sync_page,
};
static const struct inode_operations def_mdt_iops;
static const struct file_operations def_mdt_fops;
/*
* NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,
* ifile, or gcinodes. This allows the B-tree code and segment constructor
* to treat them like regular files, and this helps to simplify the
* implementation.
* On the other hand, some of the pseudo inodes have an irregular point:
* They don't have valid inode->i_sb pointer because their lifetimes are
* longer than those of the super block structs; they may continue for
* several consecutive mounts/umounts. This would need discussions.
*/
/**
* nilfs_mdt_new_common - allocate a pseudo inode for metadata file
* @nilfs: nilfs object
* @sb: super block instance the metadata file belongs to
* @ino: inode number
* @gfp_mask: gfp mask for data pages
* @objsz: size of the private object attached to inode->i_private
*/
struct inode *
nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
ino_t ino, gfp_t gfp_mask, size_t objsz)
{
struct inode *inode = nilfs_alloc_inode_common(nilfs);
if (!inode)
return NULL;
else {
struct address_space * const mapping = &inode->i_data;
struct nilfs_mdt_info *mi;
mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
if (!mi) {
nilfs_destroy_inode(inode);
return NULL;
}
mi->mi_nilfs = nilfs;
init_rwsem(&mi->mi_sem);
inode->i_sb = sb; /* sb may be NULL for some meta data files */
inode->i_blkbits = nilfs->ns_blocksize_bits;
inode->i_flags = 0;
atomic_set(&inode->i_count, 1);
inode->i_nlink = 1;
inode->i_ino = ino;
inode->i_mode = S_IFREG;
inode->i_private = mi;
#ifdef INIT_UNUSED_INODE_FIELDS
atomic_set(&inode->i_writecount, 0);
inode->i_size = 0;
inode->i_blocks = 0;
inode->i_bytes = 0;
inode->i_generation = 0;
#ifdef CONFIG_QUOTA
memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
#endif
inode->i_pipe = NULL;
inode->i_bdev = NULL;
inode->i_cdev = NULL;
inode->i_rdev = 0;
#ifdef CONFIG_SECURITY
inode->i_security = NULL;
#endif
inode->dirtied_when = 0;
INIT_LIST_HEAD(&inode->i_list);
INIT_LIST_HEAD(&inode->i_sb_list);
inode->i_state = 0;
#endif
spin_lock_init(&inode->i_lock);
mutex_init(&inode->i_mutex);
init_rwsem(&inode->i_alloc_sem);
mapping->host = NULL; /* instead of inode */
mapping->flags = 0;
mapping_set_gfp_mask(mapping, gfp_mask);
mapping->assoc_mapping = NULL;
mapping->backing_dev_info = nilfs->ns_bdi;
inode->i_mapping = mapping;
}
return inode;
}
struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
ino_t ino, size_t objsz)
{
struct inode *inode;
inode = nilfs_mdt_new_common(nilfs, sb, ino, NILFS_MDT_GFP, objsz);
if (!inode)
return NULL;
inode->i_op = &def_mdt_iops;
inode->i_fop = &def_mdt_fops;
inode->i_mapping->a_ops = &def_mdt_aops;
return inode;
}
void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
unsigned header_size)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
mi->mi_entry_size = entry_size;
mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
}
void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow)
{
shadow->i_mapping->assoc_mapping = orig->i_mapping;
NILFS_I(shadow)->i_btnode_cache.assoc_mapping =
&NILFS_I(orig)->i_btnode_cache;
}
static void nilfs_mdt_clear(struct inode *inode)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
truncate_inode_pages(inode->i_mapping, 0);
if (test_bit(NILFS_I_BMAP, &ii->i_state))
nilfs_bmap_clear(ii->i_bmap);
nilfs_btnode_cache_clear(&ii->i_btnode_cache);
}
void nilfs_mdt_destroy(struct inode *inode)
{
struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
if (mdi->mi_palloc_cache)
nilfs_palloc_destroy_cache(inode);
nilfs_mdt_clear(inode);
kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
kfree(mdi);
nilfs_destroy_inode(inode);
}