/*
* 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) || buffer_mapped(bh))
goto failed_bh;
#if 0
/* The uptodate flag is not protected by the page lock, but
the mapped flag is. Thus, we don't have to wait the buffer. */
wait_on_buffer(bh);
if (buffer_uptodate(bh))
goto failed_bh;
#endif
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;
unsigned long 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;
}
if (!buffer_mapped(bh)) { /* unused buffer */
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 = 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,
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;
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, 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, &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 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) {
writer = nilfs_get_writer(NILFS_MDT(inode)->mi_nilfs);
if (!writer)
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)
nilfs_put_writer(NILFS_MDT(inode)->mi_nilfs);
return err;
}
static struct address_space_operations def_mdt_aops = {
.writepage = nilfs_mdt_write_page,
.sync_page = block_sync_page,
};
static struct inode_operations def_mdt_iops;
static 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.
*/
struct inode *
nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
ino_t ino, gfp_t gfp_mask)
{
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 = kzalloc(sizeof(*mi), 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, gfp_t gfp_mask)
{
struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino, gfp_mask);
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;
}
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);
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);
kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
kfree(mdi);
nilfs_destroy_inode(inode);
}
