[mirror_ubuntu-zesty-kernel.git] / fs / nilfs2 / mdt.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.
 *
 * Written by Ryusuke Konishi.
 */

#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 <linux/slab.h>
#include "nilfs.h"
#include "btnode.h"
#include "segment.h"
#include "page.h"
#include "mdt.h"
#include "alloc.h"		/* nilfs_palloc_destroy_cache() */

#include <trace/events/nilfs2.h>

#define NILFS_MDT_MAX_RA_BLOCKS		(16 - 1)


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);
	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);

	set_buffer_uptodate(bh);
	mark_buffer_dirty(bh);
	nilfs_mdt_mark_dirty(inode);

	trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);

	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 super_block *sb = inode->i_sb;
	struct nilfs_transaction_info ti;
	struct buffer_head *bh;
	int err;

	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 = sb->s_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);
	put_page(bh->b_page);
	brelse(bh);

 failed_unlock:
	if (likely(!err))
		err = nilfs_transaction_commit(sb);
	else
		nilfs_transaction_abort(sb);

	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;
	}
	map_bh(bh, inode->i_sb, (sector_t)blknum);

	bh->b_end_io = end_buffer_read_sync;
	get_bh(bh);
	submit_bh(mode, bh);
	ret = 0;

	trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
 out:
	get_bh(bh);
	*out_bh = bh;

 failed_bh:
	unlock_page(bh->b_page);
	put_page(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)
 *
 * %-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_find_block - find and get a buffer on meta data file.
 * @inode: inode of the meta data file
 * @start: start block offset (inclusive)
 * @end: end block offset (inclusive)
 * @blkoff: block offset
 * @out_bh: place to store a pointer to buffer_head struct
 *
 * nilfs_mdt_find_block() looks up an existing block in range of
 * [@start, @end] and stores pointer to a buffer head of the block to
 * @out_bh, and block offset to @blkoff, respectively.  @out_bh and
 * @blkoff are 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 - no block was found in the range
 */
int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
			 unsigned long end, unsigned long *blkoff,
			 struct buffer_head **out_bh)
{
	__u64 next;
	int ret;

	if (unlikely(start > end))
		return -ENOENT;

	ret = nilfs_mdt_read_block(inode, start, true, out_bh);
	if (!ret) {
		*blkoff = start;
		goto out;
	}
	if (unlikely(ret != -ENOENT || start == ULONG_MAX))
		goto out;

	ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
	if (!ret) {
		if (next <= end) {
			ret = nilfs_mdt_read_block(inode, next, true, out_bh);
			if (!ret)
				*blkoff = next;
		} else {
			ret = -ENOENT;
		}
	}
out:
	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
 */
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_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_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);
	put_page(page);

	if (still_dirty ||
	    invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
		ret = -EBUSY;
	return ret;
}

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 = page->mapping->host;
	struct super_block *sb;
	int err = 0;

	if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
		/*
		 * It means that filesystem was remounted in read-only
		 * mode because of error or metadata corruption. But we
		 * have dirty pages that try to be flushed in background.
		 * So, here we simply discard this dirty page.
		 */
		nilfs_clear_dirty_page(page, false);
		unlock_page(page);
		return -EROFS;
	}

	redirty_page_for_writepage(wbc, page);
	unlock_page(page);

	if (!inode)
		return 0;

	sb = inode->i_sb;

	if (wbc->sync_mode == WB_SYNC_ALL)
		err = nilfs_construct_segment(sb);
	else if (wbc->for_reclaim)
		nilfs_flush_segment(sb, inode->i_ino);

	return err;
}


static const struct address_space_operations def_mdt_aops = {
	.writepage		= nilfs_mdt_write_page,
};

static const struct inode_operations def_mdt_iops;
static const struct file_operations def_mdt_fops;


int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
{
	struct nilfs_mdt_info *mi;

	mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
	if (!mi)
		return -ENOMEM;

	init_rwsem(&mi->mi_sem);
	inode->i_private = mi;

	inode->i_mode = S_IFREG;
	mapping_set_gfp_mask(inode->i_mapping, gfp_mask);

	inode->i_op = &def_mdt_iops;
	inode->i_fop = &def_mdt_fops;
	inode->i_mapping->a_ops = &def_mdt_aops;

	return 0;
}

/**
 * nilfs_mdt_clear - do cleanup for the metadata file
 * @inode: inode of the metadata file
 */
void nilfs_mdt_clear(struct inode *inode)
{
	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);

	if (mdi->mi_palloc_cache)
		nilfs_palloc_destroy_cache(inode);
}

/**
 * nilfs_mdt_destroy - release resources used by the metadata file
 * @inode: inode of the metadata file
 */
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);
}

void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
			      unsigned int 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);
}

/**
 * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
 * @inode: inode of the metadata file
 * @shadow: shadow mapping
 */
int nilfs_mdt_setup_shadow_map(struct inode *inode,
			       struct nilfs_shadow_map *shadow)
{
	struct nilfs_mdt_info *mi = NILFS_MDT(inode);

	INIT_LIST_HEAD(&shadow->frozen_buffers);
	address_space_init_once(&shadow->frozen_data);
	nilfs_mapping_init(&shadow->frozen_data, inode);
	address_space_init_once(&shadow->frozen_btnodes);
	nilfs_mapping_init(&shadow->frozen_btnodes, inode);
	mi->mi_shadow = shadow;
	return 0;
}

/**
 * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
 * @inode: inode of the metadata file
 */
int nilfs_mdt_save_to_shadow_map(struct inode *inode)
{
	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	struct nilfs_inode_info *ii = NILFS_I(inode);
	struct nilfs_shadow_map *shadow = mi->mi_shadow;
	int ret;

	ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
	if (ret)
		goto out;

	ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
				     &ii->i_btnode_cache);
	if (ret)
		goto out;

	nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
 out:
	return ret;
}

int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
{
	struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
	struct buffer_head *bh_frozen;
	struct page *page;
	int blkbits = inode->i_blkbits;

	page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
	if (!page)
		return -ENOMEM;

	if (!page_has_buffers(page))
		create_empty_buffers(page, 1 << blkbits, 0);

	bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);

	if (!buffer_uptodate(bh_frozen))
		nilfs_copy_buffer(bh_frozen, bh);
	if (list_empty(&bh_frozen->b_assoc_buffers)) {
		list_add_tail(&bh_frozen->b_assoc_buffers,
			      &shadow->frozen_buffers);
		set_buffer_nilfs_redirected(bh);
	} else {
		brelse(bh_frozen); /* already frozen */
	}

	unlock_page(page);
	put_page(page);
	return 0;
}

struct buffer_head *
nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
{
	struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
	struct buffer_head *bh_frozen = NULL;
	struct page *page;
	int n;

	page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
	if (page) {
		if (page_has_buffers(page)) {
			n = bh_offset(bh) >> inode->i_blkbits;
			bh_frozen = nilfs_page_get_nth_block(page, n);
		}
		unlock_page(page);
		put_page(page);
	}
	return bh_frozen;
}

static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
{
	struct list_head *head = &shadow->frozen_buffers;
	struct buffer_head *bh;

	while (!list_empty(head)) {
		bh = list_first_entry(head, struct buffer_head,
				      b_assoc_buffers);
		list_del_init(&bh->b_assoc_buffers);
		brelse(bh); /* drop ref-count to make it releasable */
	}
}

/**
 * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
 * @inode: inode of the metadata file
 */
void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
{
	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	struct nilfs_inode_info *ii = NILFS_I(inode);
	struct nilfs_shadow_map *shadow = mi->mi_shadow;

	down_write(&mi->mi_sem);

	if (mi->mi_palloc_cache)
		nilfs_palloc_clear_cache(inode);

	nilfs_clear_dirty_pages(inode->i_mapping, true);
	nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);

	nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
	nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);

	nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);

	up_write(&mi->mi_sem);
}

/**
 * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
 * @inode: inode of the metadata file
 */
void nilfs_mdt_clear_shadow_map(struct inode *inode)
{
	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	struct nilfs_shadow_map *shadow = mi->mi_shadow;

	down_write(&mi->mi_sem);
	nilfs_release_frozen_buffers(shadow);
	truncate_inode_pages(&shadow->frozen_data, 0);
	truncate_inode_pages(&shadow->frozen_btnodes, 0);
	up_write(&mi->mi_sem);
}
Commit	Line	Data
5eb563f5 RK	1	/*
	2	* mdt.c - meta data file for NILFS
	3	*
	4	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
4b420ab4	16	* Written by Ryusuke Konishi.
5eb563f5 RK	17	*/
	18
	19	#include <linux/buffer_head.h>
	20	#include <linux/mpage.h>
	21	#include <linux/mm.h>
	22	#include <linux/writeback.h>
	23	#include <linux/backing-dev.h>
	24	#include <linux/swap.h>
5a0e3ad6	25	#include <linux/slab.h>
5eb563f5	26	#include "nilfs.h"
05d0e94b	27	#include "btnode.h"
5eb563f5 RK	28	#include "segment.h"
	29	#include "page.h"
	30	#include "mdt.h"
2d19961d	31	#include "alloc.h" /* nilfs_palloc_destroy_cache() */
5eb563f5	32
a9cd207c	33	#include <trace/events/nilfs2.h>
5eb563f5 RK	34
	35	#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
	36
5eb563f5 RK	37
	38	static int
	39	nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
	40	struct buffer_head *bh,
	41	void (init_block)(struct inode ,
	42	struct buffer_head , void ))
	43	{
	44	struct nilfs_inode_info *ii = NILFS_I(inode);
	45	void *kaddr;
	46	int ret;
	47
	48	/* Caller exclude read accesses using page lock */
	49
	50	/* set_buffer_new(bh); */
	51	bh->b_blocknr = 0;
	52
	53	ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
	54	if (unlikely(ret))
	55	return ret;
	56
	57	set_buffer_mapped(bh);
	58
7b9c0976	59	kaddr = kmap_atomic(bh->b_page);
5eb563f5 RK	60	memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
	61	if (init_block)
	62	init_block(inode, bh, kaddr);
	63	flush_dcache_page(bh->b_page);
7b9c0976	64	kunmap_atomic(kaddr);
5eb563f5 RK	65
5eb563f5 RK	66	set_buffer_uptodate(bh);
5fc7b141	67	mark_buffer_dirty(bh);
5eb563f5	68	nilfs_mdt_mark_dirty(inode);
a9cd207c HM	69
	70	trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
	71
5eb563f5 RK	72	return 0;
	73	}
	74
	75	static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
	76	struct buffer_head **out_bh,
	77	void (init_block)(struct inode ,
	78	struct buffer_head *,
	79	void *))
	80	{
5eb563f5 RK	81	struct super_block *sb = inode->i_sb;
	82	struct nilfs_transaction_info ti;
	83	struct buffer_head *bh;
	84	int err;
	85
5eb563f5 RK	86	nilfs_transaction_begin(sb, &ti, 0);
	87
	88	err = -ENOMEM;
	89	bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
	90	if (unlikely(!bh))
	91	goto failed_unlock;
	92
	93	err = -EEXIST;
14351104	94	if (buffer_uptodate(bh))
5eb563f5	95	goto failed_bh;
14351104	96
5eb563f5 RK	97	wait_on_buffer(bh);
	98	if (buffer_uptodate(bh))
	99	goto failed_bh;
5eb563f5	100
090fd5b1	101	bh->b_bdev = sb->s_bdev;
5eb563f5 RK	102	err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
	103	if (likely(!err)) {
	104	get_bh(bh);
	105	*out_bh = bh;
	106	}
	107
	108	failed_bh:
	109	unlock_page(bh->b_page);
09cbfeaf	110	put_page(bh->b_page);
5eb563f5 RK	111	brelse(bh);
	112
	113	failed_unlock:
47420c79 RK	114	if (likely(!err))
	115	err = nilfs_transaction_commit(sb);
	116	else
	117	nilfs_transaction_abort(sb);
090fd5b1	118
5eb563f5 RK	119	return err;
	120	}
	121
	122	static int
	123	nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
	124	int mode, struct buffer_head **out_bh)
	125	{
	126	struct buffer_head *bh;
0f3fe33b	127	__u64 blknum = 0;
5eb563f5 RK	128	int ret = -ENOMEM;
	129
	130	bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
	131	if (unlikely(!bh))
	132	goto failed;
	133
	134	ret = -EEXIST; /* internal code */
	135	if (buffer_uptodate(bh))
	136	goto out;
	137
	138	if (mode == READA) {
	139	if (!trylock_buffer(bh)) {
	140	ret = -EBUSY;
	141	goto failed_bh;
	142	}
1f5abe7e	143	} else /* mode == READ */
5eb563f5	144	lock_buffer(bh);
5eb563f5 RK	145
	146	if (buffer_uptodate(bh)) {
	147	unlock_buffer(bh);
	148	goto out;
	149	}
14351104 RK	150
	151	ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
	152	if (unlikely(ret)) {
	153	unlock_buffer(bh);
	154	goto failed_bh;
5eb563f5	155	}
c6e07188	156	map_bh(bh, inode->i_sb, (sector_t)blknum);
5eb563f5 RK	157
	158	bh->b_end_io = end_buffer_read_sync;
	159	get_bh(bh);
	160	submit_bh(mode, bh);
	161	ret = 0;
a9cd207c HM	162
a9cd207c HM	163	trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
5eb563f5 RK	164	out:
	165	get_bh(bh);
	166	*out_bh = bh;
	167
	168	failed_bh:
	169	unlock_page(bh->b_page);
09cbfeaf	170	put_page(bh->b_page);
5eb563f5 RK	171	brelse(bh);
	172	failed:
	173	return ret;
	174	}
	175
	176	static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
b34a6506	177	int readahead, struct buffer_head **out_bh)
5eb563f5 RK	178	{
	179	struct buffer_head first_bh, bh;
	180	unsigned long blkoff;
	181	int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
	182	int err;
	183
	184	err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
	185	if (err == -EEXIST) /* internal code */
	186	goto out;
	187
	188	if (unlikely(err))
	189	goto failed;
	190
b34a6506 RK	191	if (readahead) {
	192	blkoff = block + 1;
	193	for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
	194	err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
	195	if (likely(!err \|\| err == -EEXIST))
	196	brelse(bh);
	197	else if (err != -EBUSY)
	198	break;
	199	/* abort readahead if bmap lookup failed */
	200	if (!buffer_locked(first_bh))
	201	goto out_no_wait;
	202	}
5eb563f5 RK	203	}
	204
	205	wait_on_buffer(first_bh);
	206
	207	out_no_wait:
	208	err = -EIO;
	209	if (!buffer_uptodate(first_bh))
	210	goto failed_bh;
	211	out:
	212	*out_bh = first_bh;
	213	return 0;
	214
	215	failed_bh:
	216	brelse(first_bh);
	217	failed:
	218	return err;
	219	}
	220
	221	/**
	222	* nilfs_mdt_get_block - read or create a buffer on meta data file.
	223	* @inode: inode of the meta data file
	224	* @blkoff: block offset
	225	* @create: create flag
	226	* @init_block: initializer used for newly allocated block
	227	* @out_bh: output of a pointer to the buffer_head
	228	*
	229	* nilfs_mdt_get_block() looks up the specified buffer and tries to create
	230	* a new buffer if @create is not zero. On success, the returned buffer is
	231	* assured to be either existing or formatted using a buffer lock on success.
	232	* @out_bh is substituted only when zero is returned.
	233	*
	234	* Return Value: On success, it returns 0. On error, the following negative
	235	* error code is returned.
	236	*
	237	* %-ENOMEM - Insufficient memory available.
	238	*
	239	* %-EIO - I/O error
	240	*
	241	* %-ENOENT - the specified block does not exist (hole block)
	242	*
5eb563f5 RK	243	* %-EROFS - Read only filesystem (for create mode)
	244	*/
	245	int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
	246	void (init_block)(struct inode ,
	247	struct buffer_head , void ),
	248	struct buffer_head **out_bh)
	249	{
	250	int ret;
	251
	252	/* Should be rewritten with merging nilfs_mdt_read_block() */
	253	retry:
b34a6506	254	ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
5eb563f5 RK	255	if (!create \|\| ret != -ENOENT)
	256	return ret;
	257
	258	ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
	259	if (unlikely(ret == -EEXIST)) {
	260	/* create = 0; / / limit read-create loop retries */
	261	goto retry;
	262	}
	263	return ret;
	264	}
	265
fa33915c RK	266	/**
	267	* nilfs_mdt_find_block - find and get a buffer on meta data file.
	268	* @inode: inode of the meta data file
	269	* @start: start block offset (inclusive)
	270	* @end: end block offset (inclusive)
	271	* @blkoff: block offset
	272	* @out_bh: place to store a pointer to buffer_head struct
	273	*
	274	* nilfs_mdt_find_block() looks up an existing block in range of
	275	* [@start, @end] and stores pointer to a buffer head of the block to
	276	* @out_bh, and block offset to @blkoff, respectively. @out_bh and
	277	* @blkoff are substituted only when zero is returned.
	278	*
	279	* Return Value: On success, it returns 0. On error, the following negative
	280	* error code is returned.
	281	*
	282	* %-ENOMEM - Insufficient memory available.
	283	*
	284	* %-EIO - I/O error
	285	*
	286	* %-ENOENT - no block was found in the range
	287	*/
	288	int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
	289	unsigned long end, unsigned long *blkoff,
	290	struct buffer_head **out_bh)
	291	{
	292	__u64 next;
	293	int ret;
	294
	295	if (unlikely(start > end))
	296	return -ENOENT;
	297
	298	ret = nilfs_mdt_read_block(inode, start, true, out_bh);
	299	if (!ret) {
	300	*blkoff = start;
	301	goto out;
	302	}
	303	if (unlikely(ret != -ENOENT \|\| start == ULONG_MAX))
	304	goto out;
	305
	306	ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
	307	if (!ret) {
	308	if (next <= end) {
	309	ret = nilfs_mdt_read_block(inode, next, true, out_bh);
	310	if (!ret)
	311	*blkoff = next;
	312	} else {
	313	ret = -ENOENT;
	314	}
	315	}
	316	out:
	317	return ret;
	318	}
	319
5eb563f5 RK	320	/**
	321	* nilfs_mdt_delete_block - make a hole on the meta data file.
	322	* @inode: inode of the meta data file
	323	* @block: block offset
	324	*
	325	* Return Value: On success, zero is returned.
	326	* On error, one of the following negative error code is returned.
	327	*
	328	* %-ENOMEM - Insufficient memory available.
	329	*
	330	* %-EIO - I/O error
5eb563f5 RK	331	*/
	332	int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
	333	{
	334	struct nilfs_inode_info *ii = NILFS_I(inode);
	335	int err;
	336
	337	err = nilfs_bmap_delete(ii->i_bmap, block);
84338237	338	if (!err \|\| err == -ENOENT) {
5eb563f5 RK	339	nilfs_mdt_mark_dirty(inode);
	340	nilfs_mdt_forget_block(inode, block);
	341	}
	342	return err;
	343	}
	344
	345	/**
	346	* nilfs_mdt_forget_block - discard dirty state and try to remove the page
	347	* @inode: inode of the meta data file
	348	* @block: block offset
	349	*
	350	* nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
	351	* tries to release the page including the buffer from a page cache.
	352	*
	353	* Return Value: On success, 0 is returned. On error, one of the following
	354	* negative error code is returned.
	355	*
	356	* %-EBUSY - page has an active buffer.
	357	*
	358	* %-ENOENT - page cache has no page addressed by the offset.
	359	*/
	360	int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
	361	{
	362	pgoff_t index = (pgoff_t)block >>
09cbfeaf	363	(PAGE_SHIFT - inode->i_blkbits);
5eb563f5 RK	364	struct page *page;
	365	unsigned long first_block;
	366	int ret = 0;
	367	int still_dirty;
	368
	369	page = find_lock_page(inode->i_mapping, index);
	370	if (!page)
	371	return -ENOENT;
	372
	373	wait_on_page_writeback(page);
	374
	375	first_block = (unsigned long)index <<
09cbfeaf	376	(PAGE_SHIFT - inode->i_blkbits);
5eb563f5 RK	377	if (page_has_buffers(page)) {
	378	struct buffer_head *bh;
	379
	380	bh = nilfs_page_get_nth_block(page, block - first_block);
	381	nilfs_forget_buffer(bh);
	382	}
	383	still_dirty = PageDirty(page);
	384	unlock_page(page);
09cbfeaf	385	put_page(page);
5eb563f5 RK	386
	387	if (still_dirty \|\|
	388	invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
	389	ret = -EBUSY;
	390	return ret;
	391	}
	392
5eb563f5 RK	393	int nilfs_mdt_fetch_dirty(struct inode *inode)
	394	{
	395	struct nilfs_inode_info *ii = NILFS_I(inode);
	396
	397	if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
	398	set_bit(NILFS_I_DIRTY, &ii->i_state);
	399	return 1;
	400	}
	401	return test_bit(NILFS_I_DIRTY, &ii->i_state);
	402	}
	403
	404	static int
	405	nilfs_mdt_write_page(struct page page, struct writeback_control wbc)
	406	{
8c26c4e2	407	struct inode *inode = page->mapping->host;
ebdfed4d	408	struct super_block *sb;
5eb563f5 RK	409	int err = 0;
5eb563f5 RK	410
8c26c4e2 VD	411	if (inode && (inode->i_sb->s_flags & MS_RDONLY)) {
	412	/*
	413	* It means that filesystem was remounted in read-only
	414	* mode because of error or metadata corruption. But we
	415	* have dirty pages that try to be flushed in background.
	416	* So, here we simply discard this dirty page.
	417	*/
	418	nilfs_clear_dirty_page(page, false);
	419	unlock_page(page);
	420	return -EROFS;
	421	}
	422
5eb563f5 RK	423	redirty_page_for_writepage(wbc, page);
	424	unlock_page(page);
	425
ebdfed4d RK	426	if (!inode)
	427	return 0;
	428
	429	sb = inode->i_sb;
5eb563f5 RK	430
	431	if (wbc->sync_mode == WB_SYNC_ALL)
	432	err = nilfs_construct_segment(sb);
	433	else if (wbc->for_reclaim)
	434	nilfs_flush_segment(sb, inode->i_ino);
	435
5eb563f5 RK	436	return err;
	437	}
	438
	439
7f09410b	440	static const struct address_space_operations def_mdt_aops = {
5eb563f5 RK	441	.writepage = nilfs_mdt_write_page,
	442	};
	443
6e1d5dcc	444	static const struct inode_operations def_mdt_iops;
828c0950	445	static const struct file_operations def_mdt_fops;
5eb563f5	446
5e19a995	447
f1e89c86	448	int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
5e19a995 RK	449	{
	450	struct nilfs_mdt_info *mi;
	451
	452	mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
	453	if (!mi)
	454	return -ENOMEM;
	455
5e19a995 RK	456	init_rwsem(&mi->mi_sem);
	457	inode->i_private = mi;
	458
	459	inode->i_mode = S_IFREG;
	460	mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
f1e89c86 RK	461
	462	inode->i_op = &def_mdt_iops;
	463	inode->i_fop = &def_mdt_fops;
	464	inode->i_mapping->a_ops = &def_mdt_aops;
5e19a995 RK	465
	466	return 0;
	467	}
	468
2d19961d RK	469	/**
	470	* nilfs_mdt_clear - do cleanup for the metadata file
	471	* @inode: inode of the metadata file
	472	*/
	473	void nilfs_mdt_clear(struct inode *inode)
	474	{
	475	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
	476
	477	if (mdi->mi_palloc_cache)
	478	nilfs_palloc_destroy_cache(inode);
	479	}
	480
	481	/**
	482	* nilfs_mdt_destroy - release resources used by the metadata file
	483	* @inode: inode of the metadata file
	484	*/
	485	void nilfs_mdt_destroy(struct inode *inode)
	486	{
	487	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
	488
	489	kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
	490	kfree(mdi);
	491	}
	492
0c6c44cb RK	493	void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
0c6c44cb RK	494	unsigned int header_size)
5eb563f5 RK	495	{
	496	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	497
	498	mi->mi_entry_size = entry_size;
	499	mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
	500	mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
	501	}
	502
ebdfed4d RK	503	/**
	504	* nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
	505	* @inode: inode of the metadata file
	506	* @shadow: shadow mapping
	507	*/
	508	int nilfs_mdt_setup_shadow_map(struct inode *inode,
	509	struct nilfs_shadow_map *shadow)
	510	{
	511	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
ebdfed4d RK	512
ebdfed4d RK	513	INIT_LIST_HEAD(&shadow->frozen_buffers);
2aa15890	514	address_space_init_once(&shadow->frozen_data);
b83ae6d4	515	nilfs_mapping_init(&shadow->frozen_data, inode);
2aa15890	516	address_space_init_once(&shadow->frozen_btnodes);
b83ae6d4	517	nilfs_mapping_init(&shadow->frozen_btnodes, inode);
ebdfed4d RK	518	mi->mi_shadow = shadow;
	519	return 0;
	520	}
	521
	522	/**
	523	* nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
	524	* @inode: inode of the metadata file
	525	*/
	526	int nilfs_mdt_save_to_shadow_map(struct inode *inode)
	527	{
	528	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	529	struct nilfs_inode_info *ii = NILFS_I(inode);
	530	struct nilfs_shadow_map *shadow = mi->mi_shadow;
	531	int ret;
	532
	533	ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
	534	if (ret)
	535	goto out;
	536
	537	ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
	538	&ii->i_btnode_cache);
	539	if (ret)
	540	goto out;
	541
	542	nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
	543	out:
	544	return ret;
	545	}
	546
b1f6a4f2 RK	547	int nilfs_mdt_freeze_buffer(struct inode inode, struct buffer_head bh)
	548	{
	549	struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
	550	struct buffer_head *bh_frozen;
	551	struct page *page;
	552	int blkbits = inode->i_blkbits;
b1f6a4f2 RK	553
	554	page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
	555	if (!page)
a7a8447e	556	return -ENOMEM;
b1f6a4f2 RK	557
	558	if (!page_has_buffers(page))
	559	create_empty_buffers(page, 1 << blkbits, 0);
	560
	561	bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits);
a7a8447e RK	562
	563	if (!buffer_uptodate(bh_frozen))
	564	nilfs_copy_buffer(bh_frozen, bh);
	565	if (list_empty(&bh_frozen->b_assoc_buffers)) {
	566	list_add_tail(&bh_frozen->b_assoc_buffers,
	567	&shadow->frozen_buffers);
	568	set_buffer_nilfs_redirected(bh);
	569	} else {
	570	brelse(bh_frozen); /* already frozen */
b1f6a4f2	571	}
a7a8447e	572
b1f6a4f2	573	unlock_page(page);
09cbfeaf	574	put_page(page);
a7a8447e	575	return 0;
b1f6a4f2 RK	576	}
	577
	578	struct buffer_head *
	579	nilfs_mdt_get_frozen_buffer(struct inode inode, struct buffer_head bh)
	580	{
	581	struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
	582	struct buffer_head *bh_frozen = NULL;
	583	struct page *page;
	584	int n;
	585
	586	page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
	587	if (page) {
	588	if (page_has_buffers(page)) {
	589	n = bh_offset(bh) >> inode->i_blkbits;
	590	bh_frozen = nilfs_page_get_nth_block(page, n);
	591	}
	592	unlock_page(page);
09cbfeaf	593	put_page(page);
b1f6a4f2 RK	594	}
	595	return bh_frozen;
	596	}
	597
	598	static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
	599	{
	600	struct list_head *head = &shadow->frozen_buffers;
	601	struct buffer_head *bh;
	602
	603	while (!list_empty(head)) {
	604	bh = list_first_entry(head, struct buffer_head,
	605	b_assoc_buffers);
	606	list_del_init(&bh->b_assoc_buffers);
	607	brelse(bh); /* drop ref-count to make it releasable */
	608	}
	609	}
	610
ebdfed4d RK	611	/**
	612	* nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
	613	* @inode: inode of the metadata file
	614	*/
	615	void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
	616	{
	617	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	618	struct nilfs_inode_info *ii = NILFS_I(inode);
	619	struct nilfs_shadow_map *shadow = mi->mi_shadow;
	620
	621	down_write(&mi->mi_sem);
	622
	623	if (mi->mi_palloc_cache)
	624	nilfs_palloc_clear_cache(inode);
	625
8c26c4e2	626	nilfs_clear_dirty_pages(inode->i_mapping, true);
ebdfed4d RK	627	nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
ebdfed4d RK	628
8c26c4e2	629	nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
ebdfed4d RK	630	nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
	631
	632	nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
	633
	634	up_write(&mi->mi_sem);
	635	}
	636
	637	/**
	638	* nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
	639	* @inode: inode of the metadata file
	640	*/
	641	void nilfs_mdt_clear_shadow_map(struct inode *inode)
	642	{
	643	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
	644	struct nilfs_shadow_map *shadow = mi->mi_shadow;
	645
	646	down_write(&mi->mi_sem);
b1f6a4f2	647	nilfs_release_frozen_buffers(shadow);
ebdfed4d RK	648	truncate_inode_pages(&shadow->frozen_data, 0);
	649	truncate_inode_pages(&shadow->frozen_btnodes, 0);
	650	up_write(&mi->mi_sem);
	651	}