Commit d624c96f authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: add recovery routines for roll-forward 



This adds roll-forward routines to recover fsynced data.

- F2FS uses basically roll-back model with checkpointing.

- In order to implement fsync(), there are two approaches as follows.

1. A roll-back model with checkpointing at every fsync()
 : This is a naive method, but suffers from very low performance.

2. A roll-forward model
 : F2FS adopts this model where all the fsynced data should be recovered, which
   were written after checkpointing was done. In order to figure out the data,
   F2FS keeps a "fsync" mark in direct node blocks. In addition, F2FS remains
   the location of next node block in each direct node block for reconstructing
   the chain of node blocks during the recovery.

- In order to enhance the performance, F2FS keeps a "dentry" mark also in direct
  node blocks. If this is set during the recovery, F2FS replays adding a dentry.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent 7bc09003

fs/f2fs/recovery.c

0 → 100644
+375 −0
Original line number Diff line number Diff line 
/**

 * fs/f2fs/recovery.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 "f2fs.h"

#include "node.h"

#include "segment.h"



static struct kmem_cache *fsync_entry_slab;



bool space_for_roll_forward(struct f2fs_sb_info *sbi)

{

	if (sbi->last_valid_block_count + sbi->alloc_valid_block_count

			> sbi->user_block_count)

		return false;

	return true;

}



static struct fsync_inode_entry *get_fsync_inode(struct list_head *head,

								nid_t ino)

{

	struct list_head *this;

	struct fsync_inode_entry *entry;



	list_for_each(this, head) {

		entry = list_entry(this, struct fsync_inode_entry, list);

		if (entry->inode->i_ino == ino)

			return entry;

	}

	return NULL;

}



static int recover_dentry(struct page *ipage, struct inode *inode)

{

	struct f2fs_node *raw_node = (struct f2fs_node *)kmap(ipage);

	struct f2fs_inode *raw_inode = &(raw_node->i);

	struct dentry dent, parent;

	struct f2fs_dir_entry *de;

	struct page *page;

	struct inode *dir;

	int err = 0;



	if (!is_dent_dnode(ipage))

		goto out;



	dir = f2fs_iget(inode->i_sb, le32_to_cpu(raw_inode->i_pino));

	if (IS_ERR(dir)) {

		err = -EINVAL;

		goto out;

	}



	parent.d_inode = dir;

	dent.d_parent = &parent;

	dent.d_name.len = le32_to_cpu(raw_inode->i_namelen);

	dent.d_name.name = raw_inode->i_name;



	de = f2fs_find_entry(dir, &dent.d_name, &page);

	if (de) {

		kunmap(page);

		f2fs_put_page(page, 0);

	} else {

		f2fs_add_link(&dent, inode);

	}

	iput(dir);

out:

	kunmap(ipage);

	return err;

}



static int recover_inode(struct inode *inode, struct page *node_page)

{

	void *kaddr = page_address(node_page);

	struct f2fs_node *raw_node = (struct f2fs_node *)kaddr;

	struct f2fs_inode *raw_inode = &(raw_node->i);



	inode->i_mode = le32_to_cpu(raw_inode->i_mode);

	i_size_write(inode, le64_to_cpu(raw_inode->i_size));

	inode->i_atime.tv_sec = le64_to_cpu(raw_inode->i_mtime);

	inode->i_ctime.tv_sec = le64_to_cpu(raw_inode->i_ctime);

	inode->i_mtime.tv_sec = le64_to_cpu(raw_inode->i_mtime);

	inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);

	inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec);

	inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);



	return recover_dentry(node_page, inode);

}



static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)

{

	unsigned long long cp_ver = le64_to_cpu(sbi->ckpt->checkpoint_ver);

	struct curseg_info *curseg;

	struct page *page;

	block_t blkaddr;

	int err = 0;



	/* get node pages in the current segment */

	curseg = CURSEG_I(sbi, CURSEG_WARM_NODE);

	blkaddr = START_BLOCK(sbi, curseg->segno) + curseg->next_blkoff;



	/* read node page */

	page = alloc_page(GFP_F2FS_ZERO);

	if (IS_ERR(page))

		return PTR_ERR(page);

	lock_page(page);



	while (1) {

		struct fsync_inode_entry *entry;



		if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))

			goto out;



		if (cp_ver != cpver_of_node(page))

			goto out;



		if (!is_fsync_dnode(page))

			goto next;



		entry = get_fsync_inode(head, ino_of_node(page));

		if (entry) {

			entry->blkaddr = blkaddr;

			if (IS_INODE(page) && is_dent_dnode(page))

				set_inode_flag(F2FS_I(entry->inode),

							FI_INC_LINK);

		} else {

			if (IS_INODE(page) && is_dent_dnode(page)) {

				if (recover_inode_page(sbi, page)) {

					err = -ENOMEM;

					goto out;

				}

			}



			/* add this fsync inode to the list */

			entry = kmem_cache_alloc(fsync_entry_slab, GFP_NOFS);

			if (!entry) {

				err = -ENOMEM;

				goto out;

			}



			INIT_LIST_HEAD(&entry->list);

			list_add_tail(&entry->list, head);



			entry->inode = f2fs_iget(sbi->sb, ino_of_node(page));

			if (IS_ERR(entry->inode)) {

				err = PTR_ERR(entry->inode);

				goto out;

			}

			entry->blkaddr = blkaddr;

		}

		if (IS_INODE(page)) {

			err = recover_inode(entry->inode, page);

			if (err)

				goto out;

		}

next:

		/* check next segment */

		blkaddr = next_blkaddr_of_node(page);

		ClearPageUptodate(page);

	}

out:

	unlock_page(page);

	__free_pages(page, 0);

	return err;

}



static void destroy_fsync_dnodes(struct f2fs_sb_info *sbi,

					struct list_head *head)

{

	struct list_head *this;

	struct fsync_inode_entry *entry;

	list_for_each(this, head) {

		entry = list_entry(this, struct fsync_inode_entry, list);

		iput(entry->inode);

		list_del(&entry->list);

		kmem_cache_free(fsync_entry_slab, entry);

	}

}



static void check_index_in_prev_nodes(struct f2fs_sb_info *sbi,

						block_t blkaddr)

{

	struct seg_entry *sentry;

	unsigned int segno = GET_SEGNO(sbi, blkaddr);

	unsigned short blkoff = GET_SEGOFF_FROM_SEG0(sbi, blkaddr) &

					(sbi->blocks_per_seg - 1);

	struct f2fs_summary sum;

	nid_t ino;

	void *kaddr;

	struct inode *inode;

	struct page *node_page;

	block_t bidx;

	int i;



	sentry = get_seg_entry(sbi, segno);

	if (!f2fs_test_bit(blkoff, sentry->cur_valid_map))

		return;



	/* Get the previous summary */

	for (i = CURSEG_WARM_DATA; i <= CURSEG_COLD_DATA; i++) {

		struct curseg_info *curseg = CURSEG_I(sbi, i);

		if (curseg->segno == segno) {

			sum = curseg->sum_blk->entries[blkoff];

			break;

		}

	}

	if (i > CURSEG_COLD_DATA) {

		struct page *sum_page = get_sum_page(sbi, segno);

		struct f2fs_summary_block *sum_node;

		kaddr = page_address(sum_page);

		sum_node = (struct f2fs_summary_block *)kaddr;

		sum = sum_node->entries[blkoff];

		f2fs_put_page(sum_page, 1);

	}



	/* Get the node page */

	node_page = get_node_page(sbi, le32_to_cpu(sum.nid));

	bidx = start_bidx_of_node(ofs_of_node(node_page)) +

				le16_to_cpu(sum.ofs_in_node);

	ino = ino_of_node(node_page);

	f2fs_put_page(node_page, 1);



	/* Deallocate previous index in the node page */

	inode = f2fs_iget_nowait(sbi->sb, ino);

	truncate_hole(inode, bidx, bidx + 1);

	iput(inode);

}



static void do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,

					struct page *page, block_t blkaddr)

{

	unsigned int start, end;

	struct dnode_of_data dn;

	struct f2fs_summary sum;

	struct node_info ni;



	start = start_bidx_of_node(ofs_of_node(page));

	if (IS_INODE(page))

		end = start + ADDRS_PER_INODE;

	else

		end = start + ADDRS_PER_BLOCK;



	set_new_dnode(&dn, inode, NULL, NULL, 0);

	if (get_dnode_of_data(&dn, start, 0))

		return;



	wait_on_page_writeback(dn.node_page);



	get_node_info(sbi, dn.nid, &ni);

	BUG_ON(ni.ino != ino_of_node(page));

	BUG_ON(ofs_of_node(dn.node_page) != ofs_of_node(page));



	for (; start < end; start++) {

		block_t src, dest;



		src = datablock_addr(dn.node_page, dn.ofs_in_node);

		dest = datablock_addr(page, dn.ofs_in_node);



		if (src != dest && dest != NEW_ADDR && dest != NULL_ADDR) {

			if (src == NULL_ADDR) {

				int err = reserve_new_block(&dn);

				/* We should not get -ENOSPC */

				BUG_ON(err);

			}



			/* Check the previous node page having this index */

			check_index_in_prev_nodes(sbi, dest);



			set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);



			/* write dummy data page */

			recover_data_page(sbi, NULL, &sum, src, dest);

			update_extent_cache(dest, &dn);

		}

		dn.ofs_in_node++;

	}



	/* write node page in place */

	set_summary(&sum, dn.nid, 0, 0);

	if (IS_INODE(dn.node_page))

		sync_inode_page(&dn);



	copy_node_footer(dn.node_page, page);

	fill_node_footer(dn.node_page, dn.nid, ni.ino,

					ofs_of_node(page), false);

	set_page_dirty(dn.node_page);



	recover_node_page(sbi, dn.node_page, &sum, &ni, blkaddr);

	f2fs_put_dnode(&dn);

}



static void recover_data(struct f2fs_sb_info *sbi,

				struct list_head *head, int type)

{

	unsigned long long cp_ver = le64_to_cpu(sbi->ckpt->checkpoint_ver);

	struct curseg_info *curseg;

	struct page *page;

	block_t blkaddr;



	/* get node pages in the current segment */

	curseg = CURSEG_I(sbi, type);

	blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);



	/* read node page */

	page = alloc_page(GFP_NOFS | __GFP_ZERO);

	if (IS_ERR(page))

		return;

	lock_page(page);



	while (1) {

		struct fsync_inode_entry *entry;



		if (f2fs_readpage(sbi, page, blkaddr, READ_SYNC))

			goto out;



		if (cp_ver != cpver_of_node(page))

			goto out;



		entry = get_fsync_inode(head, ino_of_node(page));

		if (!entry)

			goto next;



		do_recover_data(sbi, entry->inode, page, blkaddr);



		if (entry->blkaddr == blkaddr) {

			iput(entry->inode);

			list_del(&entry->list);

			kmem_cache_free(fsync_entry_slab, entry);

		}

next:

		/* check next segment */

		blkaddr = next_blkaddr_of_node(page);

		ClearPageUptodate(page);

	}

out:

	unlock_page(page);

	__free_pages(page, 0);



	allocate_new_segments(sbi);

}



void recover_fsync_data(struct f2fs_sb_info *sbi)

{

	struct list_head inode_list;



	fsync_entry_slab = f2fs_kmem_cache_create("f2fs_fsync_inode_entry",

			sizeof(struct fsync_inode_entry), NULL);

	if (unlikely(!fsync_entry_slab))

		return;



	INIT_LIST_HEAD(&inode_list);



	/* step #1: find fsynced inode numbers */

	if (find_fsync_dnodes(sbi, &inode_list))

		goto out;



	if (list_empty(&inode_list))

		goto out;



	/* step #2: recover data */

	sbi->por_doing = 1;

	recover_data(sbi, &inode_list, CURSEG_WARM_NODE);

	sbi->por_doing = 0;

	BUG_ON(!list_empty(&inode_list));

out:

	destroy_fsync_dnodes(sbi, &inode_list);

	kmem_cache_destroy(fsync_entry_slab);

	write_checkpoint(sbi, false, false);

}

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