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: Jaegeuk Kim <[email protected]>
---
fs/f2fs/recovery.c | 372 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 372 insertions(+)
create mode 100644 fs/f2fs/recovery.c
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
new file mode 100644
index 0000000..95455b1
--- /dev/null
+++ b/fs/f2fs/recovery.c
@@ -0,0 +1,372 @@
+/**
+ * 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 (!raw_node->footer.dentry)
+ 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 = le32_to_cpu(raw_inode->i_atime);
+ inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime);
+ inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime);
+
+ 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_NOFS | __GFP_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);
+}
--
1.7.9.5
---
Jaegeuk Kim
Samsung