Re: [PATCH v3 1/2] f2fs: fix to avoid broken of dnode block list

From: Chao Yu
Date: Fri Jul 20 2018 - 06:45:21 EST

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Hi Jaegeuk,

On 2018/7/15 9:30, Chao Yu wrote:
> On 2018/7/14 13:44, Jaegeuk Kim wrote:
>> On 07/08, Chao Yu wrote:
>>> From: Chao Yu <yuchao0@xxxxxxxxxx>
>>>
>>> f2fs recovery flow is relying on dnode block link list, it means fsynced
>>> file recovery depends on previous dnode's persistence in the list, so
>>> during fsync() we should wait on all regular inode's dnode writebacked
>>> before issuing flush.
>>>
>>> By this way, we can avoid dnode block list being broken by out-of-order
>>> IO submission due to IO scheduler or driver.
>>
>> Hi Chao,
>>
>> Just in case, can we measure some performance numbers with this?
>
> Hi Jaegeuk,
>
> OK, let me do some tests on this.

Sheng Yong helps to do the test with this patch:

# Microbenchmark
Target:/data (f2fs, -)
64MB / 32768KB / 4KB / 8

# SQLite benchmark
1 / PERSIST / Index

Base:
SEQ-RD(MB/s) SEQ-WR(MB/s) RND-RD(IOPS) RND-WR(IOPS) Insert(TPS) Update(TPS) Delete(TPS)
1 867.82 204.15 41440.03 41370.54 680.8 1025.94 1031.08
2 871.87 205.87 41370.3 40275.2 791.14 1065.84 1101.7
3 866.52 205.69 41795.67 40596.16 694.69 1037.16 1031.48
Avg 868.7366667 205.2366667 41535.33333 40747.3 722.21 1042.98 1054.753333

After:
SEQ-RD(MB/s) SEQ-WR(MB/s) RND-RD(IOPS) RND-WR(IOPS) Insert(TPS) Update(TPS) Delete(TPS)
1 798.81 202.5 41143 40613.87 602.71 838.08 913.83
2 805.79 206.47 40297.2 41291.46 604.44 840.75 924.27
3 814.83 206.17 41209.57 40453.62 602.85 834.66 927.91
Avg 806.4766667 205.0466667 40883.25667 40786.31667 603.3333333 837.83 922.0033333

Orig/Patched:
0.928332713 0.999074239 0.984300676 1.000957528 0.835398753 0.803303994 0.874141189

It looks like atomic write will suffer performance regression.

I suspect that the criminal is that we forcing to wait all dnode being in
storage cache before we issue PREFLUSH+FUA.

BTW, will commit ("f2fs: don't need to wait for node writes for atomic write")
cause the problem: we will lose data of last transaction after SPO, even if
atomic write return no error:

- atomic_open();
- write() P1, P2, P3;
- atomic_commit();
- writeback data: P1, P2, P3;
- writeback node: N1, N2, N3; <--- If N1, N2 is not writebacked, N3 with fsync_mark is
writebacked, In SPOR, we won't find N3 since node chain is broken, turns out that losing
last transaction.
- preflush + fua;
- power-cut

Thanks,

>
> Thanks,
>
>>
>> Thanks,
>>
>>>
>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>> ---
>>> v3:
>>> - add a list to link all writebacked dnodes, let fsync() only wait on
>>> necessary dnode.
>>> fs/f2fs/checkpoint.c | 2 +
>>> fs/f2fs/data.c | 2 +
>>> fs/f2fs/f2fs.h | 21 +++++++-
>>> fs/f2fs/file.c | 20 +++----
>>> fs/f2fs/node.c | 148 +++++++++++++++++++++++++++++++++++++++++----------
>>> fs/f2fs/super.c | 4 ++
>>> 6 files changed, 153 insertions(+), 44 deletions(-)
>>>
>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>> index 8b698bd54490..d5e60d76362e 100644
>>> --- a/fs/f2fs/checkpoint.c
>>> +++ b/fs/f2fs/checkpoint.c
>>> @@ -1379,6 +1379,8 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>
>>> f2fs_release_ino_entry(sbi, false);
>>>
>>> + f2fs_reset_fsync_node_info(sbi);
>>> +
>>> if (unlikely(f2fs_cp_error(sbi)))
>>> return -EIO;
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 70813a4dda3e..afe76d87575c 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -176,6 +176,8 @@ static void f2fs_write_end_io(struct bio *bio)
>>> page->index != nid_of_node(page));
>>>
>>> dec_page_count(sbi, WB_DATA_TYPE(page));
>>> + if (f2fs_in_warm_node_list(sbi, page))
>>> + f2fs_del_fsync_node_entry(sbi, page);
>>> clear_cold_data(page);
>>> end_page_writeback(page);
>>> }
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index c8c865fa8450..bf5f7a336ace 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -228,6 +228,12 @@ struct inode_entry {
>>> struct inode *inode; /* vfs inode pointer */
>>> };
>>>
>>> +struct fsync_node_entry {
>>> + struct list_head list; /* list head */
>>> + struct page *page; /* warm node page pointer */
>>> + unsigned int seq_id; /* sequence id */
>>> +};
>>> +
>>> /* for the bitmap indicate blocks to be discarded */
>>> struct discard_entry {
>>> struct list_head list; /* list head */
>>> @@ -1152,6 +1158,11 @@ struct f2fs_sb_info {
>>>
>>> struct inode_management im[MAX_INO_ENTRY]; /* manage inode cache */
>>>
>>> + spinlock_t fsync_node_lock; /* for node entry lock */
>>> + struct list_head fsync_node_list; /* node list head */
>>> + unsigned int fsync_seg_id; /* sequence id */
>>> + unsigned int fsync_node_num; /* number of node entries */
>>> +
>>> /* for orphan inode, use 0'th array */
>>> unsigned int max_orphans; /* max orphan inodes */
>>>
>>> @@ -2816,6 +2827,10 @@ struct node_info;
>>>
>>> int f2fs_check_nid_range(struct f2fs_sb_info *sbi, nid_t nid);
>>> bool f2fs_available_free_memory(struct f2fs_sb_info *sbi, int type);
>>> +bool f2fs_in_warm_node_list(struct f2fs_sb_info *sbi, struct page *page);
>>> +void f2fs_init_fsync_node_info(struct f2fs_sb_info *sbi);
>>> +void f2fs_del_fsync_node_entry(struct f2fs_sb_info *sbi, struct page *page);
>>> +void f2fs_reset_fsync_node_info(struct f2fs_sb_info *sbi);
>>> int f2fs_need_dentry_mark(struct f2fs_sb_info *sbi, nid_t nid);
>>> bool f2fs_is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid);
>>> bool f2fs_need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino);
>>> @@ -2825,7 +2840,8 @@ pgoff_t f2fs_get_next_page_offset(struct dnode_of_data *dn, pgoff_t pgofs);
>>> int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode);
>>> int f2fs_truncate_inode_blocks(struct inode *inode, pgoff_t from);
>>> int f2fs_truncate_xattr_node(struct inode *inode);
>>> -int f2fs_wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino);
>>> +int f2fs_wait_on_node_pages_writeback(struct f2fs_sb_info *sbi,
>>> + unsigned int seq_id);
>>> int f2fs_remove_inode_page(struct inode *inode);
>>> struct page *f2fs_new_inode_page(struct inode *inode);
>>> struct page *f2fs_new_node_page(struct dnode_of_data *dn, unsigned int ofs);
>>> @@ -2834,7 +2850,8 @@ struct page *f2fs_get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid);
>>> struct page *f2fs_get_node_page_ra(struct page *parent, int start);
>>> void f2fs_move_node_page(struct page *node_page, int gc_type);
>>> int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
>>> - struct writeback_control *wbc, bool atomic);
>>> + struct writeback_control *wbc, bool atomic,
>>> + unsigned int *seq_id);
>>> int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
>>> struct writeback_control *wbc,
>>> bool do_balance, enum iostat_type io_type);
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 5e29d4053748..ddea2bfd4042 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -213,6 +213,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>>> .nr_to_write = LONG_MAX,
>>> .for_reclaim = 0,
>>> };
>>> + unsigned int seq_id = 0;
>>>
>>> if (unlikely(f2fs_readonly(inode->i_sb)))
>>> return 0;
>>> @@ -275,7 +276,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>>> }
>>> sync_nodes:
>>> atomic_inc(&sbi->wb_sync_req[NODE]);
>>> - ret = f2fs_fsync_node_pages(sbi, inode, &wbc, atomic);
>>> + ret = f2fs_fsync_node_pages(sbi, inode, &wbc, atomic, &seq_id);
>>> atomic_dec(&sbi->wb_sync_req[NODE]);
>>> if (ret)
>>> goto out;
>>> @@ -292,19 +293,10 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
>>> goto sync_nodes;
>>> }
>>>
>>> - /*
>>> - * If it's atomic_write, it's just fine to keep write ordering. So
>>> - * here we don't need to wait for node write completion, since we use
>>> - * node chain which serializes node blocks. If one of node writes are
>>> - * reordered, we can see simply broken chain, resulting in stopping
>>> - * roll-forward recovery. It means we'll recover all or none node blocks
>>> - * given fsync mark.
>>> - */
>>> - if (!atomic) {
>>> - ret = f2fs_wait_on_node_pages_writeback(sbi, ino);
>>> - if (ret)
>>> - goto out;
>>> - }
>>> +
>>> + ret = f2fs_wait_on_node_pages_writeback(sbi, seq_id);
>>> + if (ret)
>>> + goto out;
>>>
>>> /* once recovery info is written, don't need to tack this */
>>> f2fs_remove_ino_entry(sbi, ino, APPEND_INO);
>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>>> index 1e30bc305243..31dc372c56a0 100644
>>> --- a/fs/f2fs/node.c
>>> +++ b/fs/f2fs/node.c
>>> @@ -28,6 +28,7 @@
>>> static struct kmem_cache *nat_entry_slab;
>>> static struct kmem_cache *free_nid_slab;
>>> static struct kmem_cache *nat_entry_set_slab;
>>> +static struct kmem_cache *fsync_node_entry_slab;
>>>
>>> /*
>>> * Check whether the given nid is within node id range.
>>> @@ -267,6 +268,72 @@ static unsigned int __gang_lookup_nat_set(struct f2fs_nm_info *nm_i,
>>> start, nr);
>>> }
>>>
>>> +bool f2fs_in_warm_node_list(struct f2fs_sb_info *sbi, struct page *page)
>>> +{
>>> + return NODE_MAPPING(sbi) == page->mapping &&
>>> + IS_DNODE(page) && is_cold_node(page);
>>> +}
>>> +
>>> +void f2fs_init_fsync_node_info(struct f2fs_sb_info *sbi)
>>> +{
>>> + spin_lock_init(&sbi->fsync_node_lock);
>>> + INIT_LIST_HEAD(&sbi->fsync_node_list);
>>> + sbi->fsync_seg_id = 0;
>>> + sbi->fsync_node_num = 0;
>>> +}
>>> +
>>> +static unsigned int f2fs_add_fsync_node_entry(struct f2fs_sb_info *sbi,
>>> + struct page *page)
>>> +{
>>> + struct fsync_node_entry *fn;
>>> + unsigned long flags;
>>> + unsigned int seq_id;
>>> +
>>> + fn = f2fs_kmem_cache_alloc(fsync_node_entry_slab, GFP_NOFS);
>>> +
>>> + get_page(page);
>>> + fn->page = page;
>>> + INIT_LIST_HEAD(&fn->list);
>>> +
>>> + spin_lock_irqsave(&sbi->fsync_node_lock, flags);
>>> + list_add_tail(&fn->list, &sbi->fsync_node_list);
>>> + fn->seq_id = sbi->fsync_seg_id++;
>>> + seq_id = fn->seq_id;
>>> + sbi->fsync_node_num++;
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> +
>>> + return seq_id;
>>> +}
>>> +
>>> +void f2fs_del_fsync_node_entry(struct f2fs_sb_info *sbi, struct page *page)
>>> +{
>>> + struct fsync_node_entry *fn;
>>> + unsigned long flags;
>>> +
>>> + spin_lock_irqsave(&sbi->fsync_node_lock, flags);
>>> + list_for_each_entry(fn, &sbi->fsync_node_list, list) {
>>> + if (fn->page == page) {
>>> + list_del(&fn->list);
>>> + sbi->fsync_node_num--;
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> + kmem_cache_free(fsync_node_entry_slab, fn);
>>> + put_page(page);
>>> + return;
>>> + }
>>> + }
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> + f2fs_bug_on(sbi, 1);
>>> +}
>>> +
>>> +void f2fs_reset_fsync_node_info(struct f2fs_sb_info *sbi)
>>> +{
>>> + unsigned long flags;
>>> +
>>> + spin_lock_irqsave(&sbi->fsync_node_lock, flags);
>>> + sbi->fsync_node_num = 0;
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> +}
>>> +
>>> int f2fs_need_dentry_mark(struct f2fs_sb_info *sbi, nid_t nid)
>>> {
>>> struct f2fs_nm_info *nm_i = NM_I(sbi);
>>> @@ -1353,7 +1420,7 @@ static struct page *last_fsync_dnode(struct f2fs_sb_info *sbi, nid_t ino)
>>>
>>> static int __write_node_page(struct page *page, bool atomic, bool *submitted,
>>> struct writeback_control *wbc, bool do_balance,
>>> - enum iostat_type io_type)
>>> + enum iostat_type io_type, unsigned int *seq_id)
>>> {
>>> struct f2fs_sb_info *sbi = F2FS_P_SB(page);
>>> nid_t nid;
>>> @@ -1370,6 +1437,7 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
>>> .io_type = io_type,
>>> .io_wbc = wbc,
>>> };
>>> + unsigned int seq;
>>>
>>> trace_f2fs_writepage(page, NODE);
>>>
>>> @@ -1416,6 +1484,13 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
>>>
>>> set_page_writeback(page);
>>> ClearPageError(page);
>>> +
>>> + if (f2fs_in_warm_node_list(sbi, page)) {
>>> + seq = f2fs_add_fsync_node_entry(sbi, page);
>>> + if (seq_id)
>>> + *seq_id = seq;
>>> + }
>>> +
>>> fio.old_blkaddr = ni.blk_addr;
>>> f2fs_do_write_node_page(nid, &fio);
>>> set_node_addr(sbi, &ni, fio.new_blkaddr, is_fsync_dnode(page));
>>> @@ -1463,7 +1538,7 @@ void f2fs_move_node_page(struct page *node_page, int gc_type)
>>> goto out_page;
>>>
>>> if (__write_node_page(node_page, false, NULL,
>>> - &wbc, false, FS_GC_NODE_IO))
>>> + &wbc, false, FS_GC_NODE_IO, NULL))
>>> unlock_page(node_page);
>>> goto release_page;
>>> } else {
>>> @@ -1480,11 +1555,13 @@ void f2fs_move_node_page(struct page *node_page, int gc_type)
>>> static int f2fs_write_node_page(struct page *page,
>>> struct writeback_control *wbc)
>>> {
>>> - return __write_node_page(page, false, NULL, wbc, false, FS_NODE_IO);
>>> + return __write_node_page(page, false, NULL, wbc, false,
>>> + FS_NODE_IO, NULL);
>>> }
>>>
>>> int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
>>> - struct writeback_control *wbc, bool atomic)
>>> + struct writeback_control *wbc, bool atomic,
>>> + unsigned int *seq_id)
>>> {
>>> pgoff_t index;
>>> pgoff_t last_idx = ULONG_MAX;
>>> @@ -1565,7 +1642,7 @@ int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
>>> ret = __write_node_page(page, atomic &&
>>> page == last_page,
>>> &submitted, wbc, true,
>>> - FS_NODE_IO);
>>> + FS_NODE_IO, seq_id);
>>> if (ret) {
>>> unlock_page(page);
>>> f2fs_put_page(last_page, 0);
>>> @@ -1682,7 +1759,7 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
>>> set_dentry_mark(page, 0);
>>>
>>> ret = __write_node_page(page, false, &submitted,
>>> - wbc, do_balance, io_type);
>>> + wbc, do_balance, io_type, NULL);
>>> if (ret)
>>> unlock_page(page);
>>> else if (submitted)
>>> @@ -1713,35 +1790,42 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
>>> return ret;
>>> }
>>>
>>> -int f2fs_wait_on_node_pages_writeback(struct f2fs_sb_info *sbi, nid_t ino)
>>> +int f2fs_wait_on_node_pages_writeback(struct f2fs_sb_info *sbi,
>>> + unsigned int seq_id)
>>> {
>>> - pgoff_t index = 0;
>>> - struct pagevec pvec;
>>> - int ret2, ret = 0;
>>> - int nr_pages;
>>> + struct fsync_node_entry *fn;
>>> + struct page *page;
>>> + struct list_head *head = &sbi->fsync_node_list;
>>> + unsigned long flags;
>>> + unsigned int cur_seq_id = 0;
>>> + int ret = 0;
>>>
>>> - pagevec_init(&pvec);
>>> + while (seq_id && cur_seq_id < seq_id) {
>>> + spin_lock_irqsave(&sbi->fsync_node_lock, flags);
>>> + if (list_empty(head)) {
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> + break;
>>> + }
>>> + fn = list_first_entry(head, struct fsync_node_entry, list);
>>> + if (fn->seq_id > seq_id) {
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>> + break;
>>> + }
>>> + cur_seq_id = fn->seq_id;
>>> + page = fn->page;
>>> + get_page(page);
>>> + spin_unlock_irqrestore(&sbi->fsync_node_lock, flags);
>>>
>>> - while ((nr_pages = pagevec_lookup_tag(&pvec, NODE_MAPPING(sbi), &index,
>>> - PAGECACHE_TAG_WRITEBACK))) {
>>> - int i;
>>> + f2fs_wait_on_page_writeback(page, NODE, true);
>>> + if (TestClearPageError(page))
>>> + ret = -EIO;
>>>
>>> - for (i = 0; i < nr_pages; i++) {
>>> - struct page *page = pvec.pages[i];
>>> + put_page(page);
>>>
>>> - if (ino && ino_of_node(page) == ino) {
>>> - f2fs_wait_on_page_writeback(page, NODE, true);
>>> - if (TestClearPageError(page))
>>> - ret = -EIO;
>>> - }
>>> - }
>>> - pagevec_release(&pvec);
>>> - cond_resched();
>>> + if (ret)
>>> + break;
>>> }
>>>
>>> - ret2 = filemap_check_errors(NODE_MAPPING(sbi));
>>> - if (!ret)
>>> - ret = ret2;
>>> return ret;
>>> }
>>>
>>> @@ -2939,8 +3023,15 @@ int __init f2fs_create_node_manager_caches(void)
>>> sizeof(struct nat_entry_set));
>>> if (!nat_entry_set_slab)
>>> goto destroy_free_nid;
>>> +
>>> + fsync_node_entry_slab = f2fs_kmem_cache_create("fsync_node_entry",
>>> + sizeof(struct fsync_node_entry));
>>> + if (!fsync_node_entry_slab)
>>> + goto destroy_nat_entry_set;
>>> return 0;
>>>
>>> +destroy_nat_entry_set:
>>> + kmem_cache_destroy(nat_entry_set_slab);
>>> destroy_free_nid:
>>> kmem_cache_destroy(free_nid_slab);
>>> destroy_nat_entry:
>>> @@ -2951,6 +3042,7 @@ int __init f2fs_create_node_manager_caches(void)
>>>
>>> void f2fs_destroy_node_manager_caches(void)
>>> {
>>> + kmem_cache_destroy(fsync_node_entry_slab);
>>> kmem_cache_destroy(nat_entry_set_slab);
>>> kmem_cache_destroy(free_nid_slab);
>>> kmem_cache_destroy(nat_entry_slab);
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 143ed321076e..34321932754d 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -1023,6 +1023,8 @@ static void f2fs_put_super(struct super_block *sb)
>>> */
>>> f2fs_release_ino_entry(sbi, true);
>>>
>>> + f2fs_bug_on(sbi, sbi->fsync_node_num);
>>> +
>>> f2fs_leave_shrinker(sbi);
>>> mutex_unlock(&sbi->umount_mutex);
>>>
>>> @@ -2903,6 +2905,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>>>
>>> f2fs_init_ino_entry_info(sbi);
>>>
>>> + f2fs_init_fsync_node_info(sbi);
>>> +
>>> /* setup f2fs internal modules */
>>> err = f2fs_build_segment_manager(sbi);
>>> if (err) {
>>> --
>>> 2.16.2.17.g38e79b1fd
>
> .
>

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