On 2018/8/2 4:34, Jaegeuk Kim wrote:
> On 07/29, Chao Yu wrote:
>> From: Chao Yu <yuch...@huawei.com>
>>
>> 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.
>>
>> Sheng Yong helps to do the test with this patch:
>>
>> Target:/data (f2fs, -)
>> 64MB / 32768KB / 4KB / 8
>>
>> 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
>>
>> Patched/Original:
>>      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
>>
>> If we don't wait dnode writeback for atomic_write:
>>
>>      SEQ-RD(MB/s)    SEQ-WR(MB/s)    RND-RD(IOPS)    RND-WR(IOPS)    
>> Insert(TPS)     Update(TPS)     Delete(TPS)
>> 1    779.91          206.03          41621.5         40333.16        716.9   
>>         1038.21         1034.85
>> 2    848.51          204.35          40082.44        39486.17        791.83  
>>         1119.96         1083.77
>> 3    772.12          206.27          41335.25        41599.65        723.29  
>>         1055.07         971.92
>> Avg  800.18          205.55          41013.06333     40472.99333     
>> 744.0066667     1071.08         1030.18
>>
>> Patched/Original:
>>      0.92108464      1.001526693     0.987425886     0.993268102     
>> 1.030180511     1.026942031     0.976702294
>>
>> SQLite's performance recovers.
>>
>> Jaegeuk:
>> "Practically, I don't see db corruption becase of this. We can excuse to lose
>> the last transaction."
>>
>> Finally, we decide to keep original implementation of atomic write interface
>> sematics that we don't wait all dnode writeback before preflush+fua 
>> submission.
>>
>> Signed-off-by: Chao Yu <yuch...@huawei.com>
>> ---
>> v6:
>> - fix to wait all writeback pages in put_super() for cp_error case.
>>  fs/f2fs/checkpoint.c |   2 +
>>  fs/f2fs/data.c       |   2 +
>>  fs/f2fs/f2fs.h       |  21 ++++++-
>>  fs/f2fs/file.c       |   5 +-
>>  fs/f2fs/node.c       | 144 +++++++++++++++++++++++++++++++++++--------
>>  fs/f2fs/super.c      |   6 ++
>>  6 files changed, 152 insertions(+), 28 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 3587aa53dc90..896dc8c9702c 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -1418,6 +1418,8 @@ 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);
>> +
>>      clear_sbi_flag(sbi, SBI_IS_DIRTY);
>>      clear_sbi_flag(sbi, SBI_NEED_CP);
>>      __set_cp_next_pack(sbi);
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index eb994c66fe66..69bc00d90aae 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -177,6 +177,8 @@ static void f2fs_write_end_io(struct bio *bio)
>>                                      page->index != nid_of_node(page));
>>  
>>              dec_page_count(sbi, type);
>> +            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 a9447c7d6570..18dd13dd8782 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 */
>> @@ -1156,6 +1162,11 @@ 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 */
>>  
>> @@ -2827,6 +2838,10 @@ 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);
>> @@ -2836,7 +2851,8 @@ 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);
>> @@ -2845,7 +2861,8 @@ 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 bfe265d30da0..3f2c5863fab0 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;
>> @@ -301,7 +302,7 @@ static int f2fs_do_sync_file(struct file *file, loff_t 
>> start, loff_t end,
>>       * given fsync mark.
>>       */
>>      if (!atomic) {
>> -            ret = f2fs_wait_on_node_pages_writeback(sbi, ino);
>> +            ret = f2fs_wait_on_node_pages_writeback(sbi, seq_id);
>>              if (ret)
>>                      goto out;
>>      }
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index 6055d2d12640..78673736e453 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.
>> @@ -264,6 +265,72 @@ 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_seg_id = 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);
>> @@ -1384,7 +1451,7 @@ 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;
>> @@ -1401,6 +1468,7 @@ 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);
>>  
>> @@ -1446,6 +1514,13 @@ 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));
>> @@ -1493,7 +1568,7 @@ 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 {
>> @@ -1510,11 +1585,13 @@ 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;
>> @@ -1595,7 +1672,7 @@ 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);
>> @@ -1712,7 +1789,7 @@ 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)
>> @@ -1745,35 +1822,46 @@ 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;
>> +    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 ret2, ret = 0;
>> -    int nr_pages;
>>  
>> -    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;
>>  }
>>  
>> @@ -2988,8 +3076,15 @@ 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:
>> @@ -3000,6 +3095,7 @@ 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 5899d0cf1ab0..ee45a93a6ffd 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1036,6 +1036,10 @@ static void f2fs_put_super(struct super_block *sb)
>>      /* our cp_error case, we can wait for any writeback page */
>>      f2fs_flush_merged_writes(sbi);
>>  
>> +    wait_on_all_pages_writeback(sbi);
> 
> It's static function in checkpoint.c, resulting in a compilation error.
> I'll fix it and try fault injection test.

I've check in my private tree, it's already fixed, I guess I sent the wrong 
patch...

https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git/commit/?h=f2fs-dev&id=20387f1c42ead234a795057a8201e16324b6231c

Anyway, let me send v7.

Thanks,

> 
> Thanks,
> 
>> +
>> +    f2fs_bug_on(sbi, sbi->fsync_node_num);
>> +
>>      iput(sbi->node_inode);
>>      iput(sbi->meta_inode);
>>  
>> @@ -2923,6 +2927,8 @@ 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) {
>> -- 
>> 2.18.0

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