Re: [PATCH v5 1/2] f2fs: fix to avoid broken of dnode block list
From: Chao Yu
Date: Sat Jul 28 2018 - 22:10:25 EST
On 2018/7/29 9:33, Jaegeuk Kim wrote:
> On 07/28, Chao Yu wrote:
>> 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
>
> I expect Sheng will provide more test results tho, at least it seems SEQ-RD
> in Base shows better than two After results, even if it doesn't matter with
> the issue. Please confirm it first in order for anybody to say there is no
> regression.
Agreed.
Thanks,
>
>>
>> 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.
>>
>> Tested-by: Sheng Yong <shengyong1@xxxxxxxxxx>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> ---
>> v5:
>> - add missing Tested-by.
>> - fix f2fs_reset_fsync_node_info() to reset sbi->fsync_seg_id correctly.
>> 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 | 4 ++
>> 6 files changed, 150 insertions(+), 28 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 581710760ba6..2136430f9f0d 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -1410,6 +1410,8 @@ 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 6b8ca5011bfd..572c91e43337 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 0374f069520c..6627fef9ae38 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 */
>>
>> @@ -2822,6 +2833,10 @@ 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);
>> @@ -2831,7 +2846,8 @@ 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);
>> @@ -2840,7 +2856,8 @@ 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 8f9ab66858ca..7bd2412a8c37 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 9d9f4c9750c4..e109c671cd84 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);
>>
>> @@ -1442,6 +1510,13 @@ 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));
>> @@ -1489,7 +1564,7 @@ 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 {
>> @@ -1506,11 +1581,13 @@ 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;
>> @@ -1591,7 +1668,7 @@ 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);
>> @@ -1708,7 +1785,7 @@ 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)
>> @@ -1739,35 +1816,46 @@ 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;
>> }
>>
>> @@ -2982,8 +3070,15 @@ 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:
>> @@ -2994,6 +3089,7 @@ 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 0eff4637fe55..cb1ba9f18353 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -1030,6 +1030,8 @@ 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);
>>
>> @@ -2923,6 +2925,8 @@ 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.rc1