Re: [PATCH v6 1/2] f2fs: fix to avoid broken of dnode block list
From: Jaegeuk Kim
Date: Wed Aug 01 2018 - 16:34:11 EST
On 07/29, 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.
>
> 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 <yuchao0@xxxxxxxxxx>
> ---
> 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.
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