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Date: Wed, 26 Sep 2018 16:31:57 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>
CC: <linux-kernel@...r.kernel.org>,
<linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH 2/2 v2] f2fs: avoid f2fs_bug_on if
f2fs_get_meta_page_nofail got EIO
On 2018/9/26 9:10, Chao Yu wrote:
> On 2018/9/26 8:18, Jaegeuk Kim wrote:
>> On 09/21, Chao Yu wrote:
>>> On 2018/9/21 5:46, Jaegeuk Kim wrote:
>>>> On 09/20, Chao Yu wrote:
>>>>> On 2018/9/19 1:56, Jaegeuk Kim wrote:
>>>>>> This patch avoids BUG_ON when f2fs_get_meta_page_nofail got EIO during
>>>>>> xfstests/generic/475.
>>>>>>
>>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>>>>> ---
>>>>>> Change log from v1:
>>>>>> - propagate errno
>>>>>> - drop sum_pages
>>>>>>
>>>>>> fs/f2fs/checkpoint.c | 10 +++++-----
>>>>>> fs/f2fs/f2fs.h | 2 +-
>>>>>> fs/f2fs/gc.c | 9 +++++++++
>>>>>> fs/f2fs/node.c | 32 ++++++++++++++++++++++++--------
>>>>>> fs/f2fs/recovery.c | 2 ++
>>>>>> fs/f2fs/segment.c | 3 +++
>>>>>> 6 files changed, 44 insertions(+), 14 deletions(-)
>>>>>>
>>>>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>>>>> index 01e0d8f5bbbe..1ddf332ce4b2 100644
>>>>>> --- a/fs/f2fs/checkpoint.c
>>>>>> +++ b/fs/f2fs/checkpoint.c
>>>>>> @@ -119,11 +119,8 @@ struct page *f2fs_get_meta_page_nofail(struct f2fs_sb_info *sbi, pgoff_t index)
>>>>>> if (PTR_ERR(page) == -EIO &&
>>>>>> ++count <= DEFAULT_RETRY_IO_COUNT)
>>>>>> goto retry;
>>>>>> -
>>>>>> f2fs_stop_checkpoint(sbi, false);
>>>>>> - f2fs_bug_on(sbi, 1);
>>>>>> }
>>>>>> -
>>>>>> return page;
>>>>>> }
>>>>>>
>>>>>> @@ -1512,7 +1509,10 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> ckpt->checkpoint_ver = cpu_to_le64(++ckpt_ver);
>>>>>>
>>>>>> /* write cached NAT/SIT entries to NAT/SIT area */
>>>>>> - f2fs_flush_nat_entries(sbi, cpc);
>>>>>> + err = f2fs_flush_nat_entries(sbi, cpc);
>>>>>> + if (err)
>>>>>> + goto stop;
>>>>>
>>>>> To make sure, if partial NAT pages become dirty, flush them back to device
>>>>> outside checkpoint() is not harmful, right?
>>>>
>>>> I think so.
>>>
>>> Oh, one more case, now we use NAT #0, if partial NAT pages were
>>> writebacked, then we start to use NAT #1, later, in another checkpoint(),
>>> we update those NAT pages again, we will write them to NAT #0, which is
>>> belong to last valid checkpoint(), it's may cause corrupted checkpoint in
>>> scenario of SPO. So it's harmfull, right?
>>
>> We already stopped checkpoint anymore, so there'd be no way to proceed another
>> checkpoint. Am I missing something?
>
> You're right, we have called f2fs_stop_checkpoint(), so we are safe now. :)
Can we allow to writeback fs metadata (NAT/SIT/SSA) in prior to checkpoint
to mitigate IO stress of checkpoint?
Maybe below conditions can be consider to trigger writebacking:
a) dirty count of meta (NAT/SIT/SSA) exceeds threshold
b) exceed time threshold
Thanks,
>
> Thanks,
>
>>
>>>
>>> Thanks,
>>>
>>>>
>>>>>
>>>>>> +
>>>>>> f2fs_flush_sit_entries(sbi, cpc);
>>>>>>
>>>>>> /* unlock all the fs_lock[] in do_checkpoint() */
>>>>>> @@ -1521,7 +1521,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> f2fs_release_discard_addrs(sbi);
>>>>>> else
>>>>>> f2fs_clear_prefree_segments(sbi, cpc);
>>>>>> -
>>>>>> +stop:
>>>>>> unblock_operations(sbi);
>>>>>> stat_inc_cp_count(sbi->stat_info);
>>>>>>
>>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>>>> index a0c868127a7c..29021dbc8f2a 100644
>>>>>> --- a/fs/f2fs/f2fs.h
>>>>>> +++ b/fs/f2fs/f2fs.h
>>>>>> @@ -2895,7 +2895,7 @@ int f2fs_recover_xattr_data(struct inode *inode, struct page *page);
>>>>>> int f2fs_recover_inode_page(struct f2fs_sb_info *sbi, struct page *page);
>>>>>> int f2fs_restore_node_summary(struct f2fs_sb_info *sbi,
>>>>>> unsigned int segno, struct f2fs_summary_block *sum);
>>>>>> -void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
>>>>>> +int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
>>>>>> int f2fs_build_node_manager(struct f2fs_sb_info *sbi);
>>>>>> void f2fs_destroy_node_manager(struct f2fs_sb_info *sbi);
>>>>>> int __init f2fs_create_node_manager_caches(void);
>>>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>>>>> index 4bcc8a59fdef..c7d14282dbf4 100644
>>>>>> --- a/fs/f2fs/gc.c
>>>>>> +++ b/fs/f2fs/gc.c
>>>>>> @@ -1070,6 +1070,15 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>>>>>> /* reference all summary page */
>>>>>> while (segno < end_segno) {
>>>>>> sum_page = f2fs_get_sum_page(sbi, segno++);
>>>>>> + if (IS_ERR(sum_page)) {
>>>>>> + end_segno = segno - 1;
>>>>>> + for (segno = start_segno; segno < end_segno; segno++) {
>>>>>> + sum_page = find_get_page(META_MAPPING(sbi),
>>>>>> + GET_SUM_BLOCK(sbi, segno));
>>>>>> + f2fs_put_page(sum_page, 0);
>>>>>
>>>>> find_get_page() will add one more reference on page, so we need to call
>>>>> f2fs_put_page(sum_page, 0) twice.
>>>>
>>>> Done.
>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>>> + }
>>>>>> + return PTR_ERR(sum_page);
>>>>>> + }
>>>>>> unlock_page(sum_page);
>>>>>> }
>>>>>>
>>>>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>>>>>> index fa2381c0bc47..79b6fee354f7 100644
>>>>>> --- a/fs/f2fs/node.c
>>>>>> +++ b/fs/f2fs/node.c
>>>>>> @@ -126,6 +126,8 @@ static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
>>>>>>
>>>>>> /* get current nat block page with lock */
>>>>>> src_page = get_current_nat_page(sbi, nid);
>>>>>> + if (IS_ERR(src_page))
>>>>>> + return src_page;
>>>>>> dst_page = f2fs_grab_meta_page(sbi, dst_off);
>>>>>> f2fs_bug_on(sbi, PageDirty(src_page));
>>>>>>
>>>>>> @@ -2265,15 +2267,19 @@ static int __f2fs_build_free_nids(struct f2fs_sb_info *sbi,
>>>>>> nm_i->nat_block_bitmap)) {
>>>>>> struct page *page = get_current_nat_page(sbi, nid);
>>>>>>
>>>>>> - ret = scan_nat_page(sbi, page, nid);
>>>>>> - f2fs_put_page(page, 1);
>>>>>> + if (IS_ERR(page)) {
>>>>>> + ret = PTR_ERR(page);
>>>>>> + } else {
>>>>>> + ret = scan_nat_page(sbi, page, nid);
>>>>>> + f2fs_put_page(page, 1);
>>>>>> + }
>>>>>>
>>>>>> if (ret) {
>>>>>> up_read(&nm_i->nat_tree_lock);
>>>>>> f2fs_bug_on(sbi, !mount);
>>>>>> f2fs_msg(sbi->sb, KERN_ERR,
>>>>>> "NAT is corrupt, run fsck to fix it");
>>>>>> - return -EINVAL;
>>>>>> + return ret;
>>>>>> }
>>>>>> }
>>>>>>
>>>>>> @@ -2700,7 +2706,7 @@ static void __update_nat_bits(struct f2fs_sb_info *sbi, nid_t start_nid,
>>>>>> __clear_bit_le(nat_index, nm_i->full_nat_bits);
>>>>>> }
>>>>>>
>>>>>> -static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>>>>>> +static int __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>>>>>> struct nat_entry_set *set, struct cp_control *cpc)
>>>>>> {
>>>>>> struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
>>>>>> @@ -2724,6 +2730,9 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>>>>>> down_write(&curseg->journal_rwsem);
>>>>>> } else {
>>>>>> page = get_next_nat_page(sbi, start_nid);
>>>>>> + if (IS_ERR(page))
>>>>>> + return PTR_ERR(page);
>>>>>> +
>>>>>> nat_blk = page_address(page);
>>>>>> f2fs_bug_on(sbi, !nat_blk);
>>>>>> }
>>>>>> @@ -2769,12 +2778,13 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
>>>>>> radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set);
>>>>>> kmem_cache_free(nat_entry_set_slab, set);
>>>>>> }
>>>>>> + return 0;
>>>>>> }
>>>>>>
>>>>>> /*
>>>>>> * This function is called during the checkpointing process.
>>>>>> */
>>>>>> -void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> +int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> {
>>>>>> struct f2fs_nm_info *nm_i = NM_I(sbi);
>>>>>> struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
>>>>>> @@ -2784,6 +2794,7 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> unsigned int found;
>>>>>> nid_t set_idx = 0;
>>>>>> LIST_HEAD(sets);
>>>>>> + int err = 0;
>>>>>>
>>>>>> /* during unmount, let's flush nat_bits before checking dirty_nat_cnt */
>>>>>> if (enabled_nat_bits(sbi, cpc)) {
>>>>>> @@ -2793,7 +2804,7 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> }
>>>>>>
>>>>>> if (!nm_i->dirty_nat_cnt)
>>>>>> - return;
>>>>>> + return 0;
>>>>>>
>>>>>> down_write(&nm_i->nat_tree_lock);
>>>>>>
>>>>>> @@ -2816,11 +2827,16 @@ void f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>>> }
>>>>>>
>>>>>> /* flush dirty nats in nat entry set */
>>>>>> - list_for_each_entry_safe(set, tmp, &sets, set_list)
>>>>>> - __flush_nat_entry_set(sbi, set, cpc);
>>>>>> + list_for_each_entry_safe(set, tmp, &sets, set_list) {
>>>>>> + err = __flush_nat_entry_set(sbi, set, cpc);
>>>>>> + if (err)
>>>>>> + break;
>>>>>> + }
>>>>>>
>>>>>> up_write(&nm_i->nat_tree_lock);
>>>>>> /* Allow dirty nats by node block allocation in write_begin */
>>>>>> +
>>>>>> + return err;
>>>>>> }
>>>>>>
>>>>>> static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
>>>>>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
>>>>>> index 56d34193a74b..ba678efe7cad 100644
>>>>>> --- a/fs/f2fs/recovery.c
>>>>>> +++ b/fs/f2fs/recovery.c
>>>>>> @@ -355,6 +355,8 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
>>>>>> }
>>>>>>
>>>>>> sum_page = f2fs_get_sum_page(sbi, segno);
>>>>>> + if (IS_ERR(sum_page))
>>>>>> + return PTR_ERR(sum_page);
>>>>>> sum_node = (struct f2fs_summary_block *)page_address(sum_page);
>>>>>> sum = sum_node->entries[blkoff];
>>>>>> f2fs_put_page(sum_page, 1);
>>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>>>>> index aa96a371aaf8..ab7386a7e9d3 100644
>>>>>> --- a/fs/f2fs/segment.c
>>>>>> +++ b/fs/f2fs/segment.c
>>>>>> @@ -2487,6 +2487,7 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type)
>>>>>> __next_free_blkoff(sbi, curseg, 0);
>>>>>>
>>>>>> sum_page = f2fs_get_sum_page(sbi, new_segno);
>>>>>> + f2fs_bug_on(sbi, IS_ERR(sum_page));
>>>>>> sum_node = (struct f2fs_summary_block *)page_address(sum_page);
>>>>>> memcpy(curseg->sum_blk, sum_node, SUM_ENTRY_SIZE);
>>>>>> f2fs_put_page(sum_page, 1);
>>>>>> @@ -3971,6 +3972,8 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
>>>>>>
>>>>>> se = &sit_i->sentries[start];
>>>>>> page = get_current_sit_page(sbi, start);
>>>>>> + if (IS_ERR(page))
>>>>>> + return PTR_ERR(page);
>>>>>> sit_blk = (struct f2fs_sit_block *)page_address(page);
>>>>>> sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)];
>>>>>> f2fs_put_page(page, 1);
>>>>>>
>>>>
>>>> .
>>>>
>>
>> .
>>
>
>
>
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>
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