Re: [PATCH 1/5] f2fs: fix to wait page writeback before update

From: Chao Yu
Date: Fri Jun 19 2020 - 02:44:45 EST


On 2020/6/19 13:49, Jaegeuk Kim wrote:
> On 06/19, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> On 2020/6/19 7:59, Jaegeuk Kim wrote:
>>> Hi Chao,
>>>
>>> On 06/18, Chao Yu wrote:
>>>> to make page content stable for special device like raid.
>>>
>>> Could you elaborate the problem a bit?
>>
>> Some devices like raid5 wants page content to be stable, because
>> it will calculate parity info based page content, if page is not
>> stable, parity info could be corrupted, result in data inconsistency
>> in stripe.
>
> I don't get the point, since those pages are brand new pages which were not
> modified before. If it's on writeback, we should not modify them regardless
> of whatever raid configuration. For example, f2fs_new_node_page() waits for
> writeback. Am I missing something?

I think we should use f2fs_bug_on(, PageWriteback()) rather than
f2fs_wait_on_page_writeback() for brand new page which is allocated just now.
For other paths, we can keep rule that waiting for writeback before updating.

How do you think?

Thanks,

>
>>
>> Thanks,
>>
>>>
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>>> ---
>>>> fs/f2fs/dir.c | 2 ++
>>>> fs/f2fs/extent_cache.c | 18 +++++++++---------
>>>> fs/f2fs/f2fs.h | 2 +-
>>>> fs/f2fs/file.c | 1 +
>>>> fs/f2fs/inline.c | 2 ++
>>>> fs/f2fs/inode.c | 3 +--
>>>> 6 files changed, 16 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>>>> index d35976785e8c..91e86747a604 100644
>>>> --- a/fs/f2fs/dir.c
>>>> +++ b/fs/f2fs/dir.c
>>>> @@ -495,6 +495,8 @@ static int make_empty_dir(struct inode *inode,
>>>> if (IS_ERR(dentry_page))
>>>> return PTR_ERR(dentry_page);
>>>>
>>>> + f2fs_bug_on(F2FS_I_SB(inode), PageWriteback(dentry_page));
>>>> +
>>>> dentry_blk = page_address(dentry_page);
>>>>
>>>> make_dentry_ptr_block(NULL, &d, dentry_blk);
>>>> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
>>>> index e60078460ad1..686c68b98610 100644
>>>> --- a/fs/f2fs/extent_cache.c
>>>> +++ b/fs/f2fs/extent_cache.c
>>>> @@ -325,9 +325,10 @@ static void __drop_largest_extent(struct extent_tree *et,
>>>> }
>>>>
>>>> /* return true, if inode page is changed */
>>>> -static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
>>>> +static void __f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
>>>> {
>>>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>> + struct f2fs_extent *i_ext = ipage ? &F2FS_INODE(ipage)->i_ext : NULL;
>>>> struct extent_tree *et;
>>>> struct extent_node *en;
>>>> struct extent_info ei;
>>>> @@ -335,16 +336,18 @@ static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_e
>>>> if (!f2fs_may_extent_tree(inode)) {
>>>> /* drop largest extent */
>>>> if (i_ext && i_ext->len) {
>>>> + f2fs_wait_on_page_writeback(ipage, NODE, true, true);
>>>> i_ext->len = 0;
>>>> - return true;
>>>> + set_page_dirty(ipage);
>>>> + return;
>>>> }
>>>> - return false;
>>>> + return;
>>>> }
>>>>
>>>> et = __grab_extent_tree(inode);
>>>>
>>>> if (!i_ext || !i_ext->len)
>>>> - return false;
>>>> + return;
>>>>
>>>> get_extent_info(&ei, i_ext);
>>>>
>>>> @@ -360,17 +363,14 @@ static bool __f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_e
>>>> }
>>>> out:
>>>> write_unlock(&et->lock);
>>>> - return false;
>>>> }
>>>>
>>>> -bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
>>>> +void f2fs_init_extent_tree(struct inode *inode, struct page *ipage)
>>>> {
>>>> - bool ret = __f2fs_init_extent_tree(inode, i_ext);
>>>> + __f2fs_init_extent_tree(inode, ipage);
>>>>
>>>> if (!F2FS_I(inode)->extent_tree)
>>>> set_inode_flag(inode, FI_NO_EXTENT);
>>>> -
>>>> - return ret;
>>>> }
>>>>
>>>> static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index b35a50f4953c..326c12fa0da5 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -3795,7 +3795,7 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
>>>> bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
>>>> struct rb_root_cached *root);
>>>> unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink);
>>>> -bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext);
>>>> +void f2fs_init_extent_tree(struct inode *inode, struct page *ipage);
>>>> void f2fs_drop_extent_tree(struct inode *inode);
>>>> unsigned int f2fs_destroy_extent_node(struct inode *inode);
>>>> void f2fs_destroy_extent_tree(struct inode *inode);
>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>> index 3268f8dd59bb..1862073b96d2 100644
>>>> --- a/fs/f2fs/file.c
>>>> +++ b/fs/f2fs/file.c
>>>> @@ -1250,6 +1250,7 @@ static int __clone_blkaddrs(struct inode *src_inode, struct inode *dst_inode,
>>>> f2fs_put_page(psrc, 1);
>>>> return PTR_ERR(pdst);
>>>> }
>>>> + f2fs_wait_on_page_writeback(pdst, DATA, true, true);
>>>> f2fs_copy_page(psrc, pdst);
>>>> set_page_dirty(pdst);
>>>> f2fs_put_page(pdst, 1);
>>>> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
>>>> index dbade310dc79..4bcbc486c9e2 100644
>>>> --- a/fs/f2fs/inline.c
>>>> +++ b/fs/f2fs/inline.c
>>>> @@ -340,6 +340,8 @@ int f2fs_make_empty_inline_dir(struct inode *inode, struct inode *parent,
>>>> struct f2fs_dentry_ptr d;
>>>> void *inline_dentry;
>>>>
>>>> + f2fs_wait_on_page_writeback(ipage, NODE, true, true);
>>>> +
>>>> inline_dentry = inline_data_addr(inode, ipage);
>>>>
>>>> make_dentry_ptr_inline(inode, &d, inline_dentry);
>>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>>> index 44582a4db513..7c156eb26dd7 100644
>>>> --- a/fs/f2fs/inode.c
>>>> +++ b/fs/f2fs/inode.c
>>>> @@ -367,8 +367,7 @@ static int do_read_inode(struct inode *inode)
>>>> fi->i_pino = le32_to_cpu(ri->i_pino);
>>>> fi->i_dir_level = ri->i_dir_level;
>>>>
>>>> - if (f2fs_init_extent_tree(inode, &ri->i_ext))
>>>> - set_page_dirty(node_page);
>>>> + f2fs_init_extent_tree(inode, node_page);
>>>>
>>>> get_inline_info(inode, ri);
>>>>
>>>> --
>>>> 2.18.0.rc1
>>> .
>>>
> .
>