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Subject: Re: [f2fs-dev] [PATCH 1/4] f2fs: convert inline_dir early before
 starting rename
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20191218200947.20445-1-jaegeuk@kernel.org>
 <ed9a4733-9374-deae-8f70-d84a0ed686de@huawei.com>
 <20191231000645.GB77418@jaegeuk-macbookpro.roam.corp.google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <d4ea0c19-61da-8181-8fd9-62c3dfd42493@huawei.com>
Date:   Tue, 31 Dec 2019 09:22:36 +0800
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On 2019/12/31 8:06, Jaegeuk Kim wrote:
> On 12/28, Chao Yu wrote:
>> On 2019/12/19 4:09, Jaegeuk Kim wrote:
>>> If we hit an error during rename, we'll get two dentries in different
>>> directories.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
>>> ---
>>>  fs/f2fs/f2fs.h   |  1 +
>>>  fs/f2fs/inline.c | 30 ++++++++++++++++++++++++++++--
>>>  fs/f2fs/namei.c  | 36 +++++++++++++-----------------------
>>>  3 files changed, 42 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index dbc20d33d0e1..8d64525743cb 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -3490,6 +3490,7 @@ void f2fs_truncate_inline_inode(struct inode *inode,
>>>  int f2fs_read_inline_data(struct inode *inode, struct page *page);
>>>  int f2fs_convert_inline_page(struct dnode_of_data *dn, struct page *page);
>>>  int f2fs_convert_inline_inode(struct inode *inode);
>>> +int f2fs_convert_inline_dir(struct inode *dir);
>>>  int f2fs_write_inline_data(struct inode *inode, struct page *page);
>>>  bool f2fs_recover_inline_data(struct inode *inode, struct page *npage);
>>>  struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
>>> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
>>> index 52f85ed07a15..f82c3d9cf333 100644
>>> --- a/fs/f2fs/inline.c
>>> +++ b/fs/f2fs/inline.c
>>> @@ -530,7 +530,7 @@ static int f2fs_move_rehashed_dirents(struct inode *dir, struct page *ipage,
>>>  	return err;
>>>  }
>>>  
>>> -static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
>>> +static int do_convert_inline_dir(struct inode *dir, struct page *ipage,
>>>  							void *inline_dentry)
>>>  {
>>>  	if (!F2FS_I(dir)->i_dir_level)
>>> @@ -539,6 +539,32 @@ static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
>>>  		return f2fs_move_rehashed_dirents(dir, ipage, inline_dentry);
>>>  }
>>>  
>>> +int f2fs_convert_inline_dir(struct inode *dir)
>>> +{
>>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
>>> +	struct page *ipage;
>>> +	void *inline_dentry = NULL;
>>> +	int err;
>>> +
>>> +	if (!f2fs_has_inline_dentry(dir))
>>> +		return 0;
>>> +
>>> +	f2fs_lock_op(sbi);
>>> +
>>> +	ipage = f2fs_get_node_page(sbi, dir->i_ino);
>>> +	if (IS_ERR(ipage))
>>> +		return PTR_ERR(ipage);
>>> +
>>> +	inline_dentry = inline_data_addr(dir, ipage);
>>> +
>>> +	err = do_convert_inline_dir(dir, ipage, inline_dentry);
>>> +	if (!err)
>>> +		f2fs_put_page(ipage, 1);
>>> +
>>> +	f2fs_unlock_op(sbi);
>>> +	return err;
>>> +}
>>> +
>>>  int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
>>>  				const struct qstr *orig_name,
>>>  				struct inode *inode, nid_t ino, umode_t mode)
>>> @@ -562,7 +588,7 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *new_name,
>>>  
>>>  	bit_pos = f2fs_room_for_filename(d.bitmap, slots, d.max);
>>>  	if (bit_pos >= d.max) {
>>> -		err = f2fs_convert_inline_dir(dir, ipage, inline_dentry);
>>> +		err = do_convert_inline_dir(dir, ipage, inline_dentry);
>>>  		if (err)
>>>  			return err;
>>>  		err = -EAGAIN;
>>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>>> index 5d9584281935..61615ab466c2 100644
>>> --- a/fs/f2fs/namei.c
>>> +++ b/fs/f2fs/namei.c
>>> @@ -855,7 +855,6 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>  	struct f2fs_dir_entry *old_dir_entry = NULL;
>>>  	struct f2fs_dir_entry *old_entry;
>>>  	struct f2fs_dir_entry *new_entry;
>>> -	bool is_old_inline = f2fs_has_inline_dentry(old_dir);
>>>  	int err;
>>>  
>>>  	if (unlikely(f2fs_cp_error(sbi)))
>>> @@ -868,6 +867,19 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>  			F2FS_I(old_dentry->d_inode)->i_projid)))
>>>  		return -EXDEV;
>>>  
>>> +	/*
>>> +	 * old entry and new entry can locate in the same inline
>>> +	 * dentry in inode, when attaching new entry in inline dentry,
>>> +	 * it could force inline dentry conversion, after that,
>>> +	 * old_entry and old_page will point to wrong address, in
>>> +	 * order to avoid this, let's do the check and update here.
>>> +	 */
>>
>> The comment is out-of-update here...
>>
>> If there is enough room for the new dentry in old directory's inline space,
>> how about just keeping inline dir state for old directory?
> 
> It'd work, but how can we deal with race conditions?

In rename() syscall, both src/dst's parent inode lock should has been hold to
prevent race condition.

Thanks,

> 
>>
>>
>> ---
>>  fs/f2fs/dir.c    | 14 ++++++++++++++
>>  fs/f2fs/f2fs.h   |  4 +++-
>>  fs/f2fs/inline.c | 22 +++++++++++++++++-----
>>  fs/f2fs/namei.c  |  2 +-
>>  4 files changed, 35 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index c967cacf979e..b56f6060c1a6 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -578,6 +578,20 @@ int f2fs_room_for_filename(const void *bitmap, int slots, int max_slots)
>>  	goto next;
>>  }
>>
>> +bool f2fs_has_enough_room(struct inode *dir, struct page *ipage,
>> +					struct fscrypt_name *fname)
>> +{
>> +	struct f2fs_dentry_ptr d;
>> +	unsigned int bit_pos;
>> +	int slots = GET_DENTRY_SLOTS(fname_len(fname));
>> +
>> +	make_dentry_ptr_inline(dir, &d, inline_data_addr(dir, ipage));
>> +
>> +	bit_pos = f2fs_room_for_filename(d.bitmap, slots, d.max);
>> +
>> +	return bit_pos < d.max;
>> +}
>> +
>>  void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
>>  				const struct qstr *name, f2fs_hash_t name_hash,
>>  				unsigned int bit_pos)
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 5d55cef66410..ce4ce33a40ce 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -3120,6 +3120,8 @@ ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,
>>  			struct page **page);
>>  void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
>>  			struct page *page, struct inode *inode);
>> +bool f2fs_has_enough_room(struct inode *dir, struct page *ipage,
>> +					struct fscrypt_name *fname);
>>  void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d,
>>  			const struct qstr *name, f2fs_hash_t name_hash,
>>  			unsigned int bit_pos);
>> @@ -3662,7 +3664,7 @@ void f2fs_truncate_inline_inode(struct inode *inode,
>>  int f2fs_read_inline_data(struct inode *inode, struct page *page);
>>  int f2fs_convert_inline_page(struct dnode_of_data *dn, struct page *page);
>>  int f2fs_convert_inline_inode(struct inode *inode);
>> -int f2fs_convert_inline_dir(struct inode *dir);
>> +int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry);
>>  int f2fs_write_inline_data(struct inode *inode, struct page *page);
>>  bool f2fs_recover_inline_data(struct inode *inode, struct page *npage);
>>  struct f2fs_dir_entry *f2fs_find_in_inline_dir(struct inode *dir,
>> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
>> index f82c3d9cf333..4167e5408151 100644
>> --- a/fs/f2fs/inline.c
>> +++ b/fs/f2fs/inline.c
>> @@ -539,28 +539,40 @@ static int do_convert_inline_dir(struct inode *dir, struct page *ipage,
>>  		return f2fs_move_rehashed_dirents(dir, ipage, inline_dentry);
>>  }
>>
>> -int f2fs_convert_inline_dir(struct inode *dir)
>> +int f2fs_try_convert_inline_dir(struct inode *dir, struct dentry *dentry)
>>  {
>>  	struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
>>  	struct page *ipage;
>> +	struct fscrypt_name fname;
>>  	void *inline_dentry = NULL;
>> -	int err;
>> +	int err = 0;
>>
>>  	if (!f2fs_has_inline_dentry(dir))
>>  		return 0;
>>
>>  	f2fs_lock_op(sbi);
>>
>> +	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &fname);
>> +	if (err)
>> +		goto out;
>> +
>>  	ipage = f2fs_get_node_page(sbi, dir->i_ino);
>> -	if (IS_ERR(ipage))
>> -		return PTR_ERR(ipage);
>> +	if (IS_ERR(ipage)) {
>> +		err = PTR_ERR(ipage);
>> +		goto out;
>> +	}
>> +
>> +	if (f2fs_has_enough_room(dir, ipage, &fname)) {
>> +		f2fs_put_page(ipage, 1);
>> +		goto out;
>> +	}
>>
>>  	inline_dentry = inline_data_addr(dir, ipage);
>>
>>  	err = do_convert_inline_dir(dir, ipage, inline_dentry);
>>  	if (!err)
>>  		f2fs_put_page(ipage, 1);
>> -
>> +out:
>>  	f2fs_unlock_op(sbi);
>>  	return err;
>>  }
>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>> index 1daa54c8d8d8..856f0f984549 100644
>> --- a/fs/f2fs/namei.c
>> +++ b/fs/f2fs/namei.c
>> @@ -927,7 +927,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>  	 * order to avoid this, let's do the check and update here.
>>  	 */
>>  	if (old_dir == new_dir && !new_inode) {
>> -		err = f2fs_convert_inline_dir(old_dir);
>> +		err = f2fs_try_convert_inline_dir(old_dir, new_dentry);
>>  		if (err)
>>  			return err;
>>  	}
>> -- 
>> 2.18.0.rc1
>>
>> Thanks,
>>
>>> +	if (old_dir == new_dir && !new_inode) {
>>> +		err = f2fs_convert_inline_dir(old_dir);
>>> +		if (err)
>>> +			return err;
>>> +	}
>>> +
>>>  	if (flags & RENAME_WHITEOUT) {
>>>  		err = f2fs_create_whiteout(old_dir, &whiteout);
>>>  		if (err)
>>> @@ -954,28 +966,6 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>>  
>>>  		if (old_dir_entry)
>>>  			f2fs_i_links_write(new_dir, true);
>>> -
>>> -		/*
>>> -		 * old entry and new entry can locate in the same inline
>>> -		 * dentry in inode, when attaching new entry in inline dentry,
>>> -		 * it could force inline dentry conversion, after that,
>>> -		 * old_entry and old_page will point to wrong address, in
>>> -		 * order to avoid this, let's do the check and update here.
>>> -		 */
>>> -		if (is_old_inline && !f2fs_has_inline_dentry(old_dir)) {
>>> -			f2fs_put_page(old_page, 0);
>>> -			old_page = NULL;
>>> -
>>> -			old_entry = f2fs_find_entry(old_dir,
>>> -						&old_dentry->d_name, &old_page);
>>> -			if (!old_entry) {
>>> -				err = -ENOENT;
>>> -				if (IS_ERR(old_page))
>>> -					err = PTR_ERR(old_page);
>>> -				f2fs_unlock_op(sbi);
>>> -				goto out_dir;
>>> -			}
>>> -		}
>>>  	}
>>>  
>>>  	down_write(&F2FS_I(old_inode)->i_sem);
>>>
> .
>