Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>
References: <20200227112621.126505-1-yuchao0@huawei.com>
 <20200227183052.GA55284@google.com>
 <8cb4552e-e6a2-e57b-1baa-40171e53e120@huawei.com>
 <20200304182635.GA87370@google.com> <20200305002950.GA193721@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <23e51691-7201-11d8-0b11-82614a1dfcfc@huawei.com>
Date:   Thu, 5 Mar 2020 14:34:17 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <20200305002950.GA193721@google.com>
Content-Type: text/plain; charset="windows-1252"
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2020/3/5 8:29, Jaegeuk Kim wrote:
> On 03/04, Jaegeuk Kim wrote:
>> On 02/28, Chao Yu wrote:
>>> On 2020/2/28 2:30, Jaegeuk Kim wrote:
>>>> On 02/27, Chao Yu wrote:
>>>>> There are still reserved blocks on compressed inode, this patch
>>>>> introduce a new ioctl to help release reserved blocks back to
>>>>> filesystem, so that userspace can reuse those freed space.
> 
> BTW, this patch makes i_blocks breakages. Could you please check?

It's consistent, however we should not account COMPRESS_ADDR as reserved
block once we released compress block on that inode:

		if (blkaddr == COMPRESS_ADDR) {
			fsck->chk.valid_blk_cnt++;
			*blk_cnt = *blk_cnt + 1;
			continue;
		}

Thanks,

> 
>>>>
>>>> Hmm, once we release the blocks, what happens if we remove the immutable
>>>> bit back?
>>>
>>> Oh, if we allow to overwrite on compress file, i_blocks and real physical blocks
>>> usage may be inconsistent?
>>>
>>> So if we need to support above scenario, should we add another ioctl interface
>>> to rollback all compress inode status:
>>> - add reserved blocks in dnode blocks
>>> - increase i_compr_blocks, i_blocks, total_valid_block_count
>>> - remove immutable
>>
>> I think that'd be doable.
>>
>>>
>>> Thanks,
>>>
>>>>
>>>>>
>>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>>> ---
>>>>> v2:
>>>>> - set inode as immutable in ioctl.
>>>>>  fs/f2fs/f2fs.h |   6 +++
>>>>>  fs/f2fs/file.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++-
>>>>>  2 files changed, 141 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>>> index 23b93a116c73..4a02edc2454b 100644
>>>>> --- a/fs/f2fs/f2fs.h
>>>>> +++ b/fs/f2fs/f2fs.h
>>>>> @@ -427,6 +427,8 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
>>>>>  #define F2FS_IOC_PRECACHE_EXTENTS	_IO(F2FS_IOCTL_MAGIC, 15)
>>>>>  #define F2FS_IOC_RESIZE_FS		_IOW(F2FS_IOCTL_MAGIC, 16, __u64)
>>>>>  #define F2FS_IOC_GET_COMPRESS_BLOCKS	_IOR(F2FS_IOCTL_MAGIC, 17, __u64)
>>>>> +#define F2FS_IOC_RELEASE_COMPRESS_BLOCKS				\
>>>>> +					_IOR(F2FS_IOCTL_MAGIC, 18, __u64)
>>>>>  
>>>>>  #define F2FS_IOC_GET_VOLUME_NAME	FS_IOC_GETFSLABEL
>>>>>  #define F2FS_IOC_SET_VOLUME_NAME	FS_IOC_SETFSLABEL
>>>>> @@ -3956,6 +3958,10 @@ static inline void f2fs_i_compr_blocks_update(struct inode *inode,
>>>>>  {
>>>>>  	int diff = F2FS_I(inode)->i_cluster_size - blocks;
>>>>>  
>>>>> +	/* don't update i_compr_blocks if saved blocks were released */
>>>>> +	if (!add && !F2FS_I(inode)->i_compr_blocks)
>>>>> +		return;
>>>>> +
>>>>>  	if (add) {
>>>>>  		F2FS_I(inode)->i_compr_blocks += diff;
>>>>>  		stat_add_compr_blocks(inode, diff);
>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>>>> index 37c1147eb244..b8f01ee9d698 100644
>>>>> --- a/fs/f2fs/file.c
>>>>> +++ b/fs/f2fs/file.c
>>>>> @@ -550,6 +550,7 @@ void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)
>>>>>  	bool compressed_cluster = false;
>>>>>  	int cluster_index = 0, valid_blocks = 0;
>>>>>  	int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
>>>>> +	bool released = !F2FS_I(dn->inode)->i_compr_blocks;
>>>>>  
>>>>>  	if (IS_INODE(dn->node_page) && f2fs_has_extra_attr(dn->inode))
>>>>>  		base = get_extra_isize(dn->inode);
>>>>> @@ -588,7 +589,9 @@ void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)
>>>>>  			clear_inode_flag(dn->inode, FI_FIRST_BLOCK_WRITTEN);
>>>>>  
>>>>>  		f2fs_invalidate_blocks(sbi, blkaddr);
>>>>> -		nr_free++;
>>>>> +
>>>>> +		if (released && blkaddr != COMPRESS_ADDR)
>>>>> +			nr_free++;
>>>>>  	}
>>>>>  
>>>>>  	if (compressed_cluster)
>>>>> @@ -3403,6 +3406,134 @@ static int f2fs_get_compress_blocks(struct file *filp, unsigned long arg)
>>>>>  	return put_user(blocks, (u64 __user *)arg);
>>>>>  }
>>>>>  
>>>>> +static int release_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
>>>>> +{
>>>>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
>>>>> +	unsigned int released_blocks = 0;
>>>>> +	int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
>>>>> +
>>>>> +	while (count) {
>>>>> +		int compr_blocks = 0;
>>>>> +		block_t blkaddr = f2fs_data_blkaddr(dn);
>>>>> +		int i;
>>>>> +
>>>>> +		if (blkaddr != COMPRESS_ADDR) {
>>>>> +			dn->ofs_in_node += cluster_size;
>>>>> +			goto next;
>>>>> +		}
>>>>> +
>>>>> +		for (i = 0; i < cluster_size; i++, dn->ofs_in_node++) {
>>>>> +			blkaddr = f2fs_data_blkaddr(dn);
>>>>> +
>>>>> +			if (__is_valid_data_blkaddr(blkaddr)) {
>>>>> +				compr_blocks++;
>>>>> +				if (unlikely(!f2fs_is_valid_blkaddr(sbi, blkaddr,
>>>>> +							DATA_GENERIC_ENHANCE)))
>>>>> +					return -EFSCORRUPTED;
>>>>> +			}
>>>>> +
>>>>> +			if (blkaddr != NEW_ADDR)
>>>>> +				continue;
>>>>> +
>>>>> +			dn->data_blkaddr = NULL_ADDR;
>>>>> +			f2fs_set_data_blkaddr(dn);
>>>>> +		}
>>>>> +
>>>>> +		f2fs_i_compr_blocks_update(dn->inode, compr_blocks, false);
>>>>> +		dec_valid_block_count(sbi, dn->inode,
>>>>> +					cluster_size - compr_blocks);
>>>>> +
>>>>> +		released_blocks += cluster_size - compr_blocks;
>>>>> +next:
>>>>> +		count -= cluster_size;
>>>>> +	}
>>>>> +
>>>>> +	return released_blocks;
>>>>> +}
>>>>> +
>>>>> +static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
>>>>> +{
>>>>> +	struct inode *inode = file_inode(filp);
>>>>> +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>>>>> +	pgoff_t page_idx = 0, last_idx;
>>>>> +	unsigned int released_blocks = 0;
>>>>> +	int ret;
>>>>> +
>>>>> +	if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
>>>>> +		return -EOPNOTSUPP;
>>>>> +
>>>>> +	if (!f2fs_compressed_file(inode))
>>>>> +		return -EINVAL;
>>>>> +
>>>>> +	if (f2fs_readonly(sbi->sb))
>>>>> +		return -EROFS;
>>>>> +
>>>>> +	ret = mnt_want_write_file(filp);
>>>>> +	if (ret)
>>>>> +		return ret;
>>>>> +
>>>>> +	if (!F2FS_I(inode)->i_compr_blocks)
>>>>> +		goto out;
>>>>> +
>>>>> +	f2fs_balance_fs(F2FS_I_SB(inode), true);
>>>>> +
>>>>> +	inode_lock(inode);
>>>>> +
>>>>> +	if (!IS_IMMUTABLE(inode)) {
>>>>> +		F2FS_I(inode)->i_flags |= F2FS_IMMUTABLE_FL;
>>>>> +		f2fs_set_inode_flags(inode);
>>>>> +		inode->i_ctime = current_time(inode);
>>>>> +		f2fs_mark_inode_dirty_sync(inode, true);
>>>>> +	}
>>>>> +
>>>>> +	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>>>>> +	down_write(&F2FS_I(inode)->i_mmap_sem);
>>>>> +
>>>>> +	last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
>>>>> +
>>>>> +	while (page_idx < last_idx) {
>>>>> +		struct dnode_of_data dn;
>>>>> +		pgoff_t end_offset, count;
>>>>> +
>>>>> +		set_new_dnode(&dn, inode, NULL, NULL, 0);
>>>>> +		ret = f2fs_get_dnode_of_data(&dn, page_idx, LOOKUP_NODE);
>>>>> +		if (ret) {
>>>>> +			if (ret == -ENOENT) {
>>>>> +				page_idx = f2fs_get_next_page_offset(&dn,
>>>>> +								page_idx);
>>>>> +				ret = 0;
>>>>> +				continue;
>>>>> +			}
>>>>> +			break;
>>>>> +		}
>>>>> +
>>>>> +		end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
>>>>> +		count = min(end_offset - dn.ofs_in_node, last_idx - page_idx);
>>>>> +
>>>>> +		ret = release_compress_blocks(&dn, count);
>>>>> +
>>>>> +		f2fs_put_dnode(&dn);
>>>>> +
>>>>> +		if (ret < 0)
>>>>> +			break;
>>>>> +
>>>>> +		page_idx += count;
>>>>> +		released_blocks += ret;
>>>>> +	}
>>>>> +
>>>>> +	up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>>>>> +	up_write(&F2FS_I(inode)->i_mmap_sem);
>>>>> +
>>>>> +	inode_unlock(inode);
>>>>> +out:
>>>>> +	mnt_drop_write_file(filp);
>>>>> +
>>>>> +	if (!ret)
>>>>> +		ret = put_user(released_blocks, (u64 __user *)arg);
>>>>> +
>>>>> +	return ret;
>>>>> +}
>>>>> +
>>>>>  long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>>>  {
>>>>>  	if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
>>>>> @@ -3483,6 +3614,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>>>>  		return f2fs_set_volume_name(filp, arg);
>>>>>  	case F2FS_IOC_GET_COMPRESS_BLOCKS:
>>>>>  		return f2fs_get_compress_blocks(filp, arg);
>>>>> +	case F2FS_IOC_RELEASE_COMPRESS_BLOCKS:
>>>>> +		return f2fs_release_compress_blocks(filp, arg);
>>>>>  	default:
>>>>>  		return -ENOTTY;
>>>>>  	}
>>>>> @@ -3643,6 +3776,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>>>>>  	case F2FS_IOC_GET_VOLUME_NAME:
>>>>>  	case F2FS_IOC_SET_VOLUME_NAME:
>>>>>  	case F2FS_IOC_GET_COMPRESS_BLOCKS:
>>>>> +	case F2FS_IOC_RELEASE_COMPRESS_BLOCKS:
>>>>>  		break;
>>>>>  	default:
>>>>>  		return -ENOIOCTLCMD;
>>>>> -- 
>>>>> 2.18.0.rc1
>>>> .
>>>>
> .
>