Re: [PATCH v2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

From: Chao Yu
Date: Thu Mar 05 2020 - 01:34:29 EST


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@xxxxxxxxxx>
>>>>> ---
>>>>> 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
>>>> .
>>>>
> .
>