On 2020/2/25 5:46, Jaegeuk Kim wrote:
> On 02/21, 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.
> 
> I thought we can add compressed_blocks into free space, after converting
> the file to immutable one. Otherwise, this patch is able to corrupt the

Yes, I remember that.

So any suggestion on this patch? we can:
- check immutable flag before releasing space, or
- we can add immutable flag on compressed inode in this ioctl interface?

Thanks,

> filesystem very easily.
> 
>>
>> Signed-off-by: Chao Yu <[email protected]>
>> ---
>>  fs/f2fs/f2fs.h |   6 +++
>>  fs/f2fs/file.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 134 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 15199df5d40a..468f807fd917 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
>> @@ -3957,6 +3959,10 @@ 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 235708c892af..613f87151d90 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -557,6 +557,7 @@ 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);
>> @@ -595,7 +596,9 @@ 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)
>> @@ -3416,6 +3419,127 @@ 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);
>> +
>> +    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)))))
>> @@ -3496,6 +3620,8 @@ 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;
>>      }
>> @@ -3654,6 +3780,7 @@ 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
> .
> 


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