[RFC PATCH 1/2] f2fs: introduce F2FS_IOC_GET_COMPRESS_BLOCKS

[RFC PATCH 1/2] f2fs: introduce F2FS_IOC_GET_COMPRESS_BLOCKS

[Chao Yu]

With this newly introduced interface, user can get block
number compression saved in target inode.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/f2fs.h |  1 +
 fs/f2fs/file.c | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5d047c0bbbbb..15199df5d40a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -426,6 +426,7 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
 #define F2FS_IOC_GET_PIN_FILE		_IOR(F2FS_IOCTL_MAGIC, 14, __u32)
 #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_GET_VOLUME_NAME	FS_IOC_GETFSLABEL
 #define F2FS_IOC_SET_VOLUME_NAME	FS_IOC_SETFSLABEL
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index efca4ed17b7d..235708c892af 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3401,6 +3401,21 @@ static int f2fs_set_volume_name(struct file *filp, unsigned long arg)
 	return err;
 }
 
+static int f2fs_get_compress_blocks(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	__u64 blocks;
+
+	if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
+		return -EOPNOTSUPP;
+
+	if (!f2fs_compressed_file(inode))
+		return -EINVAL;
+
+	blocks = F2FS_I(inode)->i_compr_blocks;
+	return put_user(blocks, (u64 __user *)arg);
+}
+
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
@@ -3479,6 +3494,8 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_get_volume_name(filp, arg);
 	case F2FS_IOC_SET_VOLUME_NAME:
 		return f2fs_set_volume_name(filp, arg);
+	case F2FS_IOC_GET_COMPRESS_BLOCKS:
+		return f2fs_get_compress_blocks(filp, arg);
 	default:
 		return -ENOTTY;
 	}
@@ -3636,6 +3653,7 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case FS_IOC_MEASURE_VERITY:
 	case F2FS_IOC_GET_VOLUME_NAME:
 	case F2FS_IOC_SET_VOLUME_NAME:
+	case F2FS_IOC_GET_COMPRESS_BLOCKS:
 		break;
 	default:
 		return -ENOIOCTLCMD;
-- 
2.18.0.rc1

[RFC PATCH 2/2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

[Chao Yu]

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.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 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

Re: [RFC PATCH 2/2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

[Jaegeuk Kim]

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
filesystem very easily.

> 
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
>  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

Re: [RFC PATCH 2/2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

[Chao Yu]

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 <yuchao0@huawei.com>
>> ---
>>  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
> .
> 

Re: [RFC PATCH 2/2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

[Jaegeuk Kim]

On 02/25, Chao Yu wrote:
> 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?

Can we add a flag in ioctl for both?
Default is checking immutable, but add a flag to force enabling it.

> 
> Thanks,
> 
> > filesystem very easily.
> > 
> >>
> >> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> >> ---
> >>  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
> > .
> > 

Re: [RFC PATCH 2/2] f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS

[Chao Yu]

On 2020/2/27 6:16, Jaegeuk Kim wrote:
> On 02/25, Chao Yu wrote:
>> 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?
> 
> Can we add a flag in ioctl for both?
> Default is checking immutable, but add a flag to force enabling it.

Okay, let me update the patch.

Thanks,

> 
>>
>> Thanks,
>>
>>> filesystem very easily.
>>>
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>> ---
>>>>  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
>>> .
>>>
> .
>