Re: [f2fs-dev] [PATCH] f2fs: compress: support chksum

Chao Yu
2020-11-05T01:13:46Z

Jaegeuk,

Any comments?

On 2020/11/3 10:36, Chao Yu wrote:
> On 2020/11/3 10:02, Chao Yu wrote:
>> On 2020/11/3 0:31, Jaegeuk Kim wrote:
>>> On 11/02, Chao Yu wrote:
>>>> This patch supports to store chksum value with compressed
>>>> data, and verify the integrality of compressed data while
>>>> reading the data.
>>>>
>>>> The feature can be enabled through specifying mount option
>>>> 'compress_chksum'.
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>> ---
>>>> Documentation/filesystems/f2fs.rst | 1 +
>>>> fs/f2fs/compress.c | 20 ++++++++++++++++++++
>>>> fs/f2fs/f2fs.h | 13 ++++++++++++-
>>>> fs/f2fs/inode.c | 3 +++
>>>> fs/f2fs/super.c | 9 +++++++++
>>>> include/linux/f2fs_fs.h | 2 +-
>>>> 6 files changed, 46 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
>>>> index b8ee761c9922..985ae7d35066 100644
>>>> --- a/Documentation/filesystems/f2fs.rst
>>>> +++ b/Documentation/filesystems/f2fs.rst
>>>> @@ -260,6 +260,7 @@ compress_extension=%s Support adding specified extension, so that f2fs can enab
>>>> For other files, we can still enable compression via ioctl.
>>>> Note that, there is one reserved special extension '*', it
>>>> can be set to enable compression for all files.
>>>> +compress_chksum Support verifying chksum of raw data in compressed cluster.
>>>> inlinecrypt When possible, encrypt/decrypt the contents of encrypted
>>>> files using the blk-crypto framework rather than
>>>> filesystem-layer encryption. This allows the use of
>>>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>>>> index 14262e0f1cd6..a4e0d2c745b6 100644
>>>> --- a/fs/f2fs/compress.c
>>>> +++ b/fs/f2fs/compress.c
>>>> @@ -602,6 +602,7 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>>>> f2fs_cops[fi->i_compress_algorithm];
>>>> unsigned int max_len, new_nr_cpages;
>>>> struct page **new_cpages;
>>>> + u32 chksum = 0;
>>>> int i, ret;
>>>>
>>>> trace_f2fs_compress_pages_start(cc->inode, cc->cluster_idx,
>>>> @@ -655,6 +656,11 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
>>>>
>>>> cc->cbuf->clen = cpu_to_le32(cc->clen);
>>>>
>>>> + if (fi->i_compress_flag & 1 << COMPRESS_CHKSUM)
>>>> + chksum = f2fs_crc32(F2FS_I_SB(cc->inode),
>>>> + cc->cbuf->cdata, cc->clen);
>>>> + cc->cbuf->chksum = cpu_to_le32(chksum);
>>>> +
>>>> for (i = 0; i < COMPRESS_DATA_RESERVED_SIZE; i++)
>>>> cc->cbuf->reserved[i] = cpu_to_le32(0);
>>>>
>>>> @@ -721,6 +727,7 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
>>>> (struct decompress_io_ctx *)page_private(page);
>>>> struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
>>>> struct f2fs_inode_info *fi= F2FS_I(dic->inode);
>>>> + struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
>>>> const struct f2fs_compress_ops *cops =
>>>> f2fs_cops[fi->i_compress_algorithm];
>>>> int ret;
>>>> @@ -790,6 +797,19 @@ void f2fs_decompress_pages(struct bio *bio, struct page *page, bool verity)
>>>>
>>>> ret = cops->decompress_pages(dic);
>>>>
>>>> + if (!ret && fi->i_compress_flag & 1 << COMPRESS_CHKSUM) {
>>>> + u32 provided = le32_to_cpu(dic->cbuf->chksum);
>>>> + u32 calculated = f2fs_crc32(sbi, dic->cbuf->cdata, dic->clen);
>>>> +
>>>> + if (provided != calculated) {
>>>> + printk_ratelimited(
>>>> + "%sF2FS-fs (%s): checksum invalid, nid = %lu, %x vs %x",
>>>> + KERN_INFO, sbi->sb->s_id, dic->inode->i_ino,
>>>> + provided, calculated);
>>>> + ret = -EFSCORRUPTED;
>>>
>>> Do we need to change fsck.f2fs to recover this?
>
> However, we don't know which one is correct, compressed data or chksum value?
> if compressed data was corrupted, repairing chksum value doesn't help.
>
> Or how about adding chksum values for both raw data and compressed data.
>
> #define COMPRESS_DATA_RESERVED_SIZE 3
> struct compress_data {
> __le32 clen; /* compressed data size */
> + __le32 raw_chksum; /* raw data chksum */
> + __le32 compress_chksum; /* compressed data chksum */
> __le32 reserved[COMPRESS_DATA_RESERVED_SIZE]; /* reserved */
> u8 cdata[]; /* compressed data */
> };
>
> raw_chksum compress_chksum
> match match -> data is verified, pass
> not match match -> repair raw_chksum
> matcth not match -> repair compress_chksum
> not match not match -> corrupted, can not repair
>
> Thanks,
>
>>
>> Yes, prepared to update inode layout in fsck.f2fs w/ kernel side change. >
>> Thanks,
>>
>>>
>>>> + }
>>>> + }
>>>> +
>>>> out_vunmap_cbuf:
>>>> vm_unmap_ram(dic->cbuf, dic->nr_cpages);
>>>> out_vunmap_rbuf:
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 99bcf4b44a9c..2ae254ab7b7d 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -147,7 +147,8 @@ struct f2fs_mount_info {
>>>>
>>>> /* For compression */
>>>> unsigned char compress_algorithm; /* algorithm type */
>>>> - unsigned compress_log_size; /* cluster log size */
>>>> + unsigned char compress_log_size; /* cluster log size */
>>>> + bool compress_chksum; /* compressed data chksum */
>>>> unsigned char compress_ext_cnt; /* extension count */
>>>> unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN]; /* extensions */
>>>> };
>>>> @@ -731,6 +732,7 @@ struct f2fs_inode_info {
>>>> atomic_t i_compr_blocks; /* # of compressed blocks */
>>>> unsigned char i_compress_algorithm; /* algorithm type */
>>>> unsigned char i_log_cluster_size; /* log of cluster size */
>>>> + unsigned short i_compress_flag; /* compress flag */
>>>> unsigned int i_cluster_size; /* cluster size */
>>>> };
>>>>
>>>> @@ -1270,9 +1272,15 @@ enum compress_algorithm_type {
>>>> COMPRESS_MAX,
>>>> };
>>>>
>>>> +enum compress_flag {
>>>> + COMPRESS_CHKSUM,
>>>> + COMPRESS_MAX_FLAG,
>>>> +};
>>>> +
>>>> #define COMPRESS_DATA_RESERVED_SIZE 5
>>>> struct compress_data {
>>>> __le32 clen; /* compressed data size */
>>>> + __le32 chksum; /* compressed data chksum */
>>>> __le32 reserved[COMPRESS_DATA_RESERVED_SIZE]; /* reserved */
>>>> u8 cdata[]; /* compressed data */
>>>> };
>>>> @@ -3882,6 +3890,9 @@ static inline void set_compress_context(struct inode *inode)
>>>> F2FS_OPTION(sbi).compress_algorithm;
>>>> F2FS_I(inode)->i_log_cluster_size =
>>>> F2FS_OPTION(sbi).compress_log_size;
>>>> + F2FS_I(inode)->i_compress_flag =
>>>> + F2FS_OPTION(sbi).compress_chksum ?
>>>> + 1 << COMPRESS_CHKSUM : 0;
>>>> F2FS_I(inode)->i_cluster_size =
>>>> 1 << F2FS_I(inode)->i_log_cluster_size;
>>>> F2FS_I(inode)->i_flags |= F2FS_COMPR_FL;
>>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>>> index 657db2fb6739..de8f7fc89efa 100644
>>>> --- a/fs/f2fs/inode.c
>>>> +++ b/fs/f2fs/inode.c
>>>> @@ -456,6 +456,7 @@ static int do_read_inode(struct inode *inode)
>>>> le64_to_cpu(ri->i_compr_blocks));
>>>> fi->i_compress_algorithm = ri->i_compress_algorithm;
>>>> fi->i_log_cluster_size = ri->i_log_cluster_size;
>>>> + fi->i_compress_flag = ri->i_compress_flag;
>>>> fi->i_cluster_size = 1 << fi->i_log_cluster_size;
>>>> set_inode_flag(inode, FI_COMPRESSED_FILE);
>>>> }
>>>> @@ -634,6 +635,8 @@ void f2fs_update_inode(struct inode *inode, struct page *node_page)
>>>> &F2FS_I(inode)->i_compr_blocks));
>>>> ri->i_compress_algorithm =
>>>> F2FS_I(inode)->i_compress_algorithm;
>>>> + ri->i_compress_flag =
>>>> + cpu_to_le16(F2FS_I(inode)->i_compress_flag);
>>>> ri->i_log_cluster_size =
>>>> F2FS_I(inode)->i_log_cluster_size;
>>>> }
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index 00eff2f51807..f8de4d83a5be 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -146,6 +146,7 @@ enum {
>>>> Opt_compress_algorithm,
>>>> Opt_compress_log_size,
>>>> Opt_compress_extension,
>>>> + Opt_compress_chksum,
>>>> Opt_atgc,
>>>> Opt_err,
>>>> };
>>>> @@ -214,6 +215,7 @@ static match_table_t f2fs_tokens = {
>>>> {Opt_compress_algorithm, "compress_algorithm=%s"},
>>>> {Opt_compress_log_size, "compress_log_size=%u"},
>>>> {Opt_compress_extension, "compress_extension=%s"},
>>>> + {Opt_compress_chksum, "compress_chksum"},
>>>> {Opt_atgc, "atgc"},
>>>> {Opt_err, NULL},
>>>> };
>>>> @@ -934,10 +936,14 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>>>> F2FS_OPTION(sbi).compress_ext_cnt++;
>>>> kfree(name);
>>>> break;
>>>> + case Opt_compress_chksum:
>>>> + F2FS_OPTION(sbi).compress_chksum = true;
>>>> + break;
>>>> #else
>>>> case Opt_compress_algorithm:
>>>> case Opt_compress_log_size:
>>>> case Opt_compress_extension:
>>>> + case Opt_compress_chksum:
>>>> f2fs_info(sbi, "compression options not supported");
>>>> break;
>>>> #endif
>>>> @@ -1523,6 +1529,9 @@ static inline void f2fs_show_compress_options(struct seq_file *seq,
>>>> seq_printf(seq, ",compress_extension=%s",
>>>> F2FS_OPTION(sbi).extensions[i]);
>>>> }
>>>> +
>>>> + if (F2FS_OPTION(sbi).compress_chksum)
>>>> + seq_puts(seq, ",compress_chksum");
>>>> }
>>>>
>>>> static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>>>> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
>>>> index a5dbb57a687f..7dc2a06cf19a 100644
>>>> --- a/include/linux/f2fs_fs.h
>>>> +++ b/include/linux/f2fs_fs.h
>>>> @@ -273,7 +273,7 @@ struct f2fs_inode {
>>>> __le64 i_compr_blocks; /* # of compressed blocks */
>>>> __u8 i_compress_algorithm; /* compress algorithm */
>>>> __u8 i_log_cluster_size; /* log of cluster size */
>>>> - __le16 i_padding; /* padding */
>>>> + __le16 i_compress_flag; /* compress flag */
>>>> __le32 i_extra_end[0]; /* for attribute size calculation */
>>>> } __packed;
>>>> __le32 i_addr[DEF_ADDRS_PER_INODE]; /* Pointers to data blocks */
>>>> --
>>>> 2.26.2
>>> .
>>>
>>
>>
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>> .
>>
>
>
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