Re: [PATCH] f2fs: compress: support chksum

Chao Yu
2020-11-03T02:02:29Z

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?

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
> .
>