Messages in this thread Patch in this message | | | Subject | Re: [f2fs-dev] [PATCH] f2fs: compress: support chksum | From | Chao Yu <> | Date | Tue, 10 Nov 2020 09:52:40 +0800 |
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On 2020/11/10 1:06, Jaegeuk Kim wrote: > On 11/09, Chao Yu wrote: >> On 2020/11/7 5:12, Jaegeuk Kim wrote: >>> On 11/03, 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 >>> >>> I think only compress_chksum would be enough. BTW, can we give WARN_ON and >>> marking a FSCK flag without returning EFSCORRUPTED, since we don't really >>> know who was corrupted. If data was corrupted, we should be able to see app >>> corruption. In that case, we can check the kernel log. If checksum was simply >> >> I don't think that app will always corrupt once data was corrupted, I doubt its >> behavior could be slightly abnormal in some cases, e.g. it can just cause apps to >> show wrong number in interaction interface. > > I didn't say we can always get it. But, it's likely to happen with something > like that. > >> >> In this case, if we fix chksum in fsck, the wrong data will never be found due to >> data's chksum matches data itself after repair. > > At least, we should see that log as a hint. > >> >> IMO, the chksum and data was a whole dataset, once they are mismatch, we can >> not trust either of them, fsck should do nothing on them unless we store parity >> bits or replica. > > Yeah, the point is those are not written as a transaction. Three concerns to me:
Just to confirm:
> 1) agreed to see compressed data corruption by checksum
return EFSBADCRC always like we did as inode chksum feature.
2) I don't want to see the error messages all the time
Something like below?
if (provided != calculated) { if (!is_inode_flag_set(,FI_DATA_CORRUPTED)) { printk_ratelimited(); WARN_ON() set_inode_flag(, FI_DATA_CORRUPTED); } return EFSBADCRC; }
3) don't touch the data, even if it was corrupted, since there's no way to fix it.
It seems that we don't need to change fsck.f2fs finally...
Thanks,
> >> >> Thanks, >> >>> corrupted, next fsck will fix the checksum. So, in general, I hope to keep >>> the data as is and raise a flag by the checksum. >>> >>>> 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 >>>>>> . >>>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Linux-f2fs-devel mailing list >>>>> Linux-f2fs-devel@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >>>>> . >>>>> >>> . >>> > . >
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