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Date:   Tue, 8 Dec 2020 18:49:10 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, chao@kernel.org
Subject: Re: [PATCH v4] f2fs: compress: support chksum
Message-ID: <X9A7Jn+cHRRcAmIi@google.com>
References: <20201208031437.56627-1-yuchao0@huawei.com>
 <22ac4df6-53ec-fb7c-c4dd-26435352a701@huawei.com>
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On 12/09, Chao Yu wrote:
> Hello guys,
> 
> Any further comments on compress related patches?
> 
> Jaegeuk, could you please queue these patches in dev-test? let me know
> if there is any problem.

Chao, could you please rebase and post them in a series? I lost the patch order
and got some conflicts when trying to merge.

> 
> On 2020/12/8 11:14, 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>
> > ---
> > v4:
> > - enhance readability
> > - remove WARN_ON_ONCE()
> >   Documentation/filesystems/f2fs.rst |  1 +
> >   fs/f2fs/compress.c                 | 22 ++++++++++++++++++++++
> >   fs/f2fs/f2fs.h                     | 16 ++++++++++++++--
> >   fs/f2fs/inode.c                    |  3 +++
> >   fs/f2fs/super.c                    |  9 +++++++++
> >   include/linux/f2fs_fs.h            |  2 +-
> >   6 files changed, 50 insertions(+), 3 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..9313c8695855 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);
> > @@ -790,6 +796,22 @@ 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) {
> > +			if (!is_inode_flag_set(dic->inode, FI_COMPRESS_CORRUPT)) {
> > +				set_inode_flag(dic->inode, FI_COMPRESS_CORRUPT);
> > +				printk_ratelimited(
> > +					"%sF2FS-fs (%s): checksum invalid, nid = %lu, %x vs %x",
> > +					KERN_INFO, sbi->sb->s_id, dic->inode->i_ino,
> > +					provided, calculated);
> > +			}
> > +			set_sbi_flag(sbi, SBI_NEED_FSCK);
> > +		}
> > +	}
> > +
> >   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 0d25f5ca5618..0b314b2034d8 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 */
> >   };
> > @@ -676,6 +677,7 @@ enum {
> >   	FI_ATOMIC_REVOKE_REQUEST, /* request to drop atomic data */
> >   	FI_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
> >   	FI_COMPRESSED_FILE,	/* indicate file's data can be compressed */
> > +	FI_COMPRESS_CORRUPT,	/* indicate compressed cluster is corrupted */
> >   	FI_MMAP_FILE,		/* indicate file was mmapped */
> >   	FI_MAX,			/* max flag, never be used */
> >   };
> > @@ -733,6 +735,7 @@ 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 */
> >   };
> > @@ -1272,9 +1275,15 @@ enum compress_algorithm_type {
> >   	COMPRESS_MAX,
> >   };
> > -#define COMPRESS_DATA_RESERVED_SIZE		5
> > +enum compress_flag {
> > +	COMPRESS_CHKSUM,
> > +	COMPRESS_MAX_FLAG,
> > +};
> > +
> > +#define COMPRESS_DATA_RESERVED_SIZE		4
> >   struct compress_data {
> >   	__le32 clen;			/* compressed data size */
> > +	__le32 chksum;			/* compressed data chksum */
> >   	__le32 reserved[COMPRESS_DATA_RESERVED_SIZE];	/* reserved */
> >   	u8 cdata[];			/* compressed data */
> >   };
> > @@ -3888,6 +3897,9 @@ 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..349d9cb933ee 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 = le16_to_cpu(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 82baaa89c893..f3d919ee4dee 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 */
> >