Now we support crc32 checksum for superblock.

Signed-off-by: Junling Zheng <zhengjunl...@huawei.com>
---
 fs/f2fs/f2fs.h          |  1 +
 fs/f2fs/super.c         | 28 ++++++++++++++++++++++++++++
 include/linux/f2fs_fs.h |  3 ++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4525f4f82af0..d404ede01fcd 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -147,6 +147,7 @@ struct f2fs_mount_info {
 #define F2FS_FEATURE_INODE_CRTIME      0x0100
 #define F2FS_FEATURE_LOST_FOUND                0x0200
 #define F2FS_FEATURE_VERITY            0x0400  /* reserved */
+#define F2FS_FEATURE_SB_CHKSUM         0x0800
 
 #define F2FS_HAS_FEATURE(sb, mask)                                     \
        ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bd57be470e23..dbb1a2bb9e8e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2149,6 +2149,8 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                                        (bh->b_data + F2FS_SUPER_OFFSET);
        struct super_block *sb = sbi->sb;
        unsigned int blocksize;
+       size_t crc_offset = 0;
+       __u32 crc = 0;
 
        if (F2FS_SUPER_MAGIC != le32_to_cpu(raw_super->magic)) {
                f2fs_msg(sb, KERN_INFO,
@@ -2283,6 +2285,23 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
        if (sanity_check_area_boundary(sbi, bh))
                return 1;
 
+       if (F2FS_HAS_FEATURE(sbi->sb, F2FS_FEATURE_SB_CHKSUM)) {
+               crc_offset = le32_to_cpu(raw_super->checksum_offset);
+               if (crc_offset !=
+                       offsetof(struct f2fs_super_block, crc)) {
+                       f2fs_msg(sb, KERN_INFO,
+                               "Invalid SB checksum offset: %lu",
+                               crc_offset);
+                       return 1;
+               }
+               crc = le32_to_cpu(raw_super->crc);
+               if (!f2fs_crc_valid(sbi, crc, raw_super, crc_offset)) {
+                       f2fs_msg(sb, KERN_INFO,
+                               "Invalid SB checksum value: %u", crc);
+                       return 1;
+               }
+       }
+
        return 0;
 }
 
@@ -2568,6 +2587,7 @@ static int read_raw_super_block(struct f2fs_sb_info *sbi,
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 {
        struct buffer_head *bh;
+       __u32 crc = 0;
        int err;
 
        if ((recover && f2fs_readonly(sbi->sb)) ||
@@ -2576,6 +2596,14 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool 
recover)
                return -EROFS;
        }
 
+       /* we should update superblock crc here */
+       if (!recover &&
+               F2FS_HAS_FEATURE(sbi->sb, F2FS_FEATURE_SB_CHKSUM)) {
+               crc = f2fs_crc32(sbi, F2FS_RAW_SUPER(sbi),
+                               offsetof(struct f2fs_super_block, crc));
+               F2FS_RAW_SUPER(sbi)->crc = crc;
+       }
+
        /* write back-up superblock first */
        bh = sb_bread(sbi->sb, sbi->valid_super_block ? 0 : 1);
        if (!bh)
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index f70f8ac9c4f4..aa4b586569c1 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -112,7 +112,8 @@ struct f2fs_super_block {
        struct f2fs_device devs[MAX_DEVICES];   /* device list */
        __le32 qf_ino[F2FS_MAX_QUOTAS]; /* quota inode numbers */
        __u8 hot_ext_count;             /* # of hot file extension */
-       __u8 reserved[314];             /* valid reserved region */
+       __u8 reserved[310];             /* valid reserved region */
+       __le32 crc;                     /* checksum of superblock */
 } __packed;
 
 /*
-- 
2.18.0


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