f2fs: support inode checksum

This patch adds to support inode checksum in f2fs. Signed-off-by: Chao Yu <yuchao0@huawei.com> [Jaegeuk Kim: fix verification flow] Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

fs/f2fs/f2fs.h

@@ -116,6 +116,7 @@ struct f2fs_mount_info {
 #define F2FS_FEATURE_ATOMIC_WRITE0x0004
 #define F2FS_FEATURE_EXTRA_ATTR0x0008
 #define F2FS_FEATURE_PRJQUOTA0x0010
+#define F2FS_FEATURE_INODE_CHKSUM0x0020
 
 #define F2FS_HAS_FEATURE(sb, mask)	\
 ((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
@@ -1085,6 +1086,9 @@ struct f2fs_sb_info {
 /* Reference to checksum algorithm driver via cryptoapi */
 struct crypto_shash *s_chksum_driver;
 
+/* Precomputed FS UUID checksum for seeding other checksums */
+__u32 s_chksum_seed;
+
 /* For fault injection */
 #ifdef CONFIG_F2FS_FAULT_INJECTION
 struct f2fs_fault_info fault_info;
@@ -1176,6 +1180,27 @@ static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc,
 return f2fs_crc32(sbi, buf, buf_size) == blk_crc;
 }
 
+static inline u32 f2fs_chksum(struct f2fs_sb_info *sbi, u32 crc,
+ const void *address, unsigned int length)
+{
+struct {
+struct shash_desc shash;
+char ctx[4];
+} desc;
+int err;
+
+BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != sizeof(desc.ctx));
+
+desc.shash.tfm = sbi->s_chksum_driver;
+desc.shash.flags = 0;
+*(u32 *)desc.ctx = crc;
+
+err = crypto_shash_update(&desc.shash, address, length);
+BUG_ON(err);
+
+return *(u32 *)desc.ctx;
+}
+
 static inline struct f2fs_inode_info *F2FS_I(struct inode *inode)
 {
 return container_of(inode, struct f2fs_inode_info, vfs_inode);
@@ -2285,6 +2310,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
  * inode.c
  */
 void f2fs_set_inode_flags(struct inode *inode);
+bool f2fs_inode_chksum_verify(struct f2fs_sb_info *sbi, struct page *page);
+void f2fs_inode_chksum_set(struct f2fs_sb_info *sbi, struct page *page);
 struct inode *f2fs_iget(struct super_block *sb, unsigned long ino);
 struct inode *f2fs_iget_retry(struct super_block *sb, unsigned long ino);
 int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink);
@@ -2869,6 +2896,11 @@ static inline int f2fs_sb_has_project_quota(struct super_block *sb)
 return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_PRJQUOTA);
 }
 
+static inline int f2fs_sb_has_inode_chksum(struct super_block *sb)
+{
+return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_INODE_CHKSUM);
+}
+
 #ifdef CONFIG_BLK_DEV_ZONED
 static inline int get_blkz_type(struct f2fs_sb_info *sbi,
 struct block_device *bdev, block_t blkaddr)

fs/f2fs/inode.c

@@ -108,6 +108,76 @@ static void __recover_inline_status(struct inode *inode, struct page *ipage)
 return;
 }
 
+static bool f2fs_enable_inode_chksum(struct f2fs_sb_info *sbi, struct page *page)
+{
+struct f2fs_inode *ri = &F2FS_NODE(page)->i;
+int extra_isize = le32_to_cpu(ri->i_extra_isize);
+
+if (!f2fs_sb_has_inode_chksum(sbi->sb))
+return false;
+
+if (!RAW_IS_INODE(F2FS_NODE(page)) || !(ri->i_inline & F2FS_EXTRA_ATTR))
+return false;
+
+if (!F2FS_FITS_IN_INODE(ri, extra_isize, i_inode_checksum))
+return false;
+
+return true;
+}
+
+static __u32 f2fs_inode_chksum(struct f2fs_sb_info *sbi, struct page *page)
+{
+struct f2fs_node *node = F2FS_NODE(page);
+struct f2fs_inode *ri = &node->i;
+__le32 ino = node->footer.ino;
+__le32 gen = ri->i_generation;
+__u32 chksum, chksum_seed;
+__u32 dummy_cs = 0;
+unsigned int offset = offsetof(struct f2fs_inode, i_inode_checksum);
+unsigned int cs_size = sizeof(dummy_cs);
+
+chksum = f2fs_chksum(sbi, sbi->s_chksum_seed, (__u8 *)&ino,
+sizeof(ino));
+chksum_seed = f2fs_chksum(sbi, chksum, (__u8 *)&gen, sizeof(gen));
+
+chksum = f2fs_chksum(sbi, chksum_seed, (__u8 *)ri, offset);
+chksum = f2fs_chksum(sbi, chksum, (__u8 *)&dummy_cs, cs_size);
+offset += cs_size;
+chksum = f2fs_chksum(sbi, chksum, (__u8 *)ri + offset,
+F2FS_BLKSIZE - offset);
+return chksum;
+}
+
+bool f2fs_inode_chksum_verify(struct f2fs_sb_info *sbi, struct page *page)
+{
+struct f2fs_inode *ri;
+__u32 provided, calculated;
+
+if (!f2fs_enable_inode_chksum(sbi, page))
+return true;
+
+ri = &F2FS_NODE(page)->i;
+provided = le32_to_cpu(ri->i_inode_checksum);
+calculated = f2fs_inode_chksum(sbi, page);
+
+if (provided != calculated)
+f2fs_msg(sbi->sb, KERN_WARNING,
+"checksum invalid, ino = %x, %x vs. %x",
+ino_of_node(page), provided, calculated);
+
+return provided == calculated;
+}
+
+void f2fs_inode_chksum_set(struct f2fs_sb_info *sbi, struct page *page)
+{
+struct f2fs_inode *ri = &F2FS_NODE(page)->i;
+
+if (!f2fs_enable_inode_chksum(sbi, page))
+return;
+
+ri->i_inode_checksum = cpu_to_le32(f2fs_inode_chksum(sbi, page));
+}
+
 static int do_read_inode(struct inode *inode)
 {
 struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

fs/f2fs/node.c

@@ -1171,6 +1171,11 @@ static struct page *__get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid,
 err = -EIO;
 goto out_err;
 }
+
+if (!f2fs_inode_chksum_verify(sbi, page)) {
+err = -EBADMSG;
+goto out_err;
+}
 page_hit:
 if(unlikely(nid != nid_of_node(page))) {
 f2fs_msg(sbi->sb, KERN_WARNING, "inconsistent node block, "
@@ -2275,6 +2280,8 @@ int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
 F2FS_FITS_IN_INODE(src, le16_to_cpu(src->i_extra_isize),
 i_projid))
 dst->i_projid = src->i_projid;
+
+f2fs_inode_chksum_set(sbi, ipage);
 }
 
 new_ni = old_ni;

fs/f2fs/segment.c

@@ -2214,9 +2214,12 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
 
 mutex_unlock(&sit_i->sentry_lock);
 
-if (page && IS_NODESEG(type))
+if (page && IS_NODESEG(type)) {
 fill_node_footer_blkaddr(page, NEXT_FREE_BLKADDR(sbi, curseg));
 
+f2fs_inode_chksum_set(sbi, page);
+}
+
 if (add_list) {
 struct f2fs_bio_info *io;
 

fs/f2fs/super.c

@@ -1993,6 +1993,11 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 sb->s_fs_info = sbi;
 sbi->raw_super = raw_super;
 
+/* precompute checksum seed for metadata */
+if (f2fs_sb_has_inode_chksum(sb))
+sbi->s_chksum_seed = f2fs_chksum(sbi, ~0, raw_super->uuid,
+sizeof(raw_super->uuid));
+
 /*
  * The BLKZONED feature indicates that the drive was formatted with
  * zone alignment optimization. This is optional for host-aware

include/linux/f2fs_fs.h

@@ -240,6 +240,7 @@ struct f2fs_inode {
 __le16 i_extra_isize;/* extra inode attribute size */
 __le16 i_padding;/* padding */
 __le32 i_projid;/* project id */
+__le32 i_inode_checksum;/* inode meta checksum */
 __le32 i_extra_end[0];/* for attribute size calculation */
 };
 __le32 i_addr[DEF_ADDRS_PER_INODE];/* Pointers to data blocks */