f2fs: allow to recover node blocks given updated checkpoint

If fsck.f2fs changes crc, we have no way to recover some inode blocks by roll-
forward recovery. Let's relax the condition to recover them.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -1157,6 +1157,7 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	/* set this flag to activate crc|cp_ver for recovery */
 	__set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG);
+	__clear_ckpt_flags(ckpt, CP_NOCRC_RECOVERY_FLAG);
 
 	spin_unlock_irqrestore(&sbi->cp_lock, flags);
 }

fs/f2fs/node.h

@@ -305,6 +305,10 @@ static inline bool is_recoverable_dnode(struct page *page)
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
 	__u64 cp_ver = cur_cp_version(ckpt);
 
+	/* Don't care crc part, if fsck.f2fs sets it. */
+	if (__is_set_ckpt_flags(ckpt, CP_NOCRC_RECOVERY_FLAG))
+		return (cp_ver << 32) == (cpver_of_node(page) << 32);
+
 	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG))
 		cp_ver |= (cur_cp_crc(ckpt) << 32);
 

include/linux/f2fs_fs.h

@@ -117,6 +117,7 @@ struct f2fs_super_block {
 /*
  * For checkpoint
  */
+#define CP_NOCRC_RECOVERY_FLAG	0x00000200
 #define CP_TRIMMED_FLAG		0x00000100
 #define CP_NAT_BITS_FLAG	0x00000080
 #define CP_CRC_RECOVERY_FLAG	0x00000040