[RFC PATCH v2] f2fs: record need_fsck in super_block

Chao Yu
2022-09-13T13:59:41Z

Once CP_ERROR_FLAG is set, checkpoint is disallowed to be triggered to
persist CP_FSCK_FLAG, fsck won't repair the image due to lack of
CP_FSCK_FLAG.

This patch proposes to persist newly introduced SB_NEED_FSCK flag into
super block if CP_ERROR_FLAG and SBI_NEED_FSCK is set, later, once fsck
detect this flag, it can check and repair corrupted image in time.

Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- remove unneeded codes.
fs/f2fs/checkpoint.c | 6 +++++-
fs/f2fs/f2fs.h | 1 +
fs/f2fs/super.c | 26 ++++++++++++++++++++++++++
include/linux/f2fs_fs.h | 5 ++++-
4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index c3119e4c890c..0836fce40394 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -30,8 +30,12 @@ void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io)
{
f2fs_build_fault_attr(sbi, 0, 0);
set_ckpt_flags(sbi, CP_ERROR_FLAG);
- if (!end_io)
+ if (!end_io) {
f2fs_flush_merged_writes(sbi);
+
+ if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
+ f2fs_update_sb_flags(sbi, SB_NEED_FSCK);
+ }
}

/*
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index dee7b67a17a6..1960a98c7555 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3556,6 +3556,7 @@ int f2fs_enable_quota_files(struct f2fs_sb_info *sbi, bool rdonly);
int f2fs_quota_sync(struct super_block *sb, int type);
loff_t max_file_blocks(struct inode *inode);
void f2fs_quota_off_umount(struct super_block *sb);
+void f2fs_update_sb_flags(struct f2fs_sb_info *sbi, unsigned int flag);
int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover);
int f2fs_sync_fs(struct super_block *sb, int sync);
int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b8e5fe244596..c99ba840593d 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3846,6 +3846,32 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
return err;
}

+void f2fs_update_sb_flags(struct f2fs_sb_info *sbi, unsigned int flag)
+{
+ unsigned short s_flags;
+ int err;
+
+ if (le16_to_cpu(F2FS_RAW_SUPER(sbi)->s_flags) & SB_NEED_FSCK)
+ return;
+
+ f2fs_down_write(&sbi->sb_lock);
+
+ s_flags = le16_to_cpu(F2FS_RAW_SUPER(sbi)->s_flags);
+
+ if (s_flags & SB_NEED_FSCK)
+ goto out_unlock;
+
+ F2FS_RAW_SUPER(sbi)->s_flags = cpu_to_le16(s_flags | SB_NEED_FSCK);
+
+ err = f2fs_commit_super(sbi, false);
+ if (err) {
+ f2fs_warn(sbi, "f2fs_commit_super fails to persist flag: %u, err:%d", flag, err);
+ F2FS_RAW_SUPER(sbi)->s_flags = s_flags;
+ }
+out_unlock:
+ f2fs_up_write(&sbi->sb_lock);
+}
+
static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
{
struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index d445150c5350..124176e2a42c 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -73,6 +73,8 @@ struct f2fs_device {
__le32 total_segments;
} __packed;

+#define SB_NEED_FSCK 0x00000001 /* need fsck */
+
struct f2fs_super_block {
__le32 magic; /* Magic Number */
__le16 major_ver; /* Major Version */
@@ -116,7 +118,8 @@ struct f2fs_super_block {
__u8 hot_ext_count; /* # of hot file extension */
__le16 s_encoding; /* Filename charset encoding */
__le16 s_encoding_flags; /* Filename charset encoding flags */
- __u8 reserved[306]; /* valid reserved region */
+ __le16 s_flags; /* super block flags */
+ __u8 reserved[304]; /* valid reserved region */
__le32 crc; /* checksum of superblock */
} __packed;

--
2.25.1