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Message-ID: <490b5696-b4b3-94ca-f856-e19af9a88ab6@kernel.org>
Date:   Sun, 25 Sep 2022 21:57:37 +0800
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Subject: Re: [RFC PATCH v2] f2fs: record need_fsck in super_block
Content-Language: en-US
To:     Jaegeuk Kim <jaegeuk@kernel.org>
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
References: <20220913135919.2445544-1-chao@kernel.org>
 <YykPzeC4lk+F/U/2@google.com>
 <b22657e3-df59-46ff-81c5-be22e422a576@kernel.org>
 <YyykoT0BdBrXfcrQ@google.com>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <YyykoT0BdBrXfcrQ@google.com>
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On 2022/9/23 2:08, Jaegeuk Kim wrote:
> On 09/20, Chao Yu wrote:
>> On 2022/9/20 8:56, Jaegeuk Kim wrote:
>>> On 09/13, Chao Yu wrote:
>>>> 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);
>>>
>>> Let's think of putting some more context in superblock, if we want to overwrite
>>> it. E.g., a reason to stop checkpoint?
>>
>> Good idea, maybe:
>> Bit	Value				max number of type
>> [0]	need fsck flag			1
>> [1-5]	reason to stop checkpoint	32
>> [6-13]	reason to fsck			256
> 
> How about just keeping the counters of the reasons? (e.g., EIO count which
> stopped checkpoint)
> 
> #define MAX_CRASH_REASON 32
> char array[MAX_CRASH_REASON];

Something like this?

---
  fs/f2fs/checkpoint.c    | 10 +++++++---
  fs/f2fs/data.c          |  6 ++++--
  fs/f2fs/f2fs.h          |  4 +++-
  fs/f2fs/file.c          | 11 ++++++-----
  fs/f2fs/gc.c            |  6 ++++--
  fs/f2fs/inode.c         |  3 ++-
  fs/f2fs/segment.c       |  5 +++--
  fs/f2fs/super.c         | 25 +++++++++++++++++++++++++
  include/linux/f2fs_fs.h | 20 +++++++++++++++++++-
  9 files changed, 73 insertions(+), 17 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 308b70812cbd..b14a8e5eca21 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -26,12 +26,16 @@
  static struct kmem_cache *ino_entry_slab;
  struct kmem_cache *f2fs_inode_entry_slab;

-void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io)
+void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io,
+						unsigned char reason)
  {
  	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);
+
+		f2fs_update_sb_flags(sbi, reason);
+	}
  }

  /*
@@ -122,7 +126,7 @@ struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index)
  		if (PTR_ERR(page) == -EIO &&
  				++count <= DEFAULT_RETRY_IO_COUNT)
  			goto retry;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_META_PAGE);
  	}
  	return page;
  }
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 4e5be2c1dab9..20c8d835a87b 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -333,7 +333,8 @@ static void f2fs_write_end_io(struct bio *bio)
  			mempool_free(page, sbi->write_io_dummy);

  			if (unlikely(bio->bi_status))
-				f2fs_stop_checkpoint(sbi, true);
+				f2fs_stop_checkpoint(sbi, true,
+						STOP_CP_REASON_WRITE_FAIL);
  			continue;
  		}

@@ -349,7 +350,8 @@ static void f2fs_write_end_io(struct bio *bio)
  		if (unlikely(bio->bi_status)) {
  			mapping_set_error(page->mapping, -EIO);
  			if (type == F2FS_WB_CP_DATA)
-				f2fs_stop_checkpoint(sbi, true);
+				f2fs_stop_checkpoint(sbi, true,
+						STOP_CP_REASON_WRITE_FAIL);
  		}

  		f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) &&
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d680a051cba4..ebda0ce1adbf 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3559,6 +3559,7 @@ 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 char reason);
  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);
@@ -3718,7 +3719,8 @@ static inline bool f2fs_need_rand_seg(struct f2fs_sb_info *sbi)
  /*
   * checkpoint.c
   */
-void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io);
+void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io,
+							unsigned char reason);
  void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi);
  struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
  struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 2f9b387fef54..da45798d7fe5 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2153,7 +2153,8 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
  		if (ret) {
  			if (ret == -EROFS) {
  				ret = 0;
-				f2fs_stop_checkpoint(sbi, false);
+				f2fs_stop_checkpoint(sbi, false,
+						STOP_CP_REASON_SHUTDOWN);
  				set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
  				trace_f2fs_shutdown(sbi, in, ret);
  			}
@@ -2166,7 +2167,7 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
  		ret = freeze_bdev(sb->s_bdev);
  		if (ret)
  			goto out;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
  		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
  		thaw_bdev(sb->s_bdev);
  		break;
@@ -2175,16 +2176,16 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
  		ret = f2fs_sync_fs(sb, 1);
  		if (ret)
  			goto out;
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
  		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
  		break;
  	case F2FS_GOING_DOWN_NOSYNC:
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
  		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
  		break;
  	case F2FS_GOING_DOWN_METAFLUSH:
  		f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_META_IO);
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_SHUTDOWN);
  		set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
  		break;
  	case F2FS_GOING_DOWN_NEED_FSCK:
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 3a820e5cdaee..6e42dad0ac2d 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -74,7 +74,8 @@ static int gc_thread_func(void *data)

  		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_FAULT_INJECT);
  		}

  		if (!sb_start_write_trylock(sbi->sb)) {
@@ -1712,7 +1713,8 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
  			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
  				 segno, type, GET_SUM_TYPE((&sum->footer)));
  			set_sbi_flag(sbi, SBI_NEED_FSCK);
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+				STOP_CP_REASON_CORRUPTED_SUMMARY);
  			goto skip;
  		}

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index f6cb8b78b5d5..7880596b51ee 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -716,7 +716,8 @@ void f2fs_update_inode_page(struct inode *inode)
  			cond_resched();
  			goto retry;
  		} else if (err != -ENOENT) {
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_UPDATE_INODE);
  		}
  		return;
  	}
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index e35be4116767..4ed84510f195 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -390,7 +390,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
  {
  	if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  		f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
-		f2fs_stop_checkpoint(sbi, false);
+		f2fs_stop_checkpoint(sbi, false, STOP_CP_REASON_FAULT_INJECT);
  	}

  	/* balance_fs_bg is able to be pending */
@@ -708,7 +708,8 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi)
  		} while (ret && --count);

  		if (ret) {
-			f2fs_stop_checkpoint(sbi, false);
+			f2fs_stop_checkpoint(sbi, false,
+					STOP_CP_REASON_FLUSH_FAIL);
  			break;
  		}

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index b8e5fe244596..9f0a64b4c5c6 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3846,6 +3846,31 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
  	return err;
  }

+void f2fs_update_sb_flags(struct f2fs_sb_info *sbi, unsigned char reason)
+{
+	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
+	unsigned short s_flags;
+	int err;
+
+	f2fs_bug_on(sbi, reason >= MAX_STOP_REASON);
+
+	f2fs_down_write(&sbi->sb_lock);
+
+	raw_super->s_stop_reason[reason]++;
+	
+	s_flags = le16_to_cpu(raw_super->s_flags);
+
+	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
+		raw_super->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, reason:%u err:%d",
+					s_flags | SB_NEED_FSCK, reason, err);
+
+	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..adeaac71a563 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -73,6 +73,22 @@ struct f2fs_device {
  	__le32 total_segments;
  } __packed;

+/* reason of stop_checkpoint */
+enum {
+	STOP_CP_REASON_SHUTDOWN,
+	STOP_CP_REASON_FAULT_INJECT,
+	STOP_CP_REASON_META_PAGE,
+	STOP_CP_REASON_WRITE_FAIL,
+	STOP_CP_REASON_CORRUPTED_SUMMARY,
+	STOP_CP_REASON_UPDATE_INODE,
+	STOP_CP_REASON_FLUSH_FAIL,
+	STOP_CP_REASON_MAX,
+};
+
+#define	MAX_STOP_REASON			32
+
+#define SB_NEED_FSCK			0x00000001	/* need fsck */
+
  struct f2fs_super_block {
  	__le32 magic;			/* Magic Number */
  	__le16 major_ver;		/* Major Version */
@@ -116,7 +132,9 @@ 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 s_stop_reason[MAX_STOP_REASON];	/* stop checkpoint reason */
+	__u8 reserved[272];		/* valid reserved region */
  	__le32 crc;			/* checksum of superblock */
  } __packed;

-- 
2.36.1


> 
>>
>> Thanks
>>
>>>
>>>> +	}
>>>>    }
>>>>    /*
>>>> 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