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Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid frequent costly fsck triggers
To:     Jaegeuk Kim <jaegeuk@kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20181128073125.39102-1-jaegeuk@kernel.org>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <724de929-6ee1-3ad7-cfa7-6e80d4e7a3da@huawei.com>
Date:   Wed, 28 Nov 2018 15:54:34 +0800
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Hi Jaeguek,

On 2018/11/28 15:31, Jaegeuk Kim wrote:
> If we want to re-enable nat_bits, we rely on fsck which requires full scan
> of directory tree. Let's do that by regular fsck or unclean shutdown.

Reviewed-by: Chao Yu <yuchao0@huawei.com>

BTW, I have patch made some month ago...

In order to detect nat_bits disabling, could we introduce one more flag for
fsck?

From 86e8bdb2faeec904944bb6621073f4f7de51cc2d Mon Sep 17 00:00:00 2001
From: Chao Yu <yuchao0@huawei.com>
Date: Sun, 9 Sep 2018 05:40:20 +0800
Subject: [PATCH] f2fs: set specified flag after invalidating nat_bits

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/checkpoint.c    | 12 +++++++++++-
 fs/f2fs/f2fs.h          |  3 ++-
 fs/f2fs/node.c          |  3 +++
 include/linux/f2fs_fs.h |  1 +
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 7e17bb3dfcb1..f7fb14e0f5f9 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1226,13 +1226,16 @@ static void update_ckpt_flags(struct f2fs_sb_info
*sbi, struct cp_control *cpc)
 	unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num;
 	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
 	unsigned long flags;
+	bool disable_natbits = false;

 	spin_lock_irqsave(&sbi->cp_lock, flags);

 	if ((cpc->reason & CP_UMOUNT) &&
 			le32_to_cpu(ckpt->cp_pack_total_block_count) >
-			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks)
+			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks) {
 		disable_nat_bits(sbi, false);
+		disable_natbits = true;
+	}

 	if (cpc->reason & CP_TRIMMED)
 		__set_ckpt_flags(ckpt, CP_TRIMMED_FLAG);
@@ -1270,11 +1273,18 @@ static void update_ckpt_flags(struct f2fs_sb_info
*sbi, struct cp_control *cpc)
 	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
 		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);

+	if (is_sbi_flag_set(sbi, SBI_NATBIT_NEED_REPAIR))
+		__set_ckpt_flags(ckpt, CP_NATBIT_NEED_FSCK_FLAG);
+
 	/* 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);
+
+	if (disable_natbits)
+		f2fs_msg(sbi->sb, KERN_NOTICE,
+			"No enough space in CP area, disable nat_bits.");
 }

 static void commit_checkpoint(struct f2fs_sb_info *sbi,
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f0cedbe0c536..b55341c269b2 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1107,6 +1107,7 @@ enum {
 	SBI_QUOTA_NEED_FLUSH,			/* need to flush quota info in CP */
 	SBI_QUOTA_SKIP_FLUSH,			/* skip flushing quota in current CP */
 	SBI_QUOTA_NEED_REPAIR,			/* quota file may be corrupted */
+	SBI_NATBIT_NEED_REPAIR,			/* nat full/empty bitmaps need repair */
 };

 enum {
@@ -1628,7 +1629,7 @@ static inline void disable_nat_bits(struct
f2fs_sb_info *sbi, bool lock)
 {
 	unsigned long flags;

-	set_sbi_flag(sbi, SBI_NEED_FSCK);
+	set_sbi_flag(sbi, SBI_NATBIT_NEED_REPAIR);

 	if (lock)
 		spin_lock_irqsave(&sbi->cp_lock, flags);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index e57add1e8966..0c6f8312a087 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -2902,6 +2902,9 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)

 	cp_ver |= (cur_cp_crc(ckpt) << 32);
 	if (cpu_to_le64(cp_ver) != *(__le64 *)nm_i->nat_bits) {
+		f2fs_msg(sbi->sb, KERN_NOTICE,
+			"Disable nat_bits due to incorrect cp_ver (%llu, %llu)",
+			cp_ver, le64_to_cpu(*(__le64 *)nm_i->nat_bits));
 		disable_nat_bits(sbi, true);
 		return 0;
 	}
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 7196653833fa..1f3ae1504573 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -117,6 +117,7 @@ struct f2fs_super_block {
 /*
  * For checkpoint
  */
+#define CP_NATBIT_NEED_FSCK_FLAG	0X00002000
 #define CP_DISABLED_FLAG		0x00001000
 #define CP_QUOTA_NEED_FSCK_FLAG		0x00000800
 #define CP_LARGE_NAT_BITMAP_FLAG	0x00000400
-- 
2.18.0.rc1


> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/f2fs.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index c28a9d1cb278..aa500239baf2 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1621,7 +1621,11 @@ static inline void disable_nat_bits(struct f2fs_sb_info *sbi, bool lock)
>  {
>  	unsigned long flags;
>  
> -	set_sbi_flag(sbi, SBI_NEED_FSCK);
> +	/*
> +	 * In order to re-enable nat_bits we need to call fsck.f2fs by
> +	 * set_sbi_flag(sbi, SBI_NEED_FSCK). But it may give huge cost,
> +	 * so let's rely on regular fsck or unclean shutdown.
> +	 */
>  
>  	if (lock)
>  		spin_lock_irqsave(&sbi->cp_lock, flags);
>