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Subject: Re: [PATCH v2] exfat: remove EXFAT_SB_DIRTY flag
To:     Sungjong Seo <sj1557.seo@samsung.com>
Cc:     kohada.tetsuhiro@dc.mitsubishielectric.co.jp,
        mori.takahiro@ab.mitsubishielectric.co.jp,
        motai.hirotaka@aj.mitsubishielectric.co.jp,
        'Namjae Jeon' <namjae.jeon@samsung.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
References: <CGME20200616002500epcas1p19135f6f329fbf8c90df1b3ba8a1f67f7@epcas1p1.samsung.com>
 <20200616002450.2522-1-kohada.t2@gmail.com>
 <2c3a01d64382$62b44880$281cd980$@samsung.com>
From:   Tetsuhiro Kohada <kohada.t2@gmail.com>
Message-ID: <f072fc24-1c39-3b01-ab94-1e668a01d1f0@gmail.com>
Date:   Tue, 16 Jun 2020 11:23:32 +0900
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On 2020/06/16 11:03, Sungjong Seo wrote:
>> remove EXFAT_SB_DIRTY flag and related codes.
>>
>> This flag is set/reset in exfat_put_super()/exfat_sync_fs() to avoid
>> sync_blockdev().
>> However ...
>> - exfat_put_super():
>> Before calling this, the VFS has already called sync_filesystem(), so sync
>> is never performed here.
>> - exfat_sync_fs():
>> After calling this, the VFS calls sync_blockdev(), so, it is meaningless
>> to check EXFAT_SB_DIRTY or to bypass sync_blockdev() here.
>> Not only that, but in some cases can't clear VOL_DIRTY.
>> ex:
>> VOL_DIRTY is set when rmdir starts, but when non-empty-dir is detected,
>> return error without setting EXFAT_SB_DIRTY.
>> If performe 'sync' in this state, VOL_DIRTY will not be cleared.
>>
>> Remove the EXFAT_SB_DIRTY check to ensure synchronization.
>> And, remove the code related to the flag.
>>
>> Suggested-by: Sungjong Seo <sj1557.seo@samsung.com>
>> Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
>> ---
>> Changes in v2:
>>   - exfat_sync_fs() avoids synchronous processing when wait=0
>>
>>   fs/exfat/balloc.c   |  4 ++--
>>   fs/exfat/dir.c      | 16 ++++++++--------
>>   fs/exfat/exfat_fs.h |  5 +----
>>   fs/exfat/fatent.c   |  7 ++-----
>>   fs/exfat/misc.c     |  3 +--
>>   fs/exfat/namei.c    | 12 ++++++------
>>   fs/exfat/super.c    | 14 ++++++--------
>>   7 files changed, 26 insertions(+), 35 deletions(-)
>>
>> diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c index
>> 4055eb00ea9b..a987919686c0 100644
>> --- a/fs/exfat/balloc.c
>> +++ b/fs/exfat/balloc.c
>> @@ -158,7 +158,7 @@ int exfat_set_bitmap(struct inode *inode, unsigned int
>> clu)
>>   	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
>>
>>   	set_bit_le(b, sbi->vol_amap[i]->b_data);
>> -	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
>> +	exfat_update_bh(sbi->vol_amap[i], IS_DIRSYNC(inode));
>>   	return 0;
>>   }
>>
>> @@ -180,7 +180,7 @@ void exfat_clear_bitmap(struct inode *inode, unsigned
>> int clu)
>>   	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
>>
>>   	clear_bit_le(b, sbi->vol_amap[i]->b_data);
>> -	exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode));
>> +	exfat_update_bh(sbi->vol_amap[i], IS_DIRSYNC(inode));
>>
>>   	if (opts->discard) {
>>   		int ret_discard;
>> diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index
>> 8e775bd5d523..02acbb6ddf02 100644
>> --- a/fs/exfat/dir.c
>> +++ b/fs/exfat/dir.c
>> @@ -470,7 +470,7 @@ int exfat_init_dir_entry(struct inode *inode, struct
>> exfat_chain *p_dir,
>>   			&ep->dentry.file.access_date,
>>   			NULL);
>>
>> -	exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
>> +	exfat_update_bh(bh, IS_DIRSYNC(inode));
>>   	brelse(bh);
>>
>>   	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector); @@ -
>> 480,7 +480,7 @@ int exfat_init_dir_entry(struct inode *inode, struct
>> exfat_chain *p_dir,
>>   	exfat_init_stream_entry(ep,
>>   		(type == TYPE_FILE) ? ALLOC_FAT_CHAIN : ALLOC_NO_FAT_CHAIN,
>>   		start_clu, size);
>> -	exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
>> +	exfat_update_bh(bh, IS_DIRSYNC(inode));
>>   	brelse(bh);
>>
>>   	return 0;
>> @@ -516,7 +516,7 @@ int exfat_update_dir_chksum(struct inode *inode,
>> struct exfat_chain *p_dir,
>>   	}
>>
>>   	fep->dentry.file.checksum = cpu_to_le16(chksum);
>> -	exfat_update_bh(sb, fbh, IS_DIRSYNC(inode));
>> +	exfat_update_bh(fbh, IS_DIRSYNC(inode));
>>   release_fbh:
>>   	brelse(fbh);
>>   	return ret;
>> @@ -538,7 +538,7 @@ int exfat_init_ext_entry(struct inode *inode, struct
>> exfat_chain *p_dir,
>>   		return -EIO;
>>
>>   	ep->dentry.file.num_ext = (unsigned char)(num_entries - 1);
>> -	exfat_update_bh(sb, bh, sync);
>> +	exfat_update_bh(bh, sync);
>>   	brelse(bh);
>>
>>   	ep = exfat_get_dentry(sb, p_dir, entry + 1, &bh, &sector); @@ -
>> 547,7 +547,7 @@ int exfat_init_ext_entry(struct inode *inode, struct
>> exfat_chain *p_dir,
>>
>>   	ep->dentry.stream.name_len = p_uniname->name_len;
>>   	ep->dentry.stream.name_hash = cpu_to_le16(p_uniname->name_hash);
>> -	exfat_update_bh(sb, bh, sync);
>> +	exfat_update_bh(bh, sync);
>>   	brelse(bh);
>>
>>   	for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) { @@ -556,7
>> +556,7 @@ int exfat_init_ext_entry(struct inode *inode, struct exfat_chain
>> *p_dir,
>>   			return -EIO;
>>
>>   		exfat_init_name_entry(ep, uniname);
>> -		exfat_update_bh(sb, bh, sync);
>> +		exfat_update_bh(bh, sync);
>>   		brelse(bh);
>>   		uniname += EXFAT_FILE_NAME_LEN;
>>   	}
>> @@ -580,7 +580,7 @@ int exfat_remove_entries(struct inode *inode, struct
>> exfat_chain *p_dir,
>>   			return -EIO;
>>
>>   		exfat_set_entry_type(ep, TYPE_DELETED);
>> -		exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
>> +		exfat_update_bh(bh, IS_DIRSYNC(inode));
>>   		brelse(bh);
>>   	}
>>
>> @@ -610,7 +610,7 @@ void exfat_free_dentry_set(struct
>> exfat_entry_set_cache *es, int sync)
>>
>>   	for (i = 0; i < es->num_bh; i++) {
>>   		if (es->modified)
>> -			exfat_update_bh(es->sb, es->bh[i], sync);
>> +			exfat_update_bh(es->bh[i], sync);
>>   		brelse(es->bh[i]);
>>   	}
>>   	kfree(es);
>> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index
>> 595f3117f492..84664024e51e 100644
>> --- a/fs/exfat/exfat_fs.h
>> +++ b/fs/exfat/exfat_fs.h
>> @@ -13,8 +13,6 @@
>>   #define EXFAT_SUPER_MAGIC       0x2011BAB0UL
>>   #define EXFAT_ROOT_INO		1
>>
>> -#define EXFAT_SB_DIRTY		0
>> -
>>   #define EXFAT_CLUSTERS_UNTRACKED (~0u)
>>
>>   /*
>> @@ -238,7 +236,6 @@ struct exfat_sb_info {
>>   	unsigned int clu_srch_ptr; /* cluster search pointer */
>>   	unsigned int used_clusters; /* number of used clusters */
>>
>> -	unsigned long s_state;
>>   	struct mutex s_lock; /* superblock lock */
>>   	struct exfat_mount_options options;
>>   	struct nls_table *nls_io; /* Charset used for input and display */
>> @@ -514,7 +511,7 @@ void exfat_set_entry_time(struct exfat_sb_info *sbi,
>> struct timespec64 *ts,
>>   		u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
>>   u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
>>   u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type); -void
>> exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync);
>> +void exfat_update_bh(struct buffer_head *bh, int sync);
>>   void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
>>   		unsigned int size, unsigned char flags);  void
>> exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec); diff --
>> git a/fs/exfat/fatent.c b/fs/exfat/fatent.c index
>> 4e5c5c9c0f2d..82ee8246c080 100644
>> --- a/fs/exfat/fatent.c
>> +++ b/fs/exfat/fatent.c
>> @@ -75,7 +75,7 @@ int exfat_ent_set(struct super_block *sb, unsigned int
>> loc,
>>
>>   	fat_entry = (__le32 *)&(bh->b_data[off]);
>>   	*fat_entry = cpu_to_le32(content);
>> -	exfat_update_bh(sb, bh, sb->s_flags & SB_SYNCHRONOUS);
>> +	exfat_update_bh(bh, sb->s_flags & SB_SYNCHRONOUS);
>>   	exfat_mirror_bh(sb, sec, bh);
>>   	brelse(bh);
>>   	return 0;
>> @@ -174,7 +174,6 @@ int exfat_free_cluster(struct inode *inode, struct
>> exfat_chain *p_chain)
>>   		return -EIO;
>>   	}
>>
>> -	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
>>   	clu = p_chain->dir;
>>
>>   	if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { @@ -274,7 +273,7 @@ int
>> exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
>>   			goto release_bhs;
>>   		}
>>   		memset(bhs[n]->b_data, 0, sb->s_blocksize);
>> -		exfat_update_bh(sb, bhs[n], 0);
>> +		exfat_update_bh(bhs[n], 0);
>>
>>   		n++;
>>   		blknr++;
>> @@ -358,8 +357,6 @@ int exfat_alloc_cluster(struct inode *inode, unsigned
>> int num_alloc,
>>   		}
>>   	}
>>
>> -	set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
>> -
>>   	p_chain->dir = EXFAT_EOF_CLUSTER;
>>
>>   	while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != diff --
>> git a/fs/exfat/misc.c b/fs/exfat/misc.c index 17d41f3d3709..8a3dde59052b
>> 100644
>> --- a/fs/exfat/misc.c
>> +++ b/fs/exfat/misc.c
>> @@ -163,9 +163,8 @@ u32 exfat_calc_chksum32(void *data, int len, u32
>> chksum, int type)
>>   	return chksum;
>>   }
>>
>> -void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int
>> sync)
>> +void exfat_update_bh(struct buffer_head *bh, int sync)
>>   {
>> -	set_bit(EXFAT_SB_DIRTY, &EXFAT_SB(sb)->s_state);
>>   	set_buffer_uptodate(bh);
>>   	mark_buffer_dirty(bh);
>>
>> diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c index
>> edd8023865a0..5eef2217fcf2 100644
>> --- a/fs/exfat/namei.c
>> +++ b/fs/exfat/namei.c
>> @@ -387,7 +387,7 @@ static int exfat_find_empty_entry(struct inode *inode,
>>   			ep->dentry.stream.valid_size = cpu_to_le64(size);
>>   			ep->dentry.stream.size =
> ep->dentry.stream.valid_size;
>>   			ep->dentry.stream.flags = p_dir->flags;
>> -			exfat_update_bh(sb, bh, IS_DIRSYNC(inode));
>> +			exfat_update_bh(bh, IS_DIRSYNC(inode));
>>   			brelse(bh);
>>   			if (exfat_update_dir_chksum(inode, &(ei->dir),
>>   			    ei->entry))
>> @@ -1071,7 +1071,7 @@ static int exfat_rename_file(struct inode *inode,
>> struct exfat_chain *p_dir,
>>   			epnew->dentry.file.attr |=
> cpu_to_le16(ATTR_ARCHIVE);
>>   			ei->attr |= ATTR_ARCHIVE;
>>   		}
>> -		exfat_update_bh(sb, new_bh, sync);
>> +		exfat_update_bh(new_bh, sync);
>>   		brelse(old_bh);
>>   		brelse(new_bh);
>>
>> @@ -1087,7 +1087,7 @@ static int exfat_rename_file(struct inode *inode,
>> struct exfat_chain *p_dir,
>>   		}
>>
>>   		memcpy(epnew, epold, DENTRY_SIZE);
>> -		exfat_update_bh(sb, new_bh, sync);
>> +		exfat_update_bh(new_bh, sync);
>>   		brelse(old_bh);
>>   		brelse(new_bh);
>>
>> @@ -1104,7 +1104,7 @@ static int exfat_rename_file(struct inode *inode,
>> struct exfat_chain *p_dir,
>>   			epold->dentry.file.attr |=
> cpu_to_le16(ATTR_ARCHIVE);
>>   			ei->attr |= ATTR_ARCHIVE;
>>   		}
>> -		exfat_update_bh(sb, old_bh, sync);
>> +		exfat_update_bh(old_bh, sync);
>>   		brelse(old_bh);
>>   		ret = exfat_init_ext_entry(inode, p_dir, oldentry,
>>   			num_new_entries, p_uniname);
>> @@ -1159,7 +1159,7 @@ static int exfat_move_file(struct inode *inode,
>> struct exfat_chain *p_olddir,
>>   		epnew->dentry.file.attr |= cpu_to_le16(ATTR_ARCHIVE);
>>   		ei->attr |= ATTR_ARCHIVE;
>>   	}
>> -	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
>> +	exfat_update_bh(new_bh, IS_DIRSYNC(inode));
>>   	brelse(mov_bh);
>>   	brelse(new_bh);
>>
>> @@ -1175,7 +1175,7 @@ static int exfat_move_file(struct inode *inode,
>> struct exfat_chain *p_olddir,
>>   	}
>>
>>   	memcpy(epnew, epmov, DENTRY_SIZE);
>> -	exfat_update_bh(sb, new_bh, IS_DIRSYNC(inode));
>> +	exfat_update_bh(new_bh, IS_DIRSYNC(inode));
>>   	brelse(mov_bh);
>>   	brelse(new_bh);
>>
>> diff --git a/fs/exfat/super.c b/fs/exfat/super.c index
>> e650e65536f8..49804d369b51 100644
>> --- a/fs/exfat/super.c
>> +++ b/fs/exfat/super.c
>> @@ -45,9 +45,6 @@ static void exfat_put_super(struct super_block *sb)
>>   	struct exfat_sb_info *sbi = EXFAT_SB(sb);
>>
>>   	mutex_lock(&sbi->s_lock);
>> -	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
>> -		sync_blockdev(sb->s_bdev);
>> -	exfat_set_vol_flags(sb, VOL_CLEAN);
>>   	exfat_free_bitmap(sbi);
>>   	brelse(sbi->boot_bh);
>>   	mutex_unlock(&sbi->s_lock);
>> @@ -60,13 +57,14 @@ static int exfat_sync_fs(struct super_block *sb, int
>> wait)
>>   	struct exfat_sb_info *sbi = EXFAT_SB(sb);
>>   	int err = 0;
>>
>> +	if (!wait)
>> +		return;
> 
> Need to return 0.

I'm sorry.
Reconsider the check before posting.

>> +
>>   	/* If there are some dirty buffers in the bdev inode */
>>   	mutex_lock(&sbi->s_lock);
>> -	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
>> -		sync_blockdev(sb->s_bdev);
>> -		if (exfat_set_vol_flags(sb, VOL_CLEAN))
>> -			err = -EIO;
>> -	}
>> +	sync_blockdev(sb->s_bdev);
>> +	if (exfat_set_vol_flags(sb, VOL_CLEAN))
>> +		err = -EIO;
>>   	mutex_unlock(&sbi->s_lock);
>>   	return err;
>>   }
>> --
>> 2.25.1
> 
>