On 2020/06/05 16:32, Namjae Jeon wrote:
>> Set EXFAT_SB_DIRTY flag in exfat_put_super().
>>
>> In some cases, can't clear VOL_DIRTY with 'sync'.
>> 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.
> Good catch.
> 
> Can you split this patch into two? (Don't set VOL_DIRTY on -ENOTEMPTY and Setting EXFAT_SB_DIRTY is
> merged into exfat_set_vol_flag). I need to check the second one more.

Can't do that.

exfat_set_vol_flag() is called when rmdir processing begins. When Not-empty is detected,
VOL_DIRTY has already been written and synced to the media.

This sequence is same as other write functions.
<begin writing function>
     set VOL_DIRTY (write to the media)
         preparation/state analysis
         update bh & set SB_DIRTY
     clear VOL_DIRTY (cached)
<end>

SB_DIRTY is set when updating bh.
However, in some cases SB_DIRTY is not set.
If SB_DIRTY is not set, exfat_sync_fs() does nothing.

I thought there was a problem with separating VOL_DIRTY and SB_DIRTY.
So I investigated the timing when these are set. Attach the caller graph.
The green box is a function that sets SB_DIRTY directly.
The red box is a function that calls exfat_set_vol_flag() and sets VOL_DIRTY.
VOL_DIRTY is set on all paths before setting SB_DIRTY.

I think VOL_DIRTY and SB_DIRTY should be set at the same time.
That way, It is not necessary to set SB_DIRTY when updating bh.

<begin writing function>
     set VOL_DIRTY (actually write on media), and set SB_DIRTY
         preparation/state analysis
         update data
     clear VOL_DIRTY (cached)
<end>

By doing this, sync is guaranteed if VOL_DIRTY is set by calling exfat_set_vol_flag.

This change may still have problems, but it's little better than before, I think.

BR
---
Tetsuhiro Kohada <kohada.t2@gmail.com>


> 
> Thanks!
>>
>> Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
>> ---
>>   fs/exfat/balloc.c   |  4 ++--
>>   fs/exfat/dir.c      | 18 ++++++++----------
>>   fs/exfat/exfat_fs.h |  2 +-
>>   fs/exfat/fatent.c   |  6 +-----
>>   fs/exfat/misc.c     |  3 +--
>>   fs/exfat/namei.c    | 12 ++++++------
>>   fs/exfat/super.c    |  3 +++
>>   7 files changed, 22 insertions(+), 26 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 3eb8386fb5f2..96c9a817d928 100644
>> --- a/fs/exfat/dir.c
>> +++ b/fs/exfat/dir.c
>> @@ -468,7 +468,7 @@ 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); @@ -478,7 +478,7 @@ 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;
>> @@ -514,7 +514,7 @@ 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;
>> @@ -536,7 +536,7 @@ 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); @@ -545,7 +545,7 @@ 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++) { @@ -554,7 +554,7 @@ 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;
>>   	}
>> @@ -578,7 +578,7 @@ 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);
>>   	}
>>
>> @@ -606,10 +606,8 @@ int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)  {
>>   	int i, err = 0;
>>
>> -	if (es->modified) {
>> -		set_bit(EXFAT_SB_DIRTY, &EXFAT_SB(es->sb)->s_state);
>> +	if (es->modified)
>>   		err = exfat_update_bhs(es->bh, es->num_bh, sync);
>> -	}
>>
>>   	for (i = 0; i < es->num_bh; i++)
>>   		err ? bforget(es->bh[i]):brelse(es->bh[i]);
>> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index f4fa0e833486..0e094d186612 100644
>> --- a/fs/exfat/exfat_fs.h
>> +++ b/fs/exfat/exfat_fs.h
>> @@ -514,7 +514,7 @@ 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);
>>   int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync);  void exfat_chain_set(struct
>> exfat_chain *ec, unsigned int dir,
>>   		unsigned int size, unsigned char flags); diff --git a/fs/exfat/fatent.c
>> b/fs/exfat/fatent.c index 5d11bc2f1b68..f8171183b4c1 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) { @@ -261,7 +260,6 @@ int exfat_zeroed_cluster(struct
>> inode *dir, unsigned int clu)
>>   			memset(bhs[n]->b_data, 0, sb->s_blocksize);
>>   		}
>>
>> -		set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
>>   		err = exfat_update_bhs(bhs, n, IS_DIRSYNC(dir));
>>   		if (err)
>>   			goto release_bhs;
>> @@ -326,8 +324,6 @@ 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 dc34968e99d3..564718747fb2 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 5b0f35329d63..e36c9fc4a5d6 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);
>>
>> @@ -1083,7 +1083,7 @@ static int exfat_rename_file(struct inode *inode, struct exfat_chain *p_dir,
>>   			return -EIO;
>>
>>   		memcpy(epnew, epold, DENTRY_SIZE);
>> -		exfat_update_bh(sb, new_bh, sync);
>> +		exfat_update_bh(new_bh, sync);
>>   		brelse(old_bh);
>>   		brelse(new_bh);
>>
>> @@ -1100,7 +1100,7 @@ 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);
>> @@ -1155,7 +1155,7 @@ 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);
>>
>> @@ -1167,7 +1167,7 @@ static int exfat_move_file(struct inode *inode, struct exfat_chain *p_olddir,
>>   		return -EIO;
>>
>>   	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..199a1e78f9e5 100644
>> --- a/fs/exfat/super.c
>> +++ b/fs/exfat/super.c
>> @@ -104,6 +104,9 @@ int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
>>   	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
>>   	bool sync;
>>
>> +	if (new_flag == VOL_DIRTY)
>> +		set_bit(EXFAT_SB_DIRTY, &sbi->s_state);
>> +
>>   	/* flags are not changed */
>>   	if (sbi->vol_flag == new_flag)
>>   		return 0;
>> --
>> 2.25.1
> 
>