[PATCH 0/7] Fix and cleanups to jbd2

[PATCH 0/7] Fix and cleanups to jbd2

[Kemeng Shi]

This series contains a fix and some random cleanups to jbd2. More
details can be found in respective patches. Thanks!

Kemeng Shi (7):
  jbd2: correctly compare tids with tid_geq function in
    jbd2_fc_begin_commit
  jbd2: remove dead check in journal_alloc_journal_head
  jbd2: remove unused return value of jbd2_fc_release_bufs
  jbd2: remove unneeded kmap for jh_in->b_frozen_data in
    jbd2_journal_write_metadata_buffer
  jbd2: remove unneeded done_copy_out variable in
    jbd2_journal_write_metadata_buffer
  jbd2: correct comment jbd2_mark_journal_empty
  jbd2: remove unneeded check of ret in jbd2_fc_get_buf

 fs/jbd2/journal.c    | 46 +++++++++++++++++---------------------------
 include/linux/jbd2.h |  2 +-
 2 files changed, 19 insertions(+), 29 deletions(-)

-- 
2.30.0

[PATCH 1/7] jbd2: correctly compare tids with tid_geq function in jbd2_fc_begin_commit

[Kemeng Shi]

Use tid_geq to compare tids to work over sequence number wraps.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 1ebf2393bfb7..da5a56d700f1 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -710,7 +710,7 @@ int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
 		return -EINVAL;
 
 	write_lock(&journal->j_state_lock);
-	if (tid <= journal->j_commit_sequence) {
+	if (tid_geq(journal->j_commit_sequence, tid)) {
 		write_unlock(&journal->j_state_lock);
 		return -EALREADY;
 	}
-- 
2.30.0

Re: [PATCH 1/7] jbd2: correctly compare tids with tid_geq function in jbd2_fc_begin_commit

[Jan Kara]

On Tue 30-07-24 19:33:29, Kemeng Shi wrote:
> Use tid_geq to compare tids to work over sequence number wraps.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>  fs/jbd2/journal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Indeed, Luis seems to have missed this when fixing these bugs recently.
Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 1ebf2393bfb7..da5a56d700f1 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -710,7 +710,7 @@ int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
>  		return -EINVAL;
>  
>  	write_lock(&journal->j_state_lock);
> -	if (tid <= journal->j_commit_sequence) {
> +	if (tid_geq(journal->j_commit_sequence, tid)) {
>  		write_unlock(&journal->j_state_lock);
>  		return -EALREADY;
>  	}
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/7] jbd2: correctly compare tids with tid_geq function in jbd2_fc_begin_commit

[Luis Henriques]

On Tue, Jul 30 2024, Jan Kara wrote:

> On Tue 30-07-24 19:33:29, Kemeng Shi wrote:
>> Use tid_geq to compare tids to work over sequence number wraps.
>> 
>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
>> ---
>>  fs/jbd2/journal.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Indeed, Luis seems to have missed this when fixing these bugs recently.

Ah! It looks like I did missed it.  Thanks!

Cheers,
-- 
Luís

> Feel free to add:
>
> Reviewed-by: Jan Kara <jack@suse.cz>
>
> 								Honza
>
>> 
>> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
>> index 1ebf2393bfb7..da5a56d700f1 100644
>> --- a/fs/jbd2/journal.c
>> +++ b/fs/jbd2/journal.c
>> @@ -710,7 +710,7 @@ int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
>>  		return -EINVAL;
>>  
>>  	write_lock(&journal->j_state_lock);
>> -	if (tid <= journal->j_commit_sequence) {
>> +	if (tid_geq(journal->j_commit_sequence, tid)) {
>>  		write_unlock(&journal->j_state_lock);
>>  		return -EALREADY;
>>  	}
>> -- 
>> 2.30.0
>> 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR

Re: [PATCH 1/7] jbd2: correctly compare tids with tid_geq function in jbd2_fc_begin_commit

[Zhang Yi]

On 2024/7/30 19:33, Kemeng Shi wrote:
> Use tid_geq to compare tids to work over sequence number wraps.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

> ---
>  fs/jbd2/journal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 1ebf2393bfb7..da5a56d700f1 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -710,7 +710,7 @@ int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
>  		return -EINVAL;
>  
>  	write_lock(&journal->j_state_lock);
> -	if (tid <= journal->j_commit_sequence) {
> +	if (tid_geq(journal->j_commit_sequence, tid)) {
>  		write_unlock(&journal->j_state_lock);
>  		return -EALREADY;
>  	}
> 

[PATCH 2/7] jbd2: remove dead check in journal_alloc_journal_head

[Kemeng Shi]

We will alloc journal_head with __GFP_NOFAIL anyway, test for failure
is pointless.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index da5a56d700f1..b5d02de1ffff 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2866,8 +2866,7 @@ static struct journal_head *journal_alloc_journal_head(void)
 		ret = kmem_cache_zalloc(jbd2_journal_head_cache,
 				GFP_NOFS | __GFP_NOFAIL);
 	}
-	if (ret)
-		spin_lock_init(&ret->b_state_lock);
+	spin_lock_init(&ret->b_state_lock);
 	return ret;
 }
 
-- 
2.30.0

Re: [PATCH 2/7] jbd2: remove dead check in journal_alloc_journal_head

[Jan Kara]

On Tue 30-07-24 19:33:30, Kemeng Shi wrote:
> We will alloc journal_head with __GFP_NOFAIL anyway, test for failure
> is pointless.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Why not. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/jbd2/journal.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index da5a56d700f1..b5d02de1ffff 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -2866,8 +2866,7 @@ static struct journal_head *journal_alloc_journal_head(void)
>  		ret = kmem_cache_zalloc(jbd2_journal_head_cache,
>  				GFP_NOFS | __GFP_NOFAIL);
>  	}
> -	if (ret)
> -		spin_lock_init(&ret->b_state_lock);
> +	spin_lock_init(&ret->b_state_lock);
>  	return ret;
>  }
>  
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 2/7] jbd2: remove dead check in journal_alloc_journal_head

[Zhang Yi]

On 2024/7/30 19:33, Kemeng Shi wrote:
> We will alloc journal_head with __GFP_NOFAIL anyway, test for failure
> is pointless.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

A nice cleanup.

Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

> ---
>  fs/jbd2/journal.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index da5a56d700f1..b5d02de1ffff 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -2866,8 +2866,7 @@ static struct journal_head *journal_alloc_journal_head(void)
>  		ret = kmem_cache_zalloc(jbd2_journal_head_cache,
>  				GFP_NOFS | __GFP_NOFAIL);
>  	}
> -	if (ret)
> -		spin_lock_init(&ret->b_state_lock);
> +	spin_lock_init(&ret->b_state_lock);
>  	return ret;
>  }
>  
> 

[PATCH 3/7] jbd2: remove unused return value of jbd2_fc_release_bufs

[Kemeng Shi]

Remove unused return value of jbd2_fc_release_bufs.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c    | 4 +---
 include/linux/jbd2.h | 2 +-
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index b5d02de1ffff..312c7575b54f 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -903,7 +903,7 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
 }
 EXPORT_SYMBOL(jbd2_fc_wait_bufs);
 
-int jbd2_fc_release_bufs(journal_t *journal)
+void jbd2_fc_release_bufs(journal_t *journal)
 {
 	struct buffer_head *bh;
 	int i, j_fc_off;
@@ -917,8 +917,6 @@ int jbd2_fc_release_bufs(journal_t *journal)
 		put_bh(bh);
 		journal->j_fc_wbuf[i] = NULL;
 	}
-
-	return 0;
 }
 EXPORT_SYMBOL(jbd2_fc_release_bufs);
 
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index b900c642210c..735229e8ad17 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1665,7 +1665,7 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
 int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
-int jbd2_fc_release_bufs(journal_t *journal);
+void jbd2_fc_release_bufs(journal_t *journal);
 
 /*
  * is_journal_abort
-- 
2.30.0

Re: [PATCH 3/7] jbd2: remove unused return value of jbd2_fc_release_bufs

[Jan Kara]

On Tue 30-07-24 19:33:31, Kemeng Shi wrote:
> Remove unused return value of jbd2_fc_release_bufs.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/jbd2/journal.c    | 4 +---
>  include/linux/jbd2.h | 2 +-
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index b5d02de1ffff..312c7575b54f 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -903,7 +903,7 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
>  }
>  EXPORT_SYMBOL(jbd2_fc_wait_bufs);
>  
> -int jbd2_fc_release_bufs(journal_t *journal)
> +void jbd2_fc_release_bufs(journal_t *journal)
>  {
>  	struct buffer_head *bh;
>  	int i, j_fc_off;
> @@ -917,8 +917,6 @@ int jbd2_fc_release_bufs(journal_t *journal)
>  		put_bh(bh);
>  		journal->j_fc_wbuf[i] = NULL;
>  	}
> -
> -	return 0;
>  }
>  EXPORT_SYMBOL(jbd2_fc_release_bufs);
>  
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index b900c642210c..735229e8ad17 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1665,7 +1665,7 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
>  int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
>  int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
>  int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
> -int jbd2_fc_release_bufs(journal_t *journal);
> +void jbd2_fc_release_bufs(journal_t *journal);
>  
>  /*
>   * is_journal_abort
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 3/7] jbd2: remove unused return value of jbd2_fc_release_bufs

[Zhang Yi]

On 2024/7/30 19:33, Kemeng Shi wrote:
> Remove unused return value of jbd2_fc_release_bufs.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

> ---
>  fs/jbd2/journal.c    | 4 +---
>  include/linux/jbd2.h | 2 +-
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index b5d02de1ffff..312c7575b54f 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -903,7 +903,7 @@ int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
>  }
>  EXPORT_SYMBOL(jbd2_fc_wait_bufs);
>  
> -int jbd2_fc_release_bufs(journal_t *journal)
> +void jbd2_fc_release_bufs(journal_t *journal)
>  {
>  	struct buffer_head *bh;
>  	int i, j_fc_off;
> @@ -917,8 +917,6 @@ int jbd2_fc_release_bufs(journal_t *journal)
>  		put_bh(bh);
>  		journal->j_fc_wbuf[i] = NULL;
>  	}
> -
> -	return 0;
>  }
>  EXPORT_SYMBOL(jbd2_fc_release_bufs);
>  
> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
> index b900c642210c..735229e8ad17 100644
> --- a/include/linux/jbd2.h
> +++ b/include/linux/jbd2.h
> @@ -1665,7 +1665,7 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out);
>  int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode);
>  int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode);
>  int jbd2_fc_wait_bufs(journal_t *journal, int num_blks);
> -int jbd2_fc_release_bufs(journal_t *journal);
> +void jbd2_fc_release_bufs(journal_t *journal);
>  
>  /*
>   * is_journal_abort
> 

[PATCH 4/7] jbd2: remove unneeded kmap for jh_in->b_frozen_data in jbd2_journal_write_metadata_buffer

[Kemeng Shi]

Remove kmap for page of b_frozen_data from jbd2_alloc() which always
provides an address from the direct kernel mapping.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 312c7575b54f..9c1ffb0dc740 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -352,12 +352,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 		done_copy_out = 1;
 		new_folio = virt_to_folio(jh_in->b_frozen_data);
 		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
+		mapped_data = jh_in->b_frozen_data;
 	} else {
 		new_folio = bh_in->b_folio;
 		new_offset = offset_in_folio(new_folio, bh_in->b_data);
+		mapped_data = kmap_local_folio(new_folio, new_offset);
 	}
 
-	mapped_data = kmap_local_folio(new_folio, new_offset);
 	/*
 	 * Fire data frozen trigger if data already wasn't frozen.  Do this
 	 * before checking for escaping, as the trigger may modify the magic
@@ -373,7 +374,8 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 	 */
 	if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))
 		do_escape = 1;
-	kunmap_local(mapped_data);
+	if (!jh_in->b_frozen_data)
+		kunmap_local(mapped_data);
 
 	/*
 	 * Do we need to do a data copy?
-- 
2.30.0

Re: [PATCH 4/7] jbd2: remove unneeded kmap for jh_in->b_frozen_data in jbd2_journal_write_metadata_buffer

[Jan Kara]

On Tue 30-07-24 19:33:32, Kemeng Shi wrote:
> Remove kmap for page of b_frozen_data from jbd2_alloc() which always
> provides an address from the direct kernel mapping.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

I don't think this is really a win. On majority of installations kmap is a
noop anyway and for the remainder kmap_local() is cheap. And the
readability of the code is just worse with this.

								Honza

> ---
>  fs/jbd2/journal.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 312c7575b54f..9c1ffb0dc740 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -352,12 +352,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  		done_copy_out = 1;
>  		new_folio = virt_to_folio(jh_in->b_frozen_data);
>  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
> +		mapped_data = jh_in->b_frozen_data;
>  	} else {
>  		new_folio = bh_in->b_folio;
>  		new_offset = offset_in_folio(new_folio, bh_in->b_data);
> +		mapped_data = kmap_local_folio(new_folio, new_offset);
>  	}
>  
> -	mapped_data = kmap_local_folio(new_folio, new_offset);
>  	/*
>  	 * Fire data frozen trigger if data already wasn't frozen.  Do this
>  	 * before checking for escaping, as the trigger may modify the magic
> @@ -373,7 +374,8 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  	 */
>  	if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))
>  		do_escape = 1;
> -	kunmap_local(mapped_data);
> +	if (!jh_in->b_frozen_data)
> +		kunmap_local(mapped_data);
>  
>  	/*
>  	 * Do we need to do a data copy?
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 4/7] jbd2: remove unneeded kmap for jh_in->b_frozen_data in jbd2_journal_write_metadata_buffer

[Jan Kara]

On Tue 30-07-24 15:32:48, Jan Kara wrote:
> On Tue 30-07-24 19:33:32, Kemeng Shi wrote:
> > Remove kmap for page of b_frozen_data from jbd2_alloc() which always
> > provides an address from the direct kernel mapping.
> > 
> > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> 
> I don't think this is really a win. On majority of installations kmap is a
> noop anyway and for the remainder kmap_local() is cheap. And the
> readability of the code is just worse with this.

Ah, the following patch actually improves the code flow so the end result
looks fine. OK, feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Maybe mention in the changelog that following patch will further improve
the function.

								Honza

> > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> > index 312c7575b54f..9c1ffb0dc740 100644
> > --- a/fs/jbd2/journal.c
> > +++ b/fs/jbd2/journal.c
> > @@ -352,12 +352,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> >  		done_copy_out = 1;
> >  		new_folio = virt_to_folio(jh_in->b_frozen_data);
> >  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
> > +		mapped_data = jh_in->b_frozen_data;
> >  	} else {
> >  		new_folio = bh_in->b_folio;
> >  		new_offset = offset_in_folio(new_folio, bh_in->b_data);
> > +		mapped_data = kmap_local_folio(new_folio, new_offset);
> >  	}
> >  
> > -	mapped_data = kmap_local_folio(new_folio, new_offset);
> >  	/*
> >  	 * Fire data frozen trigger if data already wasn't frozen.  Do this
> >  	 * before checking for escaping, as the trigger may modify the magic
> > @@ -373,7 +374,8 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> >  	 */
> >  	if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))
> >  		do_escape = 1;
> > -	kunmap_local(mapped_data);
> > +	if (!jh_in->b_frozen_data)
> > +		kunmap_local(mapped_data);
> >  
> >  	/*
> >  	 * Do we need to do a data copy?
> > -- 
> > 2.30.0
> > 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

[PATCH 5/7] jbd2: remove unneeded done_copy_out variable in jbd2_journal_write_metadata_buffer

[Kemeng Shi]

It's more intuitive to use jh_in->b_frozen_data directly instead of
done_copy_out variable. Simply remove unneeded done_copy_out variable
and use b_frozen_data instead.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 9c1ffb0dc740..f17d05bc61df 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -318,7 +318,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 				  struct buffer_head **bh_out,
 				  sector_t blocknr)
 {
-	int done_copy_out = 0;
 	int do_escape = 0;
 	char *mapped_data;
 	struct buffer_head *new_bh;
@@ -349,7 +348,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 	 * we use that version of the data for the commit.
 	 */
 	if (jh_in->b_frozen_data) {
-		done_copy_out = 1;
 		new_folio = virt_to_folio(jh_in->b_frozen_data);
 		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
 		mapped_data = jh_in->b_frozen_data;
@@ -357,17 +355,15 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 		new_folio = bh_in->b_folio;
 		new_offset = offset_in_folio(new_folio, bh_in->b_data);
 		mapped_data = kmap_local_folio(new_folio, new_offset);
-	}
-
-	/*
-	 * Fire data frozen trigger if data already wasn't frozen.  Do this
-	 * before checking for escaping, as the trigger may modify the magic
-	 * offset.  If a copy-out happens afterwards, it will have the correct
-	 * data in the buffer.
-	 */
-	if (!done_copy_out)
+		/*
+		 * Fire data frozen trigger if data already wasn't frozen. Do
+		 * this before checking for escaping, as the trigger may modify
+		 * the magic offset.  If a copy-out happens afterwards, it will
+		 * have the correct data in the buffer.
+		 */
 		jbd2_buffer_frozen_trigger(jh_in, mapped_data,
 					   jh_in->b_triggers);
+	}
 
 	/*
 	 * Check for escaping
@@ -380,7 +376,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 	/*
 	 * Do we need to do a data copy?
 	 */
-	if (do_escape && !done_copy_out) {
+	if (do_escape && !jh_in->b_frozen_data) {
 		char *tmp;
 
 		spin_unlock(&jh_in->b_state_lock);
@@ -408,7 +404,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 copy_done:
 		new_folio = virt_to_folio(jh_in->b_frozen_data);
 		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
-		done_copy_out = 1;
 	}
 
 	/*
-- 
2.30.0

Re: [PATCH 5/7] jbd2: remove unneeded done_copy_out variable in jbd2_journal_write_metadata_buffer

[Jan Kara]

On Tue 30-07-24 19:33:33, Kemeng Shi wrote:
> It's more intuitive to use jh_in->b_frozen_data directly instead of
> done_copy_out variable. Simply remove unneeded done_copy_out variable
> and use b_frozen_data instead.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

> @@ -357,17 +355,15 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  		new_folio = bh_in->b_folio;
>  		new_offset = offset_in_folio(new_folio, bh_in->b_data);
>  		mapped_data = kmap_local_folio(new_folio, new_offset);
> -	}
> -
> -	/*
> -	 * Fire data frozen trigger if data already wasn't frozen.  Do this
> -	 * before checking for escaping, as the trigger may modify the magic
> -	 * offset.  If a copy-out happens afterwards, it will have the correct
> -	 * data in the buffer.
> -	 */
> -	if (!done_copy_out)
> +		/*
> +		 * Fire data frozen trigger if data already wasn't frozen. Do
> +		 * this before checking for escaping, as the trigger may modify
> +		 * the magic offset.  If a copy-out happens afterwards, it will
> +		 * have the correct data in the buffer.
> +		 */
>  		jbd2_buffer_frozen_trigger(jh_in, mapped_data,
>  					   jh_in->b_triggers);
> +	}

I like how you've got rid of the conditional. But I'd go further and also
move the escaping check and thus unmap & possible frozen buffer creation
into the branch. Like:

		do_escape = jbd2_data_needs_escaping(mapped_data);
			- create this trivial helper
		kunmap_local(mapped_data);
		if (do_escape) {
			handle b_frozen_data creation
		}

								Honza

>  
>  	/*
>  	 * Check for escaping
> @@ -380,7 +376,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  	/*
>  	 * Do we need to do a data copy?
>  	 */
> -	if (do_escape && !done_copy_out) {
> +	if (do_escape && !jh_in->b_frozen_data) {
>  		char *tmp;
>  
>  		spin_unlock(&jh_in->b_state_lock);
> @@ -408,7 +404,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  copy_done:
>  		new_folio = virt_to_folio(jh_in->b_frozen_data);
>  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
> -		done_copy_out = 1;
>  	}
>  
>  	/*
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 5/7] jbd2: remove unneeded done_copy_out variable in jbd2_journal_write_metadata_buffer

[Kemeng Shi]

on 7/30/2024 9:49 PM, Jan Kara wrote:
> On Tue 30-07-24 19:33:33, Kemeng Shi wrote:
>> It's more intuitive to use jh_in->b_frozen_data directly instead of
>> done_copy_out variable. Simply remove unneeded done_copy_out variable
>> and use b_frozen_data instead.
>>
>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> 
>> @@ -357,17 +355,15 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>>  		new_folio = bh_in->b_folio;
>>  		new_offset = offset_in_folio(new_folio, bh_in->b_data);
>>  		mapped_data = kmap_local_folio(new_folio, new_offset);
>> -	}
>> -
>> -	/*
>> -	 * Fire data frozen trigger if data already wasn't frozen.  Do this
>> -	 * before checking for escaping, as the trigger may modify the magic
>> -	 * offset.  If a copy-out happens afterwards, it will have the correct
>> -	 * data in the buffer.
>> -	 */
>> -	if (!done_copy_out)
>> +		/*
>> +		 * Fire data frozen trigger if data already wasn't frozen. Do
>> +		 * this before checking for escaping, as the trigger may modify
>> +		 * the magic offset.  If a copy-out happens afterwards, it will
>> +		 * have the correct data in the buffer.
>> +		 */
>>  		jbd2_buffer_frozen_trigger(jh_in, mapped_data,
>>  					   jh_in->b_triggers);
>> +	}
> 
> I like how you've got rid of the conditional. But I'd go further and also
> move the escaping check and thus unmap & possible frozen buffer creation
> into the branch. Like:
> 
> 		do_escape = jbd2_data_needs_escaping(mapped_data);
> 			- create this trivial helper
> 		kunmap_local(mapped_data);
> 		if (do_escape) {
> 			handle b_frozen_data creation
> 		}
Thanks Jan. It does look better this way, I will do it in next version.

Kemeng.
> 
> 								Honza
> 
>>  
>>  	/*
>>  	 * Check for escaping
>> @@ -380,7 +376,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>>  	/*
>>  	 * Do we need to do a data copy?
>>  	 */
>> -	if (do_escape && !done_copy_out) {
>> +	if (do_escape && !jh_in->b_frozen_data) {
>>  		char *tmp;
>>  
>>  		spin_unlock(&jh_in->b_state_lock);
>> @@ -408,7 +404,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>>  copy_done:
>>  		new_folio = virt_to_folio(jh_in->b_frozen_data);
>>  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
>> -		done_copy_out = 1;
>>  	}
>>  
>>  	/*
>> -- 
>> 2.30.0
>>

[PATCH 6/7] jbd2: correct comment jbd2_mark_journal_empty

[Kemeng Shi]

After jbd2_mark_journal_empty, journal log is supposed to be empty.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f17d05bc61df..dc18b9f7c999 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1939,7 +1939,7 @@ static void jbd2_mark_journal_empty(journal_t *journal, blk_opf_t write_flags)
 	if (had_fast_commit)
 		jbd2_set_feature_fast_commit(journal);
 
-	/* Log is no longer empty */
+	/* Log is empty */
 	write_lock(&journal->j_state_lock);
 	journal->j_flags |= JBD2_FLUSHED;
 	write_unlock(&journal->j_state_lock);
-- 
2.30.0

Re: [PATCH 6/7] jbd2: correct comment jbd2_mark_journal_empty

[Jan Kara]

On Tue 30-07-24 19:33:34, Kemeng Shi wrote:
> After jbd2_mark_journal_empty, journal log is supposed to be empty.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

							Honza

> ---
>  fs/jbd2/journal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index f17d05bc61df..dc18b9f7c999 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1939,7 +1939,7 @@ static void jbd2_mark_journal_empty(journal_t *journal, blk_opf_t write_flags)
>  	if (had_fast_commit)
>  		jbd2_set_feature_fast_commit(journal);
>  
> -	/* Log is no longer empty */
> +	/* Log is empty */
>  	write_lock(&journal->j_state_lock);
>  	journal->j_flags |= JBD2_FLUSHED;
>  	write_unlock(&journal->j_state_lock);
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 6/7] jbd2: correct comment jbd2_mark_journal_empty

[Zhang Yi]

On 2024/7/30 19:33, Kemeng Shi wrote:
> After jbd2_mark_journal_empty, journal log is supposed to be empty.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

> ---
>  fs/jbd2/journal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index f17d05bc61df..dc18b9f7c999 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1939,7 +1939,7 @@ static void jbd2_mark_journal_empty(journal_t *journal, blk_opf_t write_flags)
>  	if (had_fast_commit)
>  		jbd2_set_feature_fast_commit(journal);
>  
> -	/* Log is no longer empty */
> +	/* Log is empty */
>  	write_lock(&journal->j_state_lock);
>  	journal->j_flags |= JBD2_FLUSHED;
>  	write_unlock(&journal->j_state_lock);
> 

[PATCH 7/7] jbd2: remove unneeded check of ret in jbd2_fc_get_buf

[Kemeng Shi]

Simply return -EINVAL if j_fc_off is invalid to avoid repeated check of
ret.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/jbd2/journal.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index dc18b9f7c999..6f90f7b8e9e5 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -842,12 +842,8 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
 		fc_off = journal->j_fc_off;
 		blocknr = journal->j_fc_first + fc_off;
 		journal->j_fc_off++;
-	} else {
-		ret = -EINVAL;
-	}
-
-	if (ret)
-		return ret;
+	} else
+		return -EINVAL;
 
 	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
 	if (ret)
-- 
2.30.0

Re: [PATCH 7/7] jbd2: remove unneeded check of ret in jbd2_fc_get_buf

[Jan Kara]

On Tue 30-07-24 19:33:35, Kemeng Shi wrote:
> Simply return -EINVAL if j_fc_off is invalid to avoid repeated check of
> ret.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/jbd2/journal.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index dc18b9f7c999..6f90f7b8e9e5 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -842,12 +842,8 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
>  		fc_off = journal->j_fc_off;
>  		blocknr = journal->j_fc_first + fc_off;
>  		journal->j_fc_off++;
> -	} else {
> -		ret = -EINVAL;
> -	}
> -
> -	if (ret)
> -		return ret;
> +	} else
> +		return -EINVAL;
>  
>  	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
>  	if (ret)
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 7/7] jbd2: remove unneeded check of ret in jbd2_fc_get_buf

[Zhang Yi]

On 2024/7/30 19:33, Kemeng Shi wrote:
> Simply return -EINVAL if j_fc_off is invalid to avoid repeated check of
> ret.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>  fs/jbd2/journal.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index dc18b9f7c999..6f90f7b8e9e5 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -842,12 +842,8 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
>  		fc_off = journal->j_fc_off;
>  		blocknr = journal->j_fc_first + fc_off;
>  		journal->j_fc_off++;
> -	} else {
> -		ret = -EINVAL;
> -	}
> -
> -	if (ret)
> -		return ret;
> +	} else
> +		return -EINVAL;
>  

I'd like this style, just a suggestion.

	if (journal->j_fc_off + journal->j_fc_first >= journal->j_fc_last)
		return -EINVAL;

	fc_off = journal->j_fc_off;
	blocknr = journal->j_fc_first + fc_off;
	journal->j_fc_off++;

	...

Thanks,
Yi.


>  	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
>  	if (ret)
> 

Re: [PATCH 7/7] jbd2: remove unneeded check of ret in jbd2_fc_get_buf

[Kemeng Shi]

on 7/31/2024 2:17 PM, Zhang Yi wrote:
> On 2024/7/30 19:33, Kemeng Shi wrote:
>> Simply return -EINVAL if j_fc_off is invalid to avoid repeated check of
>> ret.
>>
>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
>> ---
>>  fs/jbd2/journal.c | 8 ++------
>>  1 file changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
>> index dc18b9f7c999..6f90f7b8e9e5 100644
>> --- a/fs/jbd2/journal.c
>> +++ b/fs/jbd2/journal.c
>> @@ -842,12 +842,8 @@ int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
>>  		fc_off = journal->j_fc_off;
>>  		blocknr = journal->j_fc_first + fc_off;
>>  		journal->j_fc_off++;
>> -	} else {
>> -		ret = -EINVAL;
>> -	}
>> -
>> -	if (ret)
>> -		return ret;
>> +	} else
>> +		return -EINVAL;
>>  
> 
> I'd like this style, just a suggestion.
> 
> 	if (journal->j_fc_off + journal->j_fc_first >= journal->j_fc_last)
> 		return -EINVAL;
> 
> 	fc_off = journal->j_fc_off;
> 	blocknr = journal->j_fc_first + fc_off;
> 	journal->j_fc_off++;
> 
> 	...
> 
Sorry, I miss this. I also think code looks better in this way. I will do
it in next version. Thanks.
> Thanks,
> Yi.
> 
> 
>>  	ret = jbd2_journal_bmap(journal, blocknr, &pblock);
>>  	if (ret)
>>
>