[03/35] btrfs: use cleanup_extent_op in check_ref_cleanup
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Message ID 20180830174225.2200-4-josef@toxicpanda.com
State New
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Series
  • My current patch queue
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Commit Message

Josef Bacik Aug. 30, 2018, 5:41 p.m. UTC
From: Josef Bacik <jbacik@fb.com>

Unify the extent_op handling as well, just add a flag so we don't
actually run the extent op from check_ref_cleanup and instead return a
value so that we can skip cleaning up the ref head.

Signed-off-by: Josef Bacik <jbacik@fb.com>
---
 fs/btrfs/extent-tree.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Comments

Omar Sandoval Aug. 31, 2018, 11 p.m. UTC | #1
On Thu, Aug 30, 2018 at 01:41:53PM -0400, Josef Bacik wrote:
> From: Josef Bacik <jbacik@fb.com>
> 
> Unify the extent_op handling as well, just add a flag so we don't
> actually run the extent op from check_ref_cleanup and instead return a
> value so that we can skip cleaning up the ref head.
> 
> Signed-off-by: Josef Bacik <jbacik@fb.com>
> ---
>  fs/btrfs/extent-tree.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 4c9fd35bca07..87c42a2c45b1 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2443,18 +2443,23 @@ static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_ref
>  }
>  
>  static int cleanup_extent_op(struct btrfs_trans_handle *trans,
> -			     struct btrfs_delayed_ref_head *head)
> +			     struct btrfs_delayed_ref_head *head,
> +			     bool run_extent_op)
>  {
>  	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
>  	int ret;
>  
>  	if (!extent_op)
>  		return 0;
> +
>  	head->extent_op = NULL;
>  	if (head->must_insert_reserved) {
>  		btrfs_free_delayed_extent_op(extent_op);
>  		return 0;
> +	} else if (!run_extent_op) {
> +		return 1;
>  	}
> +
>  	spin_unlock(&head->lock);
>  	ret = run_delayed_extent_op(trans, head, extent_op);
>  	btrfs_free_delayed_extent_op(extent_op);

So if cleanup_extent_op() returns 1, then the head was unlocked, unless
run_extent_op was true. That's pretty confusing. Can we make it always
unlock in the !must_insert_reserved case?

> @@ -2506,7 +2511,7 @@ static int cleanup_ref_head(struct btrfs_trans_handle *trans,
>  
>  	delayed_refs = &trans->transaction->delayed_refs;
>  
> -	ret = cleanup_extent_op(trans, head);
> +	ret = cleanup_extent_op(trans, head, true);
>  	if (ret < 0) {
>  		unselect_delayed_ref_head(delayed_refs, head);
>  		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
> @@ -6977,12 +6982,8 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
>  	if (!RB_EMPTY_ROOT(&head->ref_tree))
>  		goto out;
>  
> -	if (head->extent_op) {
> -		if (!head->must_insert_reserved)
> -			goto out;
> -		btrfs_free_delayed_extent_op(head->extent_op);
> -		head->extent_op = NULL;
> -	}
> +	if (cleanup_extent_op(trans, head, false))
> +		goto out;
>  
>  	/*
>  	 * waiting for the lock here would deadlock.  If someone else has it
> -- 
> 2.14.3
>
David Sterba Sept. 7, 2018, 11 a.m. UTC | #2
On Fri, Aug 31, 2018 at 04:00:29PM -0700, Omar Sandoval wrote:
> On Thu, Aug 30, 2018 at 01:41:53PM -0400, Josef Bacik wrote:
> > From: Josef Bacik <jbacik@fb.com>
> > 
> > Unify the extent_op handling as well, just add a flag so we don't
> > actually run the extent op from check_ref_cleanup and instead return a
> > value so that we can skip cleaning up the ref head.
> > 
> > Signed-off-by: Josef Bacik <jbacik@fb.com>
> > ---
> >  fs/btrfs/extent-tree.c | 17 +++++++++--------
> >  1 file changed, 9 insertions(+), 8 deletions(-)
> > 
> > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> > index 4c9fd35bca07..87c42a2c45b1 100644
> > --- a/fs/btrfs/extent-tree.c
> > +++ b/fs/btrfs/extent-tree.c
> > @@ -2443,18 +2443,23 @@ static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_ref
> >  }
> >  
> >  static int cleanup_extent_op(struct btrfs_trans_handle *trans,
> > -			     struct btrfs_delayed_ref_head *head)
> > +			     struct btrfs_delayed_ref_head *head,
> > +			     bool run_extent_op)
> >  {
> >  	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
> >  	int ret;
> >  
> >  	if (!extent_op)
> >  		return 0;
> > +
> >  	head->extent_op = NULL;
> >  	if (head->must_insert_reserved) {
> >  		btrfs_free_delayed_extent_op(extent_op);
> >  		return 0;
> > +	} else if (!run_extent_op) {
> > +		return 1;
> >  	}
> > +
> >  	spin_unlock(&head->lock);
> >  	ret = run_delayed_extent_op(trans, head, extent_op);
> >  	btrfs_free_delayed_extent_op(extent_op);
> 
> So if cleanup_extent_op() returns 1, then the head was unlocked, unless
> run_extent_op was true. That's pretty confusing. Can we make it always
> unlock in the !must_insert_reserved case?

Agreed it's confusing. Possibly cleanup_extent_op can be split to two
helpers instead, but the locking semantics should be made more clear.

Patch
diff mbox series

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4c9fd35bca07..87c42a2c45b1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2443,18 +2443,23 @@  static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_ref
 }
 
 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
-			     struct btrfs_delayed_ref_head *head)
+			     struct btrfs_delayed_ref_head *head,
+			     bool run_extent_op)
 {
 	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
 	int ret;
 
 	if (!extent_op)
 		return 0;
+
 	head->extent_op = NULL;
 	if (head->must_insert_reserved) {
 		btrfs_free_delayed_extent_op(extent_op);
 		return 0;
+	} else if (!run_extent_op) {
+		return 1;
 	}
+
 	spin_unlock(&head->lock);
 	ret = run_delayed_extent_op(trans, head, extent_op);
 	btrfs_free_delayed_extent_op(extent_op);
@@ -2506,7 +2511,7 @@  static int cleanup_ref_head(struct btrfs_trans_handle *trans,
 
 	delayed_refs = &trans->transaction->delayed_refs;
 
-	ret = cleanup_extent_op(trans, head);
+	ret = cleanup_extent_op(trans, head, true);
 	if (ret < 0) {
 		unselect_delayed_ref_head(delayed_refs, head);
 		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
@@ -6977,12 +6982,8 @@  static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
 	if (!RB_EMPTY_ROOT(&head->ref_tree))
 		goto out;
 
-	if (head->extent_op) {
-		if (!head->must_insert_reserved)
-			goto out;
-		btrfs_free_delayed_extent_op(head->extent_op);
-		head->extent_op = NULL;
-	}
+	if (cleanup_extent_op(trans, head, false))
+		goto out;
 
 	/*
 	 * waiting for the lock here would deadlock.  If someone else has it